Ball valve installation and maintenance

One, ball valve installation
Preparation before installation
1. The pipeline before and after the ball valve is ready. The front and rear pipelines shall be coaxial, and the sealing surfaces of the two flanges shall be parallel. The pipe shall be able to support the weight of the ball valve, otherwise the pipe must be properly supported
2, the valve before and after the pipeline clean, remove the oil, welding slag and all other impurities in the pipeline
3. Check the mark of the ball valve to make sure that the ball valve is in good condition. Open and close the valve several times to verify its normal operation
4, remove the ball valve at both ends of the flange connection on the protection
5, check the valve hole to remove possible dirt, and then clean the valve hole. Even small particles of foreign matter between the seat and the ball may damage the seat sealing surface
The installation
1. Install the valve into the pipeline. Either end of the valve can be installed in the upstream end. Valves driven by handle can be installed anywhere in the pipeline. But ball valves with gearboxes or pneumatic actuators should be installed upright, that is, installed in horizontal pipe, and the driving device is above the pipe
2. Install sealing gasket between valve flange and pipeline flange according to pipeline design requirements
3. The bolts on the flange should be tightened symmetrically, successively and evenly
4. Connect pneumatic pipeline (when pneumatic driver is used)
Check after installation
1. Operate the driver to open and close the ball valve for several times, and it should be flexible without stagnation and astringency, so as to confirm its normal operation
2. Check the sealing performance of the flange joint surface between the pipe and the ball valve according to the design requirements of the pipe
Two, ball valve maintenance
◆ It is necessary to make sure that the pressure has been removed from the upper and downstream pipelines of the ball valve before disassembly and disassembly operation
◆ During decomposition and reassembly, care must be taken to prevent damage to the sealing surface of the parts, especially non-metallic parts. Take out the O-ring and use special tools
The bolts on the flange must be tightened symmetrically, step by step and evenly during assembly
The cleaning agent should be compatible with rubber parts, plastic parts, metal parts and working medium (such as gas) in the ball valve. When the working medium is gas, the metal parts can be cleaned with gasoline (GB484-89). Non-metallic parts shall be cleaned with purified water or alcohol
◆ The decomposed individual parts can be cleaned by soaking. The metal parts that still remain undecomposed non-metallic parts can be scrubbed with a clean, fine and clean silk cloth impregnated with cleaning agent (to avoid fiber shedding and sticking to the parts). Remove grease, dirt, glue and dust that adhere to the wall surface during cleaning
◆ After cleaning, the non-metallic parts should be taken out of the cleaning agent immediately and not soaked for a long time
◆ After cleaning, assembly shall be carried out after the wall surface cleaning agent is volatilized (can be wiped with silk cloth not soaked in cleaning agent), but it shall not be used for a long time, otherwise it will rust and be polluted by dust
◆ New parts also need to be cleaned before assembly
Use grease for lubrication. Grease shall be compatible with metal material, rubber parts, plastic parts and working medium of ball valve. When the working medium is gas, such as T 221 grease may be used. Apply a thin layer of grease on the surface of the sealing groove, a thin layer of grease on the rubber sealing element, and a thin layer of grease on the sealing surface and friction surface of the valve stem
◆ There shall be no contamination, adhesion or retention on the surface of the part or into the inner cavity by metal debris, fiber, grease (except for the prescribed use) dust, other impurities and foreign matter, etc., during assembly