Dryer

Abstract

To improve the thermal efficiency of the dryer. [Solution] The dryer 1A includes a drying chamber 2, an air heating chamber 3, and a circulation fan 10 that generates circulating air K between the drying chamber 2 and the air heating chamber 3. The heat exchanger 7 is located in the air heating chamber 3 and includes a plurality of heat exchange pipes 7d through which heated gas passes. Each heat exchange pipe 7d heats the circulating air K by heat exchange. Each heat exchange pipe 7d is located in a first area E1 and a second area E2, which are located continuously from the downstream side, and the proportion occupied by one or more heat exchange pipes 7d in the first area E1 is set to be greater than the proportion occupied by one or more heat exchange pipes 7d in the second area E2.

Description

Technical Field

[0001] The present invention relates to a dryer that can efficiently dry tobacco leaves or the like using combustion gas generated in a combustion chamber, for example.

Background Art

[0002] In recent years, with the progress of global warming, it has been desired to further reduce the consumption of fossil fuels, and it has been desired to improve the thermal efficiency when using a dryer. As a system having a configuration related to the present invention, the applicant of the present invention has previously filed an invention disclosed in Patent Document 1 and obtained the rights.

[0003] Patent Document 1 discloses an invention related to a temperature control system in a space for controlling the temperature in a controlled space such as a room to a desired state using a combustion facility that obtains thermal energy by burning solid fuel such as firewood under the name of "temperature control system in a space". The spatial temperature control system disclosed in Patent Document 1 comprises a space to be controlled, a combustion device that indirectly heats at least a portion of the air in the space, a ventilator that circulates air between the space and the combustion device, a solid fuel supply device that supplies solid fuel to the combustion device, and a control unit equipped with a timer. The space is equipped with a first temperature detection unit that detects its temperature and generates spatial temperature data. The combustion device comprises a combustion chamber, a heat exchanger that exchanges heat between hot air generated in the combustion chamber and air supplied from the space through the ventilator, and an exhaust tower that discharges the exhaust gas that has undergone heat exchange in the heat exchanger to the outside. The combustion chamber is equipped with a burner that ignites the solid fuel and functions as an auxiliary combustion device, and an intake fan that takes in air from the outside and supplies it into the combustion chamber. The control unit comprises a second temperature detection unit that detects the temperature of the air and generates exhaust temperature data, and an exhaust fan that forcibly discharges the exhaust to the outside. The control unit reads the ambient temperature data from the first temperature detection unit and, if the ambient temperature falls below a predetermined upper limit of the medium temperature range (hereinafter referred to as condition 1), it transmits a control signal to operate the intake fan and the exhaust fan at a speed faster than a desired speed and activates the timer. The control unit reads the ambient temperature data from the first temperature detection unit and the exhaust temperature data from the second temperature detection unit and, if the ambient temperature exceeds the upper limit of the medium temperature range or the exhaust temperature exceeds a predetermined solid fuel input reference temperature within a predetermined desired time (hereinafter referred to as condition 2), it deactivates the timer and makes a judgment regarding condition 1. If condition 2 is not met, it transmits a control signal (hereinafter referred to as control signal 1) to supply a predetermined desired amount of solid fuel to the solid fuel supply equipment. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2015-4487 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Although the invention disclosed in Patent Document 1 can efficiently maintain the temperature inside the space (drying chamber) within a desired temperature range, there was a need for the development of a dryer with even better thermal efficiency.

[0006] This invention has been made to address the aforementioned conventional circumstances, and its purpose is to provide a dryer with even better thermal efficiency. [Means for solving the problem]

[0007] The first invention for solving the above problems is a dryer comprising a drying chamber in which the material to be dried is contained, an air heating chamber equipped with a heat exchanger, and a circulation fan that generates circulating air between the drying chamber and the air heating chamber, wherein the dryer is configured to dry the material to be dried by passing the circulating air heated by the heat exchanger through the drying chamber, wherein the heat exchanger comprises a plurality of linear and co-sequentially extending heat exchange pipes arranged to intersect the flow path of the circulating air and passing a heated gas as a heat transfer medium through the heat exchanger to heat the circulating air, wherein one or more heat exchange pipes are arranged in each of the first area and the second area which are located continuously from the downstream side in the flow path of the circulating air, and the proportion occupied by one or more heat exchange pipes in the first area is set to be greater than the proportion occupied by one or more heat exchange pipes in the second area.

[0008] In the heat exchanger of the first invention with the above configuration, in the direction of the flow path of the circulating air, the first area closer to the inlet of the drying chamber has a larger contact area between the heat exchange pipe and the circulating air, and the surface temperature of the heat exchange pipe is also higher in the first area compared to the second area. As a result, the circulating air moving closer to the inlet of the drying chamber in the heat exchanger can be heated more efficiently.

