2-way, 3-way: Describes the number of pipe connections to the solenoid valve.Way may be replaced by the word port.

2/2 valve Describes the number of ports or ways and the number of positions - 2/2 is a simple valve with two ports - an inlet port and an outlet port. In operation it has two positions - open and closed. 3/2 valve A valve with three ports - for a normally-closed valve this would be an inlet port, an outlet port and an exhaust port. In operation it has two positions - 1) the inlet is closed and the outlet and exhaust port are linked. 2) the inlet is open and linked to the outlet port and the exhaust port is closed.

Media: The liquid or gas that the valve is being used with.

Valve body: This is the main part of the solenoid valve where connections, seats, orifices or working orifices are located. Most of RPE solenoid valve bodies are made of thermoplastics but other materials are used for special applications, ACL produce their solenoid valve bodies in brass or stainless steel.

Seat (or valve seat): The surface of the orifice that the seal bears on to close the valve.

Orifice: An opening normally formed inside the valve body which is opened and closed by the seal as the armature moves under the influence of the solenoid coil and the return spring.

Fixed Core: Is positioned at the end of the armature tube and completes the magnetic circuit. It is generally made of magnetic stainless steel, frequently included the fitting used to secure the coil to the valve.

Phase Displacement Ring (or shading ring): This is generally made of copper or silver (for de-mineralised water) and is mounted onto the fixed core surface to prevent noisy oscillations when the valve is used on an a.c. supply.

Armature Tube: Generally made of nylon, brass or stainless steel, it provides a guide for the moving armature. It Is generally assembled with the fixed core and the coil securing thread.

Armature: Made of magnetic stainless steel, the armature moves under the influence of the magnetic field generated by the solenoid coil. It slides inside the armature tube. The valve seal will normally be attached to one end for 2-way solenoid valves or one at each end for 3-way valve.

Armature (or Return) Spring: It is used to keep the armature in position and bring it back after the electromagnet action.

Seal: It is generally produced in a synthetic rubber the seal is mounted onto the armature to close the valve or the pilot orifice. The type of material used is normally chosen to suit the type of media the valve is being used with.

Diaphragm: In the servo-controlled solenoid valves, it is used as a servo-control which opens or closes the main orifice of the valve body when operated by an electromagnet pilot and by pressure.

Insert: Used as a supporting element for the diaphragm, it balances the opening and closing pressure through the filling and discharge pilot orifice.