US2257542A - Apparatus for treating materials - Google Patents

Description

Sept. 30, 1941. 5, I H 2,257,542

APPARATUS.FOR TREATING MATERIALS v Filed Nov. 4, 1958 s Sheets-Sheet 1 INVENTOR .Flun/izlin S. Smith BY @M, m K vs/k ww-j Sept. 30, 1941. F. 5. SMITH 2,257,542

APPARATUS FOR TREATING MATERIALS Filed Nov. 4, 193a "s Sheets-Sheet 2 9 INVENTOR l Franklin S. Smith,

Y U5 QM M M/WTTORNEYST Sept. 39,1941. F1. 5. SMITH 257,54

APPARATUS FOI I TREATING MATERIALS Filed Nov. 4, 1938 v 5 Sheets-Sheet s INVENTOR F ranklin S. Smith ATTORNEY Sept.30, 1941. F. 8. SMITH 2,257,542

APPARATUS FOR TREATING MATERIALS Filed Nov. 4, 1958 s Sheeis-Sheet 4 1 'IIII. VIII! INVENTOR gran/slim S. Smih Sept. 30, 1941. F. 5. SMITH APPARATUS FOR TREATING MATERIALS Filed NOV. 4, 1938 5 Sheets-Shet 5 Q ti rl INVENTOR Franklin S; Smith BY lllj aw amilo r/ '7maj ATTb NEYs Patented Sept. 30, 1941 UNITED STATES PATENT. OFFICE APPARATUS FOR. TREATING MATERIALS Franklin S. Smith, New Haven, Conn. Application November 4, 1938, Serial No. 238,867

6 Claims.

This invention relates to an art and apparatus for treating food and other products and is especially concerned with sterilizing products by means of an electrical discharge.

One of the objects of this invention is to provide a thoroughly reliable art and apparatus for subjecting food and other products to a treatment in a dependable and practical manner without injury to the product. Another object is to provide an art and apparatus of the above character in which food or other products may be subjected to an electrical treatment. A still further object is to provide an art and apparatus of the above character wherein food or other products may be sterilized without injuring the product in any manner.

Another object is to provide a highly eihcient and thoroughly practical .art and apparatus of the above character which may be used to destroy insects or other life, including all eggs, larvae, and pupae. Another object is to provide an art and apparatus in which these various advantages are obtained and the various functions may 'be readily and efllciently controlled, over wide ranges of usage.

Another object is to provide inexpensive apparatus of the above character, small in size and weight, and capable of dependable and safe operation. A further object is to provide apparatus of the above character which is adapted for use with other apparatus where there are limitations as to the available space which the apparatus must occupy. Other objects. will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combination of elements, arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others, all as will be illustratively described herein, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which are shown some of the various possible embodiments of the electrical and mechanical-features of my invention;

Figure l is a front elevation of the apparatus, some parts being shown diagrammatically, some parts being broken away, and other parts being shown in section;

- Figure 2 is a plan view showing the electrode 7 structure and the path of the material with certain parts broken away;

Figure 3 is a vertical sectional view on the away and others omitted, showing a package in the treatment zone;

Figure 4 is a sectional view of the upper electrode element with the supporting construction and the motor omitted;

Figure 5 is an elevation of a single vertical condenser member;

Figure 6 is an enlarged sectional view of an electrode roller and condenser unit with certain parts broken away;

Figure 7 is a vertical section on the line 1-1 of Figure 6; I

Figure 8 is a view with certain parts broken away showing the upper electrode structure and the parts associated therewith; and

Figure 9 is a view similar to Figure 8 but showing a modified form of the electrode construction. 1

This application is a continuation-in-part of my copending application Serial No. 157,699, filed August 6, 1937, entitled Method and apparatus for treating materials."

The particular embodiment disclosed herein operates to pass products such as packages of food through a discharge zone where they are subjected to a high potential with the result that discharges take place within the products. When this apparatus is used in a manner explained in detail below, these discharges are of a corona-like disruptive nature and thoroughly treat the entire product. It has been found that high practical and desirable results areithus obtained with apparatus which is light in weight, compact, and economical to build and use.

