I'm looking at Marzocchi micro gear pumps, particularly the 2.00 model.

Speed range is 800-200 rpm (although page 20 shows flow for 100-3500), but in my application I plan on using a bi-directional speed controlled motor that may spend a lot of time between 800-0 rpm when changing directions (but also a lot of time in the advertised range).

The flow chart makes it look perfectly linear with a 0 gpm @ 0 rpm intercept, so I'm inclined to think it stays relatively linear between 800 and 0 (albeit no guarantees), so I'm wondering if it would really be that problematic.

My guess is the pump might need some minimum speed to properly self-lubricate, protect the bearings, etc. Maybe also to guarantee some pressure build up, which probably falls off pretty fast at slower speeds due to fluid having time to work its way through gear/wall clearance.

Any ideas what I might run into? The good news is this not for a customer, or production, but only a prototype so if the pump destroys itself that's fine so long as it's not immediately. Also, if you have better suggestions for pumps in this smaller size (little bigger wouldn't be bad, definitely sub 1 in^3/rev) or if I'd have better luck with another type (piston?) I'm all ears.

  • 1
    $\begingroup$ you mention rpm a lot, but what output do you need from the pump to consider it operational (pressure and flow rate)? $\endgroup$
    – Abel
    Apr 30, 2022 at 1:13
  • $\begingroup$ Using it for position control of a cylinder. Not a lot of force at the cylinder, haven't measured yet but I expect pressure not to go much above 30-40 bar. Flow rates will likely stay below 1 gpm. $\endgroup$
    – DrTarr
    Apr 30, 2022 at 11:12


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