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Valve Porting Explained

Valve porting pertains to the usability of the port and the direction of flow through the valve in different positions. There are two key points we will cover. First, the usage of the port—can we physically connect to the port? And second, the flow direction that the valve must accommodate for the application.

Fully Ported

Fully Ported ValvesA “fully ported” valve is any valve that you can physically capture or plumb to all the ports. This does not mean that all the ports are necessarily threaded, but this does mean that the flow path can be captured via a specific method opposed to a vent hole that goes to atmosphere.

Fully ported valves are ideal for applications where the media needs to be plumbed, for example: in clean rooms where all gases must be vented external to the room. Clippard’s ET-2-12 with threads on the inlet port and threads on the outlet port could be referred to as fully ported since all the ports on the valve can be plumbed, but the ET-3-12 is not fully ported as the exhaust path is vented through small holes in the valves cap. Hence Clippard’s offering of the ETO-3-12 fully ported version of the ET-3-12.

It is important to note that “fully ported” does not specify that all ports can be pressurized, only that they can be ported.


Bi-Directional ValvesA bi-directional valve is a 2/2 valve that is not sensitive to which port is the inlet or the outlet. In Europe this is referred to as a bi-stable valve. Bi-directional valves are necessary for demanding applications where the higher pressure differential could be on either the inlet or the outlet.

A common ball valve is a simple example of a valve that doesn’t care what side the pressure is coming from and works in either direction. This valve would be known as bi-directional.

The opposite valve to this would be a check valve, which flows in a single direction only.

Universally Ported

What about the possibility of a valve with more than two ports that is fully ported and bi-directional? This would be a universally ported valve. A 3-way universally ported valve can be configured for six functions, such as: 3/2 normally-closed, 3/2 normally-open, 2/2 normally-closed, 2/2 normally-open, selector, or even diverter.

It is important to note that not all fully ported 3/2 valves are universally ported.

Universally Ported Valves

For help selecting the best valve for your application, call 877-245-6247 or contact your local distributor.

By Mike Kettering • Technical Sales Specialist • Clippard