JPH0454875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a grain drying apparatus for drying grain under reduced pressure in a constant constant temperature state.

Conventional technology Conventionally, as a method for forced drying of materials to be dried,
Hot air conduction drying using hot air, radiation heat transfer drying using infrared rays, far infrared rays, etc., and high frequency heat transfer drying using high frequency waves are well known. All of these methods are heat-dependent drying methods that use heat to promote the vaporization of moisture within the material to be dried. On the other hand, drying methods such as vacuum drying and freeze drying are also known in which water is removed by reducing the vapor pressure of water by creating a vacuum atmosphere.
Furthermore, there is also a method of drying by heating and reducing pressure using a fan that exhausts air while generating heat, as described in, for example, Japanese Patent Laid-Open No. 57-19582. Further, as a drying apparatus for grains, etc. by the above-mentioned method of drying by heating and reducing pressure, for example, JP-A-59
A device has been proposed in which a hollow chamber having a decompression frictional heat generating mechanism and a granule storage chamber are formed so as to be ventilated, as described in Japanese Patent No. 18344.

Problems to be Solved by the Invention The conventional heat-dependent drying method described above removes moisture by heat of evaporation, so it
It requires 539.8 cal of heat of vaporization, requires a large heat source, and has the disadvantage of high running costs. Further, heat-dependent drying methods have problems not only in drying efficiency but also in drying finish. That is, it is difficult to uniformly dry the inside and surface of the article to be dried;
Overdrying of the surface or heating may cause structural changes and the surface may harden.

Furthermore, although vacuum drying and freeze drying methods have relatively high drying efficiency, they are currently only used for drying special products because the equipment is expensive and the cost is high. In addition, conventional equipment that uses a fan to heat and reduce pressure to dry while emitting heat will heat up to over 40°C if the vacuum is maintained during drying in the summer, and if you try to lower the temperature, the degree of vacuum will increase. This method cannot be satisfactorily applied to the drying of grains, which requires drying at a relatively low temperature. Furthermore, with conventional drying apparatuses in which granular articles such as grains are dried in a stationary state within a drying chamber, sufficient ventilation is not provided between the grains, making it impossible to dry them satisfactorily.

The present invention was devised in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a grain drying device that has good drying efficiency and drying finish, is inexpensive in running cost, and is easy to operate. This is the purpose.

Means for Solving the Problems Technical means for solving the above problems will be explained based on drawings corresponding to embodiments.

The present invention employs a method of providing two systems for heat source and exhaust in the drying chamber 1, which is constructed of heat insulating material and pressure-resistant material. That is, the heat source uses the cooling and heating device 9,
Exhaust is performed by the exhaust device 3, and a certain amount of outside air is introduced from the inlet in order to maintain a constant degree of pressure reduction. Furthermore, a rotatable grain container 12 made of ventilation material such as a mesh material and a blower 11 are installed in the drying chamber 1 to keep the inside of the drying chamber in a constant constant temperature state and a constant reduced pressure state, and to rotate the grain inside the grain container. I dried it under reduced pressure while moving it around.

Effect: Grain to be dried is placed in the container 12 in the drying chamber.
When the drying chamber is set up and the power is turned on, the pressure inside the drying chamber is reduced by the exhaust device 3, but once the pressure reaches a certain degree, it is maintained in that state as it balances out with the air from the outside air inlet. Further, the interior of the room is maintained at a constant temperature by a cooling/heating device 9. Grain container 1
As the grains in the container move inside the container, water is moved to the surface by the reduced pressure, and the water film on the surface is scattered by the blower 11 into the indoor atmosphere. The exhaust device dehumidifies the room and always acts to reduce the humidity in the room.
Drying is carried out continuously, efficiently and uniformly.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a schematic side sectional view showing an embodiment of a grain drying apparatus according to the present invention, and FIG. 2 is a side view of a grain container thereof.

In the figure, reference numeral 1 denotes a drying chamber, which is comprised of a casing 2 made of a pressure-resistant material that can withstand reduced pressure and is filled with a heat insulating material. Reference numeral 3 denotes an exhaust fan which is an exhaust device provided outside the housing 2 facing the internal exhaust port 4 formed in the housing 2, and the exhaust air from the exhaust fan passes through the heat exchanger 8. Then, it is discharged to the outside air from the external exhaust port 5. Note that a vacuum pump may be used as the exhaust device. On the other hand, 7 is an external intake port, and the outside air taken in through the external intake port passes through a heat exchanger 8 as shown in the figure, and is taken into the drying chamber 1 through the internal intake port 6. Therefore, heat is exchanged between the intake and exhaust air in the drying chamber in the heat exchanger according to the temperature difference, so there is little energy loss, and the outside air is drawn into the drying chamber at a temperature close to the temperature inside the drying chamber.

