Flow control valve

A valve which allows for two-direction flow comprises:

• a housing, said housing defining an axial flow channel and a cylinder chamber wherein the cylinder chamber is a lateral extension of the axial flow channel;
• a reciprocal hollow closure member disposed within said axial flow channel, said closure member having piston means mounted thereon and received in said cylinder chamber for reciprocating said closure member;
• seal means mounted on said housing defining said axial flow channel on either side of said cylinder chamber for sealingly mounting said closure member in said axial flow channel and at the same time sealing said cylinder chamber from said axial flow channel;
• a stationary flow control means having substantially identical opposed flow impact surface configurations which allows for two-directional substantially linear flow within said axial flow channel under substantially similar conditions wherein the flow control means is arranged within the axial flow channel, so as to allow for a substantially constant flow characteristic gradient at all positions of the closure member between 5% and 100% open, said flow control means having a recess for receiving a flow impact means, said flow impact means having (1) a stem portion received within said recess, (2) a conical shaped impact surface of desired configuration to obtain desired flow characteristics and (3) an annular conical packing sealing surface adjacent said impact surface;
• and
• drive means for displacing said piston means and correspondingly said closure member in an axial direction for selectively sealing and unsealing said closure member on said packing sealing surface of said flow control means.