JPS622263B2 - - 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, this moisture content is measured using 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 drawback is that measurement is uneven because the amount is small.

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 accidental fluctuations in measured values also occur in high-frequency moisture content meters because the sample size is small. Therefore, in order to eliminate accidental fluctuations, that is, measurement irregularities, measure 5 to 7 times in a row and use the average value as the measurement value at that point.After that, take a rest for 1 hour, then measure again continuously and take the average value. A measurement method that repeats this process has been proposed. (Unexamined Japanese Patent Publication 1973
- No. 102158). This method eliminates measurement unevenness, but since there is a period of rest without measurement, if the moisture content reaches the desired value due to drying progressing during that time, this cannot be detected, resulting in overdrying. I can't escape it.

The present invention aims to eliminate such drawbacks and to accurately measure the current moisture content at all times.

The present invention will be described based on an 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. 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 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 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.
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 forward, 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 moving metal 25.
When the moving metal 25 comes into contact with the limit switch Sa, the motor 9 is turned 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 flows into the gutter-like plate 21. The grains are crushed, an electric current is passed through them, and the moisture content is measured from the resistance.

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. A counting type output display B, such as a liquid crystal display, is connected to the calculator C.

And check whether the electrode rod 17 is locked or not.
In other words, it is determined whether the moisture content meter A is measuring or not by the presence or absence of the data outputting flag, and if the flag is present, the flag is erased, and the output voltage of the moisture content meter A is converted into a digital measurement value Ms (unit: %). Convert.

Next, determine whether this measurement is the first measurement, that is, whether n = 1. If n = 1, set Ms as it is to the moisture content s ₁ (unit %), and if n≠1, sn = Ms (n -1) Calculate the n-th water content sn (unit: %) according to the relational expression (K-1)+Msn/K.

Here, K is 3, 4, or 5, and n is an integer greater than 1.

Then, the target moisture content M (14.5% for paddy) is set using a variable resistor, and after the setting is completed, the magnitude of sn or _s1 and M+2 is compared.

As a result, if sn (or s ₁ ) is large, that is, when the grain is still wet at the beginning of drying, the timer that determines the operating cycle of moisture content meter A is set to 10 minutes, and sn (or s _{1 )} is large. ) is small, that is, when the grain is dry at the end of drying,
This timer is set to 4 minutes, and the output display B receives the display command signal n from the calculator C and displays the value of sn (or s ₁ ).

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 output flag is off, the computer C program checks the elapsed time as follows.

In other words, if the timer that determines the operating cycle of moisture content meter A is set to 10 minutes, it will check whether 10 minutes have passed, and if the timer is set to 4 minutes, it will check whether 4 minutes have passed. Check each one.

Until the elapsed time of 4 or 10 minutes has passed.
Display sn.

When the elapsed time has elapsed, a measurement command signal m is transmitted to the moisture content meter A, which causes the motor 9 to rotate forward to measure the moisture content, output the measured value Ms, and set the data output flag.

Below, the above-described operation is repeated to calculate the (n+1)th moisture content s(n+1), and s(n+1) is displayed instead of sn.

In this way, the moisture content sn is s(n-1)×1
Calculate by adding Msn x 1/K to -1/K), but if the moisture content meter used is highly reliable, reduce the value of K and calculate the moisture content.
Increase the proportion of Msn in sn.

Generally, instead of K, use any positive number H (%) less than 100, sn = Ms (n-1) x (100-H) + Msn x H/1
Calculate sn as 00.

In summary, in the present invention, the drying process is performed every 10 minutes during the initial stage of drying, or every 4 minutes during the final stage of drying.
Moisture content meter A at predetermined intervals every minute.
is operated to obtain the measured value Ms each time, and the water content sn at the nth measurement is sn = Ms (n-1) x (100-H) + Hsn x H/1
00 (H is any positive number less than 100).

In this way, the measured value Msn accounts for only a part of the moisture content sn value, so even if the sample happens to be green rice with a high moisture content and its value is abnormally large, the moisture content sn
has little effect on the value of

Therefore, the moisture content sn is less affected by variations in sample quality, etc., and the present invention has the advantage that the average moisture content of all grains in the machine can be measured accurately without any unevenness.

Moreover, the grains are usually kept in the dryer for at least 30 minutes.
It takes at least an hour and a half to complete one circuit, so 10
According to the present invention, which calculates the moisture content Msn each time from new measured values at intervals of less than a minute, it is possible to measure the next sample before the previously measured sample has completed one revolution inside the machine, and therefore the moisture content that changes over time can be measured. can be constantly tracked within a practically acceptable error range, and if the dryer's stop device is activated in this way, the dryer will be stopped immediately when the target moisture content is reached, and the dryer will be able to dry accurately with no excess or deficiency. arise. Furthermore, when averaging several measured values as in the past, a memory is required to store the measured values of several times, whereas in the present invention, only the value of the moisture content sn calculated each time is stored. This has the effect that a small capacity memory is sufficient.

[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, with thick arrows indicating information. The thin arrows also indicate the flow of control. Figure 4 is a flowchart. A is a moisture content meter, B is an output display, and C is a calculator.

Claims (1)

[Claims] 1. Operate the moisture content meter periodically to obtain the measured value Ms each time, and calculate the moisture content sn at that time from the n-th measured value Msn using the following relational expression sn = Ms ( n-1)×(100-H)+Msn×H/1
00 (H is a positive number less than 100, n is an integer greater than 1).