Working Principles and Functions of Solenoid Valves in Industry

Basically solenoid valves work by utilizing electromagnetic force, this force makes the solenoid valve open and close on a line followed to the use of electromagnetic forces, solenoid valves are often also referred to as Electromagnetically Operated valves.

The solenoid valve is a type of automatic valve, and is now widely found in the market because of its attractive performance efficiency. Because, if initially the valve is closed, after the application of electromagnetic force the valve will lift the plunger which makes it open.

This is a simple physics invention, utilizing a hollow cylinder of thin wire. When current is passed through the wire, the system acts as a magnet which opens the plunger. The magnetic field can be controlled by the amount of current that is passed, the higher the current, the higher the magnetic effect produced.

Solenoid valve parts

• The solenoid valve body is the main part of the valve that is in direct contact with the pipe, the valve body is filled with the entire assembly of the solenoid valve in it.
• The valve inlet port is the point/direction of fluid entry.
• The outlet port is the point / direction for the liquid to go to the next process.
• The coil is a long thin wire wound around a magnetic core.
• The plunger is the part that will stop or allow the flow to go on. Plungers are usually made of ferromagnetic material with a cylindrical shape, and their performance will be controlled based on the amount of current received by the solenoid valve.
• The solenoid coil is the part of the valve that will energize, its shape is a hollow cylinder made of thin wire.
• The spring is the part that will keep the plunger in position when current is not flowing from the solenoid. When current is applied, the plunger immediately opposes the action of the spring and opens/closes the flow.
• The orifice is the part of the hole where the fluid will flow from the inlet to the outlet. In the closed position, the plunger will stop the flow by blocking the orifice.

Because it is an automatic valve, an operator must know when the valve should open or close. The control process is assisted by a sensor on the solenoid valve, when an operator needs fluid flow, the sensor will provide current to the solenoid and the electromagnetic force will affect the plunger to lift upwards, as well as against the compressive force exerted by the spring. Sensors will greatly assist operators in controlling the solenoid valve and the desired amount of flow in a production process.

Types of solenoid valves

1. Direct solenoid valve

Type This type of valve is the simplest of all solenoid valves, the direct solenoid valve does not require an external force to open and close the valve. However, this type of valve has a superior operating speed than other types.

In this type of direct solenoid valve, usually there are two types of operating conditions, namely NC as a closed condition and ON as an open condition. These limited operating conditions make the type of solenoid valve directly unable to control the percentage of the flow.

2. Pilot operated

Solenoid valve type This is a more complex type of solenoid valve, because it includes a diaphragm. The function of adding a diaphragm is to separate the inlet port and outlet port, so that the flow control accuracy can be maintained. The advantage of this type of valve is that the percentage of flow that will come out of the outlet port can be controlled directly.

3. Type of two-way solenoid

Valve This type of valve contains two openings (outlet ports) for fluid flow, and the working principle is almost the same as the direct type solenoid valve.

4. Type of three-way solenoid valve

It contains three openings and two holes in the valve. The orifice opens and closes alternately. For this type two different designs are available, (1) Two inlet opening ports and one line out port, and (2) line out ports and one inlet port. The first design is usually used to mix two different liquids, and the second design is used to separate one stream into two.

Solenoid Valve Applications

• In Industrial refrigeration systems
• where compressed air is not used
• In vacuum systems
• In automobile combustion systems
• etc.

Advantages

• Quick opening
• Low power consumption
• Compatible with both AC and DC currents
• Can be installed vertically and horizontally

Disadvantages

• Very sensitive to voltage
• Magnetic field affects openings valve and closure
• Need to replace coil after some time