Pressure regulator with minimum dead volume

Abstract

A pressure regulating valve for use in a high-pressure fluid flow line, comprises a cylindrical needle-housing structure that is slidable within a bore in a valve body. An external spring urges the needle-housing structure toward a valve seat at a selectable pressure. Contact between the needle-housing structure and the valve seat is prevented by an annular protrusion in the bore. Conduit means through the valve body, connectable to the flow line, permits passage of the flow-line fluid into the needle-housing structure. A cylindrical needle is disposed coaxially within the needle-housing structure, and is urged toward the valve seat by a spring located in the needle-housing structure. When the pressure of the flow-line fluid entering the needle-housing structure exceeds the selected pressure urging the needle-housing structure toward the valve seat, the needle-housing structure assumes a position at which the needle remains spaced apart from the valve seat. However, when the pressure of the flow-line fluid falls below the selected pressure, the needle-housing structure is thereby moved to a position at which the needle is urged into contact with the valve seat. Substantially the entire interior volume of the needle-housing structure is directly in the path of the flow-line fluid, so that no 'dead volumes' or pockets of fluid can accumulate therein.