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Old Jul 20, 2012, 10:32 PM
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Pasco Tri Cities, Washington, United States
Joined Aug 2004
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Source for a vacuum switch

Guys,
I'd like to add a vacuum-sensing switch that can turn the vacuum pump on and off at a selected vacuum level that I can set. I know many folks use such an approach, but don't know of a place I can buy one. ANy help will be appreciated.

Larry
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Old Jul 20, 2012, 10:52 PM
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Joined Nov 2004
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Quote:
Originally Posted by LRFitch View Post
Guys,
I'd like to add a vacuum-sensing switch that can turn the vacuum pump on and off at a selected vacuum level that I can set. I know many folks use such an approach, but don't know of a place I can buy one. ANy help will be appreciated.

Larry
I have used the one from www.joewoodworker.com and they work well

Only have 2 issues.
1 - Postage cost to Australia
2 - I have snapped the plastic thread over tightening.
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Old Jul 20, 2012, 10:55 PM
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United States, CA, Brentwood
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Mcmaster-carr
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Old Jul 20, 2012, 11:27 PM
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Joensuu, Finland
Joined Mar 2002
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Quote:
Originally Posted by LRFitch View Post
Guys,
I'd like to add a vacuum-sensing switch that can turn the vacuum pump on and off at a selected vacuum level that I can set. I know many folks use such an approach...
...and then there are those who don't like the pumping effect of fluctuating vacuum level and use a continuous run pump with adjustable bleeder valve. To each their own, both ways seem to produce acceptable parts.
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Old Jul 20, 2012, 11:37 PM
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United States, CA, Brentwood
Joined Jun 2012
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I have used a variable freq drive coupled to a vacuum transducer to eliminate the pulsing. It simply slows the pump down once the desired vacuum is met, and increases when needed. Probably not a hobby type solution as it was on a 3 phase LARGE industrial system and was not cheap to build.
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Old Jul 21, 2012, 10:46 AM
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United States, WA, North Bend
Joined Mar 2011
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Hi Larry - The joe woodworker switch works good for the price. Seems like the nicest nice setup is a an air tank for a reservoir with a switch to control the pump and a vacuum regulator on the inlet. Then you can pull a steady vacuum at the workpiece and have the pump cycle as little as possible. Mcmastercarr has a regulator for about $56 http://www.mcmaster.com/#vacuum-regulators/=ii4vp3 .
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Old Jul 21, 2012, 12:58 PM
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I just went thru this over the last few days. I bought a vacuum switch off ebay ( http://www.ebay.com/itm/250821538795 ), then built my system something like this: http://www.markrebuck.com/pics/uncla...vacswitch.jpeg

I'm using an old 5 gallon portable air compressor tank as my reservoir.

Not sure if I saved any money purchasing the switch off ebay, but I wanted to be able to control the hysteresis range, and the other switches I've seen (e.g. http://www.acpsales.com/VacuumSwitch.html or http://www.veneersupplies.com/produc...er-18-NPT.html ) tend to have a preset hysteresis range.
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Old Jul 21, 2012, 06:03 PM
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Pasco Tri Cities, Washington, United States
Joined Aug 2004
319 Posts
Thanks for the response

Guys,

Thanks for the ideas a links. Mark, I take it one of the contacts on the vacuum switch is N.O. and one N.C.? I had the same thoughts in mind, but was going to use a 120vac relay so I don't have to provide 12VDC from some source. Radio Shack has one that is rated for 10amps switched that should do the trick.
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Old Jul 21, 2012, 07:09 PM
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@LRFitch Easiest way to explain how the vacuum switch I bought works is to look at the datasheet from http://www.barksdale.com/en/products...1h-d2h-series/ . I bought a D2H-18SS. It is basically two independent SPDT switches in the same housing. It was important that I bought a switch with two set points so I could implement variable hysteresis. Internally, the vacuum switch is just a metal dome near two switches. The dome expands (pressure) or contracts (vacuum) to make/break contact with the switches. So the N.O and N.C contacts for each switch change if you are doing pressure instead of vacuum. It was easy to set every up given the documentation.

The relay I used was a 12V automotive relay that I had in my parts bin. My vacuum pump is a converted 12V electric bicycle pump (e.g. http://www.instructables.com/id/conv...ressor-into-a/ ) and I had a 12V supply from a converted PC power supply, so it all just worked out for me. I think any relay that works with your pump will do the trick though.

Not sure I saved any $ over buying a switch/relay from an online vacuum bagging supplier, but I had fun figuring out how to wire my circuit to do what I wanted.
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Old Jul 22, 2012, 08:49 AM
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Pasco Tri Cities, Washington, United States
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Thanks Again Mark

Mark,

The 12V relay makes perfect sense with a 12V pump. I think I'm now on the right track. Thanks for the help.

Larry
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Old Jul 22, 2012, 12:54 PM
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Joined Apr 2004
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Here's a vacuum regulator I got from Boeing's surplus outlet when they were still open. It regulates vacuum pressure without bleed. The pump/reservoir simply turns on and off between an adjusted pump vacuum of 23" to 26" Hg. Vacuum can be precisely regulated from 0 - up to 30" Hg.
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Old Jul 22, 2012, 03:50 PM
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Joined Feb 2006
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I burned one out because I was using line voltage without a relay. I needed it NOW so I bought a distributor vacuum actuator and built my own. It has worked fine for the last few years.

Tom
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Old Jul 22, 2012, 07:05 PM
Peewee Paraparaumu New Zealand
New Zealand
Joined Sep 2004
105 Posts
vacuum switch

http://www.poweraire.com/vacuum-swit...6_234_303.html




This is the one I have used.

best Peewee
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Old Jul 22, 2012, 09:14 PM
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United States, CA, Hayward
Joined Jul 2008
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ACP (Advanced Composite Products) has one.

$41

About half way down the page:

http://www.acpsales.com/Vacuum-Bagging-Fittings.html

I don't know if it's a good price or not. It seems kind of high, but perhaps that's just what they cost. I've generally been happy dealing with ACP, but this is not something I've comparison shopped.


--Soren

Quote:
Originally Posted by LRFitch View Post
Guys,
I'd like to add a vacuum-sensing switch that can turn the vacuum pump on and off at a selected vacuum level that I can set. I know many folks use such an approach, but don't know of a place I can buy one. ANy help will be appreciated.

Larry
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Old Jul 27, 2012, 11:42 AM
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United States, NC, Raleigh
Joined Jul 2011
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I too am using a D2H-18SS though I'm not sure why relay is needed? Maybe I'm not remembering my part # right, but it's rated at least 15A. I tried figuring out how to wire two switches to set high-low point but gave up. Instead my setup just uses two adjustable timers and a switch to select the side. The D2H-18SS has 5/16" hex adjusting nuts, so I mounted it at 45* and ran 5/16" drivers through my console. This lets me adjust the settings as needed. With the flick of a switch I can choose one of two pressure settings. It's worked out nicely so far. Care to share how you wired yours up so you can select hi/low points?
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