JP4374512B2 - Hot air dryer - Google Patents

Description

[0001]
[Industrial application fields]
The present invention is a vegetable residue that is currently an industrial waste of the food industry, for example, okara produced from a tofu factory, red beans / bean curd produced from a brewing factory, sake lees produced from a sake factory, The present invention relates to a dryer for drying soy sauce cake produced from a soy sauce factory.
[0002]
[Prior art]
As for the above-mentioned vegetable residue, what is reused as a food material and feed is still small, and the fact is that many are discarded. This has recently been related to the problem of waste disposal that has been highlighted as a cause of environmental degradation, and there is an increasing movement in this industry to reduce the amount of waste through recycling. Based on this situation, when looking at conventional dryers that dry plant residues and reuse them in food materials and feeds, there are many expensive and large-sized ones, and it can not be profitable unless it is a food factory that processes a large amount, At present, small and medium-sized factories are disposed of after paying treatment fees. The reason for this high price and large size is that the conventional drying method is rotary drying and airflow drying using inertia classification, so it is difficult to downsize, and plant residues are susceptible to oxidative corrosion Therefore, it is necessary to equip the means for reducing the contact time with oxygen as much as possible, for example, equipment that is directly connected to the vegetable residue production outlet at the terminal of the production line of the food factory and is processed in synchronization with the speed of the production line. It becomes expensive. As a specific example, a rotating stirring crusher / dryer is equipped with a stirring blade in a cylindrical drying chamber, and is stirred and pulverized and dried by sending hot air of 500 ° C to 550 ° C. In order to synchronize with the above, it is necessary to lengthen the stirring portion, which becomes large and expensive. In addition, since it is treated with high-temperature hot air, the dried product is easily burnt, and pulverization performed with a stirring blade has a problem in quality such as variation in particle size, and its application is limited. In the hot air flow drying method, as shown in JP-A-6-105663, a dry air pulverization is carried out in a drying chamber in which a cylinder is laid down horizontally and blown right above the cylindrical drying chamber. , Using the inertia classification method to take out only those having a particle size suitable for food material from the uppermost take-out port, using the fact that the dry matter is raised by the air flow bundle and the particle size becomes higher as the particle size becomes higher Therefore, when obtaining a dried product having a particle size suitable for a food material, the height of the dryer cannot be changed even when the amount of the processed material to be dried is small, and the size cannot be reduced. Furthermore, since both machines are common, the machine is large, so it is often impossible to install it in an empty space on an existing production line, and a separate transport line for direct connection must be provided.
[0003]
[Problems to be solved by the invention]
In the current situation where the waste disposal problem is becoming a major social problem as described above, it is expensive to recycle vegetable residues that are susceptible to oxidative spoilage as food materials and feed in conventional dryers. It will be large, and it will not be profitable unless it is a food factory that produces a large amount of plant residues. For this reason, in small and medium-sized food factories including private businesses that cannot introduce expensive and large dryers, processing is requested from industrial waste disposal companies, but the processing costs tend to increase year by year. A dryer is desired.
[0004]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems, an air-flow dryer using a centrifugal classification system different from the conventional drying system is made possible to reduce the size and the price. The dryer according to the present invention includes a hot-air generator 6 and a drying chamber 13 connected via a hot-air supply path 8 so that hot air 25 can be supplied along a tangent to the inner wall of the cylindrical portion of the drying chamber 13, and includes an object receiving target 10. The drying object supply path 12 is connected to the cylindrical portion 27 of the drying chamber 13, and a drying chamber 14 communicating with the drying chamber 13 is provided in the upper portion of the drying chamber 13, and the upper end of the drying chamber 14 is recovered through the discharge pipe 17. The drying chambers 13 and 14 are connected to a cyclone 48 as an apparatus, and the drying chambers 13 and 14 are formed by concentrating the cylindrical portion and the upper and lower portions of the cylindrical portion in a conical shape. A medium ball 22 having a diameter of 1 mm to 10 mm and a medium ball having a diameter of 15 mm to 25 mm for urging the rotation of the pulverized and dried medium ball to prevent the material to be dried from accumulating on the bottom of the drying chamber. For speed control and quality maintenance Characterized by comprising a control device capable of performing temperature control of.
[0005]
In the dryer configured as described above, hot air 25 is supplied along the tangent to the inner wall of the cylindrical portion in the drying chamber 13 to generate a spirally rising airflow bundle 23, and the airflow bundle 23 and the eddy current 24 generated around the medium are used as a medium. The material to be dried 9 supplied from the material to be dried supply path 8 is pulverized while rolling and rotating the balls 22 along the inner walls of the drying chambers 13 and 14. In parallel with this, the object to be dried 9 is dried by convection heat transfer from the hot air 25 and conduction heat transfer from the medium balls 22 and the drying chambers 13 and 14, and against the gravity of the powdered particles and the centrifugal force Due to the balance between the centripetal force, the direction of the air flow bundle and the wind force, heavy objects with large particle diameters gather below the drying chamber and are further finely crushed by the media balls. Only the dried product having the required particle size is sent to the cyclone 18 through the discharge pipe 17 connected to the upper end of the drying chamber 14 and separated into the exhaust air 32 and the dried product 20 by the action of the cyclone. The At this time, in accordance with the properties of the material 9 to be dried, the wind speed of the hot air 25 is set to an appropriate speed of 10 m / sec to 50 m / sec, and the inclination of the conical portion 31 formed at the upper part of the drying chamber 14 is 30 ° to 30 °. By setting an appropriate angle of 60 °, the processing speed and the particle size of the dried product to be taken out can be freely changed. Further, by lowering the positions where the conical portions 28 and 31 are formed and shortening the cylindrical portions 27 and 30, the contact between the medium ball 22 and the material to be dried 9 can be made dense, and the grinding efficiency is increased, so the particle size is uniform and of good quality. As a result, the dryer was downsized and the price was reduced.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described in detail with reference to the drawings. This example shows an example of a dryer for drying okara produced by a tofu manufacturer. Okara components to be dried are 22.7% protein and 15.5 lipids by dry matter weight ratio. %, Fiber 17.8%, sugar 40%, ash 4%, and moisture content 85%. 1 and 2, a propane gas cylinder 2 and a gas burner 4 are connected by a gas pipe 33, a proportional valve 3 is provided at an arbitrary position of the gas pipe, and an automatic ignition mechanism and a gas leakage countermeasure mechanism not shown are provided. The hot air generator 6 configured to send the hot air 25 by the blower 5 and the drying chamber 13 are connected by the hot air supply path 8. The drying chamber 13 and the hot air supply path 8 are connected so that hot air 25 is supplied along a tangent to the inner wall 15 of the drying chamber cylindrical portion, and the hot air supply path 8 is provided with a temperature sensor 7 for detecting the temperature of the hot air. To do. A to-be-dried object supply port 12 is connected to an upper portion of a portion where the drying chamber 13 and the hot air supply path 8 are connected, and a to-be-dried object receiving port 8 is provided at the upper end of the to-be-dried object supply path 12. A rotary feeder 11 is provided. At the portion where the hot air supply path 8 and the material to be dried supply path 12 are connected in the drying chamber 13, a backing plate 34 is provided so as to guard the supply port of the hot air 25 and the material 9 to be dried, and the medium ball 22 has the hot air 25. In addition to preventing the wind direction from being disturbed by hitting the supply port of the object to be dried 9, the supplied object 9 to be dried is easily diffused into the hot air 25. The drying chambers 13 and 14 are formed of cylindrical portions 27 and 30 and portions 26, 28, 29, and 31 whose upper and lower ends are constricted in a conical shape. Limit the size. A drying chamber 14 is formed in communication with the upper portion of the drying chamber 13, a temperature sensor 16 is attached to the drying chamber 14, and a medium ball 22 is disposed in the drying chamber 13. The upper end of the drying chamber 14 and the cyclone 18 are connected by a discharge pipe 17, and an exhaust pipe 19 is provided in the upper part of the cyclone 18.
