Patent ID: 8146617

Claim:
A check valve comprising: a valve body having a tube having a first end; a second end; an inner surface; a middle; a sealing protrusion formed annularly on and protruding from the inner surface at the middle of the tube and having; an oblique end facing the first end of the tube; an abutting end facing the second end of the tube; an oblique surface formed on the oblique end of the sealing protrusion; and a shoulder formed on the abutting end of the sealing protrusion; a nozzle combined with and covered on the first end of the tube and having a cap abutting the first end of the tube and having a center; an inner surface; an insert hole defined through the center of the cap; multiple outlets defined through the cap; and a valve seal abutting against the shoulder and the inner surface of the tube and having an internal diameter; a piston mounted in the valve body and having a shaft mounted slidably through the insert hole and having a disk protruding around the middle of the shaft and having a sealing groove defined around the disk; a plug end mounted in the second end of the tube; a sealing ring mounted in the sealing groove of the disk and selectively abutting the oblique surface of the sealing protrusion; a plug being a conic frustum, mounted on the plug end of the shaft and having a peripheral surface mounted around the plug; a first end of the plug having an outer diameter smaller than the internal diameter of the valve seal; a second end of the plug opposite to the first end of the vale plug and having an outer diameter larger than the outer diameter of the first end of the plug; and a spring mounted around the shaft and having a proximal end abutting against the inner surface of the cap; a distal end opposite to the proximal end.