Metal Bellows Expansion Joints
Fully annealed stainless steel bellows expansion joints for thermal movement in piping, from vacuum to 300 psi and 200°F to 1500°F, in standard sizes from 2 inch to 144 inch with welding nipples or fixed and floating flanges.
Metal bellows expansion joints are produced from fully annealed stainless steel sheet rolled into a tube and seam welded. They are primarily used to absorb movements in piping caused by thermal changes, in service where rubber and PTFE cannot survive the temperature. Units are capable of handling vacuum to 300 psi.
Standard fittings are welding nipples and fixed and floating flanges. Standard sizes run from 2 inch to 144 inch at temperatures from 200°F to 1500°F. Send us the pipe size, media, temperature, pressure, and movement and we will size the bellows.
Stainless Steel Bellows
Why Metal Bellows
Size, Pressure, and Overall Length
Pressure rating and overall length by nominal size. Scroll the tables on smaller screens.
| Size (Inches) | Pressure (psi) | Overall Length (Inches) |
|---|---|---|
| 2in | 50 to 300 | 6 |
| 2-1/2in | 50 to 300 | 7 |
| 3in | 50 to 300 | 9 |
| 3-1/2in | 50 to 300 | 9 |
| 4in | 50 to 300 | 9 |
| 5in | 50 to 300 | 10 |
| 6in | 50 to 300 | 10 |
| 8in | 50 to 300 | 10 |
| 10in | 50 to 300 | 10 |
| 12in | 50 to 300 | 10 |
| 14in | 50 to 300 | 12 |
| 16in | 50 to 300 | 12 |
| 18in | 50 to 300 | 12 |
| 20in | 50 to 300 | 14 |
| 22in | 50 to 300 | 14 |
| 24in | 50 to 300 | 14 |
| 30in | 50 | 14 |
| Size (Inches) | Pressure (psi) | Overall Length (Inches) |
|---|---|---|
| 36in | 50 | 14 |
| 40in | 50 | 14 |
| 42in | 50 | 14 |
| 46in | 50 | 14 |
| 48in | 50 | 14 |
| 50in | 25 | 14 |
| 52in | 25 | 14 |
| 54in | 25 | 14 |
| 60in | 25 | 14 |
| 66in | 25 | 14 |
| 72in | 25 | 14 |
| 84in | 15 | 14 |
| 96in | 15 | 14 |
| 108in | 15 | 14 |
| 126in | 15 | 14 |
| 132in | 15 | 14 |
| 144in | 15 | 14 |
Ratings are maximums for each size. Confirm limits for your specific media, temperature, pressure, and movement with an Anchor Seals Inc. representative.
Frequently Asked Questions
All Expansion JointsWhen should I choose a metal bellows over a rubber or PTFE expansion joint?
Choose metal bellows when the temperature is beyond what rubber or PTFE can survive, from 200°F up to 1500°F, or when the line runs under vacuum or at pressures to 300 psi. Steam, exhaust, hot process gas, and high temperature liquid lines are typical applications.
Why does the pressure rating drop with size?
A larger bellows has more area for the internal pressure to act on, so the same wall must hold a greater total force. Standard sizes through 24 inch are rated 50 to 300 psi, 30 to 48 inch at 50 psi, 50 to 72 inch at 25 psi, and 84 to 144 inch at 15 psi. Higher pressures in large sizes can be engineered on request.
What end fittings are available?
Standard fittings are welding nipples for a welded installation and fixed or floating flanges for a bolted one. Floating flanges rotate freely on the nipple so the bolt holes can be aligned to the mating flange during installation.
What information do you need to quote a metal bellows joint?
Pipe size, media, operating and design temperature and pressure, the axial, lateral, and angular movements to be absorbed, the installed overall length, and the end fitting. A sketch or the tag from the joint being replaced is also helpful.
