Vacuum demand valve

摘要

A vacuum demand valve for delivering a flowable material is disclosed. The valve has a housing having a proximal end, a distal end, an intermediate segment therebetween defining a passageway wherein the flowable substance can flow from the proximal end to the distal end. The housing can be a tubing. A valve member is located along the intermediate segment. The valve member has a closed condition wherein the flow of the flowable material from the proximal end to the distal end is stopped and an open condition wherein the flow of the flowable material from the proximal end to the distal end is unstopped. The valve member is biased in the closed condition and is responsive to a partial vacuum provided by the user through the passageway for placing the valve member in the open condition.