U.S. Bellows, Inc. fabricated this 30″ spent standpipe catalyst metallic expansion joint for a refinery in Montana. The overall installed length of the expansion joint is 89″. The design pressure was 19 PSIG and the design temperature was 1050°F. The expansion joint is fabricated entirely from 321 stainless steel, except for the carbon steel flanges to match the existing nozzle material and drilling. The assembly is lined with abrasion-resistant refractory which prevents erosion of the 321 stainless steel piping. The pantographic linkage, shown in the photo, is designed to distribute the axial compression between the two bellows and support the weight of the center pipe between the bellows.
This expansion joint was pneumatically tested to 55 PSIG. Positive Material Identification was performed on all alloy materials. All of the longitudinal welds were 100% x-ray tested