SECTION SLUICE GATES

Transcription

1 SECTION SLUICE GATES PARTl GENERAL 1.1 SECTION INCLUDES A. This section covers all sluice gates required on this project. Each sluice gate shall be furnished and installed complete with wall thimble, operating stem, operating floorstand, and other appurtenances required for a fully functional installation. B. Items included: I. Sluice Gates 2. Manual Operators 3. Accessories 1.2 RELATED SECTIONS: A. Section Grout. 1.3 REFERENCES A. Applicable Standards 1. American National Standards Institute (ANSI): a. B Unified Inch Screw Threads (UN and UNR Thread Form). 2. American Water Works Association (A WWA): a. C Cast Iron Sluice Gates. 3. American Society for Testing and Materials (ASTM): a. A-36- Carbon Structural Steel b. A Steel Bars, Carbon, Cold-Finished, Standard Quality. c. A-123 -Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products. d. A126- Gray Iron Castings for Valves, Flanges and Pipe Fittings. e. A-153 -Zinc Coating (Hot-Dip) on Iron and Steel Hardware. f. Al67- Stainless and Heat-resisting Chromium-Nickel Steel Plate, Sheet and Strip. g. A276- Stainless and Heat-resisting Steel Bars and Shapes. h. B-584- Copper Alloy Sand Castings for General Applications. 4. The Society for Protective Coatings (SSPC): a. SP5 - White Metal Blast Cleaning. 1.4 SUBMITTALS A. The Contractor shall submit the following items required by this Division in accordance with Section Submittals, and Section Contract Closeout. B. Product data for review: Includes, but is not limited to the following: 1. Catalog data or illustrations showing principal parts and materials. 2. Spare parts list. 3. Assembly and disassembly or repair instructions. 4. Detailed layout dimensions. 5. Protective coating system. 6. Leakage testing procedures. 7. Installation, operation and maintenance manuals January 20 13

2 C. Operation and Maintenance Data: 1. Each set of O&M Instructions shall include separate performance criteria and unique characteristics of each gate. Information which applies to all gates may be provided only once per set, if clearly identified as applying to all units. 2. Manuals shall include the required detailed drawings with detailed parts listing, for all gate components. Operation and maintenance manuals shall be submitted for Engineers approval. 1.5 QUALITY ASSURANCE A. Manufacturers shall be experienced in the design and manufacture of equipment and accessories for a minimum period of 5 years. 1.6 DELIVERY, STORAGE AND HANDLING A. Shipment Preparation: Prepare equipment and materials for shipment in a manner to facilitate unloading and handling, and to protect against damage or unnecessary exposure in transit and storage. Include: I. Crates or other suitable packaging materials. 2. Covers and other means to prevent corrosion, moisture damage, mechanical injury and accumulation of dirt in motors, electrical equipment and machinery. 3. Suitable rust-preventative compound on exposed machined surfaces and unpainted iron and steel. 4. Grease packing or oil lubrication in all bearings and similar items. B. Marking: 1. Tag or mark each item of equipment or material as identified in the delivery schedule or on submittals, and include complete packing lists and bills of material with each shipment. Each piece of every item need not be marked separately, provided that all pieces of each item are packed or bundled together and the packages or bundles are properly tagged and marked. 2. Mark partial deliveries of component parts of equipment to identify the equipment, to permit easy accumulation of parts and to facilitate assembly. PART 2 PRODUCTS 2.1 ACCEPT ABLE MANUFACTURERS A. Sluice Gates: 1. Rodney Hunt. 2. Waterman Industries, Inc. 3. Hydro Gate. 4. Fontaine. 5. Whipps, Inc. 6. Engineer-approved equal. 2.2 SLUICE GATES A. Design: Pedestal elevations, gate centerline elevations, shall be as shown on the drawings. Operator type: Handwheel Suitable for operation after periods of inactivity of 1 year or more. Rising stem with stem guides on 10-foot centers maximum. Design shall be suitable for installation as indicated. SKW Project # ?R

3 6. Flush-bottom type, designed so that the neoprene bottom seal may be replaced without removing any concrete; or flange mounted where indicated. 7. Suitable for operation in a corrosive atmosphere of domestic sewage. B. Wall Thimbles: Wall thimbles shall be furnished for all sluice gates that are not attached to pipe flanges. Wall thimbles shall be section "F", section "E", Bell End, or Mechanical Joint. The depth shall be as indicated on the plans and listed in the Gate Schedule. They shall be cast iron, one-piece construction of adequate section to withstand all operational and reasonable installation stresses. Wall thimbles shall be internally braced during concrete placement. A center ring or water stop shall be cast around the periphery of the thimble. The front flange shah be machined and have tapped holes for the sluice gate attaching studs, and metal stamped vertical center lines with the word "top" for correct alignment. Large rectangular wall thimbles shall be provided with holes in the invert to allow air to escape during concrete placement beneath the thimble. A permanent gasket for uniform thickness or suitable mastic shall be provided between the sluice gate and wall thimble. C. Frames: The frame shall be of cast iron, one-piece construction with mounting flange and rectangular or circular opening as indicated on the plans. All contact surfaces of the frame shall be machined. The frame shah have machined dovetailed grooves on the front face into which bronze seat facings shall be driven and machined to a 63 micro-inch finish. The back of the frame shall be machined to bolt directly to the machined face of a wall thimble, pipe flange, or for mounting on the concrete. Frames for sluice gates, greater than 24" wide, subject to unseating heads shall have integrally cast pads machined with keyways to receive top and bottom wedge seats. D. Disc or Slide: The disc shall be of cast iron, one-piece construction, rectangular with integrally cast vertical and horizontal ribs. A reinforcing rib along each side shall be provided to insure rigidity between the side wedges. The disc shall have machined dovetailed grooves on the seating face into which bronze seat facings shall be driven. A tongue on each side, extending the full length of the disc, shall be machined on all sides with a J /I 6" clearance maintained between the disc tongue and gate guide groove. Wedge pads for side, top, and bottom wedges, when required, shall be cast integrally on the disc and machined to receive adjustable bronze wedges. A heavily reinforced nut pocket shall be cast integrally on the vertical centerline and above the horizontal center, and be of such shape to receive the square-backed thrust nut. E. Seat Facings: All seat facings shall be malleable extruded bronze of a composition which shal1 increase in wearing ability with cold working. The extruded seat facings shall be of special shape to fill and permanently lock in the machined dovetailed grooves when driven into place. Attaching pins and screws shall not be allowed. The installed seat facings shall be machined to a 63 micro-inch finish or better. F. Guides: The guides shall be cast iron, one-piece, designed to withstand the total thrust due to water pressure and the wedging action. The guides shall be machined on all contact surfaces, and a groove shall be machined the entire length of the guide to allow 1/16" clearance between the disc tongue and guide groove. The guides shall be of such length as to retain and support at least one half the disc in the full open position. The guides shall be integrally cast with or attached to the frame with silicon bronze or stainless steel studs and nuts, and shall be dowelled to prevent any relative motion between the guides and frame. On sluice gates over 48" wide, a reinforcing rib extending from the guide flange over the top of the wedge seat shall be provided. Bronze wedge seats shall be securely attached to machined pads on the guides. G. Thrust Nut: 1. Designed for all loads during opening and closing. 2. Locked to prevent turning in the slide. 3. Threaded, keyed, or pinned to the stem January 20 13

4 H. Wedges: The wedges shall be solid cast bronze, machined on all contact surfaces. They shall be attached to the disc with studs and nuts and shall have adjusting screws with lock nuts. I. Stem, Stem Couplings, Stem Guides and Stem Cover: 1. Stems: The operating stem shall be of a size to safely withstand, without buckling or permanent distortion, the stresses induced by normal operating forces. In addition, the stem shall be designed to transmit in compression at least 2-1/2 times the rated output of the floorstand or benchstand with a 40 pound effort on the crank or handwheel. The threaded portion of the stem shall have machine cut threads of the 29 Acme type. Stems of more than one section shall be joined by bronze couplings threaded and keyed to the stems. All threaded and keyed couplings of the same size shall be interchangeable. Manually operated, rising stem gates shall be provided with an adjustable stop collar on the stem above the floorstand lift nut. 2. Couplings shall be threaded and keyed, or threaded and bolted. 3. Stem Guides: Stem guides shall be cast iron, bronze bushed, mounted on cast iron brackets. They shall be adjustable in two directions and shall be spaced at sufficient intervals to adequately support the stem. Stem guide spacing shall not exceed and L/r ratio of 200, and shall not be spaced greater than 10 feet except where required by gate travel. 4. Provide Clear Plastic Stem Cover: a. Made of butyrate plastic to withstand weathering. b. With mylar tape to indicate "open" and "closed" positions and gate level in 1" graduations. c. Attached securely to floor stand with noncorrosive materials. J. Flush Bottom Closure: The flush bottom closure type of gate shall have a compressible resilient seal attached to the bottom of the disc (sliding member) with a stainless steel bar and fasteners. The sea] shall be of a specially extruded shape, and designed to accurately fit to the bottom rib of the disc. The seal shall be shaped to produce a wide sealing area on a machined cast iron stop bar that is bolted to the gate frame to form a flush invert. The differential sealing pressure of the resilient seal on the stop bar shall be variable by adjustment of the side wedges on the gate. K. Materials: 1. Gate, frame, pedestal, guides, disc and gear housing: Cast Iron ASTM Al26, Class B or Stainless Steel ASTM A276, Type 304L. 2. Stems, wedges, thrust nuts, seat facings and fasteners, stainless steel, ASTM A276, Type Bolts and adjusting screws: Stainless steel, ASTM A276, Type Threads for gate frame bolts shall be in accordance with ANSI B 1.1 Coarse- Thread series. 5. Handwheel: Cast-iron ASTM Al26, Class B or steel. L. Anchor Bolts or Studs: 1. Furnish stainless steel, ASTM A 167, Type 316 anchor bolts or studs as required for installation of gates and accessories, including: a. Sluice gate frames or thimbles. b. Stem guides. c. Operator pedestals. M. Operators: 1. Factory-mounted on cast-iron pedestal. Provide manual handwheel operator designated manual gates, with a maximum required effort of 40 pounds. 2. Pedestal Height: Approximately 3 feet from bottom of pedestal to centerline of driver. 3. Weatherproof construction. 4. Totally enclosed gearing, with lubrication fittings. 5. Provide pedestal, factory-prime-coated and painted in accordance with A WW A C Mechanical seals or grease lubrication system. 7. Self-locking at any position of the stem travel. SKW Project # ?R

