Cooling Device for Flat Pieces and Method for Cooling Flat Pieces

Abstract

A cooling device for flat pieces and a method including a first cooling element with a first contact surface with the flat piece and a second cooling element with a second contact surface with the flat piece; wherein the first and second cooling element are located facing each other, defining a space between them to introduce the flat piece, and wherein the first cooling element includes a cooling circuit and second cooling element includes another cooling circuit, respectively, distributed evenly along the first and second contact surface with the flat piece through which a continuous flow of liquid coolant circulates. The flat piece is cooled until it reaches the desired temperature in order to then be removed and stored.

Claims

1. A cooling device for flat pieces, comprising: a first cooling element having a first contact surface with a flat piece; a second cooling element having a second contact surface with the flat piece; wherein the first cooling element and second cooling element are located facing each other, defining a space between them to introduce the flat piece, and wherein the first cooling element comprises a cooling circuit distributed along the first contact surface with the flat piece and the second cooling element comprises a cooling circuit distributed along the second contact surface with the flat piece, both circuits being configured for the continuous flow of a coolant fluid.

2. The cooling device of claim 1, further comprising a movement system for moving at least one of the cooling elements with respect to the other in a direction perpendicular to the contact surfaces.

3. The cooling device of claim 1, further comprising a first cooling system to power the cooling circuit of the first cooling element and a second cooling system to power the cooling circuit of the second cooling element.

4. The cooling device of claim 2, further comprising a first cooling system to power the cooling circuit of the first cooling element and a second cooling system to power the cooling circuit of the second cooling element.

5. The cooling device of claim 1, further comprising a single cooling system to power the cooling circuits of the first and second cooling element.

6. The cooling device of claim 2, further comprising a single cooling system to power the cooling circuits of the first and second cooling element.

7. The cooling device of claim 2, wherein the movement system of the cooling elements comprises a plurality of cylinders selected among hydraulic, pneumatic and motorized.

8. The cooling device of claim 1, further comprising an automatic loading and unloading system of the flat pieces coupled to the device.

9. The cooling device of claim 8, wherein the loading and unloading system of the flat pieces is a band of polyethylene terephthalate material coupled to the contact surface of at least one of the cooling elements and motorized wheels.

10. The cooling device of claim 1, wherein the first cooling element and second cooling element each comprise at least one coolant fluid inlet and outlet disposed on surfaces opposite to the contact surfaces of the flat pieces.

11. The cooling device of claim 10, wherein each cooling element comprises a first liquid coolant distributor connected to the coolant fluid inlet and a second coolant fluid distributor connected to the coolant fluid outlet.

12. The cooling device of claim 1, wherein the cooling circuit of the first cooling element and the cooling circuit of the second cooling element comprise a plurality of coils distributed along the contact surface of the flat piece, through which the coolant fluid circulates.

13. The cooling device of claim 1, wherein the first and the second cooling elements are flat and with dimensions that are substantially equal to the dimensions of the flat piece.

14. The cooling device of claim 1, wherein the coolant fluid is water at room temperature.

15. The cooling device of claim 1, further comprising a plurality of first cooling elements and second cooling elements, and wherein each pair of first and second cooling elements are arranged and aligned on the same horizontal plane.

16. The cooling device of claim 1, further comprising a plurality of first cooling elements and second cooling elements arranged horizontally and aligned vertically, wherein all cooling elements face each other, defining a space between each pair of cooling elements to introduce a flat piece, such that the cooling device is configured to simultaneously cool a plurality of flat pieces.

17. The cooling device of claim 1, further comprising a plurality of first cooling elements and second cooling elements arranged vertically and aligned horizontally, wherein all cooling elements face each other, defining a space between each pair of cooling elements to introduce a flat piece, such that the cooling device is configured to simultaneously cool a plurality of flat pieces.

18. A method for cooling flat pieces, comprising: a) providing a cooling device having: a first cooling element having a first contact surface with a flat piece; a second cooling element having a second contact surface with the flat piece; wherein the first cooling element and second cooling element are located facing each other, defining a space between them to introduce the flat piece, and wherein the first cooling element comprises a cooling circuit distributed along the first contact surface with the flat piece and the second cooling element comprises a cooling circuit distributed along the second contact surface with the flat piece, both circuits being configured for the continuous flow of a coolant fluid; b) circulating the coolant fluid through the cooling circuit of the first and second cooling element and through the cooling circuit of the second cooling element; c) introducing a flat piece into the space defined between the first cooling element and second cooling element; d) keeping the flat piece in contact with the first contact surface of the first cooling element and with the second contact surface of the second cooling element for a pre-established time; the pre-established time depending on an initial temperature and final temperature of the flat piece, and the temperature of the coolant fluid; e) separating the first cooling element from the second cooling element by a movement system and removing the flat piece from the space defined between the first and second cooling element.

