WO1993016794A1

WO1993016794A1 - Improved apparatus and method for extraction of juice from sugarcane pith

Info

Publication number: WO1993016794A1
Application number: PCT/US1992/000039
Authority: WO
Inventors: Sydney E. Tilby
Original assignee: Tilby Sydney E
Priority date: 1992-02-21
Filing date: 1992-02-21
Publication date: 1993-09-02
Also published as: AU2642992A

Abstract

An apparatus (60) for continuous-process extraction of juice from substantially rind-free sugarcane pith (66) has a pith supply and a tank (71) with an extraction assembly (86) therebetween. The assembly (86) includes a rotatable perforated member (81) and a rotatable, resilient compression member (83). The rotatable members (81, 83) receive and squeeze pith (66) from an input region (85) of supply and press juice through perforated member (81) into the tank (71). Preferred embodiments include a rotatable pre-compression feed roll (129), preferably with radial projections (133), for pre-compressing pith (66) and extracting an amount of juice and for urging pith (66) in input region (85) toward extraction assembly (86) for more complete juice extraction.

Description

Title: IMPROVED APPARATUS AND METHOD FOR EXTRACTION OF JUICE FROM SUGARCANE PITH

Field of the Invention

This invention is related generally to apparatus for processing sugarcane to extract juice therefrom and, more particularly, to apparatus for extraction juice from the sugar-rich pith portion of the sugarcane plant after it has been separated from the sugarcane rind..

Background of the Invention

General Background

The stalk of the sugarcane plant includes an outer rind which is a hard, wood-like fibrous substance. The rind surrounds a central core of pith which bears nearly all of the sugar juice from which various sugar products are made. The outer surface of the rind has a thin, waxy epidermal layer, referred to herein as "dermax." Certain other plants (for example, sweet sorghum) are similar to sugarcane in that they are grasses having woody grass stalks. While there is frequent reference herein to sugarcane, it is to be understood that this invention applies to processing of woody grass stalks like sugarcane and sweet sorghum or certain of their constituents. At no point, including the claims, is any reference to sugarcane to be limiting.

Conventional sugarcane industry practices until today have utilized sugarcane primarily only for its sugar content. Such industry practices have involved chopping and crushing sugarcane stalks to remove the sugar juice, with the waste solids (bagasse) being used primarily only as fuel, mainly in sugar production operations.

Although such practices have been virtually uniform throughout the industry, it has been recognized that a number of very useful products may be produced from sugarcane if the sugarcane stalk is first separated into its rind, pith and dermax constituents. The many useful end products made possible by such separation can provide great economic benefit. Such separation also provides significant efficiencies in the production of sugar.

Earlier efforts involving stalk separation, though not necessarily related to sugarcane, are reflected in the following United States patents:

605,293 (Madden)

608,630 (Wright)

616,177 (Adelsperger) 623,753 (Winchell)

623,754 (Winchell)

627,882 (Sherwood)

632,789 (Re y)

657,341 (Dyer) 670,037 (Sherwood)

675,758 (Sherwood)

684,492 (Adamson)

707,531 (Adamson)

1,689,387 (Heimlich) . 2,706,312 (Bobkowiczj . Even though stalk separation efforts began as early as the late 1800"s, essentially the entire sugarcane industry continued in the conventional process noted above, involving chopping and crushing of the whole, stalk to extract sugar juice. An example of such approach is shown in United States Patent No. 4,043,832 (Leibig et al.). As feedstock, the Leibig et al. apparatus uses entire cane stalks which have been fiberized. The fibrous bed of material is compressed between rigid rolls, one perforated and one imperforate with chevron¬ like ridges thereon. Another example using entire cane stalks is apparatus shown in United States Patent No. 3,697,324 (Steele et al.). Such apparatus similarly uses a perforated lower roll and has a pivotably mounted, container-like upper roll which can be filled with liquid to provide additional compression force. Yet other examples are shown in United States Patent Nos. 3,695,931 (Hamill) and 3,818,824 (Kloda et al.). The apparatus shown in the Kloda et al. patent uses several rollers in sequence to remove juice from crushed cane stalk.