5 PART 3 EXECUTION 3.1 INSTALLATION A. Comply with provisions of A WW A C50 1, C540 and as specified. B. Perform equipment tests during and after startup, to determine whether equipment is performing as specified. C. Furnish and dispose of water required for leakage tests in a manner approved by Engineer. D. Lubricate all bearings and gears before placing gates in operation. E. Leakage Test: Perform field leakage test and submit certified test results per DIVISION 1. Leakage shall not exceed the limits established by A WW A C Furnish bulk heads as required. 2. Minimum seating and unseating head shall be as specified. 3. Minimum test duration shall be 2 hours. 3 2 WARRANTY PROVISIONS A. Contractor shall provide a written warranty from the manufacturer covering all equipment and materials furnished directly or indirectly by the sluice and slide gate supplier. Warranty shall cover parts and labor for any adjustments or repairs required, for a period 1 year from the date of final acceptance by Owner. 3.3 PAINTING AND COATINGS A. Exposed and enclosed machined, gearing surfaces or bearing surfaces shall be coated with water-resistant grease or rust-preventative compound standard of the manufacturer. B. Coating System Cast-iron or Steel Surfaces: 1. Surfaces shall be completely painted, as specified in Section for Steel and Iron Surfaces- Severe and Immersion Service. 2. Provide field touch-up paint. END OF SECTION

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7 SECTION SUBMERSIBLE PUMPS PART 1 GENERAL 1.1 SUMMARY A. General: The Contractor shall furnish and install non-clog pumps at the Influent Pump Station and at the RAS/W AS Pump Station. B. Acceptable System Components: Submersible pumps shall be furnished complete with pump casings, shafts, bearings, seals, lubrication, piping assemblies, guide rails, anchor bolts, motors, controls, power cable, and all other parts and accessories indicated, specified or required for proper installation, operation, and maintenance of a complete system. C. Coordination Responsibility: The pump manufacturer shall be responsible for ensuring that the pumps, motors, and controllers are fully compatible for operation as specified. 1.2 RELATED SECTIONS A. Section Submittals B. Section Material and Equipment C. Section Starting of Systems D. Division 16- Electrical 1.3 REFERENCES: The following publications form a part of these specifications to the extent indicated by references thereto. The revision in effect at the time ofthe Bid Opening shall be applicable. If these publications conflict with the requirements of this section, the section requirements shall govern. A. American National Standards Institute (ANSI): 1. B Cast-Iron Pipe Flanges and Flanged Fittings. B. American Society for Testing and Materials (ASTM): 2. A48- Gray Iron Castings. C. American Iron and Steel Institute (AISI). D. Hydraulic Institute Standards (HIS). E. National Electrical Manufactures Association (NEMA). F. Institute of Electrical and Electronics Engineers (IEEE). G. National Fire Protection Association (NFPA): National Electrical Code (NEC). H. Anti-Friction Bearing Manufacturers Association (AFBMA). I. National Safety Council January

8 1.4 SYSTEM DESCRIPTION A. Design Requirements: See also PUMP SCHEDULE, herein. 1. Pumps shall operate at or near maximum efficiency at rated operating conditions. 2. Pump capacity at rated head shall not exceed specified capacity by more than 5 percent, unless otherwise specified herein. Pumps shall be trimmed to rated conditions. 3. Pump head-capacity curve shall be continuously falling from shutoff head. 4. Pumps shall be stable and have adequate power throughout entire operating head range. 5. Provide totally sealed submersible electrically operated pumps capable of meeting service conditions. 6. Provide pump capable of operating continuously in a dry condition for up to one hour without damage. 7. Pumps shall be able to pump 3-inch diameter spherical solids. 8. The pumps, with its appurtenances and cable, shall be capable of continuous submergence under water without loss of watertight integrity to a depth of sixty-five (65) feet. B. Operational Requirements: 1. Pumps shall be installed in a wetwell as shown on the Drawings. 2. See electrical Drawings and DIVISION 16 for controls and sequence of operation. C. Service Conditions: Pumps shall be capable of pumping the following fluids: 1. Raw screened wastewater. 1.5 SUBMITTALS: The Contractor shall submit the following items required by this division in accordance with Section Submittals: A. Product data for review: 1. Performance curves for each pump model furnished. Curves shall cover range from shutoff to run-out, showing the design flow rate at the conditions specified, and shall be submitted for the following parameters as a function of pump capacity and speed at design temperature: a. Total developed head. b. Required brake horsepower. c. Pump efficiency. d. Required NPSH. e. Minimum recommended submergence. 2. Report of factory tests, as specified herein under "QUALITY ASSURANCE". 3. Control System: a. Control and instrumentation components. b. Control panel layout and dimensions. c. Wiring diagrams. d. Narrative description of operation. e. Certification on manufacturer's letterhead stating that controls will be supplied and warranted by pump manufacturer. 4. Submersible Motors: a. Nameplate information consisting of the following: 1) Manufacturer's name and serial number. 2) Horsepower output. 3) Temperature rise and method indicated. 4) Maximum ambient temperature. 5) Insulation class. 6) RPM at rated load. 7) Frequency. 8) Number of phases. 9) Voltage. 10) Related Load amperes. SKW Project # ?R

9 11) Locked rotor amperes or code letter. 12) Service factor. b. Dimensions for enclosure and shafts. c. Weight. d. Bearing information. e. Certified motor efficiency. 5. Coatings: a. Submit paint type and specifications with submittals. 6. Accessories for wetwell-installed pump stations. B. Warranty for pumps and controls, on manufacturer's letterhead. C. The Pump manufacturer shall provide approved Operation and Maintenance Instructions, which includes the following: 1. Each set of O&M Instructions shall include separate performance criteria and unique characteristics of pump. Information which applies to all pumps may be provided only once per set, if clearly identified as applying to all units. 2. Manuals shall inc1ude the required service training information listed above and shall include detailed drawings with detailed parts listing, wiring diagrams and schematics for all pump components. Operation and maintenance manuals shall be submitted for Engineers approval. 1.6 QUALITY ASSURANCE A. Factory Tests and Reports: 1. Include all manufacturer's standard factory tests on equipment and material per ANSI/HIS standards. 2. Statically balance pump impellers and dynamically balance all pump/motor units such that equipment vibration velocity is less than 0.12-inch per second. 3. Submit results of tests in accordance with DIVISION l. 4. Perform standard tests on all motors in accordance with IEEE MANUFACTURER'S FIELD SERVICES: In accordance with Section Starting of Systems, an authorized representative of the manufacturer shall provide the following: A. Start-up Services: As required, with a minimum of one 8-hour session. B. Demonstration and Training: One 4-hour session shall be provided. 1.8 FACTORY ASSEMBLY A. Pump/motor units shall be completely shop assembled and aligned prior to shipping. B. After completion of the specified factory tests, pumps shall be prepared for shipment with the minimum amount of disassembly, and such that no field disassembly, cleaning, or flushing is required. C. Any components removed for shipping shall be match-marked prior to removal and shipment. D. Prepare surfaces and provide paint system standard of the manufacturer and suitable for service intended

10 1.9 WARRANTY A. Pumping Equipment: The pump manufacturer shall provide a warranty with coverage as given below. Warranty shall not commence before startup of all pumping units by manufacturer's authorized representative, in accordance with Division 1 of the Specifications. 1. The controls shall be covered for two (2) years against defects. Warranty shall cover 100 percent of the cost of both parts and labor for repair or replacement, with no prorating over this term. 2. Pumping units shall be covered for five (5) years against defects in materials and workmanship. Wear items including mechanical seals and bearings shall be covered under the waitanty. Wearing rings may be excluded from the warranty. Obligation of manufacturer under warranty shall be to cover the cost of both parts and labor for replacement. Coverage shall be full and not pro-rated. Owner shall cover the cost of pump delivery to manufacturer's local service center in the Kansas City or St. Louis area. Manufacturer shall cover return shipping. Owner will re-install equipment. B. c. Service Calls: 1. Pump manufacturer or his authorized representative may visit the installation as he sees fit to troubleshoot and inspect the pumps during the warranty period. Manufacturer's service personnel shall contact the Owner at least one working day prior to such visits. 2. When Owner has notified the manufacturer of a problem, manufacturer shall respond promptly. If a pump is out of service or if the controls system is experiencing problems, manufacturer shall arrive to service the installation not more than 48 hours after notification by Owner. A factory trained and authorized technician shall be available to address problems with the pumps and controls. 3. Manufacturer may elect to try and direct Owner's personnel to coitect the problem, if the problem is simple and Owner is able to assist. If unsuccessful, such efforts shall not eliminate manufacturer's responsibility to make a service call. 4. Manufacturer shall maintain a log of all service performed on the equipment during the warranty period, and shall furnish Owner a copy of this log upon request, and at the end of the warranty period. 5. Manufacturer shall provide Owner with necessary forms to accurately keep records of maintenance. Effective Date: The warranty shall become effective upon Substantial Completion of the Work, or the date which the last of the pumps is started, if it occurs first, and has successfully run for a 10 hour period demonstrating; 1) pump capacity with respect to flow, pressure, and current, and 2) pump vibration and balance is acceptable. Warranty shall not commence on the date of delivery nor of shipment. PART 2 PRODUCTS 2.1 ACCEPTABLE MANUFACTURERS A. Manufacturers for the equipment specified in this section shall be selected during the bid phase per the pre-bid approval process as described in the Invitation to Bid. No additions or substitutions will be allowed after the bid opening. 2.2 MATERIALS AND CONSTRUCTION A. Construct motor housing, pump casing, and major pump components of cast iron conforming to ASTM A48, Class 30, 358 or Class 40. B. Provide bolts, anchor bolts, nuts, and washers of AIST Series 300 stainless steel January 20 l3

