Installation and maintenance of ball valves

I. Ball Valve Installation

Pre-installation Preparations

1. The pipelines before and after the ball valve are ready. The pipelines should be coaxial, and the sealing surfaces of the two flanges should be parallel. The pipeline should be able to withstand the weight of the ball valve; otherwise, appropriate supports must be provided on the pipeline.

2. Blow the pipelines before and after the valve clean to remove oil stains, welding slag, and all other impurities.

3. Check the markings on the ball valve to ensure it is intact and undamaged. Open and close the valve several times to confirm that it is working properly.

4. Remove the protective parts from the connecting flanges at both ends of the ball valve.

5. Inspect the valve port and remove any possible debris, then clean the valve port. Even tiny particles of foreign matter between the valve seat and the ball can damage the valve seat sealing surface.

Installation

1. Install the valve onto the pipeline. Either end of the valve can be installed on the upstream side. Handwheel-operated valves can be installed at any position on the pipeline. However, ball valves with gearboxes or pneumatic actuators should be installed vertically, i.e., installed on horizontal pipelines with the actuator above the pipeline.

2. Install sealing gaskets between the valve flanges and the pipeline flanges according to the pipeline design requirements.

3. The bolts on the flanges should be tightened symmetrically, sequentially, and evenly.

4. Connect the pneumatic pipeline (when using a pneumatic actuator).

Post-installation Inspection

1. Operate the actuator to open and close the ball valve several times. It should be flexible and without any sticking, confirming that it is working properly.

2. Check the sealing performance of the flange joint between the pipeline and the ball valve according to the pipeline design requirements.

II. Ball Valve Maintenance

◆ Pressure in the pipelines upstream and downstream of the ball valve must be relieved before disassembly and decomposition operations can be performed.

◆ During disassembly and reassembly, care must be taken to prevent damage to the sealing surfaces of the parts, especially non-metallic parts. When removing O-rings, use special tools.

◆ When assembling, the bolts on the flanges must be tightened symmetrically, gradually, and evenly.

◆ The cleaning agent should be compatible with the rubber parts, plastic parts, metal parts, and working medium (e.g., fuel gas) in the ball valve. When the working medium is fuel gas, gasoline (GB484-89) can be used to clean metal parts. Non-metallic parts can be cleaned with pure water or alcohol.

◆ Individual disassembled parts can be cleaned by immersion. Metal parts with remaining non-metallic parts that have not been disassembled can be cleaned with a clean, fine cloth soaked in cleaning agent (to avoid fiber shedding and sticking to the parts). During cleaning, remove all oil, dirt, adhesive residue, dust, etc., adhering to the wall surface.

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

◆ After cleaning, wait for the cleaning agent on the cleaned surface to evaporate (a cloth not soaked in cleaning agent can be used to wipe) before assembly, but do not leave it for a long time, otherwise it will rust and be contaminated by dust.

◆ New parts should also be cleaned before assembly.

◆ Lubricate with grease. The grease should be compatible with the ball valve metal materials, rubber parts, plastic parts, and working medium. When the working medium is fuel gas, grease such as Te221 can be used. Apply a thin layer of grease to the surface of the sealing ring groove, a thin layer of grease to the rubber seal, and a thin layer of grease to the sealing surface and friction surface of the stem.

◆ During assembly, metal shavings, fibers, grease (except for specified use), dust, and other impurities and foreign matter are not allowed to contaminate, adhere to, or remain on the surface of the parts or enter the cavity.