◆The purpose of storage and maintenance is to prevent damage to the valve during storage, or reduce quality. In fact, improper storage is one of the important reasons for valve damage.
◆Valves should be kept in an orderly manner. Small valves should be placed on shelves. Large valves can be arranged neatly on the floor of the warehouse. They should not be stacked in disorder, and flanges should not be connected to the surface. Touch the ground. This is not only for aesthetics, but mainly to protect the valve from being damaged.
◆Due to improper storage and handling, the hand wheel is broken, the valve stem is knocked, the fixing nut of the hand wheel and the valve stem is loose and lost, etc. These unnecessary losses should be Avoid
◆ Asbestos packing should be taken out for valves that will not be used in a short period of time to avoid electrochemical corrosion and damage to the valve stem
◆ Valves that have just entered the warehouse should be inspected. If rain or dirt enters during transportation, Wipe clean, and then store it
◆The inlet and outlet of the valve should be sealed with wax paper or plastic sheet to prevent dirt from getting in.
◆The processing surface of the valve that can rust in the atmosphere should be coated with anti-rust oil to protect it.
◆Place the outdoor valve , Must be covered with rain-proof and dust-proof items such as linoleum or tarpaulin. The warehouse where the valve is stored should be kept clean and dry
Use and maintenance
◆The purpose of use and maintenance is to extend the life of the valve and ensure reliable opening and closing.
◆Stem thread, often friction with the stem nut, should be coated with a little yellow dry oil, molybdenum disulfide or graphite powder for lubrication.
◆Infrequent opening and closing For valves, turn the handwheel regularly to add lubricant to the thread of the valve stem to prevent it from being bitten.
◆Outdoor valves should be covered with a protective cover to prevent rain, snow, dust and rust
◆If the valve system is mechanically waiting, Add lubricating oil to the gearbox on time. It is
necessary to keep the valve clean. It is
necessary to frequently check and maintain the integrity of the other parts of the valve. If the fixing nut of the handwheel falls off, it must be fully equipped and cannot be used properly, otherwise it will grind the upper part of the valve stem, and gradually lose the reliability of cooperation, or even fail to
operate. Do not rely on the valve to support other heavy objects, and do not stand on the valve.
◆ The valve stem, especially the threaded part, should be wiped frequently, and the lubricant that has been soiled by dust should be replaced with a new one, because the dust contains hard debris, which is easy to wear the thread and the surface of the valve stem, which affects the service life
◆The packing is directly related to the key seals that leak when the valve is switched on and off. If the packing fails and causes leakage, the valve will also fail, especially the valve of the urea pipeline, because the temperature is relatively high, corrosion is more harmful, and the packing is prone to aging . Enhancing maintenance can extend the life of the packing. When the
valve leaves the factory, in order to ensure the elasticity of the packing, it is generally subject to the static pressure test without leakage. After the valve is installed in the pipeline, extravasation may occur due to factors such as temperature. At this time, the nuts on both sides of the packing gland should be tightened in time, as long as there is no leakage, and no extravasation will occur in the future. Tighten it to prevent the packing from losing its elasticity and sealing performance.
◆Some valve packings are filled with molybdenum disulfide grease. After several months of use, the corresponding lubricating grease should be added in time. When the packing needs to be supplemented, the corresponding grease should be added in time Packing to ensure its sealing performance
Transmission parts maintenance
◆During the opening and closing of the valve, the lubricating grease originally added will continue to be lost, coupled with the effects of temperature, corrosion and other factors, the lubricating oil will also continue to dry up. Therefore, the transmission part of the valve should be checked frequently, and when it is found that there is a lack of oil, it should be filled in time to prevent the increase in wear due to lack of lubricant, resulting in inflexible transmission or jamming failure
Maintenance during valve grease injection
◆When the valve is injecting grease, the problem of the amount of grease injection is often ignored. After the grease injection gun is refueled, the operator selects the valve and grease injection connection mode, 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 faster due to lack of lubricant. On the other hand, excessive fat injection causes waste. The reason is that there is no accurate calculation of the sealing capacity of different valves according to the valve type category. The sealing capacity can be calculated based on the valve size and type, and then a reasonable amount of grease can be injected. When the
valve is greased, the pressure problem is often ignored. During the fat injection operation, the fat injection pressure changes regularly between peaks and valleys. If 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 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, if the grease hole is blocked, replace it; on the other hand, if the grease is hardened, use a cleaning fluid to repeatedly soften the failed sealing grease and inject new grease to replace it. . In addition, the type and material of the seal also affect the grease injection pressure. Different seal forms have different grease injection pressures. Generally, the grease injection pressure for hard seals is higher than that for soft seals.
