How to install and repair ball valves?

Ball valves are essential components in fluid control systems, providing reliable shut-off and control functions. Proper installation and regular maintenance are crucial to ensuring the longevity and optimal performance of ball valves. Here is a comprehensive guide for the installation and maintenance of ball valves.

Preparation Before Installation

• The pipelines before and after the ball valve are ready. The front and rear pipelines should be coaxial, and the sealing faces of the two flanges should be parallel. The pipeline should be able to support the weight of the ball valve; otherwise, proper support must be provided on the pipeline.

• Clean the front and rear pipelines, removing oil, welding slag, and any other impurities inside the pipes.

• Check the identification of the ball valve to ensure it is in good condition. Operate the valve fully open and fully closed several times to confirm its normal operation.

• Remove the protective covers on the flanges at both ends of the ball valve.

• Check the valve orifice for any debris, and then clean the valve orifice. Even tiny particles between the valve seat and ball can damage the valve seat sealing surface.

Installation

• Install the valve on the pipeline; either end of the valve can be installed on the upstream side. Valves with handle drives can be installed at any position on the pipeline. However, ball valves with gearboxes or pneumatic actuators should be installed upright, on horizontal pipelines, with the drive unit above the pipeline.

• Install sealing gaskets between the valve flange and the pipeline flange according to the pipeline design requirements.

• Tighten the bolts on the flange symmetrically, gradually, and evenly.

• Connect pneumatic lines (when using a pneumatic actuator).

Post-Installation Checks

• Operate the actuator to open and close the ball valve several times, ensuring smooth and unimpeded operation to confirm its normal function.

• Perform a sealing performance check on the flange joint surface between the pipeline and the ball valve according to the pipeline design requirements.

Ball Valve Maintenance

• Ensure that the upstream and downstream pipelines of the ball valve have been depressurized before performing disassembly operations.

• Exercise caution to prevent damage to the sealing surfaces of parts, especially non-metallic parts, during disassembly and reassembly. Use specialized tools when removing O-rings.

• When assembling, bolts on the flange must be tightened symmetrically, gradually, and evenly.

• The cleaning agent should be compatible with rubber parts, plastic parts, metal parts, and working media (e.g., gas). When working with gas, use gasoline (GB484-89) to clean metal parts. Clean non-metallic parts with clean water or alcohol.

• Individual parts that have been disassembled can be cleaned by immersion. Metal parts with non-disassembled non-metallic parts can be wiped with a clean, fine, impregnated cloth (to prevent fiber shedding from adhering to the parts). Remove all grease, dirt, adhesive, dust, and other contaminants from the surface during cleaning.

• Non-metallic parts should be removed from the cleaning agent immediately after cleaning and should not be immersed for an extended period.

• After cleaning, assemble the parts once the cleaning agent has evaporated (use a cloth with non-soaked cleaning agent to wipe). However, do not leave them idle for an extended period to avoid rusting and contamination by dust.

• New parts should be cleaned before assembly.

• Use lubricating grease. The grease should be compatible with the metal materials of the ball valve, rubber parts, plastic parts, and working media. When working with gas, use, for example, special grease such as Type 221. Apply a thin layer of grease on the surface of the sealing groove, a thin layer on the rubber sealing surface, and a thin layer on the sealing surface and friction surface of the valve stem.

• During assembly, no metal debris, fibers, grease (except for specified use), dust, or other pollutants, impurities, foreign objects, etc., are allowed to contaminate, adhere, or remain on the surface of the parts or enter the cavity.