AU2007344369B2

AU2007344369B2 - Mill for extracting sugar cane juice from a product sheet

Info

Publication number: AU2007344369B2
Application number: AU2007344369A
Authority: AU
Inventors: Michael Fiebig; Philippe Herlant; Jean Urbaniack
Original assignee: Fives Cail Babcock SA
Current assignee: FIVES CAIL
Priority date: 2006-12-14
Filing date: 2007-12-11
Publication date: 2012-06-21
Anticipated expiration: 2027-12-11
Also published as: WO2008087280A2; CN101589158B; ZA200903905B; AU2007344369A1; CN101589158A; BRPI0720081B1; FR2910026B1; FR2910026A1; BRPI0720081A2; WO2008087280A3

Abstract

The invention relates to a mill for extracting sugar cane juice from a sheet of products, said mill including at least two pressing cylinders (2) rotating in opposite directions for driving and pressing the product sheet at a compression area (3) and discharging the juice, and a downstream outlet area (4) of said product sheet, wherein one at least of the two cylinders (2) may include peripheral annular grooves (5) for the flow of extracted juice, the mill further comprising means (7) for limiting the re-absorption of the sugar cane juice after pressing. The means for limiting the re-absorption of the sugar cane juice include, in the downstream outlet area (4) of the product sheet, an anti-expansion channel (8) located downstream from the pressing area (3) and in which the pressed product sheet is fed under the action of the rotating cylinders, and means for adjusting the channel section for compacting said sheet at least locally in the channel. According to the invention, the channel (8) includes at least one section of a given length along which the channel is divergent, also called expansion area, followed by said means (9) for adjusting the section of the channel (8) for making the channel convergent along a section of a corresponding length, also called the counter-pressure area.

