These single expansion joints are custom designed for an internal reactor in a propylene process unit. They are fabricated with Incoloy 800H bellows and A-240 type 304H stainless steel weld ends. The expansion joints range in diameter from 59-7/15″ to 78-8/8″ and are 41-5/16″ long. They were designed for a lateral movement of 0.25″, axial movement of 2.64″ and 15 psig at 1231°F. PMI, x-ray and dye penetration tests were performed prior to shipment.
Single Expansion Joints > Blog Articles
These single expansion joints are 20″ in overall length and range in diameter from 3″ to 56″. They are composed of 321 stainless steel bellows, 316L flanges and angles, and include carbon steel covers. The expansion joints were designed for 194°F at 22 PSIG and were dye penetrant examined and soap and air tested prior to shipping to Peru.
U.S. Bellows custom designed 14″ dia. and 84″ dia. single expansion joints for a pipe line in an utility plant in Colorado. The bellows are 304 stainless steel and carbon steel was used for the flanges and tie rods. The assemblies were designed for a spring rate of 2,530 lb/in., 1″ axial movement at 300°F and 37 psig. The assemblies were dye penetrant examined and air tested with a delivery of 12 weeks.
U.S. Bellows designed a 102″ dia. single hinged expansion joint and duct work assembly, along with two 92″ single expansion joints for a coal gasification facility in Mississippi. Both the assembly and expansion joints were fabricated from carbon steel with 304 stainless steel bellows, and designed for 3.6° angular movement at 825°F and 3 psig. The expansion joints were dye penetrant examined, 100% x-rayed and soap and air tested prior to shipment.
A custom fabricated 31″ I.D. turbine expansion joint was designed and fabricated to be placed in service for a company in Texas. The expansion joint unit was reverse engineered, from the previous unit, with improvements to the current design. It is fabricated from 321 stainless steel with Inconel 625 bellows. The turbine expansion joint is 36″ long and is designed for 70 PSIG at 450 deg. F and axial travel of 4″. The expansion joint was 100% dye-penetrant examined and hydro-tested prior to being shipped to the customer.
U.S. Bellows designed and fabricated tied universal expansion joints and single hinged expansion joints for a power plant in Canada. All the units were fabricated from carbon steel with 316 stainless steel bellows. The universal tied joints are 102″ diameter, 225″ long and are designed for 8.2″ lateral movement. The hinged joints are 102″ diameter, 71″ long and designed for 0.76° angular rotation. Each expansion joint can withstand temperatures up to 250°F at 7.25 psig. The bellows and pipe long seams were 100% x-rayed, and all the welds were 100% dye penetrant tested. A soap and air test was performed prior to shipment.
This 48-3/4″ diameter single metallic expansion joint will be used in a heat exchanger. The bellows are 321 stainless steel and the pipe is 304 L stainless steel. This expansion joint is rated for 145 psi with 1″ compression and temperatures up to 600°F. The unit was 100% x-ray tested, hydro-tested and 100% dye penetrant tested.
The single expansion joint is simply a bellows element with end connections. Regardless of accessories, such as liners and covers, it will deflect in any direction or plane that the bellows will. It is the least expensive type, but requires that the piping be controlled as to the direction of the movements required of the unit. The expansion joint should not be expected to control the movement of the pipe. If the piping analysis shows that the expansion joint must accept axial compression, then the piping must be guided and constrained so that only that movement will occur.
This expansion joint will not resist any deflections with any force other than the resistance of the bellows, which is a function of the spring rate times the deflection amount. It is incapable of resisting the pressure thrust along its axis, which is the product of the pressure times the effective, or cross sectional, area of the bellows. Large diameter units, even with low pressures, can generate very large axial pressure thrust forces, which must be reacted by main and directional anchors. Otherwise the expansion joint will extend with disastrous results.
Projects Including Single Expansion Joints:
U.S. Bellows offers all types of metallic expansion joints. Each type has advantages and limitations that can provide flexibility, load reduction, structural integrity and reliability required in a piping system.
Metal expansion joints can withstand the design temperatures and pressures, as well as provide the capacity necessary to absorb thermal growth of the piping system. The thermal movement required can be axial, lateral or angular. In some cases, the pressure thrust of an expansion joint must be restrained by the use of tie rods, hinges or a gimbal while allowing the bellows to move through its design deflections.
Learn more about the different types of metallic expansion joints: