JP2015215114A - Food drier machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food drier machine of which size can be made small and working efficiency can be improved.SOLUTION: A food drier machine main body 20 blows air sucked through a suction hole of a suction side wall 21A of a drying case 21 under driving of an inner fan 27F and heated by a heater 25 toward the foods to be dried in the first to third food storing chambers 22B to 22D and discharges it through the discharge hole at the discharge side wall 21C. Within the drying case 21 is arranged a casing 28B for connecting an outer peripheral part 28I enclosing the outer periphery of the inner fan 27F with an inner periphery of the drying case 21. An inner space of the drying case 21 is divided into the first to third food storing chambers 22B to 22D with the suction side wall 21A while holding the inner fan 27F between them.

Description

  The technology disclosed in the present application relates to a food dryer that rotates a fan to circulate high-temperature gas in a drying case.

  As a conventional food dryer, for example, in a rectangular parallelepiped drying case extending in one direction, a drying chamber in which the food to be dried is placed is a direction in which the drying case is extended (hereinafter referred to as “lateral direction”). And so-called “horizontal blowing type food dryer” (for example, Patent Document 1). Each of the drying chambers of the food dryer is provided with a plurality of tray mounting shelves that can store trays on which the food to be dried is placed. The food dryer drives the inner fan, heats the air sucked from the air intake holes with a heater, blows air toward the food to be dried in each drying chamber, and exhausts air containing moisture taken from the food to be dried Exhaust from the hole.

JP 2010-203643 A

  By the way, in the above-described food dryer, a plurality of drying chambers (for example, two or three chambers) are provided in the lateral direction, and in order to sufficiently distribute the heated air to all the drying chambers, An inner fan is provided for each. For this reason, an increase in the size of the apparatus has been caused by providing a plurality of inner fans in the drying case. The plurality of inner fans are fixed to a long rotating shaft that is inserted in the drying case in the lateral direction so as to be integrally rotatable so that the driving source is shared and driven in conjunction with each other. For this reason, when the operator puts the food to be dried into and out of the drying chamber, there is a rotating shaft that penetrates the drying chamber in the lateral direction, thereby providing a cart for carrying the food to be dried and an appliance for holding the food to be dried (for example, , Fishing gear for food to be dried) and the like are difficult to put in and out, resulting in a decrease in work efficiency.

  The technology disclosed in the present application has been proposed in view of the above problems. An object of the present invention is to provide a food dryer capable of reducing the size of the apparatus and improving the work efficiency.

  A food dryer according to the technology disclosed in the present application is provided with a drying case having an intake side wall provided with an intake hole and an exhaust side wall provided with an exhaust hole, and provided in the drying case, and is sucked from the intake hole. A heater that heats the gas to be dried, a placement portion that is provided in the drying case and on which the food to be dried is placed, is rotatably held in the drying case, and is sucked from the intake hole and heated by the heater Connect the inner fan that blows air toward the food to be dried in the mounting part and exhausts it from the exhaust hole of the exhaust side wall, the outer peripheral part that surrounds the outer periphery of the inner fan, and the inner peripheral surface of the drying case. And a casing that divides the internal space into a placement portion side and an intake side wall side with an inner fan interposed therebetween.

  Moreover, the food dryer which concerns on the technique disclosed by this application is good also as a structure provided with the wind direction board which guide | induces the flow of the gas to the direction which goes to a mounting part from an inner fan.

  Further, in the food dryer according to the technique disclosed in the present application, the wind direction plate spreads radially in a direction orthogonal to the rotation axis from the fixed portion provided on the axis of the rotation axis of the inner fan. In addition, a configuration may be provided that includes a plurality of blade portions that form a predetermined angle with a plane orthogonal to the rotation axis.

  In the food dryer according to the technique disclosed in the present application, the casing is formed in a box shape surrounding the wind direction plate, and the gas flows in the direction from the inner fan to the mounting portion at the four corners of the inner periphery thereof. It is good also as a structure provided with the stationary blade which guide | induces.

  Moreover, the food dryer which concerns on the technique disclosed by this application is good also as a structure by which the inclination part which inclines as a casing goes to a mounting part from an outer peripheral part is provided.

  Moreover, the food dryer which concerns on the technique disclosed by this application is good also as a structure provided with several mounting parts, and the said several mounting parts are arrange | positioned adjacently.

  Moreover, the food dryer which concerns on the technique disclosed by this application is good also as a structure provided with the external duct which circulates the gas exhausted out of the drying case from the exhaust hole to the inlet hole side.

  In the first aspect of the food dryer of the present application, the inner fan blows the gas sucked from the intake hole and heated by the heater toward the food to be dried of the mounting portion, and discharged from the exhaust hole of the exhaust side wall. To do. The casing connects the outer peripheral portion surrounding the outer periphery of the inner fan and the inner peripheral surface of the drying case, and divides the inner space of the drying case into a placement portion side and an intake side wall side with the inner fan interposed therebetween. Thereby, the direction of the air blown from the inner fan is guided by the outer peripheral portion and the casing, and is efficiently blown toward the mounting portion. Moreover, the gas blown around the inner fan is suppressed by the casing that partitions the internal space of the drying case. Thereby, the inner fan is drawn out as much as possible, and the air volume of the gas blown toward the mounting portion can be increased. Therefore, it is not necessary to provide a fan for each drying chamber in which the placement section in the drying case is divided, and the apparatus can be downsized. In addition, when a plurality of fans are eliminated, a long drive shaft for driving the fans in conjunction with each other is not necessary. Therefore, when the worker puts and removes the food to be dried placed on the placement unit, the work is not hindered by the drive shaft, and the work efficiency can be improved.

  Moreover, in the 2nd side surface of the food dryer of this application, it is prevented that the gas ventilated from an inner fan is guide | induced toward a mounting part by a wind direction board, and it is prevented from staying and the whole mounting part. Therefore, the air is blown uniformly.

  Moreover, in the 3rd side surface of the food dryer of this application, the fixing | fixed part of a wind direction board is provided on the axis line of the rotating shaft of an inner fan. In addition, the blade portion extends radially from the fixed portion in a direction orthogonal to the rotation axis, and forms a predetermined angle with a plane orthogonal to the rotation axis. As a result, the gas blown from the inner fan becomes a stream of air in a cyclonic vortex by a plurality of blades formed at a predetermined angle, and the gases having different humidity and temperature are agitated toward the mounting part. Will be blown. Therefore, according to the food dryer, it is possible to blow a gas having a more uniform temperature difference toward the placement unit. Moreover, it becomes possible to change the aspect of an airflow by adjusting the angle, shape, etc. of a blade | wing part.

