Air purge pump dispenser
AssigneeBespak PLC
InventorMiro S. Cater
Life of this patent
Estimating the term…
Abstract
Pump apparatus for delivering water based formulations as an aerosol spray provides for quantities of liquid and air to be pressurized in separate chambers by pump action. Liquid is dispensed through an orifice via a dispensing channel which in one embodiment is purged during a terminal part of the actuating stroke by the release of air through the dispensing channel. In the second embodiment air and liquid are mixed during the actuating stroke so as to be dispensed together and during a return stroke air is sucked through the dispensing channel to remove residual liquid. The air purging action prevents the build-up of deposits in the dispensing channel and orifice.
Claims28
Dispensing apparatus for dispensing liquid by pump action as an atomized spray, the apparatus comprising a body defining a first cylinder within which a first piston is reciprocatably located to define a first chamber of variable volume and which in use contains a quantity of liquid to be dispensed;
- the body further defining a second cylinder within which a second piston is reciprocatably located to define a second chamber of variable volume and which in use contains a quantity of air;
- actuating means operable during an actuating stroke to move the respective pistons in tandem in a direction such that the volumes of the respective chambers are reduced and during a return stroke to return the pistons to respective rest positions in which the respective chambers are expanded;
- liquid valve means operable to admit liquid to the first chamber during at least part of the return stroke and release pressurized liquid therefrom during at least part of the actuating stroke, the liquid valve means including a liquid exit port for the release of liquid from the first chamber;
- channel means defining a discharge orifice and a dispensing channel communicating between the liquid exit port and the discharge orifice;
- and
- air conduit means defining an air conduit communicating between the second chamber and the dispensing channel during at least part of the actuating stroke, whereby in use, air pressurized in the second chamber is conducted via the channel through the discharge orifice, wherein the liquid valve means is operable to close the liquid exit port before completion of the actuating stroke such that during a terminal part of the actuating stroke, the release of liquid from the first chamber is arrested.
Dispensing apparatus for dispensing liquid by pump action as an atomized spray, the apparatus comprising a body defining a first cylinder within which a first piston is reciprocatably located to define a first chamber of variable volume and which in use contains a quantity of liquid to be dispensed:
- the body further defining a second cylinder within which a second piston is reciprocatably located to define a second chamber of variable volume and which in use contains a quantity of air;
- actuating means operable during an actuating stroke to move the respective pistons in tandem in a direction such that the volumes of the respective chambers are reduced and during a return stroke to return the pistons to respective rest positions in which the respective chambers are expanded;
- liquid valve means operable to admit liquid to the first chamber during at least part of the return stroke and release pressurized liquid therefrom during at least part of the actuating stroke, the liquid valve means including a liquid exit port for the release of liquid from the first chamber;
- channel means defining a discharge orifice and a dispensing channel communicating between the liquid exit port and the discharge orifice;
- and
- air conduit means defining an air conduit communicating between the second chamber and the dispensing channel during at least part of the actuating stroke, whereby in use, air pressurized in the second chamber is conducted via the channel through the discharge orifice, wherein the air conduit is continuously in communication with the dispensing channel via an air exit port which remains continuously open.
A method of dispensing a liquid by pump action of a dispensing apparatus, the method comprising the steps of pressurizing a quantity of the liquid in a first chamber by movement of a first piston to reduce the volume of the first chamber during an actuating stroke of the apparatus, pressurizing a quantity of air in a second chamber by movement of a second piston in tandem with the first piston during the actuating stroke, releasing pressurized liquid from the first chamber into a dispensing channel by operation of a liquid valve means such that liquid flows through the dispensing channel and is dispensed from a discharge orifice, releasing pressurized air from the second chamber into the dispensing channel during at least part of the actuating stroke, wherein the liquid valve means is closed during a terminal part of the actuating stroke, and releasing air from the second chamber during the terminal part of the actuating stroke to thereby purge the dispensing channel of liquid.
A method of dispensing a liquid by pump action of a dispensing apparatus, the method comprising the steps of pressurizing a quantity of the liquid in a first chamber by movement of a first piston to reduce the volume of the first chamber during an actuating stroke of the apparatus, pressurizing a quantity of air in a second chamber by movement of a second piston in tandem with the first piston during the actuating stroke, releasing pressurized liquid from the first chamber into a dispensing channel by operation of a liquid valve means such that liquid flows through the dispensing channel and is dispensed from a discharge orifice, releasing pressurized air from the second chamber into the dispensing channel during at least part of the actuating stroke, and allowing air to enter the second chamber via the dispensing channel during a return stroke of the apparatus in which the volume of the first and second chambers are increased such that residual liquid in the dispensing channel is sucked into the second chamber.
An air purge pump, comprising:
- a first cylinder having open upper and lower ends;
- a second cylinder having a diameter greater than that of the first cylinder and having open upper and lower ends, the lower end of the second cylinder merging with the upper end of the first cylinder, an inner surface of the second cylinder adjacent the upper end of the second cylinder having an air conduit;
- a third cylinder having a diameter smaller than that of the first cylinder and having an open upper end and a lower end which is closed except for a central opening, the lower end of the first cylinder merging with the upper end of the third cylinder;
- an elongated stem having an upper portion which extends upwardly through the upper end of the second cylinder and having a lower portion which extends downwardly through the first and second cylinders with a lower end which is peripherally engageable with an inner surface of the third cylinder;
- a first piston having an upper hollow extension with an open upper end, the upper portion of the elongated stem extending within and being spaced from the upper extension, thus defining a liquid conduit therebetween, the first piston having a lower extension extending downwardly through the second cylinder into the first cylinder with a lower end which is peripherally engageable with an inner surface of the first cylinder;
- and a second piston having a hollow upper section, the upper extension of the first piston extending within and being spaced from the upper section of the second piston, thus defining an air conduit therebetween, the second piston having a lower section with an outward extension which is peripherally engageable with an inner wall of the second cylinder.
Dependencies are inferred from the claim text.