The core of valve installation and maintenance lies in strictly following flow direction markings, ensuring stress free connections, maintaining clean sealing surfaces, and regularly lubricating and rust preventing. Incorrect operation can easily lead to seal failure, valve stem jamming, or medium leakage.
1、 Key installation precautions
Verification and Inspection
Before installation, check whether the model, pressure rating, material, and flow arrow are consistent with the design requirements.
Check the valve body for cracks and deformation, remove impurities (welding slag, iron filings) inside the valve, and strictly prohibit installation with impurities to avoid scratching the sealing surface.
Fragile material valves (such as cast iron) should be handled with care to avoid impact.
Direction and posture
Strictly follow the flow direction: globe valves, check valves, pressure reducing valves, etc. must have directionality, and the arrow on the valve body must be consistent with the flow direction of the medium; Globe valves typically require a "low in, high out" condition.
Installation posture: The pressure reducing valve needs to be installed upright; Bright stem gate valves should not be installed underground to prevent valve stem corrosion; The actuator (electric/pneumatic) should prioritize vertical upward movement and must not be inverted to prevent water ingress or grease loss.
Space reservation: The height of the handwheel or operating mechanism above the ground should be about 1.2 meters, and sufficient space should be reserved for maintenance and disassembly.
Connection process
Stress free installation: When connecting flanges, the end faces must be parallel, and the bolts must be symmetrically and evenly tightened. Forced alignment is strictly prohibited to prevent the valve body from cracking under stress.
Welding protection: When welding valves, the valve should be in a slightly open state and wrapped in a damp cloth to dissipate heat and prevent damage to the sealing components due to high temperatures.
Lifting specifications: The rope should be tied to the flange or valve body, and it is strictly prohibited to tie it to the handwheel or valve stem.
2、 Key points of daily maintenance and upkeep
Cleaning and lubrication
Regularly clean the dust and rust on the surface of the valve body to maintain a clean appearance.
Key lubrication: Regularly add butter or molybdenum disulfide to the valve stem threads and transmission gears to prevent thread biting; Valves that are not frequently operated should also have their handwheel turned regularly.
It is recommended to install rain covers on outdoor valves to prevent rainwater from corroding electrical components or causing rust.
Sealing and fastening
Packing inspection: If slight leakage is found in the packing box, the gland bolts can be evenly tightened; If the leakage is severe and the same specification of packing needs to be replaced, the cut should be staggered 180 degrees for filling.
Heat tightening treatment: High temperature valves (>200 ℃) need to be re tightened (hot tightened) due to bolt expansion after heating operation to prevent hot leakage.
Anti freezing emptying: Water valves that are not used for a long time in winter must be drained of internal accumulated water to prevent freezing and cracking.
Operation and storage
Avoid violence: Apply even force when opening and closing, and do not forcefully pull in case of jamming. The cause should be identified.
Storage requirements: The spare valve should be stored in a dry and ventilated place, with sealed and dust-proof channels at both ends. Regular rust prevention treatment is required for long-term storage.
Regular testing: Key valves should undergo regular opening and closing tests and sealing checks to ensure flexible and reliable operation.
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