Design Guidelines

A Direct Acting Solenoid Valve is one in which a seat seal is attached to the solenoid core. In the energized condition, the seat seal orifice is opened; in the de-energized condition, the seat seal orifice is closed.

Direct Acting Two-Way Valves are shut-off valves with one inlet port and one outlet port. In the de-energized condition, the core spring, assisted by liquid pressure, holds the valve seal on the valve seat to shut off the flow. When energized, the core and seal are pulled into the solenoid coil and the valve opens. The electromagnetic force is greater than the combined spring force and the static and dynamic pressure forces of the medium.

Direct Acting Three-Way Valves have three port connections and two valve seats. One valve seat always remains open and the other remains closed in the de-energized mode. When the coil is energized, the mode is reversed. A variety of valve operations may be achieved based on the manner in which the fluid medium is connected to the ports.

Internally Piloted Solenoid Valves are used for switching higher pressures in conjunction with larger orifice sizes. Differential liquid pressure performs the main work in opening and closing the valve.

Internally Piloted 2-way or 3-way Solenoid Valves contain a diaphragm or piston which provides the seal for the main valve seat. When the pilot valve is closed, the liquid pressure builds on both sides of the diaphragm via a bleeding orifice. As long as there is a pressure differential between the inlet and outlet ports, a shut-off force is available due to the larger effective area on top of the diaphragm. When the pilot valve is opened, the pressure is relieved from the upper side of the diaphragm. The greater effective net pressure force from below raises the diaphragm and opens the valve. Internally piloted valves often require a minimum pressure differential to assure satisfactory opening and closing.