Vacuum microwave thawing machine

Abstract

To provide a vacuum microwave thawing machine capable of effectively diffusing microwaves and uniformly irradiating the object to be thawed with the microwaves.SOLUTION: The thawing device is provided with a thawing chamber R1 for storing an object to be thawed, a decompressor 30 for decompressing the inside of the thawing chamber R1, a microwave generator 34 for generating microwaves to be irradiated into the thawing chamber R1, an irradiation port 42 provided on a wall surface part 20D forming the thawing chamber R1 and for irradiating the microwaves into the thawing chamber R1, and a stirrer 50 for diffusing the microwaves into the thawing chamber R1, and the stirrer 50 is moved along the wall surface part 20D and reciprocated so as to cross the irradiation port 42.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a vacuum microwave thawing machine. [Background technology]

[0002] Vacuum microwave thawing machines have been known for some time, irradiating microwaves onto an object to be thawed in a reduced pressure state (or vacuum state) lower than atmospheric pressure to thaw the object, and one example is described in Patent Document 1 below. Vacuum microwave thawing machines repeatedly perform heating with microwaves and sublimation cooling under reduced pressure, thereby suppressing temperature variations between the surface and the core and thawing the food material without destroying its cells. In order to irradiate the object to be thawed evenly with microwaves, the vacuum microwave thawing machine described in Patent Document 1 below is configured to provide a turntable in a thawing chamber that contains the object to be thawed, and irradiate the object with microwaves while rotating the object on the turntable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-74862 Summary of the Invention [Problem to be solved by the invention]

[0004] The vacuum microwave thawing machine described in Patent Document 1 has a rectangular parallelepiped-shaped thawing chamber, and even if a disk-shaped turntable is placed inside the thawing chamber, the corners of the thawing chamber become wasted space. To address this issue, a vacuum microwave thawing machine equipped with a rotary stirrer to diffuse microwaves in the thawing chamber has been considered. However, because this rotary stirrer is located on a rectangular wall, although it can diffuse microwaves within a circular area, there are still some areas that the stirrer cannot reach. Therefore, there is a problem in that it is difficult to sufficiently diffuse microwaves using only a rotary stirrer.

[0005] The present invention has been made in consideration of such circumstances, and its object is to provide a vacuum microwave thawing machine that can effectively diffuse microwaves and uniformly irradiate the microwaves onto the item to be thawed. [Means for solving the problem]

[0006] In order to solve the above problems, the vacuum microwave thawing machine disclosed in the present application has the following structure. (1) a thawing chamber for accommodating an object to be thawed; a pressure reducer for reducing the pressure inside the thawing chamber; a microwave generator that generates microwaves to be irradiated into the thawing chamber; an irradiation port provided in a wall portion forming the thawing chamber and irradiating the microwave toward the thawing chamber; a stirrer for diffusing the microwaves into the thawing chamber; Equipped with The stirrer moves along the wall surface and reciprocates across the irradiation port.

[0007] In a vacuum microwave thawing machine, the irradiation port for irradiating microwaves into the thawing chamber is generally provided in the center of one of the wall portions forming the thawing chamber in order to radiate microwaves evenly throughout the chamber. In a vacuum microwave thawing machine, the irradiation port must be configured to transmit microwaves but not air in order to reduce the pressure in the thawing chamber, and the irradiation port may be blocked by glass. In this configuration, it is difficult to provide a stirrer on the glass of the irradiation port, and a rotating stirrer must be provided near the irradiation port. However, the size of the rotating stirrer is small so that it does not come into contact with the surrounding wall portions, and the stirrer does not reach the irradiation port sufficiently, making it difficult to sufficiently diffuse the microwaves.

[0008] In contrast, the vacuum microwave thawing machine disclosed in the present application has a stirrer that moves back and forth across the irradiation port, for example by rocking or sliding, thereby effectively diffusing the microwaves emitted from the irradiation port and enabling the microwaves to be evenly irradiated onto the item to be thawed.

[0009] Furthermore, the vacuum microwave thawing device having the above-described configuration can be configured in various ways as shown below.

[0010] (2) The vacuum microwave thawing machine according to (1), wherein the stirrer is rotatably provided on the wall portion and swings across the irradiation port.

[0011] (3) The vacuum microwave thawing machine according to (1), wherein the stirrer is provided so as to be slidable along the wall surface portion.

[0012] The above two configurations of the vacuum microwave thawing machine are embodied in a configuration in which the stirrer moves back and forth, and can effectively diffuse the microwaves emitted from the irradiation port.

[0013] (4) The vacuum microwave thawing machine according to any one of (1) to (3), wherein the stirrer has a long hole formed therethrough, the long hole having a length equal to or less than half the wavelength of the microwave.

[0014] Microwaves cannot pass through holes with a diameter of less than half the wavelength. In other words, in a vacuum microwave thawing device with this configuration, the long holes with a width of less than half the wavelength of the microwaves provided in the stirrer do not allow microwaves to pass through, and instead act like uneven surfaces on the stirrer. Therefore, in a vacuum microwave thawing device with this configuration, the stirrer diffuses the microwaves, allowing the microwaves to be more effectively diffused within the thawing chamber.