11 C. Impeller: 1. Cast iron. 2. Impeller Type: As specified in Pump Schedule, herein. 3. The impeller shall be capable of handling solids, stringy materials, sludge, and other debris typically found in wastewater. 4. Secured to shaft with key and self-locking device to prevent slipping in either direction. 5. Balanced statically and dynamically to eliminate vibration and minimize hydraulic thrust. 6. Castings shall not have been repaired by plugging, welding, or other means. 7. Ample impeller diameter to assure first critical speed will occur at not less than 150 percent of rated pump speed. 8. For non-clog type pumps: Provide for efficient sealing on both the volute and impeller by providing wearing rings made of hardened stainless-steel. D. Shaft: l. 2. Shaft shall be machine and polished, AISI Type 403, 416 or 420 stainless steel. Shaft sleeves shall not be acceptable. E. Bearings: 1. Minimum B-1 0 life of 100,000 hours. 2. Pump shaft to rotate on two upper and lower permanently lubricated bearings without end movement. F. Shaft Seal: 1. Two tandem mechanical seals in oil bath reservoir shall seal pumped liquid from motor compartment. Each seal interface shall be held in contact by its own spring system. 2. Upper seal: Faces shall be made of carbon I hardened tool steel, tungsten carbide I carbon, or ceramic. 3. Lower seal: Faces shall be made of silicon carbide versus silicon carbide. 4. The seal shall require neither routine maintenance nor adjustment. The seal system shall not require the pumped liquid as a lubricant. 5. All mechanical seal hardware shall be stainless steel. G. Seal Failure Detection: A moisture detection system shall be provided to detect the presence of water as follows: Leakage sensors shall not be wired in series with motor thermal switches. 1. Capacitance probe(s) shall be provided in the seal chamber. The sensor(s) shall be connected to the external monitoring unit, and when moisture is detected, will activate a seal moisture alarm. The pump will not be shut down. 2. The seal leakage sensors shall be provided in the motor housing to detect the presence of water. 3. The sensors shall be wired separately from the seal leakage sensors, and connected to the external controls, and when moisture is detected, will activate a seal failure alarm and shut down the pump. H. Motors: Motors shall be squirrel-cage induction, shell type design, housed in a watertight chamber. Motor chambers shall be air-filled. Oil-filled motors shall not be acceptable. 1. Motor shall be designed for continuous duty handling pumped media of 104 of. The pump motors shall be capable of up to 10 evenly spaced starts per hour. 2. Stator windings and leads shall be insulated with moisture resistant Class H insulation rated for 180 F. 3. Motors shall be UL or FM rated explosion proof for Class I, Division I, Groups C and D. 4. Combined service factor (combined effect of voltage frequency and specific gravity) shall be a minimum of The motor shall have a voltage tolerance of plus or minus 10 percent. 5. Motors shall be rated for operation with variable frequency drives (VFD) and comply with NEMA MG 1. Motor nameplate shall show turn down of speed and frequency

12 6. Cable entry into the motor junction chamber shall be sealed with elastomeric compression seals. 7. Motors shall be equipped with thermal switches attached to or imbedded in the motor windings and connected in series. These thermal switches shall be used in conjunction with external thermal overload protection and shall be connected to the control panel. One switch shall be provided per stator phase. The tripping of at least one switch shall shut down the motor and activate an alarm. The temperature switches shall automatically reset once the stator temperature returns to normal I. Motor cooling: 1. Wetwell pumps shall be provided with a cooling jacket if recommended by the pump manufacturer by one of the following methods: a. The jacket shall encircle the motor stator housing to provide circulation of a glycol bath around the stator housing for heat dissipation from the motor. b. The jacket shall encircle the motor stator housing to provide circulation of water around the stator housing for heat dissipation from the motor. The pump impeller shall provide the necessary circulation of the liquid through the jacket. The cooling media channels shall be non-clogging by virtue of their dimensions. J. Cables: Pump motor cables shall be type SOW -A, SOW, or MSHA as required. Cable sizing shall conform to NEC, ICEA, and CSA specifications. Cable length shall be sufficient for the pump installation shown on the Drawings with no splices. K. Paint: All exposed hardware shall be of 304 stainless steel. All surfaces coming into contact with pumped liquid other than stainless steel shall be protected at a minimum by a high grade epoxy paint, Tnemec "Series 69" or equal, 8.0- I 0.0 Mils DFT. 2.3 ACCESSORJES A. Pump Discharge Connection: 1. Pump discharge connection elbow and discharge piping shall be installed such that pump will automatically connect and seal to discharge connection elbow when lowered into place. 2. Base elbow connected to discharge piping and anchored to sump floor with stainless steel anchor bolts. Pump supplier shall provide 304L or 316 stainless steel threaded rod anchors 3J4-inch minimum diameter, 5-inch minimum embedment for anchorage of base elbow. Epoxy grout into concrete slab. 3. Designed to receive pump discharge connection without bolts. 4. Integral with guide rail. 5. Cast or ductile iron. 6. Flanges shall conform to ANSI B Seal interface of the pump and discharge elbow by non-sparking metal-to metal contact, or by metal to rubber contact with the use of a profile gasket mechanically held in place between the pump and the sliding guide bracket. B. Pump Lifting: Provide grab-link system, with short length of stainless steel chain, nylon cord, and link attachment device. C. Guide Rails: 1. Stainless-steel pipe. 2. All316 or 304L stainless steel, including rails, brackets, and anchor bolts. 3. Size and number as recommended by pump manufacturer. 4. Shall not support any portion of the pump weight. 5. Provide stainless steel guide rail brackets bolted to discharge riser pipe, at maximum of 12 foot intervals along rails. 6. Provide upper guide rail bracket, cast iron or stainless steel

13 D. Power and Control Cable Holder: L stainless steel, with mounting bracket. 2. Provide grip holders for pump and control cables. 3. Cables shall be easily adjusted to pumping level without splices. 4. Provide power and control cables which are sealed at the motor and continuous from the motor to the panel or intermediate waterproof junction box for removing submersible pump for maintenance. 5. Provide stainless steel Kellems grips for power cords. 2.4 SPARE PARTS A The following spare parts shall be provided: 1. One lower mechanical seal assembly for each model pump furnished. 2. One wearing ring for each pump (if wearing rings are used). 2.5 PUMP PROTECTION SYSTEM: Furnished by pump manufacturer. A. Furnish a complete pump monitoring and protection system consisting of an intrinsically safe solid state monitoring module to be installed in the motor starter cubicle and independent probes integral to the pump/motor, as specified herein, wired to a sealed cable entry terminal box for connection of submersible control cables. B. Monitoring unit (or multiple such) shall be a solid~state module designed for mounting within the motor starter cubicle or as indicated on the Drawings. Monitoring unit shall employ conventional logic and noise isolated electronics. Monitoring unit shall accept inputs from the sensors (seal leakage, motor over temperature) specified and shall output independent contacts which close to alarm each condition, or separate independent output terminals suitable for direct connection to interposing relays for alarm contact development. Provide a separate N.C. alarm contact, rated at 120V, 5A inductive, which opens on any failure. The monitoring unit shall accept separate isolated N.O. contacts which close to indicate pump running and to reset after pump trip. C. Grounding wire shall be installed from the pump motor into the control panel. 2.6 ELECTRICAL EQUIPMENT AND CONTROLS A. Conform to NEC, NEMA, IEEE and DIVISION 16 on all electrical equipment and controls. B. Refer to DIVISION 16 for electrical control panel, motor starters, and pump controls. PART 3 EXECUTION 3.1 INSTALLATION: All Work shall conform to the Drawings, the manufacturer's recommendations, and the requirements of DIVISION I. A. Install access hatch. B. Attach base elbows, guide rails, and make piping connections. C. Make all electrical and control connections, in accordance with DIVISION 16. D. Provide a complete unit with all materials, components and adjustments as required for successful operation

14 3.2 START-UP AND TESTING A. Provide all necessary lubrication for initial start-up, testing and as required for final acceptance. A. Installation, start-up and testing of all equipment and associated construction shall confonn to manufacturer's recommendations. 3.3 ON-SITE PERFORMANCE TESTS A. Conducted by pump manufacturer's authorized representative in presence of Contractor and Engineer. B. Equipment Tests: 1. Check performance of all components as a functioning unit. 1. Check alignment of each unit. 2. Confirm proper rotation of impeller. C. Operational Tests: 1. Conduct such operational tests as necessary to determine that the performance of equipment and controls is as specified. 2. Tests will generally consist of placing equipment in operation under varying conditions and verifying performance (including no-load). a. Test all control sequences and functions. b. Perform complete meg-ohm testing. c. Take amperage and voltage readings. 3. Dry Run Test: No liquid is to be allowed to enter the inlet of the pump. The exterior of the pump shall be dry and remain dry during test. Test duration shall be a minimum of30 minutes. D. Capacity Test: (Pumps in precast manholes only.) On three occasions, wet well shall be filled with liquid to an elevation sufficient to allow each single pump to operate for three minutes, independent of the control regime. Time required to pump down known volume shall be measured as evidence of each pump's capacity. All portions of the force main must have been constructed and tested prior to this test. E. Make all necessary equipment adjustments and corrective work indicated by tests. Repeat testing as necessary. F. Submit a written test report to General Contractor (with one copy to Engineer) in a letter form stating operations performed and results obtained for each unit. END OF SECTION (See Submersible Pump Schedule Following)

