JPS63253246A - Method for measuring grain moisture content - Google Patents

Abstract

PURPOSE:To improve the reliability of the measurement of a grain moisture content measuring instrument, by selecting the value of a voltage which varies with the electric resistance of grains being crushed when the voltage changes from a decrease state to an increase state, and averaging values and calculating the water content of grains. CONSTITUTION:Some of grains scooped up in a bucket of a conveyor 12 are sent in the measurement part 10 of the grain water content measuring instrument. Then a driving motor is put in operation to rotate an electrode roll 16 united with a gear 40 around a shaft part 20, and grains enters a detection part 18 and crushed as the electrode roll 6 rotates. Further, a voltage is applied from a power source 38 to the contact terminal 28 of the electrode roll 16 as the grains are crushed and the potential of the electrode roll 6 is inputted to a microcomputer 34. The microcomputer 34 samples the input voltage at each constant period and selects the value at the point of time when the sampled value change from a decrease state to an increase state, and selected voltage values are averaged to calculate the grain water content, which is displayed on a display device 36.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for measuring moisture content, and particularly to applying a voltage to crushed grain and measuring the voltage that changes depending on the electrical resistance of the crushed grain. This invention relates to a grain moisture content measurement method that calculates moisture content using the following methods.

[Prior Art] Conventionally, in the drying process of grain, a grain moisture content measuring device has been used to measure the moisture content of the grain in order to ascertain the degree of drying.

This grain moisture content measuring device is provided with a pair of rotating electrode rolls. Grain is fed between these electrode rolls and crushed. Thereafter, a constant voltage is applied to a pair of electrode rolls, and as shown in FIG.
The grain moisture content is calculated from the average value (ΣV/n) of the measured values.

[Problems to be Solved by the Invention] Items are densely packed, and voltage measurements at coarse areas (high voltage areas) lack reliability. Therefore, an error occurs in the moisture content of the grain, and the actual finished drying state of the grain may not be the desired finish.

The present invention takes the above-mentioned facts into consideration and aims to provide a grain moisture content measuring method that can improve the measurement reliability of a grain moisture content measuring device.

[Means for Solving the Problems] The method for measuring grain moisture content according to the present invention involves applying a voltage to crushed grains and measuring the voltage that changes depending on the electrical resistance of the crushed grains at regular intervals. In the grain moisture content measurement method that calculates grain moisture content based on this measured value,
The method is characterized in that the measured values measured at regular intervals change from a decreasing state to an increasing state, and the selected measured values are averaged to calculate the grain moisture content.

[Operation] When the grain begins to be crushed, a constant voltage is applied to the crushed grain, and the voltage that changes depending on the electrical resistance of the grain is measured and temporarily stored. Generally, when grain begins to be crushed, its electrical resistance is low and the measured voltage is high. Therefore, for example, in the case of voltage characteristics as shown in FIG. 3, the measured voltage gradually decreases as crushing continues (range of arrow B in FIG. 3).

Therefore, this difference (a value obtained by subtracting the temporarily stored measured voltage from the next measured voltage after one cycle) is a negative value.

When the voltage is measured at regular intervals, there comes a point (peak value) where the decrease in the measured voltage reverses and increases as shown in the graph of FIG. At this peak value, the grain is dense and completely crushed, and after this point, the grain is coarse and the voltage value increases (range of arrow C in FIG. 3).

This peak value can be determined by subtracting this peak value from the next measured voltage and switching from negative to positive.

In the present invention, the measured voltage value Vm corresponding to this peak value M
(2 locations in Figure 3) are selected as targets for calculating the grain moisture content, and the sum of these ΣVm is divided by the number of measurements M (average value = ΣV m / M ), which is converted to calculate the grain moisture content. It is calculated as

As a result, measurement voltage when the grain is coarse can be omitted, leading to improved measurement accuracy and reducing the error between the actual moisture content of the grain and the desired moisture content.

