JP2003226577A - Far infrared low temperature dryer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently dry materials to be dried by indirectly heating wood ceramic capable of emitting the wavelength of far infrared ray having excellent drying efficiency to emit the far infrared ray. <P>SOLUTION: The materials to be dried are arranged on a wire mesh of a food tray 26 placed on a food shelf. Power is applied to an electric heater 38 arranged on the back surface of a wood ceramic panel 37 to heat. The wood ceramic panel 37 is heated by the heat of the heater 38 to emit infrared ray containing far infrared ray. The materials to be dried which are placed on the food tray 26 start to be dried by the infrared ray. In drying, a fan motor 9 is driven and inside air is stirred by a fan 8 to uniformalize the temperature and humidity of the inside air to eliminate the drying unevenness of the materials to be dried. The air present in the inside 6 of a casing 2 and containing moisture is discharged through a damper 11 by intermittently driving a blower 10 rotatably. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a far-infrared low-temperature dryer for drying foods and the like with far-infrared rays. More specifically, the present invention relates to a far-infrared low-temperature dryer that indirectly heats wood ceramics that is a porous carbon material and uses it as a far-infrared radiator to dry foods and the like.

[0002]

2. Description of the Related Art Many methods for drying fish by far infrared rays have been proposed. The drying efficiency by far infrared rays is determined by the temperature range tested (17 to 22 ° C, 19 to 25 ° C, 27 to 3 ° C).
Far infrared drying is higher than warm air drying in any temperature range of 4 ° C.), and it takes 15 to 20 hours or more to dry with warm air. It is reported that the time has been shortened (Chiba Prefectural Fisheries Experimental Station Research Report, No.49, 55-62 (1991)).

In Japanese Unexamined Patent Publication No. 07-132197 and Japanese Unexamined Patent Publication No. 2001-112644, a sheet heating element made of plate-like carbon fiber is used as a heating element to emit far infrared rays for thawing and drying food. Something to use is suggested. The former sheet-like non-heating element uses carbon fiber mixed paper radiating far infrared rays, and an electric current is passed through the paper to generate heat.

The method for heating the carbon fiber mixed paper is a method of causing an electric current to flow through the carbon fibers in the carbon fiber mixed paper, that is, the Joule heat generated by the electric resistance of the conductor when the current flows in the conductor is Due to the non-uniform distribution of carbon fibers, stable heating cannot be achieved and temperature control is difficult. In addition, this carbon fiber-mixed paper is a mixture of carbon fiber and pulp, and since the proportion of carbon fiber is small, it cannot emit far infrared rays in the wavelength region most efficient for thawing and drying. Since the latter carbon fiber heating element also applies current to generate heat, it is unavoidable that current locally flows due to the current flowing through the carbon fiber, and a stable planar heating element cannot be obtained. It is difficult to control the temperature.
Further, since the dryer using the far infrared rays has a special structure, there is a problem that new investment is required.

A plant fiber such as wood or bamboo is used as a raw material, and a crushed piece obtained by crushing these or a cut piece cut is impregnated with a phenol resin to obtain 400 to 2000 in a non-oxidizing atmosphere.
Wood ceramics that are fired and carbonized at ℃ are known (Japanese Patent No. 2552577, Japanese Patent No. 3008095, etc.). The infrared radiation intensity of this wood ceramics is
Strictly speaking, it depends on the material of wood ceramics,
Close to a black body, the spectral radiant intensity has a peak near 5 μm,
It has a characteristic of decreasing in a region where the wavelength is longer than this. Therefore, since radiation of wavelengths in the far infrared region is also efficiently emitted, far infrared rays can be efficiently emitted by using wood ceramics.

[0006]

However, even if a current is directly applied to the wood ceramics, the current locally flows and the planar wood ceramics cannot be uniformly heated.

The present invention has been made based on the above technical background, and achieves the following objects. An object of the present invention is to provide a far-infrared low-temperature dryer that stably radiates far-infrared rays from wood ceramics by indirect heating to dry an object to be dried. Another object of the present invention is to provide a far-infrared low-temperature dryer equipped with wood ceramics that can easily control temperature and can efficiently radiate far-infrared rays. It is still another object of the present invention to provide a far infrared low temperature dryer provided with wood ceramics capable of emitting a far infrared wavelength in a region having a good drying efficiency for drying an object to be dried. Still another object of the present invention is to provide a far infrared low temperature dryer that can efficiently radiate far infrared rays only by installing wood ceramics and a panel that radiate far infrared rays in a conventional electric heat dryer.

