Patent Application
20110253820
The present invention relates to a crushing system with two sections of similar disks facing each other, which is connected to non-aligned axes so that the lower portions of the discs always remain united during the operation, the discs being kept in rotation thus compressing vegetable material for extraction of juice or liquids thereof. The supporting set from the disc sections is independent and has distinct characteristics, forming a fixed part and a movable part in order to adjust the vegetable mass to be compacted. This crushing system can be used alone or in series on suitable mounting according to necessity.
Another aspect of the present invention is related to the application thereof in the process of obtaining vegetable liquid, more specifically of sugar cane. In this case, the proposed crushing system also may be engaged in harvesting of sugar cane, being a part of such agricultural machinery either as one or as a series of such crushing units.
Thus, the technical field of this invention belongs to sugar cane and other biomass crushing and to the mechanical extraction of liquids from biomass. This aspect of agricultural technology is of interest for sugar and alcohol industries and industries manufacturing agricultural machinery or the like.
Processors for vegetable mass including crushing systems, specifically for sugar cane, correspond to a mechanical equipment usually based on the use of horizontal metal roller system which, when fed, crush the stems of plants by compression, extracting broth or liquid. Industrially, the systems are operated cylinders or rolls, alone or in series, as is the case of the milling process of sugar cane presented in the patent application PI0201995-7, where the pulp is directed to pass through a series of successively cylindrical mills (the mass generated in a first one feeding the next, thus completing cycles). Patent application U.S. Pat. No. 4,147,557 also discloses systems of plural coils in series. In said technological line, there are also examples of the use of cylindrical roller mills as disclosed in documents BRPI9305112-3 and BRPI07007221.
Most of the portable versions of mills for sugar cane are also based on the use of cylinders or rolls such as, for example, the model described in document BRMU7500595-6.
Another process of sugar cane crushing, although less common, is the one using a “worm” to press and crushing plants. Typically, this type of system uses a screw press cone (BRPI0303941-2), including the use conical rings at their ends, as shown in the patent application GB1375497.
The main limitations of grinding systems for vegetables with relative resistance, such as sugar cane, relate to the control of the pressing force regarding the initial characteristics of the vegetable mass input, especially for whole stalks or pieces of cane, including shredded sugar cane (bagasse). The feeding system for grinding rolls in this commodity, under conditions of high pressure in order to increase the efficiency of extraction of the liquid, leads to serious technological problems caused by the rejection of material or considerable loss of vegetable mass entering the system. The vast majority of patents related to roller systems seek to solve this problem, usually by adjusting the milling process, starting with little pressure and adjusting the compression as the bagasse is compressed (shredded cane). In this case, the milling process occurs in cycles, and so as to increase the extraction of sucrose, the bagasse must be wet (additional clean water) between each grinding cycle. This process becomes expensive, since it uses large amounts of water, besides being a lengthy process. To reduce the time spent in these extraction processes there have been proposed several types of arrangements between the cylinders in series (usually by three roller units—milling suits). However, the step of wet bagasse generated is still required for the grinding operation of the said invention, especially in industrial processes, to ensure the extraction of sucrose by repeated cycles of pressing resulting, in the end, in the formation of bagasse with an average of 50% humidity. However, there are less cycles, due to high extraction efficiency of liquid (lesser grinding time).
Some attempts to solve the problem of the rejection of the raw material in the grinding rolls are based on the introduction of a fourth roll, usually of smaller diameter and/or association between milling suits and/or introduction of sugarcane expansion prior to pressing, as described in the patent application BRPI0503537-6. The introduction of the grinding stage after cutting the cane into small pieces is also explored technologically. The selection of raw material is also used so as to increase concentration of sucrose during operation, either by use of more productive and resistant plants or by harvesting procedures, which despise the tip of the cane still in the field, such as the lateral cutting device used in sugar cane harvester machines described in the patent application BRPI0402356-0.
Another disadvantage of systems with horizontal rollers is linked to the high occurrence of idle mill, and for this reason, serial sets of rolls are being increasingly exploited, since they have smaller spacing between rolls wherein the installation of recirculation systems of bagasse is usually performed with the use of rotary mats. The patent application BRPI0201995-7 describes a process and a plant for grinding sugar cane with these characteristics in order to minimize the idle time of milling. Other embodiments are listed, as described in document BRPI0700722-1, referring to the mill for sugar cane and other biomass and consisting of a central roller surrounded by several others.