[0015] (5) The thawing chamber is provided with a placement section on which the object to be thawed is placed, a shielding material for blocking a part of the microwaves directed from the irradiation port toward the object to be thawed placed on the placement section; The vacuum microwave thawing machine according to any one of items (1) to (4), wherein the shielding material has a slit extending in the horizontal direction and having a width in the up-down direction that is equal to or less than half the wavelength of the microwaves.

[0016] In a vacuum microwave thawing device with this configuration, the slits in the shielding material extend horizontally, allowing the horizontal component of the microwaves to pass through, while the vertical width is less than half the wavelength of the microwaves, blocking (reflecting) the vertical component of the microwaves. Therefore, in a vacuum microwave thawing device with this configuration, the presence of the shielding material can block most of the microwaves traveling from the irradiation port toward the object to be thawed, and in particular, it can block most of the microwaves traveling directly from the irradiation port toward the object to be thawed, thereby preventing concentrated heating of the object to be thawed. Furthermore, the slits in the shielding material, like the long holes in the stirrer, act as irregularities to the microwaves, causing them to be diffused and effectively diffused within the thawing chamber.

[0017] (6) The vacuum microwave thawing machine according to (5), wherein the shielding material is fixed to a wall surface portion that forms the thawing chamber between the irradiation port and the placing portion.

[0018] Since the shielding material is fixed to the wall surface that forms the thawing chamber, they are at the same potential, and no discharge occurs between the shielding material and the wall surface. Therefore, this vacuum microwave thawing device can prevent the effects of discharge between the shielding material and the wall surface on the items to be thawed.

[0019] (7) A plurality of trays are provided as the placement unit, and a rack is provided that can store the plurality of trays, The vacuum microwave thawing machine according to (5), wherein the shielding material is fixed to the rack.

[0020] In a vacuum microwave thawing machine with this configuration, there is no need to provide a member for placing a tray or a member for attaching a shielding material to the inner wall portion that forms the thawing chamber, and the inner wall portion that forms the thawing chamber has few irregularities. Therefore, in a vacuum microwave thawing machine with this configuration, by removing the rack, the workability when cleaning the inside of the thawing chamber can be improved.

[0021] (8) A cover member is provided to cover the stirrer and is capable of transmitting the microwave, The vacuum microwave thawing machine according to claim 5, wherein the shielding material is fixed to the cover member.

[0022] In a vacuum microwave thawing machine with this configuration, a cover member is provided to prevent the stirrer from coming into contact with the user when inserting their hand into the thawing chamber, and a shielding material is fixed to this cover member. With a vacuum microwave thawing machine with this configuration, the number of members required to attach the shielding material or cover member to the inner wall portion of the thawing chamber can be reduced. Furthermore, when cleaning the thawing chamber, the shielding material can be removed along with the cover member, improving workability during cleaning.

[0023] (9) A plurality of trays are provided as the placement portion, The thawing chamber is configured to be able to store a plurality of the trays in a vertically aligned state, The tray has a vertical wall portion extending in a vertical direction at an edge portion on the irradiation port side, The vacuum microwave thawing machine according to (5), wherein the slit is formed by a vertical gap between the upright wall portions of two trays arranged vertically in the thawing chamber, the vertical gap having a width equal to or less than half the wavelength of the microwaves, and the upright wall portions of the plurality of trays constitute the shielding material.

[0024] In a vacuum microwave thawing device with this configuration, simply by placing a tray with the items to be thawed inside the thawing chamber, a shielding material is formed, which can block part of the microwaves directed from the irradiation port toward the items to be thawed. Therefore, in a vacuum microwave thawing device with this configuration, there is no need to provide a member for attaching the shielding material to the inner wall portion that forms the thawing chamber, and the interior of the thawing chamber can be simplified. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a vacuum microwave thawing device that can effectively diffuse microwaves and uniformly irradiate the microwaves onto the object to be thawed. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view of a vacuum microwave thawing machine according to a first embodiment of the present invention; [Figure 2] Side cross-sectional view of a vacuum microwave defroster [Figure 3] Cross-sectional view of a vacuum microwave defroster [Figure 4] Front cross-sectional view of a vacuum microwave defroster [Figure 5] A diagram showing the irradiation port and two stirrers on the rear wall. [Figure 6] Cross-sectional view of a vacuum microwave defroster from below [Figure 7] A cross-sectional view showing the sealing structure of the stirrer (an enlarged view of the main part of Figure 2) [Figure 8] FIG. 1 is a perspective view showing the frame structure of the defroster body. [Figure 9] A perspective view of the vacuum microwave defroster from the rear bottom [Figure 10] A perspective view showing the installation of an inverter filter [Figure 11] A perspective view of the vacuum microwave defroster from the front bottom [Figure 12] A plan view showing the vicinity of the exhaust port of the pump motor [Figure 13] 13 is a perspective view of the oil collecting member shown in FIG. 12; [Figure 14] FIG. 10 is a front cross-sectional view showing the main parts of a vacuum microwave thawing device according to a second embodiment. [Figure 15] 10 is a side cross-sectional view showing a main part of a vacuum microwave thawing device according to a third embodiment. [Figure 16] 10 is a side cross-sectional view showing a main part of a vacuum microwave thawing device according to a fourth embodiment. [Figure 17] A side cross-sectional view showing a main part of a vacuum microwave thawing device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] <Embodiment 1> A vacuum microwave thawing machine 10 according to a first embodiment of the present invention will be described with reference to Figures 1 to 6. The vacuum microwave thawing machine 10 of this embodiment performs microwave heating at time intervals while the pressure inside the thawing chamber R1 is reduced, and the microwave heating and sublimation cooling due to the reduced pressure are repeated, making it possible to thaw food without destroying the cells of the food while suppressing temperature variations between the surface and the core. Note that in some of the drawings, the symbols F, B, L, R, U, and D are used to indicate directions, and respectively represent the near side (front side), far side (rear side), left side, right side, upper side, and lower side when the vacuum microwave thawing machine 10 is viewed from the front.