  Moreover, in the 4th side surface of the food dryer of this application, a stationary blade is provided in the four corners of the inner peripheral part in the box-shaped casing surrounding a wind direction board. Thereby, for example, the gas blown from the inner fan is restrained from staying and backflowing of the gas by the fixing portion that fixes the blade portion, and is blown extremely uniformly over the entire mounting portion.

  Moreover, in the 5th side surface of the food dryer of this application, the inclination part which inclines as a casing goes to a mounting part from an outer peripheral part is provided. Thereby, since the gas blown from the inner fan flows along the inclination of the inclined portion, it is possible to reduce the possibility of gas stagnation and vortex generation and to further improve the blowing efficiency.

  Moreover, in the 6th side surface of the food dryer of this application, size reduction of an apparatus is attained further, aiming at the improvement of ventilation efficiency by arrange | positioning a several mounting part adjacently.

  In the seventh aspect of the food dryer of the present application, the high-temperature gas exhausted from the exhaust hole to the outside of the drying case of the food dryer passes through the external duct and is sucked into the drying case from the intake hole. The Thereby, since the exhausted high-temperature gas is again sucked into the food dryer, the heat efficiency of heating the gas by the heater is improved, and the consumed fuel efficiency is improved.

It is a simplified perspective view of the food dryer with a duct of this embodiment. It is a sectional side view of a food dryer. It is a simplified perspective view of the food dryer of the state which removed the duct. It is a perspective view which shows a casing. It is a perspective view which shows a wind direction board and a stationary blade. It is a side view of a food dryer with a duct. It is a disassembled perspective view of a food dryer external duct. It is the perspective view which expanded the part which concerns on the damper drive source of an intake cover part, and an intake damper manual handle. It is a perspective view which shows the wind direction board in another food dryer.

  Hereinafter, a food dryer according to an embodiment of the present invention will be described with reference to FIGS. A food dryer 10 according to this embodiment shown in FIG. 1 includes a food dryer main body 20 and a food dryer external duct 40 (hereinafter simply referred to as “external duct 40” fixed to the outer peripheral surface of the food dryer main body 20. "). The food dryer main body 20 is a so-called shiitake dryer for producing food to be dried, for example, dried shiitake mushrooms, and is entirely covered with a drying case 21 made of sheet metal. The drying case 21 has a rectangular parallelepiped shape that is long in one direction parallel to the installation surface on which the food dryer 10 is installed. In the following description, as shown in FIG. 1, the direction perpendicular to the installation surface on which the food dryer main body 20 is installed is the vertical direction, the direction in which the rectangular parallelepiped drying case 21 is extended is the horizontal direction, the vertical direction A direction perpendicular to both the direction and the lateral direction will be referred to as the front-rear direction. The drying case 21 is formed in a rectangular parallelepiped shape whose lateral direction is longer than the vertical direction and the front-rear direction.

  As shown in FIG. 2, the inside of the drying case 21 is divided into a plurality of drying chambers in the lateral direction. The plurality of drying chambers are a heating room 22A, a first food storage room 22B, a second food storage room 22C, and a third food storage room 22D in order from the left side of FIG. The first to third food storage rooms 22B to 22D are arranged adjacent to each other in the lateral direction. A heater 25 is accommodated in the heating chamber 22A. The heater 25 includes, for example, a cylindrical heating drum 25A extending in the front-rear direction of the drying case 21, and a base end connected to the upper surface of the rear side of the heating drum 25A, and meanders from the base end in the front-rear direction. Meandering pipe 25 </ b> B extending upward.

  As shown in FIG. 3, the heating wall burner 23 is fixed to the front wall 21X of the drying case 21 at the lower end of the portion corresponding to the heating chamber 22A. The heating burner 23 is connected to the front end portion of the heating drum 25A through a vent hole 21H (see FIG. 4) in the front wall 21X. Further, the leading end portion of the meandering pipe 25B protrudes outward from the upper end portion of the rear wall 21Y of the drying case 21, and is connected to a chimney 24 formed by bending upward toward the protruding distal end portion. .

  As shown in FIG. 2, a fan drive shaft 27 is provided at an intermediate position in the vertical direction of the drying case 21 so as to penetrate the heating chamber 22 </ b> A in the horizontal direction and is rotatably supported. The fan drive shaft 27 has an inner fan 27F fixed to a tip portion, in other words, a position close to the portion where the first food storage chamber 22B is connected to the heating chamber 22A. The inner fan 27F is fixed to the fan drive shaft 27 so as to be integrally rotatable.

  In the drying case 21, an air blowing assist unit 28 is provided. FIG. 4 is a perspective view of the inner fan 27F and the air blowing auxiliary unit 28 provided in the heating chamber 22A as viewed from the first food storage chamber 22B side, with a wind direction plate 28C and a stationary blade 28D described later removed. Is shown. As shown in FIG. 4, the inner fan 27 </ b> F is formed radially from the outer peripheral surface of a base portion 27 </ b> D in which a plurality (three in the illustrated example) of blades 27 </ b> T are fixed to the fan drive shaft 27. The blade 27T rotates around the rotation axis of the fan drive shaft 27 as the base 27D rotates integrally with the fan drive shaft 27. The blades 27T have a plate shape formed with a predetermined width in the rotation direction, and are inclined at a predetermined angle with respect to a direction orthogonal to the rotation axis. The direction orthogonal to the rotation axis is an arbitrary direction along a plane parallel to the vertical direction and the front-rear direction. Moreover, the outer peripheral part of the wing | blade 27T is formed in circular arc shape along the rotation direction, and the protrusion part 27E which protruded to the one side of the rotation direction is formed.

  The air blowing auxiliary unit 28 includes a casing 28B, a wind direction plate 28C (see FIG. 5), and a stationary blade 28D (see FIG. 5). The casing 28B includes a casing substrate 28E, a side plate 28F, an inclined portion 28G, and a flat plate portion 28H. The casing substrate 28E is formed in a plate shape whose plane is along the front-rear direction and the up-down direction, and an outer peripheral portion 28I in which a circular hole is formed so as to surround the blade 27T of the inner fan 27F is formed at a substantially central portion. . The casing substrate 28E has a pair of side plates 28F connected to both ends in the front-rear direction. FIG. 4 shows only one side plate 28F. The pair of side plates 28F is fixed to the inner peripheral surfaces facing each other in the front-rear direction of the heating chamber 22A.

