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Solenoid Valve Terminology

Supplier: Process Systems
06 September, 2013

Now is a good time to explain some of the terminology used in order to help you with your selection.

Solenoid Valve Terminology

  • 2 way is a two port valve that turns the flow on or off.
  • 3 way is a three port valve that allows flow through the valve into a chamber, and then out through the valve exhaust. The universal function can also be used as a diverter valve.
  • 5/2 way is a five port, two position valve that will put a fluid or air into one end of a double acting device as well as allowing the other end vent to exhaust.
  • Zero Differential are solenoid valves that can operate under zero head pressure (do not need a differential pressure drop across the valve to work). This is made up of two categories, direct acting and coupled diaphragm.
  • Direct acting are solenoid valves that are activated purely by the electromagnetic forces in the valve and do not rely on the fluid pressure to assist. Hence they are used where little or no fluid pressure is available such as vacuum service or low pressure applications.
  • Differential operated are solenoid valves that do rely on the fluid pressure to assist in activating the valve. This helps in developing valves with larger orifices, higher pressures and smaller coils.
  • Normally closed (N.C.) means that when the solenoid valve is not energised the supply pressure port is closed off. In the case of 3 way valves the downstream port is open to the exhaust port.
  • Normally open (N.O.) means that when the solenoid valve is not energised the supply pressure port is open to the downstream port. In the case of 3 way valves the downstream port is closed to the exhaust port.
  • IP rating is an international standard to denote the degree of protection against water and solid objects. All of our electrical coils with DIN plugs have an IP65 rating. The '6' denotes a complete protection against items as small as dust and '5' is protection against low pressure jets of water from all directions.
  • Flame proof relates to the electrical part of a solenoid valve only (usually the coil and operator assembly) and is a way of making the valve safe to use in an explosive atmosphere. These valves must be installed in compliance to the wiring standards for this type of approval and in a zone compatible to the approved code and temperature rating.
  • D.I.P rating relates to Dust and Ignition Proof.
  • N.B. Bar relates to pressure: 1 Bar = 14.7psi = 100KPA = 1 atmosphere.