JPS606475B2 - Hot air supply device to dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot air supply device that supplies hot air from a solid combustion furnace using solid fuel such as rice husk to one or more grain dryers.

In general, in grain dryers, it is necessary to accurately control the hot air temperature during drying over a wide range to prevent grain cracking and quality deterioration, and for this reason, easy-to-control liquid fuel such as kerosene is used in the hot air generating section. A burner is installed. However, in recent years, it has become difficult to obtain such liquid fuels cheaply and in large quantities, and as an alternative fuel, agricultural wastes such as rice husks, which are easily available to farmers, are used as a heat source by burning them in solid combustion furnaces. It is being proposed to use hot air for drying.qAnd conventionally, it is very difficult to control the hot air temperature depending on the amount of combustion in a solid combustion furnace, so hot air is used just before the dryer. There is a method that adjusts the temperature of the hot air by mixing outside air.

However, when multiple dryers are installed side by side, if the amount of hot air supplied to one dryer is restricted due to the introduction of outside air, this will inevitably affect the other dryers as well. This makes control extremely complicated. In addition, using hot water as a heat medium using a spoiler or the like is not preferable because it complicates the structure and reduces efficiency. The present invention has been made in view of the above circumstances.The temperature and air volume of the hot air from the solid combustion furnace are always kept constant, and when controlling the temperature of multiple dryers in this state, it is possible to control the temperature of each dryer mutually. To provide a hot air supply device for a dryer which enables control such as intermittent operation so as not to influence each other and to prevent shell cracking during fraction drying.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In the figure, reference numeral 1 denotes a solid combustion furnace, which burns solid fuel such as agricultural waste rice husks, wood chips, charcoal, and coal to obtain combustion gas. The flow rate of the gas is controlled by the hot air control damper 3 of the duct 2 and the gas is guided to the main duct 4. Outside air is also introduced into the main duct 4 by a fresh air control damper 5, and hot air is generated by mixing these combustion gases and outside air. It is supplied to the dryer 8. The illustrated embodiment shows the case of four dryers, and accordingly, the main duct 4 is connected to each subduct 7a,
The dryers 8a, 8b, and 8c are transported through the dryers 7b and 7c. The dryer 8 is, for example, of a suction type having a blower fan 9 on the exhaust side, and the hot air forced by the hot air fan 6 is passed through the grain layer by the suction force of the blower 9 to dry the grains. Perform drying.

In this case, even when the exhaust fan 9 is started, the "subduct 7
Positive pressure is maintained inside. The capacities of the exhaust fan 9 and hot air fan 6 are set in advance. On the other hand, a discharge port 11 for discharging hot air to the outside is installed in the subduct 7 immediately before the dryer 8, and when a damper 12 is installed at the discharge row 1, when one of the discharge port 11 and the subduct 7 is opened, the other The discharge port 11 is equipped with a resistor 13 consisting of a restriction or the like equivalent to the flow resistance when the hot air passes from the subduct 7 toward the dryer 8 during drying, and is connected to the outlet 11 to prevent the supply of hot air from the subduct 7 to the dryer 8. It is designed to release the same amount of hot air to the outside. Note that the other dryers 8a to 8c are configured in exactly the same manner as described above. Since the present invention is configured in this way, when one or more dryers 8, 8a, etc. are operated in one solid combustion furnace 1, the combustion gas from the solid combustion furnace 1 is Fresh air from the outside is controlled by the dampers 3 and 5 to become hot air at a constant temperature, and this hot air is always fed in a constant amount by the hot air fan 6 from the main duct 4 to the subducts 7, 7a to 7c, and then to the dryer 8.
, 8a to 8c, and further passes through the grain layer 10 in the dryer to dry the grain.

At this time, for example, the damper 1 is placed on the side of the dryer 8.
2 is switched to close the subduct 7 and open the discharge row 1, the hot air in the subduct 7 is discharged to the outside from the discharge port 11, and the hot air introduction to the dryer 8 is stopped. By the way, in this case, the amount of hot air discharged from the discharge row 1 is controlled by the resistor 13 to be equal to the flow rate when it passes through the dryer grain bed 10, so a constant amount of hot air is always released regardless of whether the discharge port 11 is opened or closed. It begins to flow through subduct 7. Therefore, the opening and closing of the discharge row 1 on the dryer 8 side does not affect the dryers 8a to 8c or vice versa, and each dryer 8
9 8a to 8c are commonly connected to hot air, and can be individually controlled by the damper 12. Dampa there! The amount of hot air supplied to the dryer 8 can be controlled by changing the switching frequency of step 2, that is, the open time ratio of the subduct 7. This allows the optimal drying operation to be performed based on the elapse of the drying time. You get it.

In addition, in total drying in which the amount of grain incorporated is small, the number of times the grain is circulated is increased, and if it is operated under the same conditions as liquid drying, there is a risk of overdrying and cracking of the shell. Therefore, in the case of such fractional drying, intermittent operation is performed in which the damper 12 is temporarily held in a closed state (subduct closed, discharge port open) and circulation of grain is temporarily stopped. Note that such full or fractional drying operation has no effect on dryers other than the dryer as described above, so for example, in the four dryers 8, 8a to 8c in the figure, no The drying operating state may be used.As explained above, according to the present invention, the temperature and amount of hot air generated by the solid combustion furnace can be kept constant regardless of the number of dryers in operation, the drying state, etc., making it easy to control. Yes, multiple dryers 8, 8a to 8
Since the amount of hot air supplied in c can be controlled independently without affecting other amounts of hot air, the control system becomes very simple and reliable.

Generally, even when drying at the same drop rate, the moisture content of the grains differs, which necessitates separate temperature control, so the value of this effect is extremely high, and even when drying fractions, appropriate control can be achieved through intermittent operation. .

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of the apparatus according to the present invention. 1... Solid combustion furnace, 4... Main duct, 7, 7a to 7c... Subduct, 8, 8a to 8c... Dryer, 10...・Grain layer, 1
1...Discharge port, 12...Damper, 13...
...Resistor.

Claims (1)

[Claims] 1. To supply hot air from a solid combustion furnace to one or more dryers, open a discharge port in a thin duct to supply hot air to each dryer, and when one of the duct and the discharge port is opened with a damper, the other A device for supplying hot air to a dryer, characterized in that the discharge port is provided with a resistor equivalent to the hot air flow resistance to the dryer.