Abstract: A hydraulic valve arrangement is provided for simultaneously opening or closing off the flow of fluid from a plurality of separate and distinct inlet fluid lines to a plurality of concentric fluid passageways connected to an internal mixing chamber having an outlet nozzle leading therefrom. The valve arrangement includes a spool valve axially slidable within a bore of a housing. This spool valve includes at least a central fluid passageway therethrough and another, concentric fluid passageway defined between the spool valve and the bore. When the spool valve is in the open position, the inlet fluid lines are in fluid communication with both the central passageway and the concentric passageway. Fluid flowing through these passageways enters into the interior mixing chamber and exits that chamber through the outlet nozzle. When the spool valve is in the closed position, flow from the inlet fluid lines to the passageways is cut off.