Patent Publication Number: US-2021169008-A1

Title: Pre-processing of sugar cane

Description:
TECHNICAL FIELD 
     THIS INVENTION relates to pre-processing of sugar cane and in particular but not limited to improvements in harvesting, trash separation and washing as a process prior to milling. 
     BACKGROUND 
     Sugar can is the world&#39;s largest crop and is grown mostly in tropical regions with high rainfall. Brazil is by far the highest cane producer. It is believed that cultivation first started in India in 327BC but may have been as early as 8000 BC. Sugar cane was harvested by hand until the first Massey Ferguson chopper harvester was produced in 1958 at Ingham in Queensland, Australia. The cane was fired in the usual way before harvesting. Over the following years local farmers assisted development notably with the addition of power feeders, blowers and extractors. The effect of these additions may be seen as a cloud of trash being thrown into the air and floating on the prevailing wind. This waste is rendered amorphous and it is not readily apparent whether actual juice bearing cane is being trashed. Hand harvesting is still used in some countries. It would be desirable to provide an economical and efficient mechanical alternative in these countries. 
     Under this scheme of disposing of trash infield, which remains in the norm in mechanised harvesting to this date, the cane is pre-processed and billeted by the harvester and is delivered to the mill substantially ready for milling. Logic would have it that this is very efficient. It is counter intuitive to think that there are any real problems associated with this idea. 
     However, Applicant has recognised that this may not be so. What if the so called “trash” is not all trash. Since the so called trash exits the harvester as an amorphous “cloud” how can one be certain that over time commercial quantities of valuable cane is not being inadvertently processed as “trash”. 
     Applicant has considered the operation of existing harvesters and in hindsight the amount of wasted cane should depend on the harvester speed. The faster the blowers and extractors are driven the more cane is likely to be lost. 
     Applicant has also realised that it is also counter intuitive to conclude that the obvious solution is a reduction in speed and this will ultimately benefit collection efficiency since lower speed means less trash is ejected. Applicant observes that there are downstream consequences of more trash as it means more trash and dirt to the factory increasing trash and dirt loading and wear at the mill as well as greater requirements for vacuum separation and clarification due to excess mud. The balance can be hard to achieve as the actual infield environs are also variable. 
     In order to improve the overall effect is in Applicant&#39;s counter intuitive proposal to collect all cane infield and then centralise the trash removal in a more controlled way prior to further process. The recognition of this idea is Applicant&#39;s main invention. Accompanied with this invention is a practical application of it with implications arising from it in terms of equipment design and function, notably in new harvester design, trash separation/removal and cane washing. These represent further inventions in their own right individually and in combination. Even though the harvester, trash separator and cane washer herein are independent, in implementing Applicant&#39;s process cane is treated by them so the treatment of the cane before and after creates a working interrelationship between them in terms of the process. 
     The harvester, trash separator and cane washer herein arise unexpectedly from first having in hand the revolutionary concept of infield whole cane mechanical harvesting. This is contrary to a long standing industry trend for trash removal infield. 
     A relatively recent patent for a conventional harvester is described in U.S. Pat. No. 8,240,115 dated 2012. There are a very large number of patents dealing with infield cane harvesters. A non-exhaustive and fairly random list spread over time shows the dominance of infield trash separation and would include from 1972 U.S. Pat. No. 3,673,774; from 1978 U.S. Pat. No. 4,098,060; from 1982 U.S. Pat. No. 4,343,140; from 1985 U.S. Pat. No. 4,555,896; from 1992 U.S. Pat. Nos. 5,092,110 and 6,363,700. They are all along this basic theme of trash removal infield. They tend to be all very complex due to having to remove the leafy material from the cane stalks. 
     These and the others should be referred to in order to demonstrate that in all the circumstances the notional skilled person would be presented with many similar solutions in an old, mature and crowded art yet Applicant&#39;s invention escaped the skilled person over these many years. Since the present invention arises in a crowded art it would be prima facie wrong to suggest that there was, or is, a particular problem or motivation extant at the filing date of the present application that would give rise to the non-inventive notional person coming up with the present invention either in idea, concept or practical form. Thus the recognition and the present conception may be considered as whole or part of Applicant&#39;s inventive step. 
