US1853682A - Atomizing apparatus - Google Patents

Description

April 12, 1932. HECHENBLEIKNER ATOMI Z ING APPARATUS Filed May 18, 1927 INVENTOR lngenuln Hechen He} kne BY zToRNEYs Patented Apr. 12, 1932 UNITED STATES PATENT, OFFICE INGENUIN HECHENBLEIKNER, OF CHARLOTTE,

TION OF DELAWARE u ATOMIZING APPARATUS Application filed Kay 18,

This invention relatesto improvements in atomizing or sprayingdevices, and more particularly to atomizing or spraying devices employable for the atomization of liquids, slutions or suspensoids.

As is well known, atomization of liquids and solutions is employed in the arts in various industries for producing finely divided solids or powdered substances.

,When employed for ato'mizing true or suspended solutions atomization is usually accompanied by vaporization, and where it is desired to produce a powdered substance from a liquefied state of such substance, the process is practiced without accompanying vaporization.

The improved atomizing or spraying apparatus of my present invention is generally applicable to atomizing liquids and solutions ,of various sorts in theseindus- :0 tries.

One of the objects of the present invention is to provide an atomizing or spraying device which may be applied andemployed in the atomizing and spraying of all types of liquids and for all purposes. Where the object is to obtain the finely divided, dry solid, the

atomizing or spraying is generally followed by treatment with hot or cold air. Hot air is usually used in su'ch cases where the liquid under treatment contains solids therein, either in solution or in suspension. In such cases it is necessary to evaporatethe water or other liquid and in such cases the spraying device is disposed in a large chamber through which hot air is passed for the purpose of vaporizing the liquid in the spray or mist formed in the chamber by the atomizing device and causing the precipitation of a finely divided solid.

40 the production of dry milk or the atomization of various salt solutions for the purpose of obtaining a salt in finely divided solid form.

I The present device may also be used in the formation of powdered soap and similar industries. In these processes the soap or other substance is fed to the atomizing .device in its fluid or liquid state, and is then atomized or sprayed into the chamber where it comes in contact with cold air which causes the fine- Examples of such cases are 1927. Serial No. 192,464.

1y divided particles of liquid soap to solidify and precipitate in finely divided form.

The above uses of the present device are merely cited as illustrations of the variety of uses and the variety of industries. in which the present device may beemployed, it being understood that these examples are not to be considered as limitations upon the scope of the present invention.

The prime desideratum of the present invention is to provide an atomiz'ing device which will form -a uniform fine spray or mist. Broadly, the embodiment of the invention as disclosed in this application comprises a rotating disc to which the liquid to be atomized is supplied in the' form of a flowing stream. Discs, however, have already been utilized for atomizing or spraying purposes.

that when a high de-'v It is found, however, gree of atomization is desired, such discs must be rotated at extremely high speeds. In the present invention, however, the speed of the disc is reduced to comparatively low its without interfering with the quality, ness or uniformity of the spray formed thereby. It is found that with the device that constitutes an embodiment of the present invention the range of or desirable. falls second, the speed being varied in accordance with the coarseness or fineness of the atomization desired. As will be explained hereinafter, another element may be varied together with the variation 1n speed to give variation in the size of the particles formed, and to maintain their uniformity, the other factor entering into consideration being the length of the sloping sides of the discharge partitions or fins, which will be described more fully hereinafter. 4

As a concomitant of the reduction in speed of the device is the reduction in power consumption in the-operation of the device.

Another object of the present invention is to cause the disc to cooperate with the liquid under treatment in such a manner that before the liquid is permitted to leave the periphery of the disc it has fully acquired the speed of the disc, and the centrifugal forces which enter as a factor in the atomization or spray- NORTHv CAROLINA, ASSIGNOR, BY-

peripheral speed necessary between 100-200 feet per.

ing of the liquid under treatment are utilized to the maximum capacity. The device is further so designed and constructed that this process of imparting the high speed to the liquid is not accompanied by any splashing.