[0008]

The present invention adopts the following means in order to achieve the above object. The far infrared low temperature dryer of the present invention includes a housing having a substantially closed drying space,
400 ~ under a non-oxidizing atmosphere, which is placed in the housing, and mixed with a carbonized product of the plant fiber material and a thermosetting resin.
It is composed of wood ceramics fired and carbonized at 2000 ° C. and heating means for indirectly heating the wood ceramics.

The wood ceramics may be in the form of a plate that is obtained by mixing the carbide and the thermosetting resin and firing the mixture under pressure. When a plate-shaped material is fired, distortion is generated. Therefore, in order to prevent this, it is preferable to pressurize and fire. This pressurization is preferably 0.04 MPa / cm ² or less.

The plant fiber material is preferably crushed bamboo. The thermosetting resin is preferably a phenol resin. The heating means is one in which a linear heating wire is arranged on the back surface of the plate, and the temperature inside the housing that radiates far infrared rays may be controlled to 30 ° C to 60 ° C. In particular,
It is ideal for drying foods that require low temperature drying.

If warm air blowing means for blowing warm air is arranged in the housing, both warm air and far infrared rays are effective.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described. FIG. 1 is a front view showing an embodiment of a far infrared low temperature dryer of the present invention, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a front view showing a state in which a door is removed. The housing 2 constitutes the main body of the far infrared low temperature dryer 1. The housing 2 is hollow and has a rectangular box shape, and one surface thereof is open. The inner surface 3 and the outer surface 4 of the housing 2 are made of stainless steel plates. A heat insulating material such as rock wool is interposed and arranged in the intermediate layer between the inner surface 3 and the outer surface 4.

A front panel 5 for controlling the far-infrared low-temperature dryer 1 is arranged above the front surface of the housing 2.
A control switch, a thermometer, and the like are arranged on the front panel 5. A fan 8 is arranged on an upper portion 7 of the inside 6 of the housing 2. The fan 8 is rotationally driven by a fan motor 9 arranged on the top of the housing 2. Fan 8
Is for agitating the air in the interior 6 to make the temperature and humidity of the air in the interior 6 uniform. A part of the air in the inside 6 of the housing 2 is discharged to the outside by the blower 10 via the damper 11.

The same amount of air as the air in the interior 6 of the housing 2 discharged to the outside is supplied with fresh outside air from the air supply port 12 in which the filter is arranged. At this time, a stainless tube (not shown) is arranged on the back side of the far infrared radiation panel 35 described later. Warm fresh air is passed through this to warm it, and the hot air outlet 3 is placed at the bottom of the interior 6 as warm air.
Eject from 1.

A door 15 is arranged on the front surface of the housing 2, and one end of the door 15 is openably and closably supported by the housing 2 by a hinge 16. The door 15 is made of a stainless steel plate on the front surface and the back surface,
A heat insulating material is arranged between them. At one end of the door 15,
A handle 17 is provided. The handle 17 has a door 1 on the housing 2.
One end of 5 is fixed. When the door 15 is opened, the handle 17 is pulled by the hand and opened. Since the structure and function of the handle 17 are well known and are not the subject of the present invention, they will not be described in detail here.

Four casters 21 are arranged on the lower surface 20 of the housing 2. The casters 21 are provided for moving the far infrared low temperature dryer 1.
A food shelf 25 is housed in the inside 6 of the housing 2. The food shelf 25 is a shelf for placing a food tray 26 on which food is placed on the shelf 27. The food shelf 25 is a shelf that improves the circulation of air and is composed of only a frame having an L-shaped cross section.

The food tray 26 is made of a rectangular frame with an open top, and the bottom is made of wire mesh to facilitate air circulation. The food tray 26 is taken out of the shelf 27 and dried on the wire net of the food tray 26 such as fish, seaweed and other marine products, marine products, livestock products, smoked products,
Place dried products such as agricultural products such as vegetables and fruits and processed agricultural products on a flat surface so that they do not overlap.

