TORRE DE SECAGEM DE GRÃOS

Abstract

Grain drying tower. A drying tower (10) of a grain dryer (1) is described which exhibits greater energy efficiency and greater uniformity of grains after drying. To this end, each module (20) of the tower (10) comprises a front panel (21) and a rear panel (22), and between said front (21) and rear (22) panels are provided two lines of ducts (23) alternating in elevation, each of said ducts (23) having an irregular hexagon shape with a projecting upper vertex (30), and below each of said ducts (23) is also provided a partition (24), in the form of a flat plate that is fixed to the respective front (21) and rear (22) panels of each module. In particular, each of said partitions (24) comprises, at its respective lateral ends, cutouts (25) in the regions adjacent to the front (21) and rear (22) panels. a particularly advantageous dimension is also described for each module (20).

Description

GRAIN DRYING TOWER

[001] The present invention relates to a vegetable grain dryer and specifically to a drying tower for drying vegetable grains after harvesting and before storage or industrial processing thereof. More particularly, the invention relates to a drying tower comprising a series of drying modules, which define said drying tower of the grain dryer and in which the grain mass comes into contact with a flow of heated air. State of the Art

[002] As is known in the art, vegetable grains, when harvested from the field, generally have a moisture content higher than recommended for storage or industrial processing. For this reason, they are subjected to a drying process where the excess moisture is removed. In general, grain dryers with various construction forms are used to dry the grains, with different types of drying towers, air flows, fan arrangements and positions, among other items. Conventionally, these drying towers are composed of, or defined by, a stacking of drying modules, a solution that facilitates the construction of the drying tower, which, depending on its capacity, can reach several tens of meters in height.

[003] Thus, document CA 2882505 teaches a grain dryer whose drying tower, internal to the dryer, and in which contact occurs between the wet grain mass and the heated drying airflow, is formed by a plurality of superimposed modules and in such a way that the resulting tower assumes a cylindrical shape.

[004] Documents US 6035544 and US 20120011736 illustrate specific configurations for grain passage ducts, aiming to increase the efficiency in grain drying and, therefore, a reduction in the energy consumption of the grain dryer. These solutions also seek the integrity of the grains being dried, i.e., a lower rate of grain breakage during the drying process.

[005] Documents DE 10357410 and WO 2009000812 teach drying towers whose ducts have a shape similar to that of the present invention, wherein Petition 870200133322, dated 10 / 22 / 2020, page 11 / 32 2 / 8 These grain dryers also aim for greater efficiency in heat exchange between grains and airflow, in order to increase the efficiency of the drying tower and reduce energy consumption.

[006] As is clear from the analysis of the aforementioned art documents, increasing the efficiency of grain drying towers, from an operational point of view, depends on efficient control of the feed and discharge speed of the grains being dried, and on control of the characteristics of the drying airflow (temperature, speed, humidity, etc.), always as a function of the characteristics of the grains being dried in the tower. Obviously, such operational conditions can be managed, on a case-by-case basis, by qualified technicians and / or automated systems, always taking into account the conditions of the entities involved in grain drying.

[007] On the other hand, even if the drying procedure adopts the best possible operational parameters, the efficiency limit of the drying tower is conditioned by the constructive characteristics of the drying tower itself. Thus, in addition to appropriate dimensions for the modules, ducts, and channels through which the grain mass and hot air flow move, it is also important that the internal geometry of these components of the drying tower core avoids, at all costs, the accumulation of grains at certain points, or the generation of zones in which the hot air flow is partially obstructed. In other words, all flows involved in the drying process (whether the various grain flows moving through respective channels, or the hot air drying flows) must be as homogeneous as possible so that the dried grains are dried in an equally homogeneous way. Objectives and Summary of the Invention

[008] Thus, a primary objective of the invention is a grain dryer whose drying tower is formed, or defined by drying modules, with improved geometries and capable of minimizing points of grain accumulation and obstruction to the passage of drying airflow.