     With this and the other background factors, including as set out above, in mind, it should be clearly appreciated to the reader, that it is elementary that exercise of the inventive faculty in all the circumstances, in such a crowded art, is likely to be present in small variations. This is a background observation in hindsight only and is not to say that any of Applicant&#39;s new features whether individually or in combination are in any way slight or small. 
     Even though the art has become crowded, according to Applicant&#39;s understanding of the marketplace if there have been many offerings, they have not been widely accepted in the field of cane harvesting. 
     Consequently, there is a requirement for a fresh look “outside the box” through new eyes in an effort to provide an alternative to the efforts made over the last many years. It would be desirable to have something that is simple and easy to assemble, yet effective, but employing common techniques and methods to arrive at a new and useful combination and result. Simplicity, is not considered a bar to invention but in a crowded art may indeed be an indicator of invention. 
     This means that the present invention does not arise through any deterministic relationship to the prior art but rather is the inventor&#39;s own inspiration in an individualistic way applying the inventor&#39;s mind to the general state of the art and to the inventor&#39;s knowledge and recognition of defects arising including during his prototyping and development that might be remedied, this being as an alternative to what is currently available, rather than an effort to deal with any specific generally recognised real extant problem common at the time or any notional problem derived ex post facto from any single item of prior art, selected by hindsight, from a clearly crowded art, since any selection in a crowded art must necessarily be based on Applicant&#39;s disclosure as the starting point. Selection of features from what are otherwise workable solutions to match Applicant&#39;s claims must necessarily involve rejection of other features from the combinations disclosed in those solutions. 
     Outline 
     In one aspect there is provided a method for preparing sugar cane comprising the steps of:
         1. mechanically cutting and collecting a batch of substantially whole cane infield;   2. delivering the batch of cane to a trash separator and subsequently separating trash from cane in the batch; and   3. delivering the trash separated cane for further processing.
 
Preferably, the process further involves the step of washing the trash separated cane.
       

     In another aspect there is provided a system for pre-mill cane processing by infield whole cane harvesting using a whole cane harvester to prepare a batch of substantially whole cane; a trash separator for separation of trash to produce trash separated cane for further processing. Preferably, the system further employs a trash separated cane washer used to wash cane prior to milling. 
     As mentioned above one consequence of infield whole cane harvesting means a non-conventional harvester in so far as trash is not processed on the harvester. Thinking outside the prevailing norms means that the harvester does not need a trash extractor or a blower, again it is counterintuitive but a consequence of no blower is a saving of infield fuel consumption. The present harvester does not require many of the features of a conventional harvester including conveyors and blowers. 
     Apart from the above omissions Applicant has made additional improvements in harvesters which may be employed individually or in combination. Each improvement is set out below independently and in combination it being appreciated that Applicant may divide the present improvements into separate patents. 
     In one improvement, in a cane harvester, there is provided an integrated modular feed system for removal and repair or for changing operative row width. In an example and a variation the harvester may be configured for cutting two rows, each row having a row feeder sharing a common billet cutter. Typically, the flow paths are tapering inwardly to the bill cutter. 
     In a second improvement, in a cane harvester, there is provided inclined cane base cutters with a forward downward angle of attack to cut close to the ground. 
     In a third improvement, in a cane harvester, there is provided a cane billet thrower to deliver cane billets and trash to an adjacent infield transporter. 
     In a fourth improvement, in a cane harvester, there is provided a floating front feed system for undulating terrain. Preferably, the feed system is made floating by a counter weight or force for the feed system. Typically, this may be any device to provide upward lift including chains, cables, springs hydraulic drives or the like. In the case of two row feeders, each row is preferably controlled independently. In one preferred form an adjustable length bias spring is employed and the feed system is pivotally mounted to the harvester. 
     In a fifth improvement, in a cane harvester, having a front end of a carriage there is provided a feed system extending from the front end, the feed system being adapted for elevation independently of the front end. The feed system typically employs a forward section upstream of base cutter blades, the forward section being floating relative to the angle of attack of the cutter blades. In a preferred form of this embodiment the forward section is made floating by reason of sets of spaced linkages guiding the front section between limits. The limits are typically provided by mating curved sections. The linkages connect to the curved sections which abut at upper and lower range of relative movement between the forward section and the cane base cutter blades. The blades are typically set at an inclined angle of attack with each blade formation generally following the edge of an inverted shallow dome configuration or equivalent. 
