Modular mixed dryer for grain and ear cereals

Abstract

Mixed dryer (100) for corn or the like, suitable for both grains and cobs, comprising a plurality of modules (50), each module comprising at least one drying cell (10) intended to receive the corn, a hot air generator (30) and its air distribution network (35) for sending the hot air into said cell, said dryer comprising an automatic filling system (20) configured to uniformly fill each cell (10), each cell (10) comprising on its bottom at least one drying duct (16) perforated with several holes and crossed by the hot air blown by said generator, said holes having a variable spacing along said duct so as to ensure a constant air flow passing through the corn, the dryer further comprising an air recycling tunnel (352) for reinjecting used, slightly humid air into the cell. Figure for abstract: figure 1

Description

Title of the invention: Mixed modular dryer for grain and ear cereals Technical field

[0001] The present invention belongs to the field of systems for drying cereals, in particular corn, and relates more particularly to a mixed (or multipurpose) modular dryer for cereals which may be in the form of grains or ears.

[0002] The invention finds a direct, but not exclusive, application in the drying of corn. State of the art

[0003] Grain dryers have been known for a long time.

[0004] These systems are used in agriculture to reduce the moisture content of grain after harvest. Drying corn, for example, is a crucial step because high moisture can lead to mold growth and grain deterioration, which affects both the quality and market value of the product.

[0005] There are different types of corn dryers, including batch dryers and continuous dryers. Batch dryers process corn in separate batches and often require the grain to be manually unloaded and loaded. Continuous dryers, on the other hand, allow the grain to pass through the dryer in a constant stream, which is more efficient for large operations.

[0006] The drying process typically uses hot air to evaporate moisture from the grain. The temperature and airflow must be carefully controlled to avoid damaging the grain. Drying can be accomplished using a variety of energy sources, including natural gas, propane, electricity, or even renewable energy sources like biomass.

[0007] The design and efficiency of corn dryers have evolved over time, with improvements in reducing energy consumption, increasing drying capacity, and minimizing grain damage.

[0008] We generally know of bin dryers with Ampliroll arms (registered trademark). These are bins with ventilated bottoms, placed directly on the ground, mainly for drying cereals.

[0009] These skips generally offer small volumes, due to the regulatory dimensions authorized on the road, and require numerous tedious handling operations using a lifting hook (removal from the truck, placing on the ground, putting back on the truck, etc.).

[0010] There are of course other less rudimentary solutions for drying cereals and corn in particular.

[0011] Document FR2445101Al describes, for example, a blowing dryer for corn in ears.

[0012] As shown in the above-mentioned document, in the case of corn and other similar cereals, the dryers are only compatible with one form of corn, in grain or in cob, but not both at the same time.

[0013] Drying corn on the cob is usually done on an inclined plane, because due to the gap structure and consistency of the cobs when packed, they can fill the inclined plane fairly uniformly (with a substantially constant filling height) and be easily evacuated by gravity via a trapdoor located at the bottom of the inclined plane.

[0014] On the other hand, in the case of grains, inclined planes prove unsuitable because the grains tend to accumulate at the bottom of the slope of the inclined plane during filling. This produces a settling of the grains in the deepest area and, in return, a lower filling thickness at the top of the inclined plane. Hot air naturally tends to escape through the areas of low thickness, thus creating persistent humidity in the areas of great thickness. This can quickly lead to rotting of the product.

[0015] Furthermore, due to observed climate changes, with increasingly hot summers in grain-producing regions, harvest windows have become shorter. Therefore, to speed up harvests, producers are harvesting corn in grain form with combine harvesters rather than picking it in cobs and therefore need a dryer suitable for both cobs and grains.

[0016] To the applicant's knowledge, there is currently no versatile system capable of drying both ears and grains.

[0017] As mentioned above, corn dryers are designed specifically for one form or the other, due to differences in drying requirements. Corn kernels and corn cobs have different moisture levels, densities and airflow requirements, which makes their simultaneous drying in a single piece of equipment complex.

[0018] Document US4212115 describes a corn drying apparatus with a drying area divided into several compartments and an upper and lower plenum system. This system allows the hot air to be directed either from top to bottom or from bottom to top through the corn, which is essential to achieve a uniform moisture content in the corn. The design of this apparatus also includes a perforated floor for better air circulation and doors allowing manual control of the air passage.