The device is further so designed and constructed that in addition to the centrifugal forces for the atomization of the liquid, air pressure is utilized to aid and assist in the process of atomization. This air pressure is inherent in the construction and operation of the device which creates a substantial difference of pressure between the interior and the exterior thereof. It is understood, however, that if desired an external source of air pressure may alsobe employed to assist the pressure head created by the operation of the atomizing head. It is therefore an object of the present invention to provide an atomizing device which utilizes the centrifugal forces due to rotation as well as the atomizing effect of an air pressure head. The device is further so constructed and designed that the air is caused to intimately intermingle with the liquid prior to the departure of the liquid from the periphery of the disc.

In the operation of various spraying devices known hitherto, difficulty has been experienced due to the fact that solids are deposited on the disc with the formation of a cake which throws theentire device out of balance and thereby shortens its life and increases the power consumption. In the present device this difliculty is entirely obviated. In other types of spraying devices known hitherto other difiiculties have been experienced, due to the fact that the discharge open ings, usually of nozzle construction, clog or stop up in use by the deposit of solids in the discharge openings. This is generally due to the fact that the nozzle openings in order to obtain proper atomization, are usually made of small dimensions; and the clogging up in these small discharge openings is accentuated. by crystallization which takes place at such openings due to the hot gases surrounding the atomizing device. This objection or difiiculty inherent in prior devices is obviated by means of the present invention by the improved construction of the .spraying head which permits of comparatively large discharge openings to be used, and which further permlts the selective use of a cooling fluid which prevents and minimizes crystallizing tendencies.

Other objects and advantages of the present invention will be apparent from the description of the construction and the operation of the device. i

The manner of attaining the above objects will be apparent from the description and the drawings, in which Fig. 1 shows a drying chamber having the spray forming device of the present invention installedtherein,

Fig. 2 shows the construction of the atomizing head, and

Fig. 3 is a plan view of the atomizing head with one part partly broken away. I

In the drawings, reference numeral represents a spray drying chamber which is provided with openings 11 in its upper wall to shaft 17 of the motor 13 and is rotated thereby, the casing 15 from the head 12.

As shownin the drawings, the atomizing head 12 is of integral construction. It is obvious, however, that this is not a necessary feature of the present invention, and that, if desired, the atomizing head 12 shown herein may consist of several parts separate in form and subsequently assembled.

Specifically, the atomizing head 12 consists of the dished disc 18, the annular cover plate 19 and the fins or partitions 20 disposed in the annular space therebetween, the said fins or partitions 20 connecting said cover plate and said disk to form a peripheral wall, the said peripheral wall being provided with the plurality of peripherally disposed discharge openings '21. The side walls of the fins 2O define the side walls of the openings 21. The dished face of the disc 18 is provided centrally thereof with an upstanding hub 22 which is so shaped as to form the annular depression 23 having a curved face 24 shown in cross-section in Fig. 2. I

One of the primary constructional features of the atomizing head 12 resides in the deep 23 which serves to receive being but slightly spaced annular channel the stream of liquid 25 flowing from the feed pipe 16. The important feature of this phase of the construction is that the channel is of such a depth that it is never completely filled by the liquid under treatment and serves as an air reservoir, whose function will be described presently. Another primary phase of the construction of the present device is embodied in the fins or partitions 20. These fins or partitions, as shown, are preferably triangular in cross-section, having their apiees directed towards the center of the disc. The sidewalls" of each of the fins 20 thus slope inwardly (relatively to a disc radius common to the side walls) and towards each other; and the said fins extend inwardly or radially from the periphery of the disc only a short distance so that they are substantially localized at the periphery of the disc; In the operation of the apparatus these fins or partitions act as the blades of a fan and cause a suction of the air lodged in the annular channel 23 and thereby bring about an air pressure head between the inner and outer ends of the discharge openings. This causes an intimate intermingling between the air and the liquid under treatment-to take place within the discharge opening which aids and assists materially in the atomization of the liquid. The size and shape of the fins or partitions may be varied with the variation in the speed of operation of the apparatus. The lower the speed of rotation of the atomizing head, the greater the radial dimension of the fins or partitions-and the smaller the slope of the sides of the fins or partitions.

