Dispenser, and refill
A dispenser capable of dispensing a fluid via a vertically-oriented piezo device comprises a reservoir containing a fluid to be dispensed, an outlet at a base portion of the reservoir, leading to a dispensing port that comprises a piezo element drivable to vibrate and thereby dispense fluid from the dispensing port, a bleed tube communicating at one end with the dispensing port, extending therefrom to a location above the dispensing port, and including a selectively closeable valve, and a source of below-atmospheric pressure to the portion of the reservoir above the fluid. Embodiments of refills suitable for such a dispensing apparatus are also described.
1. A dispensing apparatus, comprising;
a reservoir containing a fluid to be dispensed in an aerosol form;
an outlet at a base portion of the reservoir, leading along a conduit to a dispensing port at an end of the conduit;
the dispensing port comprising a piezo element which is porous, thereby to permit dispensing from a front side of the element, of fluid contacting the element on a rear side, which is located over the end of the conduit and closes the end of the conduit, and which is drivable to vibrate and thereby dispense fluid from the dispensing port, in use the arrangement being to allow fluid to flow by gravity from the reservoir through the conduit to the piezo element;
a bleed tube communicating at one end with the conduit, between the outlet and the closed end, and extending generally vertically from the conduit to a location above the dispensing port, and including a selectively closeable valve; and
a source of below-atmospheric pressure to the portion of the reservoir above the fluid.
2. A dispensing apparatus according to claim 1 in which the source of below-atmospheric pressure comprises a piston.
3. A dispensing apparatus according to claim 2 further comprising an openable cover concealing at least part of the apparatus, wherein the piston is operatively connected to the cover so as to impose below-atmospheric pressure to the reservoir on closing the cover.
4. A dispensing apparatus according to claim 1 further comprising an openable cover concealing at least part of the apparatus, wherein the selectively closeable valve is operatively connected to the cover so as to close the valve on closing the cover.
5. A dispensing apparatus according to claim 1 in which the source of below-atmospheric pressure comprises a piston, further comprising an openable cover concealing at least part of the apparatus, wherein the piston and the selectively closeable valve are operatively connected to the cover so as to impose below-atmospheric pressure to the reservoir and close the valve on closing the cover.