15 SUBMERSIBLE PUMP SCHEDULE Description No. ofunits Rated Total Head, feet Minimum Capacity at Rated Total Head, gpm Minimum Shut-Off Head, feet Operating Head Range, feet Minimum Efficiency,% Motor Power (Volts/Ph/Hz) Minimum - Maximum nameplate, hp Impeller Type Minimum Pump Discharge Size, inches Maximum Operating Speed (rpm) Adjustable Frequency Drive Certified Factory Test Required Influent Pump Station /3/ Non-clog Yes Yes RAS/WAS Scum 3 l /3/60 480/3/ Non-clog Non-clog or vortex Yes Yes No No

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17 SECTION SUBMERSIBLE MIXERS PART I GENERAL 1.1 SUMMARY A. General: The Contractor shall furnish and install submersible mixers in the Sludge Pump Station. B. Acceptable System Components: Submersible mixers shall be furnished complete with mixer casings, shafts, bearings, seals, lubrication, guide rails, hoists, anchor bolts, motors, controls, power cable, and all other parts and accessories indicated, specified or required for proper installation, operation, and maintenance. C. Coordination Responsibility: The mixer manufacturer shall be responsible for ensuring that the mixers, motors, and controllers are fully compatible for operation as specified. D. For simplification of support, maintenance, and stocking of parts, one single manufacturer shall supply all equipment specified under this section, and also that specified under Section Submersible Pumps. 1.2 RELATED SECTIONS A. Section Submittals B. Section Material and Equipment c. Section Contract Closeout D. Section Starting of Systems E. Section Piping System Products. F. Section Submersible Pumps G. Division 16 - ELECTRICAL 1.3 REFERENCES: The following publications form a part of these specifications to the extent indicated by references thereto. The revision in effect at the time of the Bid Opening shall be applicable. If these publications conflict with the requirements of this section, the section requirements shall govern. A. American National Standards Institute (ANSI): 1. B16.1- Cast-Iron Pipe Flanges and Flanged Fittings. B. American Society for Testing and Materials (ASTM): 1. A48 - Gray Iron Castings. C. American Iron and Steel Institute (AISI). D. Hydraulic Institute Standards (HIS). E. National Electrical Manufactures's Association (NEMA). F. Institute of Electrical and Electronics Engineers (IEEE) January 2 0 l3

18 G. National Fire Protection Association (NFPA): National Electrical Code (NEC). H. Anti-Friction Bearing Manufacturers Association (AFBMA). I. National Safety Council. 1.4 SYSTEM DESCRIPTION A. Design Requirements: See also MIXER SCHEDULE, herein. 1. Provide totally sealed submersible electrically operated mixers capable of meeting service conditions. 2. The mixers shall be able to be raised and lowered and shall be easily removed for inspection or service without the need for personnel to enter the mixing vessel. A sliding guide bracket shall be an integral part of the mixer unit. The entire weight of the mixer unit shall be guided by a single bracket which must be able to handle all thrust created by the mixer. 3. The mixer, with its appurtenances and cable, shall be capable of continuous submergence under water without loss of watertight integrity to a depth of 130 ft. B. Operational Requirements: 1. SCUM MIXERS: One scum mixers are provided, one in the Sludge Pump Station. The mixer is installed in the concrete scum well with the scum pump. The mixer agitates the clarifier scum to break the solids so the scum pump can pump the material. 2. See electrical Drawings for controls and sequence of operation. C. Service Conditions: Mixers shall be capable of mixing the following fluids: 1. Clarifier Scum. (Scum Mixers) 1.5 SUBMITTALS: The Contractor shall submit the following items required by this division in accordance with Section Submittals and Section Contract Closeout: A. Product data for review: 1. Performance curves for each mixer model furnished. Curves shall cover range from shutoff to run-out, and shall indicate the design mixing flow rate at the conditions specified, and shall be submitted for the following parameters as a function of mixer capacity and speed at design temperature: a. Total developed head for mixers. b. Required brake horsepower. c. Mixer efficiency. d. Minimum recommended submergence. 2. Report of factory tests, for mixers as specified herein under "QUALITY ASSURANCE". 3. Control System: a. Control and instrumentation components. b. Wiring diagrams. 4. Submersible Motors: a. Nameplate information consisting of the following: 1) Manufacturer's name and serial number. 2) Horsepower output. 3) Temperature rise and method indicated. 4) Maximum ambient temperature. 5) Insulation class. 6) RPM at rated load. 7) Frequency

19 8) Number of phases. 9) Voltage. 10) Related Load amperes. 11) Locked rotor amperes or code letter. 12) Service factor. b. Dimensions for enclosure and shafts. c. Weight. d. Bearing information. e. Certified motor efficiency. 5. Coatings: a. Submit paint type and manufacturer's specification with submittals (for cast iron construction). B. The mixer manufacturer shall provide approved Operation and Maintenance Instructions, in accordance with Section Contract Closeout. 1. Each set of O&M Instructions shall include separate performance criteria and unique characteristics of mixer. Information which applies to all mixers may be provided only once per set, if clearly identified as applying to all units. 2. Manuals shall include the required service training information listed above and shall include detailed drawings with detailed parts listing, wiring diagrams and schematics for all mixer components. Operation and maintenance manuals shall be submitted for Engineers approval. 1.6 QUALITY ASSURANCE A. Factory Tests and Reports: 1. Include all manufacturer's standard factory tests on equipment and material. 2. Statically balance mixer propellers and dynamically balance all mixer/motor units such that equipment vibration velocity is less than 0.12-inch per second. 3. Perform standard tests on all motors in accordance with IEEE including but not limited to motor insulation test, cable insulation test, and meggar test. 4. The following tests shall be performed on each mixer prior to shipment from the factory. A quality control check sheet showing the below tests have been accomplished shall be supplied with each mixer. a. Propeller size, motor rating, voltage and phase will be checked for compliance with customer purchase order and specifications. b. A motor and cable check to test for insulation defects and moisture content. c. Pressurize the motor with dry air and check for leaks at all joints and seals. d. Dry run the mixer to check for correct rotation and ensure mechanical integrity. e. The mixer shall be installed in the wet pit on the guide tube assembly and run completely submerged for 30 minutes at a minimum depth of six (6) feet to check for proper amp readings. f. A motor and cable check to test for insulation defects and moisture content after the mixer is removed from the wet pit MANUFACTURER'S FIELD SERVICES: In accordance with Section Starting of Systems, an authorized representative of the manufacturer shall provide the following: A. Start-up Services: As required, with a minimum of one 8-hour session for all mixers. B. Demonstration and Training: One 8-hour session shall be provided. 1.8 FACTORY ASSEMBLY A. Mixer/motor units shall be completely shop assembled and aligned prior to shipping

20 B. After completion of the specified factory tests, mixers shall be prepared for shipment with the minimum amount of disassembly, and such that no field disassembly, cleaning, or flushing is required. C. Any components removed for shipping shall be match-marked prior to removal and shipment. D. Prepare surfaces and provide paint system standard of the manufacturer and suitable for service intended. 1.9 WARRANTY A. Mixing Equipment: The mixer manufacturer shall provide a warranty with coverage as given below. Warranty shall not commence before startup of all mixing units by manufacturer's authorized representative, in accordance with Division I of the Specifications. 1. Mixing units shall be covered for five (5) years against defects in materials and workmanship. Wear items including mechanical seals, bearings, and mast and frame assembly shall be covered under the warranty. Obligation of manufacturer under warranty shall be to cover the cost of both parts and labor for replacement. Coverage shall be full and not pro-rated. Owner shall cover the cost of mixer delivery to manufacturer's local service center in the Kansas City area. Manufacturer shall cover return shipping. Owner will re-install equipment. B. Service Calls: 1. Mixer manufacturer or his authorized representative may visit the installation as he sees fit to troubleshoot and inspect the mixers during the warranty period. Manufacturer's service personnel shall contact the Owner at least one working day prior to such visits. 2. When Owner has notified the manufacturer of a problem, manufacturer shall respond promptly. If a mixer is out of service or if the controls system is experiencing problems, manufacturer shall arrive to service the installation not more than 48 hours after notification by Owner. A factory trained and authorized technician shall be available to address problems with the mixers and controls. 3. Manufacturer may elect to try and direct Owner's personnel to correct the problem, if the problem is simple and Owner is able to assist. If unsuccessful, such efforts shall not eliminate manufacturer's responsibility to make a service call. 4. Manufacturer shall maintain a log of all service performed on the equipment during the warranty period, and shall furnish Owner a copy of this log upon request, and at the end of the warranty period. 5. Manufacturer shall provide Owner with necessary forms to accurately keep records of maintenance. C. Responsibilities of Owner: Owner will be responsible for the following activities: 1. Change the oil in the reservoir at manufacturer's recommended interval, but such interval shall not be required by the warranty to be less than I 2 months. 2. Maintain the mixing units in good working order, including clearing mixer blockages. 3. Allow the mixers to be alternated or exercised regularly to distribute wear and prevent prolonged periods of inactivity. 4. Perform routine troubleshooting and run diagnostics, as outlined in the Operation and Maintenance Instructions. 5. When a problem occurs, perform initial troubleshooting and assessment of situation, eliminating the problem if possible. Contact the manufacturer if expertise or service is required. 6. Owner shall maintain a log of all service performed on the equipment during the warranty period, and shall furnish the manufacturer a copy of this log upon request. D. Effective Date: The warranty shall become effective upon Substantial Completion of the Work, or the date which the last of the mixers is started, if it occurs first