[0009] The second invention is the same as the first invention described above, characterized in that a plurality of heat exchange pipes are arranged in the first area, and the plurality of heat exchange pipes located in the first area and one or more heat exchange pipes located in the second area are arranged alternately in a staggered pattern.

[0010] In the second invention with the above configuration, when viewing the heat exchange pipes from the direction of the circulating air flow path, compared to the case where multiple heat exchange pipes are arranged so as to overlap, that is, compared to the case where the heat exchange pipes are not arranged in a staggered pattern, heat exchange between the heat exchange pipes and the circulating air can be promoted as the circulating air moves through the first area and the second area in that order. Therefore, according to the second invention, the heating effect of the circulating air supplied to the drying chamber can be further enhanced compared to the first invention.

[0011] The third invention is the first invention described above, characterized in that the circulating air passage comprises a first passage that passes through first and second areas in the air heating chamber, and a second passage that proceeds from a position immediately after passing through the first and second areas in the first passage toward the drying chamber, and the first passage and the second passage are continuous in an L-shape.

[0012] In the third invention of the above configuration, as the circulating air moves from the first flow path to the second flow path, the flow velocity of the circulating air is reduced immediately before the second flow path. As a result, the heating effect of the circulating air passing through the heat exchanger is further enhanced.

[0013] The fourth invention is any of the first to third inventions described above, wherein the heat exchanger includes an exhaust duct for exhausting the heated gas that has passed inside each heat exchange pipe, and the exhaust duct is located upstream of the second area of ​​the air heating chamber and is arranged to pass through the third area where the upstream side of the first flow path passing through the first and second areas is located.

[0014] In the fourth invention of the above configuration, in the third area, the circulating air can be heated by the heat of the heated gas flowing through the exhaust duct. Furthermore, by further heating the circulating air heated in the third area in the second area, the heating effect of the circulating air can be further enhanced.

[0015] The fifth invention is the fourth invention described above, characterized in that the circulation fan is positioned between the second area and the third area and is configured to draw in outside air flowing into the third area through an outside air inlet or circulating air flowing in from a drying chamber and blow it to the second area, and the exhaust duct is positioned to intersect with the first flow path in the third area.

[0016] In the fifth invention of the above configuration, the heating effect of the outside air flowing into the third area from the outside air inlet, or the circulating air returning to the third area from the drying chamber, can be further enhanced.

[0017] The sixth invention is the fifth invention described above, characterized in that the exhaust duct extends across the air heating chamber side at the outside air inlet.

[0018] In the sixth invention of the above configuration, the outside air flowing into the third area through the outside air inlet can be efficiently heated by heat exchange on the surface of the exhaust duct. In this case, even when a portion of the circulating air is ventilated, the reduction in the heating effect of the circulating air in the first and second areas of the heat exchanger can be minimized.

[0019] The seventh invention is the fourth invention described above, characterized in that the drying chamber and the air heating chamber are arranged side by side in the horizontal direction, and the first, second, and third areas are arranged side by side in the vertical direction from bottom to top.

[0020] In the seventh invention of the above configuration, it becomes easier to reduce the planar size of the air heating chamber. As a result, it becomes easier to miniaturize the dryer itself. [Effects of the Invention]

[0021] According to each of the first to sixth inventions as described above, it is possible to provide a dryer with excellent thermal efficiency during use, and moreover, it is not necessary to newly add any equipment for this purpose. Therefore, it is possible to provide a high-performance heat exchanger at a low cost.

[0022] According to the seventh invention, the planar size of the dryer can be reduced. Therefore, it is possible to provide a high-performance and compact dryer.

Brief Description of the Drawings

[0023] [Figure 1] It is a vertical cross-sectional view of the dryer according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along the line X1-X1 in FIG. 1. [Figure 3] ⏐ It is a cross-sectional view taken along the line Y1-Y1 in FIG. 2. ⏐ ⏐ [Figure 4] ⏐ It is a vertical cross-sectional view of the dryer according to a modified example of the present embodiment. ⏐ ⏐ [Figure 5] ⏐ It is a cross-sectional view taken along the line X2-X2 in FIG. 4. ⏐ [[ID=2)] ⏐ [Figure 6] ⏐ It is a vertical cross-sectional view of the dryer according to the comparison machine. ⏐ ⏐ [Figure 7] ⏐ It is a cross-sectional view taken along the line X3-X3 in FIG. 6. ⏐⏐ ⏐⏐ [Figure 8] ⏐⏐ It is a graph showing the change over time of the temperature in each drying chamber of the invention machine and the comparison machine, and the change over time of the exhaust temperature at the exhaust port of the exhaust duct of each dryer. ⏐⏐ ⏐⏐ ⏐⏐