[0028] 1 to 3, the vacuum microwave thawing machine 10 of this embodiment includes a box-like thawing machine body 11 having a horizontally elongated rectangular parallelepiped shape and opening at the front, a door 12 for opening and closing a thawing chamber R1 disposed on the right side of the thawing machine body, a front panel 13 for covering the front of a machine chamber R2 disposed on the left side of the thawing machine body 11, and four casters 14 provided at the four corners of the underside of the thawing machine body. The vacuum microwave thawing machine 10 of this embodiment is a table-type machine that has a top plate 15 disposed on the top surface of the thawing machine body 11 and can be moved by the four casters 14.

[0029] The thawing machine main body 11 has a chamber 20 on its right side. The chamber 20 is made of a metal such as stainless steel and is a roughly rectangular box with a front opening 21. A door 12 closes the front opening 21 of the chamber 20, and the chamber 20 and the door 12 together form a thawing chamber R1 inside. The door 12 is rotatable by a hinge 22 provided at the right end of the front side of the thawing machine main body and can be opened to the right. By opening the door 12, items to be thawed can be placed in or removed from the chamber 20. Furthermore, a lever 12A provided on the door 12 allows the door 12 to be closed while firmly in contact with the chamber 20, making the thawing chamber R1 an airtight space.

[0030] The chamber 20 is provided with shelf supports 25 for accommodating trays (shelf boards) 24 as placement sections on which to place the items to be thawed. The shelf supports 25 are provided in pairs on the left and right sides of the left wall surface 20A and the right wall surface 20B of the chamber 20. A plurality of shelf supports 25 (four pairs in this embodiment) are provided at intervals in the vertical direction. This allows the chamber 20 to accommodate multiple levels (four levels) of trays 24 along the vertical direction. The shelf supports 25 are formed from pipe members made of stainless steel or the like, and are attached so as to protrude into the chamber 20 from the left and right wall surfaces 20A, 20B in a U-shape when viewed from above.

[0031] 3 and 4, the vacuum microwave thawing machine 10 of this embodiment includes a vacuum pump (pressure reducer) 30 that reduces the pressure inside the chamber 20 (thawing chamber R1), a first adjustment valve 32 and a second adjustment valve 33 that restore (increase) the pressure inside the chamber 20, a magnetron 34 (microwave generator) that generates microwaves, an inverter 35 that controls the output of the magnetron 34, and a control box 36 that houses a control board, etc. The vacuum pump 30, first adjustment valve 32, second adjustment valve 33, magnetron 34, inverter 35, and control box 36 are arranged inside the machine room R2.

[0032] As shown in FIG. 4, the vacuum pump 30 is connected to the ceiling wall surface 20C of the chamber 20 by piping 37, and sucks in air from within the chamber 20 through the piping 37 to reduce the pressure in the thawing chamber R1. Meanwhile, the first adjustment valve 32 and the second adjustment valve 33 increase the pressure in the thawing chamber R1 by allowing outside air to flow into the chamber 20. As shown in FIGS. 3 and 4, the first adjustment valve 32 and the second adjustment valve 33 are connected to a piping 38 extending from the left wall surface 20A of the chamber 20. The piping 38 branches, and the first adjustment valve 32 and the second adjustment valve 33 are connected to the respective ends. Note that the first adjustment valve 32 and the second adjustment valve 33 are both solenoid valves, but the first adjustment valve 32 is capable of adjusting the flow rate, while the second adjustment valve 33 is capable of switching between open and closed. In other words, the first adjusting valve 32 is for finely adjusting the pressure in the thawing chamber R1 during the thawing operation, and the second adjusting valve 33 is for allowing outside air to flow into the thawing chamber R1 all at once after the thawing is completed, etc., to return the pressure in the thawing chamber R1 to atmospheric pressure.

[0033] The magnetron 34 is disposed at the rear left of the chamber 20. The magnetron 34 emits microwaves into a metallic waveguide 40. The waveguide 40 extends laterally at the rear of the chamber 20, and its tip is connected to the rear wall 20D of the chamber 20. An irradiation port 42 is formed in approximately the center of the rear wall 20D of the chamber 20, and microwaves propagating through the waveguide 40 are emitted into the chamber 20 from the irradiation port 42. The irradiation port 42 is covered by a lid 44 made of a material that transmits microwaves but blocks the passage of gas, such as glass. This lid 44 allows the microwaves to be emitted from the irradiation port 42 into the thawing chamber R1 while creating a vacuum in the thawing chamber R1.

[0034] The vacuum microwave thawing machine 10 of this embodiment includes three stirrers 50, 52, and 54 for diffusing microwaves emitted into the thawing chamber R1. The first stirrer 50 and the second stirrer 52 are provided on the rear wall surface 20D of the chamber 20. Specifically, as shown in FIG. 5, the first stirrer 50 is provided on the upper right of the rear wall surface 20D, and the second stirrer 52 is provided on the lower left of the rear wall surface 20D, and they are positioned opposite each other across the irradiation port 42. The third stirrer 54 is provided on the ceiling wall surface 20C, as shown in FIG. 6. Since the first stirrer 50 is a feature of this embodiment, the second stirrer 52 and the third stirrer 54 will be described first.

