The structure of the electric pneumatic valve and installation details

electropneumatic valve actuation moment than ordinary pneumatic valves, electric pneumatic valve switching speed can be adjusted, simple structure, easy maintenance, in the process of action for buffer characteristics of the gas itself, is not easy to damage due to get stuck, but must have a gas source, and its control system is more complicated than the electric pneumatic valve. This kind of pneumatic valves shall generally be installed in the pipeline.
electropneumatic valve usually consists of electric actuators, and pneumatic valves. Electric pneumatic valve using electricity as power to drive by electric actuator pneumatic valve, pneumatic valve switch action. To achieve medium switch of the pipes. So, electric pneumatic valve during the installation process should pay attention to what details?
electropneumatic valve device is the realization of program-controlled pneumatic valve, automatic control and remote control of the indispensable equipment, its movement process can by travel, torque, or to control the size of the axial thrust. Because electric pneumatic valve device utilization and depends on the operating characteristics of pneumatic valve type, working rules and pneumatic valve in the pipeline or equipment, therefore, the correct selection of electropneumatic valve device, to prevent overload phenomenon, Work torque is higher than the control torque) Is of crucial importance. Usually, the basis of correct selection of electropneumatic valve device is as follows:
operating torque operating torque is to choose the electric pneumatic valve device is one of the main parameters, pneumatic valve electric actuator output torque should be maximum torque operation. ~。 Times.
host operating thrust electropneumatic valve device structure has two kinds: one kind is not configured thrust plate, direct output torque; The other is a configuration thrust plate, the output torque by thrust plate pneumatic stem nut into output thrust.
output shaft rotation laps electropneumatic valve gear output shaft rotation laps with nominal diameter on the pneumatic valve, pneumatic valve stem thread pitch, thread, according to M = H/ZS computing ( M for electric devices should satisfy the total number of rotating ring, H is height of pneumatic valve opens, S for pneumatic valve stem drive screw pitch, Z for pneumatic valve stem thread) 。
pneumatic valve stem diameter for multi-turn type pneumatic valve stem, if electric device allows the largest pneumatic valve stem diameter can't through the pneumatic valve pneumatic valve stem, cannot assemble into electric pneumatic valve. As a result, the inner diameter of the hollow output shaft electric actuator pneumatic valve pneumatic valve lever must be greater than stem diameter. For part of rotary pneumatic valve and multi-turn non-rising stem of the pneumatic valve pneumatic valve, pneumatic valve stem diameter is not considered through the problem, but also should fully consider when selecting pneumatic valve stem diameter and the size of the keyway, after assembly to work properly.
if output rotation speed of pneumatic valve opening and closing speed too fast, easy to produce water hammer. Therefore, should be used according to different conditions, choosing the proper opening and closing speed.
electropneumatic valve device has its own special requirements, which must be able to limit torque and axial force. Electric pneumatic valve device adopts usually limiting torque shafts. When the electric actuator specifications was determined, the control torque is determined. Generally run in a predetermined time, the motor will not overload. But as the following conditions may lead to overload: one is the low voltage power supply and can not get the required torque, the motor stop running; 2 it is wrong to set torque limit, make its torque is greater than the stop, cause continuously produce too large torque, the motor stop running; 3 it is intermittent use, the heat generated by the savings, more than the allowed temperature of the motor to appreciate; Four is a torque limit institutions circuit for some reason fails, the torque is too large; Five is the use of the environment temperature is too high, the relatively decreased motor heat capacity.
in the past for motor protection method is to use a fuse, overcurrent relay, thermal relay, thermostat, etc. , but these methods all have advantages and disadvantages. For this kind of variable load equipment, electric device is not absolutely reliable measures for the protection of. So we must take various combinations, induces has two kinds: one is the increase or decrease of the motor input current judgment; The second is the motor itself heating situations. These two approaches, both the heat capacity of the given time allowance to consider motor.
usually, on the basis of the overload protection method is: the continuous operation of motor or inching operation over load protection, using a thermostat; The protection of motor blocked, the thermal relay; For short circuit accident, adopt the fuse or over-current relay.