What are the precautions for installation and pressure test of tetrafluoro corrugated expansion joints?

First, before installation, the type and specification of corrugated Teflon expansion joint and the support configuration of pipeline should be checked first, and the composite design requirements must be met.

Secondly, for corrugated expansion joints with inner lining barrel, attention should be paid to making the direction of inner lining barrel consistent with the direction of medium flow (installation according to the direction sign of expansion joint). The hinge rotation screen of the plane angular corrugated expansion joint should be consistent with the displacement plane.

Third, the corrugated expansion joints need to be "cold-tightened". The auxiliary components used in the pre-deformation of the corrugated expansion joints should be removed after the pre-deformation of the corrugated expansion joints.

Fourthly, the auxiliary positioning mechanism and fasteners used for installation and transportation protection on corrugated expansion joints should be removed immediately after the installation of pipelines, and the limit device should be adjusted to the prescribed position according to the design requirements, so that the pipelines can be fully compensated in environmental conditions.

Fifthly, except the pre-deformation of pre-tension and compression or "cold-tightening" required by the design, it is strictly forbidden to use the method of bellows deformation to adjust the installation deviation of pipelines, so as to avoid affecting the normal function of bellows expansion joints, otherwise it will reduce their service life and increase the load of pipelines, equipment and supporting components.

Sixthly, all the movable components of the bellows expansion joint shall not be stuck by the external components or restrict the normal movement of the movable parts of the bellows expansion joint.

Seventh, during installation, no welding slag is allowed to splash on the surface of the group bellows and other mechanical damage to the bellows is allowed.

Eighth, when conducting hydraulic tests on expansion joints and connecting pipes used in gas media, it is necessary to consider whether temporary brackets are needed to support the nozzles of bellows expansion joints when filling water.

9. Water for hydraulic test must be pure and non-corrosive, and the content of chloride ion in water should not exceed 25 ppm. After the hydraulic test, the accumulated water in the bellows should be drained out as soon as possible and the inner surface of the bellows should be dried quickly.

Tenth, the neutrality of the pipeline is good. When there is no other way to guarantee it, the method of cutting the equal length pipeline after laying the straight pipe and installing expansion joint can be used to ensure it.

11. It should be noted that expansion joints do not absorb torque, so when installing expansion joints, they are not allowed to be twisted.

12. All movable components of bellows expansion joints shall not be stuck by external components or restrict the normal operation of their movable parts.

Thirteen, the insulation layer should be made on the protective cover of the expansion joint, not directly on the bellows. Thermal insulation materials containing chlorine shall not be used.

14. During installation, no welding slag is allowed to splash on the surface of bellows and other mechanical damage to bellows is allowed.

Fifteenth, the bracket must meet the design requirements. It is strictly prohibited to test the pressure in the pipeline before the bracket is installed, so as not to pull the expansion joint out.

Sixteen, bellows expansion joint allowed no more than 1.5 times nominal system pressure test.

Seventeen. In the operation of pipelines with corrugated expansion joints, the opening and closing of valves should be carried out gradually, so as to avoid drastic changes in temperature and pressure in the pipeline, causing damage to brackets or expansion joints.