Solenoid valve - device and principle of operation

The solenoid valve is an electromechanical device that is controlled by an electric current. The latter passes through an electromagnet (coil wound around the core), resulting in the formation of a magnetic field. By its action it can open and, on the contrary, close the solenoid valve.

In general, this mechanism is used to regulate the flow of liquids and gases. Most often it is used in the agricultural sector (irrigation systems) and for industrial purposes. Also it is irreplaceable in cars.

The structure of this mechanism includes the following parts:

• Solenoid coil.
• Pilot hole.
• Plate of the solenoid valve.
• Closing spring.
• Anchor the valve coil.
• Main flow hole.
• Diaphragm of the membrane amplifier.
• Aligning flow hole mechanism.
• Forced valve opening system, which is activated by means of a spring.

Solenoid valve of the 2109th VAZ and its operation principle

In this mechanism, a certain mechanical force is generated by the electromagnetic coil (it converts electricity into magnetic field energy.) As a result, the solenoid valve changes its position - it can be closed and opened. At the inlet, this part has an inlet pipe through which gas or liquid flows into the mechanism.

The VAZ solenoid valve includes a rubber (less often - plastic) membrane. It is pressed into the inlet pipe and can regulate the flow of the incoming liquid. Its front side consists of a sealing ring, which at the right time prevents the flow into the mechanism. The membrane is most often attached to metal springs fixed on the back of the valve.

The position of this mechanism depends on the metal rod that is placed under the coil. When the latter is excited, the rod is retracted under the influence of a magnetic field, and at that time a sealing ring leaves the membrane. Thus, the flow of gas or liquid flows into the solenoid valve. When the coil is disconnected, the membrane is pressed against the seal surface by the inlet under the action of a spring.

Pressure in the valve

This part, unlike conventional pumps performing a similar function, does not have any mechanical devices by which the gas flow passes into the system. That is why it is so important to observe the differential pressure at the inlet and outlet of the valve. In order for the liquid to pass through the solenoid valve, a higher pressure in the inlet line must be formed than at the outlet. If this value is the same at both ends of the mechanism, the thread will no longer pass into the working environment. This principle of operation has the majority of modern valves, except direct-acting devices (they can transfer gas and liquid, regardless of the pressure in the pipelines).