19. The method for cooling flat pieces of claim 18, wherein after introducing the flat piece into the space defined between the first cooling element and the second cooling element, a distance between the first and second cooling element is adjusted by the movement system of the first and second cooling elements so that the first contact surface and second contact surface come in contact with the flat piece.

20. The method for cooling flat pieces of claim 18, wherein the pre-established time during which the flat piece is kept in contact with the first and second contact surface of the first and second cooling element is at least one minute per millimeter of thickness of the flat pieces, when the coolant fluid is water at room temperature.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0040] As a complement to the description provided herein, and for the purpose of helping to make the characteristics of the invention more readily understandable, a set of drawings is attached as an integral part of said description, which, by way of illustration and not limitation represent the following:

[0041] FIG. 1 is a perspective view of the first exemplary embodiment of the cooling device for flat pieces, wherein the pair of cooling elements are arranged horizontally.

[0042] FIG. 2 is a front view of the cooling device of FIG. 1.

[0043] FIG. 3 is a side view of the cooling device of FIG. 1.

[0044] FIG. 4 is an upper plan view of the cooling device of FIG. 1.

[0045] FIG. 5 is a detail view of the cooling circuit of one of the cooling plates of the device shown in FIGS. 1-4, 7 and 8.

[0046] FIG. 6 is a perspective view of an exemplary embodiment of a vertical cooling device made up of a plurality of cooling elements arranged horizontally and aligned vertically, which is configured to simultaneously cool up to nine flat boards.

[0047] FIG. 7 is a perspective view of another exemplary embodiment of the cooling device for flat pieces, equivalent to that of the preceding figure, but in this case, the cooling elements are arranged vertically, aligned horizontally and configured to simultaneously cool up to four flat boards.

[0048] FIG. 8 is a front view of the cooling device of FIG. 7.

DESCRIPTION OF SEVERAL EXEMPLARY EMBODIMENTS OF THE INVENTION

[0049] A description of several exemplary embodiments of the invention follows, by way of illustration and not limitation, referring to the numbers provided in the figures.

[0050] FIGS. 1-4 show different views of the same exemplary embodiment of the cooling device for flat pieces (16). This particular embodiment is provided for the cooling of a single flat piece (16), for example, a laminated board previously manufactured by means of a hot press, since it only has two cooling elements, such as cooling plates (2, 3) that are arranged parallel to the floor. Specifically, FIG. 1 shows a perspective view of a particular embodiment of the cooling device (1), wherein the board has not been included, and FIG. 2 shows a front view of the same embodiment, wherein the board (16) is shown, cooling; meanwhile, FIGS. 3 and 4 show a side view and an upper plan view, respectively, of this same embodiment.

[0051] The cooling device (1) is mounted on a metal frame (4) that is fixed to the floor. The upper (2) and lower (3) plates of the cooling device (1) are cooled, in this particular case, with water at room temperature. This exemplary embodiment was designed to keep the boards between the two plates (2, 3) during a cooling time of one minute per each mm of board thickness. Nevertheless, other coolants can be used or their temperature can be lowered to lower the cooling times.

[0052] The cooling device (1) has means for moving which comprise eight hydraulic cylinders (5) located on the edges of the upper plate (2) and distributed at equal distances and corresponding to the feet of the frame (4). These hydraulic cylinders (5) are configured to move the upper plate (2) vertically with respect to the lower plate (3), which, in this case, is fixed to the frame (4) by means of brackets (17). In this way, during the process of introducing and removing the board, the hydraulic cylinders (5) increase the separation between both plates (2, 3) by lifting the upper plate (2), and during the cooling stage and with the board inside the existing gap between both plates (2, 3), the cylinders (5) lower the upper plate (2) until it comes in contact with the board. Furthermore, these means for moving can be coupled to the lower plate, keeping the upper plate fixed, or they could move both plates together. Given that the aim of these means for moving is not to press, but rather to simply ensure contact between the piece and the cooling plates, the means for moving are very simple, such that the perfectly horizontal movement of the entire plate is not considered to be critical. Furthermore, the frame (4) has stops (12) to limit the movement of the upper plate (2) carried out by the hydraulic cylinders (5).

