good evening. maybe you all can help me with something. i need to build something at work. basically it will be a control center for air actuated steam valves used to heat tankers. as it is NOW, you set a timer, the valve opens for that amount of time, then closes. what i need is to be able to set a timer, and have that valve open for XX minutes, then close for XX minutes, until time expires. the closest i have found is a drain actuator for air compressors, but the minimum and max time settings don't match my needs. what i need is from 5-40 minutes on both the open and close events. IOW, set timer for two hours, on time for 10 minutes, off time for 20 minutes. it will pulse 4 times, then the timer will expire.
it would be AWESOME if someone knew of a way to do this entirely pneumatically. i can run power, but if i don't need to, i wont. the current "constant open until time expires" main timers are air only, so if i can keep that, great. last result is a micrologix PLC, 120v service, and MAC valves, but that's overtly complicated for what i'm trying to do, and would be over budget on time and materials.
here's a link to the compressor drain to give a general idea of what i need, just with more flexibility.
http://img.diytrade.com/cdimg/154248/2300766/0/1150435554/Timer_Drain_Valves.jpg
(someone feel free to hotlink that cause i suck)
thanks fellas,
-J0N
Why not a 24/7 digital programmable appliance timer w/ MAC 3 or 4-way valves. Up to 20 on/ off events per day (the one I seen), plus adjustable durations.
It's been a long time since I worked with pneumatic logic on explosives manufacturing equipment. Your needs would be pretty easy to solve with the stuff we used then. It was all Festo pneumatic logic control components. I know Festo still exists today, you might try finding their closest distributor.
oldtin
UberDork
6/8/15 10:07 a.m.
You might tryJohn or Ed at kelly pneumatics. They were super helpful in designing a air over hydraulics clutch actuator for me with proportional control. A timer sounds easy.
I don't know how your valves work but if its something like energized = open, not energized=close, then I think a simple programmable timer should work. I used a cheap programmable timer with ~16 available events. I used this one when I was working on a solar water pump that we wanted to cycle off and on and be able to vary the duty cycle. Sounds like it would be a solution for you.
http://www.amazon.com/dp/B0090MTLFO/ref=pe_385040_30332200_TE_item
the valves are air actuated, there is no power out in the steam bay. just steam and 100 psi micro lines. the current setup is an air operated mechanical timer that opens the valve for xx minutes then closes it. i need to interrupt that process with an 'on for xx mins, off for xx minutes' pulsing device.
ill get in touch with festo and kelly pneumatics, thanks for that.
-J0N
