US3477873A - Sugar beet processing - Google Patents

Description

Nov. l1", 1969 Filed Oct. 5, 1966 L. M. KOELSCH SUGAR BEET PROCESSING 5 Sheets-Sheet 1 Nov. ll, 1969 L, M. KoELscH SUGAR BEET PROCESSING 5 Sheets-Sheet E Filed Oct. 5. 1966 Nov. 11, 1969 l.. M. KoELscH l 3,477,873

' SUGAR BEET PROCESS ING Filed oct. s, 196e s sheets-Sheet DFF/56650 Z: gnam/RAG im ya 1 V557/044. P19555 Y l 5557 PUMP I NVE-YTOR.

ATTOR YS United States Patent O,

3,477,873 SUGAR BEET PROCESSING Lester M. Koelsch, Pittsfield, Mass., assigner to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Oct. 3, 1966, Ser. No. 583,638 Int. Cl. C13d 1/08 U.S. Cl. 127-43 5 Claims ABSTRACT F THE DISCLOSURE A process of treating whole sugar beets comprising chipping the beets into thin beet chips, deiibering the chips into distinct beet fibrils, pressing the beet fibrils without the addition of foreign liquids to remove sugar-containing juices therefrom and removing granulated sugar from the sugar-containing beet juices.

This invention relates generally to sugar beets, and more specifically, to a novel process of extracting a maximum amount of sugar-containing beet juice from sugar beets.

A more particular object of the invention is the provision of app-aratus for use in the process wherein whole beets are uniformly chipped and then defibered and the detibered beets are pressed sufficiently to rupture the cell walls of the individual beet fibers. Such rupturing of the beet cell walls allows the full release of the sugarcontaining liquid from its natural sites, which is then easily separated from their residual solids.

A further object of the invention is the provision of apparatus, adopted for continuous operation in a process, wherein the rupturing of beet cell walls is eifectuated by uniform fibrilating of beets and thereafter pressing them in a vertical screw press.

A further particular object of the invention involves a method for treating sugar beets involving in one form a rotary cutter head, means for guiding to the head, along a p-ath which approaches the head approximately radially, beets extending perpendicularly to the axis of the head, means for positively feeding the beets along said path, and, mounted on the peripheral head at spaced locations around the head, Slicers whose cutting edges extend lengthwise of the head and whose outer ends are concentric with said axis so that there is no clearance behind said edges, and means for debering the beet chips including a pair of relatively rotating plates having defibering means on the surface thereof, and means for pressing the defibered beets including an annular enclosure with radial perforations therein and an auger within the perforations having advancing flights on the auger with an auger for supporting the fiights and said core increasing in diameter with the depths of the flights increasing from a receiving end to a discharge end.

The production of sugar from sugar beets is a well established industry in this country and abroad. One of the major problems in this industry concerns the initial preparation of the sugar-containing liquid from the beets. The beets, on the average, contain from 13 to 17% sugar (sucrose) and 0.8% ash, and are approximately 6 to l5 inches in diameter, averaging about 8 to 10 inches in diameter. The diameter of the beet being measured perpendicularly to the plane tangent to the fields of growth. At harvest time the beets are uprooted from the fields with specialized machines. Field workers follow the machines, remove the dirt and leaves from the beets, and load them for shipment to the factory. The beets enter the factory by way of flumes, small canals filled with Warm water, which not only transport the beets but wash them as well. The prevalent practice for obtaining sugar-containing liquid is known as diffusion, and involves slicing 3,477,873 Patented Nov. 11, 1969 ICCl the beets into long narrow strips called cossettes, then treating the cossettes in a batch or continuous diffuser with hot water. One widely used type of continuous diffuser consists of a series of large tanks or cells, 12 or 14 of which are connected in a series to form a diffusion battery. The sugar is extracted counter-currently with heated water. Each diffusion cell is set several inches higher than itspredecessor so that the sugar-containing liquid may flow by gravity through the diffusion battery. The cossettes are fed into the diffuser at one end of the lower tier and are carried by drag chain equipment with perforated steel plate flights from one cell to another through the entire length of the diffuser and finally discharged at the opposite end. The important point about diffusion is that it, as the name implies, is dependent upon diffusion of the sugar-containing liquid from the beet cells within the cossettes into the aqueous phase surrounding the cossettes. Since this diffusion process through the cellular material is by necessity relatively slow, this method of obtaining the beet juice involves a long processing time and bulky equipment which must occupy a large part of iioor space of a factory. The beet cossettes, after they are removed from the diffuser, are sent to a drier where the moisture content is reduced and they are pelletalized or otherwise processed and sold as cattle feed. The removed sugarcontaining liquid is then passed on to a purifier. The resulting sugar-containing liquid is purified by repeatedly precipitating calcium carbonate, calcium sulfide, or both in it. Colloidal impurities are entangled in the growing crystal of precipitate and removed by continuous filtration. The resulting solution is nearly colorless and the sugar (sucrose) is concentrated by multiple-effect vacuum evaporation. The syrup is heated, cooled, centrifuged and the crystals are washed with water and dried. The dried crystals are then granulated, screened and packed.

Although the disadvantages of thus processing the beets, by preparing them in the requisite cossette form and diffusion, are well known and much experimentation has been done to devise methods to recover the sugar-containing liquid in a more anvantageous way, no widely used successful alternative has heretofore been advanced. Further, there are other obvious resulting disadvantages in the present process in that excessive Water must, by necessity, be used at the diffusion station and during the subsequent purification steps in order to extract a .maximum amount of beet juice, which must be removed prior to the extraction of the dried sugar crystals. The spent cossettes must also be sufficiently dried in order to be useful as a by-product. Naturally, this dehydration substantially adds to the cost of producing sugar. Further, excessive time and equipment is required for the diffusion process and the subsequent liltrations and washings.