Modes for Carrying Out the Invention

[0024] ⏐⏐ ⏐⏐ The dryer according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 8. Note that the following description of the preferred embodiment is merely illustrative in nature. ⏐⏐ ⏐⏐

[0025] ⏐⏐ ⏐⏐ [1; About the basic configuration of the present invention] ⏐⏐ ⏐⏐ The basic configuration of the dryer according to an embodiment of the present invention (hereinafter referred to as the present embodiment) will be described with reference to FIGS. 1 and 2. ⏐⏐ ⏐⏐ (注:原文中部分连续的空行在翻译中保留了格式上的对应,以符合行数要求。对于一些重复的格式标记如 [Figure 2] 等按原样保留。)As shown in Figure 1, the dryer 1A according to this embodiment comprises a drying chamber 2 for containing tobacco leaves H (material to be dried), an air heating chamber 3 arranged side by side next to the drying chamber 2, and a concrete foundation 24 that supports the drying chamber 2 and the air heating chamber 3, and has a ventilation passage 23 recessed to open upwards. The ventilation passage 23 is formed continuously from the area below the drying chamber 2 to the area below the air heating chamber 3.

[0026] Drying room 2 is a space enclosed by, for example, exterior wall member 19b and ceiling member 20b, which are building materials that have sufficient thermal insulation properties. Multiple openings 18 are formed at desired locations on the floor 17 of the drying chamber 2, penetrating the thickness direction of the building materials constituting the floor 17 and communicating with the ventilation passage 23. Furthermore, an exhaust port 15 is formed approximately in the center of the ceiling member 20b that constitutes the ceiling of the drying chamber 2, and a damper 15a is placed inside the exhaust port 15 to open and close the opening area of ​​the exhaust port 15.

[0027] The air heating chamber 3 is a space enclosed by, for example, an exterior wall member 19a, a ceiling member 20a, and an interior wall member 21, which are building materials having sufficient thermal insulation properties. The drying chamber 2 and the air heating chamber 3 are separated by the interior wall member 21, which extends vertically. A circulation port 14 is formed near the ceiling of the interior wall member 21, penetrating the thickness direction of the interior wall member 21, and the drying chamber 2 and the air heating chamber 3 are in communication through this circulation port 14.

[0028] An outside air inlet 16 is formed in the ceiling of the air heating chamber 3, penetrating in the thickness direction, and a flap 16a that rotates vertically is attached to the periphery of the opening of this outside air inlet 16. When the flap 16a rotates upward, the outside air inlet 16 is closed, and when it rotates downward, the outside air inlet 16 is opened.

[0029] Furthermore, the lower part of the air heating chamber 3 and the ventilation passage 23 are connected via the air supply port 13, and a support beam 11 is placed between the upper edge of the concrete foundation 24 and the lower edge of the inner wall member 21. In other words, the air supply port 13 is located at the lower surface of the support beam 11 in the air heating chamber 3. The vertical height of the support beam 11 is approximately the same as the position of the floor 17 of the drying chamber 2, which is installed alongside the air heating chamber 3.

[0030] A partition wall 9 is provided in the middle of the air heating chamber 3, dividing it vertically, and a ventilation opening 9a is formed in the partition wall 9 that penetrates vertically. In the air heating chamber 3, the lower side of the partition wall 9 is set as the main heat exchange area 3a, while the upper side is set as the auxiliary heat exchange area 3b. In other words, the air heating chamber 3 has the main heat exchange area 3a and the auxiliary heat exchange area 3b in order, starting from the side where the concrete foundation 24 is located and moving vertically upward.

[0031] The main heat exchange area 3a comprises a furnace body 5 and a heat exchanger 7 installed vertically above the furnace body 5. A burner 4 is connected to the heat exchanger 7, which generates a flame toward the inside of the furnace body 5. On the other hand, the auxiliary heat exchange area 3b comprises a circulation fan 10 whose rotation axis is oriented vertically. The circulation fan 10 is mounted on the partition wall 9 such that its air outlet coincides with the vent 9a.

[0032] The circulation fan 10 is configured to circulate circulating air K between the drying chamber 2 and the air heating chamber 3. Specifically, when the circulation fan 10 is activated, the circulating air K moves downward through the air heating chamber 3, through the supply port 13 which coincides with the lower surface position of the support beam 11, into the ventilation passage 23, then moves to the drying chamber 2 through a plurality of openings 18, rises towards the ceiling side of the drying chamber 2, and then returns to the air heating chamber 3 through the circulation port 14.

