Hi all We're setting up a rotating grapple saw attachment on a Volvo EC220DL with X3 hydraulics - and needed a solution for running the saw function. Grapple open/close is running off the computer adjustable X1 circuit whilst rotation is connected to the X3. Rather than fitting another valve from the valve bank to run the saw, a priority flow regulator valve has been installed directly between the pumps and valve bank; in the same way as some mulcher attachments are set up. When activated the saw is prioritised with the excess available for all other machine functions. Otherwise the saw is dead and all oil flow is available to the valve bank for other functions to operate normally. The saw function operates from a spare joystick trigger button with power taken from the existing harness and wired with relay back to the priority valve, separate to the machine computer etc. Here comes the challenging part...(for us at least) We need to connect to the Volvo load sense in order to stroke the pumps, however this is all electronic in the EC220DL. Right now we don't have the below-pictured LS line or shuttle valve installed as we don't have the right info from Volvo when it comes to the correct electric/hydraulic LS connections on the excavator... At one point we thought we could use another function (grapple close for example) to stroke the pumps, and then simultaneously activate the saw control but due to the low flow demand on the grapple circuit only one pump is coming online with this technique. Does anyone have any experience or suggestions regarding the fitment of priority valves similar to this and getting both pumps in a two pump system to stroke for the function via LS or otherwise? Cheers
Are you using your bucket cylinder in this configuration? If not I would use that to run the grapple and just run the saw with X1. If there is no way of getting around using the priority valve it will need some way to activate the pumps through the ECU. You will probably have to have your dealer change some parameters to optimize the control. Your supplier of the priority valve should be able to help you come up with a signal to interface with the excavator. The machine is positive control and there is no good way of activating it using negative control. These machines are not LS control.
Ben is absolutely on point. That said, why would you need both pumps for a low flow function.
Thanks guys, the bucket cylinder is already being used to manoeuvre the grapple connected via quick coupler. The grapple cylinders operate from the X1 circuit which is a relatively low flow function, but the additional saw circuit isn't this low; at around 170L/min. I wasnt sure if perhaps someone had run across the same challenge before and had some suggestions. We're waiting for advice from Europe but unfortunately most of the right guys are on their summer vacations....!
Why not run a high flow A/B valve off X1. You could have a simple dual circuit install off one valve spool. Plus , with X1 you could set up for 2 pump flow if not already equipped. Is the saw motor going to require a case drain line as well?
This machine was set up to articulate off x3, close and open with x1 and tilt off bucket. I see no reason you couldn't "tap the x1 circuitry with a valve at the stick connection block.
The priority valve, control wiring and plumbing is already fitted, so we're really chasing the possibilities for the final piece to this setup puzzle - although ideas for future installations are also appreciated! We have grapple open/close off X1, rotate left/right with X3 and tilt off bucket. Saw needs to be operated independently and if necessary simultaneously to other controls, without any 'switching over' from the operator. Edit: a case drain line has already been installed from the saw motor (through the rotator swivel port)
1)You have to excite a spool to gain oil flow , as said earlier i would look at X1 since you have the capability of 2 pump flow. 2) You have to divert that oil flow through some input from the operator. Either an unused function in the left hand joystick or an additional switch/button. I don't see another way to get you the flow you need.
X1 is capable of far more than you require for that saw. It probably would have been easier to install a solenoid actuated valve bank on the saw and just run X1 as a supply for all functions. The manufacturer of your priority valve should be the one working with your dealer to facilitate this installation. Most likely you will have to induce a signal through some of the servo pressure sensors to stroke the pumps. Support from Excavators will come from Korea not Sweden. But they are on holiday as well.