It has now been found that the necessity for slicing beets into cossettes and then diffusing them can be eliminated by a novel treatment of the sugar beets. It has further been found that the time and equipment necessary to extract sugar from the sugar beets can be considerably reduced, thereby allowing for more economical production of sugar. It has yet further been found that sugar can be extracted from sugar beets with the use of substantially less water than has heretofore been possible, thereby allowing for further economical production of sugar. This process involves, among other things, chipping the whole beet into uniform beet chips and fibrillating the beet chips into uniform beet fibers; thereafter subjecting the beet fibers to a screw press whereby a maximum amount of sugar-containing liquid is removed without the necessity of adding any additional liquids and then leaching the initially dehydrated beet fibers in warm water and again pressing these fibers so as to remove any additional sugar q remaining therein. Dehydrated beet pulp can then be dried by internal rotary air driers or some such drier, as for example, but not limited thereto, such as disclosed by Robert A. Daane in copending application Ser. No. 413,263, filed Nov. 23, 1964 (now Patent No. 3,363,665), so as to reduce the moisture content of the beet pulp to approximately 5 to 15% moisture and thereafter be properly pelletized to be sold as cattle feed, plastic filler, insulating board, furfural and other such like uses for spent beet sugar pulp. The initially expressed sugar-containing liquid is of course highly concentrated in sugar content, and even when `mixed with the sugar-containing liquid obtained from subsequent screw presses does not require as much evaporation, as would be required if the presently known diiusion was employed because of its lower non-sugar-containing liquid.

It was the initial thought of those skilled in the art of sugar beet processing that diffusion was necessary, as any other process for the removal of sugar from sugar beets would tend to destroy it or in some way impair the quality of the sugar therein. However, it has been found that this is not true. It has now been found that complete rupturing of the cell walls is desirable so as to remove the maximum beet juice therefrom and thus obtain the maximum amount of sugar from the beets.

Chipping and brillating beets is much more economical, less time consuming, and only requires a minimum amount of equipment. The beet juice may be readily removed from the individual bers by applying substantial amounts of pressure to rupture the individual cells that make up the beet ber and thereby express the sugarcontaining liquid, Since the cell walls are ruptured, the sugar-containing liquid can ow freely out of the tissue, and the movement of the sugar-containing liquid is no longer limited by the physical process of diffusion through cell walls and other intact tissue.

By processing in accordance with this invention, the rupturing of the cell walls is essentially complete and uniform. That is, essentially every cell in the beet piece is opened and the juice content of every cell thus released. The reason for such uniform action lies in the physical size of the beet fibers and the action of the screw press acting upon the ibrillated beets. This situation can be explained as follows: Consider a single ber beet -being uniformly pressed. When the pressure is increased on the individual cell, the liquid content thereof willl be forced to surge with great force to the walls of the cell, stretching the walls and nally rupturing them, leaving a collapsed cell containing no liquid therein.

An important feature of this invention is that the treatment does not adversely effect the beet juice recovered from the lbeets. Experimental investigations have shown that the quality of the raw juice obtained from the beet pulp is not substantially lower than the quality of the juice obtained by diffusion process. In particular, it is observed that the proportion of inverted sugar, pectin and nitrogeneous components are not significantly greater in the raw beet juice from beet pulp than the diffusion juice. In' fact, in some cases it has been observed that the sugarcontaining liquid obtained by the process of this invention is of better quality, particularly after the usual purification, than comparable purified juice from the diffusion process. The fact that the juice obtained in accordance with this process equals or exceeds the quality of the juice obtained by the diffusion process is surprising indeed when it is considered that the pressing of fbrillated beets, in accordance with this invention, causes disintegration of the beet ber and it would be expected that this disintegration would cause the beet juice to contain excessive amounts of high molecular weight compounds such as pectins and proteins which in the usual diffusion process would tend to remain in the tissue because they could not diffuse through the intact cell walls.

Another feature of this invention is that it is particularly adopted for continuous operation. Once the beet chips have been properly brillated, the pressing, leaching and purifying steps may be placed under positive pressure and completely sealed off from atmospheric environment. Further, when the process is completely under pressure it is possible to completely regulate the amount of time the #beet fibers spend at a particular stage of the desugaring process, thereby obtaining the maximum amount of sugar from the beet. The advantages of continuous operation include reduction of retention time that the beets are processed, saving in labor and steam, dilution of the pulp with condensed steam and/ or Water is lessened and equipment of relatively small size can be used to process large amounts of beets.

Further objects and advantages of the invention will become more apparent from the description herein and the annexed drawings in which:

FIGURE l is a diagrammatic showing of a preferred form of the process of the present invention;

FIGURE 2 is a diagrammatic showing of a preferred form of the debering device used in the present invention;

FIGURE 3 is a partial sectional view taken substantially along the lines III-III of FIGURE 2 and showing the upper and lower debering surfaces in their approximate operative relationship;

FIGURE 4 is a diagrammatic showing of a perforated form of one of the attrition surfaces;

FIGURE 5 is a further diagrammatic showing of the working relationship of the attrition surfaces of FIGURES 3 and 4;

FIGURE `6 is an elevational view illustrating the preferred form of the screw press used in the present invention;

FIGURE 7 is a partial elevational view illustrating the preferred form of the beet chipper used in the present invention; and

FIGURE 8 is a diagrammatic showing of the pump VIII shown in FIGURE l feeding the defibered beets into the vertical press.

As shown in FIGURE 1, the numeral 10i represents a bin for receiving the beets from the harvesting field. The bin 10, has a suitable discharge mechanism (not shown) which permits the beets to pass downwardly, either directly, or to a conveyor or other such suitable carrying means (not shown). The beets are thus continuously fed into a chipping mechanism 2 wherein they are uniformly chipped. The chipped beets are then fed into a debering mechanism 3 wherein the beet chips are uniformly defbered to form beet iiberlets. The fibrilated beets may then be continuously fed, under pressure if desired, as illustrated by the dotted circle VIII, but without the addition of any liquid, to a first vertical screw press 4 where the fibrilated beets are initially pressed to remove a substantial amount of the beet juice. The `rst screw press removes approximately 50 to 90% and preferably 50 to 85% of the sugar-containing liquid. The spent beet pulp, which is discharged at the bottom of the screw press, as will be explained in greater detail hereinafter, is then fed into a leaching tank 5 wherein warm water, in its pure form, or with the addition of suitable additive chemicals to aid in the leaching process, is added, and any remaining sugar in the initially pressed beet fiberlets is again brought into solution. The leaching tank 5 is so regulated as to add to 95% liquid to the spent beet pulp. The rewetted beet iiberlets are continuously fed, again under pressure as illustrated by the dotted circle VIII, into a second screw press 6. The second screw press 6 again presses the beet berlets so as to remove a substantial amount of the liquid contained therein and passes the spent beet pulp to a drier 7, which may be an internal rotary air drier, or one such as disclosed in copending application 413,263 (now Patent No. 3,363,665) mentioned previously, and incorporated herein by reference, capable of reducing the moisture content in the beet pulp to approximately 5 to 15% liquid. The second, and subsequent screw presses, if any, remove approximately 50 to 90% and preferably 8() to 85% sugar-containing liquid. The sugar containing liquid from the first press 4 and from the second press 6 are continuously fed into a purier 8, which is of conventional construction, and contains therein carbonators, filters, limers, sulfonators, and concentrators. The puried and concentrated sugar-containing liquid is directly fed into vacuum pan crystallizers 9 wherein the resulting syrup is seeded to allow sugar crystals to grow. The crystallized sugar-containing syrup is then directly fed into a centrifuge 11 wherein the syrup is separated from the crystallized sugar. The crystallized sugar is then fed into the `washer 12, wherein the crystallized sugar is washed to remove the coarse sugar products, and the pure sugar crystals are then fed into the sugar drier 13. The pure sugar crystals are dried in a sugar drier 13 and then fed into a granulator 14, which is a horizontal rotating drum having a series of narrow ilights attached to its inner surface. These flights lift the sugar and allow it to fall through a stream of hot air iiowing counter-current to it. Of course, if desired, any other form of granulator may be used. The dried sugar crystals are then fed into a series of screens 15 where they are graded according to size. The various automatic weighing and packing machines 16 pack the sugar in barrels, sacks and boxes.

