Hello
I have a crane with large cylinders (rod side volume 160 L or 42 gallons), running A11 260 pumps with LS. What I've noticed is that the response when lowering the boom is slightly slower (a few tenth of a second) than when raising the boom.
Here is what I think:
When raising the boom there is a limited amount of oil between the valve and the CB valves on the cylinders that needs to be pressurized before the boom will lift.
However, when lowering there is a large volume on the rod side (assuming the cylinder is halfway retracted or so) that also needs to be compressed before movement starts.
I believe the initial pressure buildup of the pump is critical, once the pressure is up to 50 or 100 bar it will respond much faster than it will at 25 bar (which is the standby pressure).
So based on this I'm considering putting a 50 or 100 bar sequence valve close to the directional valve's B-port (rod side). That would give the pump instant resistance and pressure would build much faster. The extra heat generated is not an issue at all here.
Any inputs? I know I've left out a ton of details but the key question is really if the difference in non pressurized volume makes a difference in the response of an LS pump. And yes, response is an issue here.
I have a crane with large cylinders (rod side volume 160 L or 42 gallons), running A11 260 pumps with LS. What I've noticed is that the response when lowering the boom is slightly slower (a few tenth of a second) than when raising the boom.
Here is what I think:
When raising the boom there is a limited amount of oil between the valve and the CB valves on the cylinders that needs to be pressurized before the boom will lift.
However, when lowering there is a large volume on the rod side (assuming the cylinder is halfway retracted or so) that also needs to be compressed before movement starts.
I believe the initial pressure buildup of the pump is critical, once the pressure is up to 50 or 100 bar it will respond much faster than it will at 25 bar (which is the standby pressure).
So based on this I'm considering putting a 50 or 100 bar sequence valve close to the directional valve's B-port (rod side). That would give the pump instant resistance and pressure would build much faster. The extra heat generated is not an issue at all here.
Any inputs? I know I've left out a ton of details but the key question is really if the difference in non pressurized volume makes a difference in the response of an LS pump. And yes, response is an issue here.
