Solenoid Valves

3/2 Way Direct Acting Solenoid Valve Function

3/2 way Direct Acting Solenoid Valves.

3/2 Way Direct Acting solenoid valves utilise the armature movement as the direct 3 way direct acting miniature brass solenoid valvemeans to Open / Close the inlet or exhaust ports of the solenoid valve.

3/2 way normally closed solenoid valve Inlet pressure is typically through P1, so when the solenoid valve de-energised the inlet port P1 is closed i.e. the armature is down and sealing against the inlet orifice and outlet top orifice is open thus the media at the outlet Port 2 is allowed back through and up through the exhaust Port 3.

When energised the coil lifts the armature away from the sealing orifice directly Opening Port 1 and also directly closing Port 3, allowing full flow of media through the valve from inlet pressure P1 to outlet P2. 

3/2 way normally open solenoid valve inlet port 1 is open to outlet port 2 with exhaust port 3 closed, when powered / energised inlet port 1 is closed and outlet port 2 is allowed to vent through exhaust port 3. However, in some instances a 3/2 way normally open solenoid valve configuration will use port 3 as the inlet port and port 2 as the outlet, thus making port 1 the exhaust port. This configuration is quite common and offers a reduced cost way of obtaining a 3/2 way, normally open function.

3/2 way universal solenoid valve has the added advantage of being able to accept inlet pressure at any port and control flow in any direction. The functionality of this valve works on the same principles as normally closed or open versions but does not have the limitations of flow directly associated with other designs. This is very beneficial as the inlet, outlet and exhaust ports can be piped up in any configuration to suit the application, so can be used as normally closed, open or as a diverting valve.

Benefits of Direct Acting Solenoid 3/2 Valves.

These 3/2 direct acting solenoid valves do not require any pressure differential to operate and are usually low cost, compact and with a small coil offering reduced power consumption, reduced heat and are ideally suited for actuator and cylinder control applications. These 3/2 way direct acting solenoid valves are suitable for most general purpose media applications and can be found in either Brass, Plastic and Stainless Steel bodied variants.

Other associated names for 3/2 Direct Acting Solenoid Valves:

3/2 Direct Acting solenoid valves, Spool solenoid valves, Poppet solenoid valves, Miniature 3 way Solenoid Valves, direct operated control valves, valve control valves, pilot solenoid valve and 3 way plunger type solenoid valves.

Miniature 3/2 way solenoid valves.miniature 3/2 solenoid valve manifold system

3/2 way miniature brass direct acting solenoid valve

Here on the left-hand side is a picture of a typical miniature 3/2 way brass direct acting solenoid valve. The port sizes range from 1/8, 1/4 or 3/8 thread with the exhaust port being 1/8 BSP male in all cases, however some 3/2 solenoid valve offer M5 exhaust as can be seen on the right hand side modular manifold system. Pressure ranges vary, however all will work from vacuum upwards to either 10 or 15 bar depending on the orifice size and coil rated power DC measured in Watts and AC measured in VA Volt-Amps.

Standard 3/2 Way Solenoid Valves.

3 way universal ATEX EExdIICT6 flame proof solenoid valve

Not all 3/2 way direct acting solenoid valves are miniature versions, here on the left-hand side we have a 3/2 way universal function solenoid valve with port sizes from 1/4", 3/8" and 1/2"  BSP or NPT thread.

This particular model has been fitted with the ATEX EEx d II C T6 flameproof enclosure which is required for hazardous area applications where there could be flammable or explosive gases, vapours or dusts in the surrounding space. These models are typically available with manual reset and manual override options.

3/2 Way Solenoid Valves with Manual Reset

The solenoid valve is energised to the open or closed default state, when power is removed or lost even for a short time and then reapplied the valve will remain in the default position until an engineer or user physically pushes or turns the reset lever or knob to allow the solenoid valve to change its state. Upon power failure, the solenoid valve will automatically drop back to default state. From the default position, the valve will need to be energised and manually reset again to allow the solenoid valve to move into its energised position. This is particularly useful if there has been a short power failure and systems need to be checked before main process valves controlled by this 3/2 solenoid valve can be allowed to reopen again.

3/2 Way Solenoid Valves with Manual Override

A 3/2 way solenoid valve with a manual reset function is a manually operated system, typically a turn knob or lever system, that will mechanically put the 3/2 way solenoid valve into the energised position regardless of power supply. This is particularly useful is the main system valve being controlled needs to be actuated for installation testing when no power is available or to allow systems to continue working when no power is available.


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