US3458948A - Apparatus for producing an aerosol - Google Patents

Description

APPARATUS FOR PRODUCING AN AEROSOL Aug. 5, 1969 R R' CURT'S ET 3,458,948

Filed July 7, 1967 v L" l' O 1o w3 Hu /m 556 n 65 Fig. 3 C

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Fig. 6 |5 |09 ALBERT' L. SCHLEMSKER O Flg. 4km, JAMES E Jwva United States Patent O U.S. Cl. 43-129 7 `Claims ABSTRACT OF THE DISCLOSURE A fog producing apparatus of the portable type having a heat exchanger, having excellent thermal efficiency, which is readily disassembled for cleaning without dismantling the fog producing apparatus.

Portions of the apparatus herein disclosed are disclosed and claimed in our copending patent application Ser. No. 651,838, led July 7, 1967 assigned to the as signee of the present application.

BACKGROUND OF THE INVENTION Field f the invention The apparatus of the invention, commonly called a fogger, is ideally suited for dispensing minute droplets of insecticides onto plants, shrubbery and the like. It is to be understood, however, that the apparatus may be used for dispensing liquids other than insecticides. The housing encloses a heat exchanger connected to a nozzle and also supports a motor driven pump which receives liquid from the reservoir and produces a pressurized flow of liquid through the heat exchanger for discharge from the nozzle. It has been found that many liquid insecticides contain a heat sensitive substance or chemical which produces, when heated, a film-like coating on the inner wall surface forming the passageway through the heat exchanger. After intermittent operation of the fogger over a period of time, the coat will build up to form a hardened layer or deposit lining the passageway. This coating not only results in reducing the heat transfer efficiency of the heat exchanger but occasionally will iiake off in the form of small particles which are of suliicient size to clog the nozzle or orifice.

SUMMARY OF THE INVENTION The apparatus of the present invention has an improved heat exchanger including a body in which a core is removably mounted for conveniently cleaning the liquid passageway through the heat exchanger; the passageway for fluid is cooperatively dened by the body and the core in such a manner as to provide for efficient and uniform heat transfer to the liquid flowing through the passageway, the mounting for the core serving as the puller for conveniently removing the core from the body of the heat exchanger when it is desired to clean the passageway through the heat exchanger.

BRIEF DESCRIPTION OF THE DRAWING The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

FIG. 1 is an elevational View of a fogger constructed in accordance with the invention and with a portion shown in section to show generally the internal arrangement of the major components;

FIG. 2 is an elevational view of the forward end portion of the fogger as generally taken along the line 2 2 of FIG. 1;

FIG. 3 is a view of the heat exchanger as taken along the line 3-3 of FIG. 1;

3,458,948 Patented Aug. 5, 1969 ice DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing which illustrates a preferred embodiment of the invention, FIG. 1 shows a fogging apparatus constructed in accordance with the invention and including a housing 10 adapted to be formed as a plastic molding in two half sections and with a generally uniform wall thickness. The housing 10 basically includes a hollow forward portion 11, a hollow handle portion 12 and a rear bottom portion 13. A perforated plate 15 having holes 14 formed therein forms the forward end wall of the housing portion 11. Apertures 16 are formed within the bottom portion 13 of the housing adjacent a downwardly projecting cylindrical boss 17 formed with internal threads. A cylindrical container 20 defining a liquid reservoir 22, includes a neck portion 23 which is threadably received within the boss 17 for convenient removal.

A pump 25 is mounted on the bottom portion 13 of the housing 10 by a tubular support member 27 so that the pump is suspended within the reservoir 22. The specific construction of the pump 25, however, forms no part of the present invention, and it is to be understood that any pump system may be employed. In general, however, the pump 25 includes a screened inlet member 29 which is positioned adjacent the bottom of the container 20. Preferably the pump is of the positive displacement type and includes a piston (not shown) which is reciprocated through a connecting rod 32 eccentrically connected to the shaft of an electric motor 34. An axial flow fan blade 35 is also mounted on the shaft of the motor 34 for pulling cooling air in through the holes 16 and dischanges the air through the housing 10 and out of the holes 14.

The pump 25 has an outlet which opens to passageway within a conduit 37 connected to the pump. 'I'he ow through the conduit 37 from the pump 25 is controlled by an actuating rod 38 which extends upwardly from the pump through the housing 10 to receive a push button 40 retained within the handle portion 12 of the housing 10. The push button 40 and actuating rod 38 are normally baised upwardly by a compression spring 41 retained within the handle 12. The maximum flow of liquid through the conduit 37 is determined by a stop member 43 surrounding the upper portion actuating rod 38. The stop member is adjustable by manually turning a flow control knob 44 threadably received within the handle portion 12 of the housing.

