The professional maintenance work of the valve before and before production and after production, plays a vital role in serving the valve in production and operation. Correct, orderly and effective maintenance will protect the valve, enable the valve to function normally and prolong the use of the valve. life. Valve maintenance may seem simple, but it is not. There are often neglected aspects of work.
First, when the valve is filled with grease, the problem of the amount of grease is often ignored. After the grease gun is refueled, the operator selects the valve and grease connection mode, and then performs the grease injection operation. There are two situations: On the one hand, the amount of grease injected is small, and the amount of grease injected is insufficient, and the sealing surface is accelerated due to lack of lubricant. On the other hand, excessive fat injection causes waste. The reason is that there is no accurate calculation of different valve sealing capacities according to the type of valve. The sealing capacity can be calculated based on the DIN globe valve size and type, and then a reasonable amount of grease can be injected.
Second, the pressure problem is often ignored when the valve is filled with grease. During the fat injection operation, the fat injection pressure changed regularly in peaks and valleys. The pressure is too low, the seal leaks or fails, the pressure is too high, the grease injection port is blocked, the grease in the seal is hardened, or the seal ring is locked with the valve ball and valve plate. Usually when the grease injection pressure is too low, the injected grease flows into the bottom of the valve cavity, which usually occurs in small gate valves. The grease injection pressure is too high. On the one hand, check the grease injection nozzle, and replace it if the fat hole is blocked; on the other hand, if the grease is hardened, use a cleaning liquid, repeatedly soften the failed sealing grease, and inject new grease to replace it. In addition, the seal type and seal material also affect the grease injection pressure. Different seal types have different grease injection pressures. Generally, the hard seal grease injection pressure is higher than the soft seal.
Third, pay attention to the problem of the valve in the switch position when filling the valve with grease. The ball valve is generally in the open position during maintenance. In special cases, the valve is closed for maintenance. Other valves cannot be treated in the same way. The gate valve must be closed during maintenance to ensure that the grease fills the sealing groove along the seal ring. If it is open, the seal grease will fall directly into the flow channel or valve cavity, causing waste.
Fourth, when the valve is filled with grease, the problem of the effect of fat filling is often ignored. During the fat injection operation, the pressure, the amount of fat injection, and the switch position are normal. However, in order to ensure the grease injection effect of the valve, it is sometimes necessary to open or close the valve and check the lubrication effect to confirm that the surface of the valve ball or the gate is evenly lubricated.
Fifth, pay attention to the problems of valve body drainage and wire plug pressure relief when injecting grease. After the butterfly valve pressure test, the gas and moisture in the sealed chamber valve cavity are increased due to the increase in ambient temperature. When the grease is injected, the drainage and pressure should be performed first to facilitate the smooth operation of the grease injection. The air and moisture in the sealed cavity are fully replaced after the grease injection. Releasing the valve cavity pressure in time also ensures the safety of the valve. After the end of the greasing, be sure to tighten the drain and pressure relief plugs to prevent accidents.