Sure. Use a piece of larger dia. pipe a a plenum. The two (or three) shop vacs will draw the pressure down in the plenum and you'll get the combined airflow (with some losses) to a single working port you could use as the source for your shop wide system. We used a similar concept in the Water Valley Holley Automotive plant (Now Bendix) to supply the vacuum flow for the mass flow testers throughout the plant.

GCG

 

Only issue I see with that idea is noise. You will definitely need hearing protection.

 

cool. i suppose i could make an enclosure that houses them with some insulation for sound deadening to help with the noise level.

 

That should do it!

 

Remember to allow for heat exchange/cooling for the vac motors, Chris; with two of them in a confined space there'll be substantial heat buildup. If you can salvage the heat, not a bad way to heat your shop!

 

Just put a vent low in one corner and an exhaust fan (computer box type) high in the opposite corner both insulated for sound and you'd be good to go.

GCG

 

Please don't tell me to go out and buy a "proper" dust collection system, because that is not going to happen.

Shop vacs are designed to move small volumes of air at high velocity at a high static pressure. Like those dopey vacuum cleaner infomercials where the guy picks up a bowling ball as the crowd Ohhhs and Ahhhs...Their impellers are far too small to be used in a "system". They work well connected to small tools, like a Fein or Festool vac connected to a sander or router. That's just the way it is. Connecting a 2-1/2" shop vac, or 2 or 3, to a 4"-6" pvc main, while producing a very large amount of noise, will result in far too low of a volume of air at the needed velocity to keep dust and wood chips suspended. That's just the physics of it. I wish the numbers worked for you, Chris, really, but I see you putting a lot of time and effort into this and not being happy with the result.
Good luck.

 

Avg CFM for a shop vac is around 150. Three would max out at 450 (volume is volume), less in real world conditions. Rockler's hang on the wall system is spec'd at 650 CFM (less real world) rated for 4" duct work. Chris, your idea would be a definite boost IMO and worthy of exploration. Some inexpensive PVC pipe and fittings from HD or Lowes would be all that would be need to prove it.

GCG

 

i could use a little extra heat out there in the winter months.

joe, i understand your points, and you could very well be right. but i think it can't hurt to give it a try. after all, i have more time than money these days. if i keep the receipts and just press fit the PVC pieces together, i can return the whole mess if it doesn't work out.

 

Hi Chris

I'm toying with the idea of a non-electrically powered dust collector. I reckon that if i can build a firebox to burn my waste that with a tall enough chimney I should be able to generate enough draught to extract a saw bench and heat a shop at the same time. What do you reckon? :jester:

Regards

Phil

 

Build up some creosote and start a chimney fire and it'll suck the fillings out of your teeth. That is till the shop burns down.

GCG

 

go for it phil! can you make a video of it too? i'm sure it will go viral!

do you already have a fireplace in your shop and enough waste to power it?

 

do you already have a fireplace in your shop and enough waste to power it?

Oh well, back to the drawing board

Regards

Phil

 

Hare brained is right! Lol

 

Really?


Really?

Central vacuum cleaner multiple vacuum source control - Cube Investments Limited

Title:

Central vacuum cleaner multiple vacuum source control


United States Patent Application 20070079466
Abstract:

A central vacuum cleaning system has multiple vacuum sources. The multiple vacuum sources are connected through pipes to wall valves. In use a hose is plugged into one of the valves. A handle is connected to the hose. A wand extends from the handle. Attachments such as a power brush are connected to the wand. Switches apply power from one or more power sources to the vacuum sources. The application of power by the switches is controlled by a control circuit.

Or Wikipedia:

Ultra-high vacuum - Wikipedia, the free encyclopedia

Achieving ultra-high vacuum

Extraordinary steps are required to reach UHV, including the following:
High pumping speed — possibly multiple vacuum pumps in series and/or parallel

 

Phil, I seem to recall seeing a photo of an Oneida Dust Deputy Cyclone unit that was connected to two shop-vacs. Now that I want to reference it, of course, I can't find it! So if someone is actually producing something like that commercially you shouldn't have much trouble creating one.