[0033] In other words, in the dryer 1A according to this embodiment, the flow path of the circulating air K is composed of a first flow path K1 that passes through the first area E1 and the second area E2 in the air heating chamber 3, a second flow path K2 that is a flow path for the circulating air K within the ventilation passage 23 and is located immediately after passing through the first area E1 and the second area E2 in the first flow path K1 toward the drying chamber 2, and a third flow path K3 that passes through the drying chamber 2 toward the ceiling member 20b from the floor 17 and extends toward the air heating chamber 3. In the dryer 1A, as shown in Figure 1, the first flow path K1 and the second flow path K2 are continuous and extend in an L-shape.

[0034] The burner 4 is surrounded by the outer wall member 19c, the ceiling member 20c, and the floor member 22, and is located in a separate space adjacent to the air heating chamber 3, and is configured to radiate flames into the furnace body 5.

[0035] The furnace body 5 consists of a cylindrical body made of heat-resistant stainless steel, and is supported by support legs 12 on the upper side of the concrete foundation 24 of the main heat exchange area 3a, with its centerline positioned approximately horizontal. The furnace body 5 has its end on the side where the burner 4 is not attached closed, and the lower end of the connecting pipe 6, which is a stainless steel cylindrical body, is connected to the upper part of that end.

[0036] The heat exchanger 7 comprises a first housing portion 7P having a substantially box shape with an inclined upper surface formed by bending a stainless steel plate, a second housing portion 7Q having a substantially rectangular parallelepiped shape located spaced apart from the first housing portion 7P along the centerline direction of the furnace body portion 5, and a plurality of heat exchange pipes 7d, which are hollow stainless steel tubes, arranged between the first housing portion 7P and the second housing portion 7Q, with each heat exchange pipe 7d having a linear shape and extending horizontally in the same direction.

[0037] The first housing section 7P is located on the closed side of the furnace body section 5, while the second housing section 7Q is located on the burner 4 side. Therefore, each heat exchange pipe 7d extends along the centerline of the furnace body section 5.

[0038] In this embodiment, the area downstream of the circulating air K in the flow direction of the heat exchanger 7 is designated as the first area E1, while the area upstream of the first area E1 is designated as the second area E2, thus distinguishing between the two.

[0039] As shown in Figure 1, each heat exchange pipe 7d has a uniformly uniform opening diameter. Furthermore, the number of heat exchange pipes 7d installed in the first area E1 is set to exceed the number of heat exchange pipes 7d installed in the second area E2.

[0040] More specifically, the number of heat exchange pipes 7d installed in the first area E1 is set to 5, and the number of heat exchange pipes 7d installed in the second area E2 is set to 4. In other words, in the heat exchanger 7 of this embodiment, the proportion occupied by all heat exchange pipes 7d located in the first area E1 is set to be greater than the proportion occupied by all heat exchange pipes 7d located in the second area E2.

[0041] In addition, as shown in Figure 1, the heat exchange pipes 7d located in the first area E1 and the heat exchange pipes 7d located in the second area E2 are arranged alternately in a staggered pattern.

[0042] The interior of the first housing section 7P is divided into an inlet section 7a located at the bottom and an outlet section 7c located at the top by a plate arranged almost horizontally. One end of each heat exchange pipe 7d located in the first area E1 is connected to the inlet section 7a, while one end of each heat exchange pipe 7d located in the second area E2 is connected to the outlet section 7c.

[0043] On the other hand, the interior of the second enclosure section 7Q is not partitioned like the first enclosure section 7P, and the other ends of all heat exchange pipes 7d located in the first area E1 and the second area E2 are connected.

[0044] The upper end of the connecting pipe 6 is connected to the vertically lower side of the first housing section 7P, and the heated gas generated in the furnace section 5 flows into the inlet 7a of the first housing section 7P via the connecting pipe 6. The heated gas that flows into the inlet 7a passes through each heat exchange pipe 7d in the first area E1, then reverses direction in the second housing section 7Q, passes through each heat exchange pipe 7d in the second area E2, and flows into the outlet 7c of the first housing section 7P. In other words, the interior of the second housing section 7Q functions as a reversal section 7b that changes the flow direction of the heated gas. Furthermore, the lower end of the exhaust duct 8 is connected to the vertically upper side of the outlet section 7c, so that the heated gas that flows into the outlet section 7c after passing through each heat exchange pipe 7d of the second area E2 flows out into the exhaust duct 8 and is also exhausted from the exhaust port.

[0045] The exhaust duct 8 is positioned to pass through the auxiliary heat exchange area 3b (third area). Specifically, as shown in Figure 2, the exhaust duct 8 extends slightly diagonally upward from the outlet 7c of the first housing section 7P, then extends straight upward to penetrate the partition wall 9, then bends horizontally at a 90-degree angle to pass across the intake side of the circulation fan 10 and the air heating chamber 3 side of the outside air inlet 16, then bends upward at a 90-degree angle, and then extends straight upward so that the exhaust port faces the outside of the air heating chamber 3. In other words, the exhaust duct 8 is installed so as to intersect with the first flow path K1 of the circulating air K in the auxiliary heat exchange area 3b of the air heating chamber 3.