As shown in detail in FIGURE 2, a preferred embodiment of a mechanical pulping and delibering device is similar to the device disclosed and claimed by Alexander D. Cormack, Martin O. Saltarelli, James B. Scott and Cho-Yee Yeung in copending application Ser. No. 430,- 437 led Feb. 4, 1965 (now Patent No. 3,387,796), incorporated herein by reference, which is capable of performing the detibering of the sugar beet cossettes. It will be understood however that other types of defibering devices may be employed including impacting structures such as hammer mills. It consists of a generally cylindrical housing 20 defining a pulping chamber 21 having a relatively large upwardly facing opening 22 for the introduction of the sugar beet cossettes. Within the pulping chamber 21 and supported from the upper wall 23 thereof is an upper defibering disc or a stator 24 having a deiibering or attrition surface 24a thereon. Also within the pulping chamber 21 is a lower deibering disc or rotor 25 having a suitable attrition surface 25a thereon. Lower defibering disc 25 is mounted on shaft 31 which is connected to a suitable motor 32. The attrition surfaces 24a and 25a define therebetween a prebreaking zone 43, an initial debering zone 44, and a final deibering zone 45 as indicated schematically in FIGURES 3 and 4 hereof. The central portion of the rotor 25 is conically shaped and extends upwardly through the upper stator 24 and denes a distributing zone 26 for uniformly distributing the beet cossettes throughout prebreaking zone 43. The distributing zone may consist of a generally conical shaped member having a plurality of radially extending distributing vanes 62 attached thereto, best seen in FIGURE 3. The vanes 62 extend generally downwardly along the conical portion of the conical member so as to direct the beet cossettes toward the entrance portion of the prebreak zone 43. The distributing zone 26 thus supplies a uniform amount of material to each circumferential section of the entrance portion of the prebreak zone 26. It is important that distribution be as even as possible since with the uneven circumferential distribution the beet cossettes must be retained in the defibering zone for a substantially longer period of time, resulting in undue raise in temperature and damage to the individual bers. The distributing zone 26 is in open communication with the entrance portion 22 of the debering device and the entrance portion 22 is in open communi-cation with the ambient atmosphere.

The material prebreaking zone 43 may consist of a plurality of radially extending bars mounted on inner annular portions of the upper and lower stator and rotor respectively. This material prebreaking zone is relatively wide at the entrance portion 27 thereof and gradually decreases in width in a radially outwardly direction. The beet cossette prebreaking zone 43 is in open communication with the material distributing zone 26 and is thus continuously vented to ambient atmosphere.

As the material leaves the prebreaking zone in a radially outwardly direction it enters into the rst deiibering zone 44 4which consists of a plurality of generally parallel grooves and ridges mounted on opposed intermediate annular portions at the upper and lower stator and rotor respectively. The entrance portion 28 of the initial defibering zone 44 is in open communication with the material prebreaking zone 43 and thus continuously vented to ambient atmosphere. As brous beet cossettes leave the initial deiibering zone 44 in a generally radially outwardly direction they are forced into a final debering zone 45 defined by opposed outer annular portions of said upper and lower stator and rotor respectively. The nal debering zone consists of radially extending angularly spaced grooves and ridges mounted on said upper and lower angular portion of said stator and rotor respectively.

From the final debering zone the fibrous beets are thrown radially outwardly into the pulping chamber 21 from which they are removed through an exit port 29, which is preferably tangential to the housing 20. Although only one exit port is shown, if desired, any number of such tangential exit ports may be provided around the periphery of the housing.

A dilution agent or other suitable carrying media, such as steam, for the brous beets may be supplied to the beet mass through the supply line 30v by which the consistency of the brous beets may be controlled and regulated.

In operation the sugar beet cossettes are supplied to the entrance portion 22 of the debering device 2 of a temperature range of from 50 C. to 35 C. A suitable dilution agent may be added to the beet cossettes to obtain a mass having a consistency of about 1% to 100% and preferably 30% to 40%. The beet cossettes are. then deposited in a continuously vented distributing zone 26 -whereby the material is uniformly distributed throughout the continuously vented prebreaking zone 27. In prebreaking zone 27 the larger beet cossettes are reduced to fiber bundles having an approximate average bundle size of the beet mass and at this point the initial raise in temperature of the librous beets starts, due to the mechanical working action of the breaker bars in the prebreaking zone.

