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Title:
HEAT EXCHANGER, HEAT GENERATOR AND EQUIPMENT FOR DRYING BULK PRODUCTS
Document Type and Number:
WIPO Patent Application WO/2018/211423
Kind Code:
A1
Abstract:
Heat exchanger (20) for plants for drying bulk agricultural products; the heat exchanger (20) comprising a combustion chamber (23) with a first end (24) suitable to be engaged by a fuel burner (18), wherein the combustion of fuel substantially occurs inside the combustion chamber (23); the heat exchanger (20) including at least one hollow tubular element (40) arranged outside the combustion chamber (23), wherein the heat exchanger (20) comprises a first collector (21) applied to the second end (25) of the combustion chamber (23) opposite to the first end (24), and wherein the collector (21) comprises deviation means that can be alternatively switched between a first position and a second position, so as to convey the hot flue gases, resulting from the combustion of the fuel, from the inside of the combustion chamber (23) to the at least one hollow tubular element (40) and from the combustion chamber (23) to the outside of the heat exchanger (20), respectively.

Inventors:
BARBIERI, Roberto (Via Dosso 52/E, Campodarsego, 35010, IT)
Application Number:
IB2018/053405
Publication Date:
November 22, 2018
Filing Date:
May 16, 2018
Export Citation:
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Assignee:
AGREX SPA (Via Balla, 55/57, Villafranca Padovana, 35010, IT)
International Classes:
F28C3/14; F24H3/04; F24H3/08; F24H9/00; F26B9/00; F26B23/02; F28D7/16; F28D21/00; F28F27/02
Foreign References:
FR1389503A1965-02-19
DE4339045A11995-05-18
EP1407206A22004-04-14
EP0190106A21986-08-06
Attorney, Agent or Firm:
RONCUZZI, Davide (Via Antica Zecca 6, Ravenna, 48121, IT)
Download PDF:
Claims:
CLAIMS

1. Heat exchanger (20), in particular for drying plants for drying bulk agricultural products like cereals or the like, said heat exchanger (20) comprising a combustion chamber (23) with a first end (24) suitable to be engaged by a fuel burner (18) so that the combustion of said fuel substantially occurs inside said combustion chamber (23) , said heat exchanger (20) including at least one hollow tubular element (40) arranged outside said combustion chamber (23) , wherein said heat exchanger (20) comprises a first collector (21) applied to the second end (25) of said combustion chamber (23) opposite to said first end (24), and wherein said collector (21) comprises deviation means that can be alternatively switched between a first position and a second position, so as to convey the hot flue gases, resulting from the combustion of said fuel, from the inside of said combustion chamber (23) to said at least one hollow tubular element (40) and from said combustion chamber (23) to the outside of the heat exchanger (20), respectively, characterized by comprising slowing means for slowing the flow of said flue gases along said at least one hollow tubular element (40) .

2. Heat exchanger (20) according to claim 1, characterized in that said first collector (21) comprises at least one first opening (41), through which said combustion chamber (23) is connected to the outside, and at least one second opening (33) , through which said combustion chamber (23) is connected to said at least one hollow tubular element (40), in that the switching of said deviation means to said first position results in said at least one first opening (41) being closed and said at least one second opening (33) being opened, wherein said flue gases are therefore conveyed from said combustion chamber (23) to said at least one hollow tubular element (40), and in that the switching of said deviation means to said second position results in said at least one first opening (41) being opened and said at least one second opening (33) being closed, wherein said flue gases are therefore conveyed from said combustion chamber (23) to the outside of said heat exchanger (20) .

3. Heat exchanger (20) according to claim 2, characterized in that said deviation means can be switched between said first position and said second position through rotation into two opposite directions respectively.

4. Heat exchanger (20) according to any one of claims 1 to 3, characterized by comprising a second collector (22) for collecting flue gases exiting from said at least one hollow tubular element (40) .

5. Heat exchanger (20) according to claim 4, characterized by comprising suction means for sucking said flue gases from the inside of said second collector (22).

6. Heat exchanger (20) according to any one of claims 1 to 5, characterized in that said slowing means are shaped like a spiral and are housed inside said at least one hollow tubular element (40) .