The food tray 26 is placed on the shelf 27 and dried. The temperature of the inside 6 of the housing 2 is maintained at 30 to 60 ° C., and drying is performed at this temperature. The normal operating temperature is designed on the assumption that the food is dried at a temperature of about 50 ° C. in consideration of the far infrared emissivity of wood ceramics described later. Three side walls 3 of the inside 6 of the housing 2
0, that is, both side wall surfaces 30 when viewed from the front except the door 15 side,
Two far-infrared far-infrared radiation panels 35 are arranged and fixed in two steps on the inner wall surface.

However, if the material to be dried is placed in this gap between the upper two steps, the radiation of infrared rays and far infrared rays may not be sufficient, so that the drying may not be sufficient. Therefore, the material to be dried is not arranged at this height position, or the far infrared radiation panel 35 is arranged so as to fill the gap between the far infrared radiation panels 35, and the material to be dried is arranged at this position. It may be a structure.

[Far Infrared Radiation Panel 35] FIG. 5 (a) is a front view of the far infrared radiation panel 35, FIG. 5 (b) is a plan view of FIG. 5 (a), and FIG. 5 (c). FIG. 6 is a back view of FIG. Frame 36 of far infrared radiation panel 35
Is a frame made of an aluminum material having an L-shaped cross section. On the frame 36, three wood ceramics panels 37 are arranged side by side on a plane. The wood-ceramic panel 37 is made of plant fibers such as wood, bamboo, and pulp, and crushed pieces obtained by crushing these or cutting pieces are impregnated with phenol resin by a natural impregnation method or under reduced pressure for a predetermined time, 400-200 under oxidizing atmosphere
It is a wood ceramic which is fired and carbonized while being pressed (0.04 MPa / cm ² or less) at 0 ° C. (see, for example, Japanese Patent Nos. 2552577 and 3008095).

On the back surface of the wood ceramics panel 37, an electric heater 38, which is meandering in a U shape, is arranged. The electric heater 38 is fixed to the back surface of the wood ceramics panel 37 with screws 40 by two electric heater fixing hardware 39. The electric heater 38 can be supplied with necessary electric power from the power supply 41.

(Operation of Embodiment) Next, a method of using the first embodiment will be described. Fish, seaweed and other marine products to be dried on the wire net of the food tray 26, processed marine products,
Place dried products such as livestock products, smoked products, agricultural products such as vegetables and fruits, and processed agricultural products on a flat surface so that they do not overlap. The door 15 is closed, and the electric heater 38 arranged on the back surface of the wood ceramics panel 37 is turned on to generate heat.

Due to the heat generated by the electric heater 38, the surface temperature of the wood ceramics panel 37 is heated to about 50 ° C., and infrared rays including far infrared rays are emitted. The infrared radiant intensity of this wood ceramics has a characteristic that the spectral radiant intensity has a peak in the vicinity of 5 μm, and has a characteristic that the spectral radiant intensity gradually decreases in a region having a longer wavelength.

In the case of water, there are absorption peaks at wavelengths of 3 μm (stretching vibration of OH group) and 6 μm (bending vibration of OH group), and most substances have a large absorption region in the range of 2.5 μm to 25 μm. Yes, because it matches the wavelength range of wood ceramics, a high heating effect is obtained by wood ceramics. That is, the water in the material to be dried can be heated, and the material to be dried itself can be heated.

The infrared rays cause the material to be dried placed on the food tray 26 to start drying. At the time of this drying, the fan motor 9 is started, and the air in the interior 6 is agitated by the fan 8 to make the temperature and humidity of the air in the interior 6 uniform and to eliminate the unevenness of drying of the material to be dried. The air containing moisture in the inside 6 of the housing 2 is discharged to the outside via the damper 11 by the blower 10 which is intermittently driven to rotate.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The specifications of the far infrared low temperature dryer 1 described above are shown below. 1. Size of wood ceramics panel 37 ... 300 mm
× 300 mm × 10 mm This manufacturing method is as follows. In this example, the wood-ceramics panel 37 is made of Moso bamboo, which is a crushed piece or a cut piece (10
(0 mm × 42 mm × 6-10 mm) is carbonized by a conventional method, and the carbonized product is mixed with a powdered phenol resin (SHONOL BRP-120Z (trademark) manufactured by Showa High Polymer Co., Ltd.) (carbonized bamboo: (Phenol resin = 10: 1 (weight ratio)), which is formed into a plate shape and is carbonized by firing at 700 ° C. under pressure (0.01 MPa / cm ² or less) in a non-oxidizing atmosphere. This pressure panel is disclosed in Japanese Patent No. 3008.
It may be made by the manufacturing method disclosed in No. 095. 2. Internal 6 size ... Height 1000mm x Width 950mm x
Depth 1030 mm (capacity 0.95 m ³ ) 3. Temperature inside the wood ceramics panel 37 ... approx. 5
0 ° C 4. Electric power consumption of the electric heater 38 (one panel) ... 70
0W (plus minus 10%) 5. Food shelf 25 ... Vertical 750 mm x Horizontal 900 mm x Depth 1000 mm Distance between upper and lower shelves 300 mm, 2 shelves for each stage (approximately 450 mm
(About 1000 mm) (Experimental example) The far infrared low temperature dryer 1 of the above-described example was subjected to the following performance test. As shown in FIG. 6, in order to confirm the effect of heat rays including far infrared rays radiated from the wood ceramics panel 37, an experiment was conducted with the wood ceramics panel 37 arranged in the upper and lower two stages arranged in the inner surface removed. It was One radish was placed at 6 positions on the food shelf 25 arranged in the far infrared low temperature dryer 1, that is, at each position to measure the water content. The following Table 1 shows the results.