For the case of systems based on the use of “worm”, the main limitations of applying these systems, especially in the case of sugar cane, resides in the low extraction efficiency of liquids, although it can achieve high compression of biomass. Typically, these systems have a slower extraction process and require high-energy expenditure. Their implementation on an industrial scale is also impaired because they require an elaborate extraction chamber.
The present invention is based on the crushing by discs, more specifically on the use of sections of convex discs in rotation, operating so that the lower portions of the discs are always united, wherein the adjustment of the vegetable mass is to be controlled by means of compressed springs or a piston that pushes one of said portions of discs, preferably the one which has an inclined supporting axis. The layout of this system allows the use of high compression without the rejection of the raw material, especially the initial (pieces of cane) and defibered sugar cane, and consequently, a higher extraction efficiency of liquids. This crushing system is innovative, since the vast majority of the implementation of discs or rotating disc sections in the beneficiation process of sugar cane, usually relates to constructive aspects of cutters and/or cleaning and/or scrapers for sugar cane and also in maintenance processes in the farming moan systems, as discussed in several patent applications.
The grinding step established by this sections of convex discs system is similar to that already established in the art, wherein sugar cane is harvested, cleaned, cut into pieces and then taken to grind. As the crushing process can be considered the end of the agricultural process and the beginning of the industrial process, it becomes important to develop systems that are faster and have more efficient grinding, since the substance of interest present in the liquid extracted from the crushing, i.e. sucrose, has reaction pathways that lead the consumption thereof, undermining the amount obtained in the extraction process. In the living plant, said substance reaches a maximum over time, which then undergoes a decline, mainly due to polymerization reactions of sucrose, leading to the formation of cellulose (structure found in bagasse). This relates to the natural maturation and drying of the plant. To minimize losses, the cane is harvested when it has its maximum sucrose content and should be crushed immediately. In this sense, crop harvesters are being provided with vertical grinding systems. The vast majority of proposed grinding units, alone or in series, coupled with this type of harvesting is based on the use of cylindrical rollers. This is the case of patent documents BRPI9204012 and BRPI9704191-2-8 that allow direct extraction of the liquid in the farming.
Regardless of the provision of constructive grinding systems in harvesters, the abovementioned patents, related to the subject matter herein described, do describe the process of extracting the liquid from the cane comprising the steps of cutting, feeding, grinding and milling. In the cutting step, the sugar cane plantation is harvested, in the feeding step the cut cane is carried into the machine, in the grinding stage the cut cane is delivered and crushed into small pieces, in the milling step the cut cane is pressed and crushed several times, so as to allow the juice to be extracted from sugar cane. All propositions are based on increasing the efficiency of extraction. To get an idea of the importance of the crushing system in the production process, one should consider a plant producing 1 million gallons of alcohol per day, with deficiencies in milling that lead to a loss of 1% in the efficiency of extraction of liquids. This means a loss of 10,000 gallons/day of sugar cane juice, material that is no longer introduced into the production system.
The crushing system based on sections of convex discs, object of the present invention, provides different possibilities for applications and use as milling units in different ways, alone or in pairs or combined or as separate series (serial combination of individual units, in pairs or combined) in suitable mounting or coupled to the harvesters of vertical crops, mainly sugar cane. The main advantage of these systems is the possibility of working with high compression with low power consumption and the fact that it has a constructive structure lighter than those based on grinding by roller systems or “worm”, allowing the extraction of sucrose more efficiently in shorter amounts of time, virtually with no formation of excess capacity and no rejection in the milling of raw materials, i.e. mainly pieces of shredded sugar cane and sugar cane (bagasse). Moreover, these systems have low wear of grinding, since they do not work on friction. During operation, only the lower parts of the sections of the discs are assembled, allowing the use of a seal between them.
These advantages are important for implementation on harvesters. The milling of sugar cane farming, besides allowing better utilization of sucrose present in the plant, reduces risk of contamination of the broth, the reduction in the time of handling and in storage. In this case, the grinding also occurs in cycles, requiring a wet bagasse between one grinding cycle and the other, but with great reduction in the number of cycles. Since such a system presents no problems of rejection, especially with pieces of sugar cane, cane tips that are normally discarded during the cutting thereof, due to its low concentration of sucrose, may be used for grinding to obtain water to wet the mulch during milling cycles, helping to reduce water consumption during the production process, which is a trend imposed by the rational use of natural resources.
