Installation requirements for corrugated expansion joints

Installation requirements

1. Before installation, the expansion joint should check its model, specification and pipeline configuration, and must meet the design requirements, including product appearance inspection, especially whether the surface of the bellows has mechanical damage caused by transportation and hoisting.

2. When the design does not require pre-displacement installation, do not loosen the positioning nut or remove the transport rod or "bridge" during the entire installation period. After the expansion joints and various pipe supports are installed and passed the inspection, the pressure test The inner positioning nut on the large tie rod must be screwed to the root of the thread immediately, and the special transport screw or "bridge" must be removed immediately. Be careful not to loosen the outer nut of the large tie rod.

3. Installation direction: There is a medium flow direction sign attached to the expansion joint equipped with the guide tube, which is consistent with the medium flow direction to prevent the reverse slope direction, erosion and corrosion of the bellows, and affect the medium flow rate.

4. Installation error: The dimensional deviation and position deviation of the end face or flange end face of the pipeline connecting both ends of the expansion joint are as follows:

(1) Length deviation between surfaces: ≤±3mm

(2) Coaxiality deviation between surfaces: ≤1%DN and ≤Φ5mm (DN pipe nominal diameter)

(3) The perpendicularity deviation of the pipeline axis of each face is ≤1% and ≤3mm

At the same time, do not allow the expansion joint to bear torque during installation, and it is strictly forbidden to use the deformation method of the compensator to adjust the installation error of the pipeline.

5. The auxiliary components used for protection and pre-denaturation should be removed after the pipeline is installed and pressure tested. The general expansion joint screw the nut of the transport rod to the root of the thread or remove it; the expansion joint of the large rod screw the inner nut of the large rod to the root of the thread, and the handling method of the transport rod nut is the same as that of the general expansion joint; If the component is stuck or restricts its range of movement, the normal operation of the moving parts should be guaranteed.

6. System pressure test

The test pressure shall not exceed the specified value (the normal temperature water pressure test shall not exceed 1.5 times the design pressure, and the air pressure test shall not exceed 1.1 times the design pressure). For stainless steel bellows, the water used for the hydrostatic test shall be free of chloride ions. The system pressure test must be carried out after all pipe supports and expansion joints are installed.

7. Expansion joint and pipe assembly

Pre-positioned expansion joints are assembled with pipes after pre-positioning, and special transport nuts or "bridges" are removed before pre-positioning. Pre-displacement installation is not required. Recommended use:

(1) reserved spacing assembly method; (2) sequential assembly method.