US2167233A

US2167233A - Irradiating device

Info

Publication number: US2167233A
Application number: US51578A
Authority: US
Inventors: Merrill J Dorcas
Original assignee: Union Carbide and Carbon Corp
Current assignee: Union Carbide Corp
Priority date: 1935-11-26
Filing date: 1935-11-26
Publication date: 1939-07-25
Anticipated expiration: 1956-07-25

Description

July 25, 1939. M. J; DHORCAS I 2,167,233-

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' Fild Nov. 26, 1935 Wu J $52K? FIG..3

ATTORNEY Patented July 25, 1939 UNITED STATES ATENT OFFEQE IRRADIATING DEVICE Application November 26, 1935, Serial No. 51,578

11 Claims.

This invention relates to a device for irradiating liquids or granular material with radiant energy. It is especially adapted for use in treat- .ing liquids with so-called ultra-violet energy, but 15 it is capable of use with other types of radiant energy without substantial modification. When liquids or flowing granular material is exposed to energy it is advantageously exposed in thin sheets. In the case of liquids these sheets are so thin that they are frequently spoken of as .films. In some cases it is desired to have a thin evenly flowing film. In other cases it is desirable to have a certain turbulence in the liquid or in ,the sheet of granular material during the exposure to irradiation. This application relates to the second type of apparatus and it is an object of this invention to produce a device for promoting turbulence in the liquids during exposure to irradiation. Another object of this invention is to produce a device which will secure the maximum effect upon the material being treated from a given source of radiant energy and which will be simple, efficient and economical in operation. Other objects of my invention will in part be ..evident and will in part appear later in the specification. a For a fuller understanding of my invention reference is made to the following description having reference to the accompanying drawing, in which Figure 1 is a perspective View of a'device illustrating one embodiment of my invention.

Figure 2 is an enlarged detail of a portion of the screen constituting a part of the device shown in Fig. 1.

Figure 3 is a cross section taken on line 33 of Fig. 2.

Figures 4 and 5 are diagrammatic views showing portions of screens in accordance with modifications constituting further embodiments of my invention.

During the treatment of substances with radiant energy it is desirable that each particle of the substances be subject at some time to the radiant energy without the interposition of other .particles of the substance. In some cases the substance may be opaque or only partially transparent. Moreover, certain substances which are transparent to ordinary light absorb or other wise cut off a considerable portion of the radiant energy of other wave lengths. Thus in case the radiant energy is of the type known as ultraviolet radiation it is very desirable that all portions of the substance come to the surface at some period of the irradiation. In case the substance being irradiated is not a liquid, but is a granular or pulverulent material, this is especially important. Accordingly, I have provided means for treating substances which will flow in such manner as to insure that all particles are at the exposed surface during some period of the irradiation. While I shall in this specification refer specifically to liquids it is to be understood that the process is susceptible to use in conjunc tion with the treatment of small particles of solids which will fiow under the influence of gravity.

Although in some cases it is desirable to secure the treatment of all particles by the use of a very thin film having a non-turbulent flow yet in other cases it is desirable to use a thicker film and to provide turbulence of the film or layer of the material being irradiated. In order to obtain this turbulence I have found it desirable to provide the screen or surface over which the film or layer of liquid or granular material is treated with a plurality of small corrugations or baffles set at substantial angles to each other and to the direction of flow of liquid. The provision of a screen or surface is not objectionable since in most processes of irradiation it is desirable to have the substance being irradiated flow over such a surface. I am aware that it has been proposed to use a corrugated surface or baffies on such a surface. However, these baflies 0 or corrugations are relatively large and are generally parallel and extend horizontally across the entire screen or surface. In carrying out my invention the corrugations or bailles are relatively small and do not extend across the entire surface without a break. In my preferred form the arrangement of baflles is such as to resemble in gross appearance the so-called herring-bone weave in textiles.

