Application Principle of Electric Ball Valve and Troubleshooting of Various Faults
Troubleshooting Electric valve actuators are generally composed of two parts: 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 next power part and their cause analysis and troubleshooting measures. The power of the electric valve actuator is generally provided by the motor, so it is necessary to master some knowledge of the motor. In this way, we can discover and eliminate the hidden dangers of electric motors on electric actuators as soon as possible, and ensure the safe operation of electric actuators and electric valves.
Mechanical failure
1. Motor bore: The gap between the stator and rotor of the motor is very small, which is easy to cause collision between the stator and rotor. Once there is a phenomenon that the base, the end cover, and the rotor have different axis, it will cause the collision between the stator and the rotor, which is often referred to as sweeping. The common factors that cause 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 stop hole of the machine base are worn and deformed. If these phenomena are found, the bearing should be replaced, or the end cover should be replaced or brushed.
2. Motor vibration: Vibration should be distinguished whether it is caused by the motor itself, caused by a defective transmission device, or transmitted by the mechanical load end, and then eliminated according to the specific situation. It belongs to the vibration caused by the motor itself, mostly due to poor rotor dynamic balance, poor bearing, bending of the shaft, or different axis of the end cover, frame, and rotor, or the motor installation foundation is uneven, the installation is not in place, and the fasteners are loose. Vibration generates noise and also generates additional load.
3. The bearing is not working properly: If the bearing is not working properly, it can be judged by hearing and temperature based on experience. 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 sizzling sound, it means that the bearing is not lubricated. It is not easy to add too much grease. If too much, it will cause a lot of friction between the rotating part of the bearing and the grease and generate heat. Generally, the grease placed in the bearing box is about one-half to three-thirds of the total dissolved volume. The second is OK. If the bearing is installed incorrectly, the fit tolerance is too tight or too loose, it will also cause the bearing to heat up.
Common failures of electric ball valves are typical failures, safety valves, springs between the valve stems and a drive installed in the actuation of the gate valve reciprocating urges the position of one of the gates, which may be a closed body, the control fluid is applied to the piston in the dry when the actuator overcomes the spring force and maintains it in other positions, it is usually open, so as a long-term maintenance under the control condition, when this structure valve is abandoned at a large depth, and the body pressure is much lower than the surrounding sea pressure drop, the electric ball valve spring must if it is large enough, the force to close the valve due to body pressure is not enough to move the door to its failure position. It can happen in extreme cases. Thereby reducing the size of the actuator and increasing the depth rating of the valve.
The failure of electric ball valve, including the traditional valve in this category, the valve body has a door crossing the structure and a cavity, the cavity between the positions opens and closes, and the actuator is responsible for moving these positions between the doors. As also in the case of this type of valve, the actuator includes an engine cover mounted on the valve body and the valve stem is connected to another valve.
The principle of electric ball valve
The electric ball valve is a combination of a plug-type ball valve and an electric actuator. The structure of the ball valve body is a spool that rotates 90 degrees. The electric actuator inputs a standard signal of 0-10 mA. The motor group drives the gear and worm gear angle torque. Adjust the valve with the switch box. Its use is mainly produced by the amount of current and adjustment operations.
Repair method
1. The ball valve can be disassembled only after the pressure before and after the ball valve is removed.
2. In the process of disassembling and reassembling the ball valve, it is necessary to protect the sealing parts, especially non-metal parts, such as O-rings and other parts, it is best to use special tools.
3. The bolts must be tightened symmetrically, gradually and evenly when reassembling the ball valve body.
4. The cleaning agent should be compatible with the rubber parts, plastic parts, metal parts and working medium (such as gas) in the ball valve. When the working medium is gas, gasoline (GB484-89) can be used to clean metal parts. Clean non-metal parts with pure water or alcohol.
5. The individual parts that are decomposed can be cleaned by dipping. Metal parts with undecomposed non-metal parts can be scrubbed with clean, fine silk cloth impregnated with cleaning agent (to avoid fiber falling off and adhering to the parts). When cleaning, remove all grease, dirt, glue, dust, etc. adhering to the wall.
6. Non-metal parts should be taken out of the cleaning agent immediately after cleaning, and they should not be soaked for a long time.
7. After cleaning, it needs to be assembled after the cleaning agent of the wall surface to be washed evaporates (can be wiped with silk cloth not soaked in cleaning agent), but it should not be left for a long time, otherwise it will rust and be contaminated by dust.
8. New parts also need to be cleaned before assembly.
9. Metal chips, fibers, grease (except those specified for use), dust, other impurities, foreign objects, etc., should not be allowed to contaminate, adhere or stay on the surface of the parts or enter the cavity during assembly.
Electric ball valve application
Electric ball valve accounts are now widely used in petroleum, natural gas, medicine, food, hydropower, nuclear power, electricity, water supply and drainage, heating, metallurgy and other industries. They are critical mechanical products for national defense construction. It is also an indispensable product for technological construction. It occupies a lot of the market share, mainly because of many reasons such as strong function, small size, reliable performance, large circulation capacity, light and cheap people, and remote control of the electric ball valve. The electric ball valve is not only throttling, stopping, cutting. Good products for on-off and diversion are also the first choice for fierce products in flow regulation systems. It has many characteristics such as pressure resistance, temperature resistance, corrosion resistance, low flow resistance, long service life and wide application range.
