First, the valve body leakage: the reason: 1. The valve body has blisters or cracks; 2. The valve body is cracked during repair welding deal with: 1. Polish the suspected crack and etch it with 4% nitric acid solution. If there is crack, it can be displayed; 2. Excavation treatment of the crack. Second, the valve stem and its mating thread are damaged or the stem tip is broken and the stem is bent: the reason: 1. Improper operation, excessive force on the switch, failure of the limit device, and over-torque protection. ; 2. The thread is too loose or too tight; 3. Too many operations and long service life deal with: 1. Improve the operation, the force is too large; check the limit device and check the over-torque protection device; 2. Select the appropriate material and the assembly tolerances meet the requirements; 3. Replacement of spare parts Third, the bonnet combined surface leakage: Reason: 1. The bolt tightening force is not enough or tightly biased; 2. The gasket does not meet the requirements or the gasket is damaged; 3. The joint surface is defective deal with: 1. Retighten the bolts or make the door flange flanges consistent; 2. Replace the gasket; 3. Disassemble the door cover sealing surface Fourth, the valve leakage: the reason: 1. Closed is not strict; 2. Joint surface damage; 3. The gap between the valve core and the valve stem is too large, causing the valve core to sag or contact poorly; 4. Poor sealing material or valve cartridge jam. deal with: 1. Improve the operation, re-open or close; 2. The valve is disassembled, and the sealing surface of the valve core and the valve seat is re-ground; 3. Adjust the gap between the valve plug and the stem or replace the valve flap; 4. The valve is disintegrated to eliminate the jam; 5. Re-replace or weld the seal ring 5. The valve core is separated from the valve stem, causing the switch to malfunction: the reason: 1. improper repair; 2. The joint between the valve core and the valve stem is corroded; 3. The force of the switch is too large, causing the joint between the valve core and the valve stem to be damaged; 4. The spool retaining washer is loose and the joint is worn. deal with: 1. Pay attention to inspection during maintenance; 2. Replace the door rod of corrosion resistant material; 3. Operation is not strong switch, or can not continue to open the valve after full opening; 4. Check and replace damaged spare parts Sixth, the valve core and valve seat have cracks: the reason: 1. The quality of the joint surface welding is poor; 2. The temperature difference between the two sides of the valve is large: Repair welding with cracks, heat treatment according to regulations, light and grind. 7. The valve stem does not move up or down or the switch does not move: the reason: 1. When the cold state is closed, it is too tight to be swollen after being heated or too tight after being fully opened; 2. The packing is pressed too tightly; 3. The valve stem clearance is too small to swell; 4. The valve stem and the nut are too tightly matched, or the threaded fastener is damaged; 5. Packing gland pressure deviation; 6. The door stem is bent; 7. The medium temperature is too high, the lubrication is poor, and the valve stem is seriously rusted. deal with: 1. After heating the valve body, slowly test it with force or open it tightly and then close it slightly; 2. After a little loose packing, try to open; 3. Appropriately increase the valve stem clearance; 4. Replace the valve stem and the nut; 5. Re-adjust the packing gland bolts; 6. Straighten the door lever or replace it; 7. The door rod uses pure graphite powder as a lubricant Eight, filler leakage: the reason: 1. The filler material is incorrect; 2. The packing gland is not pressed or biased; 3. The method of adding packing is wrong; 4. Stem surface damage deal with: 1. Correct selection of fillers; 2. Check and adjust the packing gland to prevent pressure deviation; 3. Add packing according to the correct method; 4. Repair or replace the valve stem Transshipment System,Movement Flexibility Use,Limited Area Can Wokring,Customized Lay and Size Changzhou Fuku Precision Machinery Co., Ltd. , https://www.cfpmworkbench.com