Vacuum microwave thawing machine

Abstract

To realize a vacuum microwave thawing machine capable of suppressing heating unevenness without providing a rotary table.SOLUTION: A vacuum microwave thawing machine 10 comprises: a microwave generation device 30 that generates microwaves; a chamber 11 that has an incident port 11S5 for the microwaves from the microwave generation device 30, and can accommodate a non-rotary tray on which an item to be thawed is placed; a vacuum pump 20 that reduces pressure inside the chamber 11; a stirrer 35 that is provided on wall parts 11A, 11B of the chamber 11 at a position that does not overlap with the incident port 11S5, and diffuses the microwaves incident from the incident port 11S5 into the chamber 11; and a motor 37 that rotates the stirrer 35.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present technology relates to vacuum microwave thawers. [Background technology]

[0002] Conventionally, vacuum microwave thawing machines are known that irradiate microwaves onto an object to be thawed under a reduced pressure lower than atmospheric pressure to thaw the object, and one example is described in Patent Document 1. The vacuum microwave thawing machine described in Patent Document 1 includes a chamber that houses the object to be thawed, a vacuum pump that reduces the pressure inside the chamber, a pressure regulating valve that restores the pressure inside the chamber, and a microwave generator that irradiates microwaves into the chamber. The vacuum microwave thawing machine irradiates microwaves while repeatedly performing a depressurization process and a pressure restoration process, thereby heating and thawing the object to be thawed. A turntable that rotates around a rotation axis is provided inside the chamber, and the object to be thawed is placed on this 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] By using the above-mentioned turntable, microwaves can be more easily applied uniformly to the items to be thawed, preventing uneven heating during thawing. However, since the items to be thawed cannot be placed anywhere other than on the turntable, the amount of thawing is limited. This poses a problem when thawing a large amount of items for commercial use, etc., resulting in increased thawing times and time. Furthermore, since a circular turntable is placed inside a rectangular chamber, the corners of the chamber are wasted space where the turntable is not located. This wasted space increases the time required for decompression and requires a large, high-performance vacuum pump, which is the decompression means.

[0005] The present technology was developed based on the above-mentioned circumstances, and aims to realize a vacuum microwave thawing machine that can suppress uneven heating without providing a rotating table. [Means for solving the problem]

[0006] The vacuum microwave thawing machine related to the present technology includes a microwave generating device that generates microwaves, a chamber that has an entrance port for microwaves from the microwave generating device and is capable of accommodating a non-rotating tray on which an item to be thawed is placed, a vacuum pump that reduces the pressure inside the chamber, a stirrer that is provided in a wall of the chamber at a position that does not overlap with the entrance port and that diffuses the microwaves that are entered from the entrance port into the chamber, and a motor that rotates the stirrer.

[0007] The inlet may be provided in a first side wall of the chamber, and the stirrer may be provided in a portion of the first side wall other than the inlet and in a ceiling wall.

[0008] The chamber may also include a shelf support portion that accommodates multiple tiers of the trays in the vertical direction, and the shelf support portion may be provided on a second side wall portion of the chamber that is different from the first side wall portion. [Effects of the Invention]

[0009] According to the present technology, a vacuum microwave thawing machine that can suppress uneven heating can be realized without providing a turntable. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view of a vacuum microwave thawing device according to a first embodiment. [Figure 2] A perspective view of the chamber, shelf support, and regulating valve. [Figure 3] Cross section of line III-III in Figure 1 [Figure 4] Cross section of line IV-IV in Figure 1 [Figure 5] Cross section of line VV in Figure 4 [Figure 6] Cross section of Figure 1 along line VI-VI [Figure 7] Enlarged cross-sectional view of the microwave entrance DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment 1> A vacuum microwave thawing machine 10 according to the first embodiment will be described with reference to Fig. 1 to Fig. 7. The symbols F, B, L, R, U, and D shown in each figure respectively indicate the front and rear in the front-rear direction of the vacuum microwave thawing machine 10, the left and right in the width direction (left-right direction) when viewed from the front, and the top and bottom in the vertical direction (up-down direction).

[0012] The vacuum microwave thawing machine 10 includes a chamber 11 that accommodates an object to be thawed, and thaws the object in the chamber 11, which has been depressurized to a vacuum state, by irradiating it with microwaves. As shown in Figures 1 to 6, the vacuum microwave thawing machine 10 roughly includes the chamber 11, a swing door 12, a vacuum pump 20 for depressurizing the chamber 11, a first adjusting valve 22 and a second adjusting valve 23 for restoring (increasing) the pressure in the chamber 11, a vacuum sensor 28 for measuring the pressure (degree of vacuum) in the chamber 11, a magnetron 30 (an example of a microwave generating device) for generating microwaves, a waveguide 31 for guiding the microwaves from the magnetron 30 into the chamber 11, a control device 60, and an operation unit 65.

