Maintenance and use of globe valves

The globe valve in operation should have complete and intact valve components. The bolts on the flange and bracket are indispensable, and the threads should be intact without any looseness. If the fastening nut on the handwheel is found to be loose, it should be tightened in a timely manner to avoid wear on the connection or loss of the handwheel and nameplate. If the handwheel of the shut-off valve is lost, it is not allowed to replace it with an adjustable wrench and should be promptly equipped. The packing gland is not allowed to be skewed or have no pre tightening gap. For globe valves that are prone to contamination by rain, snow, dust, sandstorms, and other pollutants, a protective cover should be installed on the valve stem. The scale on the globe valve should be kept complete, accurate, and clear. The lead seal, cap, pneumatic accessories, etc. of the globe valve should be complete and intact. Do not knock, stand or support heavy objects on the running shut-off valve; Especially for non-metallic valves and cast iron valves, maintenance work during valve grease injection should be strictly prohibited. Professional maintenance work for valves before welding and after production plays a crucial role in serving the production and operation of valves. Correct, orderly, and effective maintenance will protect valves, enable them to function normally, and extend their service life. Valve maintenance work may seem simple, but it is not. There are often overlooked aspects in work.

Firstly, when injecting grease into the shut-off valve, the issue of the amount of grease injected is often overlooked. After grease injection and refueling, the operator selects the valve and grease injection connection method before proceeding with the grease injection operation. There are two situations: on the one hand, the amount of grease injected is insufficient, and the sealing surface wears faster due to the lack of lubricant. On the other hand, excessive fat injection leads to waste. There is no precise calculation of the sealing capacity of different globe valves based on the type of valve. The sealing capacity can be calculated based on the size and type of the shut-off valve, and then an appropriate amount of lubricating grease can be injected reasonably.

Secondly, when injecting grease into the shut-off valve, pressure issues are often overlooked. During the liposuction operation, the liposuction pressure exhibits regular peaks and valleys. Low pressure, seal leakage or failure, high pressure, blockage of grease injection port, hardening of grease inside the seal, or locking of the sealing ring with the valve ball or valve plate. When the grease injection pressure is usually too low, the injected lubricating grease tends to flow into the bottom of the valve chamber, usually occurring in small gate valves. If the injection pressure is too high, on the one hand, check the injection nozzle, and if the grease hole is blocked, determine the situation and replace it; On the other hand, lipid hardening requires the use of cleaning solution to repeatedly soften failed sealing grease and inject new lubricating grease for replacement. In addition, the sealing model and sealing material also affect the grease injection pressure. Different sealing forms have different grease injection pressures, and in general, the grease injection pressure for hard seals is higher than that for soft seals. Ball valves are usually maintained in the open position, and in special circumstances, they may be closed for maintenance. Other valves cannot be treated solely based on their open position. The gate valve must be in the closed state during maintenance to ensure that the lubricating grease fills the sealing groove along the sealing ring. If it is in the open position, the sealing grease will directly fall into the flow channel or valve chamber, causing waste.