How to maintain the valve

How to maintain the valve

Valves, like other mechanical products, also require maintenance. This work is done well to extend the service life of the valve. The maintenance of the valve will be described below.

 

Custody maintenance

â—† The purpose of storage and maintenance is to prevent the valve from being damaged during storage or to reduce the quality. In fact, improper storage is one of the important reasons for valve damage.

â—† Valve storage, should be well organized, small valves placed on the shelves, large valves can be neatly arranged on the floor of the warehouse, can not be messed up, do not let the flange connection surface contact the ground. This is not only for the sake of beauty, but mainly to protect the valve from damage.

â—† Because of improper storage and handling, the hand wheel is broken, the valve stem is bumped, the fixing nut of the hand wheel and the valve stem is loose, etc. These unnecessary losses should be avoided.

â—† For valves that are not used for a short period of time, asbestos filler should be taken to avoid electrochemical corrosion and damage to the valve stem.

â—† Check the valve that has just entered the warehouse. If rain or dirt is in the process of transportation, wipe it clean and store it again.

â—†The inlet and outlet of the valve should be sealed with wax paper or plastic sheet to prevent getting dirty.

â—† Protect the surface of the valve that can rust in the atmosphere with anti-rust oil.

â—†When placing the outdoor valve, it must be covered with rainproof or dustproof items such as linoleum or crepe. Store the valve in a warehouse that is clean and dry

 

Use maintenance

â—† The purpose of maintenance is to extend the life of the valve and ensure reliable opening and closing.

â—†The stem thread is often rubbed against the stem nut. It should be coated with a little yellow dry oil, molybdenum disulfide or graphite powder to lubricate.

â—† Valves that do not open and close frequently, also turn the handwheel regularly, add lubricant to the stem thread to prevent biting

â—† Outdoor valve, protect the valve stem from rain, snow, dust and dirt

â—† If the valve is mechanically moving, add lubricant to the gearbox on time.

â—† Always keep the valve clean

â—† Always check and maintain the integrity of the valve components. If the fixing nut of the hand wheel falls off, it must be matched and cannot be used. Otherwise, the square of the upper part of the valve stem will be ground, and the reliability of the fitting will be gradually lost, and even the operation cannot be started.

â—† Do not rely on the valve to support other heavy objects, do not stand on the valve

â—†The valve stem, especially the threaded part, should be wiped frequently. The lubricant that has been soiled by dust should be replaced with new ones. Because the dust contains hard materials, it is easy to wear the thread and the stem surface, which affects the service life.

 

Filler maintenance

â—†The filler is directly related to the key seal of the external leakage when the valve is switched. If the filler fails, the leakage is caused, and the valve is equal to the failure. Especially the valve of the urea pipeline is more susceptible to corrosion due to its higher temperature, and the filler is prone to aging. . Enhanced maintenance can extend the life of the filler

 

â—†When the valve is shipped from the factory, in order to ensure the elasticity of the packing, the static pressure test is generally not allowed to leak. After the valve is installed in the pipeline, due to temperature and other factors, extravasation may occur. At this time, the nut on both sides of the packing gland should be tightened in time, as long as it does not leak, and then the extravasation will be tightened again. Tight to avoid loss of elasticity and loss of sealing performance

 

â—† Some valve packings are filled with molybdenum disulfide lubricating paste. When used for several months, the corresponding lubricating grease should be added in time. When the filler needs to be added, the corresponding packing should be added in time to ensure its sealing performance.

 

Transmission part maintenance

â—†When the valve is in the process of switching, the original added lubricating grease will be continuously lost. Together with the effects of temperature and corrosion, the lubricating oil will continue to dry up. Therefore, the transmission part of the valve should be checked frequently, and it is found that the lack of oil should be replenished in time to prevent the increase of wear due to the lack of lubricant, resulting in inflexible transmission or failure of the casing.

 

Maintenance of valve grease filling

â—† When the valve is greased, the problem of the amount of grease is often ignored. After the grease gun is refueled, the operator selects the valve and the grease injection method to perform the grease filling operation. There are two cases: on the one hand, the amount of grease is less than that of the grease, and the sealing surface is accelerated by the lack of lubricant. On the other hand, excessive fat injection causes waste. There is no accurate calculation of the different valve sealing capacities based on the valve type category. The sealing capacity can be calculated in terms of valve size and type, and a proper amount of grease can be injected reasonably.

