Rubber expansion joint, REJ series

A rubber expansion joint is a flexible connector manufactured from natural or synthetic elastomers, technical textiles and metal reinforcements. Expansion joints relieve stresses in piping systems, caused by temperature fluctuations, mechanical vibrations and movements.

Rubber expansion joint is also called rubber tube soft joint, flexible rubber joints, rubber soft joints, flexible rubber joints, high pressure rubber joints, rubber shock absorbers, compensators, etc.

Main data of rubber expansion joint

According to the connection method, there are three kinds of flange type, fixed flange type and thread type; according to the structure, it can be divided into five types: single sphere, double sphere, different diameter body, curved sphere and wind pressure coil. The tubular rubber piece is composed of inner and outer rubber, ply and traveler, and is formed by vulcanization molding and loosening with metal flange or parallel joint. This product can reduce vibration and noise, and can compensate for thermal expansion and contraction caused by temperature changes, and is widely used in various piping systems.

Nominal diameter(DN) Length
Axial displacement(mm)
Horizontal displacement Deflexion angle
mm inch mm Extension Compression mm (a1+a2)°
32 1 1/4 95 6 9 9 15°
40 1 1/2  95 6 10 9 15°
50 2 105 7 10 10 15°
65 2 1/2 115 7 13 11 15°
80 3 135 8 15 12 15°
100 4 150 10 19 13 15°
125 5 165 12 19 13 15°
150 6 180 12 20 14 15°
200 8 210 16 25 22 15°
250 10 230 16 25 22 15°
300 12 245 16 25 22 15°
350 14 255 16 25 22 15°
400 16 255 16 25 22 15°
450 18 255 16 25 22 15°
500 20 255 16 25 22 15°
600 24 260 16 25 22 15°

Installation des compensateurs caoutchouc

Compensation of axial movement with a compensator without tie rods

Compensation of axial and lateral movement with compensators without tie rods

Compensation of lateral and axial movement with compensators without tie rods on each pipe

Compensation of a large axial movement with two hinge compensators

Compensation of movements in 2 planes with 3 angular compensators. The advantages are the absorption of large movements, weak adjustment force, weak movement resumption

Compensation of lateral and axial movement with compensators without tie rods on each pipe

Frequently Seen Signs of Flexible Rubber Expansion Joint Fatigue


Exterior surface cracking is most commonly the result of aging or elevated temperature. Because of rubber ages, it becomes hard and brittle and loses inherent flexibility and resilience. Cracking or crazing may not be serious if only the outer cover is involved and the fabric is not exposed. If necessary, repair onsite with rubber cement where cracks are minor. Carefully inspect cracks to determine if underlying fabric reinforcing plies are compromised.

Exposure of Metal Reinforcement:

If the metal reinforcement of an flexible rubber expansion joint is visible through the cover, the rubber expansion joint should be replaced ASAP.


Any inspections should verify that the installation is correct; no excessive misalignment between the flanges exists; and the installed face-to­-face dimension is correct. Check for over-elongation, over­ compression, lateral or angular misalignment. If incorrect installation has caused the expansion joint to fail, adjust the piping and order a new expansion joint to fit the existing installation.

Rubber Deterioration:

If the joint feels soft or gummy, plan to replace the flexible rubber expansion joint as soon as possible. Chemical attack is the most likely cause.


It is most important to determine where the leak originated prior to implementing any corrective action. If leakage or weeping is occurring from any surface of the expansion joint, except where flanges meet, replace the joint immediately.

Rubber expansion joints have been specified and successfully used for many years to accommodate pressure loads, relieve movement stresses, reduce noise, isolate vibration, compensate for misalignment after plants go on stream and prolong the life of pumps and other motive equipment.

Fitting specification, Standard and identification

There are different varieties of pipe fittings made of various materials and available in various shapes and sizes.


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