[009] These and other objectives are achieved from a drying tower for a grain dryer, comprising a series of parallelepiped modules, Petition 870200133322, dated 10 / 22 / 2020, page 12 / 32 3 / 8 of equal dimensions to each other, coupled and stacked relative to one another, each module comprising a front panel and a rear panel, with two alternating lines of ducts between said front and rear panels, each duct having an irregular hexagonal shape with its upper vertex projecting, and below each duct a partition is provided, in the form of a flat plate that is fixed to the respective front and rear panels of each module. Each of said partitions comprises, at its respective lateral ends, cutouts in the regions adjacent to the front and rear panels. In particular, said cutouts have a quadrangular shape.

[0010] In a particularly advantageous embodiment, in the drying tower, each module has a width L=A, a height H of 0.262A and a depth P of 0.9524A. Furthermore, each module comprises ducts, arranged in alternating elevations, with a lateral displacement DL corresponding to 0.167A and an elevation displacement DC of 0.131A, and each duct has a length CD of 0.95A, a height HD of 0.1A and a width LD of 0.12A, and the aforementioned upper vertex is defined from a height HV of 0.06A and a half total width LV of 0.06A. Additionally, each module comprises a partition with a length CDV of 0.95A and a height HDV of 0.27A, and the cutout is presented as a square-shaped opening with an edge of 0.12A.

[0011] As surprisingly discovered by the inventors, incorporating cutouts at the ends of the partitions, respectively next to the front panel and the sides of the drying tower, prevents the accumulation of grains and impurities in these regions, resulting in a more homogeneous flow of grains and, therefore, a more homogeneous drying of the grain mass. Brief Description of the Figures

[0012] The present invention will be better understood from the detailed description that follows, of a preferred and non-limiting embodiment thereof, which is based on the attached figures, provided by way of illustration and not limitation of the invention, in which: Figure 1 is an illustrative view of a vegetable grain dryer, as is known. Petition 870200133322, dated 10 / 22 / 2020, page 13 / 32 4 / 8 in art; Figure 2 is a perspective view of a grain dryer, partially sectioned to allow visualization of the drying tower, according to the invention; Figure 3 is a perspective view of a drying module according to the invention; Figure 4 is a perspective view of the module in Figure 3, with one of the panels removed; Figures 5A and 5B illustrate the partitions of each of the drying modules, respectively incorporated into the module and isolated; Figures 6A-F illustrate various views of the drying module, with a particularly advantageous dimensional representation of the invention; Figures 7A and 7B are photos illustrating a grain duct of a drying tower, according to the invention; Figures 8A and 8B are photographs illustrating a grain duct of a drying tower, according to the state of the art, illustrating the accumulation of grains; and Figures 9 and 10 represent comparative energy efficiency graphs of the dryer according to the invention and dryers according to the state of the art. Description of a Preferred Embodiment of the Invention

[0013] In accordance with the attached figures, and in particular with regard to figures 1 and 2, a vegetable grain dryer (1) is composed of a structure (2), inside which is arranged a drying tower (not visible in this figure), in addition to the other components of the dryer, such as air passage chambers, etc., according to the configuration adopted for it. At the top of the dryer (1) there is a product reservoir (3), which has the function of keeping the drying tower (10) completely full of product, as well as compensating for the volume loss that occurs during the drying process. In the case of the present invention, an automatic level control is provided which, interconnected to the electrical control panel, controls the maximum and minimum volume of the reservoir (3). Furthermore, the reservoir (3) is fed by means of a hopper (4) located above it, as is also usual in the art.Finally, the dry grains exit through the bottom of the dryer, via the discharge funnel (5). Petition 870200133322, dated 10 / 22 / 2020, page 14 / 32 5 / 8, and the collection and direction of these can be done through various means known in the art.

