JPH0439028B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a grain moisture content measuring device, and in particular applies a voltage to crushed grain to measure the voltage that changes depending on the electrical resistance of the crushed grain. The present invention relates to a grain moisture content measuring device that calculates moisture content by measuring .

[Prior Art] Conventionally, in the drying process of grains, grain moisture content measuring devices have been used to measure the moisture content of grains in order to ascertain the degree of dryness.

This grain moisture content measuring device is provided with a pair of rotating electrode rolls. Grain is fed between these electrode rolls and crushed. After that, a constant voltage is applied to a pair of electrode rolls, the voltage that changes depending on the electrical resistance of the crushed grain is measured, and the moisture content of the grain is calculated from this voltage.

[Problems to be solved by the invention] However, in the conventional grain moisture content measuring device, since the voltage applied to the electrode roll is constant, the first
As shown in FIG. 0, when the moisture content of the grain is low and the electrical resistance is high, the amount of change in the moisture value relative to the amount of change in the measured voltage (V) becomes large. Furthermore, when the grain has a high moisture content and a low electrical resistance, the amount of change in the moisture value relative to the amount of change in the measured voltage (V) similarly increases. Therefore, as shown in FIG. 10, when calculating the moisture content of grains, the resolution of the measured voltage (V) becomes coarser than when it is within a predetermined range, so the error in the calculated moisture content increases. There was a problem.

The present invention has been made to solve the above problems, and when the amount of change in moisture value with respect to the amount of change in measurement voltage is large, the resolution of measurement voltage is reduced to an appropriate range to reduce the moisture content of grain. The purpose of the present invention is to provide a grain moisture content measuring device that can more accurately calculate grain moisture content.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes applying a voltage to crushed grains and measuring a measured voltage obtained by the electrical resistance of the crushed grains. The grain moisture content measuring device for calculating the moisture content is characterized in that a voltage variable device is provided to vary the voltage applied to the crushed grain.

In the voltage variable device of the present invention, if the measured voltage exceeds the upper limit of the predetermined range, the voltage applied to the crushed grain is lowered, and if the voltage falls below the lower limit of the predetermined range, the voltage applied to the crushed grain is reduced. It is preferable to increase the voltage applied to.

[Function] According to the present invention, a voltage variable device that varies the voltage applied to the crushed grain is provided, and when the amount of change in the moisture value with respect to the amount of change in the measured voltage is large, the voltage applied to the grain is changed. By changing the resolution, the moisture content of the grain can be calculated by adjusting the resolution of the measurement voltage to an appropriate range.

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

FIG. 1 shows a cross-sectional view of the grain moisture content measuring device according to the present invention when the measurement unit 10 is installed near the grain transport bucket conveyor 12 of the grain dryer, and the first
A block diagram of the control section 14 of the grain moisture content measuring device showing an embodiment is shown.

A pair of electrode rolls 16 are disposed in the measuring section 10 of the grain moisture content measuring device. Electrode roll 1
6 is made of a conductive metal material and is formed of a substantially disk-shaped detection section 18 and a shaft section 20 that protrudes from the center of the detection section 18 toward one side in the axial direction.

As shown in FIG. 2, the surrounding wall 9 of the detection unit 18
0 is knurled, and furthermore, a spiral groove 92 and an arcuate notch 94 extending over about 1/4 of the circumference are formed. The electrode roll 16 is inserted into the case 22 and pivoted,
It is designed to rotate around the shaft portion 20.

The case 22 is an insulating member in which a pair of through holes 24 for supporting the electrode roll 16 are bored in the center.
The shaft portion 20 of the electrode roll 16 is inserted into the electrode roll 4, and is pivotally supported on the shaft portion 20 via two ball bearings 26, front and rear, respectively.

Conductive contact terminals 28 are sandwiched between each ball bearing 26 that supports the electrode roll 16, and the contact terminals 28 come into contact with the shaft portion 20 of the electrode roll 16. and is connected to the control unit 14 via a lead wire.

The control unit 14 includes a range switch 30, a variable resistor 32 that is a voltage variable device, and a microcomputer 34 that includes a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), etc. It is composed of a display device 36 and a power supply device 38.

The range changer 30 is composed of a rotary switch or the like, and is configured to output a signal to the variable resistor 32 so as to change the resistance value of the variable resistor 32.

The variable resistor 32 changes its resistance value in response to a signal from the range switch 30, thereby changing the voltage supplied to the electrode roll 16.

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.

