Metering pump and combination two-section pinch-off aspirator valve

A non-drip valve assembly for dispensing an accurately measured amount of fluid from an adjustable pump, said valve assembly comprising:

• a housing having an inlet and an outlet fluidly connected by a valving passage;
• tube means within said passage, said tube means having an intermediate closed section to divide the tube means into a first section between the closed section and the inlet and a second section between the closed section and the outlet;
• a first plurality of openings in said tube means upstream and downstream of said closed section;
• a second plurality of openings in the second section of the tube means downstream of said closed section and said first plurality of openings;
• resilient tube means surrounding said tube means in said valving passage;
• seal means between the housing and said resilient tube means upstream of the first openings, intermediate said first and second openings and downstream of said second openings, said resilient tube means being peripherally spaced from the surfaces of the valving passage in the area of the first and second plurality of openings and being normally spaced from said openings cooperating with said tube means defining a fluid directing passage around the periphery of said tube means closed section and defining a fluid receiving chamber around the periphery of said tube means at said second plurality of openings;
• a first inlet port in the housing communicating with the valving passage adjacent the fluid directing passage at said first plurality of openings;
• a second inlet port in the housing communicating with the valving passage adjacent the fluid receiving chamber at said second plurality of openings;
• valve means for alternately applying fluid pressure at said first and second ports to allow the resilient tube means to engage said closed section closing said fluid directing passage upon application of pressure and unseal the openings upon removal thereof whereby a measured amount of fluid will be dispensed between said first and second sections when the first air inlet port is not pressurized and said second port is pressurized to seal said resilient tube means against the second plurality of openings closing said fluid chamber, pressure being alternately applied to said ports to close said fluid directing passage and seal the first plurality of openings in said tube means to stop the flow of material to said second section, and at the same time venting from said second inlet port through said valve means whereby the resilient tube means moves away from the second plurality of openings opening said fluid receiving chamber to create a suction in said second section suctioning fluid through said second plurality of openings into said fluid receiving chamber thereby preventing drip from said valve assembly.

A two section pinch-off aspirator valve for dispensing an accurately measured amount of viscous material from a container as delivered by an adjustable stroke pump comprising:

• a housing;
• inlet and outlet openings in said housing;
• said inlet means being fluidly connected to said container, a support tube within said housing extending between the inlet and outlet openings;
• said support tube having a closed section a distance below the inlet opening to divide the support tube into a lower and upper section;
• said support tube having a first plurality of openings above and below said closed section to connect the upper section to the lower section, said support tube having a second plurality of openings in the lower section;
• resilient tube means surrounding said support tube;
• said support tube being smaller in diameter adjacent said first and second plurality of openings in said support tube;
• said support tube and said resilient tube means cooperating defining a passage around the periphery of said support tube closed section and defining a chamber around the periphery of said support tube at said second plurality of openings;
• said housing having a first air inlet port adjacent said first plurality of openings in said support tube which surrounds said resilient tube means adjacent the passage around said support tube closed section and said openings, and a second air inlet port that surrounds said resilient tube means adjacent the chamber around the periphery of said support tube and said second plurality of openings;
• a nozzle secured to said support tube to dispense the viscous material;
• valve means to exhaust air from said first inlet port to allow the resilient tube means to move away from the smaller diameter areas in said support tube to open said passage and the first plurality of openings in said support tube and dispense a measured amount of material to the lower section of the support tube while air is applied by said valve means to the second air inlet port to force said resilient tube to close the chamber and the second plurality of openings in said support tube, and air being applied by said valve means to said first inlet port to close the passage and the first plurality of openings in said support tube to stop the flow of material to the lower section of said support tube, and at the same time air being vented from said second inlet port through said valve means whereby the resilient tube moves away from the second plurality of openings in said support tube opening said chamber to create a suction in the lower section of said support tube suctioning material through the second plurality of openings into said chamber to thereby prevent drip from said nozzle.