Description

1 MILL FOR EXTRACTING SUGAR CANE JUICE FROM A PRODUCT SHEET Technical Field [00011 The invention relates to a mill for extracting sugar cane juice from a product sheet. Background of the Invention [00021 Today, for extracting the juice from sugar canes, first of all, a prior stage is implemented, during which the sugar cane is prepared using materials, such as knives, processors, or shredding devices known as "shredders". [00031 For instance, a shredder is formed of a mobile rotor including a set of 100 to 200 hammers of 20 to 30 kilos revolving at speeds as high as 900 to 1100 rev/min, enabling to open the cane cells including the sugary juice so that the mills may extract the juice. [00041 The products thus prepared supply a pressing system composed generally of a set of 4 to 7 mills in series. Each mill extracts a portion of the juice. This enables the set to extract up to 98% approximately of the sugar contained in the cane. 10005] The mills known include generally at least three pressing cylinders revolving in opposite directions, in particular consisting of cylinders with rafters. The latter also include grooves for better discharge of the juice. Between these pressure areas, it is known to guide the pressed cane by using a trash blade which maintains the cane compacted so as to extract at best the juice from the cane. [0006] However, at said trash blade, a loss in energy by friction of the cane may be noticed. Upon completion of the ultimate pressing of each mill a re-absorption of the juice on the cane may be observed, which undergoes rapid de-compaction. This is detrimental regarding the pressing throughput and requires the use of several pressing cylinders successively. 100071 Document FR-2.706.808 or still document FR-2709.700 divulge a device for improving the efficiency of the cylinder presses for extracting liquids, and in particular cane sugar. This device includes a channel downstream of the pressing cylinders, called A2lY7S1 -rPR 2 chute, and a barrier creating a bottleneck in the chute. The mills fitted with such a device enable to extract up to 70% of the juice during the first pressing. 10008] There is a need to provide a mill for extracting the cane juice exhibiting in particular a perfected device limiting the re-absorption of the cane juice after pressing, whose performances are greater than with known systems. 100091 There is also a need to provide a mill of greater throughput, enabling to extract at least 75% of the juice during the first pressing. [00101 There is also a need to provide a mill whereof the energy consumption is smaller than the mill of the previous art. [00111 There is a further need to provide a mill composed solely of two pressing cylinders. Object of the Invention [00121 It is an object of the present invention to substantially achieve one or more of the above needs, or to at least provide a useful alternative. Summary of the Invention [00131 There is provided herein a mill for extracting sugar cane juice from a product sheet, said mill including at least two pressing cylinders revolving in opposite directions for driving and pressing the product sheet at an area intended for compressing and discharging the juice and a downstream outlet area of the product sheet, wherein at least one of the cylinders comprises peripheral annular grooves, provided for letting the extracted juice flow, the mill further comprising means for limiting the re-absorption of the cane juice after pressing, exhibiting, in the downstream outlet area of said product sheet, on the one hand, an anti-expansion channel, situated downstream of the pressing area, and inside which the pressed product sheet is directed, under the action of the cylinders rotatably, and on the other hand, means for adjusting the section of the channel, for compacting said product sheet in the channel, at least locally, wherein said anti-expansion channel exhibits at least one length whereon the channel is divergent, also called expansion 3 area, followed by said means for adjusting the section of the channel for making the channel convergent over a section of a corresponding length, also called counter-pressure area. Brief Description of the Drawings [00141 Preferred embodiments of the invention will be described hereinafter, by way of examples only, with reference to the accompanying drawings, wherein: [0015] Figure 1 is a side view of a mill complying with the invention according to an embodiment; [00161 Figure 2 and Figure 3 are partial views of the mechanism for pressing and limiting the re-absorption as illustrated on Figure 1, in two positions of the means for adjusting the section of the channel; [0017] Figure 4 is a partial sectional view of an embodiment of the pressing cylinders, which include triangular rafters and annular grooves for discharging the juice; 100181 Figure 5 and Figure 6 are respectively front and side views of a comb element enabling to clean the rafters illustrated on Figure 4; 100191 Figure 7 is a partial principle sketch of a mill complying with the invention according to a second embodiment; 100201 Figure 8 is a partial principle sketch of a mill complying with the invention according to a third embodiment; [0021] Figure 9 is a partial principle sketch of a mill complying with the invention according to a fourth embodiment; and 10022] Figure 10 is a graph illustrating for instance the evolution of the pressures of the products at the three successive areas of the channel of the mill, as illustrated on Figures 7 4 to 9, i.e.: the first length whereon the channel is convergent (area 20), said expansion area (area 30) and the counter-pressure area (area 40). Detailed Description [00231 The invention relates to a mill for extracting sugar cane juice from a product sheet. 100241 The mill 1 includes at least two pressing cylinders 2 revolving in opposite directions for driving and pressing the product sheet at an area 3 intended for compressing and discharging the juice, and a downstream outlet area 4 of said product sheet. [00251 Still, the invention will find an application in mills fitted with two pressing cylinders only, without however being limited thereto. It is also possible, for instance, to consider said invention with conventional mills fitted with three to six cylinders. 100261 The mill exhibits moreover means for limiting the re-absorption of the cane juice after pressing. [0027] In this view, at least one of both cylinders 2 may exhibit peripheral annular grooves 5 provided for the flow of the extracted juice. As illustrated on Figure 1, according to an instance, both pressing cylinders 2 mesh into one another, in particular at rafters 52. The grooves 51 are then stowed by the rafters 51. Moreover, the mill may exhibit at least one comb element 6 for cleaning the rafters 52 as well as a device for cleaning the grooves 51. This comb element 6 enables to remove the products compressed in the rafters. As illustrated on Figure 5, according to an example, these rafters have a triangular profile. 100281 The means 7 for limiting the re-absorption of the juice exhibit, moreover, in the downstream outlet area 4 of the product sheet, on the one hand, an anti-expansion channel 8, situated downstream of the pressing area 3, and inside which the compressed product sheet is directed, in particular pushed and under the action of the rotating cylinders, and on the other hand, means 9 for adjusting the section of the channel 8, for compacting said sheet in the channel, at least locally.

5 [0029] By anti-expansion channel is meant a chute enabling to channel the products, preventing said products from becoming loosened completely and left around without any constraint. [0030] According to an embodiment, the anti-expansion channel 8 exhibits at least one length whereon the channel is divergent, also called expansion area, followed by said means 9 for adjusting the section of the channel 8 for making the channel convergent over a corresponding area, so-called counter-pressure area. [00311 According to an embodiment, said means of adjustment 9 consist of at least one pivoting cam 10 whereof the guiding wall of the products is tiltable. 100321 It was observed that it was possible to dry the product sheet again, after a first pressing operation, by releasing the pressure in a controlled fashion and by exerting a new pressure in the sheet, in particular of the same intensity. [00331 Also, according to an embodiment, the divergent expansion area enables partial release of the products before further compression in the counter-pressure area. The mill as illustrated according to the example of Figures 1 to 4, enables thus to subject the products successively to a first compression between the cylinders 2, at the pressing area 3, releasing the products thanks to the first length whereon the channel is divergent, then to another compression of the products into the counter-pressure area. [00341 It is thus possible to extract more juice than with state-of-the-art mills, or still possible to extract the same amount ofjuice but while consuming less energy for actuating the cylinders. An improvement in the extraction of the juice of 5% or more could be observed. [00351 As illustrated according to the example of Figures 1 to 4, the anti-expansion channel 8 may be divergent, at least over a first length. In particular, the lower and upper walls of the channel 8 may form an angle "a" relative to the average direction 13 of the channel, ranging between 2 and 100, at least over said first diverging length.

