Valve for viscous fluids

Claim 1

A VALVE FOR DISPENSING A HIGHLY VISCOUS FLUID MATERIAL COMPRISING A MEMBER HAVING AN INLET AND AN OUTLET FOR THE MATERIAL, A SINGLE MEANS FOR OPENING AND CLOSING THE INLET TO PERMIT THE PASSAGE OF A PREDETERMINED QUANTITY OF THE FLUID AND FOR CREATING A SUCTION AGAINST THE FLUID IN THE MEMBER AFTER THE INLET IS CLOSED TO PREVENT DISCHARGE OF EXCESS AMOUNTS OF FLUID FROM THE OUTLET, SAID MEANS COMPRISES A SLEEVE MOUNTED FOR RECIPROCATION IN THE PASSAGEWAY, SAID SLEEVE HAVING AN OPENING ON ONE SIDE ADOPTED TO REGISTER WITH SAID INLET IN ONE POSITION OF ITS MOVEMENT RELATIVE THERETO, A PISTON MOUNTED FOR RECIPROCATION IN SAID SLEEVE, SAID PISTON HAVING AN OPENING IN THE SIDE THEREOF ADAPTED TO REGISTER WITH THE SAID OPENING AND SLEEVE IN ONE POSITION OF ITS MOVEMENT RELATIVE TO THE SLEEVE, SAID PISTON HAVING A PASSAGEWAY EXTENDING THROUGH IT FROM ITS SAID OPENING TO ITS LOWER END, THE LOWER END OF SAID SLEEVE COMPRISING AN OUTLET APART FROM SAID INLET FOR MATERIAL INTRODUCED THROUGH THE INLET, SEALING MEANS BETWEEN THE PISTON AND SLEEVE, AND MEANS FOR CYCLICLY RECIPROCATING THE SLEEVE AND PISTON RELATIVE TO THE BODY AND RELATIVE TO EACH OTHER SO AS TO OPEN THE INLET FOR COMMUNICATION WITH THE OUTLET FOR A PERIOD IN EACH CYCLE OF OPERATION, THEN CLOSING THE INLET AND, WHILE THE INLET IS CLOSED, MOVE THE PISTON UPWARD RELATIVE TO THE SLEEVE TO CREATE A SUCTION AGAINST THE FLUID MATERIAL ABOVE THE OUTLET.