Metering valve

A metering valve for regulating a gas flow rate comprising:

• (a) a valve body having first and second inner cylindrical chambers;
• (b) inlet and outlet ports in said valve body in communication with said first and second inner cylindrical chambers respectively;
• (c) a transverse wall portion between said first and second inner chambers, said wall portion having a passageway extending therethrough to provide communication between the first and second inner chambers, said passageway having a first section being partially threaded and a second tapered section adjacent said first section;
• (d) a valve seat disposed in said passageway having a cylindrical orifice extending therethrough, and an external configuration conforming to said tapered section;
• (e) a valve stem having a groove thereon to cooperate with said valve seat, said groove being tapered and extending longitudinally on said shaft, said groove increasing in depth at a pre-selected rate per unit-length with the maximum depth being at a base end of said shaft, whereby axial movement of said stem regulates the gas flow rate through a preset range between said first and second chambers;
• (f) torque reduction means comprising a cylindrical valve stem having a diameter from 0.093-0.1252 inches for decreasing the torque required to move the valve stem, whereby precise settings of the gas glow can be achieved;
• (g) a bellows disposed in said second chamber concentric with said valve stem, a plug portion disposed on one end of said bellows to abut said transverse wall portions and close said passageway when said bellows is in the extended position;
• (h) micrometer means extending outside of said valve body for moving said valve stem in the axial direction.