Failure

Causes

Troubleshooting

Leakage at packing

(1)The packing used beyond the time limit has aged;

(2)The force during operation is too excessive;

(3)The bolts of packing bushing are not tightened.

(1)Replace the aged and damaged packing in a prompt manner, and place it circle by circle, with the joint at an angle of 30°~45°;

(2)Operate it evenly with normal force, and do not add casing or lengthen the moment arm by other methods.

(3)Tighten the bolts for packing evenly.

Leakage at gasket

(1)The operation is not stable, causes pressure and fluctuation of temperature;

(2)The pressing force of the gasket is insufficient;

(3)The pressing force of the gasket is uneven.

(1)Make careful adjustment and operate it smoothly

(2)Make the pre-tightening force up to the requirements, and "hot tight" it after heating up.

(3)Tighten the bolts evenly and symmetrically.

Leakage of sealing face

(1)The direction of installation is not consistent with the flow direction of medium;

(2)It is not fully closed;

(3)Scale accumulates on the sealing face of the valve that has been closed for a long time;

(4)The sealing face is slightly scratched;

(5)The sealing face is severely damaged.

(1)Carry out installation inspection;

(2)Re-adjust the adjusting screws on the actuator and fully close it;

(3)Make the valve open a little, and let the high-speed water flow wash away the scale;

(4)Trim the sealing face;

(5)Replace the sealing face.

Leakage at flange joint

(1)The tightening force of bolts is uneven;

(2)The gasket is aged;

(3)The selected material of the gasket does not conform to the requirements of working conditions.

(1)Tighten the bolts evenly again;

(2)Replace the gasket;

(3)Re-choose an appropriate gasket in view of the working condition.

Leakage caused by falling off of closed parts

Improper operation causes the closing piece to be stuck too tightly or exceed the upper limit, causing the joint to break.

Perform correct operations. Do not open or close the valve with too much force or open the valve beyond the upper limit. After fully opening, the handwheel should be reversed slightly.

Inflexible operation of the stem

(1)The trapezoidal thread is unclean, and the lubrication condition is poor;

(2)Improper operation results in the deformation of the stem as well as related parts, and the damaged stem is pushed too tightly or the closing piece is stuck too tightly.

(1)Maintain the thread pair, clean, lubricate and coat it with molybdenum disulfide from time to time;

(2)Perform correct operations with appropriate force;

(3)Perform correct operations and unload it regularly, i.e., reverse the handwheel a little to prevent the top of the stem from being too tight.