A-VRFC3C-VEI-VS

Description

The flow control valves series “A-VRFC3C-VEI-VS” are 3 way, with one inlet “P” and two outlets “A” and “B”, the first outlet “A” being priority, pressure compensated type, with pressure relief valve and available on demand through a solenoid cartridge; the second outlet “B” is the by-pass for all flow in excess of what demanded by priority. Both flows from “A” and “B” ports can be employed to power different functions of the machine. These valves provide a simple and efficient way to power hydraulic tools (such as hydraulic hammers) from the existing hydraulic system, without any need to modify the directional control valve. They allow the simultaneous operations, independently from the respective working pressures, of both the hydraulic actuator powered by the priority outlet “A”, and of the normal functions of the machine (traction, slewing, cylinder motions, etc.) supplied by the main directional valve through the by-pass outlet “B”.

When positioning and tightening the valve, avoid any deflection of the body which could prevent the internal spool from sliding freely and impair the metering performance; it is recommended to use the 3 available fixation holes as locating points and to fit 3 equal spacers (metal washers), one on each point, between the valve body and the supporting structure.

Connections to the hydraulic system:

• Port “P” (inlet) to the main line from the pump.
• Port “A” (priority outlet) to the line feeding the hydraulic hammer, or the attachment. Important: for the correct metering of the compensating spool the priority outlet shall be always pressurized, with a back-pressure of at least 8-9 bar (115-130 psi); if necessary, fit a check valve with the needed cracking pressure.
• Port “B” (by-pass, or excess flow outlet) to the line delivering the oil to the main directional valve.
• Port “T” to a tank line. It is absolutely necessary that port “T” is connected to a low pressure tank line, 1-1.5 bar max (15-22 psi max).

The volume of priority flow from port “A” can be easily modified by turning the screw (1): the flow increases by turning the screw clockwise and, once adjusted to the desired level, it remains constant independently from the working pressure.

The maximum pressure in the priority line “A” can be adjusted by turning the screw (5) of the small relief cartridge (6) which controls the maximum pressure in the chamber (3): when this “pilot” cartridge opens, the pressure in chamber (3) drops and the priority flow is stopped.

Note: the relief cartridge (6) controls only the maximum pressure in the priority outlet “A”, and does not control the pressure in the by-pass and main line: the main line must be protected by another relief valve, capable to discharge the full oil flow.