JPS6156459B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a resistance type moisture content meter.

A resistance-type moisture content meter measures the moisture content of grains by crushing grains such as paddy and passing an electric current through the current.

Therefore, if this moisture content meter is attached to a dryer to measure the dryness of grains over a long period of time, a large amount of grains will be crushed and wasted.

An object of the present invention is to reduce the amount of wasted grains produced during the measurement process of such a moisture content meter.

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.

In this way, while slowly circulating the grains, the moisture inside the grains is diffused to the surface in the conditioning chamber 1, and the whole grain is 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 movable electrode 17 is slidably connected to the rotary tube 13 via a key 16 that fits into the key groove 15.

Reference numeral 18 denotes an extruded metal member that moves only in the left and right direction. The extruded metal member 18 is screwed into a screw 19 formed in the center of the movable electrode 17, and an expansion spring 20 interposed between the extruded metal member 18 and the bearing 14 moves the movable electrode 17 to its tip. Force towards.

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 fixed electrode 22 having an uneven surface is attached to the inner surface of the gutter-like plate 21 facing the tip of the movable electrode 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.

Therefore, in the present invention, the locking piece 28a is erected at the center of the upper surface of the shutter plate 28, and the limit switches Sa and Sb are installed on the left and right sides of the locking piece 28a, respectively, and the limit switches Sc and Sd are also installed near both the left and right ends of the threaded rod 23. . 28b is the shutter plate 2
A stopper formed by bending the terminal end of 8 is shown.

And these switches Sa, Sb, Sc and Sd
The control unit 3 of the moisture content meter A is controlled by a timer (not shown).
0, and the control unit 30 controls the detection unit 3 consisting of a motor 9, a moving electrode 17, and a fixed electrode 22.
Control 1.

That is, when the moving electrode 17 and the shutter plate 28 are in the position indicated by the dashed dotted line in FIG.

As a result, the motor 9 is started and the movable electrode 17 is forwardly rotated by the rotary cylinder 13, and the shutter plate 28 is also advanced as the movable metal 25 moves to the left due to the rotation of the screw rod 23.

When the moving metal 25 reaches the position indicated by the broken line, the shutter plate 28 is stopped by its stopper 28b and protrudes below the gutter plate 21. Even after the shutter plate 28 has stopped, when the moving metal 25 moves to the left, it separates from the switch Sa and switches the switch 8a.
is turned off.

As a result, the motor 9 is turned off, and the movable electrode 17 stops at the position indicated by the broken line, and the grain is gently pressed between its tip and the fixed electrode 22. Then, a current is passed through the grain, and the moisture content is measured from the resistance.
The comparator 32A compares Ms with the initial reference value Mv. Note that the comparison section 32A is composed of a known circuit such as a differential amplifier.

As a result, if the measured value Ms is larger than the initial reference value Mv, HHH, meaning high moisture content, is displayed on the display section 33, and a reset signal t is sent to the timer of the control section 30.

As a result, the motor 9 begins to reverse rotation and the moving electrode 17
is retreating. The moving metal 25 also moves to the right,
The shutter plate 28 is moved backward against the contraction spring 29 via the locking piece 28a.

When the locking piece 28a comes into contact with the switch Sd, the switch Sd is turned on, the motor 9 stops, and the movable electrode 17 and the shutter plate 28 both return to the original position indicated by the dashed line.

When a predetermined period of time, for example 10 minutes, has elapsed, the motor 9 rotates in the normal direction again, and the movable electrode 17 advances to the position indicated by the broken line in the manner described above, and the fixed electrode 22
Moisture content is measured by passing an electric current through the grains that are loosely pressed between them.

If the measured value Ms at this time is smaller than the initial reference value Mv, the measuring signal m is transmitted from the comparing section 32A to the detecting section 31.
The motor 9 further rotates in the normal direction.

As a result, the moving electrode 17 and the moving metal 25 move forward to the position indicated by the solid line, and when the switch Sc is turned on by the moving metal 25, the motor 9 stops, crushing the grain between the moving electrode 17 and the fixed electrode 22, and reducing the water content. Measure.

This measured value Ms is compared with the final reference value Ml by the comparator 32B. The final standard value Ml is the target moisture content of grain, which is around 14% for paddy.

Then, from the value obtained by adding 2 to this Ml, the measured value Ms
If it is large, the comparator 32B sends a reset signal t to the controller 30, sets the timer to operate at 10 minute intervals, and reverses the motor 9 to reset the moving electrode 1.
7 and the shutter plate 18 are returned to the position indicated by the dashed line.

After 10 minutes have elapsed, the movable electrode 7 moves forward again to the position indicated by the solid line as described above, crushes the grain, and measures the water content.

If the measured value Ms is smaller than Ml plus 2, a reset signal is output from the comparator 32B to operate the timer every 4 minutes. These measured values Ms are displayed on the display section 33 every time the measurement is performed.

Then, when the measured value Ms becomes equal to the final reference value Ml, the operation of the dryer is automatically stopped.

As described above, in the present invention, at the beginning of the drying operation when the grain has high moisture content, the movable electrode 17 is advanced by a short distance and the grain is gently pressed against the receiving plate 22 to roughly measure the moisture content. When drying progresses and this measured value falls below a predetermined initial reference value, the movable electrode 17 moves forward over a long distance, crushes the grain under pressure between it and the fixed electrode 22, and precisely measures the moisture content. .

This results in the effect that only a very small amount of grain is wasted by being crushed during the measurement process of the moisture content meter.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a part of a grain dryer embodying the present invention, Fig. 2 is an enlarged sectional view of its main parts, Fig. 3 is a block diagram of the present invention, and Fig. 4 is its It is a flowchart. A is a resistance type moisture content meter, 9 is a motor, 17 is a moving electrode, 22 is a fixed electrode, 23 is a screw rod, 25 is a moving metal, 28 is a shutter plate, 30 is a control unit, 3
1 is the detection part, 32A is the comparison part with Mv, 32B is the
Comparison section with Ml, 33 is display section, Sa is limit switch.

Claims (1)

[Claims] 1. In a resistance-type moisture content meter that pinches grain between a moving electrode and a fixed electrode and measures the moisture content of the grain from the electrical resistance between the electrodes at that time, the moving electrode is moved forward, An electrode moving means that moves backward and stops, and an electrode position detection means that detects the position of the moving electrode are provided, and when the moving electrode advances to a provisional measurement position before the most advanced position where the grain is pinched, the electrode position is determined. Comparing means is provided for operating the electrode moving means to stop the moving electrode midway based on the position detection signal of the detecting means and comparing the electric resistance between the electrodes with a reference value, and based on the determination signal of the comparing means, the above-mentioned If the electric resistance value between the movable electrode and the fixed electrode that has stopped midway is greater than the reference value, the movable electrode is moved backward, and when it is smaller than the reference value, the movable electrode is advanced to the most advanced position. Moisture content measurement device for grain dryers.