[0014] The drying tower (10) is formed by ducts, panels and partitions (specific description below), which form several columns of grains. A certain volume of heated air is forced through the grain columns, providing moisture removal from the grains through mixed airflow. The air is forced through the grain layer by means of fans (14), and the air is directed to the tower through air chambers. The air is heated by a heat generator (not shown), which can be constructed according to the type of fuel to be used (wood or rice husk, among others). The tray discharge system (16), which is mounted below the drying tower, controls the speed of movement of these grains in the drying tower (10).

[0015] During the passage of air through the grains, impurities and residues, such as dust, husks, and others, are carried along, some of which are decanted in the exhaust chamber, and the remainder is directed to the exhaust fans (17). As an option, there is a filtration system (18) for this air with particles, thus collecting this particulate matter which is directed through a duct (19). The material decanted in the lower part of the exhaust chamber is aspirated by a system of hoods; this impurity is transported together with the impurities collected in the intake system of the dryer's exhaust fans (14) and sent to a cyclone, in a known manner.

[0016] When the grains have the appropriate moisture content for storage or processing, they are discharged from the dryer via the discharge system (16), discharge funnel (5) and lower conveyor, and are then sent to other processes.

[0017] With regard specifically to the drying tower (10), it is composed and defined by a series of modules (20), identical to each other, coupled and stacked in relation to each other, which are specifically illustrated in figures 3-6 and constitute the specific object of the present invention.

[0018] In particular, each module (20) is geometrically defined as a parallelepiped structure, comprising a front panel (21) and a back panel. Petition 870200133322, dated 10 / 22 / 2020, page 15 / 32 6 / 8 (22) . In addition, the upper and lower surfaces of each module (20) are open to allow the transverse and downward passage of heated air and grain flows. The side surfaces of each module are also open, with each module arranged laterally complementing and giving functional continuity to each of the module rows. The final side closure is made by the side wall of the grain dryer structure (2) itself (1).

[0019] Between said front (21) and rear (22) panels of each module (20) are arranged two lines of ducts (23) alternating in relation to the height of the dryer (1). As best illustrated in figure 6B, each of said ducts (23) has an irregular hexagon shape with a projecting upper vertex (30). This shape of each duct (23) assists in the continuous and regular downward movement of the grain mass being dried.

[0020] In addition, and below each of said ducts (23), a partition (24) is also provided, in the form of a flat plate that is fixed to the respective front (21) and rear (22) panels of each module. As is known, the presence of these partitions (24), together with the ducts (23), inside the drying tower (10), establishes individualized descending paths for the grain mass, thus equalizing the amount of grain in each path, resulting in greater uniformity in the drying of the grains.

[0021] Notwithstanding the advantages gained by said partitions, they cause a recurring problem in all dryers known in the art, namely, the accumulation of grains and impurities in the internal regions and adjacent to said front and rear panels of each module. Figures 8A and 8B are photos of a dryer equipped with partitions that extend the entire distance between the front and rear panels, as per the dryers in the art. In these images it is possible to identify a certain accumulation of grains (in this case, corn) in the internal regions of the module and adjacent to the panels (in this case to the front panel). The arrows identify said accumulations.

[0022] In order to solve the specific problem and, concomitantly, increase the quantitative regularity of the downward flow of grains at any internal point of the module, it was discovered by the inventors, and thus constitutes the main object of the invention, Petition 870200133322, dated 10 / 22 / 2020, page 16 / 32 7 / 8 that such accumulations of grains and impurities can be completely avoided simply by reconfiguring the shape of the partition.

[0023] As best illustrated from figures 4 and 5, said partition (24), according to the present invention, is defined by a flat plate and laterally provided with cutouts (25) in the regions adjacent to the front (21) and rear (22) panels of each module (20).

[0024] More specifically, each partition (24) is defined by a central, flat plate (26), with a recess (27) at its top, at the ends of which project respective tabs (29) also for fixing the partition (24) to the front (21) and rear (22) panels of the module (20). In addition, on the lower portion of the partition (24), a series of tabs (28) project, angularly spaced apart from each other, so as to perform the positioning recess of each partition on said upper vertex (30) projecting from the duct (23) located immediately below each partition (20). Furthermore, said recesses (25) are preferably rectangular in shape and are made in such a way as to maintain the integrity and structural support function of the upper recess (27). Alternatively, these cutouts can take on shapes other than rectangular, depending on the specific operating characteristics of the dryer, the type of grain, the working volume, among other parameters.

