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Maintenance precautions for ball valve


In order to make the ball valve have a long service life and maintenance-free period, in addition to normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data, the following factors must be paid attention to:

1. When the ball valve is closed, there is still pressurized fluid inside the valve body.

2. Before repairing the ball valve, relieve the pipeline pressure and keep the valve in the open position.

3. Before maintenance of the ball valve, disconnect the power supply or gas source.

4. Before maintenance, disengage the actuator from the bracket.

5. It is necessary to first find out that the pressure of the upstream and downstream pipelines of the ball valve has been relieved, and then the disassembly and decomposition operation can be carried out.

6. Be careful to prevent damage to the sealing surface of parts, especially non-metallic parts, when disassembling and reassembling. Special tools should be used when taking out the O-ring.

7. When the ball valve is assembled, the bolts on the flange should be tightened symmetrically, gradually and evenly.

8. The cleaning agent should be compatible with the rubber parts, plastic parts, metal parts and working medium (such as gas) in the ball valve. When the working medium is gas, gasoline can be used to clean metal parts. Clean non-metallic parts with pure water or alcohol.

9. The decomposed single parts can be cleaned by dipping. Metal parts with undecomposed non-metal parts can be scrubbed with a clean and fine silk cloth impregnated with cleaning agent (to prevent the fibers from falling off and adhering to the parts). When cleaning, all grease, dirt, glue, dust, etc. adhering to the wall must be removed.

10. Non-metal parts should be removed from the cleaning agent immediately after cleaning, and should not be soaked for a long time.

11. After cleaning, it needs to be assembled after the cleaning agent on the wall to be washed has volatilized (it can be wiped with a silk cloth that has not been soaked in the cleaning agent), but it should not be put on hold for a long time, otherwise it will rust and be polluted by dust.

12. New parts also need to be cleaned before assembly.

13. Lubricate with grease. Grease should be compatible with ball valve metal materials, rubber parts, plastic parts and working medium. When the working medium is gas, for example, special 221 grease can be used. Apply a thin layer of grease on the surface of the seal installation groove, apply a thin layer of grease on the rubber seal, and apply a thin layer of grease on the sealing surface and friction surface of the valve stem.

14 During assembly, no metal chips, fibers, grease (except those specified for use), dust, and other impurities, foreign objects, etc. shall be allowed to contaminate, adhere or stay on the surface of the parts or enter the inner cavity.

1) The packing should be locked again. If there is micro-leakage at the packing, the stem nut should be tightened again. Note: Do not lock too tightly, usually 1/4 turn to 1 turn, the leakage will stop.

2), replace the valve seat and seal.

A), disassembly

Put the valve in the half-open position, flush and remove the dangerous substances that may exist inside and outside the valve body. Close the ball valve, remove the connecting bolts and nuts on both flanges, and then completely remove the valve from the pipeline.

Disassemble the drive device in sequence - actuator, connecting bracket, lock washer, stem nut, butterfly shrapnel, glam, wear-resistant sheet, stem packing. Remove the body cover connecting bolts and nuts, separate the bonnet from the body, and remove the bonnet gasket.

Make sure the ball valve is in the "closed" position, which allows it to be easily removed from the valve body and then the valve seat. Gently push the valve stem downward from the hole in the valve body until it is completely removed, and then take out the O-ring and the packing under the valve stem.

Note: Please operate with caution to avoid scratching the surface of the valve stem and the sealing part of the valve body stuffing box.

B), reassembly

Clean and inspect the dismantled parts. It is strongly recommended to replace the valve seat and valve cover gasket and other seals with a spare parts kit. Assemble in the reverse order of disassembly.

With the specified torque, cross-lock the flange connection bolts. Tighten the stem nut with the specified torque.

After installing the actuator, input the corresponding signal to drive the valve core to rotate by rotating the valve stem, so that the valve can be opened or closed. If possible, perform a pressure tightness test and performance test on the valve according to the relevant standards before reinstalling the pipeline.