Sciencemadness Discussion Board

Vacuum Aspirator pump pulling close to no vacuum

nolken - 20-1-2014 at 12:56

I just bought the Bel-Art 329470000. I have it hooked up to a standard US faucet and I am getting next to no vacuum. I hooked the gauge directly to the aspirator using a 60cm vacuum hose. The water output is placed directly into the drain using a 30cm PP hose. I have yet to measure a pressure of less than 680 mm Hg. At this point I'm assuming that the aspirator is faulty but I find that difficult to believe. Is it more likely that there is a fault in my system?

Here is the info sheet:
http://www.belart.com/shop/instruction-sheets/932947003.pdf

WGTR - 20-1-2014 at 13:31

What is the water output in gallons per minute (measure it)?

Second, when the vacuum is being measured, are there a bunch of air bubbles going out with the water stream? If so, there is
a leak somewhere.

[Edited on 1-20-2014 by WGTR]

nolken - 20-1-2014 at 13:53

2.89 GPM output without aspirator attached and 2.64 GPM output with the aspirator attached.

BromicAcid - 20-1-2014 at 14:02

So that's plenty of water according to the spec sheet. Can you have too much water? Never been in that boat but I don't think so. Next question, you're using cold water, right? Also restating WGTR's question, no air bubbles, right? If you plug both openings you don't get leaking where you're connected to the faucet do you?

nolken - 20-1-2014 at 14:02

The water exits with such a high velocity it was hard to tell so I placed the water output it in a class jar temporarily and I did not see any air bubbles. To confirm there are no leaks I placed my finger on the vacuum port and felt no vacuum. It does make a loud hissing sound leading me to believe the aspirator is taking in air but it may just be the water flowing through.

nolken - 20-1-2014 at 14:11

Correct, I am using cold water. There are air bubbles when the vacuum port is left open so it is for sure bringing air in. upon connecting the gauge the air bubbles stop even though the gauge is reading such a poor vacuum. I tried adjust the water flow but the change in vacuum pressure was very little. There is no leaking when I plug the water output. The vacuum port does have a check valve that seems to be functioning properly.

[Edited on 20-1-2014 by nolken]

Dr.Bob - 20-1-2014 at 18:38

Does the check valve rattle when you shake the aspirator? If it does not move freely, then it will often stick. Some of them unscrew so you can clean the ball inside.

WGTR - 21-1-2014 at 04:35

You did leave the little plastic tube on the output, right? I think that's necessary. Also, I think the water has to occupy the whole
tube on its way out, not just part of it. Other than that, I'm out of ideas.

[Edited on 1-21-2014 by WGTR]