7. Heat exchanger (20) according to any one of claims 1 to 6, characterized in that it comprises a plurality of said hollow tubular elements (40) arranged outside said combustion chamber (23), in that said first collector (21) comprises a plurality of said second openings (33), each of which connects said combustion chamber (23) to one hollow tubular element (40), in that the switching of said deviation means to said first position results in said at least one first opening (41) being closed and each second opening (33) being opened, wherein said flue gases are therefore conveyed from said combustion chamber (23) to each said hollow tubular element (40) , and in that the switching of said deviation means to said second position results in said at least one first opening (41) being opened and each said second opening (33) being closed, wherein said flue gases are therefore conveyed from said combustion chamber (23) to the outside of said heat exchanger (20) . 8. Heat exchanger (20) according to any one of claims 1 to 7, characterized by comprising electro-mechanical and/or hydraulic means for switching said deviation means between said first position and said second position.

9. Heat generator, including a fuel burner (18), characterized in that it comprises a heat exchanger (20) according to any one of claims 1 to 8, and in that said fuel burner (18) engages said first end (24) of said combustion chamber (23) in such a way that the fuel combustion substantially occurs inside said combustion chamber (23) .

10. Heat generator according to claim 9, characterized in that said burner (18) is suitable to burn liquid or gaseous fuel.

11. Plant (100) for drying cereals and/or similar bulk agricultural products, said plant comprising a processing unit including at least one main container (13) for said cereals and/or bulk agricultural products, characterized by comprising a heat generator according to any one of claims 9 or 10, said heat exchanger (20) being at least partially arranged inside said main container (13), so as to allow heat, generated through fuel combustion, to be transmitted to the inside of said main container (13) .

Description:
HEAT EXCHANGER, HEAT GENERATOR AND EQUIPMENT FOR DRYING

BULK PRODUCTS

DESCRIPTION

The present invention relates to the field of drying bulk materials and/or products, especially cereals and/or similar agricultural bulk products. More in particular, the present invention relates to a heat exchanger, a heat generator and an equipment for drying bulk agricultural materials and/or products and/or cereals provided with said heat exchanger and/or heat generator. In more detail, the present invention provides for an innovative solution for transferring the heat resulting from fuel combustion to agricultural materials and/or products and/or cereals that shall be dried.

PRIOR ART

In the farming field, there is often the need of drying agricultural products, in particular cereals, directly on site or immediately after harvest (threshing in case of cereals) . The cereals, for example corn, are often dried on site, immediately after threshing, so as to avoid problems resulting from the storage and/or the transport of cereals with a too high humidity level, non-compatible with storage and/or transport. To this end, both mobile systems, such as dryers that can be towed, and fixed systems are used, the first for drying the products on site and the second for drying the products in the storage areas.

These mobile and fixed systems usually comprise a main hopper or silo that can be loaded from the top, wherein, for example in the case of dryers, the drying occurs while the cereals fall within the hopper or silo. Simpler systems are also known, wherein the cereals are loaded on a grid, usually inclined to facilitate the unloading thereof, and hot air is inserted into the space below the grid that, moving upwards, dries the cereals passing through them. There are substantially two modes for drying cereals, independently of the type of dryers, that can be movable or fixed, with vertical hopper or grid. According to the first mode, usually used for drying "oily" cereals like sunflower and rape seeds, or cereals destined for human diet (for example in the form of wheat, pasta or similar products), the heat generated by a burner is *indirectly" transferred to the cereals, i.e. By using a heat exchanger; Practically, the heat generated by the burner firstly heats a heat exchanger, wherein this heat exchanger is invested by means of an air flow taken from the environment, and the air heated by the heat exchanger is so conveyed as to transfer heat to the cereals. This drying mode is mandatory according to the regulations in force to avoid any contamination of the cereals, for example due to the flue gases.

On the contrary, according to the second drying mode, the heat generated by the burner is "directly"' transferred to the cereals; Practically, the flame generated by the burner is invested by an air flow taken from the environment, and the air heated by the flame is so conveyed as to transfer heat to the cereals. In some cases, according to this drying mode again, the flame is generated or directed near the materials. There is therefore the risk of contamination of the cereals due to the combustion gases; this second mode is therefore admitted only for drying cereals destined for feeding of cattle (for example for producing fodder and feed) . In view of what described above there is therefore the need for the farmers and in general for all the operators in the agricultural field to have available at least two dryers or drying plants, one for drying the cereals according to the first mode and the other one for drying the cereals according to the second mode.

This involves management costs that are not affordable in the current cereal market, recently experiencing a significant fall in prices, that are not likely to increase again in short times.

In fact, the fact of having available at least two dryers involves maintenance costs (for repair in case of fault or the like) , that are nearly double than the costs for managing a single plant. Moreover, also the consumption of fuel (usually diesel or gas) for operating two dryers is greater than that necessary for operating only one dryer. Lastly, the use of two dryers involves logistics problems, for example the need for having storage areas for the cereals and/or areas for moving the transport means and handling the cereals larger than the areas that would be necessary for a single dryer, wherein the management and arrangement of said areas and the connected buildings (silos, warehouses etcetera) results in an increase in both direct costs (purchase of the areas and construction of buildings) and indirect costs (e.g. cleaning the areas and/or buildings) .