A disadvantage of the foregoing apparatus is that the feedstock is rarely of uniform thickness along the length of the "nip" between the compression rolls. Therefore, feedstock compression force and resulting juice extraction are not often uniform along the nip. Technology in this field remained rather dormant until the 1960's when a resurgence of development activity began, substantially all related to what has been known in the industry as the Tilby system, a cane separation system named after the principal originator, Sydney E. ("Ted") Tilby.

Broadly speaking, the Tilby system includes a multi-step operation executed by various portions of a cane separator machine. Sugarcane billets, that is, cut lengths of cane stalk preferably about 25-35 cm long, are driven downwardly over a splitter to divide them lengthwise into semi-cylindrical half billets. The two half billets of a split billet are then processed individually by symmetrical downstream portions of the separator machine.

The first of such downstream portions of the separator is a depithing station which includes a cutter roll and holdback roll for milling pith away from the rind of the half-billet while simultaneously flattening the rind. The next downstream portion is a dermax removal station from which the rind emerges ready or subsequent processing in a variety of ways, including slitting, chipping and/or many other processing steps. The pith is conveyed away from the separator machine to an extraction station where its sugar juice is removed.

A significant number of patents related to the Tilby system and improvements in such system have been granted, beginning in the 1960's. These and other fairly recent United States patents related generally to sugarcane processing are as follows:

3,424,611 (Miller) 3,424,612 (Miller) 3,464,877 (Miller et al.) 3,464,881 (Miller et al.) 3,566,944 (Tilby) 3,567,510 (Tilby) 3,567,511 (Tilby) 3,690,358 (Tilby) 3,698,4.59 (Tilby) 3,721,567 (Miller et al.) 3,796,809 (Miller et al.) 3,873,033 (Tilby) 3,976,498 (Tilby) 3,976,499 (Tilby) 4,025,278 (Tilby) 4,151,004 (Vukelic) 4,312,677 (Tilby et al.) 4,572,741 (Mason) 4,636,263 (Cundiff) 4,702,423 (Pinto) 4,743,307 (Mason) 4,816,075 (Gruenewald) . The Tilby system, when finally fully commercialized, can provide substantial outputs of several high-value products. This greatly increases cash yields per ton of sugarcane, a factor of significant importance to an industry in which profitability in recent years has been marginal at best. This is important generally, but is of particular importance to the many developing countries in which a flourishing sugarcane industry would be a boon to economic growth and stability. Considering that sugarcane is one of the most rapidly growing, easily developed, and readily accessible sources of biomass, full commercialization of the Tilby system can significantly reduce dependence on forests and on certain other crops and resources. Among the products which can be made from sugarcane constituents separated by the Tilby system are sugar in an increased variety of forms, foods and food additives, animal feeds, a variety of wood products and building materials, alcohol for a variety of purposes, paper and other pulp-containing products, and a variety of specialty products.

While substantial technical development has occurred over a period of many years with respect to the Tilby system, a number of difficult and critical problems have remained. The failure to overcome such problems has prevented full commercialization of the Tilby system.

The invention described and claimed herein is directed to the solution of certain of these problems.

Specific Background One problem relates to extraction of sugar juice from pith which has been separated from the sugarcane stalk. A variety of approaches have been suggested for such extraction, but none of these has been established as a commercially-viable approach for a high-throughput operation. Before beginning a more specific discussion of the problems related to extraction from separated pith, reference is made to certain disclosures in addition to those noted above. The following United States patents provide additional background with respect to extraction:

395,145 (Hughes)

471,995 (Gschwind)

757,296 (Gibbens et al.)

1,700,571 (Milne) 2,227,605 (Swallen et al.)

2,567,474 (Fitts et al.)

3,693,540 (Dambrine) .