[0035] The second stirrer 52 and the third stirrer 54 each include a rotating antenna 52A, 54A and a motor 52B, 54B that rotates the rotating antenna 52A, 54A. The second stirrer 52 and the third stirrer 54 have substantially the same configuration, although the rotating antennas 52A, 54A differ in size. The rotating antennas 52A, 54A are disk-shaped and rotated by the motors 52B, 54B around their center axes. The rotating antennas 52A, 54A have openings 53, 55 formed in various shapes, such as elongated holes, generally fan-shaped, or triangular. The motors 52B, 53B are located outside the chamber 20, i.e., behind the rear wall 20D and above the ceiling wall 20C, respectively. Their rotation shafts are inserted into the chamber 20 to connect the rotating antennas 52A, 54A.

[0036] The rotating antenna 52A of the second stirrer 52 has a diameter that prevents it from coming into contact with the left side wall 20A or bottom 20E of the chamber 20. As shown in Fig. 6, the rotating antenna 54A of the third stirrer 54 is disposed forward of the first stirrer 50 and has a diameter that prevents it from coming into contact with the first stirrer 50 and the door 12. Incidentally, as shown in Fig. 4, the rotating antenna 54A of the third stirrer 54 is disposed at a height that prevents it from coming into contact with the antenna 60 of the first stirrer 50 in the vertical direction.

[0037] Next, the first stirrer 50 will be described. Like the second stirrer 52 and the third stirrer 54, the first stirrer 50 is also composed of an antenna 60 and a motor 62, but the shape of the antenna 60 is different. If the rotary antenna 52A of the second stirrer 52 described above has a diameter that does not abut against the left wall surface 20A or bottom surface 20E of the chamber 20, it will not overlap with the irradiation port 42. Therefore, a stirrer having this disk-shaped antenna cannot directly diffuse the microwaves emitted from the irradiation port 42.

[0038] Therefore, as shown in FIG. 5 , the antenna 60 of the first stirrer 50 has a disk portion 64 of the same size and shape as the rotating antenna 52A of the second stirrer 52, and an extension portion 65 extending radially from the disk portion 64. The extension portion 65 extends with a constant width and is generally rectangular. In other words, when the antenna 60 is rotated by the motor 62, the extension portion 65 passes in front of the irradiation port 42. However, the first stirrer 50 is configured to swing the antenna 60 within a predetermined angular range so that the extension portion 65 does not abut against the ceiling wall surface portion 20C and the right side wall surface portion 20B. In other words, the first stirrer 50 reciprocates such that the extension portion 65 moves along the rear wall surface portion 20D and crosses the irradiation port 42.

[0039] The extending portion 65 has a plurality of elongated holes 66 formed therethrough. The length of the elongated holes 66 is equal to or less than half the wavelength of the microwaves (approximately 12 cm in this embodiment). Microwaves have the property of being unable to pass through holes with a diameter equal to or less than half the wavelength, and therefore cannot pass through the elongated holes 66 of the extending portion 65. However, due to the presence of the elongated holes 66, the extending portion 65 acts like an uneven surface for the microwaves. In other words, when microwaves hit the extending portion 65, they are diffused, allowing them to be diffused more effectively.

[0040] The length of the extension portion 65 is set so that when the antenna 60 is swung, the trajectory of the tip of the extension portion 65 comes into contact with the edge of the irradiation port 42 or is slightly outside the edge. In other words, once the antenna 60 is swung, the extension portion 65 crosses the entire irradiation port 42, and the microwaves immediately after being emitted from the irradiation port 42 can be effectively diffused.

[0041] Note that, if the antenna 60 of the first stirrer 50 does not overlap the irradiation port 42, the microwaves emitted from the irradiation port 42 will be directed toward the object to be thawed placed on the tray 24. If a large amount of microwaves are directed directly toward the object to be thawed from the irradiation port 42, uneven heating may occur. Therefore, the vacuum microwave thawing device 10 of this embodiment is provided with a shielding plate (an example of a shielding material) 70 for blocking a portion of the microwaves directed directly toward the object to be thawed from the irradiation port 42.

[0042] The shielding plate 70 is made of a metal plate such as stainless steel and is attached to the rear wall surface portion 20D. As shown in FIGS. 2 to 4 and 6 , the shielding plate 70 has a main body portion 70A that stands parallel to the rear wall surface portion 20D between the first stirrer 50, the second stirrer 52, and the shelf support 25, a protruding portion 70B that protrudes forward from the upper end of the main body portion 70A, and mounting portions 70C that extend rearward from the left and right side edges of the main body portion 70A and are used for mounting to the chamber 20. Furthermore, as shown in FIG. 4 , the main body portion 70A has multiple slits 72 that extend left and right. The multiple slits 72 are formed at a height where the shelf support 25 is provided and at a height between two shelf supports 25 that are arranged vertically.