[0007]
The control device 21 is provided with an inverter and a temperature control unit of a temperature sensor, and the hot air temperature, the drying state temperature, and the air volume (air speed) can be set according to the composition and moisture content of the object to be dried. The speed of the rotary feeder 11 can be set according to the vegetable residue production speed to come out. These set values are obtained through experiments. In the case of this example, the temperature of the hot air is 330 ° C. to 340 ° C., and the dry state temperature during drying when obtaining a dried product having a water content of 8% to 10% is determined. The temperature was 83 ° C to 85 ° C, and the wind speed was 25 m / sec to 27 m / sec. Moreover, since the vegetable residue production speed | velocity which comes out from a small and medium-sized food factory is 80 kg / hour-90 kg / hour, the speed | rate of a rotary feeder is set according to it. Further, the proportional valve 3 and the temperature sensor 7 connected to the control device 21 can maintain the temperature of the hot air sent to the drying chamber at the temperature set by the control device 21 regardless of fluctuations in the outside air temperature, starting time, and overheating. The proportional valve 3 is operated by the difference between the hot air temperature detected by the temperature sensor 7 and the temperature set by the control device 21 to adjust the gas supply amount to the gas burner 4. The temperature sensor 16 connected to the control device is for controlling the drying state temperature so as to be maintained at the temperature set by the control device 21. The temperature detected by the temperature sensor 16 and the temperature set by the control device are The proportional valve 3 is operated based on the difference between the two to adjust the gas supply amount to the gas burner 4. This dry state temperature control has priority over the hot air temperature control.
[0008]
The flow of hot air and the material to be dried and centrifugal classification will be described with reference to FIGS. The hot air 25 supplied from the hot air supply path 8 to the drying chamber 13 is supplied from the tangential direction of the inner wall of the cylindrical portion 27 of the drying chamber 13 and becomes an airflow bundle 23 in a spiral shape along the inner walls of the drying chambers 13 and 14. Ascend to the exit 36 of the drying chamber 14. As shown in FIG. 4, a vortex 24 is generated inside the spirally rising airflow bundle 23, and the pressure in the central portion 35 of the vortex 24 is reduced. This situation is particularly conspicuous near the hot air inlet, and as it approaches the vicinity of the outlet 36, the air flow bundle 23 is collapsed and equalized, resulting in a laminar flow 37 toward the outlet 36. Further, a downward flow 38 is generated toward a portion where the pressure in the central portion 35 of the vortex 24 is low. Accordingly, when the material to be dried 9 is supplied into the drying chamber 13, the following centrifugal classification is performed. When an object to be dried 9 is supplied into the drying chamber 13 from an object supply path 12 provided above the hot air supply path 8, it is captured by the air flow bundle 23 and pulverized by the medium balls and the inner walls of the drying chambers 13 and 14. However, a large mass of weight is pushed against the inner wall of the drying chamber 13 by centrifugal force and stalls and falls downward, or reaches a thin portion of the airflow bundle 23 and falls along the downward flow 38 in the center. . The fallen thing is again captured by the airflow bundle 23 and is repeatedly pulverized by the medium balls and the inner walls of the drying chambers 13 and 14, and the mass of the material 9 to be dried is pulverized and dried to become powder and become the product level. Only the particles having a particle size rise by the air flow bundle 23 and are discharged from the outlet 38.
[0009]
The configuration of the drying chamber will be described with reference to FIGS. The drying chamber 13 is formed by a cylindrical portion 27 and portions 26 and 28 in which the upper and lower ends of the cylindrical portion 27 are conically constricted. The drying chamber 14 formed in communication with the drying chamber 13 is connected to the cylindrical portion 30. The upper and lower ends of the cylindrical portion 30 are formed by conical portions 29 and 31. The shape and function of the conical portions 26, 27, 28, 31 will be described below. The conical constricted portions 26 and 29 are formed so that the object to be dried does not accumulate at the corners by forming an inclination with respect to the cylindrical portions 27 and 30 at 45 ° in the case of the present embodiment. The conical constricted portion 28 is inclined with respect to the cylindrical portion 27 by 50 ° in the case of the present embodiment, whereby the medium balls 22-a, 22-b arranged in the drying chamber 13 (FIG. 7). And a relatively large lump to-be-dried object 9 does not rise above conical constricted portion 28, and limits the size of an object passing through conical constricted portion 28. Thus, the contact between the medium ball 22 and the material 9 to be dried can be made dense, so that the grinding and drying efficiency can be increased. More specifically, the medium balls 22-a, 22-b and the object to be dried 9 are trapped by the spirally rising airflow bundle 23 and rotate up in the drying chamber 13, so that centrifugal force is applied to them. Since the centripetal force due to gravity and the gravity force due to its own weight and the ascending force due to the air flow bundle 23 work and rise and fall with the balance of force, if the balance of the force at the constricted portion 28 is made downward, It will not rise above that. That is, when looking at the direction of the force at the constricted portion 28, the centripetal force due to the centrifugal force is perpendicular to the conical surface and is downward with respect to the horizontal plane. By appropriately changing the inclination of the conical surface so that the downward force becomes larger than the ascending force by the air flow bundle 25, it can be prevented from rising above the conical constricted portion 28. It should be noted that the relatively large mass to be dried that could not be prevented by the constricted portion 28 falls along the downward flow as described in the flow of the hot air and the material to be dried. It is pulverized or stays in the drying chamber 14 and pulverized and dried.
