Patent ID: 6467501
Filing Date: 2002-10-22
Classification: G05D,Y10T

Abstract:
A constant fluid flow controller, comprising:a body with an internal chamber, an inlet opening for receiving fluid under pressure at P1 into said chamber, an outlet opening for discharging fluid from said chamber; valve means disposed in the body for passing fluid from the inlet opening to the outlet opening including; a valve cylinder disposed in said internal chamber, the valve cylinder having an impeller chamber having a first end and a second end, aligned along a bore axis; a piston movable in the impeller chamber along the bore axis; passage means in the body for fluidly connecting the inlet opening to the first end of the impeller chamber to fluidly bias the piston in a first axial direction; an orifice plug disposed in the second end of the valve cylinder, said orifice plug having an orifice opening for passing fluid therethrough from the inlet opening to the impeller chamber to fluidly bias the piston in the opposite axial direction; a spring disposed between the orifice plug and the piston in the impeller chamber to bias the piston in said opposite axial direction; a flow control port in the valve cylinder for passing fluid received through the orifice opening into the impeller chamber as pressure P2; a needle valve mounted on the body adjacent the orifice opening, the needle valve having an end movably disposed along said bore axis in the orifice opening for precisely adjusting the size of a fluid passage through the orifice opening and thereby the flow rate through the controller body; the piston being disposed between the inlet fluid pressure P1 and fluid pressure P2 either to open or to close the flow control port to maintain the fluid flow rate therethrough equal to a desired flow, in which P1=P2+ the bias of the spring on the piston, over a substantial range of inlet fluid pressures; and the orifice plug being threadably mounted in the valve cylinder to define a portion of the impeller chamber.