The power supply device 38 is adapted to supply a constant reference voltage to the range switch 30, the variable resistor 32, and the like.

On the other hand, gears 40 are coupled to the tip of the shaft portion 20 of the electrode roll 16 which is pivotally supported by the case 22 by each ball bearing 26 in a mutually meshed state. 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, even after the electrode roll 16 and gear 40 are combined and integrated, they remain non-conductive.

A drive motor (not shown) is disposed near the gear 40. Therefore, 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. For this reason, the electrode roll 16
When grains are fed between them, the grains are crushed by the electrode rolls.

Next, the variable resistor 32 of the control section 14 will be explained in detail based on FIG.

A constant voltage Vcc from power supply 38 is adapted to be applied to the crushed grain, represented by electrical resistance 72, through contact terminal 28 of electrode roll 16 via resistor 42 and relay contact 65A.

A series circuit of a resistor 44 and a relay contact 60A, a series circuit of a resistor 46 and a relay contact 62A, and a series circuit of a resistor 48 and a relay contact 64A are connected in parallel to the resistor 42, respectively. Further, a series circuit of the resistor 50 and the relay contact 66A, a series circuit of the resistor 52 and the relay contact 68A, a series circuit of the resistor 54 and the relay contact 70A, a series circuit of the resistor 42 and the contact terminal 28,
It is connected in parallel to the relay contact 65A between.

The magnitude of each resistance is smaller in the order of resistors 44, 46, . . . , 48, and larger in the order of resistors 50, 52, .

Next, the range switch 30 of the control section 14 will be explained in detail based on FIG. 4.

The range switch 30 is a rotary switch 74, 7
It is composed of 6th grade.

One end of the rotary switch 74 is grounded and the contact 74A is open. Also, contacts 74B, 74
C,...74D are the relays 60, 62,..., respectively.
...64 to the power supply device 38.
Therefore, as shown in the figure, for example, when contact 74B of rotary switch 74 is turned on, relay 6
0 is turned on, and the contact 60A is turned on.

Further, one end of the rotary switch 76 is grounded, and contacts 76A, 76B, 76C, . . . , 76D are connected to the power supply device 38 via relays 65, 66, 68, . Therefore, as shown, for example, a rotary switch 76
When the contact 76B is turned on, the relay 66 is turned on and the contact 66A is turned on.

The operation of the first embodiment configured as above will be explained.

A portion of the grains scooped up into the bucket of the bucket conveyor 12 is always fed into the measuring section 10 of the grain moisture content measuring device, following the path indicated by arrow A in FIG.

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

The grains that have entered the detection unit 18 are transferred to the electrode roll 16
It is crushed as it rotates. Furthermore, as the grain is crushed, the contact terminal 2 of the electrode roll 16
8 from the power supply device 38 to the resistance 42 of the variable resistor 32
A voltage is applied through.

The voltage applied to the contact terminal 28 is applied to the electrode roll 1
Grain that has entered the detection unit 18 of 6 (electrical resistance 7
2) and the potential of the electrode roll 16 is input to the microcomputer 34.

The microcomputer 34 calculates the moisture content based on the input measurement voltage VRx, and displays the water content on the display 36.
The moisture content is now displayed.

If the measured voltage VRx falls below the lower limit of the predetermined range as shown in FIG. 5, the displayed moisture content will have a large error. Therefore, if the moisture content is higher than the upper limit, the rotary switch 74 of the range selector 30 is rotated and the relay 6 is activated.
0, 62, . . . 64 to turn on any one of the relay contacts 60A, 62A, . . . 64A to reduce the resistance value of the variable resistor 32, and Increase the voltage applied to the contact terminal 28 of. In this case, rotary switch 76 contacts contact 76A, turns on relay 65, and turns on relay contact 65A.

For example, A(V) where the measured voltage VRx is below the lower limit value
, the corresponding moisture content B is calculated. Since the water content B is larger than the upper limit, the rotary switch 74 of the range changer 30 is rotated to turn on the relay 60. Therefore, the relay contact 60A of the variable resistor 32 is turned on, and the resistance value of the variable resistor 32 becomes small.

That is, the resistance value of the resistor 42 is R ₁ , and the resistance value of the resistor 44 is R 1 .
Letting the resistance value of R 2 be R ₂ , the combined resistance R ₀ of the variable resistor 32 is R ₀ =R ₁ R ₂ /R ₁ +R ₂ (1). Therefore, the combined resistance value R ₀ is smaller than the resistance value R ₁ . Also, in general, the relationship between voltage V and resistance R is V=IR...(2) (where I is current), and the voltage sent from the power supply 38 is
Vcc, and the electrical resistance of the grain is Rx, the measurement voltage is
VRx is expressed as VRx=Rx/Rx+R ₀ Vcc (3) from equations (1) and (2).