[0019] This solution is designed to optimize the drying of corn grains, in particular with hot air circulations adapted to the consistency of the grains and their specific humidity levels. Summary of the invention

[0020] The present invention aims to overcome all or part of the drawbacks of the prior art set out above by proposing an innovative solution making it possible to dry corn both in grains and in cobs.

[0021] An objective of the invention is therefore to propose a versatile, efficient and energy-saving system.

[0022] To this end, the present invention relates to a dryer for a product such as cereals or the like in two different forms, grains and ears, comprising a plurality of modules, each module comprising at least one drying cell intended to receive the product, a hot air generator and its air distribution network for sending the hot air into said cell.This dryer is remarkable in that it comprises an automatic filling system configured to uniformly fill each cell, that is to say to a substantially constant height, in that each cell comprises on its bottom at least one drying duct perforated with several holes and crossed by the hot air blown by said generator, said holes having a variable spacing along said duct so as to ensure a constant air flow passing through the product, and therefore uniform drying, and in that it further comprises an air recycling tunnel to recover the used air which is partially loaded with humidity and reinject it into the cells with or without reheating.

[0023] Due to the uniform filling and the hot air flow and temperature adjustments allowed, the dryer is versatile and adapts to both grains and ears, ensuring uniform drying in both cases.

[0024] According to one embodiment, each module comprises two adjacent cells and a single hot air generator, the distribution network comprising a primary channel with two branches to supply the two cells.

[0025] Advantageously, each cell comprises a motorized horizontal hopper provided with a conveyor belt for evacuating the product towards a recovery conveyor located at the rear of the dryer.

[0026] More particularly, each cell comprises a guillotine hatch, the opening of which allows the product to be evacuated by gravity onto the recovery conveyor, said hatch having one or more automatically controlled positions, each of which corresponds to a certain degree of flowability of the product.

[0027] According to one aspect of the invention, each cell comprises at least one flap at the level of its upper opening and the upper registers connected to the recycling tunnel, the dryer being configured to operate in an open circuit, in which the shutter is open and the upper registers closed, or in a closed circuit, in which said shutter is closed and said registers are open to reinject the used air into the recycling tunnel.

[0028] More particularly, the recycling tunnel is common to all cells.

[0029] According to an advantageous aspect, a sealing strip is placed laterally between the drying duct and the bottom of the cell, said strip defining a gap to allow a layer of hot air to pass through and preventing the product from passing through.

[0030] According to one embodiment, each hot air generator comprises several burners for adjusting the temperature of the hot air.

[0031] The hot air generators also include a fan to blow the hot air into the drying ducts.

[0032] Advantageously, the modules can be connected to each other without any masonry footprint on the ground.

[0033] The fundamental concepts of the invention having just been set out above in their most elementary form, other details and characteristics will emerge more clearly on reading the description which follows and with reference to the appended drawings, giving by way of non-limiting example an embodiment of a mixed dryer for cereals, in accordance with the principles of the invention. Presentation of the drawings

[0034] The figures are given purely for illustrative purposes for a better understanding of the invention without limiting its scope. The various elements may be represented schematically and are not necessarily to scale. Throughout the figures, identical or equivalent elements bear the same numerical reference.

[0035] It is thus illustrated in:

[0036] [Fig-1]: a perspective view of a mixed dryer according to an embodiment of the invention;

[0037] [Fig.2]: another perspective view, rear, of the mixed dryer showing the conveyor for recovering the dried product;

[0038] [Fig.3]: an exploded view of a drying module of the mixed dryer;

[0039] [Fig.4]: a partial view of the dryer, showing the detail of a cell;

[0040] [Fig.5]: a rear perspective of a dryer cell;

[0041] [Fig.6]: a front perspective of a dryer cell;

[0042] [Fig.7]: a partial view of the dryer, showing the detail of the filling system;

[0043] [Fig.8]: a truncated view of the isolated filling system;

[0044] [Fig.9]: a partial view of the dryer, showing the detail of a hot air generator and its air distribution network;

[0045] [Fig. 10]: a perspective of a dryer cell, showing the drying ducts at the bottom of the cell;

[0046] [Fig. 11]: a section of the cell of [Fig. 10] according to plane A - A. Detailed description of embodiments

[0047] It should be noted that certain technical elements well known to those skilled in the art are recalled here to avoid any insufficiency or ambiguity in the understanding of the present invention.