     In a sixth improvement, in a cane harvester, the harvester has a carriage comprising a prime mover and a chassis, and a transportation footprint, the footprint being within the boundaries of a shipping container, preferably a 20 ft shipping container. 
     In a seventh improvement, in a cane harvester, there is provided interdigitated spaced billet cutters having radially extending circumferentially spaced blades so dimensioned and arranged for lifting and passing stones of up to about 200 mm. 
     In an eighth improvement, in a cane harvester, there is provided billet chopper replacement blades adapted to slide out sideways for each for replacement. 
     In a ninth improvement, in a cane harvester, there is provided a shortened billeting and feed assembly comprising inclined feed conveyors, base chopper blades, a rotary conveyor, billet cutters leading onto a billet thrower. 
     In a still further improvement, in a cane harvester, there is provided a modular set up in a cane harvester as described herein where the harvester may be reconfigured as a boom sprayer. 
     In another aspect another is provided a trash separator or trash remover having an input conveyor for billets and trash which delivers the billets and trash through an entrance onto a curved grate through which air is driven to remove trash. The conveyor is preferably inclined to the axial line of the grate. 
     In a further aspect there is provided a cane washer having a washer tank having a billet inlet and billet outlet, an agitator/conveyor within the tank, a billet elevator communicating with the outlet, a liquid entry to the tank from downstream process and a return liquid collector below the elevator to return liquid to downstream process. 
     In a further aspect there is provided in a preferred embodiment, in a process as described above, a harvester as described, feeding a trash remover as described, in turn feeding a washer described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the present invention, aspects and improvements may be more readily understood and put into practical effect reference will now be made to the accompanying drawings which illustrate preferred embodiments and wherein: 
         FIG. 1  is an overall schematic block diagram illustrating general application of the present invention in a preferred form; 
         FIG. 2  is a drawing illustrating modular aspects of a typical harvester; 
         FIG. 3  is a drawing illustrating modular aspect of a two row harvester with independent modular feeders; 
         FIGS. 4 and 5  are end and side views of the harvester of  FIG. 3 ; 
         FIGS. 6A through 6B  are drawings illustrating the adjustable spring bias and raising features of the prime mover attached to the modular row feeder; 
         FIGS. 7A and 7B  illustrate further details of that arrangement; 
         FIGS. 8A through 8C  are drawings illustrating how cane is cut and billeted in the harvester according to the present invention; 
         FIG. 9  is a drawing of a billet cutter capable of passing quite large stones; 
         FIG. 10  is an exploded view of a trash separator/remover; 
         FIGS. 11A through 11D  are further drawings of a trash remover according to the preferred form; 
         FIGS. 12A through 12D  illustrate operation of part of the trash remover of the preceding figures; 
         FIGS. 13A through 13C  are views illustrating a billet conveyor that feeds billets by gravity through the trash remover of the preceding figures; 
         FIG. 14  is an exploded view illustrating a washer unit according to the present invention; 
         FIGS. 15A through 15D  illustrate different views of the billet washer of the preceding figures; 
         FIGS. 16A through 16B  are drawings of an end view of a typical billet washer and a section through A-A of  FIG. 16A ; 
         FIGS. 17A through 17D  are drawings illustrating a preferred relationship between the front of the feed and billeting unit and its cutter blades; and 
         FIGS. 18A and 18B  are top and side schematics of a variation employing a single module for two rows. 
     
    
    
     METHOD OF PERFORMANCE 
     Referring to the drawings and initially to  FIG. 1  there is illustrated an overall system  10  for infield collection of whole cane and delivering that cane to a mill via a trash separator and a washer. In the embodiment illustrated a harvester  11  collects whole cane and throws billeted cane into an infield transporter  12  which then transports this to a centralised trash separator  13 . Now it will be appreciated that this trash separator may service any number of infield transporters and may be located at the mill or at another centralised location so that output from the trash separator may pass on to a conveyor  14 . Billets  15  are then fed to a washer  16  which in this embodiment is configured so that the washer is upstream of a mill. This means washing liquid from downstream process from say mill  2  in milling tandem may be used in the washer. This liquid enters the washer at  17 . Mud and dirt is removed from the billets in return liquid at  18  which then passes to a mud removal unit  19  of conventional form. This juice is returned to the downstream process along line  20 . It will be appreciated that since whole cane is being transported to a dedicated trash separator at  13  that there is very little loss in terms of juice carrying cane. The billets are moved on to the mill at  21 . They will move to the first stage mill usually via a conveyor. Wash liquid may also be collected via an outlet conveyor from the washer. 
