For gate valves, you must not only know how to install and maintain them, but also how to operate them.
When opening and closing a gate valve, the force should be smooth and steady, avoiding any impact. Some high-pressure gate valves designed for impact opening and closing have components that are designed to withstand different impact forces than ordinary gate valves.
After the gate valve is fully open, the handwheel should be turned back slightly to tighten the threads and prevent loosening and damage.
When the pipeline is first used, there may be a lot of dirt inside. The gate valve can be slightly opened to allow the high-speed flow of the medium to flush it away, then gently close it (do not close it quickly or abruptly to prevent residual impurities from damaging the sealing surface). Repeat this process several times to clean away the dirt before putting it into normal operation.
Normal open gate valves may have dirt adhering to the sealing surface. When closing, flush it clean using the above method before fully closing it.
If the handwheel or handle is damaged or lost, it should be replaced immediately. Do not use an adjustable wrench as a substitute, as this may damage the valve stem, causing malfunctions and potentially accidents during production.
For some media, after the gate valve cools down after closure, the valve components contract. The operator should then close the valve again at an appropriate time to ensure no gaps remain on the sealing surface. Otherwise, the medium will flow through these gaps at high speed, easily eroding the sealing surface.
During operation, if excessive effort is required, the cause should be analyzed. If the packing is too tight, it can be loosened appropriately. If the valve stem is misaligned, personnel should be notified for repair. Some gate valves, when closed, experience thermal expansion of the closing element, making opening difficult. If opening is necessary at this time, the valve cover threads can be loosened by half a turn to one turn to relieve valve stem stress, and then the handwheel can be turned.