  The casing substrate 28E has a pair of inclined portions 28G connected to both ends in the vertical direction. The pair of inclined portions 28G are inclined so as to spread outward so that the distance in the vertical direction facing each other becomes longer as they go from the base end portion of the fan drive shaft 27 to the tip end portion. The air blown from the inner fan 27F flows along the inclination of the inclined portion 28G. Each of the pair of inclined portions 28G is connected to a pair of flat plate portions 28H continuously from the end portion on the opposite side to the end portion connected to the casing substrate 28E in the vertical direction. The pair of flat plate portions 28H is formed in a plate shape whose plane is along the horizontal direction and the front-rear direction, and the end portion on the opposite side to the end portion connected to the inclined portion 28G in the horizontal direction is the inner peripheral surface of the heating chamber 22A. Is fixed to a plate 28J extending in the vertical direction. Thereby, the casing 28B connects the outer peripheral portion 28I and the inner peripheral surface of the drying case 21, and the first space to the third food storage chambers 22B to 22D with the inner fan 27F interposed between the inner space of the drying case 21. And the intake side wall 21A side.

  The heating chamber 22A is provided with a C-shaped steel (lip groove steel) 27C disposed along the front-rear direction at the center in the vertical direction, which is an opening portion on the first food storage room 22B side. . In the C-shaped steel 27C, both ends in the front-rear direction are fixed to the side plate 28F so that the lip is on the first food storage room 22B side. In the C-shaped steel 27C, a bearing bearing 27B is provided at a central portion in the longitudinal direction of the groove. The fan drive shaft 27 is rotatably held at the tip end thereof with respect to the C-shaped steel 27C via a bearing bearing 27B.

  FIG. 5 is a perspective view of the wind direction plate 28C and the stationary blades 28D provided in the air blowing assist unit 28 as viewed from the first food storage room 22B side. In addition, since drawing becomes complicated, illustration of the inner fan 27F is abbreviate | omitted. The air blowing assisting part 28 is provided with a wind direction plate 28 </ b> C so as to surround the fan drive shaft 27. The wind direction plate 28C includes a fixed portion 29A and a blade portion 29B. The fixed portion 29A is formed in a disc shape along a plane orthogonal to the fan drive shaft 27, and the first food of the C-shaped steel 27C is such that the center position P1 is on the axis of the fan drive shaft 27. It is fixed on the accommodation room 22B side. The fixed portion 29A is provided with a plurality of blade portions 29B formed at equal intervals along the circumferential direction on a circular outer peripheral portion.

  Each of the blade portions 29 </ b> B is formed radially from the fixed portion 29 </ b> A in a direction orthogonal to the rotation axis of the fan drive shaft 27. The blade portion 29B is formed in a rectangular plate shape in which the direction from the base end portion connected to the fixed portion 29A toward the outer peripheral portion is the longitudinal direction. The blade portion 29B forms a predetermined angle with the plane orthogonal to the fan drive shaft 27, in other words, the plane of the fixed portion 29A. For example, the blade portion 29B is fixed while being twisted with respect to the fixing portion 29A at an angle of 45 degrees with respect to the plane of the fixing portion 29A. The blade portion 29B is formed with a connecting portion 29D protruding at one end in the short direction at the distal end portion in the longitudinal direction. The blade portion 29B has a proximal end portion in the longitudinal direction connected to the fixing portion 29A, and a connecting portion 29D at the distal end portion connected to the casing substrate 28E to be fixed in position. Further, the blade portion 29B is formed with a bent portion 29E that is bent toward the casing substrate 28E at the distal end portion in the longitudinal direction. In the blade portion 29B, the direction and amount of air to be blown can be changed according to the angle and size of the bent portion 29E.

  The heated air blown from the inner fan 27F (see FIG. 4) is guided from the fixed portion 29A to a plurality of air passages radially divided by the blade portions 29B, and the first to third food accommodation rooms 22B to 22D. It is blown toward. The air to be blown becomes an airflow wound in a cyclonic vortex by the plurality of blade portions 29B formed by twisting at a predetermined angle, and the first to third food containing rooms are stirred while the air having different temperature and humidity is stirred. The air is sent toward 22B to 22D. Therefore, the airflow mode can be changed by adjusting the angle of the blade portion 29B. Thereby, the heated air will spread uniformly throughout the first to third food accommodation rooms 22B to 22D.

  A plurality (four in this embodiment) of stationary blades 28D are provided on the inner peripheral portion of the casing 28B. Each of the stationary blades 28D is formed at each of the four corners in the inner peripheral portion of the casing 28B formed in a box shape. The stationary blade 28D is a straight line that connects the center position P1 of the fixed portion 29A on the axis of the fan drive shaft 27 and the position P2 that is the connecting portion between the inclined portion 28G and the plate 28J and is the end portion in the front-rear direction. It is formed with a flat plate along. The stationary blade 28D extends from the position P2 toward the center position P1, and is formed up to a position where the connecting portion 29D of the blade portion 29B is close to the portion connected to the casing substrate 28E. The stationary blade 28D has a side edge portion 28K on the inner fan 27F side that is formed in accordance with the angles of the casing substrate 28E and the inclined portion 28G, and is fixed to the casing substrate 28E and the inclined portion 28G.

  Here, in the wind direction plate 28C of the present embodiment, the blade portions 29B are provided radially with the fixed portion 29A as the center. The air blown from the inner fan 27F is guided by the wind direction plate 28C. However, in the portion where the fixing portion 29A is provided, air retention or backflow may occur. Therefore, the inventors changed the shape, size, position, angle, and the like of the wind direction plate 28C and the stationary blade 28D, and repeated examination and simulation. As a result, when the stationary blade 28D is provided at a position surrounding the radial wind direction plate 28C, the air blown from the inner fan 27F is restrained from staying and backflow of air by the fixed portion 29A, and the first to third The whole of the food storage rooms 22B to 22D was blown extremely uniformly. Therefore, according to the food dryer 10 of the present embodiment, it is not necessary to provide the inner fan 27F for each of the first to third food storage rooms 22B to 22D, and the apparatus can be downsized.