[0048] In the embodiment described below, reference is made to a mixed modular dryer, mainly intended for drying cereals in different shapes or morphologies (grains and ears) such as corn. This non-limiting example is given for a better understanding of the invention and does not exclude the use of the dryer for drying other materials, in particular hay, wood chips and the like.

[0049] In the remainder of the description, the terms “cereals” and “product” refer indifferently to corn.

[0050] Figures 1 and 2 show a mixed dryer 100 comprising a plurality of juxtaposed drying cells 10, a motorized filling system 20, placed above the cells and allowing each of them to be filled at a time with the cereals to be dried, hot air generators 30 and their air distribution and recycling networks 35, located at the front of the cells 10 and allowing a flow of hot air to be blown into them, and a recovery conveyor 40 located at the rear of the cells 10 to evacuate the dried cereals outside the dryer 100.

[0051] The mixed dryer 100, due to its plurality of cells 10 and hot air generators 30, is in the form of a modular system adaptable according to the needs of the users. Indeed, the mixed dryer 100 comprises several drying modules 50 each consisting of two adjacent cells 10 and a hot air generator 30 with its air distribution and recycling network 35 supplying the two cells.

[0052] According to the illustrated embodiment, the mixed dryer 100 has six modules 50, one of which, located at the end, is delimited by a broken line in [Fig.l].

[0053] [Fig. 3] represents an exploded view of a drying module 50, to better visualize its various components.

[0054] This modularity allows the mixed dryer 100 to adapt to different drying capacities in terms of volumes of cereals processed, but also to adapt to different spaces by the possibility of arranging the modules in different ways: in one or more rows, parallel or perpendicular, etc. This is all the more simpler than the 100 mixed dryer, does not require any masonry footprint and can be installed and fixed using quick fixing methods.

[0055] In addition, the mixed dryer 100 may initially comprise one or a few modules 50, to which additional modules may be progressively connected depending on an evolving industrial need, for example.

[0056] [Fig. 2] shows the mixed dryer 100 in rear view and allows a better visualization of the recovery conveyor 40 which allows the dried product to be evacuated at the outlet of the cells 10.

[0057] Figures 4 to 6 show the drying cells 10 in more detail.

[0058] Each cell 10 has a parallelepiped shape of rectangular section, reminiscent of that of a conventional skip, and comprises a horizontal hopper 11 which forms its bottom, a guillotine hatch 12 allowing the cell to be emptied when the belt of the hopper 11 starts rotating, flaps 13 at the level of the upper filling opening of said cell, ventilation and air intake registers, lower 14 and upper 15, and drying conduits 16 passing through the cell 10 lengthwise opposite the lower registers.

[0059] The cells 10 thus constitute the space for drying the cereals and allow the execution of different programmed drying cycles as explained below.

[0060] The hopper 11, according to one embodiment of the invention, uses the sealing principles described in patent FR3091860 in the name of the applicant.

[0061] This patent in fact describes a belt conveyor, for the transport of bulk products, comprising a chassis, a conveyor assembly, and a motorized drive device, the conveyor assembly comprising a plurality of transverse pallets coupled to at least one chain driven by a motor pinion of the drive device and on which a flexible conveyor belt is fixed, said conveyor comprising at each lateral edge of the conveyor assembly: a sliding base placed above the ends of a portion of the transverse pallets and below the conveyor belt, and a sealing block fixed to a side wall of the conveyor and pressing the conveyor belt against said sliding base.

[0062] The hopper 11 allows, by rotation of its horizontal conveyor belt, to direct the dried product towards the outlet of the cell 10. The movement of the conveyor belt of the hopper 11 is then accompanied by the progressive opening of the guillotine hatch 12.

[0063] The guillotine hatch 12 is mounted to slide at the rear face of the cell 10, in a direction substantially perpendicular to the hopper 11, and allows, when rising, passage to the dried product carried by the rotation of the hopper so that it can be evacuated by the recovery conveyor 40.

