Gilflo ILVA flowmeters for steam, liquids and gases

Gilflo ILVA flowmeters for steam, liquids and gases

The Gilflo in-line variable area (ILVA) flowmeter... is a revolutionary development of the well established family of Gilflo flowmeters that has been used in industrial flowmetering applications for more than 3 years. Using the same unique operating principle but incorporating a number of significant design changes, the Gilflo ILVA flowmeter is perfectly suited for use with most industrial fluids including steam and gases. A comprehensive range of associated sensors and electronic instrumentation is available to compliment the Gilflo ILVA flowmeter range and make it one of the most adaptable flowmeters available. Why install flowmeters? The main justifications for installing flowmeters in any industrial plant are: Product quality: By providing management information, they enable a plant to be operated at peak efficiency thus ensuring product quality is maintained in the most cost effective way. Direct cost control: They can be used to cost raw materials or energy sources (such as compressed air) directly. How the Gilflo ILVA flowmeter works In common with other differential pressure flowmeters such as orifice plates and venturi meters, the Gilflo ILVA flowmeter primary element uses the theorem for the conservation of energy in fluid flow through a pipe. It operates on the well established spring loaded variable area (SLVA) principle where the area of an annular orifice is continuously varied by a moving cone. A centrally positioned cone is free to move axially against the resistance of a precision compression spring. This produces a variable differential pressure across the annular orifice which is sensed by a transmitter connected to integral tappings on the flowmeter body. The pressure difference can then be used to derive an instantaneous rate of flow based on Bernoulli s Theorem. p The unique design of the Gilflo ILVA flowmeter greatly expands the capabilities of the differential pressure flow measurement. The key to the unique performance of the Gilflo ILVA flowmeter lies in the design of the orifice and cone to minimise upstream velocity profile effects and at the same time provide an exceptionally high turndown flowmeter based on practically achievable line velocities. Installation benefits The correct installation of any type of flowmeter is of prime importance if the manufacturer's claims for accuracy and repeatability are to be achieved in practice. All types of flowmeter require a certain number of straight, uninterrupted lengths of meter size pipework upstream and downstream of the point of installation. D Gilflo ILVA 6 D 3 D In real life, there are often space constraints that severely restrict where and how a flowmeter can be installed. It is therefore very important to look carefully at where the flowmeter is to be fitted as early as possible. The unique wafer design of the Gilflo ILVA flowmeter means that its installed length is much shorter than almost any other flowmeter. A Gilflo ILVA flowmeter can often be fitted into lines which were never designed to accept flowmeters. Gilflo ILVA flowmeter 6 diameters Turbine Vortex Orifice plate up to 2 diameters up to 3 diameters up to 3 diameters 1 2 3 2 Number of upstream diameters of straight pipe

The importance of turndown DN15 Gilflo ILVA flowmeter 5 bar g saturated steam Vortex meter Benefit of large turndown at low flows Gilflo ILVA flowmeter.6 1 2 2.8 3 Minimum velocity m/s To ensure that the flow information gathered is accurate whatever the process conditions or demand, it is essential that a flowmeter is capable of meeting its specification over the full operating range from low standing or weekend loads, right up to the maximum demand of the process. As actual demands are often unknown or may vary widely, a flowmeter should have the largest turndown possible based on practical flow conditions. Great care should be taken that claims for turndown are based on realistic flow velocities. For instance, steam systems should be sized on a maximum flow velocity of about 35 m / s... higher velocities will possibly cause erosion and noise problems in the system. Turndown ratios with flow velocities limited to 35 m/s Gilflo ILVA flowmeter 1:1 Turbine typically 1:1 Vortex up to 15:1 depending on operating conditions Orifice 4:1 2 4 6 8 1 Flowrate kg / h 1 75 5 25 Threshold at 4:1 turndown Actual flowrate Cumulative error Orifice plate 1 2 3 4 5 6 7 8 Hours elapsed Flowrate below minimum of 25 kg/h (i.e. 1 kg / h 4) 2 1 7 1 5 1 5 Cumulative error kg This graph shows a typical demand curve for a distributed steam system with a high start-up load and variable demand through the day. An orifice plate meter with a 4:1 turndown is sized on the peak load of 1 kg / h. Any flowrates below 25 kg / h are 'lost' or, at best recorded with a significant error. In this case 1 7 kg have been 'lost'. The Gilflo ILVA flowmeter, with its 1:1 turndown eliminates this type or error. Density compensation It is rare for the pressure in a steam system to remain absolutely constant. Unless this variation is taken into account, flow measurement errors will occur. The automatic density compensation options completely eliminate these errors and allow accurate metering whatever the steam pressure. This is shown in the adjacent diagram. Flowrate kg/ h 1 8 6 4 2 Actual flowrate Actual system pressure Cumulative error 1 2 3 4 5 6 7 8 Hours elapsed In the example above, a simple non-compensated flowmeter is set for 6 bar g. The actual pressure in the system varies through the day and unless this is allowed for, by the end of the day, very significant errors can arise. This is typical of many steam systems. 1 8 6 4 2 Pressure bar g 3 5 3 2 5 2 1 5 1 5 Cumulative error kg 3

