Electromagnetic coil for direct shut-off valve control
Any standard size of the direct shut-off valve must work with a feedback drive system that returns the device to its original position. Most often, an electromagnetic drive is used for these purposes, and hydraulic valves are used only for very large expenses of the working medium.
Purpose of the control valve
The electropneumatic valve of the feedback system receives an electrical signal (AC or DC voltage), opening/closing as a result the air supply that flows to the direct shut-off valve.
The composition of such a tracking system includes:
- Electromagnetic coil;
- The piston;
- Return spring;
- Body.
When energy is applied to the coil, it attracts the piston and causes it to move inside the valve body. This, in turn, opens or closes the openings inside the valve body, allowing the air flow to control the pneumatic actuator. When the power supply is turned off, the piston spring returns it to its original position and turns off the air supply to the pneumatic drive of the main unit.
To choose the right solenoid to drive a direct shut-off valve, you need to know what is actually going on inside the solenoid and what is going on inside the actuator.
Ways to implement a feedback system
Most pneumatic actuators using these valves are either double-acting systems or spring-return systems. Many pneumatic actuators consist of one or two pistons inside a cylinder connected to a rod or gear that controls the valve.
There are also diaphragm drives where a rubber diaphragm with a spring is used. It is attached to the stem, which controls the valve. Spring return actuators have springs at the ends of the pistons that return the pistons to a certain position when air is removed from the drive.
The operation of the direct shut-off valve is that when air is admitted to one side of the piston, air must be released from the opposite side. At the same time, throttling of the flow from the piston or diaphragm side must be ensured so that the drive of the direct shut-off valve returns to its original position.
It is most rational to use special direct-mounting solenoids for control in order to eliminate the need for additional fittings. Remote-mounted electromagnets are installed either on the valve itself or next to it. The use of such tracking systems ensures stable operation of the valve, even if the actuator is in difficult operating conditions.