Expansion Compensators and Housed Expansion Joints are basically a bellows that is protected by and guided within a pipe housing. While the industry offers two styles, one of which is referred to as “internally” and the other “externally pressurized”, they both serve the same function but we prefer the “externally pressurized” for improved bellows stability. They are furnished with a Fixed ASA150 Drilling Raised Face Carbon Steel Flange on the one end and a Floating Flange on the other. The alternates are Carbon Steel Threaded Nipples, Weld or Grooved Ends or Copper Female Sweat Ends as needed.
There are three movement choices: 2” (50mm) compression and 1/2” (13mm) extension, 4” (100mm) compression and 3/4” (19mm) extension or 8” (200mm) compression and 11/2” (38mm) extension. They are all designed for systems that will run hot and the slight extension is only there for those occasions when ambient temperatures are fairly high during installation, and the installation drops to some very low temperatures before they are put into hot water or steam service.