  Next, the configuration of the first to third food accommodation rooms 22B to 22D will be described. As shown in FIG. 2, the first to third food storage rooms 22 </ b> B to 22 </ b> D are provided with a plurality of tray mounting shelves 30 along the vertical direction. On each of the tray mounting shelves 30, a mesh-structured tray 30 </ b> T (usually called “shrimp”) can be placed. On the tray 30T, food to be dried such as fresh shiitake mushrooms, fruits and vegetables as “food to be dried” is placed.

  As shown in FIG. 3, the front wall 21X of the drying case 21 has a tray storage door 22T that opens and closes in the front-rear direction at portions corresponding to the first to third food storage rooms 22B to 22D. The tray storage door 22T is opened, and the tray 30T can be taken in and out. Each tray storage door 22 </ b> T is provided with a glass window 22 </ b> W for visually confirming a dry state of food to be dried such as shiitake mushrooms. Among the pair of side walls provided on both sides of the drying case 21 in the lateral direction, a plurality of intake holes 31 are formed in the side wall 21A on the heating chamber 22A side (hereinafter referred to as “intake side wall 21A”). Each of the plurality of intake holes 31 is arranged in a plurality (four in the illustrated example) at regular intervals along the front-rear direction. A plurality of rows (three in the illustrated example) of intake holes 31 along the front-rear direction are provided at equal intervals in the vertical direction, and are provided in a matrix at the upper portion of the intake side wall 21A.

  On the outer peripheral surface of the intake side wall 21A, a pair of rails is provided at a position sandwiching one row of intake holes 31 along the front-rear direction on both sides in the vertical direction. An opening adjustment plate 33 is supported on the pair of rails so as to be slidable in the front-rear direction. The opening adjustment plate 33 is formed with an intake hole having the same shape in accordance with the position of the intake hole 31 of the intake side wall 21A, and the intake hole of the opening adjustment plate 33 is adjusted to the position of the intake hole 31 of the intake side wall 21A. The opening of the intake hole 31 is adjusted by shifting the air flow rate so that the flow rate of the air taken in from the intake hole 31 can be adjusted.

  A secondary intake hole 32 is formed in the lower part of the intake side wall 21A in accordance with the position of a later-described secondary intake hole 45C (see FIG. 1) and the heater 25. The secondary intake holes 32 are formed in a substantially rectangular shape, as viewed from the lateral direction, whose vertical length is longer than the height of the heater 25. Therefore, the heater 25 is in a state where a part of the heater 25 is exposed from the secondary intake hole 32 when viewed from the intake side wall 21A side.

  Of the pair of side walls provided on both sides of the drying case 21 in the lateral direction, the side wall 21C (hereinafter referred to as “exhaust side wall 21C”) on the side of the third food storage room 22D opposite to the intake side wall 21A is provided. Similarly to the intake holes 31 of the intake side wall 21A, a plurality of exhaust holes 34 are formed in a row. Further, the exhaust side wall 21 </ b> C has a secondary exhaust hole 32 </ b> X formed in a substantially central portion. The secondary exhaust hole 32X has a substantially square shape when viewed from the lateral direction. The exhaust hole 34 is formed at a position surrounding the secondary exhaust hole 32X. In the exhaust side wall 21C, a plurality of exhaust holes 34 are arranged at equal intervals along the front-rear direction. A plurality of rows (three in the illustrated example) of the exhaust holes 34 along the front-rear direction are provided at equal intervals along the vertical direction above the secondary exhaust holes 32X. In addition, one row of exhaust holes 34 along the front-rear direction is arranged so that the position in the front-rear direction is alternated with another row of exhaust holes 34 adjacent in the up-down direction. The three rows of exhaust holes 34 along the front-rear direction are configured such that the opening can be adjusted by one opening adjusting plate 33X. Similarly, the exhaust side wall 21C is configured such that three rows of exhaust holes 34 are equally spaced along the vertical direction below the secondary exhaust hole 32X, and the opening degree can be adjusted by the opening degree adjusting plate 33X. . The shape, number, position, and the like of the intake holes 31, the secondary intake holes 32, the opening adjustment plate 33, the exhaust holes 34, the opening adjustment plate 33 </ b> X, and the secondary exhaust holes 32 </ b> X are examples, and can be changed as appropriate.

  Further, as shown in FIG. 6, the drying case 21 has a control unit 39 fixed at an upper position on the front side surface. The control unit 39 is connected to a temperature / humidity sensor 91 provided on an exhaust cover portion 46, which will be described later, attached to the exhaust side wall 21C by a connection cable (not shown). The control unit 39 controls the heating burner 23 and the damper drive source 95 (see FIG. 8) based on the actual temperature and the actual humidity measured by the temperature / humidity sensor 91.

(Configuration of external duct 40)
Next, the configuration of the external duct 40 will be described. As shown in FIG. 7, the external duct 40 includes an intake cover portion 45, an exhaust cover portion 46, and an intermediate connecting portion 41. First, the intermediate communication unit 41 will be described. The intermediate connecting portion 41 has a rectangular tube shape extending in the lateral direction of the food dryer main body 20, and its planar shape (shape viewed from above) is substantially the same as the planar shape of the food dryer main body 20. . The intermediate connecting portion 41 is configured, for example, by connecting four unit ducts 42 in the lateral direction. The four unit ducts 42 cover the entire upper surface of the drying case 21. The unit duct 42 is connected to, for example, a pair of unit ducts 42 on the exhaust side wall 21C side with a length adjusting wall interposed therebetween, and extends along the lateral direction of the intermediate connecting portion 41 by the length adjusting wall. The overall length is adjusted to the length of the food dryer body 20.

  The intake cover portion 45 and the exhaust cover portion 46 are formed in a substantially rectangular parallelepiped shape, the width in the front-rear direction is substantially the same as that of the food dryer main body 20, and the length in the vertical direction is the food dryer main body 20 and the intermediate connecting portion 41. It is almost the same as the combined length. The intake cover portion 45 has a lateral width larger than that of the exhaust cover portion 46. The surface of the intake cover 45 that faces the exhaust cover 46 in the lateral direction is open, and the opening is closed by the intake side wall 21A of the food dryer body 20 as shown in FIG. Similarly, the exhaust cover portion 46 is open at the side facing the intake cover portion 45 in the lateral direction, and the opening is closed by the exhaust side wall 21 </ b> C of the food dryer main body 20. As shown in FIG. 7, the intake cover portion 45 and the exhaust cover portion 46 project a pair of side cover walls 47 from both side edge portions of the main cover wall 50 disposed to face the outer surface of the intake side wall 21A or the exhaust side wall 21C. The upper and lower ends of the grooved structure thus formed are closed by the upper surface wall 48 and the lower surface wall 49. The intake cover 45 covers the entire intake side wall 21 </ b> A and is fixed to the drying case 21 with screws or the like in a state of protruding upward from the drying case 21. The exhaust cover portion 46 covers the entire exhaust side wall 21 </ b> C and is fixed to the drying case 21 with screws or the like in a state of protruding upward from the drying case 21. The intake cover portion 45 and the exhaust cover portion 46 are connected to an end portion of the intermediate connecting portion 41 at a portion protruding upward from the drying case 21, and the intake cover portion 45 and the exhaust cover portion are disposed in the internal space of the intermediate connecting portion 41. 46 internal spaces communicate.

