JPS6142181B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for drying grains stored in a drying chamber over a considerable thickness in a stationary state by blowing circulating drying air on them. The present invention relates to a method for uniformly drying grains, which can dry all stored grains to a uniform finished moisture content by eliminating the drying difference between the side and the exhaust side.

In general, if the drying process is continued by blowing dry hot air on grains stored at a certain stacking height in a drying room under a static state, the grains facing the side where the dry hot air is blown will be On the other hand, grains facing the ventilation side are exposed to humid air that has absorbed the evaporated moisture on the ventilation side, and drying does not proceed as quickly as possible. There is a difference in the degree of dryness of the grains between the ventilation side and the ventilation side, and it is not possible to dry all the grains uniformly. The above phenomenon increases in proportion to the height of the grain pile.

Therefore, when drying grains under a stationary condition, it is necessary to control the accumulated layer to such an extent that no difference in drying occurs.

However, if the grains are restricted to the above-mentioned sedimentary layer, a large amount of drying facilities and labor will be required to uniformly dry a large amount of grain, which is practically impossible.

Therefore, the inventor of the present invention discovered that during stationary drying work, when grains are exposed to drying air, the moisture in the grains is evaporated, and the drying air discharged from the grain layer absorbs moisture and becomes humid air.

When moist air is applied to grains that have been dried to a certain extent, the dried grains absorb moisture from the humid air through a hygroscopic reaction phenomenon, increasing the moisture content of the grains themselves.

It was thought that if this method was applied, it would be possible to dry all the grains, even if they were piled up over a considerable height under static conditions, to a uniform finished moisture content.

In view of the above, the present invention has been developed by drying the grains stacked in a drying chamber in a stationary state by blowing circulating drying air at approximately 20°C to 30°C, and then drying the grains by the drying action of the circulating drying air. When the facing grain approaches the final finished moisture content, instead of the circulating drying wind, humid room temperature air is circulated and continuously showered on the grain, so that all the grains have a uniform finished moisture content regardless of the pile height. The present invention provides a method for uniformly drying grains that can be dried in a manner similar to that of the present invention, and the construction of an apparatus using the method of the present invention will be described below with reference to a preferred embodiment shown in the accompanying drawings.

In the drawing, reference numeral 1 denotes a drying chamber surrounded by wall plates 2, and inside the drying chamber 1, a drying chamber 3 and a circulation chamber 4 are installed.
The upper part of the drying chamber 3 is connected to the upper part of the drying chamber 3, and the lower part of the drying chamber 3 is connected to a ventilation chamber 5 provided through a ventilation flat plate 6 installed at the bottom of the drying chamber 3. The above circulation chamber 4
An air blower 7 for circulation is disposed inside, and a heat pump 8 for generating dry hot air or humid normal temperature air is installed below the air blower 7. The heat pump 8 is composed of a compressor 9, a condenser 10, a liquid receiving tank 11, an expansion valve 12, and an evaporator 13. They are installed separately. The compressor 9 and the condenser 10 are connected via a high-pressure gas pipe 14, the condenser 10 and the liquid receiving tank 11 are connected by a connecting pipe 15, and the liquid receiving tank 11 is equipped with an expansion valve 12. The evaporator 13 is connected via a pipe 16 to the compressor 9 via an absorption pipe 17, thereby forming a constant circulation path. Reference numeral 18 denotes a moisture content detector for measuring the moisture content of the upper layer of grain stored in the drying chamber 3 in a static state. It is connected to machine 9. Note that the moisture content detector 18 may be provided in the middle layer. 20 is a dehydration pipe attached to the bottom of the circulation chamber 4.

Although not shown in the drawings, the drying chamber 1 described above is of course provided with a loading and unloading device for loading and unloading grains into and out of the drying chamber 3.

Next, the method of the present invention will be explained.