The breaker bars are generally trapezoidal in crosssectional area which gradually decreases in a radially outward direction. Preferably the base dimension of the trapezoid is from .50 inch to 1.0 inch and the angle deiined between the sides of the trapezoid and the vertical line may vary from 16 to 24 and is preferably in the neighborhood of 20. The height of the trapezoid may vary from approximately .50 inch to 1.0 inch and is preferably .70 inch at the innermost extremity thereof and then gradually decreases to a height from between 0 inch to 1.0 inch and is preferably .7 inch. The preferred number of breaker bars on each disc may vary from 4 to 32 but lies preferably in the neighborhood of 16. A small number of breaker bars will result in insucient prebreaking of the larger chunks of beets while too large a number of breaker bars will cause an unnecessary rise in ternperature of the beets at too rapid a rate. The breaker bars of the lower disc 42 are substantially similar to the breaker bars of the upper disc as described above with the exception that the rate at which the cross-sectional area decreases is substantially smaller and the height may vary from a maximum dimension of .50 inch to 1.0 inch and preferably is .70 inch and gradually decreasing to a minimum height of from 0 inch to 1 inch and preferably .40 inch. The breaker bars of the upper disc 41 are stationary while the breaker bars of the lower disc 42 are rotatable with respect to the upper disc and therefore serve the local function of breaking up the larger beet fiber bundles and moving these beet fibers radially outwardly. From the prebreaking zone 27 the fibrous beets are continuously fed to continuously vented initial defibering zone 44 defined by opposed close running attrition surfaces 24a and 25a. In the initial defibering zone 44 the sugar beet fibers are subjected to mechanical rubbing and rolling action under controlled conditions of temperature and pressure. More specifically in the initial defibering zone the attrition surfaces impart a mechanical action to the fibrous beets thus rapidly raising the temperature of the mass. Due to the sudden rise in temperature of the mass a relatively large amount of steam is created which is permitted to rapidly escape through the open spaces between the beet cossettes in the prebreaking zone. The rapid escape of steam from the initial :defibering zone avoids the creation of back pressure in said zone, thereby substantially increasing the uniformity of the beet cossettes fed into the defibering zone resulting in better uniformity of product. The individual undeveloped fibers are obtained through the mechanical action of the opposed close running attrition surfaces in the initial defibering zone. These undeveloped fibers are not of suitable diameter to insure uniform application of pressure to each cell making up such fiber, because of their relatively large size. The desired pressing characteristics of the individual ber depends in large on the extent to which such relatively large fibers are fibrilated. That is, to the extent to which the undeveloped fibers are further worked on to produce a multiplicity of fibers or fibrils therefrom.

As shown in FIGURE 3, which is the partial sectional view taken substantially along the lines III-III of FIG- URE 2, the prebreaking Zone 27 consists of a gradually outwardly tapered mouth 40 defined by the upper and lower defibering discs 41 and 42 respectively. The purpose of the the taper is to gradually and evenly break the over-sized chunks of beets and to cause them to be gradually thrown outwardly by centrifugal force. The entrance dimension 40a may vary from 0 inch to 4 inches. The spacing 46 between the bars at the exit portion of the prebreaking zone may vary from (l inch to 2 inches and is preferably in the neighborhood of 1 inch. The lower disc 42 is vertically adjustable with respect to the upper disc and the above dimensions 40a and 46 are representative with the lower disc in a midway position. The material leaves the prebreaking zone 40 as a homogeneous mass of fiber bundles with virtually no large chunks of material, the beet liber bundles enter into an intermediate material defibering zone 47. The zone 47 is defined by an intermediate annular portion 44 of the upper defibering disc and an intermediate annular portion 53 of the lower defibering disc. The opposed surfaces 48 and 57 of the upper and lower discs respectively are of a novel and special design so as to provide for adequate temperature control in order to avoid degradation of the cellulose fibers. It has been experimentally established that undesirable degradation of cellulose fibers occur in the presence of mechanical action if the temperature of the fiber mass is allowed to exceed about 180 C.

The intermediate defibering zone 47 allows the control of retention time of the fibrous beets in the intermediate zone due to special configuration of the annular chamber defined by the opposing surfaces 48 and 47. It will be noted that surface 57 gradually tapers away from surface 48 in a radially inward direction. More specifically, the surface 48 has a series of radially extending angularly spaced bars or ridges 71 thereon, best seen in FIG. 5. The bridges 71 define with the surface 48 a multiplicity of grooves which have been specifically designed to accomplish in addition to proper defibration and in cooperation with the lower disc surface 57, the functional temperature control and the control of retention time of the fibrous beets. The lower surface 57 is shown in detail in FIG. 5. It will be noted that the Surface 57 has a multiplicity of bars 72 thereon thus providing a series of grooves and ridges which are of generally coarser configuration than the grooves and ridges of surface 48 of the upper disc 41. More specifically, the width 73 of the groove 74 is in the neighborhood of approximately 3/16 to 1/2 inch and the 4width 75 of the ridge 72 in the neighborhood of 3/16 to l inch as indicated in FIGURE 5 which shows the coarse intermediate zone of the lower disc 57. The intermediate defibering section of the upper stationary disc 48 is of substantially finer design and more specifically, the width 76 of the groove 78 is preferably in the neighborhood of .125 to .250 inch, while the width 77 of the ridge 71 is preferably in the neighborhood of .095 to 0.20 inch. It will thus be seen that there is provided an intermediate defibering zone in which the bars of the upper stationary plate are spaced substantially closer together and are of substantially smaller Width than the opposing bars of the lower rotating defibering disc. In this manner, superior control of both temperature and retention time is achieved, because the amount of mechanical action of the fiber is substantially reduced While the fiber to fiber action of the fiber bundles is substantially increased. During the initial stages of operation, the grooves 78 and 74 of the upper and lower defibering discs respectively are filled up with fibrous beets which remain in the grooves during the operating life of the discs. With the grooves thus filled with the fibrous beets, opposing disc surfaces become relatively fiat, thus presenting to each other alternating surfaces of hard metal followed by resilient fibrous beets. A bundle of beet fibers traveling radially and circumferentially through the intermediate zone is thus subject to mechanical treatment between opposing fibrous surfaces. By increasing the width of the fibrous surfaces and the metal surfaces of the lower defibering dise approximately twice the width of the respective surfaces of the upper defibering disc it has been found that the fiber to fiber defibering action is substantially increased, while the metal to metal acion on the fiber bundle is substantially decreased. This advantageous result is in part due to the fact that the fiber bundles progress or roll faster between two opposed metal surfaces than between two opposed fibrous surfaces. The retention time between the opposed metal surfaces is thus substantially reduced. By providing the rotating disc 57 with a coarser pattern, an individual fiber bundle tends to travel with the rotating disc rather than adhere to the stationary disc 48, thus markedly increasing the defibering efficiency of the defibrator. As indicated in FIGURE 5, the resiliency of the fibrous beets in the grooves 78 and 74 of the discs 48 and 57 respectively, will cause the fibrous beets in the grooves to pulsate due to the operating fiuid pressure between the plates as the metal ridges 71 and 72 pass over their respective opposing grooves. For example, with the ridge 72 over the groove 78, the fibrous material 79 will be depressed, thus presenting a somewhat convex fibrous surface to the ridge 72. On the other hand, the concave surface will change to a convex surface 80 when one of the grooves 78 of the upper plate 48 is facing groove 74 of the lower disc 57. It should further be noted that the intermediate portion of the lower plate 42 has a surface 57 as shown in FIGURE 3, which gradually tapers outwardly, thus causing the cross-sectional area of the grooves and ridges 74 and 72 thereof to gradually decrease across a sectional area. Due to this gradual restriction in cross-sectional area of the grooves 74 and the ridges 72 of the lower plate 42, the fibrous beets will readily accumulate in the grooves in the initial operating period of the defibering device. The filling of the grooves with the fibrous beets will be further facilitated by the high consistency of the beet cossettes at which this device is designed to operate. The grooves of the upper stationary plate 41, however, are of substantially uniform cross-sectional area and in order to insure proper filling thereof with fibrous beets, there is provided a series of dams 49 in the grooves 78 so as to retain the fibrous beets therein.

