Question 1

What is a metal expansion bellows?

Accepted Answer

A metal expansion bellows (also called a metallic expansion joint or stainless bellows compensator) is a multi-ply stainless steel bellows that absorbs axial, lateral, angular or universal movement in high-temperature steam, hot oil, flue gas and exhaust pipework. Built to EJMA standards.

Question 2

When should I use metal expansion bellows instead of rubber?

Accepted Answer

Use a metal expansion bellows for service above ~110 °C, for steam, hot oil, high-pressure gas or where ozone / UV / chemical exposure rules out elastomers. Rubber bellows are best for lower-temperature water systems where vibration isolation matters — see our rubber vs metal guide.

Question 3

How long do stainless steel bellows last?

Accepted Answer

Manufactured to EJMA Section 4 and operated within their rated movement cycle count, a 321 or 316L stainless metal expansion bellows typically delivers 20+ years of service. Cycle count, temperature swing and corrosion environment matter more than calendar age.

Question 4

What is the difference between axial, lateral and universal expansion joints?

Accepted Answer

Axial joints absorb pipe growth along the centreline only. Lateral (tied) joints absorb perpendicular offset between two anchors. Universal joints combine two bellows on a centre spool to absorb large lateral or angular movements in long pipe runs.

Question 5

Do I need tie rods on a metal expansion bellows?

Accepted Answer

Yes whenever the pipework is not anchored either side of the joint, or where pressure thrust exceeds the bellows' self-restraint rating. Tie rods convert pressure thrust into a tensile load reacted by the rods rather than the bellows convolutions.

Metal Expansion Bellows — Stainless Steel EJMA Compensators

Popular sizes — UK stock

Sized for your system, priced per SKU

Metal Expansion Bellows DN50 (2")

Metal Expansion Bellows DN65 (2½")

Metal Expansion Bellows DN80 (3")

Metal Expansion Bellows DN100 (4")

Metal Expansion Bellows DN125 (5")

Metal Expansion Bellows DN150 (6")

Metal Expansion Bellows DN200 (8")

Metal Expansion Bellows DN250 (10")

Metal Expansion Bellows DN300 (12")

Why specify our metal expansion bellows

Metal expansion bellows specifications

Quick answers before you order

Specified by UK engineers

Plate Heat Exchanger

Low Loss Headers

Side Stream Filtration