In the embodiment illustrated in Figs. 1, 2, and 3 there is shown a form of my invention which is designed to obtain this desirable turbulence. A screen iii is provided which is so located as to receive the radiant energy from any convenient source. This source, when it is desired that the -45 energy shall be of the ultra-violet type, would preferably be an arc lamp using impregnated carbon electrodes. However. various other sources of energy, such for example as the mercury vapor arc, may be employed. The arrange- 50 ment of the screen with respect to the are or other source of energy is well known in the art and forms no part of the present invention. Accordingly, the source of energy is not illustrated in the drawing. A screen Ii) is provided with 65 suitable means for distributing the liquid or finely divided solids to be irradiated along the top of the screen. The material being irradiated then flows under the influence of gravity along the screen. Various types of distributing means may be employed such as a trough ll having a plurality of slits in the bottom or such a device as is shown in the copending application of Supplee and Dorcas, Serial No. 690,411, filed September 21, 1933. The screen is provided with a plurality of corrugations. These are shown more in detail in Figs. 2 and 3. The corrugations are not extremely large and are arranged in such a manner that the relative motions of the particles of the substance being irradiated are changed. I have found the arrangement shown in Figs. 2 and 3 particularly advantageous. Such an arrangement may Well be characterized by the term zig zag and it resembles in appearance the weave known as herringbone in the textile art. These corrugations, which are designated as l2 in the drawing, produce a tumbling effect giving rise to a turbulence such that during a passage of the liquid down a screen each particle will at some time be exposed to the radiant energy without the interposition of any other portion of the substance being irradiated. The term screen as used herein would generally apply to an opaque screen with the source of energy on the same side of the screen as the substance being treated. However, it is within the scope of my invention to use a screen transparent to the radiant energy with the source of energy on the side of the screen opposite to the substance being treated.

While I have indicated that the corrugations may well cover the entire surface of the screen it is not imperative that they do so in all cases. However, I have found it advantageous in most cases to provide means such that the turbulence and consequent rotation of the particles of the substance being irradiated takes place without substantial intervals of quiet flow. While I have used the term corrugations it is of course im material whether the entire body of the screen be deformed. In the drawing I have shown a construction in which a sheet metal screen is employed and the entire sheet of metal is so deformed. However, it is possible to have a screen which is provided with a surface made in accordance with my invention and another surface which may be plain or of any desired form. Ordinarily the corrugations would be integral with the main body of the screen but it is within the scope of my invention to use bafiles secured thereto by welding, rivets, or otherwise. The baffles or corrugations may be angular or rounded in cross section and the term zig zag is intended to include a sinuous grooved arrangement as well as the angular arrangement shown in the drawmg.

In some cases it may be desirable to have corrugations of different size superposed one on the other. Thus in Figs. i and 5 I show a portion of a screen in which corrugations of different sizes are employed. In the particular modification shown the screen is provided with relatively large curved corrugations extending in parallel horizontal arrangement. superposed on portions of these corrugations and preferably on the crest and trough portions thereof are a plurality of relatively small corrugations l22 of angular cross section. These superposed corrugations are inclined to the horizontal and to the vertical. Ordinarily the inclinations of adjacent superposed been somewhat exaggerated in Fig. 1.

corrugations would be at angles to each other (that is, the direction of the corrugations, superposed on one trough or crest, would be at an angle to that of the corrugations superposed on an adjacent trough or crest). Thus it may be provided that the superposed corrugations on one trough are at angles to the superposed corrugations on the next adjacent trough, but I may provide that all of the corrugations superposed on the troughs are parallelly inclined (that is, those corrugations superposed on the troughs are inclined in the same direction) and that such inclination of those corrugations which are superposed on the troughs is at an angle to the inclination of the corrugations superposed on the crests. This arrangement also gives very satisfactory operating conditions and insures that the flow shall be so turbulent as to insure that each particle of the sub stance being irradiated is at times exposed directly to the radiant energy without the interposition of any other particle of said substance.

The advantage of employing corrugations or baflies changing their direction is obvious. The particles of material being irradiated, whether small solid particles or particles of a liquid, in flowing along one set of corrugations assume a rolling motion. When the particles leave the set of corrugations extending in one direction and pass onto corrugations extending in another direction this rolling motion is interrupted and a rolling motion in another direction is imparted thereto. This produces a tumbling effect which thoroughly agitates the material being irradiated and tends to bring other portions of the material to the upper surface. For this reason it is possible to irradiate thicker films or layers than is the case when the material flows in a smooth film or layer or when the material flows over a surface having corrugations extending only in one direction. A suitable collecting trough 2! is provided at the bottom of the screen for collecting the milk or other fluid being irradiated and delivering it to a suitable discharge conduit 22.

