Control valve leakage protection Part 1- for Plug valve and Ball valve


#1

Good care must be given to control valve to reduce the problems that may be possible repairs and leakage without shutting down the system when not harmful. If in a dangerous position then the repair of the valve must be done in the shop or the system is turned off.

Here we have leakage check for plug valve and ball valves.

Leakage protection for Plug valve:

  • Periodic observations need to be made to ensure that the Plug valve works normally and does not leak.

  • Check for leaks that occur between the bonnet cap and the body. If this happens, the cause may be fluctuations in heat and pressure loads. Depressurize the fluid trapped in the area, then tighten the bonnet cap bolt according to the specified torque. If it still leaks, the valve needs to be repaired at the shop.

  • If a leak occurs on the shaft and bonnet cap, the main cause is a bad sealing system between the valve and the seat.

  • Check the possibility of wear damage to the inner diameter or consolidation of packing or diaphragm. If using an O-ring gasket, it is possible that the O-ring has been damaged and needs to be replaced with a new one, to improve the sealing capability of the sleeve, tighten the top so that the cone valve is more in sleeve. This will increase the sealing capability between the body-sleeve and plug. Also tighten the gland flange to increase the sealing between the valve shaft and the diaphragm and packing.

  • If it’s still leaking, replace the soft component (gasket, etc.) with a new one. Bolt tightening can improve sealing valve capability. But this will cause an increase in torque to operate the valve and speed up the damage process to the valve components due to wearing, especially on the sleeve. If the bolt tightening does not stop the leak, the sleeve may be damaged and needs to be replaced.

  • If a leak occurs at the flange, tighten the bolt in a criss-cross manner. If it is still leaking, chances are the flange gasket surface is damaged or the gasket needs to be replaced.

Leakage protection for Ball Valve:

For ball valve, leaks can occur on the end connection (flange connection), split body connection and between the bonnet stamp with the body.

  • If a leak occurs at the flange connection, tighten the bolt in a cross-sectional manner, if it is still leaking, the flange gasket may be damaged or the gasket needs to be replaced.

  • If a leak occurs in a split-body connection, it is generally caused by an unbalanced compression force on the piping. Check whether piping support has guaranteed the location of the pipe in a straight position. Then tighten the bolt to the split-body. If there is still a leak, the gasket or the surface has been damaged and needs to be replaced.

  • Check for leaks that occur between the bonnet cap and the body. If this happens, the cause may be fluctuations in heat and pressure loads. Depressurize the fluid trapped in the area, then tighten the bonnet cap bolt according to the specified torque. If it’s still leaking, dismantle the valve and check the surface.

  • If a leak occurs on the shaft and bonnet cap, the main cause is a bad sealing system between the valve and valve. Check the possibility of wear damage to the inner diameter or consolidation on packing.

  • If a leak occurs on the ball, the possible cause is: the seat is damaged, there is an object stuck between the seat and the valve (ball) inadequate compression force on the ball-seat assembly. The ball is damaged by compression.