From the outside, an elastomeric expansion joint looks to simply be made out of molded rubber. Part of the reason expansion joints are used in such a wide variety of applications is that the interior construction of a joint can be custom-designed to handle your specific application - materials of construction will depend on size, temperature, application, media, pressure (S.T.A.M.P.).
Tube
Garlock Style 215 Expansion Joints are PTFE concentric spool-type flexible couplings that are designed to reduce noise and compensate for expansion, contraction, and minor piping misalignment in chemical processing, air conditioning, and heating systems.
The complete assembly includes a fluorocarbon resin PTFE body, electroless nickle-plated ductile iron flanges, polyethylene-covered restriction zinc plated bolts, and stainless steel corrosion-resistant reinforcing rings.
Primary Metals
South American manufacturer of flat and long steel products
Construction of two new facilities including a hot rolling mill.
The plant was in need of expansion joints that could handle chemicals on their pickling lines. Pickling is a metal surface treatment used to remove impurities, such as stains, inorganic contaminants, rust or scale from ferrous metals. A solution called pickle liquor, which contains strong acids, is used to remove the surface impurities. It is commonly used to clean steel in various steel making processes. The line required an expansion joint with a PTFE tube to handle the pickle liquor which included hydrochloric and sulfuric acid, but a very short overall length for installation.
The ABRA-LINE™ family of products was developed for highly abrasive applications typically found in the power generation, fertilizer, mining and chemical industries. These may include flue gas desulphurization systems, phosphate mining, dry bulk power transfer systems, tailings and slurry applications. Our proprietary urethane formula was designed to reduce wear and extend
service life.
Style 404 Expansion Joints are specially designed for full vacuum abrasive service applications. The tube material is a proprietary urethane formulation. Style 404 can be constructed as a single or multiple arch design. It can also connect pipe flanges in concentric or eccentric tapers, to join piping of unequal diameters.
Industry
Chemical Processing
Observation
A stainless hosing was used and would continuously fail due to abrasion on the leading edge of the hose. The hosing would last for 3 to 6 months before replacement.
Gallagher recently released its Expansion Joint Design Guide, now available for download on our site. This design guide takes an in-depth look at elastomeric, metal, and flue duct expansion joints. The excerpt below is a section of our Expansion Joint Design Guide focusing on types of elastomeric joints and types of pipe movement. To download the entire guide, visit our Resources Page, or click on the image to the right.
The basic purpose of an expansion joint is to absorb movement and vibration in a rigid piping system, being built to expand, contract, and adjust without straining or breaking the piping or ducting on either side. They are specially engineered to handle movements due to thermal expansion, vibrations of pumps, and misalignments due to installation tolerances, while also being resistant to the process conditions and the external influences of the application.
An expansion joint can relieve stress in piping systems and prevent flange gaskets from being crushed. But which expansion joint is best for your specific application? Let us first describe the two types of expansion joints:
Rubber — a flexible connector fabricated of natural and/or synthetic elastomers and fabric and, if necessary, internal metallic reinforcements designed to provide stress relief in piping systems due to thermal movements and mechanical vibration.
Metal — a flexible element (bellows) constructed of relatively thin gauge material (generally stainless steel) designed to absorb mechanical and thermal movements expected in service.
Temperature
Rubber joints with standard construction and materials have an upper range to 230°F. Most manufacturers, however, can offer special constructions up to 400°F. Metal expansion joints do offer a far greater range, from -420°F to +1800°F. However, working pressures are reduced at elevated temperatures.