Gilflo ILVA flowmeters... proven technology in a new package. Thirty years experience and over 1 installations worldwide has firmly established the technology that gives Gilflo flowmeters their unequalled turndown and ultra compact installation. Now the Gilflo ILVA flowmeters uses this wealth of experience in a wafer design to give even lower cost of ownership. Designed and supported by Spirax Sarco s worldwide expertise, the Gilflo ILVA flowmeter is the logical choice. Range availability Sizes DN5 (2") to DN2 (8") All stainless steel 316L body construction Pressure rating to match flange specifications Temperatures up to 45 C Applications Cost metering for energy management Custody transfer Process and control applications Boiler load control Flow direction Commonly metered fluids Saturated steam Superheated steam Condensate Natural gas Nitrogen Carbon dioxide Compressed air Ethylene Fuel oil 4

User benefits Suitable for most industrial fluids. Excellent turndown, up to 1:1. High pipeline unit accuracy, ±1% of reading. All stainless steel construction. Alignment webs for easy installation. Precision cone. Wafer design fits between customer flanges. Over-range stop prevents damage from surges or excessive flows. Ultra compact installation, requires only six pipe diameters upstream and three downstream. Wafer design for easy installation. No expensive line size changes required to achieve low flow performance. Intrinsically safe for use in hazardous areas. Reliability proven over 3 years experience. Designed and manufactured by Spirax Sarco - an ISO 91:2 approved company. Precision heavy duty nickel cobalt alloy spring operates up to 45 C without creep. Pressure tappings built into the flowmeter body for easy installation. Gilflo calibration rig, Spirax Sarco, Cheltenham, England 5

Gilflo ILVA flowmeters... system configurations and associated equipment EL223 temperature transmitter Gilflo ILVA M8 (steam) and M25G (gas) flow computers provide complete information on flow, pressure and temperature. Full density compensation. EL26 pressure transmitter F5C isolation valves M61 differential pressure transmitter Linearisation of Gilflo signal. Wall or panel mounting. Easy to read display. Alarm facilities for fluid flow, pressure and temperature. 4 independent timers. ok M8 series flow computer Analogue and pulse outputs available as standard. M8 Gilflo ILVA M64 steam mass flow transmitter provides density compensated 4-2 ma output. Linearisation of Gilflo signal. F5C isolation valves M64 Steam mass flow transmitter Ideal for applications where density compensation is essential. Suitable for use up to 74 bar g saturated steam. HART 5.2 in-built. Optional local display. Intrinsically safe pipeline unit and mass flow transmitter. M75 display unit Gilflo ILVA M75 display unit provides local display of total flow and rate of flow. Suitable for steam and most industrial fluids and gases. F5C isolation valves Ideal for applications where fluid density is constant. 6 M75 display unit M61 differential pressure transmitter Note: The illustrations above are schematic only. Refer to Installation and Maintenance Instructions for further details. User configurable. Linearisation of Gilflo signal. Retransmission options of rate and / or total flow available. Bright, easy to read display. Panel mounting as standard.