[0064] The guillotine hatch 12 has, for example, several automatically controlled opening heights, each corresponding to a type of product, in order to optimize the emptying operation of the cell 10. In fact, cereals do not have the same flowability (or viscosity), so that the choice of a suitable opening height makes it possible to avoid overflow of the product during emptying.

[0065] Of course, the guillotine hatch 12 remains in the closed position during the filling of the cell 10 with the product to be dried, which filling is carried out via the upper opening of the latter with the flaps 13 open or partially open.

[0066] The shutters 13, according to the illustrated embodiment, are rolling and arranged in a symmetrical pair on each cell 10.

[0067] Indeed, the two rolling shutters 13 of each cell 10 are mounted on a central axis 135 located substantially in the middle of the upper opening of said cell, perpendicular to it. Thus, in each cell 10, the rolling shutters 13 open from the ends towards the center of the cell, as indicated by the two opposite arrows in [Fig.6], by winding around the central axis 135 to be stored in a box provided for this purpose.

[0068] During drying, the flaps 13 can be open or closed depending on the nature of the drying cycle, which can be in an open circuit to allow air to escape to the outside or in a closed circuit to recycle the hot air partially saturated with humidity.

[0069] When filling the cells 10, the flaps 13 are necessarily open, totally or partially depending on the position of the filling system 20 which moves along each cell.

[0070] Figures 7 and 8 represent the filling system 20, according to an exemplary embodiment of the invention, comprising a transverse distribution conveyor 21 mounted to slide on a carriage 22, itself sliding on two longitudinal rails 225 running along the dryer 100, and a longitudinal conveyor 23 for transporting the product towards the transverse distribution conveyor.

[0071] The transverse distribution conveyor 21 ends with two pouring mouths 211 each opening into the cell 10, said mouths being astride the central axis 135 of the flaps 13 according to the example illustrated.

[0072] The transverse distribution conveyor 21 is motorized and slides along the carriage 22 to pour the product at different locations in the cell 10 and thus ensure the most uniform layer-by-layer filling possible, i.e. with a filling height that is substantially constant along the entire length of the cell. This makes it possible to avoid the formation of accumulation zones with different heights in which the drying will not have the same effect and will therefore not be uniform.

[0073] Preferably, the transverse distribution conveyor 21 describes an alternating “back and forth” movement along the cell 10, to achieve continuous filling. and homogeneous.

[0074] Furthermore, the cell 10 may include level sensors for sending filling instructions to the filling system 20 via a control system, making it possible to guarantee uniform horizontal filling.

[0075] Thus, whatever the quantity of product to be dried, the filling system 20 ensures uniform horizontal filling and therefore uniform drying of the entire product, including for low product heights in the cell.

[0076] Before it is discharged into the cell 10, the product arrives on the transverse distribution conveyor 21 via the longitudinal conveyor 23 which is provided with a ramp arranged so that the product falls exactly onto the transverse distribution conveyor 21.

[0077] As soon as the filling of a cell is complete, the drying cycle can begin thanks to the actuation of the hot air generator 30 supplying said cell.

[0078] [Fig.9] represents the hot air generator 30, according to an embodiment of the invention, comprising one or more burners not shown, a fan 31 and an air distribution and recycling network 35.

[0079] The air distribution and recycling network 35 comprises a primary hot air supply channel 351 and a recycling tunnel 352 common to all the cells.

[0080] Indeed, the recycling tunnel 352 is made up of connected sections and can therefore be extended in the event of adding additional modules to the dryer 100.

[0081] The hot air generators 30 may have different power sources. Preferably, the power source used is gas. Each generator 30 comprises several ignition ramps to provide different heating levels depending on the air flow rate required to dry the product.

[0082] It should be noted that to dry cereals and seeds, the air must be at a temperature between 38 and 40°C.

[0083] If the temperature is below this range, drying will take longer and therefore require more energy. On the contrary, if the air temperature is above the indicated range, drying may damage the grains.

[0084] Indeed, temperatures above 40°C can destroy the germ, which destroys the seed. On the other hand, for grains intended for food and not for seed, the condition of the germ is of little importance and drying can be carried out at higher temperatures.

[0085] For these adjustments, each hot air generator 30 comprises modulating valves making it possible to adapt the gas flow rate according to the air flow rate and the calories required for drying.