[0046] The circulating air K then passes through the heat exchanger 7, exchanges heat with the heated gas passing through each heat exchange pipe 7d, and moves to the drying chamber 2 in a heated state. As it moves upward within the drying chamber 2 by natural convection, it dries the tobacco leaves H.

[0047] [2; Regarding the effects of the present invention] The operation and effects of the dryer 1A according to this embodiment will be explained with reference to Figure 3. In the heat exchanger 7, the temperature of the heated gas passing through the heat exchange pipe 7d located in the first area E1 is higher than the temperature of the heated gas passing through the heat exchange pipe 7d located in the second area E2. In addition, as mentioned above, the area of ​​the heat exchange surface in the first area E1 is larger than the area of ​​the heat exchange surface in the second area E2. Therefore, in the main heat exchange area 3a, the heating effect of the circulating air K in the first area E1, which is closer to the drying chamber 2, is greater than the heating effect of the circulating air K in the second area E2. In other words, in the air heating chamber 3 of the dryer 1A, the circulating air K moving closer to the drying chamber 2 will have a greater heating effect from the heat exchanger 7. In this case, the heating effect of the circulating air K supplied to the drying chamber 2 can be increased compared to the case where the proportion occupied by one or more heat exchange pipes 7d in the first area E1 of the heat exchanger is the same as the proportion occupied by one or more heat exchange pipes 7d in the second area E2 (Effect 1). As a result, we can provide a dryer with superior drying efficiency for tobacco leaves H using circulating air K.

[0048] In dryer 1A, as shown in Figure 3, when the circulating air K that has passed through the second area E2 passes through the first area E1, the flow of the circulating air K is deflected by the staggered arrangement of pipes, and the flow is disturbed, thereby increasing the frequency of contact of the circulating air K with the heat exchange surface of the heat exchange pipe 7d. In other words, in the heat exchanger 7, the flow path of the circulating air K becomes more complex, improving the heat transfer efficiency between the circulating air K and the heat exchange surface. As a result, the heating effect of the circulating air K moving closer to the opening 18 in the floor 17 of the drying chamber 2 is further enhanced. In other words, the above effect 1 can be made even more pronounced (effect 2). As a result, we can provide a dryer that offers even greater drying efficiency for tobacco leaves H using circulating air K.

[0049] In dryer 1A, the temperature of the heated gas inside the furnace body 5 is higher than the temperature of the heated gas passing through the heat exchanger 7. As shown in Figures 1 and 2, in the air heating chamber 3, the circulating air K passes through the second area E2 and the first area E1 of the heat exchanger 7 in that order, then passes around the furnace body 5, and is then supplied to the drying chamber 2. In this case, the circulating air K heated in the heat exchanger 7 is further heated around the furnace body 5 before being supplied to the drying chamber 2. In other words, the above effect 1 or effect 2 can be further enhanced (effect 3). As a result, we can provide a dryer that offers even greater drying efficiency for tobacco leaves H using circulating air K.

[0050] In dryer 1A, the first channel K1 and the second channel K2 are continuous and extend in an L-shape. Therefore, compared to the case where the first channel K1 and the second channel K2 are continuous in a straight line, the flow velocity of the circulating air K downstream of the first channel K1 becomes slower. As a result, the residence time of the circulating air K around the heat exchanger 7 and furnace body 5 is increased, further promoting heat exchange between the surfaces of the heat exchanger 7 and furnace body 5 and the circulating air K. As a result, the effects 1 to 3 described above can be further enhanced (effect 4). Therefore, it is possible to provide a dryer with even better drying efficiency for tobacco leaves H using circulating air K.

[0051] In the dryer 1A, the circulating air K moving within the auxiliary heat exchange area 3b can be heated by contact with the circumferential surface of the exhaust duct 8 located within the auxiliary heat exchange area 3b. As a result, each of the effects 1 through 4 described above can be further enhanced (effect 5). Therefore, it is possible to provide a dryer with significantly superior drying efficiency of tobacco leaves H using circulating air K.

[0052] [3; Details of the present invention] (Regarding the outside air intake) In dryer 1A, when the flap 16a of the outside air inlet 16 is opened, outside air is drawn into the auxiliary heat exchange area 3b from the outside air inlet 16 as the circulation fan 10 operates. In response to this, the pressure inside the drying chamber 2 changes, the damper 15a of the exhaust port 15 opens automatically, and an amount of circulating air K equivalent to the amount of outside air flowing in at the outside air inlet 16 is discharged from the exhaust port 15 to the outside of dryer 1A. This makes it possible to minimize the decrease in drying efficiency by reducing the humidity of the circulating air K in dryer 1A. On the other hand, a decrease in the temperature of the circulating air K flowing through the first channel K1 is unavoidable.