[0027]

[Table 1]

There was a difference in the weight reduction rate between the test piece placed at the position and the test piece placed at the position. The reason for this is presumed to be that the position is an intermediate position between the upper and lower wood ceramics panels 37, the position where the stainless steel plate is attached, and there are few heat rays containing far infrared rays. There was a large difference in the water content between the test pieces at different positions. The reason for this is that the warm air outlet 31 is arranged near the position, and therefore it is presumed that the combined use of far infrared rays and warm air has a great effect on the change of the water content.

This is because there is a large difference between the positions having the same height, or there is no difference in the water content of the test pieces at different positions even if the heights are different. Presumed. With respect to the water content at the same height and position as the wood ceramics panel 37 arranged on the upper stage, the water content at the position close to the wood ceramics panel 37 has a low water content, so it is presumed to be the drying effect by the far infrared rays. On the other hand, since there is almost no difference in the water content of the test piece arranged at the position where the wood ceramics panel 37 is not arranged and the water content of the test piece arranged at the position, the drying effect by far infrared rays is indirectly estimated.

Next, the power consumption was measured as follows for comparison.

[Table 2]

The amount of electric power used in Table 2 is a hot air circulation type incubator commercially available as an example and a comparative example of the present invention, with the load of the material to be dried placed inside being constant, as a comparative example. The electric power consumption of each of the three electrothermal drying devices from which all the wood ceramics panels 37 of this embodiment are removed is shown. The maximum power consumption of the embodiment of the present invention is 700 W (10% of the program) for one far-infrared radiation panel 35, and the maximum power consumption for a total of 6 sheets is 4.8 KVA. The maximum power consumption of the thermostat of the comparative example is 5.0 KVA. The electrothermal drying device obtained by removing all the wood ceramics panels 37 except the electric heater 38 from the embodiment of the present invention has the same maximum power consumption as that of the embodiment of the present invention. Although the electric power consumption of the embodiment of the present invention is smaller than that of a thermostat of a type that circulates warm air, it has been found that it is not much different from that of an electrothermal drying device in which only the wood ceramics panel 37 is removed.

FIG. 7 shows the apple drying data showing the dried state of the apples over time, and shows the time change from the start of drying to 24 hours after the inside temperature is set to 50 ° C.
It is measured by the rate of change of weight. In the table of FIG. 7, "far infrared rays", "warm air" (general-purpose incubator), and "temperature" (electrothermal drying device) are the examples of the present invention described above.
Warm air general-purpose incubator and wood ceramics panel 37
It means an electrothermal drying device from which is removed. In the case of one whole apple, there is no substantial difference between the above three dryers.

However, "far infrared" after 24 hours
Observing the apples dried in, the discoloration progressed from the center, but the apples dried in a warm air type general-purpose incubator were generally discolored, but the discoloration in the center was small.
That is, it was observed that the "far-infrared" type was heated from the center because the degree of discoloration means the evolution of dryness.

Similarly, when the same experiment was carried out with a raw egg, the white egg of the raw egg dried by "far infrared rays" after 24 hours had changed from transparent to white. It was heated in a container and the white of raw egg showed almost no change. The apples cut to a thickness of 5 to 10 mm have substantially the same final drying time, but it can be understood that they are quickly dried by a general-purpose incubator that is dried with warm air.

