Details of the structure and installation of the electric valve The operating distance of the electric valve is larger than that of an ordinary valve. The switching speed of the electric valve can be adjusted, the structure is simple, and it is easy to maintain. Because of the buffering properties of the gas during operation, it is not easy to damage due to jamming. There must be an air supply, and its control system is also more complicated than the electric valve. This type of valve should generally be installed horizontally in the pipeline.
Electric valves are usually composed of electric actuators and valves. The electric valve uses electric energy as power to drive the valve through the electric actuator to realize the valve switching action. In order to achieve the purpose of switching the pipeline medium. So, what are the details of the electric valve during installation?
The electric valve device is an indispensable device for implementing valve control, automatic control and remote control. The movement process can be controlled by the size of stroke, torque or axial thrust. Since the operating characteristics and utilization of the 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 the electric valve device will prevent the occurrence of an overload phenomenon (the working torque is higher than the control Torque is very important. In general, the correct selection of electric valve devices is based on the following:
Operating Torque Operating torque is the most important parameter for selecting the electric valve device. The output torque of the electric device should be 1.2 to 1.5 times the maximum torque of the valve.
There are two types of mainframes for operating the thrust electric valve device: one is to directly output the torque without the thrust plate; the other is to configure the thrust plate, and the output torque is converted into the output thrust through the stem nut in the thrust plate.
Output shaft rotation number The number of rotations of the output shaft of the electric valve device is related to the nominal diameter of the valve, the pitch of the valve stem, and the number of threads. It is calculated according to M=H/ZS (M is the total rotation that the electric device should meet. Number, H is the valve opening height, S is the valve stem transmission thread pitch, Z is the valve stem thread head number).
Stem Diameter For multi-rotary type stem valves, if the maximum valve stem diameter allowed by the electric device cannot pass through the valve stem of the valve with which it is fitted, it cannot be assembled into an electric valve. Therefore, the inner diameter of the hollow output shaft of the electric device must be greater than the outer diameter of the stem of the stem valve. For the rotary valve and the multi-rotary valve, although the stem diameter does not have to be taken into account, the diameter of the stem and the size of the key groove should be fully taken into account during the selection, so that the assembly can work normally.
If the speed of opening and closing of the output speed valve is too fast, water hammer may easily occur. Therefore, the appropriate opening and closing speed should be selected according to different conditions of use.
The electric valve device has its special requirement that it must be able to limit the torque or axial force. Usually the electric valve device uses a torque limiting coupling. When the specifications of the electric device are determined, the control torque is determined. Generally run within a predetermined time, the motor will not be overloaded. However, the following conditions may lead to overload: First, the power supply voltage is low, the required torque is not available, so that the motor stops rotating; second, the torque limiting mechanism is incorrectly set to be greater than the stopping torque, Caused by continuous generation of excessive torque, so that the motor stops rotating; Third, intermittent use, the resulting heat accumulation, exceeding the allowable temperature rise of the motor; Fourth, for some reason the torque limit mechanism circuit failure, so that torque Large; fifth is the use of high ambient temperature, relative to the thermal capacity of the motor.
The way to protect the motor in the past was to use fuses, overcurrent relays, thermal relays, thermostats, etc., but these methods have their own advantages and disadvantages. For electric devices such as variable load equipment, absolutely reliable protection methods are not available. Therefore, we must take various combinations, summed up in two ways: one is to judge the increase or decrease of the motor input current; the second is to judge the heat of the motor itself. Both of these methods, regardless of the kind, must take into consideration the time margin given by the thermal capacity of the motor.
In general, the basic methods of overload protection are: overload protection for continuous operation or jog operation of the motor using a thermostat; thermal relays for motor stall protection; fuses or overcurrent relays for short circuit accidents.
Electric valves are usually composed of electric actuators and valves. The electric valve uses electric energy as power to drive the valve through the electric actuator to realize the valve switching action. In order to achieve the purpose of switching the pipeline medium. So, what are the details of the electric valve during installation?
The electric valve device is an indispensable device for implementing valve control, automatic control and remote control. The movement process can be controlled by the size of stroke, torque or axial thrust. Since the operating characteristics and utilization of the 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 the electric valve device will prevent the occurrence of an overload phenomenon (the working torque is higher than the control Torque is very important. In general, the correct selection of electric valve devices is based on the following:
Operating Torque Operating torque is the most important parameter for selecting the electric valve device. The output torque of the electric device should be 1.2 to 1.5 times the maximum torque of the valve.
There are two types of mainframes for operating the thrust electric valve device: one is to directly output the torque without the thrust plate; the other is to configure the thrust plate, and the output torque is converted into the output thrust through the stem nut in the thrust plate.
Output shaft rotation number The number of rotations of the output shaft of the electric valve device is related to the nominal diameter of the valve, the pitch of the valve stem, and the number of threads. It is calculated according to M=H/ZS (M is the total rotation that the electric device should meet. Number, H is the valve opening height, S is the valve stem transmission thread pitch, Z is the valve stem thread head number).
Stem Diameter For multi-rotary type stem valves, if the maximum valve stem diameter allowed by the electric device cannot pass through the valve stem of the valve with which it is fitted, it cannot be assembled into an electric valve. Therefore, the inner diameter of the hollow output shaft of the electric device must be greater than the outer diameter of the stem of the stem valve. For the rotary valve and the multi-rotary valve, although the stem diameter does not have to be taken into account, the diameter of the stem and the size of the key groove should be fully taken into account during the selection, so that the assembly can work normally.
If the speed of opening and closing of the output speed valve is too fast, water hammer may easily occur. Therefore, the appropriate opening and closing speed should be selected according to different conditions of use.
The electric valve device has its special requirement that it must be able to limit the torque or axial force. Usually the electric valve device uses a torque limiting coupling. When the specifications of the electric device are determined, the control torque is determined. Generally run within a predetermined time, the motor will not be overloaded. However, the following conditions may lead to overload: First, the power supply voltage is low, the required torque is not available, so that the motor stops rotating; second, the torque limiting mechanism is incorrectly set to be greater than the stopping torque, Caused by continuous generation of excessive torque, so that the motor stops rotating; Third, intermittent use, the resulting heat accumulation, exceeding the allowable temperature rise of the motor; Fourth, for some reason the torque limit mechanism circuit failure, so that torque Large; fifth is the use of high ambient temperature, relative to the thermal capacity of the motor.
The way to protect the motor in the past was to use fuses, overcurrent relays, thermal relays, thermostats, etc., but these methods have their own advantages and disadvantages. For electric devices such as variable load equipment, absolutely reliable protection methods are not available. Therefore, we must take various combinations, summed up in two ways: one is to judge the increase or decrease of the motor input current; the second is to judge the heat of the motor itself. Both of these methods, regardless of the kind, must take into consideration the time margin given by the thermal capacity of the motor.
In general, the basic methods of overload protection are: overload protection for continuous operation or jog operation of the motor using a thermostat; thermal relays for motor stall protection; fuses or overcurrent relays for short circuit accidents.
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