Key points for improving the service life of water control valves

　　Water control valves are key equipment in pipeline systems that control the opening and closing of water flow, regulate flow and pressure. Common types include gate valves, globe valves, ball valves, butterfly valves, etc. The service life of water control valves directly affects the operational reliability and maintenance costs of the entire water supply or drainage system. In practical applications, many valves are not scrapped due to normal wear and tear, but rather premature damage caused by improper selection, non-standard installation, operational errors, or inadequate maintenance. Here are several key points to improve the service life of water control valves.

　　1、 Reasonable selection is the foundation for extending lifespan

　　Improper selection is a common cause of premature valve damage, and the following aspects need to be considered when selecting.

　　The characteristics of the medium are the primary consideration factor. Clean media such as clean water and tap water have lower requirements for valves, which can be met by ordinary cast iron or ductile iron valves. Wear resistant valves, such as rubber lined butterfly valves or hard sealed ball valves, should be selected for media containing particles such as sediment and impurities. Valves with soft sealing surfaces or easily clogged flow channels should be avoided. Stainless steel, copper alloy, or fluorine lined valves must be selected for corrosive media. Ordinary carbon steel or cast iron valves will quickly corrode and puncture in corrosive media.

　　Pressure and temperature are also key parameters for selection. The nominal pressure of the valve should be greater than the working pressure of the pipeline and leave a certain margin. The working temperature must be within the allowable temperature range of the valve. Rubber sealed valves are usually suitable for temperatures below 80 degrees Celsius, PTFE sealed valves are suitable for temperatures between 150 and 200 degrees Celsius, and metal hard sealed valves can withstand higher temperatures. When used beyond the temperature range, the sealing material will quickly age and fail.

　　The selection of valve type is equally important. Ball valves or butterfly valves should be used for situations that require frequent opening and closing, and gate valves or globe valves should not be used. In situations where precise flow regulation is required, globe valves or regulating butterfly valves should be selected. Ball valves or butterfly valves should be selected for situations that require quick shut-off. Valves can be used for pipelines that are in a fully open or fully closed state for a long time. Choosing the wrong type can accelerate valve wear or cause inconvenience in operation.

　　2、 Standardized installation is the guarantee for extending lifespan

　　The installation quality directly determines the service life of the valve. Before installation, the pipeline must be thoroughly purged or flushed to remove hard debris such as welding slag, rust, and mud. Once these impurities enter the interior of the valve, they can scratch the sealing surface, get stuck in moving parts, and cause the valve to not close tightly or operate smoothly. For newly installed pipelines, this step is particularly crucial but often overlooked.

　　Valves should be installed in the correct direction. Most water control valves have clear flow requirements, and arrow markings are usually cast on the valve body. Valves with strong directional characteristics such as globe valves and check valves, when installed upside down, not only fail to function properly but also experience abnormal pressure, accelerating damage. Although gate valves and ball valves are usually sealed in both directions, installing them in the standard flow direction is still more conducive to long-term use.

　　When connecting flanges, bolts should be tightened symmetrically and evenly to prevent deformation of the valve body due to uneven stress. Valve body deformation can cause misalignment of the sealing surface and bending of the valve stem, seriously affecting the service life of the valve. When connecting with threads, a pipe clamp should be used to clamp the hexagonal part on the valve body, and the connection should be made by rotating the pipeline. The pipeline should not be tightened by rotating the valve to avoid twisting the valve body. When welding connections, heat dissipation measures should be taken to prevent high temperature damage to internal seals.

　　The installation location should be convenient for operation and maintenance. The handwheel or handle should have sufficient operating space, and there should be no obstacles around the valve. Valves installed in damp or outdoor environments should be protected against rain and moisture. Valves installed in underground chambers should pay attention to waterproofing and ventilation.

　　3、 Correct operation is the key to extending lifespan

　　Incorrect operating habits are a significant cause of premature valve damage. When opening and closing valves, slow and even force should be applied, and extended levers or impact force should not be used to forcefully open and close them. Excessive torque can damage the valve stem threads, twist the valve stem, or crush the sealing surface. When the valve is already in the fully open or fully closed position, no further force should be applied. Usually, it can be rotated half a turn to eliminate the preload.

　　Valves should not be used for throttling in a semi open and semi closed state for a long time, unless the valve is specifically designed with a regulating function. Gate valves and ball valves may experience long-term wear and tear on their sealing surfaces due to media erosion, quickly losing their sealing ability. In situations where long-term throttling is required, globe valves or regulating valves should be selected.

　　For gate valves, when fully open, the valve stem should be retracted to the limit position to avoid the valve stem being under pressure for a long time. For globe valves, moderate force is sufficient when closing, as pressing the sealing surface too tightly can easily damage it. For butterfly valves, the butterfly plate should be in the fully open position parallel to the flow direction when opened, and completely perpendicular to the flow direction when closed. For ball valves, they only need to be rotated 90 degrees to open and close, and once in place, they will stop without further force.

