Patent ID: 6745794
Filing Date: 2004-06-08
Classification: F16K,F25D,G05D,Y10T

Abstract:
A flow control valve to control fluid flow comprising:a valve housing having a primary passageway for the fluid flow and a valve stem barrel; a valve guide located within said valve stem barrel and having a central opening; a valve seat located within said primary passageway; a primary valve operable for movement between a closed position against said valve seat and an open position spaced from said valve seat to control flow rate of the fluid flow between lower flow rates as said primary valve is moved towards the closed position and higher flow rates as said primary valve is moved towards said open position; a secondary passageway defined at least by an orifice situated within said primary valve to allow for an ever more increasing passage of said fluid flow through said secondary passageway as said primary valve is moved towards said closed position; a secondary needle valve to project into said orifice and thereby to meter the ever more increasing passage of fluid flow within said secondary passageway; a valve stem to move said primary valve between said open and closed positions and to regulate a degree to which said secondary needle valve projects into said orifice, thereby to control the ever increasing passage of fluid flow and therefore, the fluid flow at the lower flow rates; said valve stem, at one end, projecting through said central opening and having an enlarged head; said primary valve connected to said valve guide such that said primary valve is spaced from said valve guide with said orifice located opposite to said enlarged head of said valve stem; said secondary needle valve connected to said enlarged head of said valve stem so that when said primary valve is in the fully closed position, movement of the valve stem adjusts the degree to which said secondary needle valve projects into said orifice; and a spring to bias said valve guide against said enlarged head of said valve stem so that movement of said valve stem moves said valve guide and said primary valve.