Measuring a hydraulic pump

[J. Schwiebert]

O. K. When I taught hydraulics for Dana we had a formula that you could use to determine the output of a hydraulic pump. I have not done that for 14 years and now I can not find it. This is for a gear pump and I think there is more than one formula. Thanks in advance. J

 

[DLMKA]

hydraulic pumps are usually sized in cc/rev.

If you want gpm take your pump size in cc/rev * pump speed (rev/min)*0.0002642

This will give you theoretical pump flow, if you want to get closer to actual pump flow multiply that number by 0.85 (85%) to account for pump slip, not a prefect number but close enough, need actual pump maps to get much better.

 

[mmidlam]

There was a formula where you measure the diameter and width of the gears. It was in this booklet I had.
fluid power handbook

 

[cwtech]

Here are two online calculators to give your output.

http://www.intlfpa.com/content_cal_gpmcalc.html

http://www.metaris.com/displacement-calculator.php

The paged linked here also shows the formula.
Formula & calculator for gear pumps

 

[J. Schwiebert]

Thanks guys. The formula I was looking for was posted by cwtech. For mmiplan I used to pass those books out in my classes, for DLMKA we used to do that with used pump and we would use the formula as there are a little manufactures that are not in business anymore so you find a replacement pump.