　　The opening and closing frequency should be controlled within a reasonable range. Non essential and infrequent operation of the valve will cause certain wear on the sealing surface every time it is opened or closed. But for valves that remain stationary for a long time, regular opening and closing operations should be carried out to prevent rust and adhesion between the valve stem and packing.

　　4、 Regular maintenance is a guarantee for extending lifespan

　　Establishing a regular inspection and maintenance system can timely detect and eliminate hidden dangers, and extend the service life of valves. During daily inspections, pay attention to observing the appearance of the valve and checking for leaks, cracks, or rust on the valve body. When there is a slight leakage at the valve stem packing, the packing gland nut can be tightened appropriately, but it should not be too tight to avoid increasing the resistance to valve stem rotation. When the filler is severely aged, it should be replaced in a timely manner.

　　The moving parts require regular lubrication. Lubricating grease should be regularly added to the valve stem threads and bearing parts to ensure flexible operation. For valves that have not been operated for a long time, they should be opened and closed at least once a year to prevent rusting between the valve stem and packing or between the valve disc and seat.

　　The sealing surface condition needs to be checked regularly. For valves that still have obvious leaks after closure, the sealing surface should be disassembled and inspected. Minor wear can be repaired by grinding, and if the wear is severe, the valve disc or the entire valve should be replaced. After 5 to 8 years of use, even if the condition of the rubber seal ring is still acceptable, it is recommended to replace it preventively, as the sealing performance will sharply decrease after the rubber ages and hardens.

　　The impurities inside the valve body need to be cleaned regularly. In sewage or media with high impurities, impurities are prone to deposit inside the valve, affecting sealing and opening/closing. Combined with the pipeline maintenance cycle, the valve can be disassembled to clean the internal sediment.

　　Fasteners require regular inspection. Flange bolts and gland bolts may become loose due to vibration during operation and should be checked regularly and re tightened. For pipelines that have been exposed to heat or cold for a long time, the thermal expansion and contraction of bolts are more pronounced, and the inspection frequency should be appropriately increased.

　　5、 Operating environment management is an auxiliary measure to extend lifespan

　　The operating environment also has a significant impact on the lifespan of valves. Valves installed outdoors should be equipped with protective covers to prevent rainwater, direct sunlight, and extreme temperature changes. Valves installed in damp environments or underground should be treated with anti-corrosion measures, such as painting with anti-corrosion paint or wrapping with anti-corrosion tape. In cold regions, outdoor valves should be insulated to prevent water accumulation, freezing, and expansion inside the valve body, which can lead to valve cracking.

　　The water hammer control of pipeline systems is crucial for valve protection. Severe pressure fluctuations can impact the valve disc and sealing surface, causing damage. Slow closing check valves, water hammer eliminators, or pressure relief valves can be installed in the system to reduce the impact of water hammer. When starting or stopping the water pump, it should be operated slowly to avoid sudden opening or closing.

　　Medium purification is also an effective means to extend the service life of valves. Installing a filter upstream of the valve can intercept impurities and protect the valve sealing surface. For media with strong wear resistance, the accuracy of the filter should be appropriately improved. Regularly clean the filter to avoid clogging and affecting system operation.

　　6、 Common errors and improvement measures

　　In practical use, the following errors will significantly shorten the lifespan of the valve. One is to use gate valves or ball valves for flow regulation, which may cause damage to the sealing surface due to long-term erosion by the medium. The improvement measure is to replace it with globe valves or regulating valves. The second issue is that excessive force may cause damage to the sealing surface or valve stem when closing the valve. The improvement measure is to use a standard length wrench and stop when it is in place. The third issue is the rusting of valves that have not been operated for a long time. The improvement measure is to operate them at least once a year. The fourth issue is that the pipeline was not cleaned before installation, and impurities scratched the sealing surface. The improvement measure is to strictly blow it before installation. The fifth is the use beyond the temperature or pressure range, which leads to the failure of the sealing material. The improvement measures are to reselect or improve the working conditions.

　　summary

　　The key points to improve the service life of water control valves can be summarized as follows: reasonable selection is the foundation, standardized installation is the guarantee, correct operation is the key, regular maintenance is the guarantee, and environmental management is the auxiliary. Starting from the selection of valves, to every step of installation, operation, and maintenance, the service life of water control valves can be significantly extended. Taking ordinary gate valves as an example, valves with appropriate selection, standardized installation, correct operation, and proper maintenance can have a service life of 15 to 20 years, while valves with poor management may experience serious leakage or jamming within three to five years. Exchanging a longer service life of valves with smaller management investment not only reduces equipment replacement costs, but also minimizes losses caused by water and production shutdowns due to valve failures. This is an important equipment management task that deserves attention.