Flow regulator

Claim 1

IN AN HYDRAULIC FLUID FLOW REGULATOR OF THE CONSTANT FLOW TYPE HAVING A BODY DEFINING AN INTERNAL FLUID PASSAGE EXTENDING BETWEEN SPACED INLET AND OUTLET OPENINGS IN THE BODY AND ADJUSTABLE VALVE MEANS WITHIN THE BODY REGULATING FLUID FLOW THERETHROUGH, THE COMBINATION COMPRISING: A HOLLOW PISTON MOVABLE WITHIN THE BODY AND OPERATIVELY CONNECTED TO THE VALVE MEANS; RESILIENT MEANS BIASING THE PISTON IN A DIRECTION TO ADJUST THE VALVE MEANS TO MAXIMUM FLUID FLOW; A RESTRICTED ORIFICE IN SAID PISTON CREATING A FLUID PRESSURE DIFFERENTIAL IN FLUID FLOWING IN ONE DIRECTION THROUGH THE ORIFICE AND THE PISTON, SAID PRESSURE DIFFERENTIAL EXERTING A FORCE ON THE PISTON TO MOVE IT IN OPPOSITION TO SAID RESILIENT MEANS AND IN A DIRECTION TO REDUCE FLUID FLOW PAST SAID VALVE MEANS; AND MEANS DEFINING A SECONDARY FLUID PATH BY-PASSING SAID ORIFICE, SAID LAST MENTIONED MEANS INCLUDING MEANS CREATING IN FLUID FLOWING OVER THE SECONDARY PATH A FLUID PRESSURE DIFFERENTIAL BETWEEN THE UPSTREAM END OF THE PATH AND A LOCATION ALONG THE PATH THAT IS A FUNCTION OF THE VISCOSITY OF THE FLUID AND PRODUCES A FORCE ACTING ON THE PISTON IN A DIRECTION TO MOVE IT IN OPPOSITION TO SAID RESILIENT MEANS AND IN A DIRECTION TO REDUCE FLUID FLOW PAST THE VALVE MEANS, WHEREBY THE TOTAL FORCE ON THE PISTON IS VARIED TO COMPENSATE FOR CHANGES IN FLUID VISCOSITY AND THE TOTAL FLOW THROUGH THE REGULATOR IS SUBSTANTIALLY CONSTANT OVER A WIDE TEMPERATURE RANGE.