Pipeline ball valve maintenance and management techniques 1. Construction period maintenance and management During the construction of the ball valve for scientific management and maintenance, is very important in the construction period of equipment management in place to maintain science, not only to ensure safety, but also can greatly reduce the cost of construction and operation management period . Mainly should pay attention to the following aspects: ①should adopt the correct method to unload the valve, avoids the valve by the mechanical damage. Lifting the valve, the lifting strap can not be tied to the valve stem or actuator for lifting, otherwise it will cause the valve stem bending, valve seal failure and damage to the gear box; ② Factory prior to the installation of easy simple blind at both ends of the valve Plate, to avoid water and sand and other impurities entering the valve cavity during transportation and on the construction site, causing corrosion and damage to the seal. ③ At the construction site, the valves are preferably arranged neatly on the sleepers, and should not be placed anywhere to avoid Sewage nozzle, grease nozzle, etc. are damaged or broken; ④ Before installation, the valve must be injected grease. Through the grease on the one hand check the grease injection channel is smooth, on the other hand to the valve seat sealing surface and the back cavity filled to avoid impurities into the sealing surface and the back cavity, to a certain extent, can reduce the welding temperature on the seat Damage; ⑤ in the installation of the entire process to maintain the valve in full open position; ⑥ when the welding is completed and done hydrostatic test and before and after each operation, to fill in a certain amount of grease in time; , To the valve chamber of water in a timely manner clean to prevent corrosion and icing. 2. Routine maintenance during operation and maintenance recommendations ①periodic inspection of the valve seal, through the sewage nozzle to check, if there is leakage, according to internal leakage treatment procedures for processing; ② timely to the valve seat to inject a certain amount of fresh lubrication Fat, the amount and frequency of injection in accordance with the frequency of valve activity may be, generally when the valve activity once, to appropriate amount of grease, each injection volume is about 1/8 of the volume of the sealing system, the purpose of doing so is the maximum To avoid impurities in the pipe into the seat back cavity, affecting the valve seat movement, resulting in seal failure, while ensuring that the sealing surface at a time in a "wet" state; ③ valve rarely activities, at least 1 times a year, while injecting the right amount Grease, do so to avoid the ball and the seat glued, but also to prevent the ball dry grinding activities, the protection of the seat and the ball; ④ pre-winter ball valve to conduct a comprehensive maintenance and repair, the key to discharge the valve cavity and The water inside the implementing agency to avoid freezing in winter, affecting normal functions; ⑤ replacing the grease in the gear transmission mechanism once a year; ⑥ setting Diameter check valve seal, once leakage occurs, to be in time; ⑦ remove corrosion, external maintenance. Fourth, common faults and troubleshooting 1. Ball valve leakage ball valve leakage is the most common problem of natural gas pipeline valve. (1) Causes of Leakage within the Ball Valve 1) Reasons for Leakage within the Valve during Construction: ①Improper transportation and hoisting cause the valve to be damaged as a whole resulting in leakage of the valve; ② When leaving the factory, the valve is not dried by hydraulic pressure Anti-corrosion treatment, resulting in sealing surface rust formation of internal leakage; ③ construction site protection is not in place, the valve is not installed at both ends of the blind, rain, sand and other impurities into the seat, resulting in leakage; ④ installation, there is no valve seat into the grease , Resulting in impurities into the seat back, or welding caused by burns caused by internal leakage; ⑤ valve is not installed in the full position, causing the ball damage, welding, if the valve is not fully open, welding spatter will cause damage to the ball, When the ball with welding spatter will further cause valve seat damage during switching, resulting in internal leakage; ⑥ welding residue and other construction residues caused by sealing surface scratches; ⑦ factory or installation limit is not accurate cause leakage, if the valve stem Displacement of the drive sleeve or other accessories with the assembly angle, the valve will leak. 2) Causes of valve leakage during operation: ①The most common reason is that operators consider the more expensive maintenance costs of the valve does not maintain or lack of scientific management and maintenance of the valve does not preventive maintenance of the valve, Resulting in equipment failure in advance; ② improper operation or maintenance procedures in accordance with the maintenance of internal leakage; ③ In normal operation, the construction of the remaining surface scratches the sealing surface, resulting in internal leakage; ④ pigging improper sealing surface damage caused by internal leakage; ⑤ long-term maintenance or inaction of the valve, resulting in valve seat and the ball lock, resulting in sealing the valve leakage caused by leakage; ⑥ valve switch is not in place within the leak, any ball valve regardless of open, off, generally tilt 2 ° ~ 3 ° may cause leakage [2]; ⑦ many large-diameter ball valve stem stopper, most of the time, due to corrosion and other reasons in the stem and stem stopper will accumulate rust, dust, paint Such as debris, these debris will cause the valve can not be rotated in place and cause leakage - If the valve is buried, lengthen the stem will produce and fall more Rust and impurities impede the valve ball rotation in place, causing valve leakage, ⑧ general implementing agencies have limited, if long-term cause corrosion, grease hardening or limit bolt loose will limit the inaccurate, resulting in internal leakage; ⑨ electric execution The valve position is set before the body, there is no place in place caused by internal leakage; ⑩ lack of periodic maintenance and