◆When grease injection on valves, pay attention to the problem of the valve at the switch position. . The ball valve is generally in the open position during maintenance. In special circumstances, it is selected to close for maintenance. Other valves cannot be treated as open positions. The gate valve must be closed during maintenance to ensure that the grease fills the sealing groove along the sealing ring. If it is open, the sealing grease will directly fall into the flow path or valve cavity, causing waste. When the
valve is greased, the grease injection effect is often ignored problem. During the grease injection operation, the pressure, grease injection volume, and switch position are all normal. However, in order to ensure the effect of valve grease injection, it is sometimes necessary to open or close the valve to check the lubrication effect to confirm that the surface of the valve ball or gate is evenly lubricated. When grease
injection, pay attention to the problem of valve body drainage and plug pressure relief. After the valve pressure test, the gas and moisture in the valve cavity of the sealed cavity will increase in pressure due to the increase in ambient temperature. When grease is injected, the pressure must be discharged first to facilitate the smooth progress of the grease injection. After the grease is injected, the air and moisture in the sealed cavity are fully replaced. Relieve the pressure of the valve cavity in time, which also guarantees the safety of the valve. After the grease injection, be sure to tighten the drain and pressure relief plug to prevent accidents
◆When injecting grease, pay attention to the problem of uniform grease output. In normal grease injection, the grease outlet closest to the grease injection port first discharges the grease, then to the low point, and finally to the high point, and the grease is discharged one by one. If you do not follow the rules or do not produce grease, it proves that there is a blockage, and clear it in time.
◆When filling grease, also observe the problem of the valve diameter and the seal ring seat being flush. For example, for ball valves, if there is an open position interference, the open position limiter can be adjusted inward to confirm that the diameter is straight and locked. Adjusting the limit can not only pursue the opening or closing position, but should be considered as a whole. If the opening position is flush and the closing position is not in place, the valve will not close tightly. In the same way, if the adjustment is in place, the adjustment of the open position should also be considered. Ensure the right-angle stroke of the valve
◆After grease injection, be sure to seal the grease injection port. Avoid the entry of impurities, or the oxidation of lipids at the grease injection port, and the cover should be coated with anti-rust grease to avoid rust. In order to apply the
grease injection in the next operation, it is also necessary to consider the specific treatment of specific problems in the sequential transportation of oil in the future. In view of the different qualities of diesel and gasoline, the scour and decomposition ability of gasoline should be considered. In the future valve operation, when encountering gasoline segment operations, replenish grease in time to prevent wear and tear
. Do not ignore the grease injection at the valve stem when grease injection. There is a sliding sleeve or packing on the valve shaft, which also needs to be kept lubricated to reduce the frictional resistance during operation. If lubrication cannot be ensured, the torque will increase during electric operation and wear parts will be difficult to switch during manual operation.
◆Some ball valve bodies It is marked with an arrow. If there is no English FIOW writing, it is the direction of action of the seal seat, not as a reference for the flow direction of the medium, and the valve self-venting direction is opposite. Under normal circumstances, the double-seat sealed ball valve has two-way flow.
When maintaining the valve, pay attention to the water ingress in the electric head and its transmission mechanism. Especially in the rainy season the infiltration of rainwater. One is to rust the transmission mechanism or the transmission shaft sleeve, and the other is to freeze in winter. Cause the torque to be too large when the electric valve is operated, and damage to the transmission components will cause the motor to be unloaded or the over-torque protection will be tripped and electric operation cannot be realized. The transmission parts are damaged, and manual operation cannot be performed. After the over-torque protection is activated, manual operation also cannot be switched. Forcible operation will damage the internal alloy parts.
Valve maintenance must be treated with a scientific attitude in order to achieve the desired effect and application purpose of valve maintenance. In order to make production run normally, reduce downtime, and increase economic benefits, these three points must be done well in terms of valves.
1. Correct selection of valves is the basis
2. Correct use of valves is the most critical 3. Correct maintenance is the guarantee