One approach for extraction of juice from separated pith has been to utilize equipment like that used to extract sugar juice using the entire crushed stalk as feed stock. Such equipment includes pairs of imperforate rotating grooved metal cylinders between which feed stock is squeezed in the presence of liquid. Such equipment is particularly useful when the feed stock is of entire crushed stalks, but is less than successful when the feed stock is separated pith.

In the former case, pith cells are usually unbroken as the feed stock enters the extraction equipment, and many cells are not broken by such equipment because the presence of rind and the equipment design provide spaces in which such unbroken cells are protected, despite the extreme pressures which are applied. In fact, a good deal of the extraction which occurs in such situations involves a leaching in which sugar passes through the cell walls to the surrounding liquid which has a lower sugar content.

It suffices to say that when the feed stock is separated pith, rather than crushed stalk, the user is faced with a different set of concerns. For one thing, pith does not always feed into such old-style equipment properly. Nor does such equipment provide a sort of squeezing which is appropriate for removal of juice from pith cells which are already ruptured before entering the extraction equipment. In Tilby-system separation equipment, rupturing of most pith cells occurs at the depithing station. The old-style equipment is built to apply enormous extraction pressures between cylinders due to the nature of the feed stock for which they were designed. The extraction techniques of the old-style equipment are simply inappropriate for extracting juice from separated pith. Other approaches which have been disclosed include additional continuous-process equipment and some equipment using batch processing. All of the prior devices has shortcomings or problems which make them unsuitable for continuous high-throughput commercial extraction of sugar juice from separated pith.

Among the prior approaches are those disclosed in United States Patent Nos. 4,101,285 (Tilby) and 4,230,733 (Tilby) . The '285 Tilby patent discloses a basket-like arrangement involving leaching and optional squeezing of the pith. The '733 Tilby. patent discloses a reciprocating plunger with perforated ends to squeeze the pith and extract juice. These extraction devices, like others, are unsuitable for large-scale continuous operations. An improved apparatus for continuous extraction of sugarcane juice from juice-bearing pith would be an important advance in the art.

Objects of the Invention It is an object of this invention to overcome some of the problems and shortcomings of the prior art.

Another object of this invention is to provide an improved juice-extracting apparatus suitable for use in a continuous process. Another object of this invention is to provide an improved apparatus for extracting sugarcane juice suitable for use in a high-throughput operation.

Another object of this invention is to provide an improved apparatus for extracting sugarcane juice wherein extracting pressures are selected for use with separated, ruptured pith cells.

Yet another object of this invention is to provide an improved apparatus for extracting sugarcane juice wherein the apparatus provides for proper feeding of pith from which juice is to be extracted.

Still another object of this invention is to provide an improved apparatus for extracting sugarcane juice wherein the apparatus extracts juice from pith which may be unevenly distributed between the extraction rolls.

These and other important objects will be apparent from the descriptions of this invention which follow.

Summary of the Invention In general, the improved apparatus for continuous- process extraction of juice from sugarcane pith comprises means for holding a supply of substantially rind-free sugarcane pith, a tank for receiving liquid and an extraction assembly between the holding means and the tank. The extraction assembly has a rotatable perforated member and a rotatable resilient compression member, both of which are positioned and arranged to receive pith from an adjacent input region and squeeze such pith to extract the sugar-bearing juice from it. Such juice flows through the perforated member, into its interior cavity and through openings in a lateral wall to the tank.

In a highly preferred embodiment, the compression member and the perforated member are cylindrical and driven for rotation in opposite directions about substantially parallel first and second axes, respectively. The compression member has an outer portion which is resilient and adjacent to the perforated member. This outer portion is of a thickness and resiliency to receive and compress a mass of pith to extract juice from it, even though such mass may be somewhat unevenly distributed along the nip of the rolls.

The extraction apparatus further includes urging means adjacent to the input region for pre-compressing pith in the input region and preliminarily extracting juice therefrom. The urging means, which can be rigid or resilient, also helps move the partially-squeezed pith toward the extraction assembly. Preferably, such urging means includes a rotatable feeder member having radial projections arranged thereon to move pith along the input region toward and into the extraction assembly. The feeder member, which is generally cylindrical, rotates about a third axis substantially parallel to the first and second axes. Preferably, the feeder member is pivotably mounted so that the locus of its axis of rotation can be adjusted to accommodate variations in the wetted pith fed into the extraction apparatus.