 

Hi Chris - I think you have a viable plan.... just don't connect the vacuums in series. I read a review once (amazon maybe) where some guy was one starring the dust deputy because it didn't work well with two vacuums. Reading through his review, I realized he had daisy chained the vacs.

 

john, if you mean that i shouldn't hook up the inlet of one to the outlet of the other, then no, i was definately not planning on doing that.

thanks

 

Chris, I found the two vacuum Dust Deputy page - The Multi Cyclone DIY Dust Deputy® Kit - http://www.oneida-air.com/inventoryD.asp?item_no=AXD990003&CatId={6EE79B16-EB63-43E7-8F30-1E06240A24A4}.

 

Sory this address dosn't work for me

Ray

 

Hey Chris. Have you given a thought to hooking your vac(s) into a chip catcher barrel/container, and then feeding the single pickup pipe out of that? Fiber barrels work great for that, and can be had cheaply. The vacuum pulls down the top so it doesn't even need clamps. And if you don't like the results you can always use the barrel for stock storage.

 

That sounds similar to the dust deputy setup. Not a bad idea, thanks.

Your problem is likely to be connectors. There are really no standards and I bet by the end of your project you will either not effectively collect dust (read inhale carcinogenic dust), or you will spend as much on parts and materials to have bought a high quality, powerful dust collection system. Also, to keep from having your vacs suck up chips and small chunks of wood (read jam vacs), you will need to get a drum, plus connectors to make a chip collector stage between the tool and vacuums. Ulead has 30 gallon, steel top drums for about $50. 4 inch pvc schedule 40 pipe is not standard sized for dust collection, so you will have to use adapters and lots of tape to make things fit. Schedule 20 pvc pipe is hard to find, but it fits better. If I had it to do over again, I'd sell the shop vacs and put my money into a commercial dust collection unit. Harbor Freight has an inexpensive one that is ugly, but workable. Jet, Delta and other companies make them, but they cost more. I'm a throat cancer survivor so I take dust collection very seriously. And, if you want to retain your hearing, I suggest you use both the insertable ear plugs and muff type suppressors. I hang them on a peg right next to the power switch to remind myself to use them.

Again, after putzing around building an effective dust collection system part by part, today I'd buy a manufactured unit big enough to suck a bowling ball through a garden hose. High CFM air flow is the thing you need.

Hope this helps.

Tom, the 2" PVC is a perfect fit for the 2 1/2" hoses of a shop vac. I use a Fernco and it is great.

I don't know about the 4" situation as I don't have a 4" vacuum, except for the leaf vacuum, and that fits a 4" Fernco and 4" pipe perfectly.

What size are standard 4" DC hookups? And don't most of the tools have 2 1/2" hookups anyway?

 

Your problem is likely to be connectors. There are really no standards and I bet by the end of your project you will either not effectively collect dust (read inhale carcinogenic dust), or you will spend as much on parts and materials to have bought a high quality, powerful dust collection system. Also, to keep from having your vacs suck up chips and small chunks of wood (read jam vacs), you will need to get a drum, plus connectors to make a chip collector stage between the tool and vacuums. Ulead has 30 gallon, steel top drums for about $50. 4 inch pvc schedule 40 pipe is not standard sized for dust collection, so you will have to use adapters and lots of tape to make things fit. Schedule 20 pvc pipe is hard to find, but it fits better. If I had it to do over again, I'd sell the shop vacs and put my money into a commercial dust collection unit. Harbor Freight has an inexpensive one that is ugly, but workable. Jet, Delta and other companies make them, but they cost more. I'm a throat cancer survivor so I take dust collection very seriously. And, if you want to retain your hearing, I suggest you use both the insertable ear plugs and muff type suppressors. I hang them on a peg right next to the power switch to remind myself to use them.

Again, after putzing around building an effective dust collection system part by part, today I'd buy a manufactured unit big enough to suck a bowling ball through a garden hose. High CFM air flow is the thing you need.

Hope this helps.

 

Hi chris why dont you try it out and if it works post it on this forum i do have a couple of wet dry vacs i think you gave me a idea in the summer months u can move them outside with a couple of feet of extra hoses and in the winter move them inside for heat just wear ear protection because the racket of two vacums would be unbearable nd good luck nothing tried nothing gained