◆ 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 to carry out the grease injection operation. There are two situations: on the one hand, the amount of grease injection is small, the grease injection is insufficient, and the sealing surface is worn faster due to the lack of lubricant. On the other hand, excessive grease injection causes waste. The reason is that there is no precise calculation of the sealing capacity of different valves according to the type of valve type. The sealing capacity can be calculated according to the size and type of valve, and then the appropriate amount of grease can be injected reasonably

◆ When the valve is greased, the pressure problem is often ignored. During the grease injection operation, the grease injection pressure changes regularly in peaks and valleys. If the pressure is too low, the seal will leak or fail, the pressure will be too high, the grease injection port will be blocked, the lipid in the seal will harden, or the sealing ring will lock up 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 generally 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; On the other hand, grease hardening involves the use of cleaning fluids to repeatedly soften the failed sealing grease and inject new grease to replace it. In addition, the sealing type and sealing material also affect the grease pressure, different sealing forms have different grease pressure, and the grease pressure of hard seal is generally higher than that of soft seal

◆ When the valve is greased, pay attention to the problem of the valve in the switch position. The ball valve is generally in an open state during maintenance, and it is closed for maintenance under special circumstances. Other valves should not be treated as open. The gate valve must be closed during maintenance to ensure that the grease fills the sealing groove along the sealing ring, and if it is opened, the sealing grease will fall directly into the flow channel or valve cavity, resulting in waste

◆ When the valve is greased, the grease injection effect is often ignored. The pressure, amount of grease injection, and switch position are normal during the grease injection operation. However, in order to ensure the grease 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 ram is evenly lubricated

◆ When grease injection, pay attention to the problem of valve body sewage and plug pressure relief. After the valve pressure test, the gas and moisture in the valve cavity of the sealing chamber are pressurized due to the increase in ambient temperature. After grease injection, the air and moisture in the sealing chamber are fully displaced. The pressure of the valve cavity is discharged in time, which also ensures the safety of the valve. After the grease injection is completed, be sure to tighten the blowdown and pressure relief plug to prevent accidents

◆ When injecting grease, pay attention to the problem of uniform grease. In normal grease injection, the grease hole closest to the grease injection port is first greased, then to the low point, and finally to the high point, and the fat is released one by one. If it is not regular or does not have fat, it proves that there is a blockage, and it is cleared in time

◆ When grease injection, it is also necessary to observe the flush problem between the valve diameter and the sealing ring seat. For example, if there is an interference in the opening of a ball valve, the opening limiter can be adjusted inwards to confirm that the diameter is straight and locked. Adjusting the limit should not only pursue the position of the open or closed side, but should be considered as a whole. If the opening is flat and the closing is not in place, it will cause the valve to be closed tightly. In the same way, if the adjustment is in place, the corresponding adjustment of the opening position should also be considered. Ensure the right-angle stroke of the valve

◆ After grease injection, be sure to seal the grease injection mouth. To avoid the entry of impurities or the oxidation of lipids at the grease filling port, the cap should be coated with anti-rust grease to avoid rust. so that it can be applied the next time

◆ When grease injection, it is also necessary to consider the specific problems in the future sequential transportation of oil products. Given the different qualities of diesel and gasoline, the scouring and decomposition capacity of gasoline should be considered. In the future valve operation, when encountering gasoline section operation, timely replenishment of grease to prevent wear

◆ When grease injection, do not ignore the grease injection of the valve stem part. There is a sliding sleeve or packing material at the valve shaft part, which also needs to be kept in a lubricated state to reduce the frictional resistance during operation