A solenoid valve is an electromechanically controlled valve that eradicates the need for an engineer to operate the valve manually. Usually, solenoid valves are used whenever flow of media has to be controlled automatically. An increasing amount of plants are taking advantage of the solenoid valve, as a variety of different designs are available, enabling the valve to be selected to suit the application in question. In this article, MGA Controls discusses solenoid valve working principle and explains the construction of a solenoid valve.
Construction of a solenoid valve
A solenoid valve is a control unit that is electrically energised or de-energised to allow for the shut-off or release of flow. It is made up of two main parts: the solenoid; an electric coil with a movable ferromagnetic core in its centre, and an iron plunger that is allowed to move through the centre of the coil. When the coil is energised, the resulting magnetic field pulls the plunger to the middle of the coil. A spring is also required to return the plunger to its original position.
Operation of a solenoid valve
So, how does the solenoid valve function? When the solenoid valve’s iron plunger is in rest position it closes off a small orifice. An electrical current then runs through the coil, creating a magnetic field. The magnetic field then places force on the iron plunger, resulting in the plunger being pulled towards the centre of the coil opening the orifice. This is what in turn controls the flow, allowing for the shut-off or release of media.
Types of solenoid valves
There are three main solenoid valve technologies: direct acting, in-direct acting and forced-lift piston type. Each of these solenoid valves work in slightly different ways and are suited to different applications.
- Direct-acting solenoid valves – Direct acting solenoid valves require no differential pressure to remain in their rest position. They are robust valves that can be used in both a process line for simple isolation or for safety purposes.
- In-direct acting solenoid valves – In-direct acting solenoid valves do require a differential pressure across the inlet and outlet to allow them to remain in their rest position. These valves are best used if pressure levels are within the parameters specified in the specific model’s datasheet and IOM instructions.
- Force-lift solenoid valves – Force-lift valves are utilised in extremely high-pressure applications where neither of the above valves can handle the elevated pressure. This valve houses a larger and more powerful coil to open and close the valve’s orifice.
MGA’s range of solenoid valves
At MGA Controls we have a huge range of solenoid valves from an array of leading manufacturers including, IMI Precision, Herion, Buschjost, Bürkert, ASV Stubbe and Maxseal. Our range of solenoid valves vary in size, configuration, price, material and application specialism, so you can find the perfect valve for your application.
At MGA, we also carry ATEX approved solenoid valves for use in hazardous areas, along with high-pressure solenoid valves for extraordinary applications. To view our full range of solenoid valves, click here.
For more information on the operation of a solenoid valve or to discuss our full range of solenoid valves, call 01704 898980 or get in touch via email on [email protected]