DESCRIPTION OF THE PRESENT INVENTION

The main aim of the invention is to overcome the drawbacks of the prior art solutions, in particular of the known equipment for drying bulk products, in particular agricultural bulk products, such as cereals or similar agricultural products. In particular, an object of the invention is to provide a solution that can be switched between two different configurations for drying bulk agricultural products according to the two modes briefly described above.

The present inventions is especially based on the general idea that the drawbacks of the prior art solutions can be effectively overcome or at least minimized by providing for an heat exchanger so configured as alternatively to be or not to be involved in the drying of the products.

Based on what described above, and taking into account the drawbacks of the prior art solutions as well as the object of the invention, the object of the present invention according to a first embodiment is a heat exchanger, in particular for drying plants for drying bulk agricultural products like cereals or the like, the heat exchanger comprising a combustion chamber with a first end suitable to be engaged by a fuel burner so that the combustion of the fuel substantially occurs inside the combustion chamber, the heat exchanger including at least one hollow tubular element arranged outside the combustion chamber, wherein the heat exchanger comprises a first collector applied to the second end of the combustion chamber opposite to the first end, and wherein the collector comprises deviation means that can be alternatively switched between a first position and a second position, so as to convey the hot flue gases, resulting from the combustion of the fuel, from the inside of the combustion chamber to the at least one hollow tubular element and from the combustion chamber to the outside of the heat exchanger, respectively.

According to an embodiment, the first collector comprises at least one first opening, through which the combustion chamber is connected to the outside, and at least one second opening, through which the combustion chamber (23) is connected to the at least one hollow tubular element, wherein the switching of the deviation means to the first position results in the at least one first opening being closed and the at least one second opening being opened, wherein the flue gases are therefore conveyed from the combustion chamber to the at least one hollow tubular element, and wherein the switching of the deviation means to the second position results in the at least one first opening being opened and the at least one second opening being closed, wherein the flue gases are therefore conveyed from the combustion chamber to the outside of the heat exchanger.

According to an embodiment, the deviation means can be switched between the first position and the second position through rotation into two opposite directions respectively.

According to an embodiment, the heat exchanger comprises a second collector for collecting flue gases exiting from the at least one hollow tubular element.

According to an embodiment, suction means are provided for sucking the fuel gases from the inside of the second collector.

According to an embodiment, slowing means are provided for slowing the flow of flue gases along the at least one hollow tubular element.

According to an embodiment, the slowing means are configured like a spiral and are housed inside the at least one hollow tubular element.

According to an embodiment, the heat exchanger comprises a plurality of hollow tubular elements arranged outside the combustion chamber, wherein the first collector comprises a plurality of second openings, each of which connects the combustion chamber to one hollow tubular element (40), wherein the switching of the deviation means to the first position results in the at least one first opening being closed and each second opening being opened, wherein the flue gases are therefore conveyed from the combustion chamber to each hollow tubular element, and wherein the switching of the deviation means to the second position results in the at least one first opening being opened and each second opening being closed, wherein the flue gases are therefore conveyed from the combustion chamber to the outside of the heat exchanger.

According to an embodiment, electro-mechanical and/or hydraulic means are provided for switching the deviation means between the first position and the second position. A further object of the invention is a heat generator including a fuel burner comprising a heat exchanger according to any one of the embodiments described above, wherein the fuel burner engages with the first end of the combustion chamber so that the combustion of the fuel substantially occurs inside the combustion chamber.

According to an embodiment, the burner is suitable to burn liquid or gaseous fuel.

A further object of the invention is a plant for drying cereals and/or similar bulk agricultural products, the plant comprising a processing unit including at least one main container for the cereals and/or bulk agricultural products, wherein the plant comprises a heat generator according to any one of the embodiments of the present invention, the heat exchanger being at least partially arranged inside the main container, so as to allow heat, generated through fuel combustion, to be transmitted to the inside of the main container.