The projections, substantially smooth half-cylinder shaped elements, extend along the length of the feeder member and are spaced about its circumference. Expressed juice from the squeezed pith flows through the holes in the perforated member and into a tank below.

After being squeezed, much of the pith "scours" cleanly from the perforated member and can readily be conveyed away for subsequent processing. However, a certain amount tends to stick to its outer surface. Therefore, a highly preferred embodiment of the extraction apparatus further includes means for removing adhering pith from the perforated member following compression and means for conveying such compressed pith for subsequent processing. The removing means may include a doctor blade on the perforated member to help scrape away pith which adheres to such member. The perforated member has a lower portion situated in the tank whereby pith still adhering to such member may be immersed in liquid to rewet it, thereby aiding in its removal. Further removal of sticking pith is by means contacting the perforated member in a position after immersion thereof to brush rewetted pith from such member. The extraction apparatus also includes means such as a weir associated with the tank for separating solids from liquid as both collect in the tank. Such apparatus also includes means such as a pump and conduit to recycle liquid from the tank to the holding means.

Brief Description of the Drawings

FIGURE 1 is a representative side elevation view, with portions removed, of a sugarcane juice-extracting system. FIGURE 2 is a representative side elevation view, with portions removed, of one of the extractors shown in the system of FIGURE 1.

FIGURE 3 is a perspective view showing a partially-disassembled perforated member. FIGURE 4 is an enlarged cross-sectional view taken along the viewing plane 4-4 of FIGURE 3 and showing a portion of the perforated drum used in the perforated member. Such viewing plane is parallel to the end of the drum. FIGURE 5 is an elevation view of the compression member with portions broken away.

FIGURE 6 is a perspective view of the urging means shown in FIGURES 1 and 2. Detailed Descriptions of Preferred Embodiments

The improved apparatus 60 is used in a continuous process, a portion of which involves the extraction of sugarcane juice from cane pith. Such process is carried out by an integrated system which receives cane as harvested from the field and, finally, delivers sugar-juice and other useful products.

The extracting system 61 shown in FIGURE 1 forms only a portion of such integrated system and as its "feedstock" uses pith 66 which has prior been milled from half-billets of cane. Such milling operation fractures a high percentage (about 95%) of the juice bearing pith cells, thus permitting juice to be extracted using much lower compressive pressures than in earlier systems. And since most pith cells are fractured, such system 61 is much less reliant upon the extraction of juice by leaching or diffusion through an unfractured cell wall.

Extracting system 61 includes a plurality of extractor apparatus 60 arranged in sequence and followed by a de-watering station 62 which extracts about 50% of the water from the spent pith. While three extractor apparatus 60 are shown, this is merely exemplary and a fewer or greater number of apparatus 60 may be used. However, the use of three apparatus 60 and a de-watering station 62 removes about 99% of the sugar-juice from the pith. Further, it is to be appreciated that water can be removed by means other than a de-watering station 62, for example, by an evaporator. However, a compression type dewatering station 62 is very economical for the purpose. In system 61 shown in FIGURE 1, sugarcane pith moves "downstream" from left to right and the sugar-bearing juice flows "upstream" from right to left, finally being removed from first extractor apparatus 60 via pipe 63. A brief overview of the operation of system 61 will be helpful in understanding the following detailed description. Fresh, substantially rind-free sugarcane pith 66, rich in sugar-juice, is fed to first apparatus 60 by a drag conveyor 64 followed by a leveler 65 of the type using a shaker or leveling forks. Drag conveyors are preferred for use in system 61 since they can be operated more slowly than a conventional belt conveyor and since they include a watertight conveyor trough 67 for liquid containment. Liquid is thereby better able to soak into pith 66 as it moves along, improving sugar- juice extraction. And when the ribbon-like mass of pith 66 is generally level along its width, squeezing extraction of juice from the entire mass is improved. Wetted, generally leveled pith 66 is directed into a holding means 69 such as a chute 69a. There it is mixed with recycled liquid flowing through a conduit 70 from tank 71. It is also mixed with liquid drawn from tanks 71a, 71b, 71c located at the next successive apparatus 60 or at de-watering station 62, as the case may be. The latter liquid from tanks 71a, 71b, 71c is delivered through pipe 72.

