The bender means may include a ceramic acoustic tone transducer. The nozzle may be generally conically shaped and it is preferred that the nozzle region be no larger than 0.1 cubic centimeter. The dispenser may further include a storage chamber for holding fluid to 5 be dispensed and channel means connecting the storage chamber in the reservoir region of the nozzle chamber.
Means may be provided for controlling the operation of the bender means. Such means for controlling typically include timer means for operating the bender 10 means at predetermined times and/or sensor means for sensing a predetermined physical parameter. There are means responsive to such sensor means for operating the bender means when the predetermined physical parameter is sensed. Means may also be provided for 15 sensing that the fluid in the nozzle has dropped below a predetermined level. Means, responsive to said means for detecting, may also be provided for indicating that the fluid level has dropped below the predetermined level. The means for detecting may include a pair of ^ electrodes for sensing the presence of the fluid between them.
DISCLOSURE OF PREFERRED EMBODIMENT
Other objects, features and advantages will occur from the following description of a preferred embodiment and the accompanying drawings, in which:
FIG. 1 is an axonometric view of a replaceable cartridge which includes the aerosol dispenser according 3Q to this invention and a power supply unit which receives the replaceable cartridge;
FIG. 2 is a cross-sectional view taken along line 2—2 of FIG. 1 of one embodiment of the aerosol dispenser;
FIG. 3 is a schematic diagram of a power supply and 35 control circuitry for automatically operating the aerosol dispenser of FIG. 2;
FIG. 4 is a view similar to that of FIG. 2 of an alternative embodiment of a low-voltage aerosol dispenser which employs a perforated flexible element in the 40 nozzle chamber;
FIG. 5 is a view similar to that of FIG. 2 of a further alternative embodiment of the aerosol dispenser which includes a one-way flap valve;
FIG. 6 is a view similar to that of FIG. 2 of an alter- 45 native aerosol dispenser in which the nozzle chamber is formed from an integral diaphragm and flexible wall;
FIG. 7 is a view similar to that of FIG. 2 of an additional alternative aerosol dispenser employing a generally concave diaphragm having a substantially flat bot- 50 torn;
FIG. 8 is a cross-sectional view of an another alternative aerosol dispenser which utilizes a substantially flat diaphragm; and
FIG. 9 is a schematic view of a circuit for detecting 55 and indicating that the fluid in the nozzle chamber has dropped below a predetermined level.
An aerosol dispenser according to this invention may be accomplished with a nozzle chamber for holding fluid to be dispensed. The chamber includes a dia- 60 phragm, which is typically a 2-5 mil thick shim composed of stainless steel or similar material. An aerosoldispensing nozzle is disposed in the diaphragm. Preferably, the nozzle is generally conically shaped. The nozzle chamber includes a nozzle region proximate the nozzle 65 and a larger reservoir region interconnected to, and preferably surrounding, the nozzle region. Typically, the nozzle region is no larger than 0.1 cubic centimeter.
The diaphragm may include a concave section and a convex portion centrally disposed in the concave section. The nozzle is preferably located centrally in the convex portion. There is a restrictive passage means for introducing fluid from the reservoir region to the nozzle region and restricting backflow from the nozzle region to the reservoir region.
Means which preferably include piezoelectric bender means are provided for driving fluid from the reservoir region to the nozzle region and from the nozzle region through the nozzle to create an aerosol spray. A preferred bender is a ceramic acoustic-tone transducer (CATT) disk. A typical CATT disk includes a brass shim stock disk which is, for example, 1| inches in diameter and 10 mils thick. A one-inch diameter, 10 mils thick piezoelectric wafer disk is bonded by any acceptable means to the shim stock and electrodes are attached to the shim stock and to the opposite side of the piezoelectric wafer. The shim stock may itself serve as one of the electrodes. The resonant frequency of such CATT disks is typically from 2 to 4 KHz.
The CATT disk or other bender may form at least one of the walls of the nozzle chamber. The diaphragm typically forms another wall and the remaining walls may be composed of ABS plastic or similar material. In such embodiments the restrictive passage means may be formed between the bender and the bottom of the concave section of the diaphragm.
In alternative embodiments a very thin flexible member, composed of, for example, 2 mils thick saran plastic or similar material is interposed between the diaphragm and the bender to divide the reservoir region into first and second portions. There are means for transmitting bender deflection to flex the flexible member and pressurize the fluid in the nozzle region of the nozzle chamber. The means for transmitting may include some of the fluid in the first reservoir portion between the bender means and the flexible means. When the bender is deflected, that fluid is pressurized to flex the flexible member. In turn, the fluid in the nozzle region is pressurized. Alternatively, an actuator member may extend between and be attached to one of the bender means and the flexible member. The actuator means responds to deflection of the bender to flex the flexible member. The flexible member is typically perforated so that the first and second portions of the reservoir region can communicate with each other. In such embodiments the restrictive passage is typically formed between the flexible member and the bottom of the concave portion of the diaphragm.
In still another embodiment an integral flexible wall and diaphragm may be provided and the bender means may be disposed outside of the nozzle chamber. The restrictive means in such devices are typically formed between the flexible wall portion and the bottom of the concave portion of the diaphragm.
A further embodiment includes valve means for introducing fluid from the reservoir region to the nozzle region and for restricting backflow from the nozzle region to the reservoir region. Such valve means may include a unidirectional valve such as a flapper, check or ball valve.
In certain embodiments the convex diaphragm section may be omitted and a concave portion may be employed which has a substantially flat central region in which the nozzle is disposed. In yet another embodiment the concave diaphragm may be eliminated and a pressurizing member attached at one end to the bender