21 PART 2 PRODUCTS 2.1 ACCEPT ABLE MANUFACTURERS A. Manufacturers for the equipment specified in this section shall be selected during the bid phase per the pre-bid approval process as described in the Invitation to Bid. No additions or substitutions will be allowed after the bid opening. 2.2 MATERIALS AND CONSTRUCTION A. Construct motor housing, mixer casing, and major mixer components of cast iron conforming to ASTM A48, Class 35B or Class 40, or 304L stainless steel. B. Provide bolts, anchor bolts, nuts, and washers of AISI Series 300 stainless steel. C. Propeller: Stainless Steel (or polyurethane propellers acceptable for scum mixers only). 2. Self cleaning backward curved design. 3. Precision cut and welded to hub in order to stay within the limits of ISO 1940 G6.3 tolerances such that undue vibration or other unsatisfactory characteristics will not result when the mixer is operating. 4. Balanced statically and dynamically to eliminate vibration and minimize hydraulic thrust. 5. Ample propeller diameter to assure first critical speed will occur at not less than 150 percent of rated mixer speed. 6. Capable of handling solids, fibrous materials, sludge, and other matter normally found in wastewater applications. D. Shaft: Shaft shall be machine and polished, 420 stainless steel, or ANSI 431. Shaft sleeves shall not be acceptable. E. Bearings: 1. Minimum 8-10 life of 100,000 hours. 2. Mixer shaft to rotate on a minimum of two permanently lubricated bearings without end movement. 1. Bearings shall be of single row, deep grooved design and sized to transfer all radial and axial loads to the mixer housing and minimize shaft deflection. F. Shaft Seal: 1. A two seal system consisting of a mechanical seal on the outer side and a radial shaft seal or a mechanical seal on the inner side, each working independently of the other shall seal mixed liquid from the motor compartment. 2. Mechanical seals shall contain both stationary and rotary silicon carbide faced rings. Other materials will not be acceptable. 3. The seal shall require neither routine maintenance nor adjustment. The seal system shall not require the mixed liquid as a lubricant. 4. All mechanical seal hardware shall be stainless steel. 5. In order to avoid seal failure due to sticking, clogging, and misalignment from elements contained in the mixed media, only the seal faces of the outer seal assembly and its retaining clips shall be exposed to the mixed media. All other components shall be contained in the oil housing. All seal faces must also be capable of relapping. G. Flow Rings: I. Mixers shall be provided without shrouds and flow rings

22 H. Seal Failure Detection: A moisture detection system shall be provided to detect the presence of water as follows. Leakage sensors shall not be wired in series with motor thermal switches. Capacitance probe(s) shall be provided in the seal chamber. The sensor(s) will be connected to the external monitoring unit~ and when moisture is detected, will activate a seal moisture alarm. The mixer will not be shut down. 1. If seal leakage sensors are not available from mixer manufacturer~ float switch( es) may be provided in the motor housing to detect the presence of water. The sensors shall be wired to the external controls, and when moisture is detected, will activate a seal failure alarm and shut down the mixer. I. Motors: Motors shall be squirrel-cage induction, shell type design, housed in a watertight chamber. Motor chambers shall be air-filled. Oil-filled motors shall not be acceptable. 1. Motor shall be designed for continuous duty handling mixed media of 104 F and capable of up to 10 evenly spaced starts per hour. 2. Stator windings and leads shall be insulated with moisture resistant Class F insulation rated for 155 F. The stator shall be dipped and baked three (3) times in Class F varnish. 3. The rotor bars and short circuit rings shall be constructed of aluminum. 4. Motors shall be UL or FM rated explosion proof for Class I, Division I, Groups C and D. 5. Combined service factor (combined effect of voltage frequency and specific gravity) shall be a minimum of The motor shall have a voltage tolerance of plus or minus 10 percent. 6. Cable entry into the motor junction chamber shall be sealed with elastomeric compression seals. 7. Motors shall be equipped with thennal switches attached to or imbedded in the motor windings and connected in series. These thermal switches shall be used in conjunction with external thermal overload protection and shall be connected to the control panel. One switch shall be provided per stator phase. The tripping of at least one switch shall shut down the motor and activate an alarm. The temperature switches shall automatically reset once the stator temperature returns to normal. J. Cables: Pump motor cables shall be type SOW -A, SOW, or MSHA as required. Cable sizing shall conform to NEC, ICEA, and CSA specifications. Cable length shall be sufficient for the mixer installation shown on the Drawings. K. Paint: All exposed hardware shall be of 304 stainless steel. All surfaces coming into contact with mixing liquid other than stainless steel shall be protected by a high grade epoxy paint, Tnemec "Series 69n or equal, Mils DFT. 2.3 ACCESSORIES FOR SCUM MIXERS A. Scum Mixer Connection: I. Scum mixer shall be mounted on the same guide rails as scum pump, as indicated on the Drawings. B. Mixer Lifting: Provide grab-link system, with short length of stainless steel chain, nylon cord, and link attachment device. C. Power and Control Cable Holder: L stainless steel, with mounting bracket. 2. Provide grip holders for mixer and control cables. 3. Cables shall be easily adjusted to mixing level without splices. 4. Provide power and control cables which are sealed at the motor and continuous from the motor to the panel or intermediate waterproof junction box for removing submersible mixer for maintenance, as indicated on the Drawings

23 2.4 SPARE PARTS A. The following spare parts shall be provided: 1. One lower (outer) mechanical seal assembly for each model mixer furnished. 2.5 MIXER PROTECTION SYSTEM: Furnished by mixer manufacturer. A. Furnish a complete mixer monitoring and protection system consisting of a intrinsically safe solid state monitoring module to be installed in the motor starter cubicle and independent probes integral to the mixer/motor, as specified herein, wired to a sealed cable entry terminal box for connection of submersible control cables. B. Monitoring unit (or multiple such) shall be a solid~state module designed for mounting within the motor starter cubicle or as indicated on the Drawings. Monitoring unit shall employ conventional logic and noise isolated electronics. Monitoring unit shall accept inputs from the sensors (seal leakage, motor over temperature, motor auto-megger) specified and shall output independent contacts which close to alarm each condition, or separate independent output terminals suitable for direct connection to interposing relays for alarm contact development. Provide a separate N.C. alarm contact, rated at 120V, 5A inductive, which opens on any failure. The monitoring unit shall accept separate isolated N.O. contacts which close to indicate mixer running and to reset after mixer trip. 2.6 ELECTRICAL EQUIPMENT AND CONTROLS A. Conform to NEC, NEMA, IEEE and DIVISION 16 on all electrical equipment and controls. B. Refer to DIVISION 16 for electrical control panel, motor starters, and mixer controls. PART 3 EXECUTION 3.1 INSTALLATION: All Work shall conform to the Drawings, the manufacturer's recommendations, and the requirements of DIVISION 1. A. Attach guide rails, and make any necessary piping connections. B. Make all electrical and control connections, in accordance with DIVISION 16. C. Provide a complete unit with all materials, components and adjustments as required for successful operation. 3.2 START-UP AND TESTING A. Provide all necessary lubrication for initial start-up, testing and as required for final acceptance. B. Installation, start-up and testing of all equipment and associated construction shall conform to manufacturer's recommendations. 3.2 ON-SITE PERFORMANCE TESTS A. Conducted by mixer manufacturer's authorized representative in presence of Contractor and Engineer. B. Equipment Tests: 1. Check performance of all components as a functioning unit. 2. Check alignment of each unit (as applicable). SKW Project # R January 20 13

24 3. Confirm proper rotation of propeller. C. Operational Tests: 1. Conduct such operational tests as necessary to determine that the performance of equipment and controls is as specified. 2. Tests will generally consist of placing equipment in operation under varying conditions and verifying performance. a. Test all control sequences and functions. b. Perform complete meg-ohm testing. c. Take amperage and voltage readings. D. Make all necessary equipment adjustments and corrective work indicated by tests. Repeat testing as necessary. E. Submit a written test report to General Contractor (with one copy to Engineer) in a letter form stating operations performed and results obtained for each unit. END OF SECTION (See Submersible Mixer Schedule Following) SKW Project # R

25 SUBMERSIBLE MIXER SCHEDULE Location Scum Mixers No. ofunits 1 Rated Total Head, feet - Minimum Capacity (per 1425 mixer w/o shroud), g.p.m. Minimum Shut-Off Head, - feet Operating Head Range, feet - Minimum Efficiency, % - Motor Power 480/3/60 (Volts/Ph/Hz) Minimum - Maximum nameplate, hp Discharge Size, inches - Operating Speed (rpm) 1750 Certified Factory Test Required Yes

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27 SECTION GRIT REMOVAL EQUIPMENT (Add Alternate No. 1) PART! GENERAL 1.1 SUMMARY A. General: The Contractor shall furnish and install the grit removal equipment in accordance with the Drawings and as specified herein. B. Section Includes: The grit removal unit shall be furnished complete with gear motor, gear head, air bell, propeller drive tube, axial flow propeller, grit removal pump, grit classifier, and auxiliary equipment as specified herein. C. Coordination Responsibility: The grit removal equipment manufacturer shall be responsible for ensuring that all equipment, piping, and controls be coordinated through shop drawing submittals and installation to provide a fully operational system. 1.2 RELATED SECTIONS A. Section Submittals B. Section Material and Equipment C. Section Contract Closeout D. Section Starting of Systems E. Division 16 - ELECTRICAL 1.3 REFERENCES: The following publications form a part of these specifications to the extent indicated by references thereto. The revision in effect at the time of the Bid Opening shall be applicable. If these publications conflict with the requirements of this section, the requirements of this section shall govern. A. Anti-Friction Bearing Manufactures Association (AFBMA): 1. Bearing Rating Life B. National Electrical Manufactures Association (NEMA): 1. MG 1 - Motors and Generators 2. ISSI-110- Enclosures C. National Fire Protection Association (NFPA): 1. NFPA 70 -National Electrical Code D. National Electrical Code (NEC): 1. Article Flexible Cords and Cables E. National Safety Council F. American National Standards Institute (ANS[): 1. B Cast-Iron Pipe Flanges and Flanged Fittings SKW Project #20 I R

