ass-pirator problems

[gruns]

I recently aquired one of those spiffy all-steel aspirators, very similar to this one:




I hooked this badboy up to the shower pipe, put a tube on the inlet port, made sure everything had teflon and hose clamps everywhere, I turn the faucet on and put the end of the tube in my mouth (new tubing) to verify the vacuum... and... nothing.  My water pressure isn't spectacular, but it certainly isn't drooling out of the pipe either.  Is my aspirator fucked, or am I not doing this right, or do aspirators require really great water pressure to work at all?

Heheh.. the aspirator I built out of PVC fittings worked better off the bat... :p

[homeslice]

Your going to waste a lot of water using a shower head. I'd use a recirculating water pump 3/4 hp if it was my dream. But that wouldn't be my dream b/c id fork out the extra hundred bucks and buy a nice ritchie yellow jacket pump which is much more worth it  

I had an aspirator first, before my ritchie, and personally i thought it was fuckin beat. I was spending more money on ice to keep the water cool that was recirculating with my pump than i paid for the fucking pump. Fuck that shit, get a ritchie  

[spectralmagic]

Tap water is icy cold and was until recently free in my neck of the woods, so an aspirator working right off the shower worked well.  SWISM's was all-glass, rather different-looking than in the picture, and pulled MDP2P at around 166 C even with restricted water flow (to save water he'd ramp it up to full vacuum, then back off the water flow until it was just above the point that it wanted to suck water back into the system - oh, and don't flush the toilet while doing this!).

Going to have to look into this Yellow Jacket thing whenever SWISM gets off hiatus, sounds good...

[ragnaroekk]

require different amounts of waterflow and waterpressure. Bigger is by no way better here - small aspirators work usually best, those from glass not bigger than a mans hand (without outlet tube) brought me the best results.

[gruns]

I've got a .5hp alcatel pump, but I haven't gotten around to aquiring either pump oil or the NW fittings it requires, not to mention a vapor trap and a vacuum gauge.
Those little bastards are expensive!

Besides, all I want this for is vacuum filtering.  I'm thinking I should have sprung for that plastic hand-vacuum I keep seeing in catalogs... :p.

Thanks for the tips.

[edit]

I just took the ball-bearing backflow apparatus out of the inlet tube and hooked it up... water began pouring from the inlet tube as soon as I turned the water on.  Also, when I tested previously I tried blowing into the inlet tube to no avail.  Argh!

[homeslice]

Water in my area isn't free. Actually its really fuckin expensive. Right now w/o having a shower running all day long some days, its like 80 dollars a month. So swim had to go and look into a recirculating one and the pump heats the water fast. I mean the bucket would dissolve a bag of ice in like 30 minutes.

[chilly_willy]

I am guessing your aspirator works fine.  Take it to someones house with really good water pressure and test it on their sink..then try the vac output.  BTW- I tried making one of those aspirator stations a couple weeks ago.. (jet pump, bucket, & pvc. This is absolutely necessary with bad water pressure..) You have to be real careful though with the power of those jet pumps.  I used a 1 hp jet pump with like 1&1/2" tubing on the intake & exhaust with a side drain tube next to the aspirator to reduce the back pressure. It wasnt enough! When I turned it on the aspirator shot like a firehose and after like a minute my pump exploded from 360 deg. and sprayed me with water.  Save yourself some trouble and get a fridge pump.  Since my last writeup on this subject I discovered a few tips to improve performance.  If you dont seal the other lines coming off the pump..you can recirculate chilled air thru the pump keeping it within an acceptable working temp and greatly increasing its life span.  Also sucking in clean vacuum pump oil into the vacuum line and letting it spit out the dirty oil through the compressor line really improves the vacuum performance and cleans out some of the condensed solvents, etc. that accumulate after time. If you want awesome, super reliable vacuum get yourself one of those small (1/5-1/8 hp HVAC vacuum pumps) they are really small, quiet and will easily pull 29" vacuum. ebay has em for around $85.

CW

[Bond_DoubleBond]

nothing beats the ease of use and monster sucking power of a ritchie yellow jacket.

it's a bee's best friend  

[pyroflatus]

gruns, if water comes from the sidearm of your aspirator with the backflow valve removed, there may be some teflon tape or some other physical obstruction in the aspirator jet. The aspirator relies on a reasonably uniform jet of water being shot past the sidearm aperture in order to create the low pressure zone, and if a piece of taflon tape or other solid crud gets caught in the aperture, the water jet is generally no longer uniform and will often squirt water out of the sidearm.

You may wish to remove the aspirator and fish out any solid gunk with a pair of tweezers, or flush the thing out backwards with water to clear the jet. Alternately you could dismantle the aspirator for inspection, and check that the jet nozzle is in good shape.

Don't mind me; I think it is amusing to watch an aspirator drink a glass of milk.

[Glasya]

Looks like SWIM bought the same aspirator and there was a burr down the inside of the aspirator, SWIM ended up taking it apart and re-reaming the main line for the aspirator and everything worked fine after that, SWIM is using a 1/2 pump and gets ~28" through it now.

[ragnaroekk]

I found very good information (and some nonsense   ) here:

http://www.sciencemadness.org/talk/viewthread.php?tid=437

For those who think on building one by them own and just to get a clue how these things may look like....

RaG

[Mr_Bronson]

There's some good information on that link, especially from Organikum. I, however, would not attempt to construct the water-jet pump itself (aspirator) unless I was really desparate. It would take a lot of trial and error to get the jet dimensions and chamber dimension just right. Water-jet pumps are cheap. The trick with building a recirculating water-jet pump is to get a water pump of just the right size: most are too big and heat the water excessively. 100 W (1/7 horsepower) is more than enough for most water-jet pumps. The trouble is that most cheap water pumps are either overpowered garden pumps or underpowered aquarium pumps: getting something that will pump 15 L/min (3 gallons/min) at 1.5 bar (and no more) is not easy.


Charles