Spring biased check valve

Claim 1

A CHECK VALVE HAVING A BODY MADE OF HARD, SUBSTANTIALLY UNYIELDING MATERIAL, SAID BODY HAVING A REAR AND A FORWARD END, A PASSAGE THROUGH THE BODY FROM ITS REAR TO ITS FORWARD END, A FIRST ANNULAR SEAT CONVERGING IN THE DIRECTION TOWARD THE FORWARD END OF THE BODY LONGITUDINALLY OF THE PASSAGE AND DISPOSED ON THE INNER WALL OF THE PASSAGE TRANSVERSELY TO THE AXIS THEREOF, THE FIRST PART OF THE PASSAGE, REARWARDLY OF THE LARGER DIAMETERED END OF THE FIRST SEAT, HAVING A FIRST, LARGER DIAMETER, THE SECOND PART OF THE PASSAGE, FORWARDLY OF THE SMALLER DIAMETERED END OF THE FIRST SEAT, HAVING A SECOND, SMALLER DIAMETER, A VALVE ELEMENT IN THE PASSAGE IN THE BODY, SAID VALVE ELEMENT BEING MADE OF RELATIVELY SOFT RESILIENT RUBBER-LIKE MATERIAL, THE VALVE ELEMENT HAVING A SECOND ANNULAR SEAT THEREON CONVERGING IN THE SAME DIRECTION AS THE FIRST SEAT, THE FIRST AND SECOND SEATS BEING ADAPTED TO SEAL THE PASSAGE AGAINST ESCAPE OF FLUID OUTWARDLY THERETHROUGH WHEN THE VALVE ELEMENT IS THRUST FORWARDLY AND TO PERMIT THE FLOW OF FLUID THROUGH THE PASSAGE WHEN THE VALVE ELEMENT IS MOVED REARWARDLY WITH RESPECT TO THE VALVE BODY, THE VALVE ELEMENT HAVING FIRST AND SECOND PARTS WHICH LOOSELY BUT GUIDINGLY ARE ENGAGED BY THE FIRST AND SECOND PARTS, RESPECTIVELY, OF THE PASSAGE, THE SAID FIRST PART OF THE VALVE ELEMENT EXTENDING A SUBSTANTIAL DISTANCE INTO THE FIRST PART OF THE PASSAGE FOR SELECTIVE ENGAGEMENT BY A VALVE ELEMENT UNSEATING MEMBER INTRODUCED INTO THE OUTER END OF THE SECOND PART OF THE PASSAGE, ABUTMENT MEANS ON THE VALVE BODY SPACED REARWARDLY BEYOND THE FIRST, LARGER DIAMETERED PART OF THE VALVE ELEMENT, AND MEANS LIGHTLY DIAMETERED PART OF THE VALVE ELEMENT FORWARDLY TOWARD ITS SEALING POSITION COMPRISING A DISC-LIKE BODY OF RESILIENT POROUS FOAMED PLASTIC MATERIAL INTERPOSED BETWEEN THE ABUTMENT MEANS AND THE FIRST, LARGER DIAMETERED PART OF THE VALVE ELEMENT, SAID DISC-LIKE BODY OVERLYING A PREDOMINANT PORTION OF THE AREA OF SAID FIRST PART OF THE VALVE ELEMENT.