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How to find a mathematical model of this hydraulic jack system?

I'm confused about the part when the piston extender, check valve 1 opens and check valve 2 closes, then liquid from the bottom tank flows into the tank that has the piston.


2 Answers 2


There are two pistons, which one are you referring to?

Downstroke of left piston will cause fluid to make right hand piston to rise by the volume of fluid displaced.

Upstroke of left piston will draw fluid through check valve 1 to fill left piston chamber.

Opening bleed valve will lower the right hand piston.

  • $\begingroup$ the left piston $\endgroup$
    – iklanpagi
    Commented Dec 6, 2021 at 10:19

$volume = \pi*r^2*height$

Fluid volume is the same in different pistons; height is the movement of the pistons.

Your height change of the pump piston is the distance moved by the ram = hand distance times that ratio of pivot to ram over total lever.

Pressure of the fluid is force applied (again, use the lever equation above in reverse) divided by the piston area ($\pi*r^2$).

  • $\begingroup$ thank you, and one more question for the right piston, is it use pascal law ? $\endgroup$
    – iklanpagi
    Commented Dec 6, 2021 at 20:11
  • $\begingroup$ @iklanpagi, yes, the pressure is the same throughout the system $\endgroup$
    – Tiger Guy
    Commented Dec 6, 2021 at 20:49

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