No, that's not correct. It may seem logical, but if you think about the pressure from gravity - it's only a couple psi. But the pressure from the pump is 2000-2500 psi. It way over powers any thing from the cylinder orientation.
jb
purging air from hydraulic lines
- Thread starter nicknewhall
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No, that's not correct. It may seem logical, but if you think about the pressure from gravity - it's only a couple psi. But the pressure from the pump is 2000-2500 psi. It way over powers any thing from the cylinder orientation.
jb
J_J
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After thinking on this for a while, air will go to the highest point, and if the outlet or inlet for the cylinder is lower, then you will have trapped air, and if pressurized, you will have maybe 2000 lbs of compressed air, and the cylinder will feel spongy. An analogy would be the the brake system on automobiles. Although the brake system is a one way line, the air will not back up through the system, and you have to let the air out. The release valve is at the top of the brake cylinder.
Soundguy
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I wonder how much of that air makes it past the packing...
soundguy
soundguy
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When you send fluid through a hose, it is travelling very fast. As soon as it enters a cylinder full of air, it shoots across it until it hits the other side and instantly aerates. Now you have a cylinder full of aerated fluid. Eventually, through working the cylinder, the fluid finds it's way back to the tank where it can get rid of the air. The longer the hoses, the longer it will take. Some air will make it past the seal as hydraulic seals, particularly the U or V shaped polyurethane styles, don't seal air very well. However, the aerated fluid won't go through the seal. The best way to get rid of air in the cylinder is just run the machine.
You know it's like I said, it ain't logical but it will fully purge. Just think about a loader lift cylinder. They are mounted pretty near vertical and the fill is on the down side so there is always the potential for a trapped air bubble, yet they get to be air free pretty quick, usually 3 or so full cycles up to down and there is no more air making it back to the tank and after topping off, the tank does not drop it's level. So either all cylinders in that orientation have trapped air or it gets out even if it logically shouldn't.
Some things I just accept...
jb