// Catalogue

3/2 Way Valve for Pressurize,Vent Cycle

3/2 way valves have three ports and two positions. They send pressure to a line, then shut off the supply and vent that line when they switch back. TSA Hydraulics Engineering supplies them within the Directional Control family of our Valves range, for compressed air and hydraulic circuits.

That third port is quietly a safety feature. When the valve switches off, the line empties instead of holding trapped pressure, so a cylinder or actuator relaxes rather than staying loaded. Match the replacement carefully to keep it that way. Share the model code and coil details, and we will supply a factory original or a matched equivalent.

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// Buying guide

How a 3/2 Way Valve Works

The three ports are the supply, the working line and the exhaust or tank return. On pneumatic valves, they are usually marked 1, 2 and 3.

In one position, the supply connects to the working line and the actuator moves.
In the other, the supply is blocked and the working line vents to exhaust.

A 2/2 way valve can only open or close a line. The extra exhaust port is what lets a 3/2 valve release the pressure as well.

Normally Closed or Normally Open?

Normally closed: the working line stays vented until the valve is switched. This is the most common type, because the actuator stays at rest if the power fails.
Normally open: the working line stays pressurised until the valve is switched. It is used where an actuator must stay engaged during a power cut, such as some brakes and clamps.

Common Jobs for 3/2 Way Valves

Driving single-acting and spring return cylinders
Opening and closing spring return actuators on process valves
Sending a pilot signal to shift a larger valve
Dumping air from a machine for safe maintenance
Selecting or diverting flow between two lines in hydraulic circuits

For double-acting cylinders that must be driven both ways, step up to 4/2 or 5/2 way valves.

Poppet or Spool?

Poppet: seals tightly, tolerates some dirt and switches fast. It is popular for pilot and dump duties.
Spool: balanced against pressure, so it needs less force to shift, but it allows a small internal leak.

NAMUR Mounting for Actuators

Many quarter turn valve actuators in water and process plants carry a standard NAMUR interface. A NAMUR 3/2 valve bolts straight onto the actuator with no tubing in between, which cuts leaks and saves space. Many NAMUR valves can switch between 3/2 and 5/2 operation with a simple plate, so check which mode yours runs in.

Exhaust Tips

Never block the exhaust port, or the actuator will not return.
Fit a silencer to cut noise and keep dirt out.
Fit a speed controller on the exhaust to slow the return stroke.
To vent large cylinders quickly, add a quick exhaust valve close to the cylinder.

3/2 Way Valves Specifications to Check

Port size and thread, or a mounting interface such as NAMUR or a subplate
Normally closed or normally open
Poppet or spool design
Actuation: solenoid, air pilot, manual or mechanical
Coil voltage, AC or DC, and the connector
Pressure range, and the medium: air or oil

Why Buy From TSA Hydraulics Engineering

As a 3/2 way valves supplier, we match the port layout, normal position and mounting, not just the thread size. You get OEM or equivalent options, and help sourcing 3/2 way valves replacement parts such as coils, silencers and seal kits. We tell you upfront whether a valve is genuine or an equivalent.

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