[0043] Each of the multiple slits 72 has a width (vertical dimension) that is less than half the wavelength of the microwaves. Because the slits 72 extend horizontally, they allow horizontal components of the microwaves to pass through. However, because their vertical width is less than half the wavelength of the microwaves, they can block (reflect) vertical components of the microwaves. Therefore, the shielding plate 70 can block most of the microwaves traveling from the irradiation port 42 toward the object to be thawed. In particular, it can block most of the microwaves traveling directly from the irradiation port 42 toward the object to be thawed, thereby preventing concentrated heating of the object to be thawed. Furthermore, the slits 72 of the shielding plate 70, like the elongated holes 66 of the first stirrer 50, act as irregularities to the microwaves, thereby scattering the microwaves and effectively diffusing them within the thawing chamber R1.

[0044] 2 and 6, the shielding plate 70 has an overhanging portion 70B at the rear of the chamber 20 below the third stirrer 54, so that microwaves reflected by the ceiling wall surface portion 20C are blocked (reflected) at the rear in the front-to-rear direction and are irradiated toward the object to be thawed from the area from the center to the front. In other words, even though the irradiation port 42 is at the rear, the amount of microwave irradiation to the object to be thawed is equalized in the front-to-rear direction.

[0045] Incidentally, the vacuum microwave thawing machine 10 of this embodiment is covered with a cover member 76 to prevent the three stirrers 50, 52, and 54 from coming into contact with the user's hand when inserting their hand into the thawing chamber R1, for example, to put in or take out an item to be thawed. The cover member 76 is made of a microwave-transparent material, such as polypropylene or polyethylene. The cover member 76 is fixed to the shielding plate 70. This reduces the number of components required to attach the shielding plate 70 and the cover member 76 to the chamber 20. Furthermore, when cleaning the thawing chamber R1, the shielding plate 70 and the cover member 76 can be removed together, improving cleaning workability.

[0046] As described above, in the vacuum microwave thawing machine 10 of this embodiment, the antenna 60 of the first stirrer 50 reciprocates across the irradiation port 42, thereby effectively diffusing microwaves immediately after they enter the chamber 20 from the irradiation port 42. Furthermore, the antenna 60 of the first stirrer 50 has a long hole with a length equal to or less than half the wavelength of the microwaves, thereby enabling the microwaves to be diffused and more effectively diffused within the thawing chamber R1. Furthermore, the vacuum microwave thawing machine 10 of this embodiment is provided with a shielding plate 70 having slits 72 with a width equal to or less than half the wavelength of the microwaves, thereby reducing the amount of microwaves that travel directly from the irradiation port 42 to the object to be thawed, thereby preventing uneven heating of the object to be thawed.

[0047] The stirrers 50, 52, and 54 described above have a configuration in which the rotating shaft penetrates the chamber 20, and therefore require a sealing structure around the rotating shaft. The sealing structures of the three stirrers 50, 52, and 54 are similar, and therefore the sealing structure will be described representatively for the third stirrer 54 with reference to Figure 7 (an enlarged view of the main part of Figure 2).

[0048] Third stirrer 54 has a configuration in which rotating antenna 54A and the motor shaft of motor 54B are connected by rotating shaft 54C. Chamber 20 is provided with a holder 80 that holds motor 54B and rotatably holds rotating shaft 54C. Holder 80 includes a holder main body 81 that is fixed to the outer surface (top surface) of chamber 20 and rotatably holds rotating shaft 54C, a cover 82 that covers the top surface of holder main body 81, and a bracket 83 for fixing motor 54B.

[0049] The holder main body 81 is formed with an insertion hole 84 through which the rotating shaft 54C is inserted. The insertion hole 84 has a small-diameter portion 84a with a relatively small inner diameter on the chamber 20 side (lower side) and a large-diameter portion 84b with a relatively large inner diameter on the motor 54B side (upper side). An annular groove 85 is formed in the small-diameter portion 84a, and an O-ring 86 is disposed in the groove 85. An annular oil seal 87 is disposed in the large-diameter portion 84b. The oil seal 87 is pressed from above by a protrusion 82a provided on the cover 82 against a step portion 84c that connects the small-diameter portion 84a and the large-diameter portion 84b of the insertion hole 84.

[0050] With this configuration, the rotating shaft 54C is provided with both the O-ring 86 and the oil seal 87, improving the sealing performance of the chamber 20. Furthermore, because the rotating shaft 54C is supported at two locations, by the O-ring 86 and the oil seal 87, eccentricity of the rotating shaft 54C can be suppressed. This uniformly distributes the forces acting on the surfaces (sliding surfaces) of the O-ring 86 and the oil seal 87 that contact the rotating shaft 54C, preventing partial wear and improving the durability of the O-ring 86 and the oil seal 87.

[0051] Next, the structure of the main body frame 90 constituting the defroster main body 11 will be described with reference to FIG. 8 . The main body frame 90 is composed of a bottom frame 91, a front frame 92, a rear frame 93, a top center frame 94, and a rear center frame 95. The bottom frame 91 forms the outer edge of the bottom surface of the defroster main body 11 and part of the bottom surface. The front frame 92 is generally U-shaped and fixed to the front side of the bottom frame 91, forming both front sides and a top. The rear frame 93, like the front frame 92, is also generally U-shaped and fixed to the rear side of the bottom frame 91, forming both rear sides and a top. The top center frame 94 is arranged to extend in the front-rear direction at the center of the left-right direction on the top surface side, connecting the front frame 92 and the rear frame 93, and functions as a reinforcing member. The rear center frame 95 is disposed at the center of the rear side in the left-right direction, extending in the vertical direction to connect the rear frame 93 and the bottom frame 91, and functions as a reinforcing member.