Another important factor is getting the bagasse crushed more quickly, said bagasse being in condition of becoming raw material for the production of biofuels such as ethanol or ethanol from lignocellulose, by the use of specific enzymes in addition to its traditional use in providing heat for boilers (by the burning thereof).
The present invention relates to the development of a crushing system by means of the compression of two sections of rotating discs. The compression is gradually distributed between the two sections of similar disks arranged frontally and connected to non-alligned axes, so that the lower portions of the discs always remain united during the operation or rotation. The supporting set of the sections of the disc is independent and has distinct characteristics, forming a fixed part and a movable part in order to adjust the vegetable mass to be compacted. This crushing system has structural features that allow its use in different forms: single, in pairs, or as an ensemble, enabling its use in series in suitable mounting in power plants or vertical crop harvesters such as sugar cane.
The surface of the two sections of discs allows different settings to increase the extraction efficiency depending on the raw material and/or the state thereof. For example, surfaces smooth or with soft waves or with small cutters are preferred for cane or pieces of cane, while surfaces with more structured mills are preferred for grinding the shredded cane (bagasse).
The invention may be better understood by means of the following detailed description of
The design of grinding systems of the present invention depends on the demand of production volume, varying in size so as to fit more simply in family units, up to its use in industrial plants as well as its solo use or in association sets (in series), in support systems near alcohol plants or harvesting machinery for sugar cane.
This example refers to an embodiment for a crushing system with compression having two sections of the rotating discs with just one inclined axis, mainly used for grinding sugar cane. This inclined axis rotation allows for the lower parts of sections of disc to always stay together, thus allowing the work with high compression with no rejection of raw material.
In the present invention, the two sections of convex discs (1) will compress the raw material into a rotary motion in which both sides of the disks will meet each other guided by two axes where at least one of them, is inclined relative the horizontal plane (as shown in
In the specific case of sugar cane the feeding of the process is necessarily made between the disc sections (1), thus lacking rejection since the stems are trapped and increasingly pressured by the gradual meeting of the chambers of the disc, drawing the fibers and extracting the juice. The sections of the discs work with the same rotation, supported by an internal repair or retainer (4) function thereof being to ensure that the raw material moves through the sections of discs. This retainer has two openings; a small upper opening (4.1) where the stand fits the support axis of the fixed and mobile parts ((3) and (3.1)) and one large opening on the lower portion (4.2), close to the union between the lower sections of the disk, wherein the liquid drains from the system (detailed in
FIG. 3.a shows a schematic of the inclined shaft support of the disc section (3) highlighting the cutters (5.3) that allow the displacement of the moving part of this crushing system by compression. Dotted lines highlight the close fit between the central opening (5) of the support bracket (2) with the edge of the inclined shaft sleeve (5.1). In the scheme of
FIGS. 5.a and 5.b show a schematic illustration of the convex disc section (1) used in the crushing system proposed, showing part of the support bracket (2), with its central opening (5), where the sleeves axis ((5.1) or (5.2)) is fixed, indicating also the retainer with its lower opening (4). The sections of the disk being used are quite resistant to compression, preferably formed of structural metal material such as stainless steel, iron alloys and steel alloys, or diverse structural polymeric material (resistant plastics), among others.
The surfaces of the sections of the mill drives have settings dependent on the raw material and/or state thereof (pieces of cane or shredded cane/bagasse), allowing the use of sections of convex disks with smooth surfaces and/or milled and/or corrugated. These variations are presented to increase the liquid extraction efficiency. Preferably, in the case of sugar cane in its natural state (pieces of cane), the two disks must have gentle undulations to force even more power and at the same time giving vent to the broth as far back as the sides. As for the case of shredded cane, as a second mill, wherein the fibers are embedded in liquid—usually water—the disc should have milling (lengthwise and parallel to the perimeter of the disks) to help force the return of the liquid at high pressure among the fibers to draw more sucrose. In both states of the raw material, the liquid cannot find passage at the maximum peak pressure point of the discs.