The reason for this is presumably because the apples are forcibly dried from both sides with warm air, so that in the case of a thin apple, the drying is accelerated even if the apple core is not dried. However, an apple thicker than 15 to 20 mm occurs from an early stage of drying by the far infrared low temperature dryer 1 of the embodiment of the present invention. As described above, since the wavelength range of water in the apple and the wavelength range of the wood ceramics coincide with each other, a high heating effect can be obtained by the wood ceramics. If drying progresses, this effect will not occur and it is estimated that there is not much difference from other drying means.

From the above results, the far-infrared low-temperature dryer using wood ceramics, which is an embodiment of the present invention, is most suitable for drying foods with thick wall thickness and foods with high water content at the initial stage. I can say that.

[Other Embodiments] In the above-mentioned embodiments, the object to be dried such as food is not dried with warm air. However, as is clear from the above experiment,
At the outlet of the warm air, the material to be dried is characterized by quick drying. Therefore, it may be a dryer that uses both the radiation of the far infrared rays and the warm air. That is, it is possible to apply warm air to the material to be dried and simultaneously radiate far infrared rays efficiently.

[0038]

As described in detail above, the far-infrared dryer of the present invention is capable of stably emitting far-infrared rays from wood ceramics to dry an object to be dried, easy temperature control, and far-infrared rays. It has the effect of being able to radiate efficiently, and to radiate the wavelength of far-infrared rays in the region where the material to be dried has a good drying efficiency. Further, since the structure is similar to that of the conventional electric heat dryer, it can be diverted from the electric heat dryer, so that there is an effect that the cost can be suppressed.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a far infrared low temperature dryer of the present invention.

FIG. 2 is a right side view of FIG.

FIG. 3 is a front view showing a state in which a door is removed.

FIG. 4 is a front view of a food shelf.

5 (a) is a front view of a far infrared radiation panel, FIG. 5 (b) is a plan view of FIG. 5 (a), and FIG.
FIG. 5C is a rear view of FIG.

FIG. 6 is a front view of a far-infrared low-temperature dryer that has been subjected to a performance test.

FIG. 7 is data showing the dry condition of apples over time.

[Explanation of symbols]

1 ... Far infrared low temperature dryer 2 ... Case 5 ... Front panel 8 ... fan 10 ... Blower 15 ... Door 17 ... Toride 25 ... food shelf 26 ... Food tray 27 ... Shelf 35 ... Far infrared radiation panel 37 ... Wood ceramics panel 38 ... Electric heater

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 3/10 H05B 3/14 G 3/14 3/20 356 3/20 356 C04B 35/52 D (72) Inventor Toshimi Akaishi 172-2 F term, Iwasaki-cho, Iwaki-cho, Nakatsugaru-gun, Aomori Prefecture 3-2 (F) (reference) 3K034 AA12 AA22 BB06 BB14 BC05 BC12 JA01 3K092 PP20 QA05 QB26 QB45 RF03 RF11 RF19 RF22 VV22 3L113 AA01 AB02 AC08 BA17 CB06 BA18 BA16 BA18 BA27 BA18 BA27 LR07 LT05 4G032 AA14 AA57 BA04 GA12

Claims (6)

[Claims] 1. A housing having a substantially closed dry space, and a carbonized material obtained by carbonizing the plant fiber material and a thermosetting resin, which are arranged in the housing and mixed with each other.
Wood ceramics that are fired and carbonized at 0 to 2000 ° C,
A far-infrared low-temperature dryer comprising a heating means for indirectly heating the wood ceramics. 2. The far-infrared low-temperature dryer according to claim 1, wherein the wood ceramics is a plate-shaped product obtained by mixing the carbide and the thermosetting resin and firing the mixture under pressure. Far infrared low temperature dryer. 3. The far infrared low temperature dryer according to claim 1, wherein the plant fiber material is obtained by crushing bamboo. 4. The far infrared low temperature dryer according to claim 1 or 2, wherein the thermosetting resin is a phenol resin. 5. The heating means according to claim 1, wherein the heating means has a linear heating wire arranged on the back surface of the plate, and the temperature in the housing for radiating far infrared rays is 30 ° C. to 60 ° C. Far-infrared low temperature dryer characterized by being controlled at ℃. 6. The far-infrared low-temperature dryer according to claim 1, wherein warm air blowing means for blowing warm air is arranged in the housing.