[0052] At the front side, a front center panel 96 is provided as a decorative panel that forms the portion between the door 12 and the front panel 13. This front center panel 96 also extends vertically and is disposed so as to connect the front frame 92 and the bottom frame 91, and also functions as a reinforcing member. In addition, a chamber frame 97 for fixing the chamber 20 is fixed onto the bottom frame 91.

[0053] Furthermore, a first bracket 98 for mounting the inverter 35 is provided at the upper left corner of the rear frame 93. This first bracket 98 is not only fixed to the top portion 93a of the rear frame 93, but also extends to the left from the portion where the inverter 35 is mounted and is fixed to the left side portion 93b of the rear frame 93. As a result, this first bracket 98 also functions as a reinforcing member for the main body frame 90 that prevents the rear frame 93 from deforming into a diamond shape.

[0054] Furthermore, a second bracket 99 for attaching the control box 36 is provided on the left side of the main body frame 90. The second bracket 99 is a member with an L-shaped cross section that extends in the front-to-rear direction, with one surface fixed to connect the left side portion 92a of the front frame 92 and the left side portion 93a of the rear frame 93, and the other surface extending horizontally to fix the control box 36. This second bracket 99 also functions as a reinforcing member for the main body frame 90 that prevents the front frame 92 and rear frame 93 from tilting in the front-to-rear direction.

[0055] As described above, in the vacuum microwave thawing machine 10 of this embodiment, the number of components constituting the main body frame 90 is reduced due to the presence of the first bracket 98 and the second bracket 99, and costs can be reduced.

[0056] The defroster main body 11 is configured by attaching a plurality of outer panel members to the main body frame 90. As shown in Fig. 9, among these panel members, a bottom panel 100 forming the bottom surface is provided with an intake hole 100a for drawing air into the machine chamber R2. Meanwhile, a left rear panel 102 covering the rear side of the machine chamber R2 is provided with an exhaust hole 102a for exhausting air from the machine chamber R2.

[0057] Specifically, as shown in FIGS. 3 and 4, the magnetron 34 in the machine room R2 is provided with a first center fan 104, which is an air-cooling fan. The first center fan 104 is located above the magnetron 34 and sends air toward the magnetron 34. The magnetron 34 is located near the left rear panel 102, and air passing through the magnetron 34 is exhausted through the exhaust hole 102a. As shown in FIGS. 8 and 10, the inverter 35 is provided with a second center fan 105, which is also an air-cooling fan. The second center fan 105 sends air from the front to the rear of the inverter 35, and air passing through the inverter 35 is exhausted through the exhaust hole 102a. Furthermore, the vacuum pump 30 also has an internal fan and exhausts air through an exhaust port 30a at its rear end, as shown in FIG. 3. That is, air exhausted from the vacuum pump 30 is also exhausted through the exhaust hole 102a. As the air is exhausted, air flows into the machine room R2 through an intake hole 100a provided in the bottom panel 100.

[0058] As shown in FIG. 11 , the air filter 106 can be inserted and removed from the front of the bottom frame 91, and the air filter 106 can be disposed inside (above) the air intake hole 100a. However, if the air filter 106 is not properly maintained or if it is not inserted properly, dust may get into the machine chamber R2. Therefore, to prevent dust from adhering to the circuit board of the inverter 35, an inverter air filter 107 is also disposed in front of the second center fan 105, as shown in FIGS. 4 and 10 . As shown in FIG. 10 , the second center fan 105 is provided with a filter holder 108 that detachably holds the air filter 107. The frame 107a of the air filter 107 is made of elastically deformable resin and can be attached to and detached from the filter holder 108 by bending it. The structure of the filter holder 108 is not limited to this, and it may be configured so that it can be attached and detached from below, or from the left and right.

[0059] Furthermore, the air discharged by the vacuum pump 30 described above contains oil mist. For this reason, a filter capable of absorbing oil is provided inside the vacuum pump 30. However, it is difficult for the filter to completely absorb the oil mist, and the oil mist ends up being discharged to the outside through the exhaust port 30a. If this oil mist spreads within the machine room R2, it could lead to breakdowns in various devices. Therefore, the vacuum microwave thawing machine 10 of this embodiment is provided with an oil collecting member 110 that collects the oil mist discharged from the vacuum pump 30.

[0060] As shown in Figure 12, a shielding plate 112 is provided at the rear lower end of the left side of the chamber frame 97 to block air from flowing into the intake hole 100a located on the right side. This shielding plate 112 is generally L-shaped in top view and extends to near the rear end of the vacuum motor 30. In other words, this shielding plate 112 prevents air discharged from the vacuum pump 30 from flowing forward. The oil collecting member 110 is attached so as to protrude from this shielding plate 112, and is positioned immediately rearward of the exhaust port 30a of the vacuum pump 30.

[0061] As shown in Fig. 13, the oil collection member 110 has a box-like shape that opens forward and is folded upward from the front lower edge, with a reservoir 110a formed at the bottom for collecting oil. In other words, the air discharged from the exhaust port 30a of the vacuum pump 30 first hits the wall 110b, which is the bottom surface of the box-like shape of the oil collection member 110. The oil mist mixed with the air then adheres to the wall 110b and travels along the wall 110b to be collected in the reservoir 110a. Incidentally, the oil collection member 110 can be cleaned, for example, when replacing the filter of the vacuum pump 30.