Therefore, the voltage of the measurement voltage VRx increases.

Therefore, as shown in FIG.
The graph of the relationship between VRx and moisture value changes from a solid line to a dashed-dotted line, and the measured voltage becomes C (V). Therefore, the resolution of the measurement voltage is reduced to an appropriate range, and an accurate moisture content can be determined.

In addition, when the measured voltage VRx becomes D (V) below the lower limit value, the range switch 30
Rotate the rotary switch 74 to turn on the relay 62. Therefore, relay contact 62A of variable resistor 32 is turned on, and the resistance value of variable resistor 32 is further reduced.

Therefore, similarly to the above, as shown in FIG. 5, the graph of the relationship between the measured voltage VRx and the moisture value changes from a solid line to a two-dot chain line, and the measured voltage G (V)
become. Therefore, the resolution of the measurement voltage VRx is reduced to an appropriate range, and an accurate moisture content can be determined.

Furthermore, when the measured voltage VRx exceeds the upper limit of the predetermined range as shown in FIG. 6, the error in the displayed moisture content similarly increases. Therefore, when the moisture content is smaller than the lower limit value, the rotary switch 76 of the range selector 30 is rotated to turn on any one of the relays 66, 68, . . . , and the relay contacts 66A, 68A, . …70
Turn on any one of A to increase the resistance value of the variable resistor 32. In this case, rotary switch 74 connects to contact 74A.

For example, L (V) where the measured voltage VRx is higher than the upper limit value
, the corresponding moisture content M is calculated. Since the moisture content M is smaller than the lower limit, the rotary switch 76 of the range changer 30 is rotated to turn on the relay 66. Therefore, relay contact 66A of variable resistor 32 is turned on, and the resistance value of variable resistor 32 increases.

That is, when the resistance value of the resistor 42 is R ₁ and the resistance value of the resistor 50 is R ₃ , the combined resistance value R ₀ of the variable resistor 32 is R ₀ =R ₁ +R ₃ (4). Therefore, the combined resistance value R ₀ is greater than the resistance value R ₁ . Furthermore, from equation (4) and equation (3) above, the voltage of the measurement voltage VRx becomes smaller.

Therefore, the measured voltage as shown in FIG.
The graph of the relationship between VRx and the moisture value changes from a solid line to a dashed-dotted line, and the input voltage becomes N (V).
Therefore, the resolution of the measurement voltage VRx is reduced to an appropriate range, and the calculated moisture content becomes an accurate value.

Similarly to the above, if the measured voltage VRx reaches H (V) above the upper limit, the range switch 3
0 rotary switch 76 and relay 68
Turn on. Therefore, relay contact 68A of variable resistor 32 is turned on, and the resistance value of variable resistor 32 further increases.

Therefore, similarly to the above, as shown in FIG. 5, the graph of the relationship between the voltage VRx and the moisture value changes from a solid line state to a two-dot chain line state, and becomes the measured voltage K (V). Therefore, the resolution of the measurement voltage VRx is reduced to an appropriate range, and the calculated moisture content becomes an accurate value.

Next, a second embodiment of the present invention will be described using FIGS. 7 to 9.

Since the measuring section of the grain moisture content measuring device is the same as that shown in FIG. 1, the explanation thereof will be omitted.

The control section of the grain moisture content measuring device is shown in FIG. 7, and includes a variable resistor 80 that is a voltage variable device and a motor 8 that moves an actuating section 86 of the variable resistor 80.
1 and a microcomputer 82.

The variable resistor 80 has resistors 83, 84, 85 and a terminal 85A connected in series. Also, resistor 83
A terminal 83A is connected to the connection point between the resistor 84 and the resistor 84.
A terminal 84A is connected to the connection point between the resistor 4 and the resistor 85. Furthermore, the rotation of the motor 81 operates an actuating section 86 to change the resistance value of the variable resistor 80.

Microcomputer 82 rotates motor 81 based on the measured voltage. Further, the moisture content is displayed on the display 89 based on the measured voltage.

The operation of the second embodiment configured as above will be explained.

FIG. 8 shows a control routine of the microcomputer 82.

