Sciencemadness Discussion Board

Water Pump Choice for Nalgene Aspirator

monstermandude - 18-2-2023 at 13:45

Hello everyone,
I recently purchased a Nalgene aspirator pump at a decent price and I've been looking for a water pump to go with it for a recirculating system. I was wondering what anyone here who has done this recommends as a water pump (brand). I'm finding it difficult to narrow down which pump to pick because of the mixed reviews on many.

Purpose is just for vacuum filtration but being able to use for vacuum distillation is an added bonus. I've been looking at ~6 Liters per minute pumps but knowing what others have chosen would definitely ease my conscience.

Sulaiman - 18-2-2023 at 23:59

I don't have aspirator experience but I just checked the specifications for a Thermo Fisher unit
6.5 l/min. @ 7.5 psig
So an 'ideal' pump would be 13 l/min, 15 psig
A little higher performance would be a good choice.

(small centrifugal water pumps are specified by
maximum flowrate with no back pressure, and
maximum pressure with no flowrate,
intermediate performance is slightly better than a straight line on a pressure vs flowrate graph)

monstermandude - 19-2-2023 at 03:39

Quote: Originally posted by Sulaiman  
I don't have aspirator experience but I just checked the specifications for a Thermo Fisher unit
6.5 l/min. @ 7.5 psig
So an 'ideal' pump would be 13 l/min, 15 psig
A little higher performance would be a good choice.

(small centrifugal water pumps are specified by
maximum flowrate with no back pressure, and
maximum pressure with no flowrate,
intermediate performance is slightly better than a straight line on a pressure vs flowrate graph)


I’ll have to try that. Out of curiosity for the future how did you figure out the lpm requirements for the pump(I understand the aspirator probably reduces the lpm and pressure but I haven’t taken physics in a long while)

B(a)P - 19-2-2023 at 18:08

Quote: Originally posted by monstermandude  
Quote: Originally posted by Sulaiman  
I don't have aspirator experience but I just checked the specifications for a Thermo Fisher unit
6.5 l/min. @ 7.5 psig
So an 'ideal' pump would be 13 l/min, 15 psig
A little higher performance would be a good choice.

(small centrifugal water pumps are specified by
maximum flowrate with no back pressure, and
maximum pressure with no flowrate,
intermediate performance is slightly better than a straight line on a pressure vs flowrate graph)


I’ll have to try that. Out of curiosity for the future how did you figure out the lpm requirements for the pump(I understand the aspirator probably reduces the lpm and pressure but I haven’t taken physics in a long while)


It is specified by the supplier.
https://www.thermofisher.com/order/catalog/product/6140-0010

monstermandude - 20-2-2023 at 08:47

Quote: Originally posted by B(a)P  
Quote: Originally posted by monstermandude  
Quote: Originally posted by Sulaiman  
I don't have aspirator experience but I just checked the specifications for a Thermo Fisher unit
6.5 l/min. @ 7.5 psig
So an 'ideal' pump would be 13 l/min, 15 psig
A little higher performance would be a good choice.

(small centrifugal water pumps are specified by
maximum flowrate with no back pressure, and
maximum pressure with no flowrate,
intermediate performance is slightly better than a straight line on a pressure vs flowrate graph)


I’ll have to try that. Out of curiosity for the future how did you figure out the lpm requirements for the pump(I understand the aspirator probably reduces the lpm and pressure but I haven’t taken physics in a long while)


It is specified by the supplier.
https://www.thermofisher.com/order/catalog/product/6140-0010


I think I just misread your sentence thinking you somehow figured out it would be 6.5 lpm once it reaches the vacuum pump and that’s why you need 13 lpm but you really meant that I should get 13lpm because a bit higher performance can be good.

Also I probably will do the 13 LPM if pump because they’re not that much more than the other Chinese pumps and they have better warranties.

[Edited on 20-2-2023 by monstermandude]

Mateo_swe - 20-2-2023 at 13:54

Water pumps for medium/large aquariums or small fountains usually work and are cheap.