14 Contraindications for Valve Installation and Their Release Measures (Part 2)

Mar. 25, 2020

TheSingle seated globe valve manufacturer will summarize some precautions when installing the valve.

Taboo 6: No holes or embedded parts are reserved in the construction of the building structure, or the size of the reserved holes is too small and the embedded parts are not marked.

Consequences: During the construction of heating and sanitary engineering, picking up the building structure, or even cutting off the reinforced steel bars, affects the safety performance of the building.

Measures: Familiarize yourself with the construction drawings of the heating and sanitary engineering. According to the needs of the installation of pipelines and hangers, take the initiative to carefully cooperate with the reserved holes and embedded parts in the construction of the building structure. Refer to the design requirements and construction specifications.

Taboo 7: When the pipe is welded, the misalignment of the pipe behind the counterpart is not on a center line, there is no gap in the counterpart, the thick-walled pipe is not shoveled, and the width and height of the weld do not meet the requirements of the construction code.

Consequence: The misalignment of the pipe is not directly on the centerline, which directly affects the welding quality and the quality of the look and feel. There is no gap at the mouth, no beveling for thick-walled pipes, and the welding can not meet the strength requirements when the width and height of the weld do not meet the requirements.

Measures: After welding the pipe counterparts, the pipes must not be staggered. A gap must be left on the centerline of the pipe. Thick-walled pipes must be shoveled. In addition, the width and height of the weld should be welded in accordance with the requirements of the code.

Taboo 8: The pipeline is directly buried in frozen soil and untreated loose soil, and the distance and location of the support pier of the pipeline are improper, even in the form of dry code bricks.

Consequence: Due to the unstable support of the pipeline, the pipeline was damaged during the compaction of the backfill soil, resulting in rework and repair.

Measures: The pipeline must not be buried in frozen soil and untreated loose soil. The distance between the pier should meet the requirements of the construction code, and the support pads should be firm, especially at the interface of the pipeline. The brick pier should be built with cement mortar to ensure completeness and firmness.

Taboo 9: The expansion bolts used to fix the pipe bracket are of poor quality. The hole diameter for installing the expansion bolts is too large or the expansion bolts are installed on brick walls or even light 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 tested and tested. The diameter of the expansion bolts should not be larger than the outer diameter of the expansion bolts by 2mm. The expansion bolts should be used on concrete structures.

Taboo 10: The flange and gasket of the pipe connection are not strong enough, the connecting bolts are short or the diameter is small. Rubber pipes are used for heating pipes, asbestos pads are used for cold water pipes, and double-layer pads or bevel pads are used. Flange gaskets protrude into the pipes.

Consequences: The flange connection is not tight, even damaged, and leakage occurs. Flange gaskets protrude into the tube and increase water resistance.

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

Globe Valve

Globe Valve

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

Consequence: Leakage occurs after the pipeline system runs, which affects 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 change within the specified time, it is particularly necessary to carefully check whether there is a leakage problem.

Taboo 12: Sewage, rainwater, and condensate pipes are concealed without a closed water test.

Consequences: May cause water leakage and user loss.

Measures: The closed-water test work shall be strictly checked and accepted in accordance with the specifications. Concealed sewage, rainwater, and condensate pipes, such as buried underground, inside the ceiling, and between the pipes, must be ensured to be leak-proof.

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

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

Measures: Wash with a large juice flow in the system or a water flow speed that should not be less than 3m / s. It shall be qualified that the color and transparency of the water at the outlet and the color and transparency of the water at the inlet are consistent with visual inspection.

Taboo 14: Hydraulic tests are performed at negative temperatures during winter construction.

Consequence: The tube freezes quickly due to the rapid freezing in the tube during the hydrostatic test.

Measures: Try to perform a hydraulic pressure test before winter application, and blow the water after the pressure test, especially the water in the valve must be cleaned, otherwise the globe valve will freeze and crack. The project must be carried out at a positive indoor temperature during the hydrostatic test in winter, and the water should be blown off after the test. When the hydraulic test cannot be performed, the test can be carried out with compressed air.