From the intermediate zone 47, the partially defibered beets travel into a final defibering zone 50. As shown in FIGURE 3, the final defibering zone 50 is defined by an outer annular portion 45 of the upper delibering disc 41 and the outer annular portion 54 of the lower defibering disc 42. In the final defibering zone the temperature of the fibrous beets is maintained at approximately 140 C. The opposed surfaces 51 and 60 of the upper and lower discs respectively, are provided with a multiplicity of grooves and ridges of a special design which afford final defibering of the fibrous beets in such a manner that it is acceptable for the maximum expression of a sugar-containing liquid while retaining the proper beet fiber size for further use in plasterboard and other like material. The dimensions of the grooves and ridges of the upper defibering plate in the final defibering zone 45 are substantially equal to the dimensions of the grooves and ridges in the intermediate zone 44. It should, however, be noted in the final zone the ridges are of substantial constant heights or nearly so as are the ridges of the outer annular portion 54 of the lower plate 42. Depending upon the actual consistency of the fibrous beets, the final delibering zone may be somewhat tapered toward the outer periphery thereof. Generally speaking, the higher the consistency of the fibrous beets the lesser the taper will be. Such a taper may be machined or cast into the upper plate section 41 as well as into the lower plate section 42 or, alternatively, either one may be tapered while the other remains flat. Dams 49 and 59 are provided in the upper and lower plate section, in the grooves thereof, to retain the fibrous beets therein.

As the fibrous beets leave the final debering zone they will be thrown radially outwardly by means of impellers or blades, not shown, mounted to the outer peripheral surface of the lower defibering disc 42. The impellers or blades serve to force the discharged fibrous beets to a series of tangential exit ports 29, seen best in FIGURE 2, at a high velocity.

After the beet cossettes have been sufficiently defibered, they are passed through exit port 29 into the screw press, 1f desired, a pumping station (not shown) may be placed between the exit portion of the defibering mechanism and the entrance portion of the screw press, which will provide from about 5 to 10 p.s.i. pressure to the press, thus allowing better control of the amount of lpressure and time that the fiberilated beets are subjected to. Various types of presses may be employed, although a preferred form is shown in FIGURE 6. The pulp press shown is similar to the construction disclosed in U.S. Letters Patent No. 3,126,818, of which I am the inventor (which patent is hereby incorporated by reference), and comprises a frame plate 100 mounted on a conventional support structure such as I-beam or the like, suitably disposed in concentric spaced relationship about the plate which includes a bearing collar 111 having journalled therein the upper or neck portion 110 of a conical tapered extrusion spindle 113 generally disposed with a pefrforated cylindrical shell 114 suitably mounted at its upper end to the frame plate in depending relation therefrom. As will be understood, in accordance with the conventional practice, the shell is perforated to facilitate the passage of expressed sugar-containing liquid therethrough during extrusion of beet bers in the press on passage therethrough. The shell may form a screen for retaining the beet fibers during extraction and expression of sugarcontaining liquid from the beet fibers, or the shell may form a backing or perforated structural support for the motmting on its wall surface of a secondary screen 115 of Idesired mesh.

Surrounding the perforated shell 114 and depending in suitable securement from frameplate 100 is a cylindrical imperforated housing or casting 116 in coextension with the shell. Secured to the lower portion of the shell 114 and the housing 116 is a trough 117 defined by a conical annular wallplate 118 and a cylindrical wall portion 119 suitably secured together and to the shell 114 and the housing 116. Dependent from the trough 117 is a suitable skirt 120 for confining the discharge end of the press.

Rotatably mounted in spaced relationship with the shells 114 is a spindle 113, forming therebetween an eX- trusion chamber 121. The spindle 113 is supported in shell 114 by means of depending extension 122 rotatably journalled in the hydraulic chamber 123 of a hydraulic support 124, adapting the spindle for vertical adjustment and controlled movement by means of a desired variation of and control of pressure delivered to a hydraulic chamber 123 through an inlet 125. As may be seen from this illustration, the spindle is of conical or tapered configuration having its divergent end 126 disposed adjacent the discharge end of the press, thus forming a progressively conical larea in the extrusion chamber toward the discharge under the press. Fixedly mounted along the spindle 113 is an interrupted, or, if desired, continuous, helical or spiral flight arrangement 127 having in the embodiment illustrated interrupted threads or screw elements extending radially into close proximity with the inner wall of shell 114. The provision of the flight. arrangement 127 adapts the spindle for effecting movement of stock in the extrusion chamber to a discharge end 126 of the press on rotation of the spindle actuated by conventional mo tor means, not shown, suitably connected or geared to the neck portion of the spindle. To resist the rotation of the stock in the extrusion chamber the shell is provided with a plurality of projections or bars 128 which have downwardly angular surfaces and project internally therefrom into the extrusion chamber 121 intermediate the interrupted helical flight 127.

Accordingly, on rotation of the spindle, the threads of the flight arrangement 127 engage the beet fibers fed into the extrusion chamber 121 and force the beet fibers downwardly toward the discharge end of the press through progressively constructed annular area. defined between the spindle 113, and shell 114. Discharge of the material from the press is controlled by means of a choke cone mounted on the lower portion of spindle 113 in cooperating relationhip with conical wall 118 of trough 117. The feed or flow of the beet fibers into the extrusion chamber is accomplished by means of an inlet conduit 129 extending into the extrusion chamber through housing 116 and shell 114, with the removal of the sugar-containing liquid passing through the shell and collecting in the trough 117 effected by means of a discharge line 1230 connected into the trough. If desired, a pumping station may be placed in connection with inlet conduit 129 so as to maintain the screw press under positive pressure. It has been found that a pressure of between 2 to l5 p.s.i. and preferably between 5 to 10 p.s.i. will allow the maximum amount of sugar-containing liquid to be expressed from the beet fibers in the shortest amount of time.

