The action force distance of electric valve is larger than that of ordinary valve. The action speed of electric valve can be adjusted. The structure is simple and easy to maintain. In the process of action, due to the buffer characteristics of gas itself, it is not easy to be stuck and damaged, but there must be a gas source, and its control system is more complex than that of electric valve. This kind of valve should be installed horizontally in the pipeline.

Electric valve is usually composed of electric actuator and valve. The electric valve uses the electric energy as the power to drive the valve through the electric actuator to realize the opening and closing action of the valve. So as to achieve the purpose of switching the pipeline medium. So, what are the details to be paid attention to during the installation of the electric valve?

The electric valve device is an indispensable equipment to realize the program control, automatic control and remote control of the valve. Its movement process can be controlled by the stroke, torque or axial thrust. Because the working characteristics and utilization rate of electric valve device depend on the type of valve, the working specification of the device and the position of the valve on the pipeline or equipment, the correct selection of electric valve device is very important to prevent overload (working torque is higher than control torque). Generally, the basis for the correct selection of electric valve device is as follows:

Operating torque operating torque is the most important parameter for selecting electric valve device. The output torque of electric device shall be 1.2-1.5 times of the maximum operating torque of valve.

There are two main structures for operating the thrust electric butterfly valve device: one is to directly output the torque without the thrust disk; the other is to configure the thrust disk, and the output torque is converted into the output thrust through the stem nut of the thrust disk.

The number of turns of the output shaft of the electric valve device is related to the nominal diameter of the valve, the screw pitch of the valve rod and the number of screw heads. It should be calculated according to M = H / ZS (M is the total number of turns that the electric device should meet, H is the opening height of the valve, s is the screw pitch of the valve rod drive, and Z is the number of screw heads of the valve rod).

If the maximum diameter of the valve stem allowed by the electric device cannot pass through the valve stem of the matched valve, it cannot be assembled into an electric valve. Therefore, the inner diameter of the hollow output shaft of the electric device must be larger than the outer diameter of the stem of the rising stem valve. Although it is not necessary to consider the passing of stem diameter for some rotary valves and concealed stem valves in multi rotary valves, it is also necessary to fully consider the stem diameter and the size of keyway when selecting and matching, so that they can work normally after assembly.

If the opening and closing speed of the output speed valve is too fast, water hammer is easy to occur. Therefore, the proper opening and closing speed should be selected according to different conditions.

Electric valve device has its special requirements, that is, it must be able to limit torque or axial force. In general, electric valve device adopts coupling with limited torque. When the specification of the electric device is determined, its control torque is also determined. Generally, the motor will not be overloaded when it runs in a predetermined time. However, overload may be caused by the following conditions: first, the power supply voltage is low, and the required torque cannot be obtained, so that the motor stops rotating; second, the torque limiting mechanism is adjusted incorrectly, so that it is larger than the stop torque, resulting in continuous excessive torque, so that the motor stops rotating; third, intermittent use, resulting in heat accumulation, which exceeds the allowable temperature appreciation of the motor; fourth, due to a certain The fifth reason is that the temperature of the operating environment is too high, which makes the thermal capacity of the motor decrease.

In the past, fuse, over-current relay, thermal relay and thermostat were used to protect the motor, but these methods have their own advantages and disadvantages. There is no absolutely reliable protection method for the load changing equipment of electric device. Therefore, it is necessary to adopt various combinations, which can be summed up in two ways: one is to judge the increase or decrease of the input current of the motor; the other is to judge the heating condition of the motor itself. In either case, the time margin given by the thermal capacity of the motor shall be considered.