[0086] The fan 31 comprises a turbine for sucking in hot air and sending it into the primary supply channel 351.

[0087] This air suction can be carried out either in an open circuit or in a closed circuit to recover the air already used, which is warmer than the ambient (outside) air, via the recycling tunnel 352 which collects this air from the upper registers 15 of the cells 10.

[0088] The primary channel 351 is connected to the outlet of the fan 31 and has a shape which separates into two branches to distribute the flow of hot air over the two cells 10 of the same drying module 50 as shown in FIGS. 1 and 3.

[0089] The lower registers 14 then allow the flow of hot air to be admitted into the cells 10, thanks to their blades (in the form of shutters) controlled by servomotors to adjust the opening and therefore regulate the air flow.

[0090] If a cell 10 is empty, its lower registers 14 are closed, thus preventing the entry of hot air. Pressure sensors are provided to detect excess pressure at the closed cell and send an instruction for regulating the air flow sent by the fan 31.

[0091] The fan 31 is adaptive for this purpose and makes it possible to regulate the air flow in order to respect a preset set pressure at the start.

[0092] The drop in air pressure is necessarily accompanied by an adjustment of its temperature.

[0093] Hot air enters the cell 10 through the lower intake registers 14 and passes directly into the drying ducts 16.

[0094] Figures 10 and 11 show these conduits 16 in a cell 10.

[0095] According to the example illustrated, the cell 10 comprises four conduits 10: two central conduits and two lateral conduits.

[0096] Alternatively, depending on the size of the cell, the number of conduits may vary.

[0097] The conduits 16 are perforated sheets and thus form strainers for the hot air so that the latter rises into the cell and passes through the product to be dried.

[0098] Each conduit 16 has thousands of small holes distributed along its length, for example 3 to 4 mm in diameter to prevent the cereals from falling out. These holes are not visible in the figures.

[0099] In order to ensure the most uniform drying possible, the holes on each conduit 16 have a variable spacing. More particularly, the spacing becomes increasingly tighter towards the rear of the conduit 16, i.e. towards the guillotine hatch 12.

[0100] Indeed, due to the compression it undergoes in the duct 16, the hot air tends to exit more through the first holes of the duct, that is to say those located at the front of the duct, which promotes the drying of the product located at the front of the cell to the detriment of the product located at the rear. In order to compensate for this differential in the level drying, and therefore in the residual level of the humidity rate, the spacing of the holes along the conduits 16 is adjusted so as to obtain the same flow of hot air passing through the product and therefore, ultimately, uniform drying.

[0101] It should be noted that in the solutions of the prior art, there may be a difference in humidity level of the order of 4% between the front and the rear of the drying bin.

[0102] Furthermore, it is important that the seeds reach a predetermined humidity level, for example between 12 and 13%.

[0103] Thus, along each drying duct 16, the holes are distributed with a decreasing spacing from the front to the rear of the duct, i.e. according to the direction of penetration of the hot air into said duct. A numerical simulation makes it possible to fix the rule for decreasing this spacing to obtain the same flow rate of rising air throughout the cell.

[0104] Between the conduits 16 and the conveyor belt of the hopper 11, the lateral sealing is ensured by a flexible strip, for example made of plastic, which leaves sufficient play, of approximately 3 mm, making it possible to create an air gap which dries a part of the product located at this level and which could not be dried otherwise.

[0105] This sealing strip also ensures its sealing function to prevent the product from falling back.

[0106] It should be noted that a conventional flexible rubber flap would not work because it would trap air by pressing down with a pressure that prevents its release by the air flow.

[0107] By passing through the product contained in the cell 10, the hot air becomes charged with humidity and can either be evacuated through the upper opening of the cell with the flaps 13 open (open-air configuration) in the case of open-circuit drying, or be reinjected into the recycling tunnel 352 via the upper registers 15 in the case of closed-circuit drying.

[0108] The closed circuit is, for example, advantageous at the end of the season because the recovered hot air is not completely saturated with humidity and can be perfectly reused with or without reheating.

[0109] In open circuit, the roller shutters 13 are open to allow the evacuation of air, while the upper registers 15 are closed to prevent the penetration of air into the recycling tunnel 352.

