Experience advanced designs and superior fabric expansion joint solutions

Transcription

1 Experience advanced designs and superior fabric expansion joint solutions

2 Innovative Solutions to Thermal Growth Problems in Gas Transfer Applications (EJS) has been designing and manufacturing metal and fabric expansion joints since In 1992, we joined forces with LBH International, one of Europe s leading fabric expansion manufacturers to offer what we consider to be the bestengineered fabric expansion joint on the market today. Today, EJS is one of the top U.S. designers and manufactures of quality engineered metal expansion joints. Our engineering department has in house Finite Element Analysis (FEA) capability, including heat transfer and thermal design. LBH continually strives through testing and experience to be at the leading edge of fabric technology. The combination of engineering and experience within the two companies provides our customers with the most advanced and technologically superior fabric expansion joint solutions. The introduction of Fabric Expansion Joints has changed the way engineers solve thermal growth problems in gas transfer applications. Fabric Expansion Joints will normally accommodate large movements over relatively short installation lengths. Their use in large ducting systems in place of metallic units reduces cost and weight, and enables fast, simple replacement. EJS designs Fabric Joints to meet their customers service requirements. We offer a range of Multi-Layer Fabrics for low to high temperature applications; Fluoroelastomers used in power generating and waste water treatment applications and fluoroplastics for desulfurization systems. This Fabric Manual is designed to give engineers an overview of our concepts and provide them with all relevant information required to solve thermal growth problems for a specific application. Our team of engineers at EJS is always ready to help and advise you on applications not covered in this manual. We are proud to say the following companies are just a few we have supplied: Stewart & Stevenson Universal Silencer G.E. Gas Turbines C.F. Braun Fluor Daniel M.W. Kellogg P.G. & E. Kawasaki Heavy Industries Monsanto Chemical Amoco Chemical Diamond Shamrock Foster Wheeler G.A. Technology OxyChem Monsanto Enviro-Chem Pratt-Whitney Columbian Chemicals Jacobs Engineers K.T.I. Fina Oil Vogt-NEM Florida Power & Light San Diego Gas & Electric Pacific Gas & Electric Raytheon Engineers Allied Signal Aerospace Systems Simplot Chemical John Zink Deltak Corporation ABB Alstom Rolls-Royce Ltd. G.E.A. Power Cooling Gas Turbine Exhaust Assembly with liner transition from hot turbine flange to cold silencer ducting. 1

3 APPLICATIONS It is essential that all the relevant parameters and conditions affecting Expansion Joints are taken into account. EJS/LBH have three basic types of Multi-Layer construction to meet the various needs of our customers: Type L for clean air systems: ranging from simple air intake/exhaust on fans and blowers to high temperature air discharge from heaters. Type M for gas with low acid content: used on Gas Turbine Exhaust and less severe flue gas systems. Type R for gas with high acid content: for use in environments where the flue gas contains acids at temperature or acids that can form due to condensation at shut down. Acid barriers are either PTFE impregnated glass cloth or PTFE foil thermally welded to ensure tight seal. EJS Multi-Layer Fabric temperature range is from -58 F and 2,000 F with a standard pressure range of ± 120 W.G. The combined temperature, pressure and media are all decisive factors to be taken into account when selecting the most suitable combination of fabrics. Our standard codes are shown above from L70 to R1100. The sectional view of a standard R700 (shown above) details the EJS engineered approach to Multi-Layer Fabrics. The typical outer layer is silicon coated glass fabric which withstands most environmental conditions. Viton, PVC and Hypalon outer layers are also available. Fabric Expansion Joints MULTI-LAYER FABRIC Field splicing of Multi-Layer Fabric can be readily undertaken without the need for vulcanizing equipment. EJS can supply a filed splice kit with detailed instructions for customer splicing or provide field service personnel. An important difference in the EJS/LBH Multi-Layer Fabric is that we do not rely on an insulation pillow to reduce the temperature in contact with the element. The Multi-Layer Fabric is always designed to withstand the temperature regardless of secondary insulation pillow. Many competitive designs rely on this insulation pillow for primary protection of their element with disastrous results after several temperature cycles. 2