When the grain that has entered the detection section 18 of the grain moisture content measuring device is crushed as the electrode roll 16 rotates, a measurement voltage VRx is read in step 100. Step 102 and Step 10
4, it is determined in step 102 whether or not the measured voltage VRx is less than or equal to the lower limit of a predetermined range, based on the relationship between the measured voltage VRx and the moisture value stored in the form of a map shown in FIG. ,
It is determined in step 104 whether the measured voltage VRx is greater than or equal to the upper limit of a predetermined range.

If it is determined in step 102 that the measured voltage VRx is below the lower limit value, the motor 84 is rotated toward the terminal 83A in step 106, and the actuating portion 86 of the variable resistor 80 is connected to the terminal 83A. Therefore, the resistance value of the variable resistor 80 is reduced and the measured voltage VRx is increased. Step 1
At 08, the flag f0 is set to ₁ .

If it is determined in step 104 that the measured voltage VRx is greater than or equal to the upper limit value, then in step 110 the motor 81 is rotated toward the terminal 85A, and the operating portion 86 of the variable resistor 80 is connected to the terminal 85A. Therefore, the resistance value of the variable resistor 80 is increased, and the measured voltage VRx is decreased. Step 1
At step 12, the flag f1 is set to ₁ .

If it is determined in step 102 and step 104 that the measured voltage VRx is within the predetermined range,
In step 114, it is determined whether the flag _f0 is set to 1. If the flag f ₀ is not set to 1, it is determined in step 116 whether or not the flag f ₁ is set to 1. If the flag f1 is not set to ₁ , the water content is calculated in step 118 using map A showing the relationship between the measured voltage and the water content shown in FIG. And step 12
0, the moisture content calculated in step 118 is displayed on the display 87.

If the flag f ₀ is set to 1 in step 114, the ninth flag is set in step 122.
The moisture content is calculated using Map B shown in the figure. At step 124, flag _f0 is reset. In step 120, step 12
The moisture content calculated in step 2 is displayed on the display 87.

If the flag f1 is set to ₁ in step 116, the moisture content is calculated in step 126 using map C shown in FIG. At step 128, flag _f1 is reset. Step 1 at step 120
The moisture content calculated in step 26 is displayed on a display 87.

As explained above, if the reference voltage is supplied to the electrode roll via the variable resistor, and the measured voltage obtained from the electrical resistance of the grain exceeds the upper limit value, the resistance value of the variable resistor is reduced. The voltage of the measurement voltage is increased, and when the measurement voltage is below the lower limit value, the resistance value of the variable resistor is increased to decrease the voltage of the measurement voltage. Therefore, it is possible to more accurately calculate the moisture content of grains by setting the resolution of the measurement voltage to an appropriate range.

[Effects of the Invention] As explained above, according to the present invention, by providing a voltage variable device that varies the voltage applied to the crushed grain, the amount of change in moisture value relative to the amount of change in measured voltage is large. In this case, since the voltage applied to the grain can be changed, the resolution of the measured voltage can be set within an appropriate range, and the moisture content of the grain can be accurately calculated.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the structure of the grain moisture content measuring device according to the present invention, FIG. 2 is a perspective view showing the electrode roll of FIG. 1, and FIG. 3 is a diagram showing the variable resistor according to the first embodiment. FIG. 4 is a circuit diagram showing the range changer according to the first embodiment, FIGS. 5 and 6 are graphs showing the relationship between the measured voltage and the moisture value according to the first embodiment, and FIG. The figure is a schematic configuration diagram showing the configuration of the control section of the second embodiment, FIG. 8 is a flowchart showing the control routine according to the second embodiment, and FIG. 9 is a diagram showing the relationship between measured voltage and moisture value according to the second embodiment. Graph showing the relationship, 1st
Figure 0 is a graph showing the relationship between measurement voltage and moisture value. 10... Measuring section, 14... Control section, 16... Electrode roll, 18... Detecting section, 30... Range switch, 32... Variable resistor.

Claims (1)

[Claims] 1. In a grain moisture content measuring device that calculates moisture content by applying a voltage to crushed grain and measuring the voltage that changes depending on the electrical resistance of the crushed grain, A grain moisture content measuring device characterized by being provided with a voltage variable device that varies the voltage applied to the grain. 2. The voltage variable device lowers the voltage applied to the crushed grain when the measured voltage exceeds the upper limit of the predetermined range, and reduces the voltage applied to the crushed grain when the measured voltage exceeds the lower limit of the predetermined range. Claim 1 characterized in that the voltage applied to the grain is increased.
The grain moisture content measuring device described in Section 1.