 

â—† When the valve is greased, the pressure problem is often ignored. During the grease injection operation, the grease injection pressure changes regularly in the 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 seal grease hardens or the seal ring and the valve ball and the valve plate are locked. Usually, when the grease pressure is too low, the injected grease flows into the bottom of the valve cavity, which usually occurs in a small gate valve. On the one hand, the grease injection pressure is too high. On the one hand, the grease injection nozzle is checked. If the grease hole is blocked, the situation is replaced. On the other hand, the grease is hardened. The cleaning solution is used to repeatedly soften the failed sealing grease and inject a new grease. . In addition, the sealing type and sealing material also affect the grease filling pressure. Different sealing forms have different grease filling pressures. Generally, the hard sealing grease pressure is higher than the soft sealing.

 

â—† When filling the valve, pay attention to the problem that the valve is in the switch position. The ball valve is normally in the open position during maintenance and maintenance. In special cases, the maintenance is turned off. Other valves cannot be discussed in terms of opening. The gate valve must be closed when it is being maintained, ensuring 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, resulting in waste.

 

â—† When the valve is greased, the problem of grease injection is often ignored. The pressure, grease injection amount and switch position are normal during the grease filling operation. However, in order to ensure the grease filling effect of the valve, it is sometimes necessary to open or close the valve to check the lubrication effect and confirm that the valve ball or the surface of the valve is evenly lubricated.

 

â—† When filling grease, pay attention to the problem of valve body discharge and wire plug pressure relief. After the valve pressure test, the gas and moisture in the valve chamber of the sealed chamber are boosted due to the increase of the ambient temperature. When the grease is injected, the drain and pressure should be drained first, so as to facilitate the smooth operation of the grease injection work. After the grease is applied, the air and moisture in the sealed chamber are sufficiently replaced. Timely discharge of the valve cavity pressure also ensures the safety of the valve. After the grease is applied, be sure to tighten the drain and pressure relief plug to prevent accidents.

 

â—† When filling grease, pay attention to the problem of uniform grease. In normal fat injection, the fat-producing hole closest to the grease injection port first comes out of fat, then to the low point, and finally to the high point, and the fat is successively produced. If it is not in accordance with the law or does not produce fat, it proves that there is blockage and timely clearing

 

â—† When filling grease, also observe the problem that the valve diameter is flush with the seal seat. For example, if there is a ball valve, if there is open position, you can adjust the opening limiter to the inside to confirm that the hole is straight and locked. Adjusting the limit can not only pursue the opening or closing of a position, but should be considered as a whole. If the opening position is flush and not closed, the valve will not be closed. In the same way, if the adjustment is in place, the corresponding adjustments should also be considered. Ensure the right angle of the valve

 

â—† After filling the grease, the grease injection port must be sealed. Avoid the entry of impurities, or the oxidation of grease at the grease injection port. Apply anti-rust grease to the cover to avoid rust. For the next application

 

â—† When filling grease, it is also necessary to consider specific issues in the future delivery of oil products. In view of the different qualities of diesel and gasoline, the ability to flush and decompose gasoline should be considered. In the future operation of the valve, when encountering the gasoline section, timely replenish the grease to prevent wear and tear.

 

â—† When filling grease, do not ignore the grease filling on the stem. There is a sliding bushing or packing on the valve shaft, and it is also necessary to maintain the lubrication state to reduce the frictional resistance during operation. If the lubrication cannot be ensured, the torque is increased during the electric operation, and the switch is laborious during manual operation.

 

â—† Some ball valve bodies are marked with arrows. If there is no English FIOW handwriting, it is the direction of action of the sealing seat. It is not used as a reference for medium flow, and the valve is in the opposite direction. Normally, the two-seat sealed ball valve has a two-way flow direction

 

â—† When maintaining the valve, pay attention to the water inlet problem in the motorized head and its transmission mechanism. Especially the rain that infiltrates during the rainy season. One is to rust the transmission mechanism or the transmission bushing, and the other is to freeze in winter. The torque caused by the operation of the electric valve is too large. Damage to the transmission parts may cause the motor to be unloaded or the over-torque protection may not be electrically operated. The drive components are damaged and cannot be performed manually. After the over-torque protection action, manual operation can also not be switched. If forced operation, the internal alloy parts will be damaged.

 

Valve maintenance should be treated with a scientific attitude in order to achieve the desired effect and application of the valve maintenance work. In order to make production work properly, reduce parking, and increase economic efficiency, these three points must be done in terms of valves.

First, the correct choice of valve is the basis

Second, the most critical use of the valve

Third, correct maintenance is a guarantee