The video shows an expansion joint bellows being cycle tested through a specified design movement of 1-1/4″ to verify the calculated life span of 30,000 cycles. The number of completed cycles is recorded throughout the duration of the test. U.S. Bellows routinely performs this test to confirm designs and ensure a high quality product. We do extensive expansion joint product testing such as x-ray, burst, hydrostatic, ultrasonic, radiography, fatigue, PMI, pneumatic, magnet particle and helium leak testing depending on customer specifications. Each bellows and expansion joint unit goes through in-process quality control using a system of travelers, and a final in-house dimensional inspection is performed prior to shipping.
Trying to decide which type of fabric expansion joint to use in your application? Our new comparison chart lists the materials, temperature ranges, advantages, pressure, chemical resistance and applications.
The following are examples of expansion joints fabricated from a variety of materials.
Expansion Joints Fabricated with Neoprene Material:
Expansion Joints Fabricated with Reinforced Silicone Material:
Expansion Joints Fabricated with PTFE Impregnated Fiberglass Material:
Expansion Joints Fabricated with Silica Fabric Cloth Material:
Hinged Universal Expansion Joint and Duct Work Assembly Custom Designed for an Exhaust Duct Application
This week’s featured product is on a hinged universal expansion joint and duct work assembly custom designed for an exhaust duct application in a power plant in Kenya. The hinge hardware was fabricated from carbon steel, while the rest of the unit was fabricated from 316 stainless steel with Inconel 625 bellows. An F-type variable spring was also provided for this project and will be used to support the center spool between the two elbows. The duct work with expansion joint is 36″ in diameter and the distance between the centerline of the two 90 degree elbows is 240″. It is designed for 20 psig at 115°F and 1/2 degree of angular movement. The entire assembly was 100% dye penetrant tested and a soap and air test was performed prior to shipment.
The existing pressure balanced elbow expansion joint with liners was re-designed with turning vanes to eliminate the vibration impact on the bellows. U.S. Bellows performed a computational fluid dynamics (CFD) analysis to determine the design of the turning vanes.
The turning vanes redirect the flow stream, which creates a smoother flow, thus eliminating the flow induced vibration. The bellows and liner were fabricated from 321 stainless steel and the rest is fabricated from carbon steel. An air and soap test was performed prior to shipping it to a power plant in Washington.
26" Diameter Pressure Balanced Elbow Expansion Joint Refurbished for an Effluent Header at Cedar Bayou Plant
U.S. Bellows, Inc. received this 26″ diameter pressure balanced elbow expansion joint for a complete refurbishment. New SA-240 type 321 stainless steel bellows were used to replace the original bellows, and the tie rods and flow liners were also replaced. All carbon steel parts were painted with a universal primer. This expansion joint measures over 17 feet long center to center of elbows, and is currently being used in an effluent header at Cedar Bayou plant.
The universal pressure balanced elbow expansion joints were fabricated with 304 stainless steel bellows and carbon steel reinforcing root rings. The expansion joints were designed for an axial compression of .25″, extension of .75″, and lateral of 1″. They have an overall length of 237″ from center line or elbow to face of the weld end. All expansion joints were designed for 100 PSIG and hydro-tested at 150 PSIG.
U.S. Bellows, Inc. designed and fabricated 36″ pressure balanced elbow expansion joints that weigh approximately 4,300 lbs each. The pressure balanced design does not exert pressure thrust on the equipment in the piping system.
The expansion joints are designed with Inconel® 625 grade LCF bellows and include a liner provided with drain holes to prevent accumulation of corrosive condensation. The design movements are 1/2″ axial compression and 3/4″ lateral movement. The bellows were 100% x-rayed before forming and dye-penetrant examined after forming.
U.S. Bellows, Inc. designed and fabricated two 44″ hinged expansion joints with 5″ thick refractory lining. These expansion joints are part of FCC stand-pipes in a synfuels plant. Each expansion joint is fabricated of two-ply Inconel® bellows and 3/4″ wall pipe. The joints consist of 2″ thick attachment rings. After fabrication, the expansion joints were pneumatically tested and inter-plies tested. The bellows and pipes were 100% x-rayed and PMI tested.
Thermal and structural Finite Element Analysis (FEA) was performed on the expansion joints to ensure the product is structurally sound and determining the thermal profile helps to prevent polythionic corrosion on the bellows. Design calculations were performed for all hardware including lug rings, gussets, hinge plates, pins, etc.
U.S. Bellows, Inc. designed and fabricated refractory lined single-hinged and universal expansion joints for a design pressure of 75.4 PSIG and 1400°F temperature. Each expansion joint was 100% x-ray tested along the weld seams and pneumatically tested to 83 PSIG.
Refurbishment of the Second of Two 54" Pressure Balanced Elbow Turbine Crossover Expansion Joints for a Power Generation Plant
The first 54″ outside diameter expansion joint leaked from a crack in the bellows causing an unscheduled power plant outage. This particular expansion joint was fabricated for a high pressure turbine crossover piping for steam service of 97 PSIG at 634°F. The 27′ long, 27,000 lb. expansion joint was refurbished in less than 4 weeks. This was made possible by utilizing dedicated employees working overtime 6 days a week. The 321 stainless steel bellows and carbon steel root rings were replaced. The outside cover bolts were removed and new bolts were installed.
The second expansion joint was also for a high pressure turbine that was replaced during a planned outage. This expansion joint came in on October 30, 2006 and was ready to ship November 20, 2006. Overall length and center line to center line length were maintained to ensure easy installation. Both expansion joints were dye-penetrant tested and hydro-tested at 146 PSIG.