Referring to Figure 1, the apparatus includes upper and lower electrode structures, generally referred to by the numerals 2 and'l, respectively having a discharge zone 3, therebetween. The product being treated is moved through this treatment zone and, at the same time, a highfrequency, high-potential voltage is impressed across the two electrode structures so as to cause a disruptive corona-like discharge through the product.

line H of figure 1, certain parts being broken The product being treated enters the machine at the right (see also Figure 2) through opening 5, and leaves the machine at the left through opening 6, thus moving through the machine upon a roller conveyor system which includes a group of dielectric rollers 9 at the right, a group of electrode rollers III at the center, and a group of dielectric rollers II at the left. As has been explained in my copending application, Serial No. 157,699, movement of the product is obtained by rotating the rollers and the path of the product may be determined by means such as guide rails of dielectric material positioned above rotatably mounted and are rotated by an endless belt i2 which contacts the underside of each roller 9 and ii at one end and each electrode roller it (see also Figure 3) to the right of the center thereon Endless belt i2 is carried by pulleys id and it and is driven through a speed reduction gear unit connected to pulley ill by a motor it (Figure 2).

The upper electrode structure 2 includes a plurality of electrode units which are mounted upon a cylindrical shell construction, generally indicated by the numeral ii, the details of which will be pointed out below. In this embodiment, a group of twenty-one electrode units are evenly spaced along the shell construction i'l, one electrode unit, generally indicated at it, being positioned at each end of the group, and there bein nineteen (see also Figure 8) electrode units, gen

erally indicated at 88. Shell construction ii is rotatable and is provided with two electric motors and a central fixed shaft, the entire structure being supported at theends by a pair of end brackets 20.

As best shown in Figure 4:, each electrode unit 15 is formed by four electrode elements 2! of generally tear-shaped configuration which extend arcuately and are connected together to form a ring surrounding shell construction H;

electrode units i8 are similarly formed. by electrode elements 22 having substantially similar configuration to elements 2!. The details of construction and assembly will be more fully pointed out below.

' with an integral supporting pin 28. During operation, the gas in each electrode roller i0 ionizes thus forming a conductive path extending along the axis of the electrode roller throughout its length and into cap 26. The left end of each electrode roller cooperates with the upper electrode elements 2| and 22 above it, and there is thus formed a discharge zone in which discharges occur emanating from the electrode elements 2| and 22 above and extending to the electrode rollers l0 below.

As shown best in Figure 1, the entire apparatus is mounted in a casing 30 having legs 32 and sheet metal side walls. The high-frequency, highpotential voltage is produced by apparatus of the type shown in my prior Patent 1,975,805, issued roof of casing 30; there being at the right a highfrequency, low-voltage alternator 33; at the left a power-factor compensating resonance coil 34 and additional potential regulating means; and in the center a high-voltage auto-transformer 36, A suitable meter and control apparatus is October 9, .1934, and is mounted mainly upon the r mounted in casing 30 adjacent alternator 33 and includes switches 38 and voltmeter l0.

As explained in my prior Patent 1,925,805 and in my'copending application Serial No. auto-transformer 36 receives the high-frequency, low-voltage of alternator 33 and transforms this into a high-frequency, high-voltage which is im.- pressed across the upper and lower electrode aceta es structures 2 and 5 respectively to produce the disruptive corona-like discharges.- One end of the winding of auto-transformer 36 is grounded,

and the other end is connected to a lead extend-v ing downwardly through terminal t2, and thus,

across the portion of the'auto-transformer winding between the tap and the grounded end.

Mounted below auto-transformer it within the same casing is an insulation transformer (not shown) by means of which a suitable voltage is supplied to the motors which rotate the upper electrodes. This insulation transformer has a primary winding connected to a suitable source of alternating current (not shown) through a pair of terminals at (only one of which is shown). The secondary winding of theinsulation transformer is electrically connected through terminal 32 to the electrode motors and this winding is insulated from its primary winding for a voltage corresponding to the maximum output potential of the auto-transformer.