The wet beet fibers being compressed are prevented from rotating with the spindle by resistor bars 128. Without the resistor bars the coefficient of friction of the beet fibers would not be adequate to prevent them from sliding on the shell surface. The resistor bars have an angular surface that tends to move the :material down as they resist the rotational force. As illustrated in FIGURE 6, the helical flight of the spindle is interrupted and overlap in order to allow the resistor bars to extend from the shell surface, close to the spindle body.

To eliminate and prevent binding of the shell due to lodging and accumulation of solid beet fiber thereon, a plurality ofy screened wiper blades 131 are mounted in helical spaced relationhip to each other along the threads or flight elements 127 adjacent the periphery thereof. Each of the wiper blades is of elongated configuration for longitudinal extension along the inner wall of the shell. The wiper blades are adapted for swinging movement on the thread or flight elements by means of a bifurcated projection forming lugs 132 for receiving the flight elements therebetween to which the wiper blade is pivotally mounted by means of a pin 133 extending through the lug holes in a suitable mounting hole provided in the flight element. Since the wiper blade is freely pivotable, it is thus adapted for swinging movement against the shell 114. Preferably to provide for optimum clearance between the spindle assembly and the shell; the flight element may be suitably notched to accommodate retraction of the wiper blades therein. The wiper blade is actuated by the beet fibers which force the blade against the shell, thereby cleaning the shell of solid beet fibers and preventing accumulation of the fiber thereon by removing and shearing the particles lodged or deposited on the shell.

Also, as illustrated in FIGURE 6, the screw press is adapted for increased extraction of liquid from the stock by forming the spindle with an upper portion 134 and a lower portion 126. The upper portion is provided with a tapered conical configuration having the convergent end thereof disposed adjacent the inlet of the press with its peripheral surface longitudinally defining a downwardly converging angle with the inner wall of the shell. The

lower portion 126 is provided with a configuration having a peripheral surface extending longitudinally parallel with the shell to form a uniform angular extrusion chamber of substantial length, This parallel relationship between the shell and the lower spindle portion prevents further radial compression of the extruded stock to maintain the material in an optimum thickness to keep the radial drain channels therein open for continuing flow of expressed fluid therethrough.

The resistor bars or projections 128 may be provided with the openings therethrough (not shown) and connected through suitable couplings, tubes and the like to heating fluids, such as steam, which may be injected during the operation of the press to the beet liber to facilitate the removal of the sugar-containing liquid. The beet fibers are heated to a range of 50 to 65 C. Heating of the beet fibers is especially desirable in the second press after the beet sugar has been leached in the aqueous washing tank. Any desired number of presses and washing tanks may be coupled together to form a battery of presses so as to render the sugar in the discharge beet pulp approximately 0.1 to 1.0 percent.

The granulator 12 described in FIGURE 1 may be similar in construction to the defibering device described in FIGURES 2, 3, 4 and 5 except that the dimensions of the grooves and ridges would be of finer dimensions as would the spacing between the upper and lower defibering disc. This reduction in scale would tend to increase the temperature in the operational stages of the granulator, thus allowing for further drying of the sugar prior to being screened and packed.

As shown in FIGURE '7, the beet chipper is similar to the construction disclosed in U.S. Letters Patent 2,951,518 (which patent is hereby incorporated by reference) and comprises a rotary cutter head 200, a chute 202 through which beets are fed to the cutter head from a suitable platform, not shown. The beets are propelled to the cutter head by means of a rotor 204 having lingers 206 projecting through slots (not shown) in the ramp 207 constituting the bottom of the chute. A set of detents 211, 212 and 213 are pivotally mounted on a shaft (not shown) for holding the beets against retrograde movement. A suitable stop is placed on the frame below the detents but above the furthest reach of the fingers 206 to limit the downward movement of the detents; as this stop may be arranged `in any desired shape or form it is not illustrated, but workers skilled in the art are aware that almost any type of stop may -be employed, as for example an angle bar. Disposed over the chute is a cover 216 which is mounted on a shaft common to the detents, the cover resting on the side of the chute by gravity and preferably being weighed to restrain the beets from riding up on each other. The cover 216 is provided with slots 217 through which the noses of the detents 211, 212 yand 213 extend.

At the end of the chute adjacent the cutter head is an extension 221 secured by bolts 222. Under the extension is an adjustable support comprising a Ibed plate 223 extending the full width of the chute, the plate being mounted on support 224 which may be pivotally mounted on a suitable frame. The bed plate 223 is preferably formed of soft metal and is detachably mounted with screws 227 so as to be replaceable. Plate 223 may be provided with screws or other such device to control the extent of adjustment to which the plate 223 extends be yond the end of extension 221, so that the edges of plate 223 can be accurately adjusted in very close proximity to the path of the cutting edge on head 200.

The cutter head 200 is mounted on a shaft 232 which 1s generally mounted in a suitable bearing. Mounted in recesses in the periphery of the cutter head by means of screws 234 and clamping plates 236 are knives 237. A characteristicfeature of the knives consist in the outer end or peripheral faces 238 being substantially concentric with the axis of the cutter head, instead of having clearance as usual. Thus the knives may be grounded while mounted on the head by rotating the head past the grinder. However, the principal `advantage of this feature is that the knives cut thin uniform chips without the tendency to dig into the beets because the peripheral surface of the. cutters, having no clearance, resist the advance of the beets and prevent the beets from being pulled into the cutters. This feature also contributes largely to the markedly uniform size chips and beet fibers obtained therefrom, which uniform size greatly facilifates the removal of a maximum amount of sugar juice therefrom. The front faces of the knives 237 may be provided with suitable grooves to divide each chip into ribbons whose widths are equal to the grooved internals, one side of each groove `being approximately perpendicular to the face of the cutter and the other side being inclined and extending only part way toward the next groove. In as much as the entire cutting edge is at the same distance from the axis of the cutting head, each chip is of uniform thickness throughout the length of the cutter, notwithstanding the grooves which merely serve to divide the chips into ribbons. The relationship between the location of the grooves in the successive knives is not important because the knives leave smooth cuts without producing substantial waste.

The chute 202 may be pivotally mounted on a stationary frame, .if desired, so that the entire chute may be swung counterclockwise to give access to the parts beneath the chute.

