Threaded Union Type Rubber Expansion Joint
A compact moulded rubber bellows with threaded union ends — the flexible connector for small-bore threaded pipework from DN15 to DN80, fitted without flanges or welding.
Technical Data
| Product code | T281 |
|---|---|
| Body | Moulded rubber bellows, fabric reinforced |
| Rubber | EPDM / NBR / CR / NR |
| Ends | Threaded union nuts |
| Union material | Malleable iron / SS304 / SS316L |
| Size range | DN15 – DN80 |
| Working pressure | Up to 25 bar |
| Burst pressure | 3 × working pressure |
| Temperature | -20 °C to +110 °C |
| Movement | Limited axial, lateral & angular |
Movements absorbed
Axial compression
Axial extension
Lateral deflection
Angular deflectionSize & Order Codes
| DN | Length (mm) | Union material | Product code |
|---|---|---|---|
| 15 | 200 | SS304 | T281_100000000-00 |
| 15 | 200 | SS316L | T281_100000001-00 |
| 15 | 200 | Malleable iron | T281_100000002-00 |
| 20 | 200 | SS304 | T281_100000003-00 |
| 20 | 200 | SS316L | T281_100000004-00 |
| 20 | 200 | Malleable iron | T281_100000005-00 |
| 25 | 200 | SS304 | T281_100000006-00 |
| 25 | 200 | SS316L | T281_100000007-00 |
| 25 | 200 | Malleable iron | T281_100000008-00 |
| 32 | 200 | SS304 | T281_100000009-00 |
| 32 | 200 | SS316L | T281_100000010-00 |
| 32 | 200 | Malleable iron | T281_100000011-00 |
| 40 | 200 | SS304 | T281_100000012-00 |
| 40 | 200 | SS316L | T281_100000013-00 |
| 40 | 200 | Malleable iron | T281_100000014-00 |
| 50 | 200 | SS304 | T281_100000015-00 |
| 50 | 200 | SS316L | T281_100000016-00 |
| 50 | 200 | Malleable iron | T281_100000017-00 |
| 65 | 265 | SS304 | T281_100000018-00 |
| 65 | 265 | SS316L | T281_100000019-00 |
| 65 | 265 | Malleable iron | T281_100000020-00 |
| 80 | 280 | SS304 | T281_100000021-00 |
| 80 | 280 | SS316L | T281_100000022-00 |
| 80 | 280 | Malleable iron | T281_100000023-00 |
Selection Guide
Moulded bellows with galvanised malleable iron union ends. The everyday small-bore connector.
Best forHVAC · boosters · risersSS304 or SS316L unions for corrosive surroundings and hygienic plant.
Best forCorrosive / washdown areasEPDM for water and HVAC, NBR for oils and compressed-air condensate.
Best forMedia-matched serviceDatasheet & Drawings
Threaded union joint specifications and order codes on one page, plus the technical drawing. A certified approval drawing follows with your quotation.
EN 10204 3.1 material certificates are supplied with your shipment.
Also in This Range
Frequently Asked Questions
Where are threaded union rubber joints used?
On small-bore threaded pipework — booster sets, circulators, small pumps and HVAC branches — where a flanged joint would be too big and a quick screw-in connection is preferred.
What thread types are available?
Female union nuts in BSP (parallel or tapered) or NPT, chosen to match your pipe and fitting threads.
What sizes does it cover?
Typically DN15 to DN50 (½" to 2"), at PN10 or PN16.
Do the union nuts turn freely?
Yes. Each nut swivels on the joint, so you can tighten the connection without twisting or damaging the rubber body.
Which elastomer should I choose?
EPDM for water, chilled water and HVAC; NBR for oil or fuel; CR or chlorobutyl for chemical duty — selected from the medium and temperature.
How is it removed for maintenance?
Simply unscrew both union nuts and lift the joint out; there is no need to cut the pipe or disturb the surrounding fittings.
Engineered to order. Delivered worldwide.
Send your duty conditions — size, pressure, temperature, medium and connections — and our engineers return a drawing, material selection and lead time.
Request a quote