USP_20090224066_Ultrasonic atomizing nozzle methods for the food industry_VIP (1063672), страница 3
Текст из файла (страница 3)
This reduces the likelihood that eitherthe rear horn 12 or the front horn 16 Will crack as threadedholes are formed therein or that the ceramic threads formed insuch holes Will lack the shear strength to sustain the amountsof pressure to Which they may be subjected (e.g., over 10,000psi).[0037]Also illustrated in FIG. 1 are a front shroud 11, a rearshroud 13 and a plurality of O-rings 15. Together, the front[0038]FIG.
2 illustrates a radial cross-section of the ultrahas a ?uid inlet 28 at the center thereof. This ?uid inlet 28 ispart of the liquid conduit 30 illustrated in FIG. 1 that alloWsliquid to travel from the liquid inlet 14 all the Way to theatomizing surface 20 on the front horn 16.[0039] As also illustrated in FIG. 2, the ring 24 extendsaround the rear horn 12 and has a plurality of bolts 26 positioned at various locations about the circumference thereof.Although a ring 24 is illustrated in FIG.
2 as making up aportion of the above-discussed clamp, other components maybe positioned adjacent to the ?anges 22 illustrated in FIG. 1.For example, square or rectangular plates may be used. Also,although six regularly spaced bolts 26 are illustrated aroundthe periphery of the ring 24 in FIG.
2, other distributions ofone or more bolts 26 or other fasteners may be used accordingto other embodiments of the present invention.[0040] FIG. 3 is a longitudinal cross-sectional vieW of anultrasonic atomizing nozzle arrangement 32 according to asecond embodiment of the present invention. Like the nozzle10 illustrated in FIG. 1, the nozzle 32 illustrated in FIG. 3includes a liquid inlet 34, a rear horn 36 and a front horn 38,each having a ?ange 40.
The front horn 38 also includes anatomizing surface 42 that is positioned at one end of a liquidconduit 44. In addition, the nozzle 32 illustrated in FIG. 3includes a clamp arrangement that includes a plurality ofrings 46 and bolts 48. Further, the nozzle 32 also includes atransducer portion 49 that includes a pair of transducers thatare positioned in an intermediate section of the nozzle 32 thatis located betWeen the rear horn 3 6 and the front horn 38. Alsoillustrated in FIG.
3 are a front shroud 33 and a rear shroud 35that, together, provide a housing for the nozzle 32 and aplurality of O-rings 37 that provide a plurality of seals Withinthis housing.[0041] One Way in Which the nozzle 32 illustrated in FIG. 3differs from the nozzle 10 illustrated in FIG. 1 is that the fronthorn 38 illustrated in FIG. 3 is approximately 3 times a longas the rear horn 36 illustrated therein. This is particularlyrepresentative of the fact that the rear horn 12 and front horn16 may, according to certain embodiments of the presentinvention, have different lengths. In fact, according to certainother embodiments of the present invention, the respectivelengths of the rear horn and front horn in a given nozzle aremultiples or fractions of each other.
As mentioned above,under certain operating conditions (e.g., high frequencies), itbecomes impractical to manufacture horns having lengthsequal to M4. Therefore, horns having lengths equal to multiples of M 4 are often used under such circumstances.[0042] FIG. 4 and FIG. 5 illustrate a controllable ultrasonicsprayer 80 according to a third embodiment of the presentinvention. A ?at jet air de?ector horn 82 is positioned adjacentto an atomizing surface 89 of an ultrasonic nozzle 85. The ?atjet air de?ector horn 82 and atomizing surface 89 are eachlocated on a jet block assembly 87. The ultrasonic nozzle 85may be made from titanium and 316 stainless steel making itnon-reactive With most liquids, although other types of materials may also be used.
An air inlet ?tting 81 and a liquid inlet?tting 83 are also situated on jet block assembly 87.[0043] In operation, a controllable source of air is attachedto air inlet ?tting 81 and liquid to be atomized is connected toSep. 10, 2009US 2009/0224066 Althe liquid inlet ?tting 83 . A controllable air stream 84 from the[0051]air inlet ?tting 81 is sent towards the ?at jet air de?ector horn82, Which reshapes the controllable air stream 84 into a ?attened air pattern 86.
The ?attened air is de?ected toWard theatomiZing surface 89 of the ultrasonic noZZle 85. Liquid thatentered the sprayer 80 through the liquid inlet ?tting 83 isatomized by the ultrasonic noZZle 85 and output at the atomiZing surface 89. The atomiZed liquid is entrained in the?attened air pattern 86 producing a fan pattern 88 that is(i.e., vibrating) the surface at an ultrasonic frequency.According to certain embodiments of the present invention,this mechanically moving step includes mechanically moving the surface at a frequency of betWeen approximately 120kHZ and approximately 250 kHZ.
