January 20, 2026
U.S. Bellows custom designed these hinged expansion joints for a Polyolefin process which produces High-Density Polyethylene (HDPE) resin at a chemical plant. Polyolefins are a family of polyethylene and polypropylene thermoplastics. The job included expansion joints ranging from 12″ to 32″ NPS. The units pictured above have a nominal pipe size of 16″. The bellows and liner were fabricated from 304 stainless steel and the flanges, cover, and hardware from carbon steel. They are designed for an operating temperature of 176°F at 145 psig and 1° of angular movement. The expansion joints were 100% dye penetrant tested, the bellows longitudinal seam welds were 100% X-rayed, PMI examined, and hydro-tested prior to shipment.
