3-way solenoid valve

[vbug123]

Hi,

I am trying to understand a 3-way valve and get confused by the following information.
- A normally closed valve has ports A, P, and R. When de-energized, outlet A is vented.
- A normally open valve has ports B, P, and R. When de-energized, outlet B is pressurized.

Could someone explain "outlet A is vented" and "outlet B is pressurized"?

I am looking for a 3-way valve to switch between 2 fluid sources, can I use ports P & R as inlet ports and A (or B) as an outlet? Can I use either type mentioned above?

Thanks in advance.

 

[budt]

From the explanation you posted the person who wrote it was referring to using a 4-Way Valve as a 3-Way function.

I've suggested this many times to keep a customer from having to buy a 3-Way valve to keep in inventory as a spare.

A 4-Way valve can be used as a 4-Way, 3-Way or 2-Way function so one valve can be stocked instead of three.

Not necessarily cheaper up front but a lot less parts in inventory.

To use a 4-Way valve as a Selector Function you can use "P" and "R", with some valve designs. BTW "R" (Return) on most hydraulic manufacturers valves is "T" (Tank). On some valve designs the "T" Port has limited pressure, some as low as 200 PSI. On others they have the same pressure rating as "P" port. Pressurizing the "T" Port on many of the valves that have "Wet Armature Solenoid" design will blow the Coils off at their rated lower "T" pressure. Always check the catalog for individual port pressure ratings.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[hydtools]

Most likely:
Normally closed: valve not energized closes pressure port P, vents or connects output port A to return port R

Normally open: valve not energized connects pressure port P to outlet port A.

Normally closed and normally open refer to valve condition when 'off' or not energized.

Ted