Any further embodiments according to the invention are defined in the claims.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The embodiments of the invention illustrated in the drawing will be described in detail below; however, the present invention is not limited by the embodiments illustrated in the figures and described below. On the contrary, all variants of embodiments, illustrated and represented in the drawing and detailed below, that will be clearly apparent to those skilled in the art from the description above, fall within the scope of the present invention. Moreover, it should be specified that the present invention applies particularly advantageously to the drying of bulk cereals such as wheat, corn, soya, rape or the like, and this is the reason why the invention will be described below with particular reference to the applications thereof in drying cereals of the mentioned type. However, the present invention applies not only to the drying of cereals nor only to drying plants in general; On the contrary, it applies to all the cases where it is necessary and/or adequate to transfer heat alternatively directly and indirectly, i.e. with or without heat exchanger, according to the needs and/or the circumstances.

In the figures:

- figure 1 shows a perspective view, a front view and a longitudinal cross-section of a heat exchanger according to an embodiment of the invention in closing configuration; - figure 2 shows a perspective view, a front view and a longitudinal cross-section of a heat exchanger according to an embodiment of the invention in opening configuration; - figure 3 shows perspective views of components of a heat exchanger according to an embodiment of the invention;

- figure 4 shows perspective views of components of a collector of a heat exchanger according to an embodiment of the invention;

- figure 5 shows a perspective view of a drying equipment according to an embodiment of the invention;

- figure 6 is a perspective view of a detail the equipment of figure 5.

With reference to figures 5 and 6, the drying system 100 illustrated therein comprises a main drying hopper or silo 13, a load vertical auger conveyor 9 provided with an inspection access 10, a load hopper 8, a hydraulic pump 11, a recirculation auger conveyor 12, a mechanical transmission 14, in particular for actuating the auger conveyors, a duct 15 where a heat exchanger 20 is housed (see the description below), wherein the duct 15 extends from a unit 17 where a burner 18 is housed according to what described in detail below, the unit 17 being provided with a control panel 19. The cereals are dried in the main hopper or silo 13 by inserting heat into the main hopper 13 by means of the heat exchanger 20, that is in turn heated by the burner 18. The operation modes of the system 100 can be summarized as follows. The cereals to be dried are discharged on the load auger conveyor 8 (for example from a trailer or a similar transport means or also directly from the combine harvester) and then conveyed to the base of the auger conveyor 9, fro example through a not illustrated worm, and then moved upwards through the auger conveyor 9 and discharged into the hopper or silo 13. The cereals are then dried while they fall in the hopper 13, wherein the drying cycle may comprise, according to the cereal humidity level, several cycles of loading them in and moving them along the hopper. For example, if the cereals exiting from the hopper 13 downwards are still wet, they are conveyed again towards the vertical auger conveyor 9 through the recirculation worm 12 and are then moved upwards again and discharged into the main hopper 13. In order to facilitate the drying of cereals, in the hopper 134 a cage 130 is provided defining a space where the cereals cannot go, wherein, as shown in figure 6, the free end portion 21 of the heat exchanger 20, i.e. The end portion 21 opposite to the unit 17 and therefore to the burner 18, extends inside said space defined by the cage 130.

As already mentioned, the aim of the present invention is to allow drying the cereals according to two alternative drying modes based on the needs and/or circumstances and/or the type of cereals, i.e. both inserting heat directly into the hopper 13, in particular in the space defined by the cage 130, and inserting heat indirectly, i.e. Through the heat exchanger 20.

To this end, as shown for example in figures 1 and 2, the heat exchanger 20 according to the embodiment of the present invention illustrated therein, comprises a substantially cylindrical combustion chamber 23, with an end portion 24 suitable to be engaged by a fuel burner 18, for example, although without limitation, a diesel burner, so that, as shown, the flames generated by the combustion propagate inside the combustion chamber 23. As shown, the heat exchanger 20 comprises a plurality of hollow tubular elements 40 arranged outside the combustion chamber 23 and parallel thereto, in particular in such a manner and number to substantially cover all the outer surface of the combustion chamber 23, wherein the symmetry longitudinal axis of each hoi low tubular element 40 is substantially parallel to the symmetry longitudinal axis of the combustion chamber 23. In the present description, both the number and the diameter of the hollow tubular elements 40 can be chosen according to the needs and/or circumstances, and also the material of which the hollow tubular elements are made can be chosen, according to the needs and/or circumstances, among suitable metals such as steel or the like.

