Valve Installation Taboos And Troubleshooting （Ⅱ）

Valve Installation Taboos and Troubleshooting （Ⅱ）

Taboo 8: The pipeline is directly buried in the frozen soil and untreated loose soil. The spacing and position of the pipeline piers are improper, even in the form of dry yard bricks.

Consequences: Due to the unstable support, the pipeline was damaged during the backfilling process, resulting in rework and repair.

Measures: The pipeline shall not be buried on frozen soil and untreated loose soil. The spacing of the supporting piers shall meet the requirements of the construction specifications. The supporting pads shall be firm, especially at the interface of the pipeline, and shall not bear shearing forces. Brick piers shall be built with cement mortar to ensure integrity and firmness.

Taboo 9: The material of the expansion bolts used to fix the pipe bracket is inferior, the diameter of the expansion bolts installed is too large, or the expansion bolts are installed on brick walls or even lightweight walls.

Consequences: The pipe support is loose, the pipe is deformed, or even falls off.

Measures: Qualified products must be selected for the expansion bolts. If necessary, samples should be taken for testing and inspection. The diameter of the expansion bolts should not be greater than the outer diameter of the expansion bolts by 2 mm. The expansion bolts should be used on concrete structures.

Taboo 10: The flange and gasket of the pipeline connection are not strong enough, and the connection bolt is short or thin. Rubber pads are used for thermal pipes, asbestos pads are used for cold water pipes, and double-layer pads or bevel pads are used.

Consequences: Flange connection is not tight, even damaged, and there is leakage. The flange gasket protruding into the pipe will increase the resistance of the water flow.

Measures: Pipe flanges and gaskets must meet the design working pressure requirements of the pipeline. Flange gaskets for heating and hot water supply pipes should be rubber asbestos pads; flange gaskets for water supply and drainage pipes should be rubber pads. The gasket of the flange shall not protrude into the pipe, and its outer circle is suitable to the flange bolt hole. No bevel pad or several gaskets should be placed in the middle of the flange. The bolt diameter of the connecting flange should be less than 2mm than the flange hole diameter. The length of the bolt rod protruding nut should be 1/2 of the nut thickness.

Taboo 11: During the hydraulic pressure strength test and tightness test of the pipeline system, only the pressure value and water level changes are observed, and the leakage inspection is not enough.

Consequences: Leakage occurs after the pipeline system is in operation, affecting normal use.

Measures: When the pipeline system is tested according to the design requirements and construction specifications, in addition to recording the pressure value or water level changes within the specified time, it is especially necessary to carefully check whether there is a leakage problem.

Taboo 12: Sewage, rainwater, and condensate pipes are concealed without water-closing tests.

Consequences: It may cause water leakage and user losses.

Measures: The water shut-off test should be checked and accepted in strict accordance with the specifications. The buried sewage, rainwater, condensate pipes, etc. in underground installations, suspended ceilings, and pipe rooms should be ensured to ensure no leakage.

Taboo 13: The pipeline system is not carefully flushed before completion, and the flow rate and speed cannot meet the pipeline flushing requirements. Even the flushing is replaced by the hydraulic pressure test drain.

Consequences: The water quality does not meet the requirements for the operation of the pipeline system, which often results in the reduction or blockage of the pipeline section.

Measures: Use the maximum set juice flow in the system or the water flow speed should not be less than 3m / s for flushing. The water color and transparency of the outlet and the water color and transparency of the inlet should be visually consistent.

Taboo 14: Water pressure test under negative temperature during winter construction.

Consequences: Because the tube quickly freezes during the hydrostatic test, the tube freezes.

Measures: Try to carry out the water pressure test before winter application, and blow the water after the pressure test, especially the water in the valve must be cleared, otherwise the valve will freeze and crack. The project must be carried out under the water pressure test in winter, and the indoor positive temperature must be maintained. After the pressure test, the water must be blown off. When the water pressure test cannot be carried out, compressed air can be used for the test.