[0110] Conversely, in a closed circuit, the roller shutters 13 are closed to maintain the used air in the circuit, while the upper registers 15 are open to recover this used air in the recycling tunnel 352.

[0111] The recycling tunnel 352 comprises inlet valves 353 at the inlet of each hot air generator 30. When these valves are open, the recovered air passes back into fan 31 to be sent into primary channel 351 and again into cells 10.

[0112] Advantageously, the dryer 100 as designed makes it possible to adapt to the needs of each cell depending on whether it is filled or not, with what type of product, depending on the external conditions, etc.

[0113] For example, if a cell has been in a drying cycle for several days, it will have a low humidity level. On the other hand, the last cell to be filled will have a higher humidity level. Therefore, the hot air already used and slightly loaded with humidity will be sufficient for drying or at least for the start of drying.

[0114] In addition, the air distribution is based on periodic sampling to measure the humidity levels, in order to adjust the program of each cell between drying in slightly humid recycled air or drying in dry air.

[0115] The sampling for humidity measurement can be automated in particular by means of the mobile trolley 22 on which automatic sampling means can be installed.

[0116] The recycling tunnel 352 is also equipped with depression sensors, making it possible to balance between the suction and the blowing of air in said tunnel.

[0117] In fact, the suction must not be stronger than the blowing by the fans so as not to create depressions.

[0118] In the event of detection of a depression, the flaps 13 of certain cells 10 can be opened to create an air intake and so that the fans 31 have another source of air to reduce the depression and rebalance the pressures in the recycling tunnel 352.

[0119] These operations, as well as the overall operation of the mixed dryer 100, are controlled automatically via a programmable controller.

[0120] Finally, the dry product is then conveyed by the recovery conveyor 40 to be processed in another part not concerned by the present invention (continuity to other ginning, calibration, etc. equipment).

[0121] It is apparent from the present description that certain non-essential elements of the dryer may be modified, replaced or deleted without departing from the scope of the invention defined by the following claims. For example, the filling, hot air generation and emptying operations may be carried out by alternative means and systems commonly used in the art.

Claims

Claims

1. Dryer (100) for a product such as cereals or the like in two different forms, grains and ears, comprising a plurality of modules (50), each module comprising at least one drying cell (10) intended to receive the product, a hot air generator (30) and its air distribution network (35) for sending the hot air into said cell, said dryer being characterized in that it comprises an automatic filling system (20) configured to uniformly fill each cell (10), in that each cell (10) comprises on its bottom at least one drying duct (16) perforated with several holes and crossed by the hot air blown by said generator, said holes having a variable spacing along said duct so as to ensure a constant air flow passing through the product, and in that it further comprises an air recycling tunnel (352).

2. Dryer according to claim 1, in which each module (50) comprises two adjacent cells (10) and a single hot air generator (30), the distribution network (35) comprising a primary channel (351) with two branches to supply the two cells.

3. A dryer according to claim 1 or 2, wherein each cell (10) comprises a motorized horizontal hopper (11) provided with a conveyor belt for discharging the product to a recovery conveyor (40).

4. Dryer according to claim 3, in which each cell (10) comprises a guillotine hatch (12) the opening of which allows the product to be evacuated by gravity onto the recovery conveyor (40), said hatch having one or more automatically controlled positions.

5. A dryer according to any preceding claim, wherein each cell (10) comprises at least one flap (13) at its upper opening and upper registers (15) connected to the recycling tunnel (352), said dryer being configured to operate in an open circuit, in which the flap is open and the upper registers closed, or in a closed circuit, in which said flap is closed and said registers are open to reinject the used air into the recycling tunnel.

6. A dryer according to any preceding claim, wherein the recycling tunnel (352) is common to all cells (10).

7. A dryer according to any preceding claim, wherein a sealing strip is placed laterally between the drying duct (16) and the bottom of the cell (10), said strip defining a gap to allow a blade of hot air to pass through and preventing the product from passing through.

8. A dryer according to any preceding claim, wherein each hot air generator (30) comprises a plurality of burners for adjusting the temperature of the hot air.

9. A dryer according to any preceding claim, wherein each hot air generator (30) comprises a fan (31) for blowing hot air into the drying duct (16).

10. A dryer according to any preceding claim, wherein the modules (50) are connectable to each other without any masonry footprint on the ground.

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