repair, resulting in seal fat dry, hardened, dried seal grease accumulation in the elastic seat, hinder seat movement , Resulting in seal failure. (2) Determination of internal leakage Natural gas pipeline is commonly used fixed-axis ball valve, the general method of inspection is: Turn the valve to fully open or fully closed position, through the valve body drain nozzle to check whether there is leakage. If it can be drained, the seal is good. If there is always pressure to discharge, you can think of the valve leaked, then the valve to be treated accordingly. However, it is especially emphasized that for the GRoVE B-5 and B-7A ball valves, the PBV ball valve and the ROBERT CORT ball valve can only be checked in the full position because these ball valves open a passage in the valve body. When the full opening position When used to balance line and valve chamber pressure. But when it's all closed, this does not happen. (3) the process of internal leakage ①first check the valve limit to see whether the limit can be adjusted to solve the valve leakage. ② first inject a certain amount of grease to see if leakage can stop, then the injection speed must be slow, while observing the changes in the gauge needle gauge grease gun to determine the internal leakage of the valve. ③ If you can not stop, there may be early injection of sealing grease hardened or sealing surface damage caused by internal leakage. It is recommended to inject the valve cleaning fluid at this time, to clean the sealing surface of the valve and the valve seat. Generally soaked for at least half an hour, if necessary, you can soak for a few hours or even days, until the cured material completely dissolved before doing the next step. It is best to switch the valve several times during this process. ④ re-injection of grease, intermittent open, close the valve, the impurities out of the seat back cavity and sealing surface. ⑤ check in the full position, if there is still leakage, should be injected into the level of sealant, while opening the valve chamber for venting, which can produce large pressure drop, contribute to the seal, under normal circumstances, by injecting reinforced sealant Internal leakage can be eliminated. ⑥ If you still have internal leakage, it is necessary to repair or replace the valve. 2. Leakage stem Most ball valve stem with the upper and lower two seals, under normal circumstances, without any maintenance, but due to prolonged wear or aging, the valve stem may cause leakage. For the injection of the valve stem, you can inject grease to achieve the purpose of temporary leak. Filling sealant should be slow, it is best to use manual grease gun. When the leak stops, it should stop filling, excessive filling will cause stem rotation difficulties. Of course, some of the stem according to the structure can be sealed by filling the packing or packing gland. 3. Ball 阗 operation abnormalities 1) ball valve maintenance and activities for a long time, the valve seat may be locked with the ball, the operation of the valve more laborious or even fixed, then the best injection of a certain amount of cleaning fluid soak for some time and then Operate. 2) Garbage, sand, dust or aging in the pipeline, hardened sealant accumulates around the seat ring and affects the valve seat movement, causing the seat ring to jam and causing leakage between the seat and the ball. The valve is usually filled with a cleaning solution to remove impurities. 3) When the water content in natural gas is high, condensate water will appear in the transport process as the environment changes. The water in the valve will have the lowest point of the valve, which usually will be the lower pivot or the lower part of the ball valve body, freezing at colder temperatures causing the valve to open and close. 4) When handling the stem leaking, tightening the tightening screw may cause the switch to be too tight. The tightening screw should not be too loose or too tight. 5) For the ball valve operated by worm gear and worm gear drive, the following reasons may also occur: ①serious wear and tear of gear teeth, resulting in inability to properly engage; ② the safety pin on the worm broken; ③ the bearing on the worm or worm gear is damaged; ④ Turbine, worm lubrication is not good, grease used in these areas is usually petroleum-based, will be contaminated with water, in cold weather, the water can freeze, making the valve inoperable. If this happens, disassemble the gearbox to remove any ice, water and contaminated grease and reapply new grease - it is best to use low temperature greases such as ethanol-based greases ; ⑤ bolts and bolts connected to the valve body loose or was cut; ⑥ electric head failure, there is no power supply, wiring or setting errors. 6) For the gas-liquid ball valve may also have the following reasons: ①gas line, the oil line may be blocked or the line speed limit valve is closed; ② insufficient air pressure; ③ hydraulic cylinder or rotary seal failure; ④ pressure Torque caused by other reasons. V. Conclusion To improve the reliability of the valve to extend the service life of the valve, do a good job early, especially during the construction and commissioning of the maintenance and supervision is very important. To this end recommendations: ①strengthen equipment factory supervision and supervision of the transport process; ② strengthen the site equipment installation before the maintenance, maintenance and installation of the supervision process; ③ Before installation, be sure to carry out hydraulic pressure test, as early as possible Identify problems and deal with them as soon as possible; ④ change concepts, carry out preventive maintenance management and formulate periodic maintenance plans and strictly implement them; ⑤ strengthen professional training to improve the quality of professional maintenance personnel, so as to maintain and maintain scientific, standardized and safe; Equipment factory, transportation, installation, testing, maintenance, maintenance of accounts, for the future management of the original records and accumulation of raw materials; ⑦ continuous exploration, the establishment of related, scientific maintenance procedures and testing standards.
Pharmaceutical Intermediates
Shandong YunFengLian Chemical Co.,Ltd , https://www.yfluorine.com