How Solenoid Valve Works

Valves operate in different mechanisms. Most valves can be manipulated manually by turning but there are valves operating manually by the drive of temperature and pressure. Manually operated valves are used in simple conveyance applications involving non-abrasive fluids like water and oil. However, this type of valve is no longer applicable for large-scale applications using bulky pipelines. Large automatic or power driven valves are used instead.

Solenoid valves are an example of valves used for regulating high fluid flow. This type of valve consists chiefly of a solenoid, a long, flimsy loop of wire that produces a strong magnetic field when applied with current. The electromagnetic field turns the solenoid into a magnet that can create a controlled linear force. In some engineering fields, this refers to various transducers that convert electrical energy to mechanical energy.

Other important parts of a solenoid valve include the following: piston, plunger, springs and diaphragm. The piston is the metal tube containing the plunger. The solenoid turns it into an electromagnet to pull up and release the plunger inside. It also serves as a dividing surface between the plunger and the coil. Like all other parts of the valve, except for the diaphragm, the piston is made of hard corrosion-resistant metal.

Solenoid produces weak magnetic field that can pull the plunger up a bit. But when applied with direct current, it produces a very strong magnetic force that can lift the plunger to a desirable elevation which will allow the fluid to flow through the ports. Large solenoid valves like the Spence E5 Valve are made of huge coils that require a substantial amount of current to produce the necessary magnet.

The plunger is partially suspended within the piston through springs on both its ends. When the coil is applied with the current, it moves up and pulls the diaphragm upward. This allows the fluid to enter the ports. When the source of electricity is shut down, the plunger goes back in place and covers the port. This mechanism is employed in valves like the Spence E5 Valve.

The amount of fluid to enter the port is determined by how long the coil is applied with the direct current. When the pipeline is closed and no fluid is flowing, the plunger is down and the power supply is shut down. This mechanism presents several advantages including haste in response to fluid flow and does not require direct human intervention. This is the reason why solenoid valves like Spence PRV are widely used.