     Referring now to  FIG. 2  there is illustrated one example of a modular harvester  11  comprising a drive unit  22 , a removable billet thrower and chute  23  and  24  and a feed and billeter module  25  in this case being a two row unit which may be inserted under the chassis  26  and secured by pivot couplings  27  and  28  to corresponding mounts  29  and  30 . 
       FIG. 3  illustrates single row modules  31  and  32  and like numerals illustrate like features it being appreciated that in this embodiment the single row feed and billeting units  31  and  32  may pivot independently of each other. This is illustrated in  FIG. 4  where the module  31  is shown slightly higher in position relative to the module  32 . The thrower  23  is shown in its operative position with the chute  24  delivering billets to the left hand side of the harvester. 
     The assemblies  25 ,  31  and  32  are arranged to float and follow the ground surface over which the harvester moves and to this end each of the assemblies is biased into floating contact with the ground by reason of one or more spring assemblies  33  which are more clearly illustrated in  FIG. 6B . A wire rope  34  connects to an end plate  35  via a threaded adjuster  36 . An adjustment nut  37  is used to regulate, the length of the spring  38 . It will be appreciated that there is some adjustment of the spring in order to regulate the floatability of the feeders. By reason of the spring there will be a damping and shock absorption action that will retain the entry of the feeding to the harvester at the front due to the connection of the wire rope  34  relative to the pivot connections at  29  and  30 . 
     Quite independently of the spring assembly  33  are hydraulic ram assemblies  39 ,  40 ,  41  and  42  (part of which is shown) and these are used to elevate the feed units well away from the ground for transportation, servicing or for changing front wheels etc. 
     Referring now to  FIGS. 8A through 8C  operation of the harvester will be illustrated relative to cane shown at  42 . As can be seen in  8 B and  8 C hydraulically driven feed augers shown generally at  43  lead cane along the section aligned with B-B as depicted in  FIG. 8C . A blade  44  will cut any overlapping leaves between the two rows and then a paddle wheel  45  will force the cane to an angle of about 90° relative to inclined cutter blades  46 . This and the angle of attack of the blades which will cut off the cane very close to the ground therefore maximising the length of cane above the ground to be retrieved. The cut end is fed into the billet cutter feeder assembly at  47  thus effectively inverting the cane stalk as it is fed into the billet cutters  48 . The billets cut billets fall into the thrower  23  where they are ejected via the chute  24  into an infield transporter (not shown). 
     It will be appreciated that since there are no extractors or blowers the the trash is also fed along with the billets through the chute  24  into an infield cane transporter. The harvester can be made much shorter than conventional as there is a shorter travel of the cane through the harvester into the thrower. This permits containerisation of the harvester. 
     Since the cutter blades at  46  are inclined and are directed ostensibly at the very bottom of the cane stalks to cut them off, then there is a possibility that rocks and other debris might enter into the billet conveyor section, Consequently, the conveyor section also has rubberised fingers in, the paddle wheel at  49 . The cutter blades at  48  as illustrated in  FIG. 9  have their axles spaced so that the barrels  50  carrying the cutter blades  52  and the blades are so dimensioned and arranged that they may pass rocks up to, in this example, 211 mm with one such rock being illustrated by the circle at  53 . 
     As shown in  FIG. 1  once the cane has been harvested by the harvester  11 , located in the infield transporter it is then sent to a trash separator or trash remover  13  and an example of a trash remover  13  is shown in exploded format in  FIG. 10  with further details and operation being shown  FIGS. 11A through 130 . The components of the separator include intermediate ducting  54  which has a gravitational input and an output at  55  for billets. These fail on to a conveyor  14 . 
     In this case there is an input conveyor for billets and trash at  56  which delivers the billets and trash through an entrance to the ducting  54  at  57 . Inside the ducting is a curved separator grate  58  which exposes the lighter trash to a regulated aft flow. The grate is carded by grate support plates  59 ,  60  and  61 . Blower fans at  63  draw air through inlet at  64 . This arrangement of fans driven at an appropriate flow rate will provide removal of trash as billets progressively fall down and along the grate, travel around the curvature of the grate by gravity. The trash is blown off for collection in the cyclone at  65  and subsequent shredding. 