Reference numeral 9 denotes a heating/cooling device for keeping the inside of the drying chamber at a constant constant temperature, and any device capable of dissipating and absorbing heat may be used, such as a heat pump type cooling/heating device or a combination of a heater and a refrigeration device. 10 indicates a heat radiation or heat absorption port of the heating device. Reference numeral 11 denotes a blower installed in the drying chamber, which diffuses the air in the room and applies a constant amount of air to the grain container, which will be described later, to scatter a film of water, which is a fluid film, that has moved onto the surface of the object to be dried.

Reference numeral 12 denotes a grain drying container, which is installed in the drying chamber via mounting legs 14 so as to be able to rotate intermittently. As shown in FIG. 2, the grain drying container is constructed by arranging a plurality of individual containers in which a hopper 16a, a hopper 16b, and a moving path 17 connecting and communicating the two hoppers are integrally formed. And the hopper opening of the grain drying container is
The container is covered with lids 18 and 19 that can be opened and closed so that grains can be taken in and out of the container. Further, the hopper and passage section of the container are made of a net-like material or a breathable porous material, so that the air from the blower 12 directly hits the grains in the container. Note that 19 is a ventilation space provided between the moving paths 17;
3 is a rotating shaft of the grain drying container, and 15 is
This is a rotating motor, and is intermittently rotated by a control device (not shown).

With the above structure, when grains are put into one hopper 16a of the grain drying container 12, the grains naturally fall through the movement path 17 and move to the lower hopper 16b. When the movement is completed, an appropriate control device acts to control the rotational drive motor 1.
5 is activated to invert the grain drying container 12 and repeat the above-described operation thereafter. On the other hand, inside the drying chamber 1, the pressure is reduced to a certain level due to the operation of the exhaust fan 3, and the temperature is maintained at a certain constant temperature by the cooling/heating device, so the water inside the grain moves to the surface of the grain due to the reduced pressure. . The moisture that has moved to the surface of the grain enters through the net-like material and is scattered by the air from the blower 11 passing through the ventilation space 19 during the movement, thereby uniformly drying the grain.

Using the device of the above example, the exhaust fan for reducing pressure was operated at 1.5kw output, and 800mmAq was generated.
Maintain a reduced pressure of , and keep the drying room at a constant temperature of 20°C.
Dry 50 kg of rice in 10 hours. As a result, the scent,
It was possible to obtain high quality rice with excellent color and taste.

In the apparatus of the above embodiment, the cooling/heating device 9 was installed at the top of the housing 2 to radiate or absorb heat directly into the drying chamber, but the cooling/heating device was installed at the external intake port 7 of the heat exchanger 8. It's okay. In addition, this device
It goes without saying that it is suitable not only for drying grains but also for drying granular articles.

Effects Since the present invention is configured as described above, it has the following remarkable effects.

(b) Since it is drying under reduced pressure, it does not require a large heat source, and the inside of the drying chamber can be arbitrarily set to the appropriate temperature for drying the material to be dried using a cooling/heating device, resulting in outstanding drying efficiency and a significant reduction in running costs. This allows us to produce dried grains of unparalleled quality.

(b) Grain is placed in a rotatable grain container made of ventilation material, and the grain is dried while moving within the container, so that the grain can be dried evenly and efficiently.

(c) Since the film of water that has moved to the surface of the grain is efficiently scattered by the blower and continuously dehumidified by the exhaust device, uniform drying is performed continuously.

(d) The device is simple and easy to operate, and it is safe because it does not require a large heat source.

(e) By providing a heat exchanger, heat is exchanged between the exhaust air and the intake air, reducing energy loss and further increasing the energy saving effect.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of one embodiment of the grain drying apparatus according to the present invention, and FIG. 2 is a side view of the grain container thereof. 1: Drying room, 2: Housing, 3: Exhaust device, 4: Internal exhaust port, 5: External exhaust port, 6: Internal intake port,
7: External intake port, 8: Heat exchanger, 9: Cooling/heating device,
11: Blower, 12: Grain drying container, 16a, 1
6b: hopper, 17: mover.

Claims (1)

[Claims] 1. A drying chamber configured with heat insulating material and pressure-resistant material, and the amount of air exhausted and intake within the time period from when the air in the drying chamber is exhausted until the air reaches a constant pressure. a rotatable grain container installed in the drying chamber and made of ventilation material such as a mesh material; A grain drying device comprising a blower installed in a drying chamber and a heating and cooling device that maintains the inside of the drying chamber at a constant temperature, and drying grain under reduced pressure at a constant constant temperature. 2. The grain drying apparatus according to claim 1, wherein the grain container is constituted by a connected body of two hoppers. 3. The grain drying apparatus according to claim 1 or 2, wherein the air intake and exhaust into the drying chamber is performed through a heat exchange device installed outside the drying chamber. 4. The grain drying apparatus according to claim 1, 2 or 3, wherein the exhaust device is a blower fan. 5. The grain drying apparatus according to claim 1, 2 or 3, wherein the exhaust device is a vacuum pump.