[0062] <Embodiment 2> Next, a vacuum microwave thawing machine 190 of the second embodiment will be described with reference to Fig. 7. The vacuum microwave thawing machine 190 of the second embodiment has a similar configuration to the vacuum microwave thawing machine 10 of the first embodiment, and therefore the same components are denoted by the same reference numerals as those of the vacuum microwave thawing machine 10 of the first embodiment, and the description thereof will be omitted.

[0063] The vacuum microwave thawing machine 190 of the second embodiment differs from the first embodiment only in the first stirrer that reciprocates in front of the irradiation port 42. As shown in FIG. 14 , the first stirrer 192 in the second embodiment includes a generally rectangular plate-shaped antenna 194 and a linear motor 196 that slides the antenna 194 left and right along the rear wall surface portion 20D. The antenna 194 is reciprocated left and right by the linear motor 196, so that it reciprocates across the irradiation port 42. Therefore, like the vacuum microwave thawing machine 10 of the first embodiment, the vacuum microwave thawing machine 190 of the present embodiment can effectively diffuse microwaves immediately after they enter the chamber 20 from the irradiation port 42. Furthermore, like the first embodiment, the antenna 194 has a plurality of elongated holes 194A formed therethrough, each having a length equal to or shorter than half the wavelength of the microwaves. This allows the microwaves to be diffused and more effectively diffused within the thawing chamber R1.

[0064] <Embodiment 3> Next, a vacuum microwave thawing machine 200 according to a third embodiment will be described with reference to Fig. 15. The vacuum microwave thawing machine 200 according to the third embodiment has a similar configuration to the vacuum microwave thawing machine 10 according to the first embodiment, and therefore the same components are designated by the same reference numerals as those in the vacuum microwave thawing machine 10 according to the first embodiment, and the description thereof will be omitted.

[0065] The vacuum microwave thawing machine 200 of the third embodiment differs from the first embodiment only in the configuration of the shielding material for blocking a portion of the microwaves directed from the irradiation port 42 toward the object to be thawed. In the vacuum microwave thawing machine 10 of the first embodiment, the shielding plate 70 serving as the shielding material is fixed to the cover member 76. In contrast, in the vacuum microwave thawing machine 200 of the third embodiment, the shielding plate 202 serving as the shielding material is not fixed to the cover member 76 but is fixed to the chamber 20 in an upright position behind the cover member 76. Because the shielding plate 202 is fixed to the chamber 20 (e.g., the rear wall surface portion 20D and the bottom surface portion 20E forming the thawing chamber R1), the shielding plate 202 and the chamber 20 are at the same potential, and no discharge occurs between the shielding plate 202 and the chamber 20. Therefore, the vacuum microwave thawing machine 200 of the present embodiment can prevent the object to be thawed from being affected by discharge between the shielding plate 202 and the chamber 20.

[0066] <Embodiment 4> A vacuum microwave thawing machine 210 of embodiment 4, which will be described next, is different from the vacuum microwave thawing machine 10 of embodiment 1 in the configuration of the shielding material, as in embodiment 3. Unlike the vacuum microwave thawing machine 10 of embodiment 1, the vacuum microwave thawing machine 210 of embodiment 4 is not provided with shelf supports 25 for placing trays 24, but is provided with a rack 212 on which multiple trays 24 (four trays 24 in this embodiment) can be set, as shown in Fig. 16. The rack 212 can be inserted into and removed from the chamber 20.

[0067] In the vacuum microwave thawing machine 210 of the fourth embodiment, the shielding material 214 is fixed to the rack 212. More specifically, the rack 212 is a frame-like structure formed in a generally lattice pattern, and as shown in Fig. 16, the shielding material 214 is fixed to pillar members 212A erected at both the left and right ends of the rear of the rack 212. The shielding material 214 is made up of a plurality of plates 216, and these plurality of plates 216 are fixed in a manner that they are placed across a pair of pillar members 212A. The interval between the plurality of plates 216 in the vertical direction is equal to or less than half the wavelength of the microwaves, and the gaps between the plates 216 function as the slits 72 of the shielding plate 70 in the first embodiment.

[0068] The vacuum microwave thawing machine 210 of the fourth embodiment does not require the provision of a member for placing the tray 24 or a member for attaching the shielding material 214 inside the chamber 20, and the chamber 20 has fewer irregularities on the inner wall portion. Therefore, the vacuum microwave thawing machine 210 of the fourth embodiment improves workability when cleaning the inside of the chamber 20 by removing the rack 212 together with the tray 24.

[0069] <Embodiment 5> A vacuum microwave thawing machine 220 of the fifth embodiment, which will be described next, is different from the vacuum microwave thawing machine 10 of the first embodiment in the configuration of the shielding material, as in the third and fourth embodiments. In the vacuum microwave thawing machine 220 of the fifth embodiment, a tray 222 placed on a shelf support 25 is different from the tray 24 shown in the above-described embodiment, and a shielding material 224 is formed by placing this tray 222 on the shelf support 25. More specifically, as shown in FIG. 17 , a plate (an example of a standing wall portion) 226 is fixed to the rear edge of the tray 222 in a manner extending upward. A slit 228 having a width equal to or less than half the wavelength of the microwaves is formed in this plate 226. In addition, when two trays 222 are placed next to each other, the vertical distance between the plates 226 is equal to or less than half the wavelength of the microwaves. That is, in the fifth embodiment, it can be considered that the plates 226 of these trays 222 constitute the shielding material 224, and the gap S between the plates 226 of the two trays 222, together with the slits 228, functions as the slits 72 of the shielding plate 70 in the first embodiment. Therefore, also in the vacuum microwave thawing device 220 of the fifth embodiment, it is possible to reduce the microwaves that are directed directly from the irradiation port 42 toward the object to be thawed, and to suppress uneven heating of the object to be thawed.