28 G. American Society for Testing and Materials (ASTM): 1. A-48 ~Gray Iron Castings H. American Iron and Steel [nstitute (AISI) I. Institute of Electrical and Electronics Engineers (IEEE) 1.4 SYSTEM DESCRIPTION A. Design Requirements: 1. The grit removal system will be located at the Headworks Structure. Screened raw wastewater will flow into the vortex grit chamber as indicated on the Drawings. The grit removal equipment shall be capable of removing grit from raw, screened wastewater and transporting the dewatered grit to a storage dumpster for final disposal. 2. No moving parts subject to wear or stoppage shall be below the water surface of the grit basin. A grit transporting system shall be provided to transport the grit from the storage hopper to the dumpster. All drives, lubrication and bearings shall be readily accessible from walkways above the operating water level. 3. Grit chamber hydraulics shall incorporate a spiral or toroidal flow path enhanced by a slow vortex. Grit moving across the bottom of the chamber shall be hydraulically scoured as the propeller blades pass over the moving grit and cause hydraulic currents to lift the organics. The grit scouring intensity shall be adjustable. The grit shall pass from the removal chamber and drop into the grit storage hopper. 4. The flow in the grit chamber shall travel between the inlet and the outlet a minimum of360 degrees around the trap to provide maximum travel of the liquid for effective grit removal. The predictable path taken by the grit shah be designed by the equipment manufacturer to provide maximum travel of the flow entering the trap at maximum conditions, and therefore achieve the most effective grit removal. 5. The grit chamber shall handle all flow rates equal to or less than the specified hydraulic peak flow rate. The influent channel, transporting the wastewater to the grit chamber, shall be of the size and shape shown on the Drawings to assure grit does not settle in the inlet channel and to provide for proper operation of the grit chamber. B. Performance Requirements: The grit removal unit shall operate on the vortex principle and be capable of handing a hydraulic peak flow rate of2.0 mgd per unit. The grit removal chamber shall have minimal headless across the chamber. The minimum removal rates of grit particles shall be as indicated below. No decrease in efficiency will be allowed at flows less than the peak design rate % of the grit greater than 50 mesh in size, 2. 85% of the grit greater than 70 but less than 50 mesh in size, and 3. 65% of the grit greater than 100 but less than 70 mesh in size. C. Service Conditions: Grit removal equipment shall be capable of continuous operation with raw screened wastewater at all flow rates from the minimum to maximum without deposition of grit on the grit chamber floor. Equipment, controls, and accessories shall be designed for operation in the type of installation and environment of the project location as shown on the Drawings. D. Sequence of Operation and Controls: Refer to Division 16 and Electrical Drawings. 1.5 SUBMITTALS: The Contractor shall submit the following items required by this Section in accordance with Section Submittals and Section Contract Closeout. A. Product Data for Review: 1. Manufacturer's dimensional and informational data for the grit removal equipment, controls, and all equipment and materials specified herein. 2. Complete wiring diagrams and schematics for all control systems

29 B. Operation and Maintenance Data: The grit removal equipment supplier shall provide approved Operation and Maintenance Instructions in accordance with Section Contract Closeout. I. Each set of O&M Instructions shall include performance criteria and equipment characteristics. 2. Manuals shall include the required service training information listed above and shall include detailed drawings with detailed parts listing, wiring diagrams and schematics for all components. Operation and maintenance manuals shall be submitted for Engineer's approval. 1.6 QUALITY ASSURANCE A. Factory Tests and Reports: 1. Include all manufacturer's standard factory tests on equipment and material. 2. Submit results of factory tests in accordance with DIVISION MANUFACTURER'S FIELD SERVICES: In accordance with Section Starting of Systems, an authorized representative of the manufacturer shall provide the following: A. Start-up Services: Minimum of one 8-hour day. B. Demonstration and Training: One 8-hour session shall be provided. 1.8 DELIVERY, STORAGE, AND HANDLING A. Delivery, storage, and handling shall conform to Division I requirements. B. Shipment Preparation: Prepare equipment and materials for shipment in a manner to facilitate unloading and handling, and to protect against damage or unnecessary exposure in transit and storage. Include: 1. Crates or suitable packaging materials. 2. Covers and other means to prevent corrosion, moisture damage, mechanical injury and accumulation of dirt in motors, electrical equipment and machinery. 3. Suitable rust-preventative compound on exposed machined surfaces and unpainted iron and steel. 4. Grease packing or oil lubrication in all bearings and similar items. C. Marking: I. Tag or mark each item ofequiprnent or material as identified in the delivery schedule or on Submittals and include complete packing lists and bills of material with each shipment. Each piece or component need not be marked separately provided that all pieces are packed or bundled together and the packages properly tagged and marked. 2. Mark partial deliveries of equipment component parts to identify the equipment, to permit easy accumulation of parts, and to facilitate assembly. 1.9 FACTORY ASSEMBLY A. Grit removal unit shall be completely shop assembled and aligned prior to shipping. B. After completion of the specified factory tests, unit shall be prepared for shipment with the minimum amount of disassembly, and such that no field disassembly or cleaning is required. C. Any components removed for shipping shall be match-marked prior to removal and shipment. D. Prepare surfaces and provide paint system standard for the manufacturer and suitable for the service intended. SKW Project # R

30 PART2 PRODUCTS 2. 1 ACCEPT ABLE MANUFACTURERS A. Manufacturers for the equipment specified in this section shall be selected during the bid phase per the pre~bid approval process as described in the Invitation to Bid. No additions or substitutions will be allowed after the bid opening. 2.2 GENERAL A. The contractor shall furnish and install a complete working grit removal system in accordance with the Drawings and as specified herein. All wetted parts shall be constructed of 3 16 stainless steel. 2.3 GRIT CHAMBER A. General: 1. The grit chamber sha11 be equipped with integral flow control baffles in the inlet and outlet of the main chamber. The flow control baffle shall be designed to direct the inlet flow into the chamber in a manner ensuring the proper vortex flow and to prevent short~circuiting. The outlet shall have a baffle to direct the flow out of the unit, and to act as a "slice weir" to control the water level in the main chamber and in the inlet channel. No additional downstream flow control device shall be required to keep the velocity between 3.5 fps at peak flow and 1.6 fps at minimum flow with a 10: I turn down. The baffles shall be constructed of 3 16 stainless steel. The contractor shall attach the flow control baffle to the concrete structure using 5/8-inch anchor bolts, as shown on the drawings. 2. The flow in the chamber shall travel a full 360 degree rotation through the inlet and outlet, providing maximum travel for effective grit removal. 3. The grit chamber shall handle all flows equal to, or less than, a hydraulic peak flow of9.0 mgd. The influent flume, transporting the liquid waste to the grit chamber, shall be of the size and shape shown on the contract drawings to assure that grit does not settle in the inlet flume and to provide for proper operation of the grit chamber. The effluent flume shall be a free-flowing flume for maintaining proper velocity within the chamber. B. Mechanical Drive: 1. Grit removal unit shall have an axial flow propeller connected by a drive tube through gearing to a 3 phase, 60 Hertz, 480 volt, totally enclosed helical gear motor. The maximum rated horsepower of the motor shall be 1.0 bhp. 2. The drive tube shall be driven by a large, totally enclosed combination spur gear and turntable bearing. The maximum output speed ofthe drive shall be 21 RPM. Pinions and gears shall be high quality steel, machined and hardened for high strength and long wear. Propeller blades shall be tapered, with generously rounded leading edge, to reduce energy consumption and prevent foreign material from fouling the propeller. 3. A pinion mounted on the output shaft of the helical gear motor shall drive a large spur tooth bull gear enclosed in a heavy cast iron case. The spur gear pinion shall be cut from heat-treated steel. The bull gear shall rotate with a minimum 21-inch diameter turntable bearing for durability and stability. The pinion and bull gear shall have a service factor of 5.0 or greater at standard operating speeds. 4. All bearings ofthe drive unit, including the motor, shall have a minimum B-10 bearing life of 50,000 hours, except for the 21-inch diameter turntable bearing supporting the propeller assembly which shall have a minimum B-10 life of 20 years. 5. The bull gearbox shall be specifically designed for this service. It shall have an opening for the 1 0-3/4-inch diameter torque tube driving the propeller. The gearbox shall be sealed and the bottom opening shall have an air bell around the torque tube to prevent water from entering the gearbox in case of flooding. The top of the gearbox shall have a bolted flanged connection for the grit discharge pipe. Clarifier drives, which are modified to meet the higher propeller speed, specifically will not be acceptable. The drive motor shall January

