If you are sufficiently far away from the pressurizing fan, there won't
be any perceptible wind at all. The fan will create pressure more than
flow. A conventional cleaning vacuum works by a difference in pressure
between the room and the catch chamber (the tank of a shop vac
perhaps). In the arrangement I'm considering, there still is the
difference in pressure, but this time it's between the room and the
I haven't done any of the math regarding how large the pressurizing fan
should be or what pressure should be achieved. But a rough estimate is
possible: To simplify the problem, let's say the house has no vents, no
plumbing fixtures, no gas appliances, and the house is of an almost
airtight modern construction. I often use a 6.5 amp (120 Volts) shop
vac and get respectable results. I imagine using an 11 amp fan (I have
one) as the pressuring means would get reasonable results at the
The next step in something like this is to experiment a bit.
Airline cabin pressure can go as low as 75% one atmosphere or
equivalant to an altitude of 8,000 feet.
The fact isn't relevant. I just found it while looking around and I
thought I'd share it:-)
Practical: No way
Implemented correctly you get:
Boy in a bubble, Clean room, Positive pressure
Don't forget, if you run this in winter you will throw away at least two
house fulls of heated air you paid for.
Cost effective: not a chance
I don't have a dog in this fight but my shop vac pulls about 40" of
water with a nrew bag. That is about 1/10 of an atmosphere or about
1.4 pounds. Not a lot of pressure but I bet it will blow the roof off.
What size motor does your shop vac have?
Considering the inevitable leaks, it would take an enormous compressing
fan to blow the roof off. (Your shop vac turned around wouldn't make
that pressure in a house.) I'm thinking of a fan something on the order
of 500 watts to 1KW. I'm not sure what pressure differential that would
create in a tight house, but I suspect it would be enough to do some
Interesting thought, but I'm afraid that pressure sufficient
to blow dirt out a discharge pipe would blow out the walls
or windows of a house.
Something I did that DOES work extremely well was to "pipe"
our house with compressed air. I had several quick connect
outlets across the house where we could plug in a 50' hose.
In addition, I had two 6" outlets that connected to my 5hp
shop dust collector in the basement. The vac wasn't one of
the portable types, but was a 5hp induction motor vacuum
that had two 6" inlets to collect sawdust and sanding dust
as I worked. By using a 6" flex hose from one of the two
outlets upstairs, it was like a "super" vacuum that moved a
LOT of air.
When it was time to do Spring cleaning, for instance, I'd
just lay the 6" lines into a room and use the compressed air
to blow dust off of our stone fireplace, Ficus tree,
bookshelves, library shelves, under beds, and even
baseboards. When followed by a good vacuuming of the carpet
by a conventional vacuum cleaner, we had great cleaning in a
Just how much dust and gas do you have in your house ?
I can't see going through all this trouble to remove dust from your house.
Unless you have have a 30 MPH wind blowing through the house, the dust is
going to settle on everything in the house, which will require dusting
You must be the only one who does, with the exception of course of those who
wish to rob you blind, and by that I mean those who will promise to
copyright it, market it and all the associated hangers on who want big fat
fees up front, they'll think it's fantastic and tell you that you'll make a
million from it, they are just interested in seperating you from your
My advice is ditch it, no one in their right mind would be interested in
having it in their home.
And one of the things they will claim is that it's a must for asthmatics,
it's not, if anything it will put more dust into a room than it will
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