A substantially cylindrical collector 21 is applied on the end portion 25 of the combustion chamber 23 opposite to the end portion 24, the collector being suitable to be so switched as to convey the hot flue gases (represented by the arrows) , resulting from the combustion of the fuel, alternatively to the inside of the hollow tubular elements 40 and therefore according to a propagation direction inside the chamber 23, or directly outside. To this end, the collector 21 comprises a first flange 32 shaped like a ring gear with inner diameter substantially equal to the outer diameter of the combustion chamber 23, the flange 32 being provided with a plurality of through holes 33, each of which is engaged by a hollow tubular element 40, so as to connect the collector 21 to the hollow tubular elements 40. The collector 21 is also provided with a second round flange 34 including a blind inner or central portion 34c, from which a peripheral or outer portion extends, that is shaped like e ring gear and includes a plurality of through holes 41. The flanges 32 and 34 are joined by means of an outer cylindrical wall 30, wherein the flanges 32 and 34, in combination with the outer cylindrical wall 30, define therefore a space for collecting the gases exiting from the combustion chamber 23, and this collection space can be alternatively connected to the elements 40 (through the holes 33) and to the outside (through the holes 41) . To this end, as shown, the collector 21 comprises a third flange 35 provided with a switching lever 36 and with a plurality of through holes 37, the third flange 35 being shaped like a ring gear and having dimensions (in particular inner and outer diameter) substantially equal to those of the flange 32 and of the peripheral portion shaped like a ring gear of the flange 34. Practically, the flange 35 touches the flange 34 but outside the collection space defined by the flanges 34 and 32 and by the outer cylindrical wall 30. The flange 35 can be switched by rotation through a rotation axis substantially coinciding with the symmetry longitudinal axis of the combustion chamber 23, in particular between a closing position and an opening position. In the closing position (figure 2) , each of the holes 37 of the flange 35 is arranged in correspondence (over) a hole 41 of the flange 34, wherein with the flange 35 in the opening position the fuel gases exiting the combustion chamber 23 and entering the collector 21 therefore flow out of the collector 21 through the flange 34 as shown in particular in figure 2. On the contrary, when the flange 34 is in closing position (figure 1), the holes 37 of the flange 35 are offset with respect to the holes 41 of the flange 34, wherein therefore the holes 41 are closed by the flange, and wherein therefore the combustion gases exiting the chamber 23 and entering the collector 21 are deviated from the collector 21 into the hollow tubular elements 40.

According to the embodiment illustrated in the attached figures, the collector 21 includes a further flange 31 arranged downstream of the flanges 34 and 35 In the gases propagation direction, and therefore outside the collection space defined by the flanges 32 and 34 and by the cylindrical wall 30. In particular, the flange 31 comprises a tubular portion whose outer diameter is substantially equal to the inner diameter of the switchable flange 35, wherein the flange 35 is inserted on the tubular portion of the flange 31 that therefore acts as a support for the rotation of the flange 35. Furthermore, the flange 31 comprises a round plate whose outer diameter is greater than that of the tubular portion, the round plate thus preventing the switching plate 35 from being released. For extracting the gases from the tubular elements 40 a second collector 22 is provided, that is substantially toroidal and into which the gases exiting from the tubular elements are conveyed, and are then conveyed towards the outside, for example through suction or ventilation means, for example a sucker and/or a fan.

Lastly, it should be noted that the collector 21 comprises a refractory plate 50 arranged upstream of the flange 34 in gas propagation direction, and therefore inside the space defined by the flanges 34 and 32 and by the outer cylindrical wall 30, the plate 50 avoiding the over-heating of the flanges 34 and/or 35 especially in the heating and/or drying mode through direct discharge of the fumes through the holes 37 and 41.

The switching flange 35 can be obviously switched manually by acting on the lever or projection 36 or, alternatively, through mechanical and/or electro-mechanical means, not shown in the figures, and according to substantially known modes, not described in greater detail for the sake of conciseness . As it is clearly apparent and proved from the description above of the embodiments shown in the figures, the present invention allows to achieve the above mentioned objects and/or purposes.

In particular, the present invention provides for a solution that can be switched between two different configurations for drying bulk agricultural products according to the alternative drying modes of the prior art. In detail, the heat exchanger according to the invention allows to transfer heat both through direct discharge of the combustion gases and through irradiation by means of the tubular elements, previously heated, as well as through heat irradiation by means of the combustion chamber and of the gases.

Even if the equipment according to the invention has been explained in the above detailed description of the embodiments shown in the drawing, however the present invention is not limited to the embodiments described above and illustrated in the figures.

For example, according to an embodiment, not shown, inside one or more of the hollow tubular elements 40 slowing means can be provided, for example shaped like a spiral, for slowing the flow of gases.

According to a variant, not shown, it is possible to use a burner, for example a burner for solid fuel, such as wood, biomass or the like, suitable to burn the fuel outside the chamber 23, wherein the combustion gases can be conveyed inside the chamber 23 for example by means of a fan or a similar solution, and then deviated according to what described above.

The scope of the present invention is defined by the appended claims.