A foamer pump for dispensing foam has a simple construction and utilizes a single piston to reduce the volume of both a fluid chamber and an air chamber. A portion of the actuating mechanism helps to unseat a check valve at the outlet of the fluid chamber. The foamer pump has a fluid chamber, and an outlet of the fluid chamber is connected to a mixing chamber. An air chamber has an air channel that connects the air chamber to ambient air in a first position and to the mixing chamber in a second position. A piston causes the volume of the air chamber and the liquid chamber each to be reduced, forcing air from the air chamber and foamable fluid from the liquid chamber into the mixing chamber where they blend to form an air/liquid mixture.
1. A dispensing pump constructed and arranged for assembly to a container for dispensing a composition of air and liquid, wherein a supply of said liquid is in said container, said dispensing pump comprising:
closure means for assembling said dispensing pump to said container;
an actuator received by a portion of said closure means;
an accumulator assembled with said closure means, said accumulator defining a liquid flow passage;
a piston assembled with said accumulator together defining an air chamber, said piston having a portion and said piston defining an air flow opening through said portion, said air flow opening being constructed and arranged for enabling air flow therethrough into said air chamber and for enabling a flow therethrough of air from within said air chamber for use in said composition;
a stem assembled with a portion of said actuator, said stem and said piston cooperatively defining an air passage;
first valve means for controlling the passage of liquid through said liquid flow passage;
second valve means for controlling the passage of air through said air passage; and
wherein said second valve means is constructed and arranged free of any elastomeric component which must deflect for any air valving function.
2. The dispensing pump of claim 1 wherein said first valve means is constructed and arranged free of any of elastomeric component which must deflect for any liquid valving function.
3. The dispensing pump of claim 1 wherein said second valve means includes a first sealing member and a second sealing member.
4. The dispensing pump of claim 3 wherein sealing engagement between said first sealing member and said second sealing member is achieved by an overlapping relationship between said first sealing member and said second sealing member.
5. The dispensing pump of claim 3 wherein said first sealing member is constructed and arranged as a generally cylindrical ridge.
6. The dispensing pump of claim 5 wherein said second sealing member is constructed and arranged as a generally cylindrical ridge.
7. The dispensing pump of claim 1 wherein said first valve means includes a first check valve cooperating with said liquid flow passage.
8. The dispensing pump of claim 7 wherein said first valve means further includes an inlet check valve cooperating with said liquid flow passage.
9. A dispensing pump constructed and arranged for assembly to a container for dispensing a composition of air and liquid, wherein a supply of said liquid is in said container, said dispensing pump comprising:
closure means for assembling said dispensing pump to said container;
an actuator received by a portion of closure means;
an accumulator assembled with said closure means;
a unitary piston cooperating with said accumulator to define an air chamber and including a scraper, a first sealing member, a flange member and a portion between said first sealing member and said flange member defining an air flow opening which is constructed and arranged for a flow therethrough of air from within said air chamber for use in said composition and for providing a path for make-up air into said air chamber; and
a stem assembled with said actuator and including a second sealing member, said stem being movable with said actuator for cooperating with said first sealing member.