As pointed out above, the annular channel 23 serves as a pocket for the lodgment of air which is drawn by the fan action of the fins or blades 20 upwardly and outwardly in such a manner that the air intermingles thoroughly with the liquid in the discharge openings and thereby aids in the atomization of the liquid. It should be noted at this point that the disc 18 and the cover 19 are provided with annular horizontal faces 26 and 2'? respectively whose radial dimension is the same as the radial dimension of the fins or partitions 20 and serve as the upper and lower walls for the discharge openings. The annular channel 23, in additionto serving as a chamher for the lodgment of air, also serves to receive the liquid, the face 24 of the channel 23 being so shaped that the liquid entering from the pipe 16 andfed in the manner shown against the hub 22 will join the surface of the rotating disc in such a manner that the liquid' will not splash. Furthermore, the upward slope 28 of the operating face of the disc forces the liquid to flow upwardly with a rotation of the disc, thus preventing thesplashing of the liquid and also causing the liquid to'acquire the speed of the disc, so that by the time the liquid will have reached the inner end of the discharge openings 21, the liquid will have acquired the speed of the disc and the centrifugal forces resulting therefrom are fully utilized for the atomization of the liquid.

The air that is permitted to enter the spray head, as indicated by thearrows 29, may be hot air or cold air as desired and depending upon the circumstances under which the anparatus is employed and depending upon the type of material, and the treatment and the type of operation for which'the apparatus is employed.

In such cases where it is desired to evaporate solutions to produce powdered products, as for example-in the production of dried milk and in the vaporization of salt solutions for the purpose of producing a salt in powder form, cold air isdrawn into the spray head,

as indicated by the arrows 29. In the conduct of such processes hot air is drawn through the drying'chamber 10 with the consequence that with the use of apparatus known hitherto, the spraying disc was heated and it frequently happened that solid material was caked on the operating face of the disc and some of the solids deposited within the discharge openings. By the use of cold air in the present apparatus, the disc, the metal immediately adjacent the dischargeopenings, as well as the liquid, while it is within the atomizer head, is cooled, and crystallization at this point is thereby prevented.

' On the other hand, in the treatment of liqiud soap, namely soap in the hot and fluid state, for the production of dry powdered soap, or in other similar processes, hot air may be drawn into the atomizer head along the path indicated by the arrows 29. In

such processes cold air is passed through thedrying chamber as indicated by the arrows 30, the object being to reduce the temperature of the hot fiuid, finely divided soap in the chamber and thereby cause the solidification thereof. The danger under such conditions is that the cold air may cause the solidification of the fluid soap at the discharge openings. In order to prevent this difiiculty from arising, hot air is drawn into the atomizing head so that the fluid is maintained at the temperature above solidification as long as it remains within the atomizing head.

When'the apparatus disclosed herein is employed to separate solid particles which are suspended in the liquid, either hot or cold air may be drawn through the atomizer as desired, for in-such case the problems and difficultieswhich have been pointed out above "do not arise, the function of the air in such instances being limited to its assistance in the atomization of the liquid so as to facilitate the vaporization thereof and increase the efiiciency of the entire system.

It is to be understood that whether hot or cold air is drawn through the atomizer head, the amount of such air is small as compared with the amount of air that passes through the drying'chamber and will not materially affect the process of vaporization or solidification that takes place within the chamber 10.

Under some conditions it may be desirable to drawthe atomizer air through the motor casing so that the air is preheated, the air also serving to cool the motor.

The upward and outward slope of the operating face of the disc 18 also cooperates with the downwardly and outwardly sloping 'lid 19 to confine the flow of air along the path indicated by the arrows 29 and direct same towards the discharge openings 21, and thereby cooperate with the operation'of the fins or partitions 20 to bring aboutthe air pr'essure head between the two ends of the discharge openings.

It should also be noted at this point that while the air drawn through the discharge openings is thoroughly intermingeld with the liquid flowing through said openings in the annular space formed by the faces 26 and 27, the air passes out of said openings as indicated by the arrows 30 and further serves to increase the atomization of the liquid at points immediately adjacent to the periphery of the device due to the velocity of the air as acquired in passing through the discharge openings.