According to other embodicomposed of air and the atomiZed liquid.[0044]The area of the fan pattern 88 as Well as the velocityand impact force of the atomiZed liquid particulate is relatedto the velocity of the controllable air stream 84. The ultrasonicnoZZle 85 may operate in, for example, a frequency range of25-120 kHZ alloWing for a variety of drop siZes With a ?oWThe method also includes mechanically movingments of the present invention, the mechanically moving stepincludes mechanically moving the surface at a frequency ofbetWeen approximately 25 kHZ and less than approximately120 kHZ (e. g., approximately 60 kHZ).[0052] The above-discussed method also includes formingdrops of the liquid having number median drop siZes of lessthan approximately 20 microns.
According to certainembodiments of the present invention, the coating step comprises selecting liquids containing an organic solvent.rate from 1 ml/minute to 99 ml/minute.[0045] FIG. 6 is a side vieW of an ultrasonic vortex noZZlearrangement 50 according to a fourth embodiment of theAccording to these embodiments, the number median dropsiZe of the drops formed during the above-discussed formingstep is betWeen approximately 7 microns and approximatelypresent invention. The arrangement 50 includes a liquid inlet10 microns.?tting 52 through Which liquid enters the noZZle.
Also[0053]included is an input connector 54 from a broadband ultrasonicthe liquid through an interface section that includes a ceramicThe above-discussed method also includes passinggenerator (not illustrated). The input connector 54 conveysmaterial before performing the coating step. This passing stepultrasonic vibrations from the generator into components ofthe arrangement 50 (i.e., the connector 54 causes certaincomponents of the arrangement 50 to vibrate back and forth atan ultrasonic frequency).may be performed, for example, by passing liquid through[0046]Also included in the arrangement 50 are a noZZlestem 56 through Which liquid in the arrangement 50 issprayed and a noZZle body 58 that supports the stem 56.
Theeither the rear horn 12 or the front horn 16 illustrated in FIG.1, so long as at least one of these horn 12, 16 has a ceramicmaterial incorporated therein.[0054] According to other embodiments of the presentinvention, the above-discussed method includes clamping thenoZZle stem 56 and body 58 are included Within a noZZleinterface section to an atomiZing section that includes theceramic surface. This clamping step is typically an alternativehousing 60 to Which is also connected the liquid inlet ?ttingto having to use fasteners that Would have to be screWed52 and the input connector 54.[0047] A compressed air inlet 62 is also connected to thehousing 60. This inlet 62 is used to introduce compressed airinto the arrangement 50 and the compressed air is output fromthe arrangement 50 through tWo compressed air outlets 64located adjacent to the noZZle stem 56.
In operation, loWvelocity rotational air is expelled from the air outlets 64 toproduce a Wide and stable spray pattern of liquid from thedirectly into components of a noZZle used to implement theabove-discussed method.[0055] According to certain embodiments of the presentnoZZle stem 56.[0048] According to certain embodiments of the presentinvention, the arrangement 50 produces a conical spray pattern 68 that is betWeen approximately 2" and approximately6" in diameter, depending upon the frequency used and theinvention, the above-discussed atomiZing noZZle arrangements 10 are con?gured to be used in the food industry andare operated in a manner consistent thereWith. For example,according to certain embodiments of the present invention, afoodstuff and/or a food packaging material is coated utiliZingthe above-discussed atomiZing noZZle arrangements 10 in anultrasonic spraying process.being sprayed/ coated.
For example, a 25 kHZ frequency Will[0056] FIG. 7 illustrates a perspective vieW of a food coater66 according to an embodiment of the present invention. Thefood coater 66 includes a plurality of noZZle arrangements 10located Within a chamber 68. Extending through the chamber68 is a conveyor belt 70 upon Which is positioned a foodstuffproduce a mean Water drop siZe of 70 microns and the fre72. Also, operably connected to and positioned external to thequencies of 35 kHZ, 48 kHZ, 60 kHZ and 120 kHZ Will produce 49 micron, 38 micron, 41 micron and 18 mean micronchamber 68 is a control system 74.distance betWeen the noZZle stem 56 and the surface/itemsiZe Water drops, respectfully.[0049]As Will be appreciated by those of skill in the art[0057] The control system 74 illustrated in FIG. 7, according to certain embodiments of the present invention, is comupon practicing one or more embodiments of the presentputeriZed and connected to at least one of the noZZle arrangements 1 0 and the conveyor belt 70.
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