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How to avoid valve failure ?

Jul 29, 2019

How to avoid valve failure ?


Prevent valve leakage. All valves must be tested for different levels of water pressure after entering the plant.

  Valves that need to be disassembled and repaired must be ground. In the process of repair

it is necessary to carefully check whether the disk root is added and whether the disc root pressure cover is tightened.

    

   The valve must be checked for dust, sand, iron oxide and other sundries inside the valve before installation.

   If there is any of the above sundries must be cleaned before installation. All valves must be fitted with gaskets of the corresponding grade before installation

       The fastening parts must be tightened when the flange door is installed, and the fastening parts must be tightened in symmetrical direction when tightening the flange bolt.

    In the valve installation process, all valves must be installed according to the system, pressure correctly, strictly prohibit random loading, mixed loading. For this purpose, all valves must be numbered according to the system and recorded before installation.

 

The cause of the leak :


The casting quality of iron castings is not high, there are sand eyes, loose structure, slag clamping and other defects on the valve body and valve cover body.

Poor welding, there are slag, unwelded, stress crack and other defects; cast iron valve damaged by heavy object impact.

 


preventive measure


 Improve the casting quality and carry out the strength test in strict accordance with the regulations before installation;

For valves with temperature below 0℃ and below 0℃, heat preservation or mixing shall be carried out, and the accumulated water shall be drained for the valves stopped;Welds of valve body and bonnet composed of welding shall be carried out according to relevant welding operation regulations, and flaw detection and strength test shall be carried out after welding;It is forbidden to push the heavy objects on the valve, and it is not allowed to impact the cast iron and non-metal valves by hand hammer. The installation of large diameter valves shall be supported.