BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the disclosed methods and apparatuses, reference should be made to the embodiment illustrated in greater detail on the accompanying drawings, wherein:
FIG. 1 is a partial cross-sectional perspective view of an aerosol dispenser assembly made in accordance with this disclosure.
FIG. 2 is a partial front sectional view of an aerosol assembly made in accordance with this disclosure
FIG. 3 is a front elevational view of an actuator cap made in accordance with this disclosure
FIG. 4 is an enlarged partly sectional view of the actuator cap shown in FIG. 3.
FIG. 5 is an exploded cross-sectional view of the actuator cap, stem and insert shown in FIGS. 3 and 4.
FIG. 6 is a front view of the insert shown in FIGS. 4 and 5.
FIG. 7 is a rear view of the insert shown in FIGS. 4-6.
FIG. 8 is a cross-sectional view taken substantially along line 8-8 of FIG. 7.
FIG. 9 is a partial cross-sectional view of yet another aerosol dispenser assembly made in accordance with this disclosure.
FIG. 10 is a cross-sectional view of the insert used in the aerosol dispenser valve shown in FIG. 9
FIG. 11 is a rear view of the insert shown in FIG. 10.
FIG. 12A is a partial sectional view of the actuator cap shown in FIG. 1, particularly illustrating the placement of a heater adjacent in the insert at least partially surrounding the swirl chamber.
FIG. 12B is a side sectional view of the insert shown in FIG. 12A
FIG. 13 is a side sectional view of an insert equipped with a break-up bar.
FIG. 14 is another side sectional view of the insert shown in FIG. 13.
FIG. 15 is another side sectional view of the insert shown in FIGS. 13-14.
FIG. 16 is a front plan view of the insert shown in FIGS. 13-15
FIG. 17 is a rear plan view of the insert shown in FIGS. 13-16.
FIG. 18 is a front perspective view of the insert shown in FIGS. 13-17.
FIG. 19 is a rear perspective view of the insert shown in FIGS. 13-18.
It should be understood that the drawings are not to scale and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views In certain instances, details which are not necessary for an understanding of the disclosed methods and apparatuses or which render other details difficult to perceive may have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiments illustrated herein
DETAILED DESCRIPTION OF THE DISCLOSURE
As shown in FIGS. 1 and 2, an aerosol dispenser assembly 10 includes a container 11 covered by a mounting cup 12. A mounting gasket 13 is disposed between an upper rim (not shown) of the container 11 and the underside of the mounting cup 12. A valve assembly 14 is used to selectively release the contents from the container 11 to the atmosphere. The valve assembly comprises a valve body 15 and a valve stem 16. The valve stem 16 includes a lower end 16a that is mounted through a return spring 17. An actuator cap 8 is mounted on top of the valve stem 16 and defines a primary passageway 19. The actuator cap 18 also defines an exit orifice shown generally at 22 and which will be discussed in greater detail below.
The valve body 14 is affixed to the underside of the mounting cup 12 by a friction fit and the valve stem 16 extends through the friction cup 12. The actuator cap 18 is frictionally fitted onto the upwardly extending portion of the valve stem 16. The lower end of the valve body 15 is connected to a dip tube 23. Gaskets may or may not be required between the valve body 15 and the mounting cup 12 and between the valve stem 16 and the mounting cup 12, depending upon the materials used for each component Suitable materials will be apparent to those skilled in the art that will permit a gasket-less construction Similarly, gaskets or seals are typically not required between the actuator cap 18 and the upper portion of the valve stem 16.
While the dispenser assembly 10 of FIGS. 1-2 employs a vertical action-type cap 18, it will be understood that other actuator cap designs may be used such as an actuator button with an integral over cap, a trigger actuated assembly, a tilt action-type actuator cap or other designs.
In operation, when the actuator cap 18 is depressed, it forces the valve stem 16 to move downward thereby allowing liquid product to be dispensed. The propellant forces the liquid product up the dip tube 23 and into the valve body 15 via the orifice or passageway 24. From the valve body 15, the liquid product is propelled through the stem orifices 26, out the passageway 27 through the valve stem 16 and through the primary passageway 19 of the actuator cap to the exit orifice 22. Preferably, two valve stem orifices 26 are employed although a single valve stem orifice or up to four valve stem orifices may be used. Multiple valve stem orifices 26 provide greater flow and superior mixing of the product.
The use of an insert and a post within the actuator cap 18 is not specifically shown in FIG. 1 but is illustrated in FIGS. 3-14 below However, a heater 43 is shown schematically in FIG. 1. Typically, aerosol dispensers include a post-like structure built into the actuator cap and an insert that covers the post in the exit orifice. A heater can be employed in the insert or in the actuator cap around the insert to provide heat to the swirl chamber as described below Also, the insert itself may be metallic for induction or resistive heating One example of such construction is illustrated in FIGS. 3-8.
Specifically, referring to FIG. 3, an actuator cap 118 is disclosed with a primary passageway 119. Disposed within the passageway 119 is a post 131 that is connected to or formed integrally from the actuator cap 118. The post 131 mateably receives an insert 132 as illustrated in FIGS. 4-5. In the embodiment illustrated in FIGS. 3-5, the actuator cap 118 fits directly onto the valve stem 116 without the inclusion of a break-up bar (see reference numeral 21 in FIG. 1). Disposed between the insert 132 and the post 131 is a small swirl chamber shown at 133 in FIG. 4. Communication is provided to the swirl chamber 133 through the connecting passage 134. Details regarding the construction of the insert or suitable inserts that may be used in accordance with this disclosure are provided in FIGS. 6-8, 10 and 13.
