JPS622262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to dry the grains to a desired moisture content, it is necessary to stop the dryer properly 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, the ever-changing moisture content is measured by periodically operating a known moisture content meter such as a resistance type or a high frequency type.

A resistance-type moisture content meter is a device that crushes grains and then passes an electric current through it, and measures the moisture content of the grains from the resistance.It has a mechanically simple structure and is highly accurate, but on the other hand, it requires only one measurement sample. The disadvantage was that measurement was uneven due to the small amount.

For example, in the case of paddy, if you happen to select green rice as a sample, no matter how accurately you measure its moisture content, the measured value will be abnormally higher than the average moisture content of the entire paddy in the dryer, indicating the true moisture content. It cannot be called a rate. Such measurement unevenness occurs in exactly the same way even in the high frequency method because the sample is small.

The object of the present invention is to eliminate such drawbacks and accurately measure the moisture content of grains during drying.

The present invention will be explained based on the embodiment shown in the drawings. Reference numeral 1 denotes a conditioning chamber of a dryer, and a resistance type moisture content meter A is attached to the wall 1a of the dryer.

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.

In the present invention, a motor 9 capable of forward and reverse rotation is installed in the case 8 of the moisture content meter A, and a gear 1 is attached to the output shaft 10 of the motor 9.
A rotary cylinder 13 is connected via 1 and 12.

This is a bearing for the rotating cylinder 13.

A keyway 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 fitted therein.

18 is an extruded metal that moves only in the left and right 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 so as to face 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 into the screw rod 23, and this metal 25 is connected to a key groove 27 carved into the lower surface of the machine frame 26.
Key join to.

A shutter plate that extends freely in and out of the chamber 1 and is biased 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. Reference numeral 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 threaded 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 its tip crushes the grains that have flowed into the trough-like plate 21, and a current is passed through it to measure the moisture content from the resistance. do.

After a certain period of time (for example, 10 seconds) has elapsed after the start of locking, the motor 9 reverses and the moving metal 25 moves backward.
When this comes into contact with the limit switch Sb, the motor is cut off, which causes the electrode rod 17 and the shutter plate 18 to
Store it in its original position.

Therefore, in the present invention, the moisture content meter A is connected to the calculator C. Output indicator B is connected to calculator C.

Then, it is determined whether the electrode rod 17 is locked, that is, whether the moisture content meter A is measuring or not, by the presence or absence of the data output flag. Furthermore, the output voltage of the moisture content meter A is converted into a digital measurement value Ms (unit: %).

Next, whether this measurement is the first measurement or not s = 0
Determine whether or not. s (unit: %) is a value found from Ms according to the relational expression of the moving average method described later, but in the case of the first measurement, s=
Set it to 0.

As a result of the discrimination, if s = 0 (i.e., the first measurement), Ms is taken as the moisture content s, and s≠0.
(ie, the second or later measurement), it is determined whether Ms is Ms≧s+1. This is the current measurement value
Ms is 1 to the moisture content s at the time of the previous measurement.
(%). Normally, as drying progresses over time, Ms should decrease each time a measurement is made.
In the normal case, Ms is smaller than s+1.

If Ms is smaller than s+1, then the water content s at the time of the current measurement is calculated according to the moving average relational expression s=4×Ms+Ms/5.

On the other hand, if Ms is Ms≧s+1, then s obtained in the previous measurement is directly used as the water content s at the time of the current measurement, without calculating using the above-mentioned relational expression.

Next, target moisture content M (unit: %, M for paddy)
= 14.5%) using a variable resistor, and after the setting is completed, continue to compare the magnitude of s and M+2.

As a result, if s is large, that is, at the beginning of drying and the grains are still wet, the timer that determines the operating cycle of moisture content meter A is set to 10 minutes, and if s is small, that is, at the end of drying, the grains are If the grain is dry, set this timer to 4 minutes. Then, the output display device B receives the display command signal n from the calculator C and displays the value of s.