[0010]
The conical constricted portion 31 is inclined with respect to the cylindrical portion 30 at 50 ° in the case of the present embodiment, so that the media balls 22-c, 22-d (FIG. 7) disposed in the drying chamber 14 are formed. And the dried product 9 that has not reached the dry level as a product is prevented from rising above the conical constricted portion 31 on the same principle as the conical constricted portion 28, By restricting the size of the object passing through the narrowed portion 31, the contact between the medium balls 22-c, 22-d and the object to be dried 9 can be made dense, so that the pulverization drying efficiency can be increased.
[0011]
The medium ball 22 will be described with reference to FIGS. In FIG. 7, the generic name of the medium ball is 22, and the description will be made in the order of 22-a, 22-b, 22-c, and 22-d in order from heavy to light. A medium ball 22 made of a highly wear-resistant material such as ceramic disposed in the drying chambers 13 and 14 is used as a pulverized drying medium, and the balance between the wind force of the airflow bundle 23 and the weight and centrifugal force of the medium ball 22. As a result, the heavier one 22-a is rotated in the drying chambers 13 and 14 in order of 22-b, 22-c, and 22-d in order of increasing weight, and comes into contact with the object 9 to be dried. The medium ball 22 is pulverized by rolling on the inner wall of the drying chamber, and at the same time, the medium ball 22 is dried by the heat of the air flow bundle 23 and the conduction heat transfer of the medium ball 22. The trajectory of the rotation of the medium ball 22 is similar to the trajectory of the vortex 24 in FIG. 4 and rotates as shown in FIG. In addition, since the airflow bundle 23 rotates in a spiral manner and the medium balls 22 having different weights rotate at different heights, the drying chamber 13, as shown in FIG. Since the inside of 14 rotates evenly, pulverization is performed efficiently. Also, the smaller the diameter of the medium ball, the smaller the particle size to be crushed. Therefore, when the material to be dried is supplied during the movement of the medium ball as described above, the large volume of material to be dried just supplied into the drying chamber 13. Is pulverized relatively large with heavy media balls with a large diameter, and gradually pulverized with small media balls with a light weight and small diameter as it rises gradually. A dry product can be obtained efficiently. In the case of this example, 4 to 5 balls having a diameter of 25 mm and 200 to 250 balls having a diameter of 8 mm, 4 mm, and 2 mm were disposed in the drying chamber.
[0013]
In the above-described embodiment, an example of using a hot air device using propane gas is shown, but the present invention is not limited to this, and a hot air device using electricity, oil, or the like may be used.
[0014]
Moreover, in the said Example, although the drying room was piled up in 2 steps | paragraphs, it can be set as 1 to several steps | paragraphs depending on the property of the to-be-dried object, and the processing amount.
[0015]
Further, in the above embodiment, the slopes of the conical constricted portions 26 and 29 of the drying chambers 13 and 14 are set to 45 °, and the conical constricted portions 28 and 31 are inclined to 50 °. Even if it changes, if it is a vegetable residue, the same function as the said Example will be obtained if it selects and sets in the range of 30 degrees-60 degrees with the component and moisture content.
[0016]
Moreover, in the said Example, although the diameter of the medium ball | bowl 22-a was 25 mm, even if the component of the vegetable residue which is a to-be-dried substance and a moisture content change, if it sets and sets in the range of 15 mm-25 mm, it will be with the said Example. The same function is obtained.
