LVS—Post Compensated Valves for Track Drive Systems
When using a post compensated valve in an open loop traction circuit, where the left and right side drive motors are connected to individual spools, the pair of spools acts like a flow divider valve whose ratio is dependent on the relative spool displacements. If both spools are displaced equally, the pair acts like a typical 50:50 flow divider.
This has the advantage of having positive tractive effort control, even while turning the machine, with one spool displaced at less flow than the other.
Since the two spools are flow sharing, even if the operator displaces one valve fully and destrokes one valve hoping to turn, and if the total spool demand exceeds supply, the unit will still have traction control even if the wheels or tracks of one side begin to slip.
This also allows us to slightly oversize the spools for lower pressure drop in the drive circuit. If the same thing was done with a flow divider, accuracy of division would suffer.
Our LVS two spool post compensated valve combined with a pump compensator circuit can be very efficient in open loop drive applications. Certainly not as efficient as a closed loop hydrostatic system, but not all machines require that complexity.