The lower electrode structure is electrically to the right of the center thereof, and being in the form of a bridge member 48 (see also Figure l) of dielectric material such as Bakelite;

Positioned upon the top of bridge member 48 is a plate 50 (Figure 3) also of dielectric material vwhich extends to the left and carries a plurality of spacers 52. Spacers 52 are positioned-between the electrode rollers and, as shown best in Figure 1, are wedge-shaped with concave sides which fit the contour of the adjacent portions of the electrode rollers. The electrode rollers lie upon the upper web of endless belt l2 (Figure 3) which in turn lies upon and slides along plate 50; the right hand end of each roller is held in position by its supporting shaft 28 and the electrode rollers are held in alignment by spacers 52. Thus, when endless belt l2 moves, the electrode rollers rotate together, and material supported by them is passed from one roller to the other through the treatment zone. 7

The center ofgravity of each of the electrode rollers is to the left of bridge member 8, and accordingly, as shown best in Figures 5 and 6, the supporting shaft 28 of each of the electrode rollers fits into an inverted-U-groove 54 in its vertical condenser member 48. Attached to the end of each supporting shaft 28 is an antifriction bearing unit generally indicated by the numeral 56, the details of construction of which are shown in Figure '7. This anti-friction bearing unit includes. a spherical stationary member 58 having a removable screw plug Eli and carrying the outer race 59a of a ball bearing unit. The inner race 59!; of the ball bearing unit is rigidly.

clamped to supporting shaft 28 by means of a stud bolt 62.

In this manner the electrode roller Ill may be easily removed by moving the right end (Figure 6) downwardly and to the left. However, the electrode rollers are held securely in position, and .as indicated above, may be easily rotated by endless belt l2 to support the material and move it through the treatment zone. The vertical condenser elements 46 (see Figures 3 and 6) are supported by two horizontal bars 64 which are in turn supported at their ends by a pair of brackets 66 extending from the bottom of the casing 3!]. Horizontal bars 64 and brackets 66 are of dielectric material such as Bakelite.

Referring again to Figure l, the 'upper'electrode structure 2 is adjustably supported from the roof of casing 30 in the manner described in detail in my copending application, Serial No. 157,699, there being a main insulator which is formed by cutting segments from a cylinder of insulating material and which has four downwardly extending arms 61. Integral with the lower ends of arms 61 is a ring portion 68 to which is rigidly attached the elongated frame ID of the electrode structure 2. This connection between ring portion 68 and elongated frame 18 is by means of two arcuate brackets 12 (see also Figure 2) which carry two horizontal bars 14 having the'brackets 20' upon their ends. Thus,

a rigid support is provided for the upper electrode structure and the position of the electrode structure may be changed by means of the adjustable support for the main insulator.

As pointed out above, the electrode units i5 and [8 are rigidly mounted upon the cylindrical shell construction I! and, as shown best in Figure 4, are secured in place by set screws 16. Each electrode unit l5 comprises four electrode elements ill, and each electrode unit I8 comprises four electrode elements 22. The electrode elements of each unit are evenly spaced around the shell construction l1, and, as the electrode unit rotates, these various elements successively move to the lower position so that discharges occur therefrom. .The electrode units are also evenly spaced axially along the shell construction, and are spaced arcuately and so positioned that the effective discharge areas of the electrode elements are positioned on nested substantially helical lines along the axis of rotation (see also Figure 3). Eight helical lines are formed by spacing the electrode elements of alternate electrode units in alignment along one set of lines, and then spacing the electrode elements of the intermediate units along another set of lines 'which are spaced respectively 45 from the first set of lines. Each of the lines extends the full length of the shell construction I! and extends substantially 45 arcuately.

As pointed out above, there are illustratively nineteen electrode units l8 and two electrode units 15 making a total of twenty-one electrode units. Accordingly, the electrode elements of units i5 and those of nine of the electrode units l8 are positioned along one set of helical lines. This relationship is best shown in Figure 3, where one unit l5a appears in the right foreground and the other unit [5b appears in the left background;

the electrode elements ofthe nine even num-' bered electrode units l8, that is the second, fourth, sixth, etc., units, are in alignment with the respective'electrode elements of units lid and lib.

Spaced arcuately 45 from the electrode elements of unit |5a are the electrode elements of the first unit l8, and in a like manner, spaced arcuately 45 from the electrode elements of unit I5b are the electrode elements of the nineteenth unit [8; the electrode elements of the odd numbered units l8, that is, the third, fifth, seventh, etc., units, are positioned along lines extending between the respective electrode elements of the first and nineteenth units l8. With this spacing of the electrode elements, the rotating electrode construction is properly balanced from a mechanical standpoint, and accurate control is maintained on the discharges so that treatment is uniform throughout the treatment zone.

