JPS622264B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to dry the grains to a desired moisture content, it is necessary to properly stop the dryer when the grains have been dried to the desired moisture content. To do this, it is necessary to constantly and accurately measure the current value of the moisture content, which changes from moment to moment.

In the present invention, this moisture content is measured using a resistance type moisture content meter.

A resistance-type moisture content meter crushes the grain and then applies an electric current to it, measuring the moisture content from the resistance. To measure the ever-changing moisture content of drying grains using this moisture content meter, continuous measurement is not possible, so the moisture content meter is operated periodically at regular intervals of 4 to 10 minutes. The moisture content at each time point is measured by averaging the measured output values.

However, although resistance-type moisture content meters have a mechanically simple structure and are highly accurate, they have the disadvantage of causing measurement irregularities because the amount of sample measured each time is small. If grains with a moisture content higher than the above are selected as samples, there is a risk that the measured value will be abnormally high.

In view of these circumstances, the present invention constantly determines whether the measured value is abnormal or not, and if it is abnormal, shortens the operating cycle of the moisture content meter and restarts the measurement without waiting for the regular measurement interval. This reduces the effects of measurement unevenness and improves measurement accuracy.

This will be explained based on the embodiment shown in the drawings. Reference numeral 1 denotes a conditioning chamber of a dryer, and a low drag type moisture content meter A is attached to the machine wall 1a.

A downstream passage 2 communicates with the bottom of the tempering chamber 1 and is formed by two parallel perforated plates 3.

Then, the grains packed in the conditioning chamber 1 gradually flow out into the downstream passage 2, and the surface of the grains is strongly dried by the hot air from the burner 4 that crosses the passage 2 on the way.

The grains are discharged from the lower end of the flow path 2, sent to the elevator 6 by a cross-feeding helix 5 at the bottom of the dryer, and returned to the upper center of the tempering chamber 1 from the upper outlet by a tensioning helix 7.

While slowly circulating the grains in this way, the moisture inside the grains is diffused to the surface in the conditioning chamber 1, and the whole grains are uniformly dried.

A motor 9 capable of forward and reverse rotation is installed in the case 8 of the water content meter A, and gears 11 and 1 are attached to the output shaft 10 of the motor 9.
The rotary cylinder 13 is connected via 2. 14 is a bearing for the rotating cylinder 13.

A key groove 15 is carved inside the rotary tube 13, and the base end of the electrode rod 17 is slidably connected to the rotary tube 13 via a key 16 that fits into the key groove 15.

18 is an extruded metal that moves only in the leftward direction, and is screwed into a screw 19 carved in the center of the electrode rod 17.
An expansion spring 20 interposed between the extruded metal 18 and the bearing 14 urges the electrode rod 17 toward its tip.

Reference numeral 21 denotes a gutter-like plate vertically fixed to the inner surface of the machine wall 1a, and its upper edge is tilted low toward the inside of the tempering chamber 1 to reduce the resistance of grains flowing down. A receiving plate 22 having an uneven surface is attached to the inner surface of the gutter-like plate 21, facing the tip of the electrode rod 17.

Reference numeral 23 is a threaded rod having bearings at both left and right ends, and connects the gear 24 to the gear 12.

A movable metal 25 is screwed onto the screw rod 23, and this metal 25 is inserted into a key groove 2 carved into the lower surface of the machine frame 26.
Key-bind to 7.

A shutter plate 28 extends freely in and out below the gutter-like plate 21, and is urged toward the inside of the tempering chamber 1 by a contraction spring 29. A locking piece 28a is erected at the center of the upper surface of the shutter plate 28, and limit switches Sa and Sb are installed near both left and right ends of the screw rod 23. 28b indicates a stopper formed by bending the end of the shutter plate 28.

Moisture content meter A operates as follows.

First, the motor 9 begins to rotate in the normal direction, thereby rotating the rotary cylinder 13 and the screw rod 23, and the electrode rod 17 and the shutter plate 28 are respectively projected into the tempering chamber 1 by the extruded metal 18 and the movable metal 25. . And the moving metal 25 is the limit switch.
When it comes into contact with Sa, the motor 9 is cut off and the electrode rod 17
is locked at a position with a slight gap from the receiving plate 22 as shown by the solid line, and the grains flowing into the gutter-like plate 21 are crushed by the tip of the plate, and an electric current is applied to the grains to measure the moisture content from the resistance. , outputs the data voltage Er.

After a certain period of time (for example, 10 seconds) has elapsed after the start of locking, the motor 9 reverses, the moving metal 25 moves backwards, and when it comes into contact with the limit switch Sb, the motor is turned off, thereby storing the electrode rod 17 and the shutter plate 28 in their original positions. do.

Therefore, in the present invention, the moisture content meter A is connected to the calculator C. An output display B such as a liquid crystal is connected to the calculator C.

Calculator C then determines whether or not the electrode rod 17 is locked, that is, whether the moisture content meter A is measuring, based on the presence or absence of the data outputting flag, and if so, erases the flag, and then Data voltage of moisture content meter A in conversion section C1 of C
Convert Es to the digitally measured moisture content Ms (ratio of water weight contained in grains per unit weight; unit: %).

Next, in the determination unit C2 of the calculator C, the value of the measured moisture content Ms is added to a predetermined positive number (unit: %) in the calculated moisture content s(n-1) (unit: %), which will be described later, and which is stored in the storage unit C4. ) For example, compare it with the value added by 1.

