How to Prolong the Service Life of Ball Valves?
Apr 21, 2022
Ball valves are widely used in China, and it is indispensable in the chemical industry, water conservancy, electric power, steel, petroleum refining and other industries. In the pipeline of the ball valve, it is mainly used to cut off, distribute and change the flow direction of the medium. It can be closed tightly only by rotating 90° and small torque. There are many kinds of ball valves. For example, electric ball valves should pay special attention to the environmental conditions besides the pipeline parameters. Because the electric device in the electric valve is an electromechanical device, its use status is greatly affected by its use environment. Then, how to prolong the service life of the ball valve, which is applied in daily life or in various industries?
To prolong the service life of ball valves, it is very useful to know some common sense or knowledge about valves. If you want a ball valve to have a long service life, you must rely on the following factors:
1. Normal working conditions
2. Maintaining a harmonious temperature/pressure ratio
3. When the ball valve is closed, there is still pressurized fluid inside the valve body.
With regard to disassembly, it is necessary to check the upstream and downstream pipelines of the ball valve to make sure that the pressure has been removed before disassembly and disassembly; When assembling again after disassembly, remember to be careful to prevent damage to the sealing surface of parts, especially non-metallic parts. Use special tools to operate, and the bolts of flanges should be tightened symmetrically and evenly.
Regarding cleaning, the cleaning agent should be compatible with the rubber parts, plastic parts, metal parts and working media in the ball valve. For example, when the working medium is gas, the metal parts can be cleaned with gasoline, and the nonmetal parts can be cleaned with pure water or alcohol. When cleaning nonmetal parts, be careful not to soak them for a long time. After the components are cleaned, the components can be assembled after the detergent is volatilized or wiped off. But it can't be put on hold for a long time, otherwise, it will rust and be polluted by dust, so it will be washed in vain. During assembly, dust such as metal chips, fibers, grease or other impurities is not allowed to adhere to the surface of parts or enter the cavity. Also, if there is leakage at the packing, the valve stem nut should be locked again.
Use grease, which should also be compatible with working media such as metal materials, rubber parts and plastic parts of ball valves. When the working medium is gas, special grease can be used. Apply a thin layer of grease on the surface of the seal installation groove, the rubber seal and the sealing surface of the valve stem.
Ball valves are versatile, with advantages and disadvantages:
Advantages:
1. It won't get stuck when working, even in the lubricant-free type. It can be reliably applied to corrosive medium and low boiling point liquid;
2. Complete sealing can be achieved in a large pressure and temperature range;
3. It can realize quick opening and closing, compact structure and lightweight, which can be considered the most reasonable valve structure for the low-temperature medium system;
4. Especially the welded valve body structure can well bear the stress from the pipeline;
5. The ball valve with an all-welded valve body can be directly buried in the ground, so that its internals will not be eroded, and its maximum service life can reach 30 years. It is the most ideal valve for oil and natural gas pipelines.
Disadvantages:
1. The sealing ring of the valve seat of the ball valve is made of polytetrafluoroethylene, which has the comprehensive characteristics of small friction coefficient, stable performance, difficult aging, wide temperature application range and excellent sealing performance. However, it has low-temperature resistance, so it can only be used under the condition of less than 180℃. If this temperature exceeds, the sealing material will age and the reliability of the seal will be destroyed. Therefore, for long-term use, it is usually only used at 120℃.
2. Its regulating performance is worse than that of globe valves, especially pneumatic valves or electric valves.
To prolong the service life of ball valves, it is very useful to know some common sense or knowledge about valves. If you want a ball valve to have a long service life, you must rely on the following factors:
1. Normal working conditions
2. Maintaining a harmonious temperature/pressure ratio
3. When the ball valve is closed, there is still pressurized fluid inside the valve body.
With regard to disassembly, it is necessary to check the upstream and downstream pipelines of the ball valve to make sure that the pressure has been removed before disassembly and disassembly; When assembling again after disassembly, remember to be careful to prevent damage to the sealing surface of parts, especially non-metallic parts. Use special tools to operate, and the bolts of flanges should be tightened symmetrically and evenly.
Regarding cleaning, the cleaning agent should be compatible with the rubber parts, plastic parts, metal parts and working media in the ball valve. For example, when the working medium is gas, the metal parts can be cleaned with gasoline, and the nonmetal parts can be cleaned with pure water or alcohol. When cleaning nonmetal parts, be careful not to soak them for a long time. After the components are cleaned, the components can be assembled after the detergent is volatilized or wiped off. But it can't be put on hold for a long time, otherwise, it will rust and be polluted by dust, so it will be washed in vain. During assembly, dust such as metal chips, fibers, grease or other impurities is not allowed to adhere to the surface of parts or enter the cavity. Also, if there is leakage at the packing, the valve stem nut should be locked again.
Use grease, which should also be compatible with working media such as metal materials, rubber parts and plastic parts of ball valves. When the working medium is gas, special grease can be used. Apply a thin layer of grease on the surface of the seal installation groove, the rubber seal and the sealing surface of the valve stem.
Ball valves are versatile, with advantages and disadvantages:
Advantages:
1. It won't get stuck when working, even in the lubricant-free type. It can be reliably applied to corrosive medium and low boiling point liquid;
2. Complete sealing can be achieved in a large pressure and temperature range;
3. It can realize quick opening and closing, compact structure and lightweight, which can be considered the most reasonable valve structure for the low-temperature medium system;
4. Especially the welded valve body structure can well bear the stress from the pipeline;
5. The ball valve with an all-welded valve body can be directly buried in the ground, so that its internals will not be eroded, and its maximum service life can reach 30 years. It is the most ideal valve for oil and natural gas pipelines.
Disadvantages:
1. The sealing ring of the valve seat of the ball valve is made of polytetrafluoroethylene, which has the comprehensive characteristics of small friction coefficient, stable performance, difficult aging, wide temperature application range and excellent sealing performance. However, it has low-temperature resistance, so it can only be used under the condition of less than 180℃. If this temperature exceeds, the sealing material will age and the reliability of the seal will be destroyed. Therefore, for long-term use, it is usually only used at 120℃.
2. Its regulating performance is worse than that of globe valves, especially pneumatic valves or electric valves.
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