6 100361 According to an embodiment illustrated on Figures 2 or 3, the angle "a" may in particular be equal to 5. [00371 As illustrated according to an embodiment, the means 9 for adjusting the section of the channel 8 consist of a pivoting cam 10, whereof the tilting enables to adjust the section of the channel locally and transversally. 100381 The cam 10 may in particular exhibit a guiding wall 15 of products. This guiding wall 15, arranged over the whole width of the path of the compressed cylinder, forms, at least partially, an internal wall of the channel, at least over a second length. 100391 The cam angle, marked P on Figure 3, i.e. the angle of the guiding wall 15 relative to the average direction 13 of the channel 8, may be determined for making the channel convergent, at least over a second length. 100401 In particular according to an embodiment illustrated on Figure 3, the lower and upper walls of the channel form a 5*-angle "a" relative to the average direction 13 of the channel, over a first portion of diverging length. The cam angle, i.e. the angle "p", formed between the guiding wall 15 of the products and the average direction 13 of the channel 8 may be of the order of 150 over a second length. 10041] The cam angle can be adjusted manually by an operator, or still automatically. Thus, the mill may exhibit moreover a load sensor or a torque sensor targeting the loads induced by the sheet compacted in the channel on said cam 10. 100421 The mill may then exhibit means for slaved tilting of the cam, throughout the pressing method, in relation to the measuring signals of the sensor and to a given set value, in particular a load value or still a torque value. [00431 The mill may exhibit moreover means 11 for adjusting the tilting of the cam, in particular formed of a hydraulic or still electrical jack 12.

7 [00441 As illustrated, the average direction 13 of the anti-expansion channel may be oblique, descending. For instance, the average direction 13 may form an angle relative to the horizontal ranging between 10 and 300 in particular equal to 200. 100451 In a preferred embodiment, the mill includes two pressing cylinders 2 and said two pressing cylinders 2 may be provided with peripheral annular grooves 51 and rafters 52, the mill exhibiting for each cylinder a comb element 6. [00461 As illustrated on Figure 1, the mill may then exhibit three cylinders forming a triangle, in particular guided by bearings 16. Two of the cylinders are the pressing cylinders 2, the third one being a cylinder 14 provided for conveying and guiding the product sheet. [00471 As illustrated on Figures 2 and 3, the lower and upper walls of the channel may be formed at least partially of two blocks 18, 19, closed laterally by flanges. [00481 The lower block 18 may be parallelepipedal in section and exhibit a supporting surface with bores in particular for adjusting and fastening the comb elements 6, in particular by screwing. 10049] The upper block 19 may be smaller than the lower block 18. It may exhibit a rear wall sized for co-operating rotatably with the pivoting cam 10. The rear wall may exhibit in particular a curving radius substantially similar to the curving radius of a semi-circular generatrix of the pivoting cam 10. [0050] As illustrated, the upper block may exhibit on a front wall, a surface for fastening a comb element 6, in particular provided with bores for a screw-fastening. [00511 According to an embodiment illustrated according to the variations of Figures 7 to 9, the anti-expansion channel 8 may exhibit three successive lengths, i.e.: - a first length whereon the channel 8 is convergent, area marked 20, - a second length whereon the channel is divergent, said expansion area 30, 8 - a third length of the channel whereon the channel 8 is convergent, corresponding to said counter-pressure area 40 . [00521 The graph of Figure 10 illustrates the internal pressure of the products (in bars) on the axis of the ordinates in relation to the position of the products over the length of the channel. Three curves are plotted, each corresponding to a particular tilting of the pivoting cam 10 on the mill and to the geometries of Figures 7 to 9. 10053] It can thus be observed, as the products progress and are fed in the channel 8 that the internal pressure increases in the area marked 20, decreases into the expansion area 30 and increases again and significantly in the counter-pressure area 40. [00541 The products are thus subjected to three compressions, i.e.: a first compression between the pressing cylinders 2, followed by an expansion of the products into the downstream outlet area 4 of the sheet, a second compression into the convergent area marked 20 of the channel 8, followed by a second expansion in the expansion area marked 30 of the channel 8, and finally a third compression into the counter-pressure area 40 under the action of the means for adjusting the section of the channel, and in particular of the pivoting cam 10. Optimal extraction of the juice from the product sheet is thereby ensured. [00551 The juice flows at the input 25 to the channel upstream of the area 20 and at the output 35 of the expansion area 30, upstream of the counter-pressure area 40, as simulated by the arrows on Figures 7 to 9. 10056] Said outlet 35 is in the form of an orifice consisting of an opening created between the end of the channel 30 and the beginning of the means for adjusting the section of the channel. [0057] For easier discharge of the juice, the channel may be provided with orifices 21 for discharging the extracted juice, wherein such orifices may be, as illustrated on Figures 7 to 9, distributed particularly on the expansion area 30 of the channel.

