Expansion Compensators & Housed Expansion Joints

Expansion Compensators and Housed Expansion Joints are fundamentally a bellows that is protected by and guided within a pipe housing. They are also designed to give improved stability.

While the industry offers two styles, one of which is referred to as “internally” and the other “externally pressurised”, they both serve the same function. However, we prefer the “externally pressurised” for improved bellows stability. They are furnished with a fixed ASA-150 Drilling (other drillings are available) Raised Face Carbon Steel Flange on the one end and a Floating Flange on the other (FFL). The alternates are Carbon Steel Threaded Nipples (MN), Weld or Grooved Ends (W/WGN) or Copper Female Sweat Ends (CPS) as needed. These products are typically supplied in 304 stainless steel. They are designed to achieve a 3.5 minimum safety factor for both bellows and housing.

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 1-1/2” (38mm) extension. When the rated inward motion is increased to 4” (100mm) or more, the industry name changes to “Housed Expansion Joints”, instead of “Expansion Compensator” which is the name for the products for lesser movement. 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.

• Good operating clearances to prevent binding.
• A much better looking mechanism that can be used to partially compress joints prior to installation to allow for contraction as well as expansion on installations with temperatures below ambient when in service.
• The locking device is a permanent part of the construction. They can always be tightened to hold the expansion joint in a particular position for removal while piping is serviced.
• A depth gauge on the moving end to monitor movements, make certain that joints are at the zero position before installation, or used to pre-set joints in some preferred position.
• Great attention to canister and pipe welding details.
• Internal and external clearances to prevent bellows wear because of rubbing.
• Safety factors between 3.5 and 4 compared to others at 2.25.
• Double drains on most designs, generous lifting near the centre of gravity for easier handling.
• A raised face flange and a floating flange on all flanged products for easier installation and bellows anti-torquing protection.
• Grooved fittings are bevelled as well to allow welding into pipelines as an alternate method. (Mason does not typically recommend welding.)

ECFFL – 2” (50mm) Movement Expansion Compensator with Fixed and Floating Flanges

Our Expansion Compensators for up to 2” (50mm) movement are available with carbon steel plate floating and fixed raised face flanges. The typical flange drilling is ASA-150, however alternative flange drillings are available on request. Pipe sizes from 3/4” (20mm) to 4” (100mm) are available in the product range.

ECMN – 2” (50mm) Movement Expansion Compensators with Threaded Nipples

Our Expansion Compensators for up to 2” (50mm) movement are also available with Carbon Steel threaded nipple ends. The typical flange drilling is NPT, however alternative threads are available on request. Pipe sizes from 3/4” (20mm) to 4” (100mm) are available in the product range.

HEJFFL – Housed Expansion Joint with Fixed and Floating Flanges

Our Housed Expansion Joints for inward movement of 4” (100mm) and above can be supplied with carbon steel plate floating and fixed raised face flanges. The typical flange drilling is ASA-150, however alternative flange drillings are available on request. Pipe sizes from 2” (50mm) to 14” (350mm) are available in the product range.

HEJW – Housed Expansion Joint with Weld Ends

Our Housed Expansion Joints for inward movement of 4” (100mm) an above can also be supplied with bevelled weld end one side and fixed end at the other. Pipe sizes from 2” (50mm) to 14” (350mm) are available in the product range.

Further product variants are available as stated above. If you would like to order or learn more about these products, please contact Mason UK’s friendly team of engineers.