31 have normal starting torque and low starting current. The motor shall not be overloaded beyond the nameplate rating under any normal conditions encountered. C. Grit Storage Hopper: 1. A grit storage hopper with a 60 degree sloped bottom shall be provided below the grit chamber. The maximum diameter and minimum depth of the hopper shall be as indicated on the Drawings or approved by the Engineer. Manufacturer shall supply a floor plate to cover the storage hopper. The plate shall consist of two (2) sections with lifting slots to allow access to the storage area. Attaching this plate as part of the rotating assembly will not be allowed. D. Grit Fluidizer: The grit removal system shall be equipped with grit fluidizing water as a means of fluidizing the accumulated grit in the storage hopper. Plant service water shall be used to expand the grit and generate the release of organics. The grit fluidizer water shall be delivered to the grit hopper via a pipe running to the bottom of the grit hopper as indicated on the drawings. A solenoid valve and a manual ball valve shall be provided for control of fluidizer water flow. The solenoid valve shall be wired to the grit system control panel, and shall open automatically for timed operation. I. Grit fluidizer vanes shall be provided in addition, if recommended by the grit system supplier. The vanes shall be installed near the elevation of the pump suction inlet. The vanes shall be bolted to the propeller drive tube in a helical fashion so as to gently pump the grit upward and keep the grit fluidized at the inlet of the grit pump. The fluidizer vanes shall be fabricated of heavy steel plate and coated with 6-8 mils of epoxy paint. The fluidizer vanes shall be bolted to the drive tube to facilitate easy removal of the drive tube. 2.4 FLOODED SUCTION GRIT PUMP A. The grit system shall be provided with a flooded suction grip pump. The grit pump shall be a 4-inch or 6-inch vertical, close-coupled type with curved 5-vane flow inducer completely out of the flow path between the pump inlet and discharge connection, so that the grit pumped is not required to pass through the impeller. All internal clearances shall provide for the passage of a 4-inch spherical solid to preclude clogging of the pump and suction line. The pump shall be vertical, for easy removal of the motor and impeller, to facilitate maintenance of the suction line by providing a straight path to any potential blockage. B. The pump shall be ofni-hard construction, with Ni-Hard impeller, and especially designed for the use of mechanical seals and vacuum priming. Self-priming type pumps are specifically not acceptable. C. In order to minimize seal wear caused by lineal movement of the shaft, the shaft bearing nearest the pump impeller shall be locked in place so that end play is limited to the clearance within the bearing. To minimize seal wear resulting from shaft deflection caused by the radial thrust of the pump the shaft from the top of the impeller to the lower bearing supporting the impeller shall have a minimum diameter of 1-7/8-inch for a 4-inch pump and inch for a 6-inch pump. The dimension from the lower bearing to the top of the impeller hub shall not exceed 6-inch. D. The bottom bearing of the motor shall be locked in place and designed to handle all thrust loads and the necessary radial load. The upper bearing shall be free to move up and down and, thus, carry only radial load. This movement allows for thermal expansion of the shaft. E. The shaft shall be solid stainless steel through the mechanical seal to eliminate corrosion and abrasive rust particles. Removable shaft sleeves will not be acceptable if the shaft under the sleeve does not meet the specified 1-7/8-inch minimum diameter for a 4-inch pump and inch for a 6-inch pump. Carbon steel shafts are not acceptable

32 F. The impeller shall produce a turbine-like flow pattern within the casing, generating flow. To prevent grit from entering the seal area, all impellers less than full diameter shall be trimmed with the back shroud remaining full diameter so that a minimum clearance from shroud to casing is maintained. Both the end of the shaft and the bore of the impeller shall be tapered to permit easy removal of the impeller from the shaft. G. The pump shall be arranged so that the complete rotating element can easily be removed from the casing without disconnecting the electrical wiring or disassembling the motor, impeller, backhead or seal. H. The pump shall be supported by a heavy base with four (4) legs to provide maximum rigidity and balance. Anchor bolts are not included. For ease of maintenance, an isolation plug valve should be installed on each side of the pump. I. The grit pump shall be capable of delivering 250 gpm against a total dynamic head of 18.5 ft. The maximum allowable speed shall be 1780 rpm. The maximum rated horsepower of the grit pump motor shall be 1 0 bhp. J. The pump motor shall be vertical, solid shaft, TEFC NEMA P-base, squirrel-cage induction-type, suitable for 3-phase, 60cycle, 480 volt electric current. It shall have Class F insulation, but the motor shall have Class B temperature limits. The motor shall have normal starting torque and low starting current, as specified for NEMA Design B characteristics. It shall have a 1.15 service factor. K. The motor-pump shaft shall be centered, in relation to the motor base, within.005-inch. The shaft run-out shall be limited to.003-inch. L. A bearing cap shall be provided to hold the bottom motor bearing in a fixed position. Bearing housings shall be provided with fittings for lubrication as well as purging old lubricant. M. The motor shall be fitted with heavy lifting eyes or lugs, each capable of supporting the entire weight of the pump and motor. N. The grit pump shall meet the following minimum requirements: Shaft through seal: Lower bearing to impeller distance: Shaft run-out: Shaft end play: Shaft to motor base: Impeller to shaft fit: Impeller Type: Material: Shroud: Seal housing: Low pressure priming source: Fronthead to casing: Backhead & motor adaptor: Upper bearing: Lower bearing: Motor insulation: Motor temperature rise: Motor service factor: 1-7 /8-inch Diameter, Solid Stainless Steel ( 4-inch Pump) 12-1/8-inch Diameter, Solid Stainless Steel (6-inch Pump) 6-inch Maximum inch Maximum Limited to bearing shake inch Maximum Tapered Recessed 5-Vane Turbo Ni-Hard- High nickel iron Untrimmed- Full diameter Bronze Behind impeller One piece One piece Axially free Locked in place Class F Class B

33 0. Pumps will only be considered if all ofthe above requirements are met as a minimum. These requirements are specified for long service life and ease of operator maintenance. Deviations from the grit pump specifications may be cause for rejection. 2.5 GRIT CON CENTRA TOR (Required with hopper type grit classifier) A. A 250 gpm second stage grit concentrator shall be provided as shown on the drawings for secondary treatment of organics and secondary grit dewatering. The grit concentrator shall operate on the constant rate vortex principle. Design shall be such that a small volume of water and the grit will discharge at the bottom for final dewatering and ultimate disposal of the grit. B. As a minimum, 93 to 94 percent of the water pumped to the grit concentrator and 95 to 96 percent of the residual organic material shall flow out the top and be returned to the inlet channel to the grit chamber. The unit shall be capable of intermittent operation with minimal variation in removal efficiency. There shall be less than 5% putrescible material in the recovered grit from the underflow. C. The grit concentrator shall be constructed ofni~hard, with a minimum thickness of 1/2-inch in high wear areas. Inlet and outlet connections shall be as shown on the Drawings. The grit concentrator shall be provided by the manufacturer of the grit chamber, for installation by the contractor. The operating range shall be compatible with the total grit removal system as described herein. 2.6 GRIT CONVEYOR AND SEPARATOR A. The grit screw conveyor shall be constructed of316 stainless steel with an inlet hopper to receive the mixture of water and grit. The hopper shall be equipped with an energy dissipation zone to prevent turbulence in the remaining portion of the hopper. The hopper shall have parallel plates located in the settling zone to improve retention of the fine grit. An overflow weir trough shall be provided to return the water to the system. The conveyor shall be freestanding with support legs to hold the conveyor at an angle of approximately 22 degrees. The discharge shall be 8-inch diameter, plain-end pipe. The drive assembly shall be located at the discharge end. B. The grit screw conveyor shall have an open, 3/16-inch steel V -trough. The screw and conveyor shall have overall dimensions as shown on the drawing. The hopper shall have a 4-inch full-length outlet weir trough to minimize the overflow rate and carryover of the fine grit. The projected separator plate settling area shall be a minimum of 15.1 square feet. C. The screw shall run on anti-friction bearings at the outlet end, and a bronze bushing at the inlet end. The inlet end shaft bushing shall be capable of being greased. The inlet end shall have two 2-inch drains. Clearance between the legs and the discharge outlet shall be as shown on the drawing. D. The drive to the conveyor shall be a belt-driven, shaft-mounted helical gear reducer. The motor shall be 1 HP, TEFC, 3-phase, 60 Hertz, 460 volt. The screw speed shall be 9 rpm. The drive shall be mounted on a plate at the discharge end and the plate shall be bolted to the flanges on the trough. E. An expanded metal-flattened mesh cover shall be provided over the hopper and trough openings. The 30-inch x 60-inch opening over the hopper shall not be covered. 2.7 ELECTRICAL EQUIPMENT AND CONTROLS A. Refer to Electrical Drawings and Division 16. B. Electrical control equipment shall be located in the Headworks electrical room as shown on the Drawings. SKW Project # R ]

34 2.8 CORROSION PROTECTION A. B. Steel Preparation: 1. All carbon steel surfaces shall be factory blasted with steel grit to remove rust, mill scale, weld slag, etc. All weld spatter and surface roughness shall be removed by grinding. Surface preparation shall comply with SSPC-SP6 specifications. Immediately following cleaning, a single 3-mil dry film thickness of epoxy primer (Tnemec "Series 37H ChemPrime HS" or equal) shall be factory applied prior to shipment. 2. Stainless steel, aluminum and other corrosion resistant surfaces shall not be coated. Carbon steel surfaces not otherwise protected shall be coated with a suitable non-hardening rust preventative compound. Auxiliary components, such as the grit pump, gear motor, etc., shall be furnished with the original manufacturer's coating. Touch up and Finish coating: 1. Final field touch-up and finish coating of primed surfaces, shall be provided under Section PART3 EXECUTION 3.1 INSTALLATION: All Work shall conform to manufacturer's recommendations and the requirements of Division 1. A. Make all electrical and control connections. B. Provide all necessary lubrication for initial start-up, and testing as required for final acceptance. C. Provide a complete system with all materials, components and adjustments as required for successful operation. D. Installation, start-up and testing of all equipment and associated construction shall conform to manufacturer's recommendations. E. Install pipe and pipe appurtenance supports to minimize stresses being placed on equipment flanges. 3.2 ON-SITE PERFORMANCE TESTS A. Shall be conducted by grit removal system supplier in presence of Contractor and Engineer. B. Equipment Tests: 1. Check performance of all components as a functioning unit. 2. Check alignment of unit. C. Operational Tests: 1. Conduct such operational tests as necessary to determine that the performance of equipment and controls is as specified. 2. Tests will generally consist of placing equipment in operation under varying conditions and verifying performance. a. Provide portable ultrasonic or magnetic flow meters to verify flow rates, or use facility Parshall flume. Equipment shall be tested under all normal operating conditions. b. Conduct tests to determine the amount of grit in the influent flow and the percent removal. c. Test all control sequences and functions. SKW Project # R January 20 13

35 D. Make all necessary equipment adjustments and corrective work indicated by tests. Repeat testing as necessary. E. Submit a written test report to Contractor (with one copy to Engineer) in a letter form stating operations performed and results obtained for each unit. END OF SECTION