9 [00581 As illustrated in the examples of Figures 7 to 9, the mill may exhibit two pivoting cams 10, capable of "pinching" the product sheet on the counter-pressure area 40. 100591 It should be noted that the patterns of the examples of Figures 7 to 9 are not limitative. Also and although not illustrated, the mills of Figures 7 to 9 may be provided with comb elements for cleaning the rafters of the pressing cylinders 2 and with a device for cleaning the annular grooves. [00601 Naturally, other embodiments, understandable to the man of the art, could have been contemplated without departing from the framework of the invention defined by the disclosure herein.

Claims

1. A mill for extracting sugar cane juice from a product sheet, said mill including at least two pressing cylinders revolving in opposite directions for driving and pressing the product sheet at an area intended for compressing and discharging the juice and a downstream outlet area of the product sheet, wherein at least one of the cylinders comprises peripheral annular grooves, provided for letting the extracted juice flow, the mill further comprising means for limiting the re-absorption of the cane juice after pressing, exhibiting, in the downstream outlet area of said product sheet, on the one hand, an anti expansion channel, situated downstream of the pressing area, and inside which the pressed product sheet is directed, under the action of the cylinders rotatably, and on the other hand, means for adjusting the section of the channel, for compacting said product sheet in the channel, at least locally, wherein said anti-expansion channel exhibits at least one length whereon the channel is divergent, also called expansion area, followed by said means for adjusting the section of the channel for making the channel convergent over a section of a corresponding length, also called counter-pressure area.

2. A mill according to claim 1, wherein the anti-expansion channel exhibits three sections of successive lengths, wherein the lengths comprises: - a first length whereon the channel is convergent, - a second length whereon the channel is divergent, also called expansion area, - a third length whereon the channel is convergent, corresponding to said counter pressure area.

3. A mill according to claims I or 2, wherein the channel is provided with orifices for discharging the juice.

4. A mill according to claim 1, wherein said means of adjustment consists of at least one pivoting cam having a guided wall that is titable.

5. A mill according to claim 4, wherein said counter-pressure area is provided with two pivoting cams. 11

6. A mill according to any one of claims I to 5, further comprising a load sensor or a torque sensor targeting the loads induced by the sheet compacted in the channel on said cam, the mill further comprising means for slaving the tilting of the cam in relation to the measuring signals of the sensor and to a given set value.

7. A mill according to any one of claims 1 to 6, further comprising means for adjusting the tilting of the cam formed of a jack.

8. A mill according to any one of claims 1 to 7, wherein the average direction of the anti-expansion channel is oblique, descending.

9. A mill according to any one of claims 1 to 8, wherein each of the pressing cylinders are provided with peripheral annular grooves, the mill comprising for each cylinder a comb element.

10. A mill according to any one of claims 1 to 9, comprising three cylinders forming a triangle, two of the cylinders being the pressing cylinders, the third one being a cylinder provided for conveying and guiding the product sheet.

11. A mill for extracting sugar cane juice from a product sheet, said mill substantially as hereinbefore described with reference to the accompanying drawings. Dated 27 April 2012 Fives Cail Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON

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