JPH0560983B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the amount of air blown in a grain dryer, and particularly to a method for controlling the amount of air blown in a hot air dryer that dries grain with hot air.

[Conventional technology]

Conventionally, hot air generated by a hot air generation device is passed from a hot air chamber whose walls are made of wire mesh to an air exhaust chamber whose walls are made of wire mesh, and then is retained in a drying chamber between the hot air chamber and the air exhaust chamber. A hot air dryer is known that dries grains and discharges hot air to the outside using a blower. According to this hot air dryer, a predetermined amount of grain loaded in the hot air dryer is retained in the drying chamber, hot air is passed through the drying chamber to dry the grain retained in the drying chamber, and the grain is circulated. This dries the whole grain.

Here, the temperature of the hot air of the hot air dryer is determined depending on the type of grain, the outside temperature, and the amount of grain loaded, and generally the amount of fuel supplied increases as the amount of grain loaded increases. It is controlled to increase and become high. Furthermore, the amount of air blown by the blower is set at a constant value in accordance with the maximum amount of grain to be loaded in order to prevent grain temperature from increasing more than necessary. Also,
As the grain is dried over time, the moisture content of the grain decreases, and the humidity of the air discharged from the blower decreases over time, as shown in FIG. 2.

[Problem that the invention seeks to solve]

However, in conventional hot air dryers, the amount of air discharged from the blower is controlled at a constant level, so even if the degree of drying of the grain progresses and the relative humidity of the air blown air decreases, the drying capacity is still sufficient. The air that is being blown will also be exhausted from the blower.
The problem was that there was a lot of energy loss.

The present invention was made to solve the above problems, and an object of the present invention is to provide a method for controlling the amount of air blown in a grain dryer that can realize energy saving.

[Means for Solving the Problems] In order to achieve the above object, the present invention allows hot air generated by a hot air generation device to pass through a drying chamber and is blown by an air blower to be discharged to the outside. In controlling the amount of air discharged from the air blower of the grain dryer that dries the grain retained in the drying chamber, the humidity of the air that has passed through the drying chamber is detected by a humidity sensor. , the amount of air blown is controlled so that the detected humidity of the blown air does not fall below a predetermined value.

[Effect]

In the present invention, the humidity of the air that has passed through the drying section is detected by a humidity sensor, and the amount of air that is blown is controlled so that the humidity of the air does not fall below a predetermined value. The humidity of the air that has passed through the drying section fluctuates depending on the outside air humidity and the moisture content of the grain. The amount of air blown can be appropriately controlled according to the moisture content of the air.

For example, when the outside air humidity is constant, the amount of air blown is controlled to decrease as the drying process progresses and the moisture content of the grain decreases. The amount of air blown can be controlled by controlling the opening degree of a damper provided in the air duct or by controlling the rotation speed of the electric motor of the air blower. Here, when controlling the amount of air blown by controlling the rotational speed of the electric motor, the rotational speed is reduced as the moisture content of the grain decreases, so energy consumption can be reduced. I can do it. Moreover, when reducing the amount of air blown, the amount of air of the hot air generating device is reduced accordingly, so that the energy consumption on the side of the hot air device can be reduced.

In addition, for example, if the outside air humidity decreases after the drying process progresses and the air volume is reduced as the moisture content of the grain decreases, the humidity of the hot air supplied to the grains decreases, and the humidity of the blast air decreases to a predetermined level. Since the air flow rate is further reduced so as not to fall below the value, fuel consumption can be further reduced.

Further, for example, when drying grains that have already been mostly dried, the humidity of the air blown at the beginning of drying is less than a predetermined value, and drying is performed with a low amount of air blown from the beginning of drying, so fuel consumption can be saved.

〔Effect of the invention〕

As explained above, according to the present invention, the humidity of the air that has passed through the drying section is detected by the humidity sensor, and the amount of air that is blown is controlled so that the detected humidity does not fall below a predetermined value. The effect of this is that the air that is being used is not discharged, resulting in energy savings.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a schematic cross-sectional view of a hot air dryer equipped with an air flow rate control device to which the present invention is applicable.

Inside the hot air dryer main body 10, a hot air chamber 14 configured with a ventilation wall surface 12 such as a wire mesh is arranged. Disposed on both sides of the hot air chamber 14 is an exhaust chamber 18 having a ventilation wall surface 16 facing the ventilation wall surface 12 . The chamber 11 between the ventilation wall surface 12 and the ventilation wall surface 14 functions as a drying chamber in which grains are temporarily retained and dried.