Wetted pith 66 enters an extraction assembly 60 where it is squeezed between a perforated member 81 and a compression member 83. Sugarcane juice flows through holes in perforated member 81 and downward to a liquid receiving tank 71. Squeezed pith is deposited to an inclined conveyor 64 and directed to next successive apparatus 60. At de-watering station 62, spent pith (that from which sugar juice has been substantially entirely extracted) is transported out of system 61 by a conveyor 84 for possible further processing into flour, for example. Recovered juice flows through pipe 63 to equipment which recovers sugar, sweetener concentrates^' or the like therefrom. Referring next to FIGURE 2, it should be noted that illustrated apparatus 60 is devoid of a leveler 65 which is used only with first apparatus 60. Once leveled, mass of pith 66 generally remains so as it moves through system 61.

Apparatus 60 includes a holding means 69 such as an open, angularly-inclined chute 69a. Wetted pith moves down chute 69a to input region 85 and into extraction assembly 86. A tank 71a receives liquid which is squeezed from wetted pith 66 and which flows through holes 117 in perforated member 81.

Extraction assembly 86 is between holding means 69 and tank 71a and in a highly preferred embodiment, members 81, 83 are in contact with one another and coact to receive wetted pith 66 from input region 85 and squeeze it for juice extraction. Compression member 83 and perforated member 81 are each cylindrical in shape and driven to counter-rotate about a first axis 95 and a second axis 97, respectively. These axes 95, 97 are substantially parallel to one another and since mass of incoming pith is of generally uniform thickness, extractive force exerted by members 83, 81 on pith is generally uniform along length of members 83, 81. Members 83, 81 may or may not have same diameters. In latter event, rotational speeds of members 83, 81 are selected so that their linear speeds are substantially equal.

Wetted pith includes relatively fine, light fluffy particles of sugarcane pith. Such mixture is not "stringy" like conventional crushed cane in which strands of cane rind enter a nip and tend to pull upstream mixture along with it. Accordingly, improved apparatus 60 also includes urging means 98 adjacent to and spaced somewhat above input region 85 for pre-compressing pith to a smaller volume, initially extracting an amount of juice therefrom and urging pre-compressed, partially expressed pith 66 toward extraction assembly 86. Further details on such urging means 98 are set forth below. Referring additionally to FIGURE 3, perforated member 81 includes a support frame 101 having a pair of disk-shaped lateral walls 103 mounted to an elongate drive shaft 105 and a plurality of support ribs 107 extending between walls 103. Each wall 103 has several rotationally spaced, half-circle shaped openings 109 around rim of wall 103 sufficient in size to permit sugar-juice to flow quickly from interior cavity 113 of member 81 to tank 71. Perforated member 81 also includes a hollow, perforate cylindrical drum 115 sized to be snugly attached to and supported by ribs 107 and walls 103.

As shown in FIGURE 4, drum 115 has a large number of holes 117 radially formed therein to provide flow paths permitting liquid to flow into and through perforated member 81 to tank 71 as such liquid is squeezed from pith 66. Such holes 117 are preferably of uniform diameter along their length.

Referring additionally to FIGURE 5, compression member 83 includes a pair of disk-shaped end plates 119 mounted to an elongate drive shaft 121. A generally cylindrical, imperforate support tube 123 has each of its ends mounted and attached to a plate 119. A generally cylindrical, resilient outer portion 125 is mounted on support tube 123 so that interior surface 127 of such portion 125 is in contact with and supported by tube 123 along substantially entire length of portion 125. In a highly preferred embodiment, portion 125 is made of natural or synthetic rubber having a hardness in range of 30-50 Durometer and a hardness of about 40 Durometer is preferred. The use of a resilient compression member 83 is highly advantageous, especially since pith-squeezing forces used in new apparatus 60 are relatively low. Because of its resilience, compression member 83 responds well to a mass of pith 66 of somewhat uneven thickness and compresses such pith with generally uniform force notwithstanding such thickness variations. In known machines using high compressive forces, thickness variations in mass of pith are simply overpowered by "brute force." And, if compressive force is reduced, some pith escapes compression or is only lightly compressed.

Perforated member 81 and compression member 83 are mounted in such a way that pressure at "nip" of extraction assembly 86, that is, that nominal line of contact between perforated member 81 and compression member 83, can be adjusted. In a highly preferred embodiment, compressive pressure between members 81, 83 is relatively light compared to that in a conventional mill roll. For example, density of pith 66 which has been compacted by vibration levelling is about 31 pounds per cubic foot. Juice starts to be extracted from such pith when it is compressed to a density of about 65 pounds per cubic foot. Using a three-extractor system, about 99% of juice is extracted when compressed density is increased to about 116 pounds per cubic foot. This latter density results when a compressive force of about 40 pounds per square inch is applied by members 81, 83 to pith 66. Referring now to FIGURES 1, 2 and 6, urging means 98 includes a rotatable pre-compression or feeder member 129 having a cylindrical, generally smooth outer shell 131 with radial projections 133 arranged thereon. Such projections are substantially smooth, half-cylinder- shaped elements 133a having rounded tops and ends and extending along length of member 129. Rounding of such elements 133a results in "self-scouring" operation in that pith tends to be freed from elements 133a as feeder member 129 rotates. Elements 133a are parallel to one another and to third axis of rotation 135 and are circumferentially spaced about shell 131 generally equidistant from one another. Further, third axis 135 is generally parallel to first and second axes 95, 97. Feeder member 129 ia preferably mounted so that the locus of its axis of rotation 135 can be adjusted (as indicated by arrow 136) to provide greater or lesser pre-compression of wetted pith fed into extraction apparatus 60. Pre-compression of such pith to about 40-50% of its volume has been found to be satisfactory although degree of pre-compression can vary widely. Feeder member 129 is driven at a linear speed substantially equal to that of perforated member 81 and compression member 83. Member 129 may be rubber-clad and resilient or made entirely of metal and rigid. After pith 66 is compressed to extract sugar-bearing juice therefrom, it flows to a receiving apron 137 and thence to a conveyor 64 where it is directed to next apparatus 60, to de-watering station 62 or to other processes, as case may be. As means for removing pith which adheres to perforated member 81 following compression, upper edge 139 of apron 137 is a "doctor blade." Such edge 139 rides on perforated member 81 and scrapes pith from it.

Even using a doctor blade, a small amount of pith may still adhere to perforated member 81. The lower portion of member 81 is in tank 71a and immersed in liquid. Adhering pith is rewetted to aid in its removal, either by simply being washed from perforated.member 81 into liquid or by being mechanically removed by a brush 141. Where pith adhesion is a problem, apparatus 60 also includes a generally cylindrical brush 141 mounted for rotation about a fourth axis 143 which is parallel to first axis 95. Such brush 141 is positioned generally above level of liquid in tank 71a to contact perforated member 81 at a post-immersion position. The bristles extend into and through holes 117, thereby removing pith. Brush 141 is preferably a non-powered or idler brush but it may be powered for rotation. As further pith-removing means (or in lieu of foregoing brush 141) , apparatus 60 may also include a pump (not shown) submerged in tank and a submerged spray bar connected thereto. Upwardly directed jets from spray bar impinge on member 81 and remove pith. Extraction apparatus 60 also includes means such as a weir 145 associated with tank 71a for separating solids from sugar-juice bearing liquid as both collect in tank 71a. As shown in FIGURE 2, weir 145 extends vertically upward from bottom.of tank 71a to a level somewhat less than that defined by tank upper lip 147. Pith solids which find their way into tank 71a tend to settle to bottom. The cleaner liquid nearer the top of tank 71a flows over weir 145 to a holding area 149. From there it is withdrawn by a pump 151 for circulation to the preceding extraction apparatus 60 or to other processing equipment (not shown) for extraction of sugar from juice. Extraction apparatus 60 also includes means such as a pump 151 and conduit 70 to recycle liquid from tank 71a to holding means 69. Pump 151 is connected between the bottom of tank 71a and conduit 70, draws liquid (with entrained solids) therefrom, and pumps it for delivery into holding means 69.