In one embodiment of the present invention, the disc 18 has a maximum diameter of 9", which when rotated gives a peripheral velocity varying from 100 feet per second to 200 feet per second. In this form of the device, the partitions or fins 20 have. a radial depth of of an inch and their widest dimension is of an inch. When this embodiment of the invention is rotated at a speed to give a peripheral velocity of 150 feet a second, the resulting spray is of a high degree of subdivision and uniform in nature. The finenesS of the particles obtained may be varied by varying the velocity of the rotation of the device. The slower the velocity the coarser the particles. In order to obtain the same high degree of uniformity, it is preferable that when the machine is designed for reduced velocities, the radial depth of the fins should be increased and the slopes of the sides thereof should be decreased. Highly uniform results, however, are obtained by varying the velocity of the same apparatus without necessarily varying the depth in slope of the fins.

It will also be apparent that while I have shown and described my invention in the preferred form, many changes and modifications may be made in the structure disclosed without departing from the spirit of the invention, defined in the following claims.

I claim:

1. In an atomizing device, a rotatable disc having a hub disposed centrally thereof and on its operating face, and having a relatively deep annular channel surrounding said hub, means for feeding liquid to said channel tangentially of its face, anda plurality of triangularly shaped fins arranged around and localized at the periphery of said head and spaced peripherally, to define discharge openings for said channel, the apices of said fins being directed inwardly. l

2. In an atomizing device, a rotatable disc, a lid for said disc and spaced therefrom and a plurality of partitions connecting the peripheries of said lid and said disc and dividing the space between said lid and said disc into a plurality of discharge openings, each partition having its lateral walls sloping inwardiy and toward each other.

3. 11 an atomizing device, a rotatable disc havin an upwardly sloping operatin face, 7

a lid t erefor spaced from said discan sloping outwardly and downwardly forming an annular space with said disc, discharge partitions disposed in said annular space. and having sloping sides localized at the periphery of said disc, the slope of the sides being so related to the speed of operation of the device that a uniform spray of a predetermined degree of fineness is formed thereby.

4. An-atomizing apparatus comprising a rotatable atomizing head having a charge opening and having a peripheral wall provided with peripherally arranged comparatively large discharge openings, the said head having a relatively deep annular channel having an operating face sloping upwardly toward the periphery of said head, and laterally arranged fins having sloping side walls embodied in said rotatable head and localized at the periphery thereof.

5. In an atomizing head, a rotatable disc, means for feeding hquid to said disc, a lid disposed over said disc and spaced therefrom to form an unobstructed annular space, said lid having an opening therein, and substantially radially arrange partitions localized at the periphery of said ead connecting said lid and said disc to form a peripheral wall, said wall having a plurality of peripherally disposed discharge openings.

6. An atomizing device comprising a rotatable disk-shaped head, said head being provided with a plurality of triangularly shaped fins arranged around and localized at the periphery of said head and spaced peripherally'to define discharge openings therebetween, the apices of said fins being directed inwardl 7. An atomizing device comprising a rotat'able head, said head being providedwith a plurality of peripherally arranged partitions, said partitions dividing the peripheral space of said head into a plurality of discharge openings, each partition having its lateral walls sloping inwardly and toward each other.

8. An atomizing device comprising a rotatable disk-shaped head, discharge parti-' tions disposed in and localized at the peripheral space of said head, said partitions having sloping sides, the slope of the sides of said partitions being so related to the speed of operation of the device that a uniform spray of a predetermined degree of fineness is produced in the operation of the device.

9. An atomizing device comprising a rotatable head, said headbeing provided with substantially I radiall arranged partitions localized at the perip cry of said head, saidpartitions forming a peripheral wall, said peripheral wall having a pluralityof peripherallydisposed discharge openings.

10. An atomizing device comprising a rotatable head, partitions disposed in the petoo ripheralspace of said head, the spaces between said partitions definin discharge openings and the side Walls of said partitions forming the side walls of said openings, the adjacent side walls of contiguonsly arranged partitions being directed relatively to each other so as to define converging discharge openings.

Signed at Charlotte, in the county of Mecklenburg, and State of North Carolina,

this 16th day of May A. D. 1927.

INGENUIN HECHENBLEIKNER.

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