[0053] Therefore, by positioning the exhaust duct 8 so as to cross the air heating chamber 3 side of the outside air inlet 16, the outside air flowing in from the outside air inlet 16 can be brought into contact with the circumferential surface of the exhaust duct 8 for heat exchange, thereby heating the outside air taken into the air heating chamber 3. As a result, the decrease in the temperature of the circulating air K flowing through the first channel K1 can be suppressed as much as possible. In other words, by providing an outside air inlet 16 in the air heating chamber 3, it is possible to minimize the inhibition of each of the above-mentioned effects 1 to 5.

[0054] (Regarding variations of the dryer) A modified example of this embodiment of a dryer will be described with reference to Figures 4 and 5. Here, components common to the dryer 1A according to this embodiment described above are denoted by the same reference numerals and their descriptions are omitted, while the different components are described below. In the modified dryer 1B, as shown in Figures 5 and 6, the exhaust duct 8 located in the auxiliary heat exchange area 3b is arranged to follow the first flow path K1 of the circulating air K without intersecting it.

[0055] In the modified dryer 1B, although some of the above-mentioned effect 5 is reduced, effects 1 to 4 can be exerted without any problems. Therefore, in this case as well, a dryer with excellent drying efficiency of tobacco leaves H by circulating air K can be provided.

[0056] [4; Tests to confirm the effects of the present invention and their results] The tests conducted to confirm the effects of the present invention and their results will be explained with reference to Figures 1, 2, 6 through 8. In this test, the dryer 1A shown in Figures 1 and 2 was used as the test machine according to the present invention, and the dryer 51 shown in Figures 6 and 7 was used as the comparison machine. The comparative dryer 51 will be described with reference to Figures 6 and 7. With respect to dryer 51, components common to dryers 1A and 1B according to the above embodiment will be denoted by the same reference numerals and their descriptions will be omitted, while the different components will be described below.

[0057] In the dryer 51, the form and arrangement of the exhaust duct 8 in the auxiliary heat exchange area 3b of the air heating chamber 3 were made the same as in the modified dryer 1B described above. As shown in Figure 7, the heat exchanger 7' in the dryer 51 is configured such that there are three heat exchange pipes 7d' in both the first area E1 and the second area E2, and the heat exchange pipes 7d' are arranged so that their centerlines, when viewed from the direction of their centerlines, form a grid. In addition, in dryer 51, the diameter of the heat exchange pipe 7d' is set to a value larger than the diameter of the heat exchange pipe 7d in dryer 1A, so that the sum of the surface areas of all the heat exchange pipes 7d in the heat exchanger 7 of dryer 1A is the same as the sum of the surface areas of all the heat exchange pipes 7d' in the heat exchanger 7' of dryer 51. All other configurations for dryer 51 were set to be the same as those for dryer 1A.

[0058] In this test, temperature sensors were installed inside the drying chambers 2 of dryer 1A and dryer 51, as well as at the exhaust port of the exhaust duct 8, and the temperature changes at each location were recorded in one-minute intervals. Dryer 1A and dryer 51 each have a control unit (not shown), and during this test, the control unit controlled the ignition and extinguishing of the burner 4 to maintain the temperature inside the drying chamber 2 at a preset temperature.

[0059] The results of this examination will be explained with reference to Figure 8. In the graph of Figure 8, the upper section shows the change in temperature over time in the drying chambers of the inventive dryer 1A and the comparative dryer 51, while the lower section of the same graph shows the change in exhaust temperature over time in the exhaust ducts 8 of dryer 1A and dryer 51, respectively.

[0060] As shown in the upper part of the graph in Figure 8, when comparing the temperature T1 inside the drying chamber 2 of dryer 51 with the temperature T2 inside the drying chamber 2 of dryer 1A, the temperature T2 inside the drying chamber 2 of dryer 1A was slightly higher. As shown in the lower part of the graph in Figure 8, when comparing the exhaust temperature T3 at the exhaust port of the exhaust duct 8 of dryer 51 with the exhaust temperature T4 at the exhaust duct 8 of dryer 1A, the exhaust temperature T3 at the exhaust duct 8 of dryer 51 was higher. From the above results, it is presumed that dryer 51 discharges more heat than dryer 1A. As a result, it is presumed that the temperature inside the drying chamber 2 of dryer 1A was slightly higher than the temperature inside the drying chamber 2 of dryer 51. In other words, it can be inferred that the air heating chamber 3 of dryer 1A is able to exchange heat from the combustion gas (heated gas) with the circulating air K more efficiently than the air heating chamber 3 of dryer 51.