Calibration of Gilflo ILVA flowmeters All Gilflo ILVA flowmeters are calibrated on a high accuracy flow facility at Spirax Sarco s manufacturing plant in Cheltenham, England. Designed and built by Spirax Sarco engineers in conjunction with UK National Engineering Laboratories, it ensures that every flowmeter meets the highest possible standard of accuracy. Some basic features of the flow facility are: Facility size capability: DN5 to DN3. Reference methods: gravimetric and transfer standard electromagnetic meters. Flow capacity: up to 19 litres/min water. Pipework: all 316L stainless steel with upstream and downstream pipework straight runs in excess of recommended lengths. Flowmeter location: clamping arrangements ensure flowmeters are concentric to pipework to ensure accurate calibration. Fully automatic data collection: archiving of all flow data electronically for future reference / recalibration. Calibration documentation: full calibration documentation is available with every flowmeter. Sizing and selection of a Gilflo ILVA flowmeter It is important to select the correct size of Gilflo ILVA flowmeter for a particular application. First principles can be used as follows, determine the equivalent water flowrate (litres/min) based on the maximum anticipated actual flow, then select the Gilflo ILVA best suited to the application using the tables below. Alternatively consult Spirax Sarco. Equivalent water flowrate Liquids = Gases and steam actual flow conditions Mass flow units = q m q m SG Volumetric units = Q L SG 1 D = Q F D F F 1 Gases q m = = Q D S P S x S T F standard x D S x P F T x S 1 P F T S conditions 1 P S T F Using the value of as determined above, select the correct Gilflo flowmeter from the table below: Where: = Equivalent water flowrate (litres/min) q m = Mass flowrate (kg / min) Q L = Maximum liquid flowrate (litres / min) Q S = Maximum gas flowrate at standard conditions (litres/min) Q F = Maximum gas flowrate at actual flow conditions (litres/min) SG = Specific gravity D S = Density of gas at standard conditions (kg/m 3 ) D F = Density of gas at actual flow conditions (kg/m 3 ) P S = Standard pressure = 1.13 bar a = 1.33 kg / cm 2 a = 14.7 psi a P F = Actual flow pressure in same absolute units as P S T S = Standard temperature (K) = C + 273 T F = Actual flow temperature (K) = C + 273 Table of Flowmeter type Maximum Maximum P litres / minute Wg DN5 149 2 DN8 585 2 DN1 1 2 2 DN15 2 9 2 DN2 5 7 2 From the table, it can be seen that a DN5 Gilflo ILVA flowmeter would be suitable for this application. Note: 1 m³/h = 16.667 litres/ min. Example: Determine which Gilflo pipeline unit is required to measure the flow of compressed air when: 1: The estimated maximum flowrate = 5 s m³/h at 7 bar g and 2 C Note: Standard conditions = 1.13 bar a, C giving a standard density of 1.29 kg/m³ D 2: Calculate from: = Q S P S x S T x F 1 P F T S Q 1.29 x 1.13 x 293 E = (5 x 16.667) x 1 8.13 273 = 11 litres/min. Sizing the Gilflo ILVA flowmeter for saturated steam - capacities kg/h Steam pressure bar g 1 3 5 7 1 12 15 2 25 3 4 DN5 Maximum flow 3 416 53 577 671 727 84 918 1 2 1 113 1 283 Minimum flow 3 4 5 6 7 7 8 9 1 11 13 DN8 Maximum flow 1 179 1 632 1 976 2 264 2 635 2 855 3 156 3 63 4 3 4 371 5 39 Minimum flow 12 16 2 23 26 29 32 36 4 44 5 Maximum flow 2 47 3 43 4 165 4 78 5 575 6 5 6 7 7 66 8 535 9 33 1 8 DN1 Minimum flow 25 34 42 48 56 61 67 77 85 93 18 Maximum flow 5 847 8 92 9 795 11 224 13 62 14 152 15 643 17 859 19 843 21 667 24 98 DN15 Minimum flow 58 81 98 112 131 142 156 179 198 217 25 Maximum flow 11 492 15 95 19 252 22 61 25 674 27 816 3 746 35 11 39 2 45 587 49 98 DN2 Minimum flow 115 159 193 221 257 278 37 351 39 426 491 Note: Maximum flowrates are calculated at a differential pressure across the Gilflo ILVA pipeline unit of 498 mbar (2" H2). Minimum measurable flowrate is 1% of maximum. 7

Gilflo spring design The design and manufacture of the spring in the Gilflo ILVA flowmeter is fundamental to its accuracy and long term performance. Made from 'aerospace' alloy Inconel X75 which is widely used in jet engine turbine components due to its exceptional high temperature performance. During manufacture, all springs are age hardened at 65 C for 4 hours. All springs are 'hot set' at 46 C after manufacture to eliminate any possibility of relaxation at high temperatures. Design stress levels range from 11% to 3% UTS... most springs are designed to stress levels of around 6%. In service, all Gilflo ILVA flowmeters incorporate over-range stops to prevent over stressing the spring in overload conditions. Many thousands of installations have proved the integrity of the design and manufacture of the spring. Specification Operating principle Limiting conditions Sizes available Spring loaded variable area with differential pressure output proportional to rate of flow. To ANSI 6 (carbon steel) pressure / temperature envelope. DN5, DN8, DN1, DN15 and DN2 EN 192 PN16, PN25, PN4 BS 1 Table H Flange specifications ANSI B 16.5 Class 15, 3, 6 JIS 2 KS 2 Body and internals: Stainless steel 316L Materials of construction Spring: Inconel X75 Installation Normally horizontal. For vertical (flow downwards) applications, consult Spirax Sarco. When used in conjunction with an M8 series flow computer or M75 display unit or M64 steam Accuracy mass flow transmitter, pipeline unit accuracy is better than ± 1% of actual flow from 5% to 1% of maximum rated flow. For flows from 1% to 5% of maximum rated flow, the pipeline unit accuracy will be better than ±.1% FSD. Repeatability Better than.25%. Unrecovered pressure drop Less than 2 inches water gauge (498 millibar) at maximum flowrate. Dimensions / Weights (approximate in mm and kg) Size A B C D E Weight DN5 35. 63 13 13 17.5 2. DN8 45. 78 16 138 22.5 3.9 DN1 6.5 13 28 162 37.5 8.3 DN15 75. 134 3 218 37.5 14.2 DN2 85. 161 36 273 42.5 23.6 D E Note: Pressure tappings are threaded ¼" NPT. (2 off located at 18 ) In addition to the ILVA range, Spirax Sarco can supply Gilflo flowmeters for special requirements in sizes from DN5 to DN4. These are of flanged, pressure vessel type construction and can be manufactured to meet most international standards construction and inspection. Please consult Spirax Sarco for details. A B Some of the products may not be available in certain markets. C Spirax-Sarco Limited, Charlton House, Cheltenham, Gloucestershire, GL53 8ER UK. Tel: +44 ()1242 521361 Fax: +44 ()1242 573342 E-mail: Enquiries@SpiraxSarco.com Internet: www.spiraxsarco.com Copyright 26 Spirax Sarco is a registered trademark of Spirax-Sarco Limited 8 SB-P337-7 MI Issue 6