Process Description of Dissolved Air Flotation
May 15,2023Read More
Valves play an irreplaceable role in production activities. Therefore, valves are important components and play a very critical role. The operation of valves will directly affect the stable production of equipment. Analyzing some common faults in valve operation and improving them through corresponding means and methods can greatly improve the utilization rate of valves and significantly reduce the failure rate. The use of water conservancy valves in the control process can greatly improve production efficiency and economic benefits, and can well control and save energy consumption.
The "water hammer effect" refers to the impact of water flow caused by the inertia of pressure water flow when an open valve suddenly closes, causing destructive effects. This is the water hammer effect in hydraulics, which is also called positive water hammer. Conversely, when a closed valve is suddenly opened, it will also produce a water hammer, called negative water hammer, which also has a certain destructive power, but not as great as the former. Usually, when the valve is close to closing, the closing element suddenly sucks into the seat, which is called the solenoid locking effect. This effect is caused by a low thrust execution mechanism that does not have enough thrust to maintain the position close to the valve seat, resulting in the sudden closing of the pump or valve, thereby producing a water hammer effect. For control valves, in some cases, the fast-opening type flow characteristic valve can also cause water hammer effect.
Backflow is another major problem that can cause extensive damage to pipelines. This is caused by the sudden change in the direction of the flowing liquid. When the direction of water flow in the pipeline is opposite to the direction designed by the system designer, it is called backflow. Technically, this flow reversal is mainly caused by the adverse pressure gradient exerted by external potential flow on the boundary layer. Backflow can cause backflow in the clean water system through siphon action.
Industrial check valves can also be used on pipelines that provide supply to auxiliary systems whose pressure may rise above the system pressure. Check valves can be mainly divided into rotary check valves (rotating according to the center of gravity) and lifting check valves (moving along the axis). The function of this type of valve is to allow the medium to flow in one direction only, and to prevent reverse flow. Usually, this type of valve works automatically. Under the pressure of fluid flowing in one direction, the valve flap opens; when the fluid flows in the opposite direction, the valve flap acts on the valve seat due to the pressure of the fluid and the weight of the valve flap, thereby cutting off the flow.
Valve leakage is a problem we need to face, and we also have good solutions for this problem. We have different measures for leaks in different parts.
Leakage caused by the detachment of the closing member
The closing member being stuck, the connection being damaged, the connection being not tight or the improper selection of connection material can all cause the detachment of the closing member and lead to leakage. Solution: Operate correctly, open the dead point on the valve, regularly check whether the connection between the closing member and the valve stem is firm, and replace the closing member and the valve stem in time if they are corroded by the medium.
Leakage at the connection of the sealing ring
The sealing ring is not compacted, the welding quality is low when the sealing ring is welded with the body, the thread or the screw is loose or corroded can all cause leakage at the connection of the sealing ring. Solution: Use glue to fix the sealing ring compression place, repair and re-weld the poor welding place in time, and replace the corroded or damaged threads and screws in time.
Valve body and valve cover leakage
Low-quality iron-cast parts or poor welding can cause the valve body to freeze-crack when the temperature is too low, the valve to be pressed or hit by external forces, etc., which may cause the valve body to leak. Solution: Choose high-quality cast valves, strictly weld, be prepared for cold weather when the temperature is low, and prevent collisions and heavy pressure.
Valves play an important role in various industries. Once the valve fails, it will cause considerable economic losses and other losses in production activities. Even if the valve fails, valve monitoring can also effectively avoid valve problems to a certain extent. The problem can also be resolved in a timely and effective manner. Therefore, valve monitoring is required during production processes. However, valve failure monitoring must also be effective at the same time. In order to monitor valve failures on-site, we must take effective troubleshooting measures to prevent real-time failures.
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