While I have disclosed two specific embodiments of my invention it is obvious that the invention is susceptible to other types of apparatus and it is not intended to limit the invention to the specific embodiments disclosed herein.

For clearness, the size of the corrugations has The fluid should form a sheet which, While turbulent, is nearly continuous. At any event the fluid should not flow in separate streams over the entire screen but it should to some extent overflow the higher portions forming the walls of the corrugations.

I claim:

1. A liquid irradiating device comprising a screen so placed as to receive radiant energy from an external source, said screen being provided with a plurality of corrugations thereon, said corrugations being inclined to the horizontal and changing said inclination to the horizontal alternately to the right and to the left at spaced intervals throughout the height of the screen.

2. In a device for irradiating substances capable of flowing under the action of gravity, a screen and means for supplying the substance to be irradiated to the top of said screen, said screen being placed to receive the energy radiated from a source of radiant energy and being provided with a plurality of corrugations, said corrugations being composed of sections in zig-zag arrangement and extending generally downward.

3. In a device for irradiating liquids, a screen,

means for supplying liquid to be irradiated to the 75 upper part of the surface of said screen, and means for receiving the irradiated liquid adjacent the lower part of said surface; said surface of the screen being provided with a plurality of corrugations thereon, said corrugations extending generally downwardly from said first-named means toward said second-named means and frequently so changing their direction to the right and left in alternate courses that the arrangement of the corrugations resembles in gross appearance a herring-bone pattern.

4. A device as set forth in claim 3 in which the changes in direction of corrugations are abrupt.

5. A device for irradiating liquids comprising a screen and means for supplying liquid to one surface thereof and collecting irradiated liquid therefrom; said surface of the screen being provided with a plurality of corrugations for conducting the liquid downwardly over said surface, the configuration of said corrugations being such that the liquid is caused to flow sidewardly back and forth across portions of the screen as well as downwardly.

6. An apparatus for exposing flowable material in the form of a turbulently flowing, substantially continuous sheet to radiant energy from an ex- ;ternal source, which apparatus comprises a screen adapted for the turbulent flow of material thereover and for supporting said material during flow, means for supplying material to be irradiated to said screen, and means for receiving material after it has traversed said screen; said screen being provided with a plurality of corrugations extending in a zig-zag direction from one of said means toward the other of said means; such corrugations thus being so positioned relative to the normal direction of flow of particles traversing said screen from said first-named means toward said secondnamed means that particles of material flowing along said corrugations traverse a zig-zag path.

'7. An apparatus for exposing flowable material in the form of a turbulently flowing, substantially continuous sheet to radiant energy from an external source, which apparatus comprises a screen adapted for the turbulent flow of material thereover and for supporting said material during flow, means for supplying material to be irradiated to said screen, and means for receiving material after it has traversed said screen; said screen being provided with flow-deflecting means for defleeting particles" of flowing material, said flowdeflecting means comprising a plurality of relatively elevated and depressed surfaces defining a plurality of zig-zag paths for particles of said flowing material, which zig-zag paths extend from one of the two first-named means toward the other of the two first-named means; such flow-deflecting means thus being so positioned relative to the normal direction of flow of particles traversing said screen from said first-named means toward said second-named means that particles whose flow is deflected by said flow-deflecting means traverse a zig-zag path.

8. An apparatus for exposing flowable material in the form of a turbulently flowing, substantially continuous sheet to radiant energy from an external source, which apparatus comprises a screen adapted for the turbulent flow of material thereover and for supporting said material during flow, means for supplying material to be irradiated to said screen, and means for receiving material after it has traversed said screen; said screen being provided with flow-deflecting means positioned intermediately of the two first-named means and generally defining a plurality of zig-zag paths for particles of said material flowing over said screen; such deflecting means thus being so positioned relative to the normal direction of flow of particles traversing said screen from said first-named means toward said second-named means that particles whose flow is deflected by said flowdeflecting means traverse a zig-zag path.

'9. An apparatus as claimed in claim 8 in which said screen is additionally provided with relatively large corrugations, and in which said flow-deflecting means are superposed on said relatively large corrugations.

10. An apparatus as claimed in claim '7 in which said screen is additionally provided with relatively large horizontal corrugations, and in which said flow-deflectng means are superposed on said relatively large horizontal corrugations.

11. An apparatus as claimed in claim 6 in which said screen is additionally provided with relatively h