Vacuum pump

Claim 1

A vacuum pump comprising a housing, a connection for admitting vacuum to said housing in one area thereof and a pair of check valves in a different area thereof, said check valves operating independently and oppositely to each other, an elastometric diaphragm in said housing, said diaphragm being in the form of a cup having a rim, a continuous sidewall, and a closed bottom, means securing the rim of said diaphragm to said housing continuously, dividing the same into a pair of chambers, a first chamber outside the cup including the vacuum connection and a second and separate chamber inside the cup including the check valves, a small hole to the atmosphere in a wall of said housing into the first chamber, said housing including a sidewall greater in diameter then the diameter of the cup, providing an annular space between the walls, said space being at least a part of the first chamber, vacuum from the vacuum connection acting upon said diaphragm to cause the same to stretch toward it and the cup walls to expand toward the housing wall reducing the volume of the first chamber and thereby causing fluid material to enter into the second chamber, the bottom of the cup being constructed and arranged to substantially cutoff the vacuum relative to said first chamber to provide that the pressure entering from the atmosphere overcomes the vacuum action and causes the diaphragm to snap back from its stretched condition expelling fluid in a jet through one of the check valves.