Solenoid valves are widely used in our production. We first have a preliminary understanding of solenoid valves. Solenoid valves are composed of solenoid coils and magnetic cores, and are valve bodies containing one or more holes. When the coil is energized or de-energized, the operation of the magnetic core will cause the fluid to pass through the valve body or be cut off to achieve the purpose of changing the direction of the fluid. The electromagnetic part of the solenoid magnetic latching relay  valve is composed of fixed iron core, moving iron core, coil and other parts; the valve body part is composed of spool valve core, spool valve sleeve, spring base, etc.

The solenoid coil is directly installed on the valve body, and the valve body is enclosed in a sealed tube, forming a simple and compact combination. The solenoid valves commonly used in our production include two-position three-way, two-position four-way, two-position five-way, etc. Let me first talk about the meaning of the two positions: for the solenoid valve, it is live and power loss, and for the controlled valve, it is open and closed.

It is composed of a valve body, a valve cover, an electromagnetic component, a spring, and a sealing structure. The sealing block at the bottom of the moving iron core closes the air inlet of the valve body by the pressure of the spring. After energizing, the electromagnet pulls in, the sealing block with spring on the upper part of the moving iron core closes the exhaust port, and the airflow enters the membrane head from the intake port to play a control role.

When the power is lost, the electromagnetic force disappears, the moving iron core leaves the fixed iron core under the action of the spring force, moves downwards, opens the exhaust port, blocks the air intake, the airflow of the membrane head is discharged through the exhaust port, and the diaphragm* **Original location. In our oxygen production equipment, it is used in the emergency shut-off of the membrane regulating valve at the inlet of the turboexpander.

When a current flows through the coil, an excitation effect is generated, the fixed iron core attracts the moving iron core, and the moving iron core drives the spool valve core and compresses the spring, which changes the position of the spool valve core, thereby changing the direction of the fluid. When the coil is de-energized, the sliding valve core is pushed by the elastic force of the *spring, and the iron core is pushed back to make the fluid flow in the original direction. In our oxygen production, the opening and closing of the forced valve of the molecular sieve switching system is controlled by a two-position four-way solenoid valve, and the airflow is supplied to both ends of the piston of the forced valve. So as to control the opening and closing of the forced valve.