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1. Causes and repair methods of stuffing box leakage Causes of failure Repair methods Incorrect filling method (such as placing the whole piece in a circle) Correct filling The valve stem is deformed or corroded or rusted Repair or replace the packing Aged replacement Use improper force or excessive force Slow open and slow close , Smooth operation 2. Causes and repair methods of valve stem failure Causes and repair methods Valve stem damage, corrosion and tripping Replace valve parts When the valve stem is bent and twisted, the valve is not easy to open. Do not use long tools to pry off the handwheel. The bent valve stem needs to be replaced with the stem nut. Replace the valve parts or valve at an angle. The open-air valve is rusty. The open-air valve should be maintained and maintained regularly. Turn the handwheel regularly. 3. Causes of sealing surface leakage and repair methods. Failure causes and repair methods. Sealing surface wear and mild corrosion. Periodic grinding. Improper closing. Poor sealing surface contact. Slow opening and closing. Repeated opening and closing several times. The valve stem is bent. The upper and lower sealing surfaces are not aligned with the center line. Repair or replace. Maintenance method and repair method Failure and cause of failure Repair method Gasket leakage The gasket material is not suitable or is affected by the medium in daily use and fails. Use a gasket that is suitable for the working conditions or replace the gasket. The valve is cracked and frozen or the threaded valve is installed with excessive force. Insulation and anti-freeze, install When installing, force evenly and appropriately. The handwheel may be damaged by the impact of heavy objects. Do not pry it open with a long rod. The inner square hole is chamfered to avoid impact. Use even force when opening and in the correct direction. File the square hole or replace the handwheel gland when the gland is broken. Tighten the nut unevenly and tighten the nut symmetrically. The gate plate fails and the wedge gate plate fails. Loose closing due to corrosion. The top wedge of the double gate plate is damaged. Periodically grind it and replace it with a top wedge made of carbon steel. Common faults and causes of automatic valves 1. Common faults, causes, prevention and repair of check valves. Causes of faults and repair methods. Backflow of medium 1. Between the valve core and the valve seat. Damage to the sealing surface 2. There is dirt between the valve core and the valve seat 1. Grind the sealing surface 2. Remove the dirt The valve core does not open 1. The sealing surface is stuck with scale 2. The rotating shaft is rusted 1. Remove the scale 2. Polish the rust to make it flexible The valve disc is broken and the medium pressure in front of and behind the valve is in contact.* * The "see-saw" state of balance causes valve discs made of brittle materials to flap frequently. Use tough material valve discs. 2. Common faults, causes, prevention and repair of traps. Failure causes and repair methods. No drainage. 1. The steam pressure is too low. 2. Steam and condensate do not enter the trap. 3. The pontoon-type pontoon is too light. 4. The pontoon-type valve stem and casing are stuck. 5. The valve hole or channel is blocked. 6. Constant The warm valve core is broken and the valve hole is blocked. 1. Adjust the steam pressure. 2. Check whether the steam pipeline valve is closed and blocked. 3. Add appropriate amount or replace the float. 4. Repair or replace it to make it flexible. 1. Grind the sealing surface 2. Check whether there is dirt blockage 3. Increase the volume of the float appropriately Continuous operating temperature drops 1. The displacement is lower than the amount of condensation water 2. The amount of condensation water in the pipeline increases 1. Replace a suitable trap 2. Install a trap 3. Common faults of pressure reducing valves, causes, prevention and maintenance Failure causes Maintenance methods The pressure behind the valve is unstable 1. Pulse type valve Improper diameter selection, large pressure difference between the media at both ends 2. Improper selection of spring-type regulating spring 1. Replace the appropriate pressure reducing valve 2. Replace the appropriate regulating spring The valve is blocked 1. The control channel is blocked by debris 2. The piston is stuck with rust and cannot move down at the highest position 1. Clear the debris and install a filter in front of the valve 2. Inspect the piston to make it flexible. The valve is straight through 1. The piston is stuck in a certain position Set 2. The spring at the lower part of the main valve disc is broken 3. The pulse valve handle is stuck in the close position 4. There is dirt stuck or severely corroded between the main valve disc and the valve seat sealing surface 5. The diaphragm fails 1. Repair the piston to make it flexible 2. Replace the spring 3. Overhaul to make it flexible 4. Remove the dirt and grind the sealing surface regularly 5. The pressure cannot be adjusted after replacing the diaphragm valve 1. Adjust the spring Failure 2. The cap is leaking and cannot maintain pressure 3. The piston and cylinder are worn or corroded 4. The valve body is filled with condensate 1. Replace the adjusting spring 2. Inspect and repair in time and replace the gasket 3. Inspect the cylinder and replace the piston ring 4. Loosen the plug and drain the condensate 4. Common faults, causes, prevention and repair of safety valves Failure causes Repair methods Sealing surface leakage 1. Valve core and There is dirt or wear on the sealing surface of the valve seat. 2. The centerline of the valve stem is incorrect. 1. Remove the dirt or grind the seal. 2. Correct and straighten the centerline of the valve stem. The valve stem does not open when the centerline exceeds the working pressure. 1. The lever is stuck or the pin is rusted. Replace the spring 4. Do regular exhaust tests and open when the working pressure is lower. 1. The weight of the lever moves inward. 2. The elastic force of the spring type is not enough. 1. Adjust the position of the weight. 2. Tighten or replace the spring. The valve core does not close automatically after opening.