http://www.irtools.com/ir_pdfs/Fluid%20Technologies/ARO%20Fluid%20Products/Valves%20%26%20Cylinders/Premair-EnEsFr.pdf

what does the diagonal arrow in the lefthand box mean? Does it mean that the "exh" and "in" inlets will vent to atmosphere when deactivated?

12/6/2008 4:13:41 PM

no. that entire box is the symbol for a 3 way valve. since it's on the left, that means it's a normally closed valve. since there are two boxes, that means it's a two position valve. the little box on the far left with the / in it stands for solenoid. the little upside down Z is a spring.

clear as mud? i'll try to explain better if needed. reading/translating valve schematics can be tricky. it's one of those things that's really hard to learn and figure out initially, but once you've got it you kick yourself it's so easy. at least that's how it was for me.

12/6/2008 4:58:21 PM

ah.. makes perfect sense now it's just the same diagram side-by-side, one without labels and showing what happens when powered. thx!

12/6/2008 6:03:51 PM

A quick google search turned this up:

http://www.age.psu.edu/tae/902/hydraulic_foundations.ppt

Slides 36-40 show what is going on with a normal, open center, hydraulic valve.

[Edited on December 6, 2008 at 7:27 PM. Reason : ]

12/6/2008 7:27:34 PM

that valve is made right here in NC, used to work / co op there

12/6/2008 8:03:13 PM

^^nice find, but he's dealing with a pneumatic valve. very similar to hydraulic in most cases, but there are enough differences to where it would be worthwhile to learn this using a pneumatic tutorial of some sort (if he even cares).

[Edited on December 7, 2008 at 2:18 AM. Reason : .]

12/7/2008 1:51:58 AM

Hell, we used to use the 3-way air solenoids quite a bit on pneumatic actuators...Energize, and the air path goes from in to out. De-energize, and the inlet is closed, and the pressure at the out side exhausts to atmospheric. We used them on spring-loaded damper actuators where you only need pressure to actuate; the spring force returns the actuator to the default position when pressure is released.

12/7/2008 2:00:26 AM

^^I wasn't saying it was the same, that was just to show how the schematic is block is the valve in a different position. A lot of people I run across have trouble with it until they see a schematic that has been moved to show the different positions.

there are some good animated JIC valves, but I didn't see them with a quick search and didn't feel like looking for a while

[Edited on December 7, 2008 at 8:45 AM. Reason : ]

12/7/2008 8:39:47 AM