[Examples] Examples according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a measuring section 10 of a grain moisture content device according to this embodiment.
A cross-sectional view is shown in which the grain dryer is disposed near the grain conveying packet conveyor 12.

A pair of electrode rolls 16 are disposed in the measuring section IO of the grain moisture content measuring device. The electrode roll 16 is made of a conductive metal material and includes a substantially disc-shaped detection section 18 and a shaft section 20 that projects from the center of the detection section 18 toward the riverside in the axial direction.

As shown in FIG. 2, the peripheral wall 19 of the detection part 18 is knurled, and furthermore, a spiral groove 21 and a notch 23 cut out in an arc shape over approximately 174 mm of the circumference are formed. has been done. The electrode roll 16 is in the case 22
It is inserted into the shaft and is pivoted to rotate around the shaft portion 20.

The case 22 is an insulating member in which a pair of through holes 24 for indicating the electrode roll 16 are bored in the center, and the shaft portion 20 of the electrode roll is inserted into the through hole 24, and the shaft portion 20 of the electrode roll is inserted into the through hole 24. It is designed to be pivotally supported via two ball bearings 26.

Ball bearings 26 for supporting the electrode roll 16
A conductive contact terminal 28 is disposed so as to be sandwiched therebetween, and the contact terminal 28 contacts the shaft portion of the electrode roll, and is connected to the control unit 14 via a lead wire. ing.

The control unit 14 includes a microcomputer 34 including a CPU, ROM, RAM, etc., a display 36, and a power supply equipment 38. The microcomputer 34 calculates the moisture content of the grain based on the measured voltage obtained from the electrical resistance of the grain, and displays the moisture content on the display 36.

On the other hand, a gear 40 is attached to the tip of the shaft portion 20 of the electrode roll 16 which is pivotally supported on the case 22 by each ball bearing 26.
are connected in a state where they are interlocked with each other. Therefore, as the gear 40 rotates, the electrode rolls 16 rotate in opposition to each other.

The connecting portion between the gear 40 and the shaft portion 20 is made of an insulator. Therefore, the electrode roll 16 and the gear 40 remain non-conductive even after being combined and integrated.

A drive motor (not shown) is disposed near the gear 40. The driving force of the drive motor is transmitted to the gear 40, and together with the gear 40, the electrode rolls 16 are rotated so as to face each other. Here, when grains are supplied between the electrode rolls 16, the grains are crushed by the electrode rolls.

The operation of this embodiment will be explained below.

A portion of the grain scooped up into packets by the packet conveyor 12 is constantly fed into the measuring section 10 of the grain moisture content measuring device following the path indicated by arrow A in FIG.

The grain moisture content is measured by rotating the electrode roll 16 to the sampling position. That is, the drive motor is activated, and the electrode roll 16 integrated with the gear 40 rotates around the shaft portion 20, so that grains enter the detection portion 18 of the electrode roll 16.

The grains entering the detection part 18 are crushed as the electrode roll 16 rotates. Further, as the grain is crushed, a voltage is applied from the power supply geodesic 38 to the contact terminal 28 of the electrode roll 16.

The voltage applied to the contact terminal 28 is applied to the grains that have entered the detection section 18 of the electrode roll 16, and the potential of the electrode roll I6 is input to the microcomputer 34. The microcomputer 34 calculates the moisture content based on the input measurement voltage and displays the moisture content on the display 36.

The procedure for calculating the water content from the measured voltage will be explained below according to the flowchart shown in FIG.

First, after clearing all variables in step lOO, ■
Set to l and M to o. Next, in step 102, it is determined whether a predetermined period of time has elapsed. This predetermined time indicates a voltage measurement cycle, and in this embodiment, one cycle is 1 second. When the predetermined time in step 102 is reached, step 10
Move to 4.

Measure the voltage VI between the electrode rolls 16, step 106
Move to. In step 106 I=1, that is, the voltage V
If the measurement of I is in the initial stage, after incrementing ■ in step 108, the process moves to step 102 and waits for the next cycle.

