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  1. #1
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    Default Who remembers enough math

    Who remembers enough math to tell me where to measure and how to figure the amount of oil per revolution.

    Dusty

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    With all those odd shapes I think you'ld have to do a physical test to get your answer.

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    didn't learn enough in math to calculate that, but learned how to find stuff:

    "The methodology for developing the mathematical expressions for determination of gerotor pump theoretical flow is presented in this paper.
    The theoretical flow is equal to current alteration of volume at working chambers that are linked with output side of the pump.
    For the calculation of the working chamber volume at gerotor pump the method that consider the influence of infinity small rotation angles of pump's working elements to elementary changing of volume are used and determination of working volume of chamber is done after integration.
    The developed analytical model is illustrated by numerical examples in which the influences of design parameters to variations of gerotor pump flow are analysed.
    The pump with fixed axes of shafts is considered in this paper but developed expressions by establishing specific kinematic relations can be, also, used at pumps with planetary motions..."

    https://www.researchgate.net/publica...EORETICAL_FLOW

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    If I had to guess, and it would be a guess, I'd say it will probably displace the volume of one of those chambers with the rotor bottomed.

    There's also clearance/slop.

    What are you doing?

    I know that, under the right circumstances, a pump like that can build enough pressure to break a steel transmission drum if it gets out of control. Does that answer your question?

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    “Per revolution”, it will displace the volume of the shaded lobe area X10. The best you can do in calculations is to approximate the volume of the lobe area, at its max opening, just before compeession begins. This will get you close. I think.

    Click image for larger version. 

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    Last edited by rockman96; 11-28-2020 at 8:59 AM.

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    I'm trying to figure out how much to grind off the width to make it put out the same volume as the piston pump it is replacing. The piston pump completes a stroke every 9 revolutions causing alternate skating and starvation in severe service. It's sized for a relief valve system and I will have to reduce the volume to run in a unrestricted system. It seemed like there was a formula for approximating the displacement.
    Dusty

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    I think you're gonna need a PR valve of some sort. Even a spring and ball would be better than nothing at all.


    I've seen equipment hydraulics wits similar systems and it is cool because you can then tune the pressure with a gauge and a washer stack on the PR valve spring.

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    Quote Originally Posted by confab View Post
    I think you're gonna need a PR valve of some sort. Even a spring and ball would be better than nothing at all.


    I've seen equipment hydraulics wits similar systems and it is cool because you can then tune the pressure with a gauge and a washer stack on the PR valve spring.
    This.

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    what about using plasticine

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    I would think the volume per revolution would be the volume within the outer gearotor minus the volume of the inner rotor. I should think that you could CC it and find the answer empirically.

    Jim

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