Indirect Acting Solenoid Valves

Indirect solenoid valves use the differential pressure of the media over the valve ports in order to open and close. Often, indirect solenoids require a minimum differential pressure of 0.5 bar to operate efficiently in the environment. However, this may vary depending on the brand of valve. Indirect-acting solenoid valves operate through a rubber membrane, often called a diaphragm, which separates inlet and outlet ports. The diaphragm contains a small hole which allows media to flow to the upper compartment. Above the membrane, there is a spring which ensures the valve remains closed. When the valve is energised, the pilot orifice is opened, causing the pressure above the membrane to drop. The pressure difference on both sides of the membrane means the diaphragm is lifted and media can flow from the inlet port to the outlet port.

Indirect solenoid valves can only be used for one flow direction, due to the structure of the valves. Indirect-acting solenoid valves are often used in applications where there is a sufficient pressure differential and a high desired flow rate. Common applications can include irrigation and car wash systems. However, depending on the material selection and operation of an indirect solenoid, they can often operate in hazardous areas, with either air, gas or water.