JPH0668437B2 - Control method of grain dryer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grain dryer equipped with a combustion device for generating hot air for ventilation drying of grains with hot air. The present invention relates to a control method for holding in.

2. Description of the Related Art Conventionally, grain dryers that dry and dry grains with hot air are widely known and put to practical use, as described in, for example, Japanese Patent Publication No. 48-36753. In addition, as a method for drying paddy rice seed, a method for drying efficiently at a relatively low temperature when the water content is high and increasing the drying temperature as the water content decreases so that the germination rate does not decrease and the drying efficiency is high is It is already known as described in Japanese Patent No. 59-1442.

Then, in this type of grain dryer or drying method, feedback control is performed to detect the temperature of hot air during operation and increase or decrease the combustion amount of the combustion device so that the temperature is maintained at a preset value. Is going.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in the grain dryer, the conventional feedback control for increasing / decreasing the combustion amount of the combustion device is used in the case of seed drying or the like in which the suitable temperature for drying the grain is relatively low. Moreover, when the outside air temperature is relatively high,
In some cases, the combustion amount must be reduced below the minimum combustion state of the combustion device. In such a case, if the combustion amount is reduced, the combustion state becomes extremely unstable.

Therefore, in view of the above-mentioned conventional problems, the present invention presets an appropriate temperature for drying grains, detects hot air temperature during drying, and performs control to increase / decrease the combustion amount of the combustion device, which is preset. By determining the outside air temperature that can maintain the appropriate temperature by controlling the combustion amount from the heating temperature to the minimum combustion amount based on the appropriate temperature and the minimum combustion amount of the combustion device, the detected outside air temperature exceeds the outside temperature that can maintain the above appropriate temperature. In the range where the combustion amount is reduced, the combustion of the combustion device is controlled to be intermittent, especially when drying at a relatively low temperature, such as seed drying, and when the outside air temperature is relatively high, or the outside air temperature is high. It is an object of the present invention to establish a control method for a grain dryer that can maintain an appropriate drying temperature even in a state of large fluctuations in height.

Means for Solving Problems The present invention has developed the following method as a technical means for achieving the above object.

That is, the control method of the grain dryer according to the present invention, in the grain dryer provided with a combustion device for generating hot air for ventilation drying of the grain, preset an appropriate temperature for drying the grain, during drying. The hot air temperature is detected to control the increase / decrease of the combustion amount of the combustion device, and the proper temperature is set by the increase / decrease control of the combustion amount from the heating temperature to the preset optimum temperature and the minimum combustion amount of the combustion device. Determine the outside air temperature that can be maintained, and control the hot air temperature to a preset appropriate temperature by controlling the combustion of the combustion device in the range where the detected outside air temperature exceeds the outside temperature that can maintain the above appropriate temperature and the amount of combustion decreases. It is to hold it.

In a grain dryer, the appropriate temperature of hot air during drying depends on the type of grain to be dried.For example, in the case of seed drying, a relatively low temperature is used in order not to impair the germination of seeds. Appropriate. Therefore, when drying the grain, an appropriate temperature is set in advance. During the drying of the grain, the hot air temperature is detected, and the combustion amount of the combustion device is controlled to increase or decrease so as to be maintained at the preset proper temperature. Then, during this control, the outside air temperature that can maintain the appropriate temperature is calculated by the combustion amount increase / decrease control from the heating temperature by the minimum combustion amount of the combustion device to the minimum combustion amount, and the detected outside air temperature is the above. In the range in which the combustion amount is reduced by exceeding the outside air temperature at which the proper temperature can be maintained, control is performed to intermittently combust the combustion device.

Therefore, especially when the drying temperature is relatively low, such as seed drying, and the outside air temperature is relatively high, or even when the outside air temperature fluctuates greatly between high and low, the combustion amount is controlled by simply increasing or decreasing the combustion amount. Proper control is performed without the combustion state of the device becoming unstable.

Example One example of the present invention will be described below.

Generally, the drying capacity of a grain dryer is determined by the quality and amount of drying air delivered to the grain. That is, there is a relationship of drying capacity = air volume × temperature.

On the other hand, the drying air is hot air heated by the combustion device, but the combustion amount in the combustion device has an appropriate range in relation to the air amount, and the minimum combustion amount is specified in particular, and combustion is performed below the minimum combustion amount. If control is performed to reduce the amount, the combustion state becomes extremely unstable.