Referring further to FIGURE 1, de-watering station 62 is configured and arranged much like apparatus 60. Such station 62 includes a fresh water inlet 153 for introducing clean makeup water to substantially dry pith 66 from third extraction apparatus 60. The preferred quantity of water is about 20% by weight of incoming pith. Urging means 98, such as a rotatable feeder member 129, pre-compresses and urges pith into the nip of members 81 and 83 where it is compressed and de-watered. De-watered pith flows down a screen slide to a conveyor 84 which removes it for further processing.

Merely to give an idea of scale, the members 81 and 83 have diameters on order of 3 feet and are several feet in length. The resilient outer portion 125 of member 83 has a wall thickness of about 4 inches. Feeder member 129 has a diameter on order of 2 feet and is of the same length as members 81 and 83. However, one may depart widely from these nominal dimensions without departing from spirit of invention. In one preferred embodiment, the extractor system 61 shown in FIGURE 1 is capable of processing about 50,000 pounds of pith 66 per hour and extracts about 99% of sugar-bearing juice therefrom. While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of invention.

Claims

CLAIMS :

1. Apparatus for continuous-process extraction of juice from substantially rind-free juice-bearing pith of sugarcane, sorghum or the like comprising:

-means for holding a supply of substantially rind-free pith;

-a tank for receiving liquid; and

-an extraction assembly between holding means and the tank and having a rotatable perforated member and a. rotatable resilient compression member, the rotatable members positioned and arranged to squeeze therebetween pith from an input region adjacent thereto , whereby juice is pressed from the pith through the perforated member to fall into the tank.

2. The extraction apparatus of claim 1 wherein the compression member has a resilient outer portion adjacent to the perforated member and of a thickness and resiliency to receive and compress a mass of pith of uneven thickness, thereby to extract juice.

3. The extraction apparatus of claim 2 wherein the perforated member has an interior cavity and at least one lateral wall forming a plurality of rotationally-spaced openings sufficient in size to permit juice to flow quickly from the interior cavity to such tank.

4. The extraction apparatus of claim 1 further including means adjacent to the input region for urging the pith in the input region toward the extraction assembly.

5. The extraction apparatus of claim 4 wherein the urging means is a rotatable feeder member pre-compressing the pith and having radial projections arranged thereon to move the pith along the input region toward the extraction assembly to urge the pith into the extraction assembly.

6. The extraction apparatus of claim 5 wherein the feeder member is generally cylindrical and the projections are spaced thereon and have circumferentially spaced ridge-like elements.

7. The extraction apparatus of claim 1 wherein the perforated member has a lower portion situated in the tank, whereby pith still adhering to the perforated member is immersed in liquid to rewet it and thereby aid in removing it from the perforated member.

8. The extraction apparatus of claim 7 further including means contacting the perforated member in a position after immersion thereof to remove rewetted pith from the perforated member.

9. In a method of making products from constituents of the juice-bearing pith of sugarcane, sorghum or the like including the steps of separating juice-bearing pith from rind, extracting juice from such juice-bearing pith, and subsequent processing steps on one of said constituents as appropriate, the improvement wherein the extraction step comprises squeezing juice-bearing, rind-free pith between a rotating perforated member and a rotating resilient compression member.

10. The method of claim 9 wherein the rotating members define a nip at the end of a pith input region and the method further includes repetitively urging pith in the input region toward the nip, whereby pith is continuously received between the rotating members for extraction of juice.