The details of the mounting means for the upper electrode structure are best shown in'Figure 8 wherein a rigid shaft extends between the end brackets 20 and carries the stationary elements of the two electrode motors as well as the ,shell construction IT. The shaft is formed by a cylindrical center portion and two end portions which are received in hubsextending inwardly from end brackets 28. The shell construction I! is supported adjacent its two ends on'the shaft by a pair of roller bearings units 18, each of which is mounted as shown at the right with its inner race clamped to the shaft, and the outer drical supporting frame member 82 and an end ring 84.

The electrode motors are of the squirrel-cage type with a wound stator 86 mounted upon the shaft and arotor 88 mounted upon the shell. Each of the rotors is held by a retaining ring 92 against an inwardly extending flange 90 integral with the shell 80. Retaining rings 92 are secured in place by set screws (not shown) extending inwardly from the shell. At each end of the shell, the and ring 83 and the frame member 82 are held in position by a plurality of screws 94 extending into tapped holes in the retaining ring 92.

As shown best at the right of Figure 8,each of the stators 86 is clamped against a ring 96 by a flanged nut 98, the flange of which extends over the edge of the stator winding to provide a shield. The left hand end of the winding is protected by a similar shield Hill. A collar I02 is fitted against nut 98, and the inner ring of the ball bearing unit is clamped against this collar by a nut I04 which is provided with a suitners from which disruptive sparks might ema-.

nate. Accordingly, each of the end brackets 20 is provided with a shield I08, and the ends of horizontal bars 14 are covered by shields H8. In addition to this and'in order to obtain more accurate control of the discharges at the ends of the treatment zone, the endelectrode units l5 comprise electrode elements 2| which are wider than the electrode elements 22, and the curvature is less at their effective discharge surfaces; thus, excessive flux concentration is avoided.

Each of the stators 86 is provided with a main winding and a starting winding, and eachof the starting windings has connected in series therewith a condenser which is positioned in the adjacent end bracket 20 and protected by the shield I08. As indicated above, power is supplied to the electrode motors through an insulation transformer positioned below the highpotential transformerand in'the' same casing. One side of the secondary winding of this insulation transformer is connected to the high-potential lead running from the high-potential transformer to the electrode structure. This lead is electrically connected to the supporting frame, and one side of the main and starting windings of each electrode motor is also electrically connected to the supporting frame. The remaining side of the secondary winding of the insulation transformer is in turn electrically connected to the remaining sides of each of the motor windings through suitable leads, the connections to the starting windings being through the respective condensers.

In order to insure the maintenance of a good electrical connection from the rotating electrode structure to the supporting frame, and thus with the high-potential side of the high-potential transformer, two spring pressed brushes II2 are provided, one of which extends inwardly from each of the end brackets 20. Each brush II2 rides upon a washer-shaped collector ring IIQ which is rigidly held to its end ring 8| by a plurality of screws H6. Collector rings III snugly fit the supporting shaft and thus eifective-' ly prevent the entry of foreign materials to the interior of the shell construction.

The details of construction of the vertical con-1 denser elements 40 are best shown in Figures 5, 6,

and 7. The main portion of the element is a flat, metal tube, and this is reinforced. at the points of support and at the inverted-U-slot 5!. Concentration of flux at the ends of the tube is prevented by a pair of shields II5. Each condenser element is supported by a pair of studs II8, one of which extends to each of the horizontal supporting bars 64. With Lthe condenser electrode unit shown in Figure 6, these studs are positioned at the tops of the horizontal bars 04, and alternate condenser elements are supported in this manner, but, as shown in Figure 1, the

intermediate condenser elements are supported by struts positioned at the bottom of these horizontal bars. Thus, referring to Figure 3,. there is a stud IIO positioned at the top of each of the bars 6! and connected to the nearest or first condenser element, and there is another stud I I0 at the bottom of each of the horizontal bars which is connected to the second condenser element.

As indicated above, the electrode rollers 24 are formed of tubes of dielectric material such as low power-factor glass or fused quartz, and these tubes are filled with neon gas'. During operation, this gas is ionized, and thus forms an electrical path along the axis of the electrode roller.

condenser element is completed through cap 26 of which is formed by the ionized gas within the soldered in place.

The discharges occur between the upper electrode structure 2 and the upper surface of the electrode rollers. each electrode roller cooperates with its condenser element to form an operating electrode-condenser unit. In order to maintain uniform if conditions throughout the treatment zone, it is important that the various electrodehave substantially uniform eleccondenser units trical characteristics.