  A pair of operation windows 51 are formed vertically on each side cover wall 47 of the intake cover portion 45 and the exhaust cover portion 46. A pair of rails 52 are provided on both side edges of the operation window 51, and a closing plate 53 is inserted between the pair of rails 52 from above to close the operation window 51. The operator operates the opening adjustment plate 33 (see FIG. 3) and the opening adjustment plate 33X inside the intake cover portion 45 and the exhaust cover portion 46 by opening the operation window 51 by shifting the closing plate 53. be able to.

  As shown in FIG. 1, the air intake cover 45 has a fan drive motor 35, which is a drive source of the fan drive shaft 27, attached to the front side surface (front side in FIG. 1). The fan drive motor 35 is provided at the edge of the main cover wall 50 side on the side surface of the intake cover portion 45 and at the approximate center in the vertical direction. As shown in FIG. 3, the end portion of the fan drive shaft 27 projects from the central portion of the intake side wall 21 </ b> A. Further, as shown in FIG. 1, the fan drive shaft 27 has a pulley 27 </ b> P fixed to a base end portion protruding outward from the insertion hole 45 </ b> H (see FIG. 7) of the main cover wall 50. A pulley 35 </ b> P of the fan drive shaft 27 is drivably coupled to a pulley 35 </ b> P fixed to the output shaft of the fan drive motor 35. Further, the pulley 27P and the pulley 35P that are drivingly connected by the belt 35B are covered with a belt cover 36 that is fixed to the main cover wall 50 of the intake cover portion 45.

  Further, as shown in FIG. 7, the intake cover portion 45 has a duct intake hole 45 </ b> A formed at a position connecting the upper end portion of the main cover wall 50 and the lateral end portion of the upper surface wall 48. The duct intake hole 45A is formed in a rectangular shape whose longitudinal direction is the longitudinal direction, and is inclined in a direction from the intake cover portion 45 toward the exhaust cover portion 46 in the lateral direction. An intake damper 45T for opening and closing the duct intake hole 45A is attached to the duct intake hole 45A. The intake damper 45T is formed in the substantially same rectangular shape as the duct intake hole 45A, and is rotatably connected to a side edge portion on the intake side wall 21A side in the duct intake hole 45A. The intake damper 45T rotates from the closed state of the duct intake hole 45A toward the intake side wall 21A to open the duct intake hole 45A.

  Further, the intake cover portion 45 is provided with a secondary intake hole 45 </ b> C at the lower portion of the main cover wall 50. The secondary intake hole 45C is formed in a rectangular shape extending in the front-rear direction. The secondary intake hole 45C is opened and closed by a secondary intake damper 45D. The secondary intake damper 45D has substantially the same rectangular shape as the secondary intake hole 45C, and is rotatably connected to the upper end portion of the secondary intake hole 45C. The secondary intake damper 45D is biased to a position that closes the secondary intake hole 45C by its own weight, and rotates to the inside of the intake cover portion 45 in response to a change in atmospheric pressure to open the secondary intake hole 45C. The secondary intake damper 45D may be configured to be biased by a spring or the like to a position where the secondary intake hole 45C is closed.

  As shown in FIG. 8, in the intake damper 45T, a rotation support shaft 45J is inserted along the front-rear direction in a portion rotatably connected to the opening of the duct intake hole 45A. The end of the rotation support shaft 45J protrudes from the front surface of the intake cover portion 45, and the intake damper manual handle 44 and the power output portion of the damper drive source 95 are connected to the protruding portion. The damper drive source 95 accommodates a speed reduction mechanism (not shown) and a motor (not shown) connected to the input side of the speed reduction mechanism in a rectangular parallelepiped gear box 95B fixed to the front surface of the intake cover 45. . A rotation support shaft 45J passes through the damper drive source 95 in the front-rear direction, and the rotation support shaft 45J is drivingly connected to the output side of the speed reduction mechanism. Therefore, the rotation support shaft 45J receives the output torque of the motor via the speed reduction mechanism, and rotates according to the driving of the motor to open and close the duct intake hole 45A.

  The intake damper manual handle 44 has an upper end fixed to a portion protruding further forward than the gear box 95B of the rotation support shaft 45J, and is attached in a state of hanging downward from the upper end. The lower end of the intake damper manual handle 44 is covered from the front by a damper opening adjustment cover 37 fixed to the front surface of the drying case 21. The damper opening adjustment cover 37 has a gate-shaped structure in which a pair of leg portions 37C project from both lateral ends of the main plate portion 37B formed with the arc-shaped slits 37A toward the front surface of the intake cover portion 45. Yes. The damper opening adjustment cover 37 has a pair of leg portions 37C fixed to the front surface of the intake cover portion 45, and a lower end portion of the intake damper manual handle 44 is located in a gap between the main plate portion 37B and the front surface of the drying case 21. Contained.

  A needle gauge 43 is attached to the intake damper manual handle 44 in accordance with the position of the main plate portion 37B. The needle gauge 43 is for visually confirming the inclination of the intake damper 45T. The needle tip position is changed in conjunction with the rotation of the intake damper 45T, and is provided on the surface of the main plate portion 37B (not shown). The inclination (angle) can be confirmed from the position indicated by the needle on the scale.

  Further, a female screw 44X is formed at the lower end of the intake damper manual handle 44, and an operation knob 93 is screwed and fixedly attached to the female screw 44X from the front of the slit 37A. The operation knob 93 has a structure in which a male screw 93B protrudes from the center of a disc-shaped knob main body 93A. The male screw 93B is screwed into the female screw 44X, and the operation knob 93 is attached to the intake damper manual handle 44. It has been. With these configurations, the intake damper 45T can be opened and closed by either automatic opening / closing using the damper drive source 95 or manual opening / closing by operating the operation knob 93, as will be described later.

