Sep.20.2024
The passage provides a detailed overview of troubleshooting methods for electric butterfly valves, specifically focusing on the electric valve actuators. The electric valve actuator is described as consisting of an electronic control part and a power part, with common faults categorized into control part faults and power part faults. The passage serves as a guide for troubleshooting common problems associated with the power part of electric butterfly valves.
The electric valve limit switch box is an on-site instrument that detects the status of the valve in the automatic control system. It is used to output the open or closed position of the valve as a switching signal, which is received by the program controller or sampled by the computer. After confirmation, the next step is executed. Electric valves can also be used as important valve chain protection and remote alarm instructions in automatic control systems.
Common faults of electric butterfly valves:
Electric butterfly valve troubleshooting method:
By electric butterfly valves, which are included in this category, the valve body has a gate that passes through the structure and intersects a cavity of a traditional valve, with the cavity opening and closing between positions, and an actuator responsible for moving these positions between the gates.
As is also the case with this type of valve, the actuator consists of a hood mounted on the valve body with a stem connected to the additional valve.
Electric valve actuators are generally composed of an electronic control part and a power part. Therefore, common faults in electric valve actuators can be divided into control part faults and power part faults.
Below we introduce in detail the common faults of the power part and their cause analysis and troubleshooting measures.
The power of electric valve actuators is generally provided by motors, so it is necessary to master some knowledge about motors.
In this way, we can discover and eliminate potential accident hazards of the electric motor on the electric actuator as soon as possible and ensure the safe operation of the electric actuator and electric valve.
Mechanical failure:
1. Motor sweep:
The gap between the stator and rotor of the motor is very small, which can easily cause the stator and rotor to collide. Once the base, end cover, and rotor have different axes, it will cause the stator and rotor to collide, which is often called chamber sweeping.
Common factors causing different axis phenomena are:
The motor bearing is seriously out of tolerance, the inner hole of the end cover is worn, and the stop hole of the end cover and the base stop hole are worn and deformed. If these phenomena are found, the bearing should be replaced, or the end cover should be replaced or brush-plated.
2. Motor vibration:
Vibration should first be distinguished whether it is caused by the motor itself, caused by a defective transmission device, or transmitted from the mechanical load end, and then eliminated according to the specific situation.
Vibrations caused by the motor itself are mostly caused by poor dynamic balance of the rotor, poor bearings, bent shafts, or different axes of the end cover, base, and rotor; or the motor installation foundation is uneven, the installation is not in place, and the fasteners are loose. of. Vibration creates noise and creates additional loads.
3. The bearing is not working properly:
If the bearing is not working properly, it can be judged based on experience using hearing and temperature. Use a listening rod (copper rod) to touch the bearing box. If you hear an impact sound, it means that one or several balls may be broken. If you hear a hissing sound, it means that the bearing has insufficient lubricating oil. It is not easy to add too much grease. If it is too much, there will be great friction between the rotating part of the bearing and the grease and heat. Generally, the grease in the bearing box is about one-half to one-third of the total dissolved volume. The second is enough. If the bearing is installed incorrectly and the fitting tolerance is too tight or too loose, it will also cause the bearing to heat up.
The electric butterfly valve has a simple structure, consisting of only a few parts, and consumes less material; it is small in size, light in weight, small in installation size, small in driving torque, and is a pressure regulating valve. It is easy and quick to operate and can be quickly started by just rotating 90°. closed; and it also has good flow regulation function and closed sealing characteristics. In the application fields of large and medium diameter, medium and low pressure, electric ball valve is the leading valve. When the electric butterfly valve is in the fully open position, the thickness of the butterfly plate is the resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. Electric butterfly valves have two sealing types: elastic seal and metal seal. For elastic sealing valves, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate. Valves with metal seals generally have a longer service life than valves with elastic seals, but it is difficult to achieve complete sealing. Metal seals can adapt to high.
If an electric butterfly valve is required to be used for flow control, it is important to select the size and type of valve correctly. The structural principle of electric ball valve is especially suitable for manufacturing large diameter valves.
Electric butterfly valves are not only widely used in general industries such as petroleum, gas, chemical industry, and water treatment, but are also used in the cooling water system of thermal power stations.
Commonly used electric butterfly valves include wafer-type electric butterfly valves and flange-type electric butterfly valves. The wafer-type electric butterfly valve uses studs to connect the valve between two pipe flanges. The flange-type electric butterfly valve has a flange on the valve, and bolts are used to connect the flanges at both ends of the valve to the pipe flange.
The strength performance of the valve refers to the valve's ability to withstand medium pressure. Valves are mechanical products that are subject to internal pressure, so they must have sufficient strength and rigidity to ensure long-term use without cracking or deformation.
The electric butterfly valve has a simple structure, consisting of only a few parts, and consumes less material; it is small in size, light in weight, small in installation size, small in driving torque, and is a pressure regulating valve. It is easy and quick to operate and can be quickly started by just rotating 90°. closed; and it also has good flow regulation function and closed sealing characteristics. In the application fields of large and medium diameter, medium and low pressure, electric ball valve is the leading valve. When the electric butterfly valve is in the fully open position, the thickness of the butterfly plate is the resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. Electric butterfly valves have two sealing types: elastic seal and metal seal. For elastic sealing valves, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate. Valves with metal seals generally have a longer service life than valves with elastic seals, but it is difficult to achieve complete sealing. Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being temperature limited.
