Maintenance of PPSU pipe fittings valve grease injection: When the valve is greased, the problem of grease injection is often ignored. After the grease injection gun is refueled, the operator selects the valve and the grease injection connection method, and then performs the grease injection operation. There are two situations: on the one hand, the amount of grease injection is small and the grease injection is insufficient, and the sealing surface wears quickly due to the lack of lubricant. On the other hand, excessive grease injection results in waste. The reason is that there is no precise calculation of the sealing capacity of different valves according to the valve type category. The sealing capacity can be calculated according to the valve size and type, and then a reasonable amount of grease can be injected. Pressure issues are often overlooked when valves are greased. During the grease injection operation, the grease injection pressure changes regularly with 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 sealing inner grease is hardened, or the sealing ring is locked with the valve ball and valve plate. Usually, when the grease injection pressure is too low, the injected grease mostly flows into the bottom of the valve cavity, which usually occurs in small gate valves. If the grease injection pressure is too high, on the one hand, check the grease injection nozzle, and replace it if the grease hole is blocked. . In addition, the sealing type and sealing material also affect the grease injection pressure. Different sealing forms have different grease injection pressures. Generally, the grease injection pressure of hard seals is higher than that of soft seals. When injecting grease into the valve, pay attention to the problem that the valve is in the switch position. The ball valve is generally in the open position during maintenance, and in special cases, it is selected to be closed for maintenance. Other valves can not be regarded as open position. The gate valve must be closed during maintenance to ensure that the grease fills the sealing groove along the sealing ring. If it is opened, the sealing grease will fall directly into the flow channel or valve cavity, causing waste. When the valve is greased, the effect of grease injection is often ignored. During the grease injection operation, the pressure, grease injection volume, and switch position are all normal. However, in order to ensure the grease injection effect of the valve, it is sometimes necessary to open or close the valve, check the lubrication effect, and confirm that the surface of the valve ball or gate plate is evenly lubricated. When injecting grease, pay attention to the valve body blowdown and wire plug pressure relief problems. After the valve pressing test, the gas and moisture in the valve cavity of the sealing cavity will increase due to the increase of the ambient temperature. When injecting grease, it is necessary to discharge the sewage and release the pressure first, so as to facilitate the smooth progress of the grease injection. The air and moisture in the sealed cavity are fully replaced after grease injection. The valve cavity pressure is released in time, which also ensures the safety of the valve. After the grease injection, be sure to tighten the drain and pressure relief plugs to prevent accidents.