     The relative position of the conveyor  56  is shown in plan view in  FIG. 11A  and as can be seen it is inclined to the axial line of the ducting  54  and also inclined to the direction of the grate  58  with the relative arrangement of these shown in  FIG. 130 . The underside of the conveyor as shown in  FIG. 13A  showing the gravitational exit opening at  67  for the billets being carried by the conveyor. This exit opening locates and traverses the curved grate  58  as clearly depicted in  FIG. 130 . This opening relative to the billet conveyor effectively widens over the grate and allows for even flow of the billets across the full width of the grate  58 . This even flow means that there is an even distribution of clearing aft flow to blow trash away from the cane billets. This air flow is typically around 11 metres per second. This is illustrated with the trash particles shown at  66  in  FIGS. 12A through 12D . 
     As further is shown in  FIG. 1  as the trash removed billets leave the trash separator they move on to a conveyor  14 . They are conveyed to a washer  16  details of which are shown in exploded view in  FIG. 14  and through  FIG. 16B . A washer tank  68  holds a mixer, agitator  69 , with helical mounted blades  70  so that cane falls into one end of the tank  68  where it is propelled and agitated toward the other end. Here the billets are pulled onto an elevator assembly  71  with the bottom of the elevator travelling through the end at  72 . 
     Relatively dean low brix juice from the number 2 mill in a milling tandem is heated to about 100° C. and is used in the washer entering at  73 . The agitator speed is about 6 m/s to break up clods of dirt in cane roots. Relatively dirty return juice flows through a perforated plate  74  in the elevator assembly in collector tray  75  and also through drain  77  where it is returned back to process. 
     Referring now to  FIGS. 17A through 17D  there is illustrated another preferred embodiment of a front end section  78  of a feed and billeting module, similar to the module  25 . In this case the module has its cane lead-in conveyors  79  mounted to float by reason of sets of spaced linkages  80  and  81  (one set being shown in the drawings). 
     The linkages are shown connected to mating curved sections  82  and  83  which abut at upper and lower range of relative movement between the front and the cane base cutter blades  85  ( FIGS. 17C and 17D ). A typical range is illustrated in the drawings in mm at 30 mm (mid range), 88 mm (lower range) and 95 mm (upper range). 
     Thus the front  85  may cater for different row variations including furrows or hilled rows. 
     The blade sets  85  in this embodiment are forwardly inclined but as may be discerned from the side views of  17 A,  17 C and  17 D the blade formation generally follows the edge of an inverted shallow dome configuration or equivalent. 
     Whilst the above has been given by way of illustrative example many variations and modifications will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as set out in the appended claims. For example,  FIGS. 18A and 18B  illustrate a simplified schematic of a variation where rather than each row having its own module this is a two row module and chassis assembly  86 , in this case for a 1.8 m row spacing, the cutters  85  are used, and the basic feed is the same but the rows are fed into a common billet cutter  48  that they share. The chassis has a single front wheel  87  to aid turning. The cane flow path is indicated by the lines  88  and  89  which then come together into a single stream at  90 . The billet thrower and chute  23  and  24  of the previous embodiments (not shown here) is also fitted as a module. The feed arrangement is shown in part in  FIGS. 18A and 18B  at  91  and  92  so there are separate feed systems for each row but these have an inward taper to match lines  88  and  89 . The feed systems themselves may be conventional or may be configured as previously described in terms of each feed stage, although there will usually be additional feed rollers at  91  as there may be a slightly longer path to the billeter. The feed systems are removable as a pivoting module as before and they also float as before. The taper ensures that the chassis and the parts making up the harvester may still all be fitted into a 40 foot shipping container. The skilled person will readily understand all the optional variations. 
     It will be further appreciated that the main objective of one form of the invention is to collect cane juice that is inadvertently left behind by the prior art harvesters when trying to separate cane stalks and leave trash, so whole cane as referred to here is not to be taken literally but means substantially whole cane as captured by the present invention compared to the prior art, since inevitably some of the cane leaves and stalks will be left infield no matter how efficient a process is. Whole cane effectively herein means greater efficiency overall rather than literally whole cane plants.