As a result, if the measured moisture content Ms is small, the next calculating section C3 calculates the moving average of the measured moisture content Ms according to the relational expression sn=4×Ms(n-1)+Ms/5. Calculate the calculated moisture content Msn at the n-th measurement.

Here, s(n-1) is the calculated moisture content at the time of the previous measurement. If this measurement is the first measurement, this s(n-1) does not exist, so
Only the first time, the value of the measured moisture content Ms is used as the calculated moisture content.

The calculated moisture content sn calculated in this manner is stored in the storage section C4. and the target moisture content Ml (Ml
The unit of is % (in the case of paddy, Ml=14.5%) is set, and after the setting is completed, the calculation section C3 compares and calculates the magnitude of sn and Ml+2 (unit: %).

As a result, if sn is large, that is, in the early stage of drying and the grains are still wet, a timer set signal t1 is output that sets the operating cycle of moisture content meter A to 10 minutes, and if Msn is small, that is, when the grains are dry If the grain is dry in the latter half of the period, a timer set signal t2 is issued to set the operating cycle to 4 minutes. In either case, the value of sn is displayed on display B.

A timer built in the control unit C5 measures whether the time set by the timer set signals t1 and t2 has elapsed, and the set time of 10 minutes or 4 minutes is measured.
When the minute has elapsed, a measurement command signal a is sent to the moisture content meter A.

The motor 9 of the moisture content meter A is activated by the measurement command signal a.
rotates forward and perform the measurement again as described above.

In the process of repeating such measurements, if you crush grains, such as green rice, whose moisture content is higher than the average of all grains in the dryer, the measured moisture content
Despite the progress of drying over time, Ms becomes larger than the previous measured value and becomes an abnormal value, and this is converted into the previously calculated moisture content s(n-1) in the discriminator C2. Predetermined positive number (unit: %)
For example, when compared with the value added by 1, Ms is larger.

In such a case, the moving average calculation according to the above relational expression is not performed, but instead, 1 (no unit) is added to the abnormality memory of the control unit C5, and the operating period of the moisture content meter A is set to 2 minutes. This outputs a timer set signal t3 to set the timer to 2, and thereby the timer of the control unit C5 measures whether 2 minutes have elapsed.When 2 minutes have elapsed, a measurement command signal a is output to the moisture content meter A, and the measurement command signal a is output. Restart the moisture content meter A and take the measurement again.

Then, as mentioned above, the value of this measured moisture content Ms is compared with the value obtained by adding 1 (unit: %) to the previous calculated moisture content s(n-1), and as a result, if the measured moisture content Ms is small, Since this is a normal measurement, the calculated moisture content sn is calculated according to the above-mentioned relational expression, and this is displayed on the display section B, and the abnormality memory is cleared to return to 0.

Even if the moisture content meter A measures again, if the measured moisture content Ms is larger than the calculated moisture content s(n-1)+1 and the measured value is abnormal again, 1 is added to the abnormality memory to make it 2, and 2. Repeat the measurement in minutes. If the abnormality memory exceeds a predetermined value (for example, 3 (no unit)), the abnormality memory is cleared regardless of the value of the measured moisture content Ms, and the moisture content meter A is returned to normal operation cycle. Return to

In this way, if the value of the measured moisture content Ms is continuously abnormal, re-measurement at short intervals can be aborted after a predetermined number of times (for example, 3 times) and returned to the normal cycle of 4 minutes or 10 minutes, which will prevent crushing. This is convenient because the amount of grain destruction caused by this process can be minimized.

In short, in the present invention, a value obtained by adding a predetermined positive number such as 1 to the previous calculated moisture content s(n-1) and the current measured moisture content Ms
The discriminator compares the current measurement value with the value of s and determines whether or not the current measurement value is abnormal. If it is abnormal, the calculated moisture content s is not calculated and the calculation is performed at a short cycle less than half of the normal operating cycle. Since the moisture content meter A is operated again and the measurement is repeated, errors caused by uneven measurement, which are common with resistance moisture content meters, are corrected at an early stage, and the measurement accuracy is improved.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a part of the grain dryer used in the present invention, Fig. 2 is an enlarged sectional view of its main parts, Fig. 3 is its block diagram, and Fig. 4 is its flowchart. It is. A is a resistance type moisture content meter, C is a calculator, C1 is its converter, C2 is its discrimination unit, C3 is its calculation unit,
C4 is its storage section, C5 is its control section, and B is its output display section.

Claims (1)

[Scope of Claims] 1. From the value of the measured moisture content Ms obtained by digitizing the data voltage Es output by the moisture content meter A by operating the resistance type moisture content meter A installed in the dryer at a constant cycle,
When calculating the nth calculated moisture content sn by moving average of Ms, the value of the measured moisture content Ms is compared with the value obtained by adding a predetermined positive number to the previous calculated moisture content (n-1). ,
As a result of this comparison, if the value of the measured moisture content Ms is larger than the value obtained by adding a predetermined positive number to the calculated moisture content s(n-1), the calculated moisture content sn is not calculated and the measured moisture content The value of Ms is the calculated moisture content s(n-
A method for measuring the moisture content of grains in a dryer, characterized by restarting the moisture content meter A at a cycle shorter than the measurement cycle of the moisture content when the moisture content is smaller than the value obtained by adding a predetermined positive number to 1). . 2. The method for measuring the moisture content of grain in a dryer according to claim 1, wherein the predetermined positive number added to the previously calculated moisture content s(n-1) is 1.