[0017]
In the above example, the hot air temperature was 330 ° C. to 340 ° C., the dry state temperature was 83 ° C. to 85 ° C., and the wind speed was 25 m / sec to 27 m / sec. Even if it changes, the same function as the above-mentioned embodiment can be obtained by selectively setting the hot air temperature in the range of 300 ° C. to 350 ° C., the dry state temperature in the range of 80 ° C. to 85 ° C., and the wind speed in the range of 10 m / sec to 50 m / sec.
[0018]
Moreover, in the said Example, although the rotary feeder 11 was used as a conveyance means of to-be-dried material, other conveyance means, such as a screw, may be sufficient.
[0019]
In addition, although an incidental configuration such as providing a cleaning inspection door or inspection window in the drying chambers 13 and 14 or covering the outside with a heat insulating material is not shown, it is configured not to depart from the intended scope of the present invention. You can freely change the design if you want to.
[0020]
【The invention's effect】
As described above, the present invention constructs a centrifugal classification type airflow dryer for drying plant residues, arranges a medium ball for pulverization drying in the drying chamber, and constricts the conical shape in the drying chamber. The size of the material to be dried and the medium ball that passes through the portion can be restricted, so that the contact between the material to be dried and the medium ball per unit volume can be made dense, and the crushing and drying efficiency can be improved. As a result, it has become possible to reduce the cost together with downsizing of the device.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an air dryer using hot air for drying plant residues. FIG. 2 is a view taken along arrow AA in FIG. 1. FIG. Explanatory drawing about the flow of dry matter and centrifugal classification [FIG. 4] BB view of FIG. 3 [FIG. 5] D section enlarged view of FIG. 3 [FIG. 6] E section enlarged view of FIG. FIG. 8 is a cross-sectional view taken along the line CC of FIG. 7. FIG. 9 is a supplementary explanatory diagram of FIG. 8.
DESCRIPTION OF SYMBOLS 1 Airflow dryer 20 Dry matter 2 Gas cylinder 21 Control apparatus 3 Proportional valve 22 Media ball 4 Gas burner 23 Airflow bundle 5 Blower 24 Eddy current 6 Hot air generator 25 Hot air 7 Temperature sensor 26 Conical constricted part 8 Hot air supply path 27 Cylinder Part 9 To-be-dried part 28 Conical-squeezed part 10 To-be-dried object receptacle 29 Conical-squeezed part 11 Rotary feeder 30 Cylindrical part 12 To-be-dried object supply path 31 Conical-squeezed part 13 Drying chamber 32 Exhaust air 14 Drying room 33 Gas pipe 15 Cylindrical inner wall 16 Temperature sensor 35 Centrifugal center part 17 Discharge pipe 36 Outlet 18 Cyclone 37 Laminar flow 19 Exhaust pipe 38 Flow downward

Claims (4)

A hot-air generator equipped with means capable of changing the air volume, wind speed, and heat quantity and a cylindrical drying chamber are provided, and the cylindrical drying chamber is formed by concentrating the upper and lower parts into a conical shape in multiple stages. The hot air supply device and the drying chamber are connected to the portion near the bottom of the drying chamber so that hot air is supplied along the tangent to the inner wall of the drying chamber cylinder, and the exhaust pipe is connected in a conical shape at the top. Introduce plant residue along with hot air supplied from the bottom of the drying chamber, raise it while swirling along the cylindrical drying chamber wall surface, and take out the plant residue that has become dry and fine powder together with the exhaust from the upper stack Centrifugal classification plant residue drying device. The centrifugal classification type plant residue dryer which made the inclination of the part restrict | squeezed conically in the drying chamber of Claim 1 30 degrees-60 degrees with respect to the cylindrical part. A centrifugal classification type vegetable residue drier in which the drying chamber of claim 1 is connected in one stage to multiple stages. A pulverized drying medium ball having a diameter of 1 mm to 10 mm is disposed in the drying chamber according to claim 1, 2, 3, the rotation of the pulverized drying medium ball is urged, and a mass of the material to be dried at the bottom of the drying chamber is pulverized. Centrifugal classification plant residue drying apparatus provided with a powder drying medium ball having a diameter of 15 mm to 25 mm to prevent accumulation.

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