Solenoid valves are a useful solution for a variety of industrial applications. These valves are often selected for use wherever fluid flow has to be controlled automatically, and as industry turns more and more to automatic rather than manual processes, this means we are starting to see an increase in their usage in a number of industrial fluid and gas control systems.
What does a solenoid valve do?
A solenoid valve functions by either opening or closing an orifice in a valve body, which allows or prevents flow through the valve. Within the this type of valve, a plunger opens or closes the orifice by raising or lowering within a sleeve tube by energising the coil inside the valve.
Many applications make use of solenoid valves to replace manual valves and allow for better remote control.
Its assembly has three key parts. These are:
- A coil,
- A plunger,
- A sleeve.
In a closed valve, the plunger return spring holds the plunger against the orifice to prevent the flow of liquids or gas, depending on the application. Then, as the solenoid coil is energised, the resulting magnetic field causes the plunger to raise up which enables the liquid or gas media to flow through the valve opening. However, if the solenoid coil is energised in a normally open valve, the plunger will fall to seal off the orifice and therefore prevent media flow.
Why do we use solenoid valves?
This type of valve is necessary in most flow control systems. If you need to stop or start the flow of a liquid or gas in a circuit to control the flow of fluids in a system, you need a solenoid valve. By being solenoid actuated, solenoid valves can be positioned in remote or hard to reach locations, and can be conveniently controlled by simple electrical switches rather than manual action.
Solenoid valves are perfect for use in a variety of application areas as they can be used to shut-off, release, dose, distribute and mix fluids with ease. Solenoid valves also offer the additional benefit of safer and faster switching, with a long service life, high reliability, a limited need for control power and a compact design.
What types of solenoid valves are there?
There are five different types of solenoid valves for use in liquid and gas control applications. These are:
- Direct acting – In this type of solenoid valve, a coil magnetically opens the valve in direct action, to lift the shaft and seat of the valve without needing to rely on outside pressure.
- Pilot-operated – In this type of solenoid valve, the solenoid activates a much smaller ‘pilot’ valve that opens up to a larger valve operating at a much higher pressure. These valves are well suited to releasing large volumes of gas, liquids, steam and more.
- Two-way – In a two-way solenoid valve, each of the two ports are alternately used to allow flow through the valve, or to close it off. Two-way solenoid valves are designed to be ‘normally open’ or ‘normally closed’ in their operation. If a valve is normally open, it remains open until some type of current is applied, however if a valve is normally closed, it remains closed until a power source causes it to open.
- Three-way – Three-way valves come with three ports, and are commonly used when alternate and exhaustive pressure is required for the valve to operate. One everyday example of a three-way solenoid valve use is a dishwasher.
- Four-way – These valves have four, or more, port connections. They are commonly used in conjunction with a dual-acting cylinder or actuator.
What applications use these types of valves?
So, now that we have learned about how solenoid valves work and the various types of solenoid valves available on the market, now is a great time to find out more about the applications that solenoid valves are used in.
As solenoid valves are used to control the flow of a liquid or gas media within an industrial or domestic application. This is what makes them suitable for use in a multitude of environments, such as:
- Air compressors – Solenoid valves are used to control the flow of compressed air, as a gas, through the valve when the compressor is in operation. When the tank reaches the required pressure, the pressure switch stops the motor and checks the valve to keep the air inside the tank.
- Manufacturing – Solenoid valves are often implemented into industrial manufacturing systems to control machines and the flow of liquids. This includes dosing, mixing or restricting the flow of liquids or gases into a system. One prime example of solenoid valve use in manufacturing would be in the manufacturing of beverages, in which a solenoid valve will be used for filling purposes on a production line.
- Agriculture – These types of valves are invaluable for use in controlling irrigation systems such as automatic sprinklers and motorised farm machines. Here, solenoid valves work to control the flow of water and operate a sprinklers function autonomously.
- Automotive – Solenoid valves are used in a variety of automotive applications. They are usually used to regulate the flow of automotive fluids such as oil, brake fluid and fuel. In some instances, automotive fluids need to be reduced, but not shut-off completely. In these cases, a variable solenoid valve may be used to regulate the flow of a medium.
- Home heating and power – Solenoid valves are widely used in home heating solutions, from applications such as the kitchen tap, to your boiler, solenoid valves are able to open and close to be able to let in cold or hot water as required. Given the high flow rate of a home heating system, a pilot operated solenoid valve is usually the most suitable.
- Vacuum systems – Solenoid valves are widely used in vacuum pump applications, as they need minimal pressure levels, which makes them best suited for vacuum pump applications. A vacuum solenoid valve is designed to be leak-free, which eliminates the risk of a loss of pressure.
Which industries use solenoid valves?
So, as you can see, solenoid valves are used by a variety of industries and industrial applications. From industrial to domestic applications, solenoid valves are an excellent choice when you want to control the flow of a liquid or gas, with limited need for human intervention. With a range of solenoid valve options available on the market, there is bound to be one to suit the needs of your application!