An elongated heat exchanger 45 including a body 46, is supported, at its inner end within the housing 10 by a plate 47 which extends across the housing and is retained by slotted sockets 48 on the housing sides. The front end of the housing is supported by plate 15 as will subsequently be described. Referring to FIG. 3, a pair of electrical heating elements 50 are mounted within the body 46 of the heat exchanger 45, the heating elements being electrically connected together at their outer or forward ends and form terminal lportions 54 which are suitably connected through a thermostat 56 (FIG. 1) to an electrical power supply. As shown in FIG. 1, the thermostat 56 is mounted on a ilat upper surface formed on the heat exchanger 45 so that the' thermostat directly senses the temperature of the body 46 adjacent the discharge end of the heat exchanger.

An elongated tapering opening of circular cross-section is defined within the body 46 by a smooth tapering surface 60 (FIG. 3). A smaller concentric opening 62 is formed within the inner end portion of the body 46 for receiving theI fitting 59 which communicates with con duit 37.

Referring to FIG. 4, the forward end portion of the body 46 is provided with upper and lower extending flange portions 65 in which are formed corresponding threaded holes 66. An oval-shaped boss 68 projects from the forward surface of the flange portions 65 and is received within a corresponding shaped opening 69 (FIG. 2) formed in the plate 15.

An elongated core 70 (FIG. 3) is mounted within the opening formed within the body 46 and includes an outer surface 72 having a taper which mates with the taper of the internal surface 60 defining the central opening in body 46. As shown in FIG. 3, a helical groove 75 is formed within the tapering surface 72 of the core 70 and cooperates with the surface 60 to define a helical passageway 77 communicating, through an axial groove in the end portion of the core and then through fitting 59, with conduit 37.

The forward end of the helical passageway 77 is connected, by passage 83, to an axially extending passageway 80 (FIG. 4) formed within the forward end portion 82 of the core 70. A threaded boss 84 projects from the forward end portion 82 of the core 70 and a nozzle member 85 having an orifice housing 88. A discharge opening 90 is formed within the -forward end portion of the nozzle housing 88 and in alignment with the orifice 86. Air receiving ports 92 are formed within the nozzle housing 88 surrounding the nozzle orifice 86.

The forward end portion 82 of the core 70 is provided with a cylindrical external surface which is somewhat smaller than the diameter of the internal surface 60 of the body 46 and thereby forms an annular shoulder 97 (FIG. 4) which is spaced inwardly, within the bore or opening, from the forward end faceI of the heat exchanger body. A resilient seal or packing member 98 surrounds the core and is positioned against the shoulder 97. A cylindrical sleeve 100 is mounted on the forward end portion 82 of the core 70 and is positioned in 4front of the packing 98 so that the forward end surface of the sleeve projects slightly from the end surface of the boss 68.

The retaining plate 105 (FIG. 5) includes a central opening for receiving the forward end portion 82 of the core 70 and is spaced between the sleeve 100 and the rear surface of the nozzle retaining housing 88. The plate 105 is formed downwardly along opposite sides to form parallel flanges 107 (FIG. 5) which strengthen the plate 105 and are spaced adjacent the core end portion 82 to engage the forward end surface of the sleeve 100.

Slots 109 (FIG. 5) are formed on opposite ends of the plate 105 and are aligned with the threaded holes 66 formed within the flanges 65 and corresponding aligne-d holes formed within the forward end wall 15 of the housing portion 11 for knurl-headed screws 110. Annular flanges 112 are formed on the screws 110 and the flanges are spaced from the head of the screws 110 for receiving the slotted end portions of the plate 105 therebetween.

As shown in FIG. 3, the forward end portion 82 of the core 70 is provided with opposing flat surfaces 115 and correspondingly intertting flat surfaces are formed on the plate 105 to assure that the core 70 is maintained in proper alignment within the body opening 59.

In operation, when the electrical heating elements 50 are energized, the indicating light 116 (FIG. 1) is also energized. When the heat exchanger body 46 reaches a predetermined temperature, the thermostat 56 opens the electrical circuit to the heating elements and deene-rgizes the indicating light 116 to indicate that fogger is ready for use. In a manner described in the copending patent application mentioned supra, liquid from the reservoir 22 is supplied to the heat exchanger through the conduit 37 by depressing the push button 40. The liquid travels through the heat exchanger 45 within the helical formed passageway 77 so that when the heated, pressurized liquid is discharged through the nozzle orifice 86, the liquid immediately vaporizes and the vapor mixes with the cooler atmospheric air flowing in through the ports 92 and the vapor condenses to produce a fog.

After the fogger has been used for an extended period of time and it is desirable to clean the surfaces defining t-he helical passageway 77 within the heat exchanger 45, the core 70 can be conveniently removed simply 'by unthreading the screws 110. This causes the screw flange 112 to engage the retaining plate 105 whi-ch, in turn, engages the nozzle housing 88 so that the core 70 is extracted from the taper opening. With the core removed, the spiral groove 75 and the internal surface 60 can be conveniently cleaned with, for example, suitable wire brushes.

