Timed pneumatic circuit.

F

Fellhoelter

Joined
Dec 29, 2005
Messages
1,367
I need to build a timed pneumatic circuit.

All I want it to do is fire a blast of air every several minutes.

Anywhere from 5 to thirty minutes, with just a few seconds duration.

I don't care if is electrically or pneumatically controlled.

Anybody know a simple, relatively inexpensive way to do this?
 
you could setup a timer relay that will "close" every 5-30 minutes to do what you want. When the timer goes off, I believe you can have a duration set on some of the models I use at work that allow for seconds/mins. Then looping through continuously.
 
I've done this with an adjustable timer relay and a solenoid valve. The relay was about $60 from MSC, I already had the valve.


edit, oop, I see Hotrod beat me to it. I forgot to mention it forms an infinite loop.
 
forgot to add:

these two timers, should work, especially the last one as it's a repeat cycle timer.

http://www.grainger.com/Grainger/DAYTON-Time-Delay-Relay-6A855

http://www.grainger.com/Grainger/OMRON-Repeat-Cycle-Timer-2A179 (I use this model at work as well as others designed like this one.)

here is the base/adapter needed:

8 pin adapter for second timer: http://www.grainger.com/Grainger/DA...cm_sp=IO-_-IDP-_-RR_VTV70300505&cm_vc=IDPRRZ1
11 pin adapter for first timer: http://www.grainger.com/Grainger/DA...m_sp=IO-_-IDP-_-BTM_BTB05209020&cm_vc=IDPBBZ2

forgot to mention, if you've never used these bases, they are numbered 1, 2, 3, 4, 5, etc. on each terminal post. If you need a wiring diagram for them, it should come included, if not, I'll dig one up at work and post it for you.

Regards,
Christopher
 
Last edited:
The timer relays above look rugged and simple.

125 for the timer

& maybe 50 for a valve
http://www.grainger.com/Grainger/INGERSOLLRANDARO-Miniature-Direct-Acting-2G487?Pid=search




Are those cheap enough for you ?

You can likely use a plug pack, few transistors, maybe a 555 timer a few resistors, a capacitor and a relay
maybe $10 ish plus the valve.

I'm not smart enough to write up the circuit for you, but if you define your needs in voltage, current, timing and such
and pick out the valve first, maybe somebody on a forum like this would lay out out for you.

http://forum.allaboutcircuits.com/index.php
 
Got some stuff on order.

I'll get it sorted.

This is simple.

I've don a TON of things like this in a past life, but we always used PLC's.

Never used one of these timers before.

Timer and valve from McMaster about $100.

I have a McMaster order building already, and a return sitting here, so I'm not out anything if I don't receive what I am expecting.
 
Ok, I've been investigating these timers.

Anyone know what "flicker" means?

Many of them have flicker on, or flicker off...
 
Flicker is a short period in the on or off state and then it returns to the original state. The Omron timers we use at the day job have the flicker and it is a very short flick.

Charles
 
Flicker timers are for short duration, repeating event use.
Say you want the timer to fire a carbide cannon every hour to scare the crows from your corn field. You set the flicker timer to one hour, and every hour it turns on for a moment to energize the igniter circuit. Then it immediately turns off and waits for another hour.

A two event timer is one that has two timer circuits and one turns the other on. Timer A runs for its set period, and then energizes timer B...which runs for its set period and then energizes timer A again, etc.
This is good for a setup like you want where the timer waits for one hour, the turns on the air for 5 minutes, and waits another hour.

Ebay is a great source for timer relays.
 
If I were going to do this I would probably use a Stamp. A Stamp is a programmable microcontroller. In other words a computer in a chip. I would probably use a 10 position rotary switch so I could have 10 presets.
The 10 settings would be programmed into the Stamp when initially programmed via a computer (10 settings whatever you want). Next put Stamp in a small project box with a 9 volt and a 10 position rotary switch hooked to Stamp. THen one line would be output activating whatever needs it, Stamps usually put out 5 volts I believe. I usually have the Stamp activate a 5v relay by forward biasing a transistor. I would be happy to set something up for you if your current course of action does not pan out. Would be a easy project for me and all you would have to buy is the Stamp (USually about $39 or so)
WHat would this thing ultimately be activating???????
CW
 
All I am trying to do is shoot a blast of air into my tumbler every few minutes.

I vibratory tumble a lot of parts on occasion, this week there were 300 parts that went through the system.

Flat parts tend to stick together in the tumbler.

A bit of blasting media in the tumbler, with water, stops this from happening, and speeds up the process greatly.

I never used to have a problem, except cleaning out the damned tank all the time.

It was a big PITA.

Heavy, awkward, cumbersome.

So, I ran a hose to the bottom drain hole, and just loop it around something higher than the bowl in the shop.

When cleaning time comes, I drop the hose out the door, and dump a couple of buckets of water in the tank to clean it out.

Works great, I love it.

However, when those days come that I need to tumble a bunch of flat parts, and I use grit, I discovered a problem.

The grit all migrates down to the bottom of the tube, and falls out of the solution.

Parts stick together.

Even worse, the grit seems to form a plug in the tube that is really difficult to clear.

If I am in the shop, it's not a huge deal, every 15 minutes or so, I go blow through the tube, and unstick whatever parts are stuck.

I need a solution that doesn't rely on me to work well...

So, a timer, hooked to a pneumatic solenoid.

Every 10 minutes or so, I want it to energize the valve for a few seconds, and release air through that tube, pushing the media that has fallen out of solution back into the tank.
 
Sounds like a Stamp is too sophisticated a solution for this problem, IMO.
How about a ball valve between the tumbler bowl and the hose, that might be the ticket.
CW
 
Got the parts today.

Took me a while to sort out how the timer worked, as I was expecting it to pass the input power to the switch legs.
It doesn't, it's just a switch.
I had to supply power to the valve, as well as the timer.
Of course it's the same power line, with jumpers, unless that's bad.

It works too well at the moment,as it spits out way too much air.
I tried a Harbor freight regulator that I have lying around, but it's junk.
Pressure builds up while the switch is off, so the system gets a powerful shot of air before slowing down, shooting sludge and media all over the place!

I found a flow control valve I had lying around, but it's a push on tubing type, so I gotta make a run to Ace Hardware in the morning to look for a couple of adapters to work it into the system.

Once I do that, and bolt everything down to something, I should be golden.
I want just enough air flow to clear the hose, not blast stuff everywhere.

I'll post a pic.
 
If you're already running this with reduced pressure -regulator

and maybe reduced volume from the needle valve,

why not just keep a steady burbling flow of air?

It should help with mixing & be easier to set-up.
 
On account of I'm a geek...

It's running like a top now.

In reality, I have a few things around that I want this, or similar circuits on.

I have been thinking about it for a while, and now seemed like a good time to get the ball rolling.

I really want a momentary circuit for a misting unit on my grinder, and now I can make one.

I'll post pics soon.
 
Pictures.

Overview.
Air comes in at the left, and out the right.
There's a quick disconnect so i can still drain the system.
I disconnect it, and drop it out the door into a drain next to the house.
IMG_0996.JPG


A better shot, showing the flow control on the left.
No need for a regulator, the flow control does what I need it to do.
IMG_0998.JPG


The tumbler...
IMG_0999.JPG
 
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