  Further, as shown in FIG. 7, the exhaust cover portion 46 is provided with one duct exhaust hole 55 in the upper portion of the main cover wall 50. The duct exhaust hole 55 is formed in a rectangular shape extending in the width direction of the main cover wall 50. The duct exhaust hole 55 is opened and closed by an exhaust damper 56. The exhaust damper 56 has substantially the same rectangular shape as the duct exhaust hole 55 and is connected to the upper end of the duct exhaust hole 55 so as to be rotatable. The exhaust damper 56 is biased to a position that closes the duct exhaust hole 55 by its own weight, and opens to the duct exhaust hole 55 by rotating to the outside of the exhaust cover portion 46. A temperature / humidity sensor 91 is attached to the side cover wall 47 of the exhaust cover portion 46. The temperature / humidity sensor 91 is attached to an appropriate position so that a sensor for detecting temperature and humidity is disposed at a position close to the lower end of the duct exhaust hole 55.

  Next, the drying process of the food dryer 10 will be described. In order to start the operation of the food dryer 10, the food to be dried such as raw shiitake mushroom is placed on the tray 30T (see FIG. 2) and accommodated in the first to third food accommodating rooms 22B to 22D. The male screw 93B is left loose with respect to the female screw 44X of the intake damper manual handle 44. Then, for example, the target temperature and the target humidity are set on the operation panel of the control unit 39, and the start switch is turned on. Then, the heater 25 generates heat due to the flame generated by burning the kerosene or heavy oil by the heating burner 23, and the fan drive motor 35 drives the inner fan 27F to rotate at a constant rotational speed. The air sucked into the drying case 21 from 32 is blown laterally in the drying case 21. At this time, while the air blown in the lateral direction by the inner fan 27F flows in the blowing direction induced by the inclined portion 28G, the wind direction plate 28C, and the stationary blade 28D of the blow assisting portion 28, the air is diffused in the vertical direction. Air is efficiently blown in the lateral direction. Hot air heated by the heater 25 passes through the first to third food accommodation rooms 22B to 22D and is discharged from the exhaust hole 34 and the secondary exhaust hole 32X.

  The control unit 39 changes the output of the heating burner 23 according to the deviation between the target temperature (set temperature) and the temperature actually measured by the temperature / humidity sensor 91 in the exhaust cover section 46. The control unit 39 determines whether or not the actually measured humidity measured by the temperature / humidity sensor 91 matches the target humidity (set humidity). If the measured humidity exceeds the target humidity, the damper drive source At 95, the intake damper 45T is rotated and opened. Then, the flow of the air on the intermediate communication part 41 side from the opened intake damper 45T, that is, the air flow passing through the intermediate communication part 41 from the exhaust hole 34 and the secondary exhaust hole 32X is regulated, and the internal pressure rises. As a result, the exhaust damper 56 is opened. Thereby, a part of the air exhausted from the exhaust hole 34 and the secondary exhaust hole 32X is exhausted from the duct exhaust hole 55, while outside air is sucked from the duct intake hole 45A according to the amount of air to be exhausted. . Further, the air that has been exhausted from the exhaust hole 34 and the secondary exhaust hole 32X but not exhausted from the duct exhaust hole 55 passes through the intermediate connecting portion 41 as reusable heated air, and the outside air from the duct intake hole 45A. To join. Then, the reused heated air and the outside air are mixed and sucked into the food dryer main body 20 through the intake holes 31 and the secondary intake holes 32. At this time, the humidity is lowered by mixing the heated air and the outside air, and the actually measured humidity by the temperature / humidity sensor 91 is also lowered. When the actually measured humidity falls below the target humidity, the intake damper 45T operates in a closing direction, and the ratio of heated air increases from the intake amount of outside air. Note that when the heated air and the outside air are mixed, the measured temperature is lowered together with the measured humidity, so that the control unit 39 increases the output of the heating burner 23.

  Here, the temperature / humidity sensor 91 is attached to an appropriate position of the side cover wall 47 of the exhaust cover portion 46 in accordance with the position of the duct exhaust hole 55. Humidity and temperature of air blown from the fan drive shaft 27 is detected by the temperature / humidity sensor 91 immediately after passing through the first to third food storage rooms 22B to 22D. For this reason, the temperature / humidity sensor 91 can accurately detect the humidity and temperature in the first to third food accommodation rooms 22B to 22D. Therefore, the control unit 39 controls the heating burner 23 and the damper drive source 95 based on the detection value of the temperature / humidity sensor 91, thereby setting the first to third food storage rooms 22B to 22D to a desired temperature and humidity. It becomes possible.

  Further, the intake cover portion 45 is provided with a secondary intake hole 45 </ b> C at the lower portion of the main cover wall 50. The secondary intake hole 45 </ b> C is opened and closed when the air pressure in the intake cover 45 changes due to the opening and closing of the duct intake hole 45 </ b> A and the exhaust damper 56. The outside air taken in from the secondary intake hole 45C is blown into the heating chamber 22A through the secondary intake hole 32 of the intake side wall 21A, and cools the heater 25. Accordingly, it is possible to prevent the heater 25 from being heated excessively when the outside air taken in from the duct intake hole 45A does not reach the lower part of the intake cover portion 45 sufficiently. Further, according to the food dryer 10 of the present embodiment, by changing the size and shape of the secondary intake damper 45D, the resistance force to the rotation direction, etc., the amount of outside air taken in from the secondary intake hole 45C, that is, heating The cooling function of the vessel 25 can be adjusted.

  The food dryer main body 20 and the external duct 40 are preferably completely sealed when the duct intake hole 45A, the exhaust damper 56, and the secondary intake damper 45D are closed. However, it may be difficult to completely seal the inside of the food dryer main body 20 and the external duct 40 from the viewpoint of structure or manufacturing cost. For this reason, when the outflow of air occurs at the connecting portion of the tray storage door 22T or the unit duct 42, the secondary intake hole 45C can be opened by utilizing the outflow of air.