4 Gas Turbine Exhaust Assembly with Viton outer layer material Design of Multi-Layer Elements EJS fabric elements range from single layer type L70 for use on light duty air fans to R1100 for use in continuous 1900 F incinerator service. The design is based on the fabric element s ability to withstand the media temperature. EJS s high temperature element is a stainless steel or inconel wire mesh that gives the unit its shape and ensures that all layers remain tight. Next comes ceramic or glass insulation layers, then the acid barriers (if required), and finally the outer cover to protect the unit from atmospheric conditions. The flange areas have an additional protective layer to prevent damage during bolt up. More than 60 different materials may be selected to ensure the correct design for each customer s specific environment. Multi-Layer Fabrics are offered in three basic styles: Clamp-on, Belt-Type and Flange Type. The five basic style numbers shown on the left meet all positive and negative pressure applications. Movement capabilities depend on system temperature. Thicker sections for higher temperatures have less movement capability. This table enables you to determine the L dimension if the movements are known for all standard types. example: 3/4 axial and 1 lateral for R x 100 = Therefore the largest figure is chosen L.=10 1 x 100 = Note: Movements are current for any Length L 3

5 ELASTOMERIC EJS Elastomeric Expansion Joints provide an effective and durable solution to the problem of handling low to medium temperature gases and associated condensates in hot air and flue gas systems. CSM (Hypalon) CSM (Hypalon) is a chlorosulphonated polyethlene rubber with excellent resistance to oxidation. Joints are suitable for wet and dry chemical service up to 212 F and pressures up to 5 PSIG. The material is color stable and weather resistant but is not suitable for severe operating conditions EPDM EPDM is suitable for wet and dry chemical service at continuous temperatures up to 250 F and pressure up to 7 PSIG. The material is an ethylene propylene diene terpolymer and can resist hot air, non-oily flue gas and extreme weather conditions. EPDM is used in power generation service where it resists attack from acids, flyash deposits and scrubber-treated gases. However, EPDM is not suitable for sustained service where oils, hydrocarbons or concentrated mineral acids are present. EJS includes four standard elastomers with molded section and flat profile. The elastomers can reinforce with fiberglass as required. The units are supplied endless, unless specified by the customers. EJS can provide vulcanizing equipment for use in field spliced units. FKM FKM is Viton B, a fluorocarbon elastomer which has shown exceptional performance in the power generating field since the early 1970 s. The fluoroelastomer combines temperature resistance with fluid resistance, compression-set resistance and resistance and retention of designed hardness. It is suitable for wet and dry service at continuous temperatures up to 400 F (with higher peak values) and pressures up to 7 PSIG. FKM is used extensively in the power generating industry; it withstands acid attack from scrubber treated gases and acidic flue gases and condensates. FKM is unaffected by the sulfur content of coal or oil fuels and is used to seal ducting against high temperature leakage of SO2 and H2S. The elastomer has excellent resistance to weather and ozone attack as well as mineral acids and oils. SI SI has thermal properties comparable to FKM and shows stable mechanical performance over a wide range of temperatures. Silicon rubber is favored by the food-processing industry for two reasons. First, there is no alteration in the flavor of the food. Secondly, it is physiologically acceptable to animal tissue. The material is unaffected by atmospheric exposure and extreme weather conditions and shows no ozone cracking. This material, impregnated into fiberglass cloth, is used for the outer covering of EJS Multi-Layer type fabrics. Units Manufactured from this material can be used in wet or dry service with continuous operating temperatures of 400 F (with higher peak values) and pressure up to 3 PSIG. This material should not be used in SO2 environments. 4

