What vacuum pump is right for me?
What vacuum pump is right for me?
(OP)
I work in an undergraduate lab at a university and need to buy a new vacuum pump. We need to de-air 5 to 10 gallons of water for a TX and Permeability machines. My main concern is how low the ultimate pressure needs to be. Many suggested high vacuum pumps with ultimate pressures of 10^-4 torr, but this pump being in the $2000 dollar it is out of the range of price we would like. I have found cheaper pumps with max pressures around 21 torr, but is suggested for vacuum filtration. Does anyone have any suggestions on my situation?





RE: What vacuum pump is right for me?
Almost any vacuum pump can be used for de-airing water...the only difference is the time it takes to do it. I've used vacuum pumps for this purpose that cost less than $500 and they work fine. Also keep in mind that your container should allow a large exposed surface rather than deeper water.
If your vacuum pump is too powerful, you can collapse your container..
Assuming you are not at a high elevation, 21 torr should be a sufficient differential to "boil" your water.
RE: What vacuum pump is right for me?
RE: What vacuum pump is right for me?
RE: What vacuum pump is right for me?
Oldestguy, standard practice on triaxial and perm tests is to use deaired water.
RE: What vacuum pump is right for me?
This argument for triaxial test procedure can go on and on...as an example, why use backpressure saturation if your specimen is not saturated in-situ. Well...you get wonky pore pressures, but does it really replicate the in-situ condition?