JPS6130192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the loading amount in a circulating grain dryer in which grain is dried by hot air while being circulated.

When drying grains such as paddy, the drying time and hot air temperature must be appropriately controlled to prevent shell cracking, etc., and an important parameter for controlling these is the amount of tension. Therefore, if the amount of filling cannot be measured accurately, the efficiency will be reduced by the error,
In some cases, the quality of the grain may be reduced.

However, in the conventional method for measuring the amount of filling, for example, a window is formed at an appropriate location in the storage tank, and a person visually checks the filling state inside the tank through the window to determine the approximate amount of filling. Since the amount of pasting was estimated and inputted through the input keys on the operation panel, it was not possible to eliminate the possibility of input errors or visual errors, and the accuracy was poor, so it was difficult to ensure proper drying. I couldn't do it.

The purpose of this invention is to eliminate the above-mentioned drawbacks, and while the top surface of the grain in the storage tank that is in contact with the outside air is at a temperature equal to the outside temperature, any part of the grain inside the tank is heated due to the self-heating phenomenon of the grain. After a certain period of time, the temperature is at least 5 to 6 degrees higher than the outside temperature.
Focusing on the fact that it has a temperature distribution, we installed a temperature sensor in the storage tank and measured the elapsed time until the sensor output reached the lowest value when the grain was circulated. It is an object of the present invention to provide a method for measuring the amount of filling in which the amount of filling in is automatically estimated without going through the steps, and the possibility of input errors, visual confirmation errors, etc. is completely eliminated.

In order to achieve the above object, this invention provides a temperature sensor in the storage tank, reads the change in the output of the sensor by igniting a burner and circulating the grain, and determines that this output is the lowest value from the start of the grain circulation cycle. The feature is that the amount of filling is determined from the elapsed time until reaching .

Figure 1 is a diagram schematically showing the main parts of a circulating grain dryer that implements the measurement method according to the present invention, and Figure 2 is a diagram showing the output of the temperature sensor when grain is circulated in the same dryer. FIG. 3 is a diagram showing time characteristics.

In FIG. 1, a temperature sensor 2 is provided at a suitable location within a storage tank 1, and this sensor 2 is adapted to measure the temperature inside the grain during the pitching stage.

Grain 3 receives hot air from a hot air blower 6 in passages 4 and 5, is conveyed to the upper part of storage tank 1 by screw conveyor 7 and circulation device 8, and is dried again by hot air in passages 4 and 5. It will be done.

By the way, if you follow the change in the output of the temperature sensor 2 when executing such a circulation cycle, you will find that the output immediately before executing the circulation cycle is generally the result of adding outside air temperature to the self-heated heat of the grain. However, as the circulation starts, as time passes, the grain that was in contact with the outside air, that is, the surface of the grain that was in contact with the outside air in the initial state, lowers and the temperature sensor As it approaches 2, its output gradually decreases. and,
The lowest level is reached when the surface reaches the temperature sensor 2, and thereafter the output rises again as the grains that have been exposed to the hot air descend. That is, in the initial stage of executing the circulation cycle, the output time characteristics of the temperature sensor 2 form a downward curve corresponding to the self-heating amount of the grain 3 itself, and the lowest point is reached at the boundary with the subsequent upward curve. will be formed. Here, although it is obvious, the relationship between the time τ from the start of the circulation cycle until reaching the lowest point and the amount of filling is shown in FIG. 3. Therefore, if this relationship can be referred to, the amount of filling can be determined from the above-mentioned time measurement results.

FIG. 4 shows a block diagram of a control section applied to the above-mentioned grain dryer, and FIG. 5 is a flowchart showing a main part of the operating procedure of the control section.

In FIG. 4, the output from temperature sensor 2 is sent to A/D converter 11 via multiplexer 10, where it is digitized and supplied to CPU 12. The CPU 12 samples the output from the temperature sensor 2 using time interrupts from the clock generator 13 at regular intervals, and sequentially writes the sample data into the RAM 14. this
Sequential writing to RAM 14 is performed until the latest data becomes larger than the previous data, that is, the second
The process continues until the lowest point of the curve shown in the figure is detected. Once the lowest point is detected, the number of interrupts up to that point is multiplied by the sampling rate, which is the clock interval, to calculate the time τ. RAM14
The amount of filling L is determined by referring to the table stored in the table.

To further explain the above operation in detail with reference to FIG. 5, first, at n10 of the main routine, a cycle start command is issued, and at n11, the clock generator
Start the motor to circulate the grain with n12, and start the burner to blow hot air with n13. On the other hand, when the clock generator 13 starts, a clock interrupt routine is executed every time interval t. This interrupt routine first samples the output of the temperature sensor 2 at n20 and writes it to the RAM 14, then increments the counter N, and then compares the size of the data written just now with the data written before. Writing data and counting up the counter N continue until the data becomes larger than the previous data. Then, when the latest data becomes larger than the previous data,
Proceeding to N23, the number of interrupts stored in the counter N is multiplied by the interrupt interval t to obtain the elapsed time τ from n10. Further, at n24, the amount of tension L is determined by referring to the relational table shown in FIG. 3, which is stored in a predetermined area of the RAM 14, and the cloth is stopped at n25.

By continuously taking in the output of the temperature sensor 2 as described above, the filling amount L can be measured. In addition, after this filling amount L is measured,
Needless to say, this value is ultimately used to control the circulation speed, hot air temperature, etc.

In this way, according to the present invention, in consideration of the temperature characteristics inside the storage tank in which the temperature at the top surface of the grain in the storage tank is the lowest and the temperature gradually rises as it goes inside, the temperature change during circulation is Since the temperature sensor is used for detection, it can be easily determined that the grain that was initially on the top surface has reached the position of the temperature sensor. In addition, since the elapsed time from the start of the circulation cycle until the temperature sensor output reaches its minimum value is correlated with the amount of filling, the amount of filling can be easily determined by knowing this elapsed time. Since there is no need to judge the amount of filling and input it, it is possible to prevent work errors. Furthermore, since the sensor does not detect mechanical displacement, it does not drift over time and can operate stably over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the main parts of a circulating grain dryer that implements the measurement method according to the present invention.
The figure shows the output time characteristics of the temperature sensor when grain is circulated in the same dryer. Further, FIG. 3 shows the relationship between the elapsed time from when the output of the temperature sensor reaches the lowest value from the start of the circulation cycle and the amount of filling. Furthermore, FIG. 4 is a block diagram of a control section applied to the above-mentioned circulating grain dryer, and FIG. 5 is a flowchart showing the main part of the operating procedure of the control section. 1...Storage tank, 2...Temperature sensor, 3...Grain, 8...
Circulation device.

Claims (1)

[Claims] 1. Install a temperature sensor in the storage tank, read the change in the output of the sensor by igniting the burner and circulating the grain, and start the loading process from the elapsed time until this output reaches the lowest value from the start of the grain circulation cycle. A method for measuring the amount of filling in a circulating grain dryer.