A heater 143 is disposed within the insert 132 and surrounds the swirl chamber 133 to heat the prospect/propellant mixture passing through the swirl chamber 133. As discussed below in connection with FIGS. 12-14, the heating generates bubbles of propellant in the exit stream, causing cavitation, the formation of unstable liquid product ligaments and eventually, small droplets of product having diameters of less than 35 μm. Further, the insert 132 may be fabricated from metal so that the entire insert 132 serves as a resistance heater connected to tho electrical leads 144, 145.
Turning to FIGS. 6-8, the insert 132 is shown in greater detail. The recess 133a provides the space necessary for the swirl chamber 133 shown in FIG. 4. The cylindrical sidewall 135 includes a raised portion that results in a step 136 that engages a catch 137 built into the actuator cap 118 thereby enabling the insert 132 to be press-fit into the actuator button 118. The insert 132 has a front wall 138 and a discharge orifice 139. Additional details regarding the construction of the insert 132 and post 131 as shown in FIGS. 3-8 can be found in U.S. Pat. No. 4,071,196.
The heating element 143 and electrical leads 144, 145 are shown in FIG. 8 However, as noted above, the entire insert 132 may be fabricated from a high resistance metallic material and therefore the entire insert 132 may serve as a resistance heater. The entire insert 132 may also serve as an induction heating element.
Turning to FIGS. 9-12, a similar construction is shown whereby the valve body 215 is mounted onto a dip tube 223 and beneath a valve stem 216. The actuator cap 218 also includes a post 231 which mateably receives an insert 232 to provide a swirl chamber 233 therebetween as shown in FIG. 9. A stem orifice is shown at 226 and a return spring at 217 The mounting cup and gasket are shown at 212, 213, respectively.
Details of the insert 232 are provided in FIGS. 10-12. The insert 232 includes a cylindrical wall 235 with a barb or catch shown at 236 for engaging a recess disposed in the actuator cap body 218. The discharge orifice as shown at 239 in the front wall at 238 The recess 233a provides ample space for a swirl chamber 233 (see FIG. 9). Like the insert 132 as shown in FIG. 7, the insert 232 includes channels 241 directed toward the recess 233a and therefore the swirl chamber 233. The insert 232 also includes a heating element 243.
Turning to FIGS. 12A-12B, the insert 332 is shown equipped with a PTC resistive heating element 243 that essentially surrounds the swirl chamber 333 As liquid product passes the cross-bar 321 in the passageway 319, and proceeds past the post 331, into the swirl chamber 333, the heating element 243 heals the product flow stream thereby reducing the solubility of any compressed gas propellant in the exit stream 350 As a result, cavitation occurs, or bubbles of compressed gas propellant appear in the product flow stream thereby creating unstable thin ligaments of liquid product in the exit stream 350. The unstable thin ligaments of liquid product are then converted into small droplets having diameters of less than 35 μm. If a suitable pressure is provided within the container, and a suitable velocity is imparted to the primary droplets, the droplets will then further divide into smaller droplets by way of an atomization process.
It is believed that the cavitation process starts within the swirl chamber 333 and continues as the product flows through the discharge orifice 339 and into the exit orifice 322. A variety of different heaters can be employed, and while a simple resistance heating element may be used, a PTC heating element is preferred as it can easily maintain a constant temperature in the swirl chamber 333. Electrical leads for the heater 343 are shown at 344, 345. Examples of PTC heaters can be found in U.S. Pat. Nos. 3,927,300, 3,338,476, 4,088,269, 4,212,425, 6,220,524 and 6,501,907 See also U.S. Pat. No. 3,476,293.
Turning to FIGS. 13-19, an insert 432 is disclosed that includes a breakup bar 451. Essentially, as best seen in FIG. 19, two opposing channels 441 are disposed in the insert 432. As product travels towards the exit orifice 439, the product is directed through the oppositely directed channels 441 so the product engages the breakup bar and other product to provide highly turbulent flow before it reaches the exit orifice 439. FIG. 17 illustrates the placement of the oppositely directed channels 441 between four circumferentially spaced posts 452 which further promote turbulent swirling flow as product moves toward the exit orifice 439
In summary, an improved aerosol dispensing system is disclosed which enables a compressed gas propellant, such as carbon dioxide, to be used to deliver liquid product. Preferably, compressed gas propellant should be soluble in the liquid product at room temperature and less soluble or relatively insoluble in elevated temperatures. Thereby, the heating of the exit stream will result in cavitation or propellant bubbles emerging in the exit stream to form unstable thin ligaments These unstable thin ligaments will then be converted into droplets which preferably will have a Weber number sufficiently high so as to result in secondary atomization and even smaller droplets. In any event, the proposed designs provide an aerosol mist with a mean Sauter diameter of less than 35 μm.
While only certain embodiments have been set forth, alternatives and modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of this disclosure and the appended claims
INDUSTRIAL APPLICABILITY
An improved aerosol dispenser is provided using a compressed gas propellant free of volatile organic compounds and that includes an actuator cap equipped with a heater for reducing the particle size of the resulting mist
Patent Application
20080067262
