Valve failure and treatment methods

First, the valve leakage:

Reason: 1. Strict closure 2. Combination of surface damage 3. Spool and stem clearance is too large, resulting in spool drooping or contact is not good 4. Poor sealing material or spool jam.

Treatment: 1. Improve operation, reopen or shut down 2. Valve disassembled, valve core, seat sealing surface regrind 3. Adjust the valve stem and valve stem clearance or replace valve 4. Valve disassemble, eliminate jam 5. Replacement Or surfacing seals Second, the filler leakage:

Reason: 1. Filler material is wrong 2. Packing gland is not pressed or pressure-offset 3. The method of adding packing is not 4. Stem surface damage

Processing: 1. The correct choice of packing 2. Check and adjust the packing gland to prevent pressure bias 3. Press the correct method to install packing 4. Repair or replace the valve stem Third, the valve leakage:

Reason: 1. Body blisters or cracks 2. Fracture body repair welding

Treatment: 1. Department of polishing cracks on suspicion, with 4% nitric acid solution etching, if cracks can be displayed 2. Crack at the digging treatment. Fourth, the stem and nut thread with the damaged or broken stem, stem bending:

Reason: 1. Improper operation, the switch force is too large, limit device failure, over torque protection is not moving. 2. Thread with too loose or too tight 3. The operation is too many, the service life is too long

Treatment: 1. Improve the operation, not too much force; check the limit device, check the torque protection device 2. Select the right material, assembly tolerances to meet the requirements 3. Replacement parts 5. Bonded valve cover leakage:

Reason: 1. Bolt tension is not enough or tight 2. Gasket does not meet the requirements or gasket damage 3. Bonding surface is defective

Handling: 1. Tighten the bolts or the gap between the cover flange 2. Replace the gasket 3. Disintegration repair cover seal surface Six, the valve core, seat cracks:

Reason: 1. Bonded surface surfacing poor quality 2. Large temperature difference between the two sides of the valve

Treatment: Crack at the repair welding, according to the provisions of heat treatment, car light, and grinding. Seven, valve stem and valve stem from the switch failure caused:

Reason: 1. Improper repairs 2. The valve core and the stem is corroded 3. The switch force is too large, resulting in the valve core and the stem is damaged at the junction 4. Spool washer relief, connecting parts wear and tear

Treatment: 1. Maintenance inspection attention 2. Replace the corrosion-resistant door rod 3. The operation is not strong switch, or can not be fully open to continue to open the valve inlet pump 4. Check to replace the damaged spare parts VIII. Valve stem lifting ineffective or switch Do not move:

Reason: 1. cold too closed too tight after the heat expansion or close too tight 2. packing too tight pressure 3. Stem clearance is too small and die 4. Stem and nut mating too tight, or With the wire buckle damage 5. Packing gland pressure partial 6. Door bending 7. Medium temperature is too high, poor lubrication, the valve stem serious corrosion

Treatment: 1. After heating the valve body slowly test force or open enough and close again when the tight. 2. Slightly loose packing gland after the test open 3. Appropriate to increase the stem gap 4. Replace the stem and nut 5. To re-adjust the packing gland bolts 6. Straighten the door or replacement 7. Door using pure graphite Powder lubricant