Need some help with a math question
Need some help with a math question
(OP)
I swear I've lost my marbles... they are somewhere around here.
A cylinder has a PO operated check on both rod and blind ends. The ratio of these checks is unknown. The cylinder is extending and lifting a load of 10,000lbs. The dimensions of the cylinder are 5 x 1 x 30. The cylinder is stopped mid stroke and both checks close. The cylinder develops a leak across the piston seal. What would the pressure gauges at the blind port and rod port read once the cylinder stops moving.
I know the gauges will equal out, and cylinder drift will stop before bottoming (if there is enough fluid to lock it). I know it takes about 510 psi to raise the load. Why is 510psi not the correct answer, and how do you find the correct answer?
Thanks;
Chris
A cylinder has a PO operated check on both rod and blind ends. The ratio of these checks is unknown. The cylinder is extending and lifting a load of 10,000lbs. The dimensions of the cylinder are 5 x 1 x 30. The cylinder is stopped mid stroke and both checks close. The cylinder develops a leak across the piston seal. What would the pressure gauges at the blind port and rod port read once the cylinder stops moving.
I know the gauges will equal out, and cylinder drift will stop before bottoming (if there is enough fluid to lock it). I know it takes about 510 psi to raise the load. Why is 510psi not the correct answer, and how do you find the correct answer?
Thanks;
Chris





RE: Need some help with a math question
The forces must equalize for the cylinder to halt retraction.
444482.2N force
3.517MPa to hold
Leak in piston seal - Pressure must equalize on both sides now
Presuming 35.17bar in FA when po checks seat.
Pressure in AA unknown presuming 0
Cylinder Area ratio = 1.04:1
Presuming no leaks and fluid incompressible
AA new pressure due to leak = 3.517MPa
AA new force due to leak = 87252.3792N
FA new pressure due to leak = 6.88MPa
FA new force is surprisingly enough = 87252.3792N
At this point the cylinder is hydraulically locked. But can be displaced back and forward within the volume limits.
I think that's right. But do shoot me down in flames if it's wrong.
RE: Need some help with a math question
Correct?
RE: Need some help with a math question
Yes that's correct.
RE: Need some help with a math question
Ted