There are-variations in the thickness of the walls of the various dielectric tubes, and at times it has been difficult to'compensate electrically for these variations. However, the electrical connection between the electrode roller and its electrode roller; this condenser is thus electrical ly in series with the ionized gas. The capacitance of this condenser may be varied by changing the surface area of the metallic coating I20; in this manner, each condenser is given a value dependout upon the wall thickness of the particular dielectric tube. Thus, the variations in the wall thickness of the various tubes are individually compensated for, and the electrical characteristics of the various operating units are made uniform.

In the manufacture of these electrode rollers, the entire dielecetric tube is ground to a uniform diameter, and then the metallic coating I20 is applied by means of a metal spray gun, the metallic coating in this embodiment being solder. Subsequently, the surface of the metallic coating I20 is accurately ground to fit the inner surface of cap 26; cap 26 is then properly positioned and During these operations, the series capacitance of the electrode roller is measured and-is adjusted to a predetermined value by varying the surface area of the metallic coating I20 and the length of cap 26. j

In the modified embodiment of the upper electrode structure shown in Figure 9, the electrode elements 2I8. are toroidal, and they are'mounted upon the shell construction II in a manner similar to that of electrode elements I5 and I8. The electrode elements 2I8 snugly .fit the shell I1 and are-held securely in place 'by spacer collars 222; spacer collars 222 are held rigid to shell H by set screws 224. At' each end of shell. II, a flanged end ring 226 holds the adjacent electrode element in place. Illustratively, there are fourteen electrode elements 2I8, the seven electrode which is toroidal in shape with its axis at an angle to the axis of rotation. The discharges between the lower electrode structure and each of the electrode elements 2I8 are at all times concentrated at the portion of the discharge surface 220 which is at the bottom, and this-shall be referred to as the active discharge surface."

With one of the electrode elements in the position shown at the left of Figure 9, the active discharge surface is at the right limit; and after the rotating electrode structure moves through this electrode element will be in the posltion of theelectrode element shown at the right of Figure 9; during this movement, the

.active discharge surface moves to the left limit.

their operation may be similar to that of the I preferred embodiment.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth or shown in the accompanyingdrawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In electricaltreating apparatus, an electrode roller comprising, a gas filled tube of dielectric material, and an electrical contact and mechanical supporting construction for said tube comprising a metallic coating upon one end of said tube and a cylindrical shell in intimate contact with said coating and having a pivot extending therefrom, the gas within said tube when ionized forming an extended electrode surface and being electrically connected through said metallic coating and said shell to said pivot.

2. In apparatus of the class described, an

electrode roller-condenser construction comprising, an electrode roller adapted to extend horizontally into the treatment zone and support the material being treated, means positioned within said roller to provide an electrical conducting path along the axis of said roller, and a vertically extending condenser element positioned adjacent said electrode roller and mechanically and electrically connected thereto. said condenser element comprising a flat tubular member with enlarged end portions.

3. In apparatus of the class described, an electrode roller-condenser construction comprising, an electrode roller adapted to extend horizontally into the treatment zone and support the material being treated, means positioned within said roller to provide an electrical conducting path along the axis of said roller, and a vertically extending condenser element positioned adjacent said electrode roller and mechanically and electrically connected thereto, the electrical connection between said electrode roller and said condenser being by means of a metallic cup at the end of said electrode roller.

4. In electrical apparatus of the character described, the combination of a sealed tube of dielectric material containing material capable of acting as an electrical conducting medium and capable of forming one plate of a connecting condenser element; and means providing support for ,the tube and also forming the other plate of the connecting condenser element comprising, a surface-covering material upon the exterior surface of said tube, and a rigid support means extending about said surface-covering material.

5. In electrical treating apparatus, a condenser construction formed by a pair of condenser-plate structures positioned in cooperating relationship, one of said condenser-plate structures comprising a plurality of elongated elements which are substantially fiat with enlarged end portions, each of said elongated elements having one of its extended surfaces as its active condenser surface and said elongated elements being positioned with all of the active condenser surfaces substantially in a single plane.

6. In electrical apparatus of the class described, the combination of: a sealed tube of dielectric material containing material capable of acting as an electrical conducting medium and capable of forming one plate of a connecting condenser element; a metallic shell structure intimately contacting the surface of the tube and forming the other plate of the connecting condenser element; and a rigid support means mechanically connected to said shell structure.

FRANKIJN S. SMITH.

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