6 Elastomeric Flat and convex profile, Elastomers have continuous design to eliminate splicing or joint in corners. Movements Capability Elastomeric Expansion Joints have an exceptional ability to absorb combination movements resulting from equipment misalignment and thermal expansion. These movements may be linear (in all three planes), angular or torosional. 36 dia. Air Intake Type IV Elastomeric Extension may be increased by precompression. Short term movements up to 40% greater than those shown are possible, but must be approved by EJS engineers. 5

7 FLUOROPLASTIC EJS provides three basic forms of Fluoroplastic Expansion Joints materials, which are designated RST. All are manufactured from similar compounds of PTFE (Polytetrafluoroethylene) and PFA (Perfluoroalkoxy Polymer). These Fluorocarbon Resins are used with a fiberglass weave to give a high strength fabric material on which a film of PTFE is laminated to provide an extra chemical barrier. Th position of the chemical barrier denotes the three basic forms of materials can be further modified for unusual applications, e.g. severe movement conditions or chemical attack from aggressive external and environmental conditions. RST combines a high strength, lightweight material with an ability to resist the chemical attack of sulfur dioxide, sulfuric acid and most other chemicals. It is widely used in the Power Industry on de-sulfurization systems and where fly ash deposits would corrode other materials. RST can operate continuously at 575 F (with higher peak temperatures) while still remaining flexible and strong. Its advantage over Fluorinated Elastoplastics, which are a compounds of PTFE and PFM, is its ability not to degrade at higher temperatures. FKM cannot withstand temperatures above 450 F for long periods of time. In recent years, Fluoroplastics (sometimes referred to as Fluoropolymers) have been replacing FKM (Viton) Elastomeric type expansion joints in more severe applications. Fluoroplastics give longer life at a lower cost. RST can be used in wet or dry service. However, on dry service applications, costs can be reduced using Multi-Layer type shown earlier in the catalog. RST-1502 is the standard material for wet applications. It includes one PTFE (Fluoroplastic) film on the inside to prevent chemical attack of the pressure carrying material. The tensile strength of this material is 1400lbs/in. with a maximum pressure capability of 3.5. PSI. This material is suitable for most applications including the highly corrosive environments on fossil fuel scrubbers. RST-1501 consists of two layers of high strength material with an intermediate chemical barrier of PTFE film. Its tensile strength is increased to 1625 lbs/in. RST-1503 is manufactured from two layers of Fluorinated Elastoplastic with two chemical barriers of PTFE film, one on the inside and one molded between the two layers gives the ultimate protection from chemical attack. Tensile strength is 2000lbs/in. EJS/LBH offers a wide range of materials from which we can manufacture our Fabric Expansion Joint. The best choice of material for a particular application is critical. Our engineers are always ready to help. Please call on EJS at anytime to discuss with our engineers the best choice of materials. 6

8 ENGINEERING Options A) Multi-Layer - Elastomeric - Fluoroplastic B) Insulation Basket - ceramic blanket enclosed in wire mesh or fiberglass C) Shaped attachment flanges D) Various methods of attachment to suit customer ducting E) Flow/Abrasion Liners F) Stiffener Bars A) Accumulation Pillows/Internal Insulation B) Dust Seal S.S. wire mesh rope C) Transition Liners D) Thermally Stable Liners accommodate differential expansion between liner and flange E) Hot to Cold flanges F) Flange Gasket to ensure leak-free operation Rounded corner designs give higher flexibility to the fabric element and prevent corner stress on all layers. EJS corners are formed into the fabric during manufacturing. Elastomeric corners are heat molded to ensure the greatest flexibility. 7

9 ENGINEERING 8

10 Specification Sheet EJS Fabric Expansion Joints EJS offers an extensive range of Fabric Expansion Joints to meet the varied applications that exist in today s industries. The choice of fabric type depends on the severity of the service and application. Temperature and media are the primary considerations when choosing which fabric material to use or specify. Many more questions should be answered before the correct selection can be made. Certain media may become corrosive as they cool to form condensates. Some may affect the fabrics at high temperature and have no effect at a lower temperature. Supplying EJS with as much information as possible is to your advantage. Complete application information enables a correct and long lasting solution. 9