I thought I'd ask about this. Is it possible to use a conventional
cylinder vacuum cleaner (old sausage dog type) to pump clean water?
These cleaners work by passing the filterd air stream through the
motor to cool it, so the water would go thru motor as well.
For any unaware person reading this, don't do it as its clearly
dangerous, my question is whether its _possible_?
Regards, NT :)
I'd have to say no.
At least certainly no unaltered.
The rotor spins at some tens of thousands of RPM.
Even if it could keep this speed when water got to it, it'd be destroyed
by cavitation and general stress, as it's so lightly built.
Run at a few percent power, I think you would get some pumping action.
If pumping very clean/distilled water, the corrosion may not be that bad,
and you may get a reasonable life (few days of pumping continuously) as
contaminants will get washed away from the brushes rather than conducting
Losses from "windage" due to the close gaps in the motor will be large.
http://inquisitor.i.am/ | mailto: firstname.lastname@example.org | Ian Stirling.
I have used one to pump air out of a barrel. Another pipe from the barrel
can be used to suck up water. You have to make sure that water level never
reaches the air pipe, and you can only run it briefly as there isn't enough
air going through the motor to cool it.
Interestingly, a choked off vacum cleaner draws much less power than a free
running one ! If you block the pipe, you will hear that the motor runs
*faster* - showing that the load is less.
This is due to the characteristics of centrifugal pumps - you can look it up
in an engineering encyclopedia or handbook - or I'll bet there is info on
Possibly, the choked off cleaner may overheat because the motor still
consumes power and has almost zero airflow.
At work we have a solder fume extractor rigged up from a barrel vac hooked
up to a solder iron tip extractor. Very little air flows into the cleaner
through the small diameter tip pipe, yet the cleaner runs for minutes and
has never failed.
Definite no-no !
Water and air have vastly different viscocity.
Quite apart from the scary water/electricity aspects.
What about a Vax type wet/dry vacuum where
the water doesn't come in contact with the motor?
When the water container gets full you could automatically
empty it with a pressure switch/ electrical solenoid.
There is also a simpler way to do auto emptying using the
weight of water to trip a counterweighted flap.
Lets look at it this way. Water is more viscous, so as water flows
thru it would presumably slow it down and work, at least in that
Power consumption would go up from motor loading, but then water
cooling would deal with that too, maybe.
Of course there might be a fair bit of power flowing thru the water,
so maybe it'd be warm water coming out the back.
Right. I guess losses aren't too big a concern in something as barmy
as this :)
You sure? Want me to try it and see? I'll bet you're wrong ;)
actually that's not hard to deal with. earth the case and you have an
earthed electrode heater.
PS dont try this at home
And trip the RCD which stops the pump.
OK you could use an isolating transformer to stop that, (with extreme care)
but when the seal between the motor and pump vanes leak (they are not
designed for water)
you get water in the motor electrics, electrolysis, and corrosion will
eventually stop the motor
if the huge increase in power caused by the presumably low conductivity tap
or worse still dirty water doesn't.
It could last a few minutes if you bypass the RCD. (MTBF 0.1 hrs my
Much better to try the wet/dry Vax type with auto empty.
I don't know how effective it might be, but you might
consider using the exhaust airflow to suck up the water.
-->Airflow--> --> Air+Water -->
I'll think I'll patent that, call it a carburettor maybe.
Tony Williams. Change "nospam" to "ledelec" to email.
How about: /\ Vacuum
-->Airflow--> --> Air+Water |
-----------------/ /----------------| |
/ / _| |_
/ / | | |
/ / | \/ | Water
/ / |~~~~~|
/ / |_____|
Would that work, or would all the water still end up in the vac?
Older friends will remember the Flit flykiller sprays that worked
just like this - far more ecological (from a material pov only) than
aerosol cans. For a picture see
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm
I have to admit that I'm an older reader and whilst I never saw one of those
pump-type sprays in the flesh (well, metal: you know what I mean) we did
have an attachment for our old Electrolux sausage type vacuum cleaner for
spraying stuff (never sure what stuff: we had the gizmo but I never saw the
instructions or any description for it). It consisted of a glass jar with a
screw-on lid: the lid incorporated a telescopic tube which dipped into the
jar, a socket for the vac hose and a nozzle out of which should emerge what
was being sprayed. The idea was to attach the hose to the blow (exhaust) end
of the vac so the flow of air through the gizmo would create a suction and
draw up liquid from the bottle and spray it out as an aerosol.
Never worked, mind.
I remember my Dad in the 1960s spraypainting with one of those vacum cleaner
attachments. It really did work for him. You put your finger over an air
hole to start spraying. I wonder if its still in the garage at Mum's place
Some 15 years ago, in Tunesia, I saw a butcher using it on the
cadavers hanging outside his shop, against the wall in the bright sun.
The sheepheads where in carton boxes, and bargained as 3 for the price
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