  Incidentally, the food dryer 10 can be switched from the normal mode to the damper manual mode by operating the operation panel provided in the control unit 39. In the damper manual mode, power is not supplied to the damper drive source 95, and the operator can manually open and close the intake damper 45T by operating the operation knob 93. In this case, the operation knob 93 may be tightened after the male screw 93B of the operation knob 93 is loosened with respect to the female screw 44X of the intake damper manual handle 44 and the intake damper 45T is set to an arbitrary opening degree. Then, the edge of the slit 37A in the damper opening adjustment cover 37 is tightened between the knob main body 93A of the operation knob 93 and the intake damper manual handle 44, so that the intake damper 45T can be fixed at an arbitrary rotation position. it can. Thereby, the intake amount of the outside air during operation of the food dryer 10 can be arbitrarily changed based on the experience of the operator.

As mentioned above, according to above-mentioned embodiment, there exist the following effects.
<Effect 1> The food dryer 10 drives the inner fan 27F to take in the air heated from the intake holes 31 and the secondary intake holes 32 of the intake side wall 21A of the drying case 21 and heated by the heater 25. The air is blown toward the food to be dried in the third food storage rooms 22B to 22D, and is discharged from the exhaust hole 34 and the secondary exhaust hole 32X of the exhaust side wall 21C. The casing 28B connects the outer peripheral portion 28I that surrounds the outer periphery of the inner fan 27F and the inner peripheral surface of the drying case 21, and the interior space of the drying case 21 is accommodated in the first to third foods with the inner fan 27F interposed therebetween. It is divided into the rooms 22B to 22D side and the intake side wall 21A side. Thus, the air blown from the inner fan 27F is efficiently blown toward the first to third food storage rooms 22B to 22D while the direction of the blown air is guided by the outer peripheral portion 28I and the casing 28B. Further, the inner fan 27 </ b> F is suppressed by the casing 28 </ b> B that defines the internal space of the drying case 21, so that the blown air is prevented from wrapping behind the inner fan 27 </ b> F (the intake cover part 45 side). Thereby, inner fan 27F will be pulled out as much as possible, and it will become possible to increase the volume of the air which blows toward the 1st-3rd food storage rooms 22B-22D. Conventionally, the inner fan 27F corresponding to each of the first to third food accommodation rooms 22B to 22D has been provided. However, in the food dryer 10 according to the present embodiment, one inner fan is obtained by increasing the blowing efficiency. Only 27F makes it possible to supply sufficient air to each of the rooms 22B to 22D, and the apparatus is reduced in size by not providing a fan. Moreover, conventionally, since it was necessary to provide a plurality of fans according to each of the rooms 22B to 22D, the fan drive shaft 27 shown in FIG. 2 is provided on the air inlet side in the tray mounting shelf 30 of the third food storage room 22D. It was necessary to extend in the lateral direction to a close position. On the other hand, in the food dryer 10 of the present embodiment, the lateral length of the fan drive shaft 27 is shortened, and the fan drive shaft 27 does not penetrate the rooms 22B to 22D laterally. Therefore, when the worker puts and removes the food to be dried in the first to third food storage rooms 22B to 22D, a carriage that transports the food to be dried and an instrument that holds the food to be dried (for example, fishing of food to be dried) Etc.) and the work efficiency is improved.

<Effect 2> The heated air blown from the inner fan 27F is guided by the wind direction plate 28C included in the blow assisting unit 28 and blown toward the first to third food accommodation rooms 22B to 22D. Thereby, in the said food dryer 10, it becomes possible to prevent the residence of the air blown and to distribute the heated air uniformly by the whole 1st-3rd food storage room 22B-22D, and ventilation efficiency is improved. More improved.

<Effect 3> The fixing portion 29A of the wind direction plate 28C is provided on the axis of the rotation axis of the inner fan 27F. Each of the plurality of blade portions 29B spreads radially from the fixed portion 29A in a direction orthogonal to the rotation axis of the fan drive shaft 27, and at a predetermined angle (45 with respect to a plane orthogonal to the fan drive shaft 27). Degree). As a result, the air blown from the inner fan 27F becomes a stream of air in a cyclonic vortex formed by a plurality of blade portions 29B formed by twisting at 45 degrees, and is heated by the heater 25 and has different temperatures and humidity. Will be blown toward the first to third food accommodation rooms 22B to 22D while being stirred. Therefore, according to the said food dryer 10, it becomes possible to blow air with a more uniform temperature difference etc. toward the 1st-3rd food storage rooms 22B-22D. Moreover, it becomes possible to change the aspect of an airflow by adjusting the angle, shape, etc. of the blade | wing part 29B.

<Effect 4> Each of the stationary blades 28D is formed at each of the four corners in the inner peripheral portion of the casing 28B formed in a box shape. As a result, the air blown from the inner fan 27F is restrained from gas retention and backflow by the fixed portion 29A, and is blown extremely uniformly throughout the first to third food storage rooms 22B to 22D.

<Effect 5> The pair of inclined portions 28G of the casing 28B are inclined so as to spread outward so that the distance in the vertical direction facing each other becomes longer as they go from the base end portion of the fan drive shaft 27 to the distal end portion. . Thereby, since the air blown from the inner fan 27F flows along the inclination of the inclined portion 28G, it is possible to reduce the possibility of gas stagnation and eddy currents and further improve the blowing efficiency.

<Effect 6> The first to third food accommodation rooms 22B to 22D are arranged adjacent to each other in the lateral direction. For this reason, according to the said food drying machine 10, size reduction of an apparatus is attained further, aiming at the improvement of ventilation efficiency.

<Effect 7> In the food dryer 10, the high-temperature air exhausted from the exhaust hole 34 and the secondary exhaust hole 32X to the outside of the drying case 21 passes through the external duct 40 and the intake hole 31 and the secondary intake hole 32. Since the air is sucked into the drying case 21, the heat energy used by the heater 25 to heat the air can be effectively used, the fuel consumption can be improved, and the manufacturing cost of the food to be dried can be reduced.

  Incidentally, the 1st-3rd food accommodation room 22B-22D in this embodiment is an example of the mounting part in which drying object food is mounted. The fan drive shaft 27 is an example of the rotating shaft of the inner fan. The secondary intake hole 32 is an example of an intake hole. The secondary exhaust hole 32X is an example of an exhaust hole.