[0013] The control device 60 includes at least a microcomputer and a memory, and controls the operation of the vacuum microwave thawing device 10 based on a control program. The operation unit 65 is provided so that the user can change various settings of the vacuum microwave thawing device 10 and select an operation mode.

[0014] 2, chamber 11 is a horizontally elongated, approximately rectangular box made of metal such as stainless steel, and its interior serves as a thawing chamber for storing and removing the object to be thawed. Chamber 11 has a front opening 11S1 for storing and removing the object to be thawed, and front opening 11S1 can be opened and closed by door 12.

[0015] Shelf supports 40 are provided within the chamber 11 to accommodate trays (shelf boards) on which to place the items to be thawed. The shelf supports 40 are provided in pairs on the left side wall 11C and the right side wall 11D (an example of a second side wall) of the chamber 11. A plurality of pairs of shelf supports 40 (six in this embodiment) are provided at intervals in the vertical direction, allowing multiple tiers of trays to be accommodated in the vertical direction within the chamber 11. Note that the shelf supports 40 are omitted from FIGS. 3 and 4.

[0016] As shown in Fig. 6, the shelf support 40 according to this embodiment is made of a wire member such as stainless steel, and protrudes from each of the side walls 11C and 11D into the chamber 11 in a U-shape in plan view. In addition, a reinforcing wire member may be provided along the left-right direction to connect the pair of U-shaped wire members (see the uppermost shelf support 40 in Figs. 5 and 6).

[0017] 2, an intake port 11S2 is provided in the ceiling wall portion 11B of the chamber 11, and the intake port 11S2 is connected to a pipe 21 of a vacuum pump 20 as shown in Fig. 5. The air inside the chamber 11 is sucked into the vacuum pump 20 from the intake port 11S2 through the pipe 21.

[0018] As shown in Fig. 2, a pipe 25 connected to the first adjustment valve 22 and the second adjustment valve 23 is connected to the left side wall 11C of the chamber 11, and as shown in Fig. 4, an inlet 11S3 is provided through which outside air flows in via the pipe 25. The left side wall 11C also has a sensor mounting port 11S4 to which a mounting pipe for a vacuum sensor 28 is connected. As shown in Fig. 5, a microwave inlet 11S5 is provided at the center in the vertical and horizontal directions of the rear wall 11A (an example of a first side wall) of the chamber 11. A waveguide 31 is connected to the inlet 11S5 via a cover 32, which will be described later, as shown in Fig. 7.

[0019] The first adjusting valve 22 and the second adjusting valve 23 are solenoid valves whose opening and closing is controlled by the control device 60, and are configured to allow outside air to flow into the chamber 11. As will be described later, the first adjusting valve 22 is provided to finely adjust the pressure in the chamber 11 during the thawing operation. The second adjusting valve 23 is provided to allow outside air to flow in all at once after the thawing is completed, etc., to return the pressure in the chamber 11 to atmospheric pressure. As shown in FIG. 2, the first adjusting valve 22 and the second adjusting valve 23 are provided in a form branching off from a pipe 25 connected to the inlet 11S3 of the chamber 11. The first adjusting valve 22 and the second adjusting valve 23 are each equipped with a silencer 29 to reduce noise and vibration caused by the inflow of outside air.

[0020] As shown in Figure 3, the magnetron 30 is disposed at the rear left of the chamber 11. The magnetron 30 generates microwaves by applying a high voltage between two poles, a cathode and an anode, while a magnetic field is applied. A metallic waveguide 31 is connected to the exit port of the magnetron 30, and the microwaves from the magnetron 30 propagate along the waveguide 31. The waveguide 31 extends in the left-right direction at the rear of the chamber 11, connecting the magnetron 30 to an entrance port 11S5 of the rear wall portion 11A of the chamber 11.

[0021] As shown in Fig. 7, a lid 32 is provided between the tip opening 31A of the waveguide 31 on the chamber 11 side and the inlet 11S5 of the chamber 11. The lid 32 is sized and shaped to cover the inlet 11S5. The lid 32 is made of a material that is transparent to microwaves but can block the passage of gas, such as glass. By providing the lid 32, it becomes possible to evacuate the chamber 11 and maintain the vacuum state while allowing microwaves to enter the chamber 11 from the inlet 11S5.

[0022] As shown in FIGS. 3 to 6, the chamber 11 is also provided with a stirrer 35 for diffusing microwaves within the chamber, and a motor 37 for rotating the stirrer 35. In this embodiment, a plurality of (three) stirrers 35 are provided, with one motor 37 provided for each stirrer 35. The stirrers 35 are made of metal blades, and in this embodiment, are approximately X-shaped in plan view. The intersection of the approximately X-shaped stirrers 35 is connected to the rotation shaft of the motor 37, and the stirrers 35 are rotated by driving the motor 37. The microwaves are reflected by the rotating stirrers 35 and diffused within the chamber 11.