[0025] Furthermore, and in addition to the inventive features as set out above, the inventors also found that, from a specific dimension, it is possible to obtain a markedly superior quality in the drying of the grains compared to the state of the art. This concept can be better illustrated from figures 6A-F, in which the module (20) is shown, which has a width A for its front panel (21), or rear panel (22).

[0026] In this condition, the module (20) is defined as having a height H of 0.262A and a depth P of 0.9524A.

[0027] Based on a defined volume for the module (20), the ducts (23) are, as mentioned, arranged in alternating dimensions (see in particular figure 6B), with a lateral displacement DL corresponding to 0.167A and a dimension displacement DC of 0.131A. Petition 870200133322, dated 10 / 22 / 2020, page 17 / 32 8 / 8

[0028] Furthermore, each of the ducts (23) (see figures 6C-6E) has a length CD of 0.95A, that is, slightly less than the depth P of the module, allowing its fitting and fixing in the internal volume of this module. The height HD of the duct is 0.1A while its width LD is 0.12A. Finally, the aforementioned upper vertex (30) is defined from a height HV of 0.06A and a half total width LV of 0.06A.

[0029] Finally, and as illustrated in figure 6F, the aforementioned partition (23) has a CDV length of 0.95A and an HDV height of 0.27A. The cutout (25), in this specific solution, is presented as a square-shaped cutout with an edge of 0.12A.

[0030] Based on the specific solution, as defined above, the inventors conducted some comparative tests with existing equipment on the market. Figures 9 and 10 illustrate comparative graphs of energy consumption between equipment according to the invention (Invention) and conventional equipment (EQ02 and EQ01), which clearly shows the greater efficiency of the present equipment in terms of energy consumption, both in terms of calories consumed per kg of evaporated water and in terms of horsepower per dry ton.

[0031] Furthermore, and in addition to the greater energy efficiency resulting from a drying tower (10) for a grain dryer (1) as set out above, the present solution also increases the quality of the drying obtained. Since the accumulation of grains along the inner walls of the drying tower is eliminated, the grains can flow more uniformly and, as a consequence, reside inside the drying tower for a more uniform time, resulting in greater uniformity of the dried grains.

Claims

1. Drying tower (10) for a grain dryer (1), comprising a series of parallelepiped modules (20), dimensionally equal to each other, coupled and stacked in relation to each other, each module (20) comprising a front panel (21) and a rear panel (22), between said front (21) and rear (22) panels there are two lines of ducts (23) alternating in height, each of said ducts (23) having an irregular hexagon shape with a projecting upper vertex (30), and below each of said ducts (23) there is also a partition (24), in the form of a flat plate that is fixed to the respective front (21) and rear (22) panels of each module, characterized by each of said partitions (24) comprising, at their respective lateral ends, cutouts (25) in the regions adjacent to the front panels. (21) and rear (22).

2. Drying tower, according to claim 1, characterized in that said cutouts have a quadrangular shape.

3. Drying tower, according to claim 1, characterized in that each module (20) has width L=A, height H of 0.262A and depth P of 0.9524A.

4. Drying tower, according to any of the preceding claims, characterized by each module (20) comprising ducts (23), arranged in alternating elevations, with a lateral displacement DL corresponding to 0.167A and an elevation displacement DC of 0.131A, and with each duct (23) having a length CD of 0.95A, a height HD of 0.1A and a width LD of 0.12A, and said upper vertex (30) being defined from a height HV of 0.06A and a half total width LV of 0.06A.

5. Drying tower, according to any of the preceding claims, characterized in that each module (20) comprises a partition (23) with a length CDV of 0.95A and a height HDV of 0.27A, and the cutout (25) is presented as a square-shaped opening, with an edge of 0.12A.

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