In step 106, if I is not 1, that is, if the voltage VI is being measured for the second time or later, the process moves to step 110, where the previous measured voltage Vl-1 is read, and then, in step 112, the current measured voltage is changed from the previous measured voltage. subtract the measured voltage of and calculate the difference DI. Once the difference DI is calculated, the process moves to step 114, where it is determined whether ■ is less than or equal to 2. If ■ is less than or equal to 2, it is the initial calculated value, so the process moves to step 108, where ■ is incremented. After that, the process moves to step 102 and waits for the next cycle.

If ■ is 3 or more in step 114, step 11
8, it is determined whether DI is positive or negative. Here, DI≦O
If this is the case, the value of DI is negative or 0, and it can be seen that it is within the range of arrow B in the graph of FIG. Therefore, the measured voltage VI is not applied as data for calculating the moisture content, and the process moves to step 116. It can be seen that when DI>O, DI is a positive value and falls within the range of arrow C in the graph of FIG. In this case, the measured voltage VI can be symmetrical as data for calculating the moisture content, but it cannot be determined whether it is at any position within the range of arrow C. Therefore, if DI>0 in step 118, the process moves to step 120. And the difference from last time D
I-1 is read, and then in step 122 it is determined whether this previous difference DI-1 is positive or negative. Here, DI-1>
0, the measured voltage VI is iv of arrow C in FIG.
It is determined that it is not the minimum value of R, and it is not applied as data for moisture content calculation, and the process moves to step 116. If DI-1≦O, it can be determined that the difference is changed from a decreasing trend to an increasing trend, that is, the measured voltage VI is the minimum peak value, and the process moves to step 123 to calculate the moisture content. Add it to Vm as a voltage. In the next step 124, the number of additions M is incremented to correspond to the number of additions of Vm, and the process moves to step 116.

In step 116, it is determined whether I=n, that is, the number of measurements is the nth time. The number of measurements n is a value corresponding to about one rotation of the electrode roll in relation to the measurement period. If the number of measurements has not reached 10 in step 116, the process moves to step 126, where I is incremented, and then the process moves to step 102, and waits for the first cycle. If the number of measurements is 10, the process moves to step 128 to find the average value Vr of the added water content calculation symmetric voltages vm. This is the number of times M of adding the symmetrical voltage Vm for water content calculation.
You can easily find it by dividing by. When the average value Vr is determined, the next step 130 is to convert the moisture content percentage based on the average value Vr, and proceed to step loo for the next measurement (measurement for one rotation of the next electrode roll 16). Move. Although the moisture content determined in step 130 is not shown in this flowchart, it is compared with the target moisture content to perform grain drying control or to display it on the display 36.

In this way, in this example, the measured electrode roll 16
The reliability of the moisture content is improved because all the voltages between the two electrodes are not applied to calculate the moisture content, and only the voltage measured when the grain is densely packed between the electrode rolls is used as the symmetric voltage Vm for calculating the moisture content. .

has the excellent effect of improving the measurement reliability of the grain moisture content measuring device.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the configuration of a grain moisture content measuring device according to an embodiment of the present invention, and FIG. 2 is a diagram similar to that of FIG. 1. A perspective view showing the fJ4i roll, FIG. 3 is a characteristic diagram 1 showing voltage measurement results applied to the present invention, FIG. 4 is a control flow chart, and FIG. 5 is a characteristic diagram showing voltage measurement results according to a conventional example. . lO... Measuring section, 14... Control section, 16... Electrode roll, 18... Detecting section.

Claims (1)

[Claims] (1) In a method for measuring grain moisture content, in which a voltage is applied to crushed grains, the voltage that changes depending on the electrical resistance of the crushed grains is measured at regular intervals, and grain moisture content is calculated based on the measured values. Grain moisture content, characterized in that the measured values measured at regular intervals change from a decreasing state to an increasing state, and the selected measured values are averaged to calculate the grain moisture content. Rate measurement method.