The feeding rotor 204 is mounted on a suitable shaft which is journalled in suitable bearings to `allow rotation of the rotor, the shaft and bearings not being shown as they are well known in the art. The fingers 206 are spaced apart far enough to receive a beet between each pair of successive fingers. The bottoms 248 of the recesses between the fingers `are preferably spaced from the -axis of the rotor approximately the same distance as the ramp at the location along the ramp nearest to the axis. The front faces of the fingers which engage the beets :are approximately radial from their inner end throughout a distance somewhat more than one-half the average diameter of the beets and then the faces curve rearwardly. In order to obtain uniform feed as the fingers retract from the beet chute the curvature of the faces of the outer ends of the fingers are preferably involute based on a circle with a diameter approximately three times the diameter of the beets. Except for this curvature, the fingers would tend to accelerate the beets as they slide under the beets owing to the fact that the points of engagement between the fingers and the beets gradually move outwardly from approximately the middle of the fingers to their outer tips. By virtue of the involute curvature this tendency is counteracted. It is understood, of course, that while I have described the ridges 206 as fingers, they in fact extend the entire length of the 13 chipping mechanism and are in reality ridges forming trough-like openings therebetween.

V As the fingers slide under the beets, the rate of feed gradually decreases if the ramp 207 is straight, this being ydue to the fact that, owing to the curvature of the beets the points of engagement between the fingers and the beets gradually advance along the lower side of the beets. By -making the ramp circular on a diameter nine times the diameter of the beets this tendency is counteracted.

In operation, beets roll down from a suitable platform between successive fingers into the trough therebetween so that looking perpendicularly to the machine, i.e., endwise, only one beet is picked by each pair of fingers. However, it is understood, of course, that a number of beets are in this trough if one were to look in the machine direction. After being picked up by the fingers, each beet is `first advanced into contact with the next proceeding beet after which it pushes the preceding beet ahead. When eachpair of fingers reaches the position occupied by the fingers 206 in FIGURE 7, the tips of the fingers pass under the beet, and the detents 211, 212, 213 hold the beets against the retrograde movement. In the illustration the spacing of the fingers is such that the distance 251 :between the beets is approximately one-half the diameter of the average beet, `in which ease beets are fed to the cutter head intermittently with the feed intervals about twice the re-st intervals. Because of the aforesaid curvature of the fingers and the spacing therebetween, only one beet is received in each recess between the ffingers, or troughs, the next beet being pushed back by the curved finger tips. As illustrated, the spacing is preferably such that one or `more beets are interposed between the one being cut and the one being pushed by the feeder, so that there is somecompression of the series of beets, this compression being maintained by the detents 211 to 213 while a new beet is being brought up. The new beet does not begin to push the preceding series until the fingers start to retract to the ramp and the points of engagement between the fingers and beets are on the curved portion of the fingers.

By feeding the beets at uniform speed and using knives without clearance,rchips of uniform thickness are produced without a tendency for the knives to dig into the beets and produce non-uniform thicknesses. The thickness of the chips depend upon the relative speed of the cutter head and feed rotor, it of course being understood that the cutter head 200 and rotor 204i are synchronized so that the speed ratio remains constant, except for adjustments for different chip thicknesses.

An important feature of the machine consists in the adjustability of support 224 so that notwithstanding wear, the clearance between the knives and the bed plate 223 can be kept at a minimum, thereby preventing waste, in the form of splinters, fines, etc. from breaking olf at the end of each cut. By making the bed plate of soft metal, the adjustment may be made While the machine is running without danger of damage to the knives.

The circumferential dimension of the heel, that is the peripheral face of each blade, should bear a certain relationship to the spacing of the blades, depending upon the thickness of the chips desired, For example, in making chips of a thickness in the order of 0.025 inch, the ratio may be in the order of from 1:10 to 1:20 with a heel of 0,6 inch to 0.3 inch.

FIGURE 8 is a diagrammatic showing of the pump system illustrated in FIGURE 1 as feeding the defbered beets into the vertical presses and keeping the pressing, leaching, and purifying steps of the sugar treatment process under positive pressure and sealed from atmospheric conditions. This type of installation may be automatic or semi-automatic in operation and its prime purpose is to allow for a completely enclosed system. Obviously it can only be used where the feed is pumpable. It has been found by experimentation that the maximum pumpable consistency or percent of solids is in the range of 5 to 20%. For maximum capacity at any given press spindle speed, the press must remain filled at all times. Normally a head of at least five feet above the inlet should be used for satisfactory performance, giving an effective pressure on material at the upper flights of the auger less than l p.s.i. With a pressure feed system, inlet pressures can be achieved of 5 to l0 p.s.i.--which would be equivalent to a head of l2 to 25 feet, which is almost impossible to obtain in any standard installation. The increase in pressure takes better advantage of the upper portion of the screened area in the vertical press and will extract a maximum amount of the moisture. Since dewatering in a screw press is primarily a time-pressure function, additional head pressure, in effect, extends the spindle and screen area. It has been found by experimentation that in most applications press capacity has been increased from 15 to 30% depending upon the type of material being used.

yIn a typical pressure feed system, as illustrated in FIG- URE 8, the defibered beet stock is pumped from a chest or hopper to the press. The pressure switch at the press inlet detects and controls the pressure. If pressure exceeds a setting, the switch automatically opens a rubber or diaphragm-type valve relieving the pressure by allowing excessive material to flow back to the chest or hopper.

In a completely automatic system, the level in the chest or hopper feeding the pump would act as a control. A rising level would be sensed and the variable speed drive on the press would be increased to handle the surge. A level drop would also be sensed and the variable speed drive on the press would be slowed down to compensate for the reduced amount of beet stock. With this type of pressure feed system, the possibility of overflow of the press is completely limited and, therefore will minimize normal housekeeping problems.

Although the invention has been described with reference to specific materials, embodiments and details the various modifications and changes within the scope of this invention will be apparent to one skilled in the art and are contemplated to be embraced within the invention.

I claim as my invention:

1. A process for treating sugar beets comprising: (l) chipping whole sugar beets into substantially uniform thin beet chips; (2) defibrating the beet chips into substantially uniform distinct beet fibrils; (3) pressing the beet fibrils without addition of foreign liquids to separate spent beet fibrils from sugar-containing beet juice; (4) purifying the expressed sugar-containing beet juice; and (5) removing granulated sugar from the expressed sugar-containing beet juice.