After the scale or hardened deposit has been removed from the core 70 and lbody surface 60, the core is reinserted within the opening 59 and the screws 110 are rethreaded into the corresponding openings 66. Tightening of the screws causes the flanges 107 of the plate 105 to exert an axial force on the sleeve and thereby compress the packing and seal member 98 against the core shoulder 97 to form a tight seal between the end portion 82 of the core 70 and the internal surface 60 of the body 46. The axial force also provides a firm contact between the outer surface 72 of the core 70 and the internal tapered bore 60 of the body.

From the drawing and the above description, it can be seen that fogger const-ructed in accordance with the invention provides several desirable features and advantages. For example, by constructing the heat exchanger 45 with a conveniently removable core 70, any deposit which forms or carbonizes on the surfaces which define the passageway 77 can be conveniently and easily Iremoved when desired to assure that the fogger operates at maximum efliciency. The mating tapering surfaces 60 and 72 also provides for a tight contact between the core 70 and housing 46 to provide for efficient heat transfer from the body to the core. Furthermore, the heating of the liquid within the helical passageway 77 has been found to provide uniform heat transfer from the heat exchanger to the liquid and thereby assure that the liquid is discharged at a substantially uniform temperature.

Another important feature is provided by the construction and arrangement of the forward end portion of the heat exchanger including the spacing and the positioning of the plate between the sleeve 100 and nozzle retaining housing 88. That is, the plate 105 in conjunction with the screws not only provide means for clamping and sealing the Icore 70 within the body 46, but also provides for convenient but forceful removal of the core 70 when it is desirable to clean the helical grooves 75 and surface 60 defining the liquid flow passageway 77 through the heat exchanger.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.

The invention claimed is:

1. In an apparatus for producing a fog, including a housing having a reservoir for holding liquid to be dispensed as a fog, a discharge nozzle from which vaporized liquid is discharged, and means for withdrawing liquid from the reservoir; the improvement comprising a heat exchanger connected to receive liquid from said supply means and having an outlet connected to said nozzle, said heat exchanger including a hollow body defining an opening 'which is connected to receive the liquid from said supply means and providing one surface of a vaporizing passageway in said heat exchanger, a core member mounted within said opening and cooperating therewith providing the remaining surface of said passageway, an electrical heating element mounted in heating exchange relationship in said body, and means adjacent the nozzle releasably securing and mounting said core in said opening providing means for removal of the core for cleaning of the surface forming said passageway.

2. Apparatus as defined in claim 1 wherein said body is mounted in spaced relation to the walls of said housing and is substantially elongated in the direction of said opening, and wherein said core is likewise elongated to fill said opening and the cooperating passageway defining surfaces of said body and said core are constructed and arranged to define a passageway through which liquid is directed over a distance substantially longer than the length of said body.

3. Apparatus as defined in claim 2 wherein said means forming the outer surface of said core includes means defining a helical groove formed therein along the length of said core for providing uniform rapid heat transfer from said electrical heating element means and said body to the liquid flowing within said groove and for providing convenient cleaning of said groove when said core is removed.

4. Apparatus as defined in claim 3 wherein said opening and said core are formed with mating tapers, and said securing means include means for clamping said core longitudinally within said opening to provide a tight contact between the outer surface of said core and said surface means defining said opening within said body for providing efiicient heat transfer to said core and to conne the liquid within said groove.

5. Apparatus as defined in claim 4 wherein said clamping means for said core includes means for pulling the core from said tapered opening to provide for convenient removal of said core from said heat exchanger.

6. Apparatus as defined in claim 3 wherein said core includes a discharge end portion extending from the end of said body, means for mounting said nozzle on said end portion, means forming an annular external shoulder on said end portion and positioned within said opening, a ring seal surrounding said end portion and engaging said surface means defining said opening, an annular sleeve surrounding said end portion, and clamp means for applying an axial force against said sleeve to deform said seal for preventing liquid from flowing between said end portion of said core and said surface means defining said opening within said body.

7. Apparatus as defined in claim 6 wherein said clamp means include a plate mounted on said end portion of said core and located between said sleeve and said nozzle, screw means extending through said plate and threadedly engaging said body for drawing said plate against said sleeve to compress said seal, and means on said screw means for engaging said plate when said screw means are turned in the opposite direction for pulling said core from said opening.

References Cited UNITED STATES PATENTS 3,134,191 5/1964 Davis 43-129 3,229,409 l/ 1966 Johnson 43--129 3,242,098 3/ 1966 Andrews 252-359 3,255,967 6/1966 Kenney 239-133 3,392,479 7/ 1968 Simmons 43-129 ALDRICH F. MEDBERY, Primary Examiner

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