In most of the direct buried pipelines in China, after the installation of the direct buried pipeline, the shell of the tetrafluoro compensator and the corrugated layer form an integral whole. Under the working condition, the insulation layer and the insulation layer can not be expanded. Therefore, the groundwater can directly contact the working pipe and the outer cavity of the compensator, even if some compensators are considered on the movable end shell. Waterproof sealing rings were used, but all of them were useless. After some engineering accidents, 100% of the water inflow was found through disintegration observation. The fine sediment of compensator without waterproof sealing measures could enter directly.

The following problems exist in the practical application of tetrafluoro compensator

1. Quality problems of tetrafluoro compensator.

In order to reduce costs, individual production enterprises should change the design material to reduce the number of layers, thickness and illegal operation of sheet metal.

2. Selection of tetrafluoro compensator.

Purchase is not carried out according to the type and parameters determined in the engineering design drawings.

Purchasing without engineering design.

(3) Error in design and selection.

3. The working environment of tetrafluoro compensator.

(1) Tetrafluoride compensator works in liquid with corrosive medium in whole or part for a long time or a short time.

(2) The working environment of tetrafluoro compensator C1 - and other corrosive media exceed the standard.

4. Material problems of tetrafluoro compensator.

Before the selection of tetrafluoro compensator, the content of C1 - and other corrosive media should not be tested in the water or soil of the place where the underground pipeline is laid, or the water quality of the area with high groundwater level should be checked only, and the material should be selected at will without paying attention to whether the groundwater contains excessive corrosive media.

5. Design fatigue life.

In some projects, the design of fatigue life or the determination of low service fatigue life are not considered in the selection of Teflon compensator in the light of external working environment.

6. Installation of Teflon Compensator.

The installation position of tetrafluoro compensator is unreasonable.

(2) Not in accordance with the requirements of the product specifications of the tetrafluoro compensator.

(3) Operations are not carried out according to design requirements and construction specifications.

7. Problems in customary practices.