2. A process of treating sugar beets in accordance with claim 1 wherein step (l) includes introducing whole beets into a beet chipper comprising a rotary cutter head, means for guiding beets to the head along a path which approaches the head approximately radially with whole beets extending perpendicularly to the axis of the head, means for positively feeding said beets` along said path, and slicers mounted on the periphery of the head at spaced locations around the head having a cutting edge extending lengthwise of the head with outer ends concentric with said axis so that there is no clearance behind said edge thereby to slice thin chips of uniform thickness throughout their area; and step (2) includes introducing the beet chips into a continuously vented distributing zone whereby the beet chips are uniformly distributed throughout a continuously vented prebrleaking zone, continuously feeding the prebroken beet chips to a continuously vented initial defbering zone defined by opposed close running attrition surfaces whereby the prebroken beet chips are subject to mechanical rubbing and rolling action under controlled conditions of temperature and pressure, continuously feeding the initially defibered beet chips to a final deiibering zone defined by the outer portion of said close running attrition surfaces and spaced radially outwardly therefrom whereby the individual undeveloped fibers are subject to abrasive action to fibrilate and soften the prebroken beet chips.

3. A process of treating sugar beets in accordance with claim 1 wherein step (3) includes: (a) continuously feeding the fbrilated beet chips to a vertical screw press; (b) continuously feeding the initially pressed fibrilated beet chips to an aqueous leaching tank; (c) continuously feeding the wet brilated beet chips to a second vertical screw press; said first and second screw press comprising a perforated cylindrical shell having an inlet adjacent one end thereof and a discharge end adjacent the opposite end thereof, a spindle coaxially mounted in spaced relationship with said shell and comprised of a first spindle portion and a second spindle portion, said first spindle portion being of tapered conical configuration having the convergent end thereof disposed adjacent the inlet of said press with the peripheral surface of said first spindle portion longitudinally defining an angle with the inner wall of said shell, said second spindle portion forming a continuation of said first spindle portion from the divergent end thereof and having a peripheral surface extending longitudinally parallel with the inner wall of said shell toward the discharge end of said press, a helical flight arrange- -ment fixedly mounted along said first and second portions of said spindle with threads of said flight arrangement extending radially into close proximity with said inner Wall of said shell, motor means for imparting rotary movement of said spindle relative to said shell to move the f fibrilated beet chips toward a discharge end of said press, and liquid gathering means disposed externally of said shell for collecting liquid passing through said shell externally therethrough.

4. A process of treating sugar beets which comprises: (1) chipping whole sugar beet into substantially uniform thin beet chips; (2) defibrating the beet chips to form distinct beet fibrils; (3) continuously pressing said beet fibrils without addition of foreign liquids to remove 50% to 85% sugar-containing beet juice therefrom; (4) continuously feeding the initially pressed beet fibrils to a heated aqueous leaching tank to add about 80% to 90% aqueous leaching solution to the pressed beet fibrils; (5 continuously feeding the leached beet fibrils to a pressing station to remove 80% to 90% sugar-containing liquid therefrom; (6) repeating steps (4) and (5) until the sugar content of the leached beet fibrils is below 1.0%; (7) purifying the expressed sugar-containing liquids; and (8) crystallizing sugar from the expressed sugar-containing liquids.

5.'A process of treating sugar beets which comprises: (1) introducing whole beets into a beet chipper comprising a rotary cutter head, means for guiding beets to the head along a path which inclines upwardly and which approaches the head approximately radially with the Whole beets extending perpendicularly to the axis of the head, means for feeding beets along said path positively and individually and slicers mounted on the periphery of the head at spaced locations around the head, said slicers having cutting edges extending lengthwise of the head and whose outer ends are concentric with said axis so that there is no clearance behind said edges to slice thin chips of uniform thickness throughout their areas; (2) introducing the beet chips into a continuously vented distributing zone whereby the beet chips are uniformly distributed throughout the continuously vented prebreaking zone, continuously feeding the prebroken beet chips to a continuously vented initial defibrating zone defined by opposite close running attrition surfaces whereby the prebroken beet chips are subject to mechanical rubbing and rolling action under controlled conditions of temperature and pressure, continuously feeding the initially defibered beet chips to afinal defibering Zone defined by the outer portions of said close running attrition surfaces and spaced radially outwardly therefrom whereby the individual undeveloped fibers are subject to abrasive action to fibrilate and soften the prebroken beet chips to produce distinct beet fibrils; (3) continuously feeding beet fibrils under a pressure in the range of 5 to 15 p.s.i. to a battery of screw presses, ach press comprising a perforated cylinder having an inlet adjacent one end thereof and a discharge end adjacent the opposite end thereof, a spindle co-axially mounted in spaced relationship with said shell and comprising a first spindle portion and a second spindle portion, said first spindle portion being of a tapered conical configuration having the convergent end thereof disposed adjacent the inlet of said press with the peripheral surface of said first spindle portion longitudinally defining an angle with the inner wall of said shell, said second spindle portion forming a continuation of said first spindle portion from the divergent end thereof and having a peripheral surface extending longitudinally parallel with the inner wall of said shell toward a discharge end of said press, a helical flight arrangement fixedly mounted along said first and second portion of said spindle with threads of said flight arrangement extending radially into close proximity with said inner wall of said shell, said helical flights being composed of a plurality of interrupted spiral flights arranged to balance one another, a plurality of resistor bars having downwardly angular surfaces mounted inwardly from said cylindrical shell and having interior passage therein for the conductance of heating fluid to the beet fibrils to heat said beet fibrils to a temperature in the range of 50 to 65 C., motor means connected to said spindle portions for imparting rotary movement to said spindles relative to said shell to move the beet fibrils toward a discharge end of said press, and liquid gathering means disposed externally of said shell for collecting liquid passing externally through said shell (4) continuously feeding the initially pressed beet fibrils to an aqueous leaching tank where the moisture content of said beets is raised to to 90%; (5) continuously feeding the re-wetted beet fibrils to said battery of screw presses to render the final pressed beet fibrils in a dry form containing from 5% to 15% moisture and from 0.1% to 1.0% of the original sugar content; (6) purifying the expressed sugar-containing beet juice; (7) crystallizing sugar from the expressed sugar-containing beet juice; (8) washing and drying the crystallized sugar; (9) granulating the dried sugar crystals; and (l0) screening and packing the granulated sugar.

References Cited UNITED STATES PATENTS 2,332,062 10/1943 Cutler 127-3 X 2,775,191 12/1956 Youd 100-112 2,951,518 9/1960 Cumpston 144-172 3,035,511 5/1962 Hayes 100-117 3,126,818 3/1964 Koelsch 10U-"112 3,387,796 6/1968 Cormack et al. 241-43 MORRIS O. WOLK, Primary Examiner SIDNEY MARANTZ, Assistant Examiner U.S. Cl. X.R.

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