Now, using a suitable loading device (not shown), grains with a high moisture content, for example, about 26%, are stacked and stored in the drying chamber 3 under a static condition so that a predetermined piled layer is formed. Next, the circulation blower 7 is started and the heat pump 8 is operated at the same time. Then, the high pressure gas compressed by the compressor 9 is sent to the condenser 10,
Here, the air is cooled and condensed heat is radiated, and this thermal energy warms the air flowing in the circulation chamber 4 to generate dry air. Then, the gas in the condenser 10 is deprived of condensation heat and becomes a liquid, and after being returned to the liquid receiving tank 11, the pressure is further reduced through the expansion valve 12, where it evaporates, absorbs heat, and flows into the circulation chamber 4. The air taken in through the ventilation chamber 5 is cooled to below the dew point and dehumidified.

Therefore, if heated drying air is passed through the drying chamber 3 from above the circulation chamber 4 in the direction of the solid line arrow and is applied to the grains for drying, the drying air absorbs the moisture evaporated from the grains themselves and absorbs moisture. Ventilation room 5 as dry wind
After being exhausted into the air, it is sucked into the circulation chamber 4, hits the evaporator 13, dehydrates it without freezing, becomes dry air, and is heated again in the condenser 10 to form the drying chamber 3.
Repeat the cyclical action that is sent to the This repeated circulation of drying air gradually dehumidifies and dries the grain. The moisture content detector 18 detects when the grain layer facing the ventilation side, that is, the upper part of the drying chamber 3 in this embodiment, approaches the final finished moisture content, for example, about 14%.
When detected, the operation of the compressor 9 is stopped via the controller 19, and the operation of the heat pump 8 is also stopped.
Then, the drying air that was being circulated through the drying chamber 3 and the circulation chamber 4 by the blower 7 becomes drying air that is not affected by the dehumidification effect of the heat pump, passes through the grain layer, and is discharged into the ventilation chamber 5. Since the air is not dehumidified, it becomes humid air that has absorbed moisture. Therefore, when this humid room-temperature drying air is directed into the drying chamber 3 by the blower 7 in the same direction as described above and is applied to the grain layer in a stationary state, the upper layer is dried to a moisture content close to the final finishing moisture content. The grain layer reversely absorbs moisture contained in the circulating humid room-temperature dry air through a hygroscopic reaction phenomenon, increasing the moisture content of the grain itself and lowering the humidity of the dry air. As the low-humidity drying wind gradually passes through the grain layer from the upper layer to the lower layer, the moisture in the lower grain layer is absorbed by the drying wind, and drying progresses. The moisture-absorbing, completely humid room-temperature drying air passes through the circulation chamber 4 and is again applied to the grains in the upper layer, repeating the above-mentioned process.

As a result, the difference between the dryness of the grain layer located in the upper layer and the dryness of the grain layer located in the lower layer is gradually reduced, until the difference in dryness disappears, and all of the grains have a final finished moisture content, e.g. When it reaches 14%, the operation of the blower 7 is stopped and the drying work is completed.

In short, in the present invention, the grains stacked and stored in the drying chamber 3 in a stationary state are dried by blowing circulating drying air, and the drying action of the circulating drying air allows the grains facing the ventilation side to be finished in the final finish. When the moisture content approaches the grain, instead of the circulating drying hot air, humid room temperature air is circulated and continuously exposed to the grain to dry it to a uniform finished moisture content. Even if the drying work is carried out by stacking the grains in the drying chamber 3 under the drying condition, there will be a difference in the dryness between the dryness of the grain facing the drying air blowing side and the dryness of the grain layer facing the ventilation side. This has the effect that all the grains can be uniformly dried to the desired finished moisture content.

[Brief explanation of the drawing]

The drawing shows an embodiment of an apparatus using the method of the present invention, and shows a longitudinal sectional front view. 1...Drying room, 3...Drying room.

Claims (1)

[Claims] 1. Dry the grains stacked in a drying chamber under a static state by blowing circulating drying air on them, and when the grains facing the ventilation side approach the final finished moisture content due to the drying effect of the circulating drying air. A method for uniformly drying grains, which is characterized in that the grains are dried to a uniform finished moisture content by continuously blowing humid room-temperature air on the grains while circulating instead of circulating drying air.