Fluid dispenser

摘要

A dispensing system includes a pump mechanism that has a liquid chamber, a liquid piston for delivering fluid to a mixing chamber, and a valve component biased to close the outlet from the liquid chamber. The pump mechanism also has an air chamber, and an air piston for delivering air to the mixing chamber. A bore allows passage of a mixture of the air and the liquid from the mixing chamber to a dispensing tube. A pump actuator moves the air piston and the liquid piston to propel a dose of the mixture of the air and the liquid through the bore and into the dispensing tube and to collapse a draw-back chamber. The draw-back chamber expands to draw the mixture of the air and the liquid from the dispensing tube into the draw-back chamber. The valve component is biased to close the first outlet before the draw-back chamber expands.

主权项

1. A dispensing system comprising:
a pump mechanism comprising a first inlet for delivering liquid from a container to the pump mechanism, the pump mechanism comprising a liquid chamber receiving the liquid from the first inlet, a liquid piston for delivering fluid from the liquid chamber to a mixing chamber through a first outlet; a valve component biased to close the first outlet, and a second inlet for delivering air to the pump mechanism, the pump mechanism comprising an air chamber receiving the air from the second inlet, an air piston for delivering air from the air chamber to the mixing chamber through a second outlet; a bore configured to allow passage of a mixture of the air and the liquid from the mixing chamber to a dispensing tube; a draw-back chamber; a passageway between the bore and the drawback chamber; a pump actuator movable between a first position and a second position to move the air piston and the liquid piston to propel a dose of the mixture of the air and the liquid through the bore and into the dispensing tube and to collapse the draw-back chamber, the draw-back chamber expanding to draw the mixture of the air and the liquid from the dispensing tube into the drawback chamber; the valve component being biased to close the first outlet before the draw-back chamber expands.