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I found a Venturi Vacuum Generator on the cheap
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Author:  Mike Kroening [ Wed Apr 22, 2009 4:27 pm ]
Post subject:  I found a Venturi Vacuum Generator on the cheap
Hi all,

In my quest for a larger vacuum bagging clamp system I have been looking all over for a venturi vacuum generator for a reasonable price. Most seem to start at 40+ $ well I have found one for about $15. :)
Yep, Harbor Freight has an air vacuum pump on sale for $12.99. I added a few fittings for about $2.25. Well It pulls 26.2 " of vacuum @ 90 psi using 4.2 cfm Not bad for on the cheap. Now I need some caps for the 3" PVC res tanks and I'll have a new vacuum bag clamp system. I know there will be some other fittings as well needed but most are minor in costs. Hope this helps someone like me, that's on a fixed budget.

BTW I painted the venturi block :)

Mike


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Author:  Mike Kroening [ Thu Apr 23, 2009 2:24 pm ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
An update to this, if anyone is interested?

I chose to use a 5gal air tank from HF instead of the PVC route. For the same price as four 4" pvc caps, @7.95ea, I bought the tank. I added a few valves and a new Vac gauge, my other gauge is 30+ years old.

As you can see a very basic system but was able to pull 29" vacuum in less than 2mins on the tank. I think that's exceptable? Total parts are still under $100.00. That's excluding hose and bag.

Thanks for looking,
Mike

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Author:  ClintB [ Fri Apr 24, 2009 9:17 am ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
I'm interested, for one. Thanks for sharing this Mike. I have all the parts I need to put together a venturi system, except for the PVC. I was thinking of getting a portable tank from Princess Auto. I'll have to compare prices. I wouldn't have thought you could do the system for under $100. Good on you. Mine's already above that.
Author:  Mike Kroening [ Fri Apr 24, 2009 12:28 pm ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
ClintB wrote:
I'm interested, for one. Thanks for sharing this Mike. I have all the parts I need to put together a venturi system, except for the PVC. I was thinking of getting a portable tank from Princess Auto. I'll have to compare prices. I wouldn't have thought you could do the system for under $100. Good on you. Mine's already above that.
You are welcome Clint. Funny I found some coupons for this weekend that would allow me to lower the costs more at HF. go figure :) The air vacuum pump for $8.99 instead of $12.99 and a 20% off coupon for the airtank. Not much savings more but $10.00 is $10.00 that would pay for the gauge. LOL!

Mike
Author:  Michael Dale Payne [ Fri Apr 24, 2009 2:08 pm ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
Someone needs to understand a typical oiless 2hp 20 gallon compressor will not provide 4cmf @ 90psi so you will not get 22" of vacumm out of this venturi unless you have a compressor that can provid more than 4cmf @ 90psi that is going to put you in the 3hp range for an oilless unit and 2 hp rang on an oiled unit. Of course if you use a storage tank and a micro valve you are not running full time and you can get away with it but trying to use this to pull 22" of vacumm as a straight in line system is what I was speaking of.
Author:  Mike Kroening [ Fri Apr 24, 2009 2:31 pm ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
Michael Dale Payne wrote:
Someone needs to understand a typical oiless 2hp 20 gallon compressor will not provide 4cmf @ 90psi so you will not get 22" of vacumm out of this venturi unless you have a compressor that can provid more than 4cmf @ 90psi that is going to put you in the 3hp range for an oilless unit and 2 hp rang on an oiled unit. Of course if you use a storage tank and a micro valve you are not running full time and you can get away with it but trying to use this to pull 22" of vacumm as a straight in line system is what I was speaking of.


Michael you are correct. It does take a compressor that will supply 4cfm @90 psi constant if no shut off. My compressor is a dual tank 4 gal. 2 1/2 hp and I still have to allow for the compressor to catch up.

I just tested with a 36" x 54" bag and added a shutoff valve at the inlet (air Pressure side) as well. This allowed me to vacuum the tank, use it to vac the bag, Then shutoff between the venturi and inlet to allow the compressor to top off. By jockying the valves for a few minutes I was able to get 28" at the bag and hold it constant for over 1hr.

Thanks for bringing that up.


and now my total cost with bag and hose and extra valve has hit $197.98 tax included. Still not bad for a large veneer vacuum press.

MK
Author:  Michael Dale Payne [ Fri Apr 24, 2009 4:45 pm ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
Just to be clear I was not knocking the venturi but rather putting the warning out there that if ran as a straight inline vaumm supply, a typical 2 hp/ 20 gallon compressor would run full time and you would likely to slowly loose vacumm pressure as it did.
Author:  Mike Kroening [ Fri Apr 24, 2009 7:03 pm ]
Post subject:  Re: I found a Venturi Vacuum Generator on the cheap
Michael Dale Payne wrote:
Just to be clear I was not knocking the venturi but rather putting the warning out there that if ran as a straight inline vaumm supply, a typical 2 hp/ 20 gallon compressor would run full time and you would likely to slowly loose vacuum pressure as it did.
I understand and appreciate your candidness on this as I did not mention that fact myself. I guess It was my assumption that most would understand the reason for the resevoir tank, that it allows a lessor compressor to be used. :)

I'll post some pics of the chess board I just did using the new system. I worked flawlessly. :)

Mike
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