[0070] <Other embodiments> The present invention is not limited to the above-described embodiment, and can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. For example, the following embodiments are also included within the technical scope of the present invention.

[0071] In the above-described first and second embodiments, the first stirrer 50, 92 reciprocates in front of the irradiation port 42, and the second stirrer 52 rotates, but the first stirrer may rotate and the second stirrer may reciprocate. Alternatively, both the first stirrer and the second stirrer may reciprocate.

[0072] In the first and second embodiments, the shape and size of the antenna 60, 194 of the reciprocating first stirrer 50, 192 are not limited as long as a part of the antenna 60, 194 crosses the irradiation port .

[0073] In the first and second embodiments, the plurality of elongated holes 66, 194A formed in the antenna 60, 194 of the reciprocating first stirrer 50, 192 are aligned in two mutually perpendicular directions, but this is not limiting. For example, they may be arranged in a staggered pattern or irregularly. Furthermore, although the plurality of elongated holes 66, 194A are all the same size, they may include holes of different sizes.

[0074] In the second embodiment, the first stirrer 192 is configured to slide in the left-right direction, but the direction is not limited thereto. For example, it may slide in the up-down direction, or in a direction inclined up-down, left-right, or right.

[0075] The vacuum microwave thawing machine in the above embodiment has a horizontally elongated shape with the machine chamber R2 located next to the thawing chamber R1, but the machine chamber may also be located below the thawing chamber, making it vertically elongated. [Explanation of symbols]

[0076] 10... Vacuum microwave thawing machine (embodiment 1), R1... Thawing chamber, 20... Chamber, 20D... Rear wall surface portion, 24... Tray (mounting portion), 25... Shelf support, 30... Vacuum pump (pressure reducer), 34... Magnetron (microwave generator), 42... Irradiation port, 50... First stirrer, 66... ​​Long hole, 70... Shielding plate (shielding material), 72... Slit, 76... Cover member, 190... Vacuum microwave thawing machine (embodiment 2), 192... First stirrer, 194A... Long hole, 200... Vacuum microwave thawing machine (embodiment 3), 202... Shielding plate (shielding material), 210... Vacuum microwave thawing machine (embodiment 4), 212... Rack, 214... Shielding material, 220... Vacuum microwave thawing machine (embodiment 5), 222... Tray (mounting portion), 224... Shielding material, 226... Plate (standing wall portion)

Claims

1. a thawing chamber for accommodating an object to be thawed; a pressure reducer for reducing the pressure inside the thawing chamber; a microwave generator that generates microwaves to be irradiated into the thawing chamber; an irradiation port provided in a wall portion forming the thawing chamber and irradiating the microwave toward the thawing chamber; a stirrer for diffusing the microwaves into the thawing chamber; Equipped with The stirrer moves along the wall surface and reciprocates across the irradiation port.

2. 2. The vacuum microwave thawing machine according to claim 1, wherein the stirrer is rotatably provided on the wall surface portion and swings across the irradiation port.

3. The vacuum microwave thawing machine according to claim 1 , wherein the stirrer is provided so as to be slidable along the wall surface portion.

4. The vacuum microwave thawing machine according to any one of claims 1 to 3, wherein the stirrer has a long hole formed therethrough, the long hole having a length equal to or less than half the wavelength of the microwaves.

5. The thawing chamber is provided with a placement section on which the object to be thawed is placed, a shielding material for blocking a part of the microwaves directed from the irradiation port toward the object to be thawed placed on the placement section; 4. The vacuum microwave thawing machine according to claim 1, wherein the shielding material has a slit extending in the horizontal direction and having a width in the up-down direction that is equal to or less than half the wavelength of the microwaves.

6. 6. The vacuum microwave thawing machine according to claim 5, wherein the shielding material is fixed to a wall surface portion that forms the thawing chamber between the irradiation port and the placing portion.

7. a plurality of trays as the placement unit and a rack capable of storing the plurality of trays; The vacuum microwave thawing machine according to claim 5 , wherein the shielding material is fixed to the rack.

8. A cover member is provided to cover the stirrer and is capable of transmitting the microwave, The vacuum microwave thawing machine according to claim 5 , wherein the shielding material is fixed to the cover member.

9. a plurality of trays as the placement unit; The thawing chamber is configured to be able to store a plurality of the trays in a vertically aligned state, The tray has a vertical wall portion extending in a vertical direction at an edge portion on the irradiation port side, 6. The vacuum microwave thawing machine according to claim 5, wherein the slit is formed by a vertical gap between the upright wall portions of two trays arranged vertically and housed in the thawing chamber, the vertical gap having a width equal to or less than half the wavelength of the microwaves, and the upright wall portions of the plurality of trays constitute the shielding material.

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