[0061] As shown in the lower part of the graph in Figure 8, the exhaust temperatures T3 and T4 at the exhaust ports of the exhaust ducts 8 of dryer 1A and dryer 51 both rise and fall in short intervals, with the minimum position corresponding to the ignition timing of burner 4 and the maximum position corresponding to the extinguishing timing of burner 4. In the invented dryer 1A, the time interval between the previous ignition and the next ignition of burner 4 (hereinafter referred to as the ignition interval) was longer compared to the comparative dryer 51. In this test, a control unit (not shown) was used to ignite the burner 4 when the temperature inside the drying chamber 2 reached a preset lower limit, and to extinguish the burner 4 when the temperature inside the drying chamber 2 reached a preset upper limit. Therefore, the longer ignition interval of the burner 4 in dryer 1A compared to dryer 51 means that the rate at which the temperature inside the drying chamber 2 of dryer 1A decreases is slower than that of dryer 51. On the other hand, since the performance of the burner 4 of dryer 1A is the same as that of the burner 4 of dryer 51, the above results indicate that dryer 1A consumes less fuel than dryer 51 to maintain the temperature inside the drying chamber 2 at the desired temperature.

[0062] In this test, it was ultimately confirmed that the combustion efficiency of the burner 4 of the invented dryer 1A was approximately 20% higher than that of the comparative dryer 51. Therefore, this test confirmed that by using the dryer 1A according to this embodiment, it is possible to provide a dryer with excellent thermal efficiency during use.

[0063] In this embodiment, the dryer 1A, by using the heat exchanger 7, can improve the heating effect of the circulating air K supplied to the drying chamber 2 compared to the case where the heat exchanger 7' of the dryer 51 is used. Furthermore, when drying not only tobacco leaves H, but also agricultural and marine products such as shiitake mushrooms and seafood with high moisture content using a dryer 1A, if the moisture content of these agricultural and marine products has not been sufficiently reduced, it is necessary to release a portion of the circulating air K to the outside from the exhaust port 15 to lower the humidity in the circulating air K, while taking in outside air with relatively low humidity from the outside air inlet 16. At that time, a decrease in the temperature of the circulating air K flowing through the first flow path K1 occurs. In this case, by arranging the exhaust duct 8 located in the auxiliary heat exchange area 3b so as to intersect with the first flow path K1 of the circulating air K, or by arranging the exhaust duct 8 so as to cross the air heating chamber 3 side of the outside air inlet 16, it is possible to minimize the decrease in the temperature of the circulating air K flowing through the first flow path K1 when outside air is taken in from the outside air inlet 16.

[0064] On the other hand, once the moisture content of the tobacco leaves H has been sufficiently reduced, there is no need to actively take in outside air from the outside air inlet 16. Therefore, at this stage, even without an exhaust duct 8 in the form shown in Figures 1 and 2, that is, even using the dryer 1B shown in Figures 4 and 5, the heating effect of the circulating air K can be fully realized.

[0065] [5; Others] (Regarding variations of exhaust ducts) Although not specifically shown in the figures, the exhaust ducts 8 of the dryers 1A and 1B according to this embodiment may be equipped with metal heat dissipation fins on their circumferential surfaces. In this case, the heat from the heated gas passing through the exhaust duct 8 via the heat dissipation fins can be exchanged with the circulating air K more efficiently.

[0066] (Regarding other variations of the present invention) In this embodiment of the present invention, a damper 15a is provided at the exhaust port 15 of the drying chamber 2, but providing the damper 15a is not essential. Furthermore, in addition to the damper 15a, the exhaust port 15 may also be equipped with an exhaust fan (not shown) whose rotation axis is oriented vertically.

[0067] Furthermore, in the embodiment of the present invention, five heat exchange pipes 7d are arranged in the first area E1 and four heat exchange pipes 7d are arranged in the second area E2. However, it is sufficient to ensure that the proportion occupied by all the heat exchange pipes 7d located in the first area E1 is greater than the proportion occupied by all the heat exchange pipes 7d located in the second area E2. For example, four heat exchange pipes 7d may be arranged in the first area E1 and three heat exchange pipes 7d in the second area E2, or ten heat exchange pipes 7d may be arranged in the first area E1 and eight heat exchange pipes 7d in the second area E2.