By the way, the seeds are dried at a relatively low temperature so as not to impair the germination force, but when the outside air temperature is high, even if the combustion amount of the combustion device is set to the minimum combustion amount, the hot air temperature is Sometimes it is too expensive. For example, under the condition that the preset proper temperature is 40 ° C and the minimum heating (rise) temperature by the combustion device is 12 ° C, if the outside air temperature absorbed is 28 ° C or less, combustion in the combustion device An appropriate temperature can be maintained by increasing / decreasing the amount. However, when the outside air temperature exceeds 28 ° C., the hot air temperature becomes too high even if the combustion amount of the combustion device is the minimum amount, and the proper temperature cannot be maintained.

Therefore, the method according to the present invention performs control to detect the hot air temperature during drying and increase or decrease the combustion amount of the combustion device. Determine the outside air temperature that can maintain the proper temperature by controlling the combustion amount increase / decrease from the warm temperature to the minimum combustion amount, and in the range where the combustion amount is reduced when the detected outside air temperature exceeds the outside air temperature that can maintain the above appropriate temperature, the combustion of the combustion device is performed. The intermittent control is performed to maintain the hot air temperature at the preset proper temperature. If the hot air temperature is maintained at the set value during the intermittent combustion control, the control is shifted to the combustion amount increase / decrease control. For intermittent control of combustion in the combustion device, a control means for automatically repeating digestion and ignition is adopted.

The method according to the present invention is particularly suitable for safely performing seed drying, but can also efficiently dry general grains without causing overdrying or underdrying. In the case of a small amount of drying, safe drying control can be performed without falling into an overdrying state.

The drawing illustrates an apparatus for carrying out the method of the invention. 1 is a temperature setting unit for setting an appropriate temperature for drying, 2
Is an outside air temperature detection unit, 3 is a hot air temperature detection unit, 4 is a grain moisture detection unit, 5 is a comparison calculation unit, 6 is a combustion amount increase / decrease control unit, 7 is a combustion interruption control unit, and 7 Inside, the combustion amount increase / decrease control unit operates so that the hot air temperature detected by the hot air temperature detection unit 4 reaches the set temperature, and the combustion amount of the combustion device is increased / decreased. When the combustion amount increase / decrease control unit 6 detects that the preset proper temperature is not reached even if the combustion device has a minimum combustion amount by this control, the combustion interrupt control unit 7 operates to cause the combustion of the combustion device. Is controlled intermittently,
The hot air temperature is maintained at the set value. As mentioned above,
The transition from the increase / decrease control of the combustion amount to the intermittent combustion control is performed when the outside air temperature detected by the outside air temperature detection unit 2 exceeds a certain value. That is, heating (increased) by the preset proper temperature and the minimum combustion amount of the combustion device.
Depending on the relationship with the temperature, the outside air temperature that can maintain an appropriate temperature by the combustion amount increase / decrease control up to the minimum combustion amount is required.
This makes it possible to control by the outside air temperature.

EFFECTS OF THE INVENTION According to the present invention, an appropriate temperature for drying grains is set in advance, the hot air temperature during drying is detected, and control is performed to increase or decrease the combustion amount of the combustion device. The range in which the amount of combustion is reduced when the detected outside air temperature exceeds the outside air temperature that can maintain the above appropriate temperature by obtaining the outside air temperature that can maintain the appropriate temperature by controlling the combustion amount increase / decrease from the heating temperature to the minimum combustion amount Then, by controlling the combustion of the combustion device intermittently, especially when drying at a relatively low temperature, such as seed drying, when the outside air temperature is relatively high, or the outside air temperature fluctuates greatly between high and low. Even in the state, the effect that the proper drying temperature can be maintained can be obtained.

[Brief description of drawings]

The drawings are block diagrams showing an example of an apparatus for carrying out the method for controlling a grain dryer according to the present invention. 1 ... Temperature setting unit, 2 ... Outside air temperature detection unit, 3 ... Hot air temperature detection unit, 4 ... Grain moisture detection unit, 5 ... Comparison calculation unit, 6 ... Combustion amount increase / decrease control unit, 7 ... ... Combustion intermittent control unit

Claims (1)

[Claims] 1. A grain dryer having a combustion device for generating hot air for ventilation drying of grains, wherein a proper temperature for drying grains is preset, and the hot air temperature during drying is detected to burn the device. The control is performed to increase or decrease the combustion amount, and the outside temperature that can maintain the appropriate temperature is obtained by the combustion amount increase / decrease control from the heating temperature to the minimum combustion amount based on the preset optimum temperature and the minimum combustion amount of the combustion device. Grain drying characterized by maintaining hot air temperature at a preset proper temperature by controlling the combustion of the combustor intermittently in a range where the amount of combustion decreases by exceeding the outside air temperature at which the proper temperature can be maintained. Control method.