[0023] The stirrers 35 include a first stirrer 35A and a second stirrer 35B provided on the inner surface of the rear wall 11A of the chamber 11 (the surface facing the internal space of the chamber 11), and a third stirrer 35C provided on the inner surface of the top wall 11B. The first stirrer 35A and the second stirrer 35B are provided on the rear wall 11A at positions that do not overlap with the microwave entrance port 11S5. More specifically, the first stirrer 35A and the second stirrer 35B are provided at the lower left and upper right parts of the rear wall 11A, respectively, and are arranged in opposing positions across the entrance port 11S5. As shown in FIG. 6, the first stirrer 35A and the second stirrer 35B are arranged at a predetermined distance G1 from the shelf support 40 so as not to come into contact with the thawed food. The third stirrer 35C is provided at a central position in the front-to-rear and left-to-right directions on the top wall 11B.

[0024] By arranging multiple stirrers 35 in such positions, microwaves are incident on chamber 11 without being blocked by stirrers 35. Furthermore, even when items to be thawed are placed on multiple trays lined up in upper and lower tiers, microwaves tend to be diffused uniformly to the items to be thawed on each tray.

[0025] On the other hand, it is preferable not to provide a stirrer 35 on the bottom wall 11E of the chamber 11. The bottom wall 11E is easily soiled by objects falling from the tray, and so not providing a stirrer 35 makes cleaning easier.

[0026] The motors 37 include a first motor 37A for the first stirrer 35A, a second motor 37B for the second stirrer 35B, and a third motor 37C for the third stirrer 35C. The first motor 37A and the second motor 37B are provided on the outer surface of the rear wall 11A of the chamber 11 (the surface opposite the internal space of the chamber 11) behind the first stirrer 35A and the second stirrer 35B, respectively. The third motor 37C is provided on the outer surface of the top wall 11B of the chamber 11, above the third stirrer 35C.

[0027] Next, the operational control of the vacuum microwave thawing machine 10 configured as described above will be explained. The control device 60 calculates the microwave irradiation time based on the weight of the item to be thawed input by the user through the operation unit 65. It also calculates the reference finishing pressure based on the finishing temperature of thawing input through the operation unit 65. Then, when the item to be thawed is placed inside and the door 12 is closed, and an instruction to start operation is given from the operation unit 65 (the start switch is pressed), the vacuum pump 20 is operated to start depressurizing the chamber 11. At this start, both the first adjustment valve 22 and the second adjustment valve 23 remain in the closed state.

[0028] When the control device 60 determines that the pressure inside the chamber 11 has decreased to a predetermined pressure value based on the detection result of the vacuum sensor 28, it continues to reduce the pressure for a first predetermined time, and opens the first adjustment valve 22 after the first predetermined time has elapsed (first adjustment valve opening step). As a result, the pressure inside the chamber 11 increases slightly, but the pressure inside the chamber 11 becomes a vacuum state lower than atmospheric pressure.

[0029] When a second predetermined time has elapsed after opening the first adjustment valve, the control device 60 energizes the magnetron 30 to activate the magnetron 30 (magnetron ON step). The control device 60 also activates the motor 37 to rotate the stirrer 35. As a result, the microwaves generated by the magnetron 30 pass through the waveguide 31 and enter the chamber 11 from the entrance port 11S5. The microwaves entering from the entrance port 11S5 diffuse within the chamber 11, as shown by the arrows in FIGS. 3 and 4, and are reflected by the inner surfaces of the chamber 11 and door 12 and the stirrer 35, and are then diffused within the chamber 11.

[0030] By diffusing microwaves within chamber 11 in this way, the microwaves are uniformly irradiated onto the object to be thawed, making it easier for the temperature of the object to be thawed to rise evenly. Also, the vacuum (reduced pressure) causes the ice or frost contained in the object to vaporize all at once, cooling the surface of the object, while the microwaves vibrate the water molecules inside the object, heating the object. As a result, rapid thawing is possible while suppressing deterioration in the quality of the object to be thawed (for example, deterioration in texture and taste and discoloration due to cell destruction of the food material).

[0031] When a third predetermined time has elapsed after energizing magnetron 30, control device 60 closes first adjustment valve 22 to reduce the pressure inside chamber 11 again (first adjustment valve closing step). Furthermore, when a fourth predetermined time has elapsed after closing first adjustment valve 22, control device 60 cuts off the energization of magnetron 30 to stop the operation of magnetron 30 (magnetron OFF step).

[0032] The control device 60 repeats the above-mentioned first adjusting valve opening process, magnetron ON process, first adjusting valve closing process, and magnetron OFF process based on the pre-calculated microwave irradiation time, finishing pressure, etc. Then, when the control device 60 determines that thawing is complete, it opens the second adjusting valve 23 after the magnetron OFF process to return the inside of the chamber 11 to the atmosphere. This allows the door 12 to be opened and the thawed food to be removed.

[0033] As described above, the vacuum microwave thawing machine 10 includes the chamber 11 having the microwave entrance port 11S5 and capable of accommodating a non-rotating tray on which the object to be thawed is placed, the stirrer 35 for diffusing the microwaves entered through the entrance port 11S5 into the chamber 11, and the motor 37 for rotating the stirrer 35. The stirrer 35 is provided in the wall portions 11A and 11B of the chamber 11 at a position that does not overlap with the entrance port 11S5.

[0034] In this way, microwaves incident from entrance port 11S5 are diffused within chamber 11 by stirrer 35, which is rotated by motor 37. Stirrer 35 is provided at a position that does not overlap entrance port 11S5, and does not prevent microwaves from entering chamber 11. As a result, uneven heating can be easily suppressed even when the tray on which the object to be thawed is placed is a non-rotating type.

[0035] Furthermore, by using non-rotating trays, the tray shape is not limited to circular shapes, and trays of a shape and size that matches the internal space of chamber 11 can be used. As a result, the storage capacity of the thawed items can be increased, and the number of thawings and the thawing time can be reduced even when thawing a large amount of items for commercial use, etc. On the other hand, when there is no need to increase the storage capacity compared to conventional methods, chamber 11 can be made smaller, which reduces the installation space, shortens the decompression time, and enables the vacuum pump to be made smaller.

[0036] The inlet 11S5 is provided in the rear wall 11A of the chamber 11, and the stirrers 35 (35A, 35B, 35C) are provided in the rear wall 11A in a portion other than the inlet 11S5 and in the ceiling wall 11B.

[0037] In this way, the stirrers 35A and 35B and the inlet 11S5 can be provided on the same first side wall (rear wall 11A), thereby reducing the space required for their installation. Also, by providing the stirrer 35C on the ceiling wall 11B, the microwaves can be diffused more uniformly.

[0038] The chamber 11 also has a shelf support portion 40 that can accommodate multiple tiers of trays in the vertical direction, and the shelf support portion 40 is provided on a second side wall portion (left side wall portion 11C, right side wall portion 11D) of the chamber 11 that is different from the first side wall portion (rear wall portion 11A).

[0039] In this way, the shelf supports 40 can accommodate multiple trays, further increasing the capacity of the items to be thawed. Furthermore, by providing the shelf supports 40 on the second side wall (left side wall 11C, right side wall 11D) separate from the first side wall (rear wall 11A) on which the stirrers 35A, 35B and the entrance port 11S5 are provided, the items to be thawed on the trays are less likely to come into contact with the stirrers 35A, 35B. As a result, the stirrers 35A, 35B can effectively diffuse the microwaves within the chamber.

[0040] <Other embodiments> The present technology is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included in the technical scope of the present technology.

[0041] (1) The shape and size of the chamber 11, and the shape, size, and arrangement of the shelf support 40 and the stirrer 35 are not limited to those shown in the drawings, and can be changed as appropriate according to the specifications. [Explanation of symbols]

[0042] 10: Vacuum microwave thawing machine, 11: Chamber, 11A: Rear wall (first side wall), 11B: Ceiling wall, 11C: Left side wall (second side wall), 11D: Right side wall (second side wall), 11S5: Inlet, 20: Vacuum pump, 30: Microwave generator, 35, 35A, 35B, 35C: Stirrer, 37: Motor, 40: Shelf support

Claims

1. a microwave generating device that generates microwaves; a chamber having an entrance port for microwaves from the microwave generating device and capable of accommodating a non-rotating tray on which an object to be thawed is placed; a vacuum pump that reduces the pressure inside the chamber; a stirrer provided on a wall portion of the chamber at a position not overlapping with the entrance port, the stirrer diffusing the microwaves incident from the entrance port into the chamber; A vacuum microwave thawing machine comprising: a motor that rotates the stirrer.

2. the inlet is provided in a first sidewall of the chamber; 2. The vacuum microwave thawing machine according to claim 1, wherein the stirrer is provided on a portion of the first side wall other than the entrance and on a ceiling wall.

3. the chamber includes a shelf support portion that accommodates the trays in a plurality of stages in the vertical direction; The vacuum microwave thawing machine according to claim 2 , wherein the shelf support is provided on a second side wall portion of the chamber that is different from the first side wall portion.

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