Note that the present invention is not limited to the above-described embodiment, and it goes without saying that various improvements and modifications can be made without departing from the spirit of the present invention.
For example, the shape, number, fixed angle, and the like of the wind direction plate 28C in the above embodiment are examples, and can be changed as appropriate. For example, the blade portion 29 </ b> B of the wind direction plate 28 </ b> C may be formed of a flat plate having a plane along the axis of the rotation axis of the fan drive shaft 27. Further, for example, the blade portion 29 </ b> B may be configured to be provided on one side in the vertical direction with respect to the fan drive shaft 27. Further, the blade portions 29B may be formed at different pitches in the circumferential direction of the fixed portion 29A.

  For example, as shown in FIG. 9, the air blow assisting unit 28 may include a plurality of wind direction plates 28 </ b> M such that the fan drive shaft 27 is interposed between the vertical inclined portion 28 </ b> G and the flat plate portion 28 </ b> H. Good. Note that FIG. 9 illustrates only two wind direction plates 28M at both ends in the vertical direction among a plurality of wind direction plates 28M arranged in the vertical direction in order to prevent the drawing from being complicated. The plurality of wind direction plates 28M are held at both ends in the front-rear direction with respect to the side plate 28F, and are configured to be rotatable in the up-down direction with respect to a rotation shaft 28N provided along the front-rear direction. It is adjustable. The air blown from the inner fan 27F is guided to a plurality of air passages partitioned by a wind direction plate 28M provided side by side in the vertical direction, and is blown toward the first to third food storage rooms 22B to 22D. . Further, by adjusting the wind direction of the wind direction plate 28 </ b> M, the blown air is blown so as to radiate in the vertical direction with respect to the axial direction of the fan drive shaft 27. Thereby, the heated air will spread throughout the vertical direction of the first to third food storage rooms 22B to 22D.

  As shown in FIG. 9, the casing substrate 28E may have a configuration in which a mouth ring 28A is attached to a hole in the outer peripheral portion 28I. The mouth ring 28A is formed in a cylindrical shape, and the inner peripheral surface is fixed at a position where a predetermined interval is provided between the tip of the blade 27T so as to surround the blade 27T of the inner fan 27F. On the inner peripheral surface of the mouth ring 28A, in order to increase the air blowing efficiency, the inner diameter decreases in the lateral direction from the proximal end portion of the fan drive shaft 27 toward the distal end portion (the first food containing room 22B side). An inclination is provided. The food dryer 10 can adjust the amount and mode of air to be blown by providing such a mouth ring 28A.

Moreover, in the said embodiment, although the temperature / humidity sensor 91 was provided in the exhaust cover part 46, it is not limited to this. For example, the temperature / humidity sensor 91 may be provided in the intake cover portion 45. Or you may provide the temperature / humidity sensor 91 in multiple places. Moreover, you may provide a temperature sensor and a humidity sensor separately.
Further, the drying case 21 and the external duct 40 are not limited to metal, and may be composed of other members. For example, the drying case 21 may be composed of a heat insulating board. For example, the external duct 40 may have a structure in which a vinyl sheet is stretched on a pipe frame.
Further, two or more inner fans 27F may be provided.

  The drying case 21 may have a configuration in which one or both of the opening adjustment plate 33 of the intake side wall 21A and the opening adjustment plate 33X of the exhaust side wall 21C are not attached. In this case, since it is not necessary to change the position of the opening adjustment plate 33 and the like, the operation windows 51 and the like of the intake cover portion 45 and the exhaust cover portion 46 can be eliminated.

Further, the drying case 21 and the external duct 40 are not limited to a rectangular parallelepiped shape, but may have other shapes (such as a cylindrical shape).
Moreover, in the said embodiment, although the intermediate connection part 41 of the external duct 40 was arrange | positioned above the food dryer main body 20, the intermediate connection part 41 is arrange | positioned along the rear surface of the food dryer main body 20, for example. It is good also as a structure.
In the above embodiment, the external duct 40 has a structure in which the duct intake hole 45A and the intake damper 45T are provided in the intake cover portion 45. However, the external duct 40 is provided on the upper surface of the intermediate connecting portion 41, for example. Also good.

Further, the food to be dried is not limited to fresh shiitake mushrooms, but may be seaweed, vegetables, and the like.
Moreover, the gas which heats and blows is not restricted to air. For example, a gas having a higher thermal conductivity than air may be circulated.

DESCRIPTION OF SYMBOLS 10 Food dryer, 21 Drying case, 21A Intake side wall, 21C Exhaust side wall, 21F, 21G Vent hole, 25 Heater, 27 Fan drive shaft, 27F Inner fan, 28B Casing, 28C Wind direction plate, 28I Outer part, 29A Fixed part , 29B blade part, 28D stationary blade, 28G inclined part, 30 tray mounting shelf, 31 intake hole, 34 exhaust hole, 40 external duct.

Claims (7)

A drying case having an intake side wall provided with an intake hole and an exhaust side wall provided with an exhaust hole;
A heater that is provided in the drying case and heats the gas sucked from the air intake hole;
A placement unit provided in the drying case and on which the food to be dried is placed;
The gas that is rotatably held in the drying case, sucked from the air intake hole, and heated by the heater is blown toward the food to be dried of the placement unit from the exhaust hole of the exhaust side wall. An inner fan to be discharged,
The outer peripheral portion surrounding the outer periphery of the inner fan is connected to the inner peripheral surface of the drying case, and the inner space of the drying case is connected to the placement portion side and the intake sidewall side with the inner fan interposed therebetween. A casing to partition;
A food dryer comprising:   The food dryer according to claim 1, further comprising a wind direction plate for guiding the flow of the gas in a direction from the inner fan toward the mounting portion.   The wind direction plate has a fixed portion provided on an axis of the rotation axis of the inner fan, and a plane extending radially from the fixed portion in a direction orthogonal to the rotation axis and orthogonal to the rotation axis. The food dryer according to claim 2, further comprising: a plurality of blade portions having a predetermined angle.   The casing is formed in a box shape that surrounds the wind direction plate, and is provided with stationary blades that guide the gas flow in the direction from the inner fan toward the mounting portion at the four corners of the inner periphery thereof. The food dryer according to claim 2 or claim 3, characterized by the above.   The food dryer according to any one of claims 1 to 4, wherein the casing is provided with an inclined portion that is inclined from the outer peripheral portion toward the mounting portion.   The food dryer according to any one of claims 1 to 5, further comprising a plurality of placement units, wherein the plurality of placement units are arranged adjacent to each other.   The food dryer according to any one of claims 1 to 6, further comprising an external duct that circulates the gas exhausted from the exhaust hole to the outside of the drying case toward the intake hole side. .

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