[0068] Furthermore, in the embodiments of the present invention, the furnace body 5 and the heat exchanger 7 are formed using stainless steel, but they may be formed using other metal materials. Furthermore, in the embodiment of the present invention, the heat exchange pipes 7d of the heat exchanger 7 are arranged in a staggered pattern with five heat exchange pipes 7d located in the first area E1 and four heat exchange pipes 7d located in the second area E2. However, the invention is not limited to this configuration. For example, three heat exchange pipes 7d may be arranged in the first area E1 and two heat exchange pipes 7d in the second area E2 to create a staggered arrangement. Alternatively, the arrangement of the heat exchange pipes 7d can be made in a staggered pattern using any other combination of numbers.

[0069] Although the dryers 1A and 1B of the embodiment of the present invention are applied to drying tobacco leaves, they can also be applied to other drying applications, such as drying edible mushrooms like shiitake mushrooms and agricultural and marine products like seafood. [Industrial applicability]

[0070] As described above, the present invention is a dryer that can efficiently dry agricultural and marine products such as tobacco leaves using combustion gas generated in a combustion chamber, and is applicable in the technical fields of drying equipment for agricultural and marine products and heating equipment for rooms. [Explanation of Symbols]

[0071] 1A, 1B…Dryer 2…Drying chamber 3…Air heating chamber 3a…Main heat exchange area 3b…Auxiliary heat exchange area 4…Burner 5…Furnace body 6…Connecting pipe 7, 7'…Heat exchanger 7P…First enclosure 7Q…Second enclosure 7a…Inlet 7b…Return section 7c…Outlet 7d, 7d'…Heat exchange pipe 8…Exhaust duct 9…Partition wall 9a…Ventilation opening 10…Circulation fan 11…Support strut 12…Support leg 13…Supply port 14…Circulation port 15…Exhaust port 15a…Damper 16…Outside air inlet 16a…Flap 17…Floor 18…Opening 19a, 19b, 19c…Exterior wall members 20a, 20b, 20c…Ceiling members 21…Interior wall members 22…Floor members 23...Ventilation channel 24...Concrete foundation 51...Dryer (comparative unit) K...Circulating air K1...First channel K2...Second channel K3...Third channel H...Tobacco leaves (material to be dried)

Claims

1. A dryer comprising: a drying chamber containing the material to be dried; an air heating chamber having a furnace body where heated gas is generated and a heat exchanger connected to the furnace body, and having first to third areas, with an outside air inlet formed in the third area; and a circulation fan positioned between the second and third areas to generate circulating air between the drying chamber and the air heating chamber, wherein the material to be dried is dried by passing the circulating air heated by the heat exchanger through the drying chamber, The heat exchanger comprises a plurality of linear and co-sequentially extending heat exchange pipes arranged to intersect the flow path of the circulating air and through which the heated gas passes to heat the circulating air by heat exchange, and an exhaust duct for exhausting the heated gas that has passed inside each of the heat exchange pipes. The heat exchange pipes are arranged one or more in the first area and the second area, which are located continuously from the downstream side in the flow path of the circulating air. The proportion occupied by one or more heat exchange pipes in the first area is set to be greater than the proportion occupied by one or more heat exchange pipes in the second area. The exhaust duct is located upstream of the second area and passes through the third area where the upstream side of the first flow path passing through the first and second areas is located, and has a region that crosses a flow path in the third area through which outside air introduced from the outside air inlet moves until it is drawn into the suction port of the circulation fan. A dryer characterized in that the heated gas generated in the furnace section moves in the order of the heat exchange pipes arranged in the first area, the heat exchange pipes arranged in the second area, and the exhaust duct.

2. In the dryer according to Claim 1, A dryer characterized in that the outside air inlet and the suction port of the circulation fan are arranged so that at least a portion of their areas face each other.

3. In the dryer according to Claim 2, A circulation port is formed between the drying chamber and the air heating chamber, allowing the circulating air to flow from the drying chamber into the air heating chamber. The dryer is characterized in that the exhaust duct has a region that extends across the air heating chamber side at the circulation port.

4. In the dryer according to any one of Claims 1 to 3, A dryer characterized in that the region located in the third area of ​​the exhaust duct is provided with metal heat dissipation fins on its circumferential surface.

5. In the dryer according to any one of claims 1 to 3, Multiple heat exchange pipes are arranged in the first area. A dryer characterized in that a plurality of heat exchange pipes located in the first area and one or more heat exchange pipes located in the second area are arranged alternately in a staggered pattern.

6. In the dryer according to any one of claims 1 to 3, The circulating air flow path includes a second flow path that proceeds from a position immediately after passing through the first and second areas in the air heating chamber toward the drying chamber, A dryer characterized in that the first channel and the second channel are continuous and extend in an L-shape.

7. In the dryer according to any one of claims 1 to 3, The drying chamber and the air heating chamber are arranged side by side in the horizontal direction. The dryer is characterized in that the first, second, and third areas are arranged in order from bottom to top in the vertical direction.

Images