[0053] FIGS. 2 and 3 shows the board (16) located in the gap between both plates (2,3), such that the inner surface of the board (16) is supported on the contact surface of the lower plate (3) and the cylinders (5) have been activated to move the upper plate (2) until its contact surface comes in contact with the upper surface of the board (16). In this exemplary embodiment, the design of both plates (2, 3) is identical and it adjusts to the dimensions of the board, since it aims to provide equal and even cooling to both faces of the board, although, depending on the nature of the piece to be cooled, plates with different shapes and sizes could be used such that they cool different surfaces of the piece at different rates or do so partially.

[0054] The plates (2, 3) have inlets (6) and outlets (7) for water on the face opposite to the contact face of the board (16). Connected to each inlet (6) and outlet (7) is a cold-water inlet distributor (8) and another for the hot-water outlet (9). The cold-water inlet distributor (8) connects six cold-water inlet points to the plate via first connecting tubes (10). Likewise, the hot-water outlet distributor (9) connects six hot-water outlet points to the plate via second connecting tubes (11). FIGS. 1-4 do not show the connecting ducts between the cooler (15) and the inlets (6) and outlets (7) of the device (1).

[0055] Regarding the design of the cooling circuits of each of the plates (2, 3) in this particular embodiment, the circuits are made up of coils (20) that distribute the cold water introduced through the cold-water inlets (21) and distributed through perpendicular channels (23) that distribute cold water, which are connected to the coils (20). The coils (20) homogeneously distribute the water along the entire surface of the plate from one of the sides, the reheated water being collected by hot-water reception channels (24) located on the opposite side, and ultimately being removed by the hot-water outlets (22), as shown in FIG. 5. In this way, the temperature of the plate is as homogeneous as possible so that cooling is also homogeneous. The plate is designed so that the same water flow passes through each cooling circuit and cools homogeneously. The separation and diameter of the holes of the channels (23, 24) and coils (20) are calculated to provide the largest exchange surface possible and to facilitate cooling. Other distributions are perfectly viable, provided that the distribution of the coolant fluid is homogeneous along the contact surface of the plates.

[0056] The cooling device (1) also has a board loading and unloading system. In this embodiment, the selected system is a loading system by means of a lower band made of Mylar® (13) driven by a motor (14) coupled to the lower plate (3). Nevertheless, other loading and unloading systems can be used, such as conveyor carriages with suction cups, etc. The use of loading systems with a lower band made of Mylar® has the advantage of having a reduced cost. Another advantage of the loading and unloading system with the Mylar® band is that the unloading of the board, as well as the loading of the following board, can be carried out simultaneously.

[0057] FIG. 6 shows an exemplary embodiment of the cooling device made up of a plurality of cooling plates that is configured to simultaneously cool up to nine flat boards.

[0058] Thus, there are nine pairs of plates (2, 3) placed in parallel planes, aligned vertically and coupled to the same frame (25). Thus, ten plates, one upper (2), one lower (3) and eight intermediate, are used, which act as a first cooling element (2), with respect to the cooling element located directly below it, and as a second cooling element with respect to the cooling element located directly above it. In this case, to optimize the space, instead of hydraulic cylinders, there is a motorized lifting system to move the plates (2, 3) vertically. Furthermore, it has a single cold-water inlet distributor (26) and another for the hot-water outlet (27). The cold-water inlet distributor (26) connects to several points on the cold-water inlet of all plates (2, 3) via first connecting tubes (not shown). Likewise, the hot-water outlet distributor (27) connects to several points on the hot-water outlet of all plates (2, 3) via second connecting tubes (not shown). In this case, the intermediate plates will cool the boards in contact with both their lower and upper surface.

[0059] FIGS. 7 and 8 show an exemplary embodiment wherein four boards (16) are simultaneously cooled by means of pairs of plates (2, 3) arranged vertically instead of horizontally, as shown in the embodiment in FIGS. 1-4 and 6. The boards (16) are only shown in FIG. 8 and not in 7. In this case, the operation is equivalent to that described, such that it comprises the corresponding cylinders (5), but in this case, they are configured to horizontally move at least one of the plates (2, 3).

[0060] FIG. 8 shows the boards (16) located in the gap between the plates (2, 3) in the position in which they are being cooled.

