Rubber expansion joint are used to connect pipeline equipment, which can reduce vibration and noise and compensate displacement. It can reduce the vibration and noise generated when the pipeline is running, and it can absorb the size change of the pipeline due to thermal expansion and contraction within the permitted range. It cannot bear the internal pressure thrust of the pipeline, blind force, therefore, there should be fixed brackets at both ends of the rubber joint, or use rubber expansion joint with limit rods.

 Please note the following issues when installing and using rubber expansion joint.

1,Rubber expansion joints are strictly prohibited to be installed beyond the displacement limit. 

2,When installing rubber expansion joint on flat ground, overhanging or vertically, the actual working axial displacement pressure  of rubber joints is less than the support force of the pipeline, otherwise anti-pull-off devices should be installed to prevent pulling off under pressure when working.

3,The pipeline must have a fixed support or fixed bracket, and the force of the fixed bracket must be greater than the axial force.For vertical and overhead installation, corresponding fixed brackets and force brackets should be installed at both ends of the product to prevent pulling off under pressure at work.

4,The installation bolts should be tightened symmetrically and gradually to prevent local leakage.

5,The installation should be far away from the heat source, and the use of media that do not meet the requirements of this product is strictly prohibited.

Connection Mode

Generally there are thread connection, flange connection, clamp connection etc, Execution Standard：HCRJ 070-1999

Caution

1,When installing the bendable rubber joint in the pipeline, it must be in its natural state, do not artificially deform the product. When the pipeline medium is acid and alkali resistant, oil, high temperature and other special materials a joint higher than the working pressure of the pipeline should be used.

2,The flange of the rubber joint should conform to the flange standards required by the customer, such as EN1092-1,BS4504,ANSI B16.1,ANSIB16.5,AS4087 etc

3,Rubber expansion joint normal applicable medium is the temperature 0-60℃ Ordinary Water, Special Media Such As Oil, Acid And Alkali, High Temperature And Other Corrosive And Hard Texture Of The Case, Should Be Selected Corresponding To The Special Resistant Material Rubber Joints, Not Blindly String With Or General.

4, When rubber expansion joints are used in the import and export of water pumps, they should be located on the side of the water spring, and metal reducer joints should be installed between the water spring and the rubber expansion joint, and installed at the large diameter of the reducer.

5,When the displacement of the pipeline is greater than or equal to the maximum compensation of the joint, the number of joints should be increased to parallel the displacement, and it is strictly forbidden to make the joint in the limit of flexural displacement and deviation in order to adjust the pipeline’s super-difference ,and not to exceed the limit(expansion ,displacement, deflection etc)

6, For high-rise water supply or overhanging water supply, the pipe should be fixed on a hanger, bracket or anchor frame, and the joint should not be allowed to bear the pipe’s own weight and axial force, otherwise the joint should be equipped with an anti-pull- off device(it bearing force must be greater than the pipe axial force).

7,When installing the rubber expansion joint, the screw of the bolt should be extended to the outside of the joint, and the bolt of each flange end face should be tightened repeatly and evenly according to the method of diagonal pressurization to prevent pressure deviation.The threaded joint should be tightened evenly with standard spanners, do not use force to make the live joint slip silk, slip prongs and fracture, and  should be checked regularly to avoid loosening resulting in dislodgement or water speepage.

8,After the first time the rubber joint is under pressure(e.g. installation test pressure etc) or before starting again after a long period of disuse, the bolt should be re-pressurized and tightened before putting it into operation.

9,Avoid high temperature, ozone oil, acid and alkaline environment when using or storing rubber expansion joints.For pipes used outdoors or facing the sun and wind , a shade frame should be set up and sun screen, rain and wind are strictly prohibited, painting and winding of insulation materials are strictly prohibited on the surface of the joint.Due to the aging problem of rubber products, they should be checked and replaced in time.

10,When installing rubber joint on flat ground, overhead or vertically, the actual working axial displacement pressure of rubber joints should be less than the supporting force of the pipeline, otherwise anti-pull off devices should be installed to prevent the work from being pulled off under pressure.

11,Rubber Joints should be kept away from heat sources and ozone areas, and strong radiation is strictly prohibited.Exposure to sunlight and the use of media that do not meet the requirements of this product are strictly prohibited.

12,Rubber expansion joints should be transported, handled and installed in such a way that sharp instruments are not allowed to scratch the sealing surface.

13,Rubber joints should have fixed brackets at both ends, otherwise, restrictive rubber joints should be used.

The main body of a rubber joint is a rubber hose, which does not reach the same hardness and strength as a metal pipe fitting, when the pipeline is running, the fluid flows out through the pump pressure and meets the elbow or blind plate, generating internal pressure thrust, which will displace the pipeline. To solve this problem, rubber joints should be set up with fixed brackets at both ends to offset the internal pressure of the pipe and prevent the joint from elongation.It is important to know that although rubber joints have elongation characteristics, they are only used to compensate for changes in the size of the pipeline due to thermal expansion and contraction, and  can’t withstand the elongation of the pipeline.

1. Example of rubber joint installation with fixed bracket.