36 THIS PAGE INTENTIONALLY LEFT BLANK SKW Project # ?R

37 SECTION MECHANICALLY CLEANED BAR SCREEN PART 1 GENERAL 1.1 SUMMARY A. Contractor shall provide one (I) mechanically cleaned bar screen unit and one ( 1) screenings auger and press, located in the Headworks Building. The bar screens, screenings auger, and press shall be factory assembled units consisting of a continuous screening, conveying, washing, de-watering, and compacting systems for the separation, conveyance, washing, de-watering, and compaction of wastewater screenings from a wastewater flow channel. B. Equipment furnished and installed under this section shall be fabricated, assembled, erected and placed in proper operating condition, for a complete operating system in full conformity with the Drawings, specifications, and instructions and recommendations of the equipment manufacturer, unless exceptions are noted by the Engineer. 1.2 RELATED SECTIONS A. Section Submittals B. Section Material and Equipment C. Section Contract Closeout D. Section Starting of Systems E. Division 16 - ELECTRICAL 1.3 REFERENCES: The following publications form a part of these specifications to the extent indicated by references thereto. The revision in effect at the time of the Bid Opening shall be applicable. If these publications conflict with the requirements of this section, the section requirements shall govern. A. National Electrical Manufacturer's Association (NEMA). B. American Society for Testing Materials (ASTM). C. American Gear Manufacturer's Association (AGMA). 1.4 SYSTEM DESCRIPTION A. Design Requirements: 1. The front cleaning, front return link driven mechanically cleaned bar screen assembly shall be suitable for installation and operation in a channel measuring 2 ft wide and 5 ft deep, as measured from the nominal elevation of the channel bottom one channel width behind its base. The angle of inclination shall be as recommended by the screen manufacturer. 2. The opening from which the unit discharges screenings from its enclosure shall be at least 4.7 ft. above the elevation of the top ofthe ground floor of the Headworks building. This is the available clearance for the compactor to collect the debris. 3. The total vertical discharge height of the screen, as measured from its base (bottom of channel) to the screenings discharge point shall be approximately I 0 ft. 4. The screen shall be capable of passing a maximum of3.25 mgd of wastewater with a downstream water level of 1.33 ft. based on a nominal unit width of2 ft. The loss of head at

38 the maximum flow of clean water shall not exceed 13 inches ofwater. The head loss calculation is based on assumption of a clean screen, clean water and steady state flow. 5. The screen shall be capable of presenting a clean filtration surface to the oncoming liquid stream at all times during continuous operation. It shall be capable of intermittent operation in order to form a mat of material to provide maximum trash removal. 6. In order to ensure that the maximum quantity of trash, captured by the screen can be transported out of the channel and into the waiting receptacle, the screen and press must be capable of handling the maximum amount of 18 cu. ft. per hr. B. Performance Requirements: 1. The screen shall be capable of operation with the criteria below. Unless otherwise stated, all flow rates are for wastewater containing typical quantities of solids: a. Maximum solid sphere diameter passing screen, inches 0.25 b. Average daily flow, mgd 0.69 c. Average influent suspended solids, mg/1 250 d. Peak flow through screen, mgd 3.25 e. Upstream water depth at peak flow, feet 2.39 f. Maximum downstream water depth, feet 1.33 g. Maximum clean water headloss at clean water flow of3.25 mgd and maximum downstream water depth, inches 13 h. Minimum height of discharge opening above top of floor, feet The screenings press shall perform as follows: a. Dry solids from compactor b. Reduction in volume of discharged materials C. Sequence of Operation: Refer to Electrical Drawings. 60% by wt. 80% 1.5 SUBMITTALS: The Contractor shall submit the following items in accordance with Section Submittals: A. Product Data for Review: Complete data on materials, dimensions and installation instructions, including but not limited to the following: 1. General Arrangement drawings that illustrate the layout of the equipment, equipment weight, principal dimensions with related verifications required for installation including anchorage locations. Other related data including descriptive literature, Electrical Control Drawings, Catalog Cut Sheets for individual components and Drive Motor Data. See Appendix for quantity required. 2. A list of recommended Spare Parts including any Special Tools required for routine maintenance of the equipment shall be provided. See Appendix for any custom spare parts required. 1.6 MANUFACTURER'S FIELD SERVICES: In accordance with Section Starting of Systems, an authorized representative of the manufacturer shall provide the following: A. Start-up Services: Minimum of one 8-hour session. B. Demonstration and Training: One 8-hour session shall be provided. 1.7 OPERATIONS AND MAJNTENANCE INSTRUCTIONS: Submit in accordance with Section Contract Closeout

39 1.8 QUALITY ASSURANCE A. Manufacturer Qualifications: To assure unity of responsibility, the bar screen shall be furnished and/or coordinated by a single manufacturer who is fully experienced, reputable, and qualified in the manufacture of the equipment to be furnished. The equipment shall be designed, constructed and installed in accordance with the best practices and methods. B. All equipment furnished under this specification shall be new and unused, and shall be the standard product of the manufacturer. A. The screen manufacturer shall have a minimum of 5 years of design and manufacturing experience with bar screening units. 1.9 PRODUCT HANDLING A. In accordance with Section Materials and Equipment, all parts shall be properly protected so that no damage or deterioration wiu occur during a prolonged delay from the time of shipment until installation is completed and the units and equipment are ready for operation. On-site precautions shall be taken by the Contractor to insure adequate protection during storage WARRANTY A. B. Manufacturer shall provide a written one year standard warranty from the date ofuse of the mechanically cleaned bar screen equipment to guarantee that there shall be no defects in material or workmanship in any item supplied. Manufacturer shall warrant for the period of 5 years all rotating parts of the Mechanically Cleaned Bar Screen including the gear motor, bearing, drive head, and the link system including the links, castings, pins and retaining rings. Manufacturer warrants that these components shall be replaced if damaged or defective in the normal use of the equipment. PART2 PRODUCTS 2.1 ACCEPT ABLE MANUFACTURERS A. Manufacturers for the equipment specified in this section shall be selected during the bid phase per the pre-bid approval process as described in the Invitation to Bid. No additions or substitutions will be allowed after the bid opening. 2.2 BASIS OF DESIGN A. The automatic bar screen will be designed to positively clean and remove debris up to 3 inches in diameter from the influent stream by means of high impact plastic filter elements designed to retain and elevate debris to the discharge point of the unit where the rotating brush assembly cleans the elements. B. The mechanically cleaned bar screen shall run continuously without an operator. C. The screen shall be capable of presenting a clean filtration surface to the influent stream at a11 times during continuous operation

40 2.3 COMPONENTS A. Frame Assembly 1. The frame of the unit, which is stationary, shall be constructed from type 304 stainless steel with a thickness of 3/16 inch. It supports and locates all of the operating components. The unit shall rest at the bottom of the channel, and be anchored at the operating floor elevation. No mechanical mounting or fastening of the unit frame is required to the sidewalls or bottom of the channel. 2. The "A" frame unit shall be supported at the operating floor elevation by support legs constructed from type 304 stainless steel. The legs shall be designed to allow the unit to pivot the screen out of the channel without dewatering (e.g. for bypass purposes). Routine service of the unit is possible with the screen in the channel 3. Guide rails shall be mounted to each side on the inside surface of the frame to direct the filter belt during its ascension out of the channel. The guide rails shall be 1/2 inch thick and will be constructed from type 304 stainless steel. 4. At the top of the screen, circular chain guides shall gently direct the filter belt from its ascending path out of the channel towards the drive sprockets. These circular guides shall be constructed from type 304 stainless steel and shall be welded to a type 304 stainless steel shaft. In order to reduce the wear on both the chain and chain guides, the shaft shall be secured to bearings on each side of the frame and free to rotate. 5. Chain guides shall also be provided to direct the filter belt from the drive sprockets to the descending path into the channel. These fixed rails shall be constructed of type 304 stainless steel and shall be 5/8 inch thick. 6. Lower return guides shall be provided at the base of the screen to direct the filter belt during its 180-degree turn from the descending to ascending paths. The lower guide rails shall be constructed from I /2-inch thick type 304 stainless steel and shall be fixed in place as low as possible in the frame to optimize the submerged screen area. No submerged bearing or rotating guides are used that will require routine maintenance or that may become fouled by trash and debris. 7. Neoprene rubber seals with type 304 stainless steel backing plates shall be mounted along the upstream edges of the frame to seal the outer edge of the frame against the channel wall, and the area between the frame and filter belt side plates. 8. The bottom of the unit shall be sealed with two rows of nylon brushes, which allow the elements to pass through, but prevents trash from passing beneath the filter elements, ensuring capture of all solids and trash by the filter belt. 9. All shaft bearings are mounted externally to the side frame for ease of access and maintenance. 10. The rear portion of the screen shall be equipped with covers to protect operators from contact with moving parts and minimize misting and dripping. Al1 enclosures shall be removable. There shall be a hinged section for access to the screen and rotating brush assembly for periodic maintenance. The covers shall be fabricated from 14 gauge type 304 stainless steel. 11. Lifting cables shall be provided for each side ofthe screen to assist in pivoting the screen out of the channel. Lifting cables shall extend from the lifting points at the base of the unit and extend to the top of the channel where they shall be secured to the screen. Lifting cables shall be composed of3/8 inch diameter type 316 stainless steel wire rope. B. Filter Belt/Screen Assembly 1. The screen shall provide dual filtration of all materials in order to minimize compaction of captured debris and minimize the head loss through the screen. This shall be accomplished by recessing the horizontal fine filtration opening in the face of the screen. The coarse horizontal openings formed by the upper or forward shank/arm of the elements shall be 6 millimeters and shall be the first opening the flow stream contacts as it passes through the screen. The lower or recessed shank/arm of the elements shall create a two dimensional grid which limits the maximum vertical opening to 6 millimeters and the fine horizontal opening of 6 millimeters. The elements are arranged in a staggered fashion to form an