A valve assembly comprising: a sealing housing , which sealing housing includes a lower housing portion and an upper housing portion , the upper housing comprising a main body that is adapted to encircle a portion of a pipe , an upper surface , and an integral valve housing section disposed generally therebetween, the integral valve housing section having a slot therein; a valve comprising an upper valve surface and a lower valve surface , the valve being movable in the slot in the integral valve housing section between an open position and a closed position, the slot comprising an upper slot surface and a lower slot surface ; and a plurality of biasing members movably positioned within the integral valve housing section and configured to urge the valve toward one of the upper slot surface and the lower slot surface , wherein the valve is configured to be movable axially along a longitudinal axis of the pipe , and the valve is a flat plate member, and wherein each of the plurality of biasing members resides within a threaded bore that extends through the outer surface of the upper housing portion and into the slot , wherein the biasing member and the respective threaded bore are at least partially offset from the valve , in order for a biasing force to act on the upper or lower slot surfaces of the valve , wherein each biasing member includes an elongate, cylindrical shank separating a tip from a distal end , and is a threaded cylinder movably residing within the threaded bore , wherein the plurality of biasing members are disposed on one same side of the pipe , characterized in that the plurality of biasing members comprise four biasing members including a first biasing member positioned at a first corner of the valve , the second biasing member positioned at a second corner of the valve , a third biasing member positioned along a first edge of the valve , and a fourth biasing member positioned along a second edge of the valve . a sealing housing , which sealing housing includes a lower housing portion and an upper housing portion , the upper housing comprising a main body that is adapted to encircle a portion of a pipe , an upper surface , and an integral valve housing section disposed generally therebetween, the integral valve housing section having a slot therein; a valve comprising an upper valve surface and a lower valve surface , the valve being movable in the slot in the integral valve housing section between an open position and a closed position, the slot comprising an upper slot surface and a lower slot surface ; and a plurality of biasing members movably positioned within the integral valve housing section and configured to urge the valve toward one of the upper slot surface and the lower slot surface , wherein the valve is configured to be movable axially along a longitudinal axis of the pipe , and the valve is a flat plate member, and wherein each of the plurality of biasing members resides within a threaded bore that extends through the outer surface of the upper housing portion and into the slot , wherein the biasing member and the respective threaded bore are at least partially offset from the valve , in order for a biasing force to act on the upper or lower slot surfaces of the valve , wherein each biasing member includes an elongate, cylindrical shank separating a tip from a distal end , and is a threaded cylinder movably residing within the threaded bore , wherein the plurality of biasing members are disposed on one same side of the pipe , characterized in that the plurality of biasing members comprise four biasing members including a first biasing member positioned at a first corner of the valve , the second biasing member positioned at a second corner of the valve , a third biasing member positioned along a first edge of the valve , and a fourth biasing member positioned along a second edge of the valve . <EOS>