Next, when a certain period of time (for example, 10 seconds) has passed after the electrode rod 17 is locked, the motor 9 of the moisture content meter A
is reversed. As a result, the electrode rod 17 retreats and the data outputting flag disappears.

While the data outputting flag is off, the program of calculator C checks the elapsed time as follows.

In other words, the timer that determines the operating cycle of moisture content meter A is 10
If the timer is set to 4 minutes, it is checked whether 10 minutes have elapsed, and if the timer is set to 4 minutes, it is checked whether 4 minutes have elapsed.

The latest moisture content s calculated just before is displayed until the elapsed time of 4 minutes or 10 minutes has passed. When drying is nearing completion, shorten the timer's operating cycle to 4 minutes to measure frequently to improve accuracy, and except at the end of drying, set the operating cycle to 10 minutes to reduce the amount of grain destroyed during measurement. reduce the number of times.

When the elapsed time has elapsed, a measurement command signal m is sent to the moisture content meter A, which causes the motor 9 to rotate forward, locking the electrode rod 17 again, measuring the moisture content, and outputting the measured value Ms. The data output flag is set.

Below, repeat the above operation and sequentially calculate the water content s.
Calculate.

In the above example, the current moisture content s was calculated by adding the measured value Ms x 0.2 to the previous moisture content s x 0.8, but as the reliability of the moisture content meter used increases, the proportion of the measured value Ms It is better to increase the (weight).

Generally, it is calculated as follows: s=Ms×(100−H)+Ms×H/100. Here, H is a positive number less than 100 and means a percentage.

According to the moving average method as shown in the above equation, it is possible to not only reduce the influence of measurement unevenness and smooth out the temporal changes in moisture content, but also to store only the previous moisture content s in memory. This is advantageous because it can be implemented even with a one-chip microcomputer with a small memory capacity.

In the present invention, it is determined whether the measured value Ms falls within a certain range based on the previously calculated value of the water content s that is less affected by measurement unevenness, or whether it deviates from the range.

That is, in a system in which the moisture content meter is operated periodically to obtain the measured value Ms each time, the current moisture content s is calculated from the moving average of that value Ms and the previously calculated and stored moisture content s value. , if this measurement value
If the difference in Ms is abnormally large compared to the previous moisture content, the moisture content s is not newly calculated that time, and the previous moisture content s is used as the current moisture content s.

In this way, the water content s is calculated after determining whether the measured value Ms is normal or not, and the abnormal measured value is not adopted, and instead, the previous water content s is used as the current water content s. Therefore, according to the present invention, even if a moisture content meter measures a sample such as green rice that has an abnormally higher moisture content than other average rice, the previous moisture content s, which is the standard for comparison, is Since the influence of measurement unevenness is small, it is possible to accurately determine that this is an abnormality, and the measured value is not used in calculating the moisture content s.
Instead, the previous moisture content s calculated to reduce measurement unevenness becomes the current moisture content s, so even if the measurement sample is small, measurement unevenness does not occur and the average of all grains in the dryer is accurately calculated. It is possible to measure the target moisture content, and even if an abnormal measurement value appears at any point during drying, it can be corrected correctly. Based on abnormally high moisture measurement values, including green rice, grains can be dried for an excessively long time to prevent shell cracking. This produces the effect that grains of good quality can be dried without any risk of drying.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a part of a grain dryer embodying the present invention in cross section, Fig. 2 is an enlarged sectional view of its main parts, and Fig. 3 is a functional diagram of the present invention. The thin arrows also indicate the flow of control. Figure 4 is a flowchart.

Claims (1)

[Claims] 1. The measurement part of the moisture content meter is looked into the grain circulation path of the circulation type grain dryer, and the moisture content meter is operated periodically to determine the current moisture content from the moving average value of the measured value Ms each time. In calculating the rate s,
Compare the measured value Ms this time with the moisture content s calculated last time, and if the measured value Ms deviates from a certain range based on the moisture content s, calculate the moisture content s anew for that time. A method for measuring the moisture content of grain in a dryer, characterized in that the previous moisture content s is used as the current moisture content s without any drying.