At one end of the hot air dryer main body 10, a hot air generating device 20 configured with a burner etc. is arranged so as to introduce hot air into the hot air chamber 14.
At the other end of the exhaust chamber 18, a blower 22 configured with an axial fan is arranged to exhaust the hot air that has passed through the exhaust chamber 18 to the outside. The blower 22 is an electric motor 2
2A, an impeller 22B and guide vanes 22C fixed to the output shaft of an electric motor 22A, and a damper 24 for changing the opening area of the suction port is arranged on the suction side of the blower 22. This damper 24 is configured so that its opening area can be changed by being rotated by a step motor 26. Furthermore, a humidity sensor 23 is attached to the discharge side of the blower 22 to detect the humidity of the air discharged from the blower.

The step motor 26 is connected to an output port 30 forming a control circuit. The control circuit includes an output port 30 and a central processing unit (CPU) 3.
2. It is configured to include a random access memory (RAM) 34, a read only memory (ROM) 36, an input port 38, and buses such as a data bus and a control bus that connect these. Input port 38 has an analog-to-digital converter (ADC)
Humidity sensor 23 via 40 and buffer 41
is connected. Output port 30 is further connected to fuel pump 42 . The fuel pump 42 is connected to a fuel tank 44 via piping, and is also connected to the hot air generator 20 via a fuel transport pipe. The above-mentioned ROM 36 stores in advance a control routine program to be described below.

Next, the operation of this embodiment will be explained while explaining the control routine shown in FIG.

First, in step 100, the humidity sensor 23
In step 102, the current humidity W detected and digitally converted and stored in the RAM is imported, and in step 102, the current humidity W and the preset limit humidity are input.
Compare with W ₀ (e.g. 80%). Step 102
When the current humidity W is determined to be equal to or higher than the limit humidity _W0 , for example in the early stage of drying, the damper is opened and the damper opening degree is fully opened to increase the amount of air blown. On the other hand, when the current humidity W is determined to be less than the critical humidity _W0 in step 102, for example, when the drying of the grain has progressed to a certain extent and the moisture content of the grain has decreased, the damper is controlled in the direction of closing and the amount of air blown is is controlled so that it is reduced.

Note that when drying grains that have already been mostly dried, the humidity of the air being discharged is low, so the current humidity W is determined to be less than the critical humidity W ₀ in step 102 in the early stage of drying, and a constant and low air flow is performed. Drying is performed by air volume.

As a result of the above, the humidity of the air blown is controlled to reach the limit humidity, and at this time the amount of air blown gradually decreases as shown in FIG.

Here, air-fuel ratio control and hot air temperature control are normally performed to improve the combustion efficiency of the hot air generator, and the residual oxygen concentration in the hot air is reduced to O ₂ (not shown).
The temperature of the hot air is detected by a temperature sensor (not shown), and by controlling the amount of air supply, the air-fuel ratio is controlled to be the stoichiometric air-fuel ratio, and the temperature of the hot air is controlled to be the set temperature. controlled. Therefore, the amount of hot air generated by the hot air generator changes depending on the amount of air discharged from the blower.

The hot air generated by the hot air generating device is discharged from the hot air chamber to the outside through the drying chamber and the exhaust chamber by the blower, and when the hot air passes through the drying chamber, the grains are dried.

Note that although an example has been described above in which the amount of air blown is controlled by controlling the damper opening using an axial fan, the amount of air blown may be controlled by controlling the rotation speed using a Sirotskov fan.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a hot air dryer equipped with an air flow rate control device to which the present invention is applicable, Fig. 2 is a diagram showing humidity changes in conventional air blowing, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a flowchart of the control routine of FIG. 14...Hot air chamber, 18...Air exhaust chamber, 20...Hot air generator, 22...Blower, 23...Humidity sensor.

Claims (1)

[Claims] 1. From the blowing device of a grain dryer that dries the grains retained in the drying chamber by passing the hot air generated by the hot air generating device through the drying chamber and blowing it with a blowing device and discharging it to the outside. In controlling the amount of air blown to be discharged, the humidity of the air that has passed through the drying chamber is detected by a humidity sensor, and the amount of air blown is controlled so that the humidity of the detected air does not fall below a predetermined value. A method for controlling the amount of air blown in a grain dryer, characterized by: