info flow oil with choke

[s.melotto]

Hello everyone,
I apologize for ignorance... .
problem: I have a lifter with a simple effect cylinder (controlled by pedal pump), with out a stroking given by a grain with 0.8mm hole to drop weight slowly; the problem is that, without a proper precarious, the plan does not go down.
question: can it be that the hole is too small, and, due to the high viscosity of oil, this does not happen in the passage from 0.8mm? and if so, can you calculate the minimum hole to allow the passage of oil to a certain pressure?? or anyway, given pressure, diam of stroking and viscosity, how do I know how long it falls? ?

add info: the system, in addition to the stroking, has a maximum valve and non-return valves on the cylinder; the rest was obtained from the manufacturer on the body of the same. my big problem is that the design was made on "cheese card" and without keeping in mind; now I find myself not even knowing that alesaggio has the cylinder. I know only that, in order to adjust up and down, it is put hand to the valve that is defined "maximum" by those who mount it (but it's all to see), my colleague says to regulate it to set the maximum load liftable and that, if it increases too the reach, then the lift does not fall anymore (his weight is about 50kg), I must understand why.

Thank you for your kind availability
Good day to all

 

[meccanicamg]

a little difficult to understand if there is no plumbing scheme of how it is regulated.
if the return is handled as oil resurface in the hole from 0.8 just try to return a larger jet and see how it behaves.
logical blocks if they are regulated by system pressures to manage and or surely the more pressure rises and the more difficult it is to think that it returns alone.
you can calculate the scope and if you are looking on the forum we talked about calibrated orifice. However, it is a closed and unopened circuit and therefore the question is complicated.