How To Protect The Pump Valve

Jun 03, 2025

1, Disclosure of valve body and valve cover:
Cause:
1. The quality of cast iron casting is not high, and there are defects such as sand holes, rigorous structure, and slag inclusion on the valve body and valve cover
2. Cold weather and freezing cracks;
3. Poor riveting, with defects such as slag inclusion, lack of riveting, and stress cracks;
4. Cast iron valves are damaged after being hit by heavy objects.
Protection steps:
1. Popularize the quality of melting and casting, and continue to test the strength of the large area in front of the device according to the regulations;
2. Valves with temperatures below 0 ° C should be kept fresh or heated, and valves that remain in use should be drained of water
3. The weld seam of the valve body and valve cover composed of riveting should continue according to the unrelated riveting operation procedures, and after welding, further testing and strength testing should be carried out;
4. It is prohibited to push or place heavy objects on valves, and it is not allowed to strike cast iron and non-metallic valves with hammers. The device for large-diameter valves should have brackets.
2, Leakage at the packing point (the external leakage of the valve, with the packing point accounting for the largest proportion)
Cause:
1. The selection of packing is incorrect, it is not resistant to the erosion of the medium, and it is not resistant to the use of low pressure or vacuum, low temperature or high temperature in valves;
2. The filling device is incorrect, with drawbacks such as replacing large with small, poor drilling around joints, and loose tightening and loosening;
3. Fillers are better than their service life, as they have aged and lost their elasticity
4. The accuracy of the valve stem is not high, and it has disadvantages such as winding, erosion, and wear
5. There are too many packing rings, but the pressure cap is not tightly pressed;
6. The cover, bolts, and other components are damaged, causing the cover to be forced to tighten;
7. Improper operation, excessive force, etc;
8. The pressure cap is skewed, and the gap between the pressure cap and the valve stem is too small or too large, resulting in wear of the valve stem and damage to the packing.
Protection steps:
1. The information and type of filling material should be selected according to the working conditions;
2. If the device filling is incorrect according to unrelated regulations, the packing should be placed and compressed one by one, and the joint should be at 30 ℃ or 45 ℃;
3. Fillers with long service life, aging, and deterioration should be replaced in a timely manner;
4. The valve stem should be straightened and repaired after winding and wear, and those with significant damage should be replaced in a timely manner;
5. The packing should be installed according to the prescribed number of turns, and the pressure cover should be tightened evenly. The compression sleeve should have a pre tightening gap of over 5mm;
6. Damaged covers, bolts, and other components should be repaired or replaced in a timely manner;
7. Violation of operating procedures, except for impact handwheels, operate with uniform abnormal force;
8. The gland bolts should be tightened symmetrically and evenly. If the gap between the gland and the valve stem is too small, the gap should be appropriately increased;
The gap between the gland and the valve stem is too large and should be replaced.
3, Disclosure of Confidential Book Cover
Cause:
1. Grinding the sealing cover with compressed air to prevent the formation of a sealing line;
2. The top center of the connection between the valve stem and the open part is suspended, misaligned, or worn;
3. The valve stem winds or is disassembled improperly, causing the open part to tilt or not meet the center;
4. Improper selection of sealing material quality or failure to select valves according to working conditions
Protection steps:
1. Incorrect selection of data and type of shims based on operating conditions;
2. Careful adjustment and bumpy operation;
3. The bolts should be tightened symmetrically and evenly, and if there is excess, a torque wrench should be used. The pre tightening force should be consistent and not too large or too small. There should be a predetermined pre tightening gap at the connection between the flange and the screw buckle;
4. The disassembly of gaskets should be aligned with the center, with even force distribution. Gaskets are not allowed to overlap or use double gaskets;
5. The erosion, deterioration, and low processing quality of the static seal book cover should continue to be repaired and ground, and color review should be continued to ensure that the static seal book cover matches the original design;
6. Be careful of dirtiness when installing gaskets, use kerosene to clean the sealing cover, and the gasket should not fall to the ground.
4, Disclosure of gasket connection
Cause:
1. The gasket is not tightly rolled
2. The gasket is riveted to the body, and the welding quality is poor;
3. Loose fasteners, screws, and pressure rings for gasket connections;
5. The gasket connection is corroded.
Protection steps:
1. The sealed rolling area reveals that adhesive should be injected and then rolled vividly;
2. The gasket should be re welded according to the welding standards. When repairing welding at the welding site, the original welding and processing should be removed;
3. Remove the screws, clean the pressure ring, replace the damaged components, grind the sealing and connecting seat sealing surfaces, and disassemble them again. For components with significant erosion and damage, steps such as riveting and bonding can be used for repair;
4. The joint surface of the gasket is corroded, and can be repaired by grinding, bonding, and other steps. If necessary, the gasket should be replaced when repairing.
5, Leakage caused by detachment of open parts:
Cause:
1. Poor operation causes the open parts to get stuck or exceed the top dead center, and the connection is damaged or broken;
2. The connection of the open parts is not firm, and they loosen and fall off;
3. Choosing the wrong material for the connecting components cannot withstand the erosion of the medium and mechanical wear.
Protection steps:
1. Incorrect operation: Do not apply too much force when opening the valve. Do not exceed the top dead center when opening the valve. After fully opening the valve, the handwheel should be reversed slightly;
2. The connection between the open part and the valve stem should be firm, and there should be a stopper at the screw buckle connection;
3. The fasteners used to connect the open parts to the valve stem should be resistant to the erosion of the medium and have a certain mechanical strength and wear resistance.