[0061] In this case, the plates (2, 3) also comprise inlets (6) and outlets (7) of water or any other coolant, as well as a cold-water inlet distributor (8) and another for the hot-water outlet (9), and likewise, the cold-water inlet distributor (8) connects six cold-water inlet points to the plate via first connecting tubes (10). Likewise, the hot-water outlet distributor (9) connects six hot-water outlet points to the plate via second connecting tubes (11).

[0062] Likewise, the cooling circuits of each of the plates (2, 3) further comprise coils (20) for the distribution of cold water that is introduced into the cold-water inlets (21) and is distributed by perpendicular channels (23) for the distribution of cold water, which are connected to the coils (20). The coils (20) homogeneously distribute the water along the entire surface of the plate from one of the sides, the reheated water being collected by the hot-water reception channels (24) located on the opposite side and ultimately being removed by the hot-water outlets (22), as shown in FIG. 5.

[0063] In this embodiment, it is also provided that a board loading and unloading system can be incorporated, but in this case, by means of motorized wheels (18) to carry out vertical loading, instead of using motors (14) as carried out in the preceding embodiment in FIGS. 1-4 and 6.

[0064] Regarding the cooling process of the boards, firstly and before introducing the boards, the water flow at room temperature is circulated through the plates until they reach the temperature of the water (or any other coolant fluid). Once the plates are at room temperature, the boards can then be introduced between each pair of plates and the cooling process can begin. The cooling system, which constantly re-circulates the water, is designed to instantly dissipate the heat coming from the board, such that the temperature of the water and the board always remain constant. In this way, the reheated water coming from the cooling device is led to the external cooler (15) that lowers its temperature to room temperature and stores it in a tank. The system reinjects by means of a pump the already cooled water from the tank to the device. Even when the cooling device is open (separated plates) and awaiting the insertion of a piece, the pump of the cooling system will continue to introduce cooled water so that the temperature of the plate remains constant at the value desired and it is not affected by variations in room temperature.

[0065] The permanence time of a board between the cooling plates is calculated with heat conduction equations.

[00001]$k\left(\frac{{\partial }^2.Math.T}{\partial x^2}+\frac{{\partial }^2.Math.T}{\partial y^2}+\frac{{\partial }^2.Math.T}{\partial z^2}\right)+{q^{\prime }}_G^{″}=\rho .Math..Math.c.Math.\frac{\partial T}{\partial t}$

Where:

[0066] k: Thermal conductivity [0067] c: Specific heat capacity [0068] p: Mass density of the material [0069] q.sub.G′″: Energy generated per volume unit [0070] T: Temperature [0071] t: Time [0072] x, y, z: Dimensions

[0073] These equations are not linear, in other words, there is no thickness-permanence time factor. Nevertheless, in the case of boards manufactured via hot-pressing processes, it has been found that with a permanence time equal to the pressing time, in other words, one minute per millimeter of thickness, the boards are sufficiently cooled.

[0074] In a specific embodiment, the aim is to cool a 20-mm-thick laminated board, manufactured by means of a heating process, such that afterwards, the board is at 200° C. and therefore will stay in the cooling device for 20 minutes. The process is provided to progressively cool a wooden board that is in direct contact with steel sheets (contact surfaces of the plates), the core of which has a constant temperature (35° C. to prevent condensation due to the surrounding air humidity). After 20 minutes, the board will leave the cooling device at a temperature that will oscillate between 35° C. and 50° C.

[0075] At the beginning of the process, the greater the temperature difference between the board and the plate, the greater the power dissipated and the greater the power that must be supplied to the plate. In this specific embodiment, the board has a surface area of 10 m.sup.2, such that it needs a maximum of 12000 W/m.sup.2 and it would be necessary to have external coolers with a capacity of: 12000×10×2 (upper face and lower face of the board)=240 kW. Nevertheless, all this power will only be used during a very short period of time (specifically, the first minutes of the cooling process, since as the temperature of the board decreases, the amount of power needed decreases), while it will not be necessary for the rest of the time.

[0076] To avoid having to significantly oversize the external cooler, an accumulation facility is designed, such that:

[0077] The average power of the process is 3300 W/m.sup.2. In other words: 3300×10×2=66 kW. An external cooler with said power is installed. The first seven minutes of the process require more than 3300 W/m.sup.2 and the following twelve minutes need less power since the temperature of the board will gradually decrease. A 10,000-liter collection tank that is capable of storing water at 35° C., which is necessary during the first seven minutes, is installed. During the following twelve minutes, since less power is needed than what is available, the external cooler is in charge of restoring the temperature of the tank to 35° C. for the following cycle.