The operation of the crushing by compression of the two sections of convex disks in rotation (1) has at least one of the axes inclined (to allow closure only at the bottom), but with both in the same plane. The compression is forced by the moving part, comprising the inclined shaft (3), getting power by any of the hydraulic, mechanical or electrical means, with compression being determined by the piston, springs and the like. It is based on two sections of convex disks that are alike (1), working in rotation, stuck to their respective support (2) of the fixed and movable part, which in turn are coupled to their corresponding axes (axes (3.1) and (3), respectively). Both axes are fixed, only the support of one of the axes is mobile, which suffers the action of an actuator compression (e.g., springs) that are meant to push the support section of the inclined disc and therefore push the disc sections against each other, both in rotation, determining the necessary compression to crush the material. The movement of the inclined shaft (3) to support (2) is made by longitudinal milling (5.3) present within the support shaft and the external part thereof. Both discs work with the same rotation, supported by an internal retainer (4) which serves to ensure that the raw material moving through the disc sections, during compression. The entire assembly mounted between the two shafts must be inserted into casing structures or structural coverage or housing ((13) and (14)). This envelope has the function of assisting the direction of the feeding stream and of the extracted fluid, and avoids direct contact with the mill, providing operational safety, and also helping to reduce the contamination of the liquid obtained. The retaining element (15) is an external repair of the mill, with the function of retaining the residual liquid on the outside of the chambers of the discs before they open.
The crushing system based on compression between two disc sections also provides other minor components such as pulp cleaner (12), retractable feeder (16) and feeding driver (11).
The feeding director (11) is attached to the support bracket between the axes (10), constituting a structure inclined to direct and continued feeding and for separating the feeding vegetable matter from the output of bagasse. Moreover, it prevents the plant material from being deposited into the support bracket (10). This driver is positioned frontally to the feeder (16), preferably being made of resistant flexible material (e.g. rubber) for pieces of cane, and metallic structural material (e.g. metal—such as iron, metal alloys, like steel, among others) for shredded sugarcane bagasse.
The pulp cleaner (12), known in the art, has the function of cleaning disc sections, extracting the pulp of the overall grinding system. This cleanser is fixed and attached to the support bracket between the axes (10), forming small bar arranged perpendicular to the sections of the rotating discs and placed opposite the feed assembly ((1) and (6)).
The retractable feeder (16), known in the art, is attached to the housing structure or structural coverage (13), consisting of a shaft that supports fixed structural elements (such as blades, caps, forks, etc.), protected by rotary wrappers that expose these structural elements only during the compression of raw material into the mill.
This example refers to an embodiment for a crushing system with compression having two sections of the rotating discs with both axes inclined, mainly used for grinding sugar cane, as shown in
Both the structural constitution and functioning of this system are the same as shown in
Other accessories are provided to complete this grinding system, such as pulp cleaner (12), retractable feeder (16) and housing structures or structural coverage ((13) and (14)), which involves the whole system, helping the direction of feeding flow and the liquid extracted by means of constructive units.
This example refers to a proposal for a dual system of crushing by compression having two sections of the rotating discs with inclined axes, which is mainly used to grind sugar cane as shown in
In this example, the two sections of internal discs are fixed on the same route, called the inner shaft (3.2), while the other two external drives sitt on two axes inclined to the horizontal plane of the inner shaft (3).
The structural constitution and functioning of this system are the same as shown in
In the milling process, the bagasse generated in one system is later wet and directed to pass through another mill, and so on, for being used in its isolated form or by feeding the next set of double milling in the case of a serial form.
This example refers to an embodiment for a crushing system combined with compression of three sections of the rotating discs with inclined axes (double crushing system simplified or reduced), mainly used for grinding sugar cane, as shown in
The structural constitution and functioning of this system are the same as shown in
In the milling process, the bagasse generated in one system is later wet and directed to pass through another mill, and so on, for being used in its isolated form or by feeding the next set of double milling in the case of a serial form. Also, there is provided the use of a combination between the disc sections attached to the compression fit therebetween formed by a convex section with a concave disc, having also variant surfaces (smooth, undulating, milled, and other structural millers among others).
The grinding systems presented in the present invention and described in Examples 1-4 can be used in manufacturing plant harvesters with light harvester for harvesting and milling plants combined in the same equipment, not being restricted to the harvesting and milling of sugar cane, since it can be applied to any vegetable or grain of interest, such as corn, soybeans, among others.
| Number | Date | Country | Kind |
|---|---|---|---|
| PI0805556-4 | Dec 2008 | BR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/BR2009/000442 | 12/1/2009 | WO | 00 | 7/11/2011 |
