JPS6212857B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an automatic moisture content measurement device that is installed in a grain dryer and measures the moisture content of a sample of grain to be dried, and controls or stops the dryer. This relates to improving the operation control of a dryer after the measuring device (sequence control) fails.

[Conventional technology]

This type of automatic moisture content measuring device has a measuring part that automatically measures the moisture content of the grain being dried in a grain dryer and outputs a measured value signal, and a measuring part that automatically measures the moisture content of the grain being dried in a grain dryer and outputs a measured value signal. a target moisture content setting unit that outputs a corresponding set value signal; and a drying stop signal when the moisture content value of the grain to be dried reaches the target moisture content value by inputting and comparing the measured value signal and the set value signal; Some devices include a measurement control section that outputs , and also performs various sequence controls for automatic measurements. In this type of device, the automatic measurement operation of the automatic moisture content measuring device may become inactive. For example, hard foreign objects (such as pebbles) may get mixed into the dried grain used as a sample for measurement and damage the measuring device itself. In such a case, the grain dryer remains in an uncontrolled state because the normal automatic measurement operation (sequence control) is essentially not performed thereafter and the measurement control section does not output the drying stop signal forever.
That is, since the drying operation continues indefinitely, the grain to be dried becomes overdried, resulting in quality deterioration. Therefore, in order to prevent overdrying, it is possible to immediately stop the operation of the dryer when a failure is detected in the automatic moisture content measuring device, but if this occurs in the early stage of drying when the moisture content of the grain to be dried is high, It is predicted that the quality of the grain to be dried will deteriorate due to stuffiness and the like. Therefore, as another countermeasure, it has been considered that when a failure of the automatic moisture content measuring device is detected, only the fan of the dryer is controlled to ventilate the grain to be dried so as not to get stuffy.

[Problems to be solved by the invention]

This did not cause any problems in the early stages of drying when the moisture content of the material to be dried was still at a sufficiently high level; This causes inconveniences such as. In other words, paddy that has been continuously exposed to hot air has a temperature that rises above room temperature, and whose moisture content has decreased, and has hardened considerably. Therefore, ventilating unheated, room-temperature air through it is a method of ventilation with high humidity. become,
Paddy absorbs moisture rapidly and cracks occur.

[Means to solve the problem]

The present invention has been proposed in view of the above circumstances, and includes a measuring section that automatically measures the moisture content of grains being dried in a grain dryer and outputs a measured value signal, and a measuring section that automatically measures the moisture content of grains being dried in a grain dryer and outputs a measured value signal. A target moisture content setting unit outputs a set value signal corresponding to the target moisture content value for drying, and inputs and compares the measured value signal and the set value signal to adjust the moisture content value of the grain to be dried to the target moisture content value. In an automatic moisture content measuring device comprising a measurement control section that outputs a drying stop signal when drying is dry and performs various sequence controls for automatic measurement, an abnormal state of the sequence control of the measurement control section is detected during automatic measurement. a failure detection unit that outputs a safety stop signal when the measured value is within a predetermined high moisture content range; continues to control the operation, and when either the drying stop signal or the safety stop signal is input when the measured value is in a predetermined low moisture content range, at least the fuel to the burner of the dryer is input. A dryer stop section is provided to stop and control the supply and drying fan, and when automatic measurement becomes impossible due to some kind of hindrance during automatic measurement, that is, when an abnormal state of sequence control is detected, The present invention provides an automatic moisture content measuring device which is improved so that the subsequent operation control of the dryer is controlled separately depending on the moisture content value of the grain to be dried.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. Referring to FIGS. 1 and 2, the automatic moisture content measuring device will be explained. A rotating shaft 2 of a motor 1 is connected to an insulating gear 4 through a coupling 3 so as to rotate together with the rotating shaft 2, and is stopped under the gear 4. A rod-shaped upper electrode 6 is connected in a straight line by a tool 5.
The gear 4 is rotatably supported by a sleeve 8 attached to a housing 7, and the lower part of the upper electrode 6 is fixedly held by a nut 1 to an insulating bracket 9.
A lead wire 12 is screwed to a mounting screw 11 of the nut 10 for electrical connection. Cup ring 3
As shown in Fig. 2, the inner protrusion 13 is fitted into the groove 14 of the rotating shaft 2 to transmit power, and when a predetermined load is applied, the protrusion 13 is destroyed and the rotor rotates idly. ing. On the other hand, one end of the sample dish 16 having the lower electrode 15 is cantilevered by a shaft 18 that is electrically connected to the lead wire 17.
A gear portion 19 is communicatively connected to the aforementioned gear 4 via a gear mechanism 20. In this way, the rotating shaft 2, the coupling 3, the gear 4, and the gear mechanism 20 are normally rotated in one direction by the normal rotation of the motor 1, and the sample dish 16 moves forward and enters the dryer, and the material to be dried is placed on the lower electrode 15. Collect samples of grains, etc. Thereafter, when the motor 1 is reversed and the sample plate 16 is returned to its original position, and the lower electrode 15 is positioned in a straight line with the upper electrode 6, the upper part rotates together with the rotating shaft 2, coupling 3, and gear 4 of the motor 1 and descends. The sample on the lower electrode 15 is crushed by the electrode 6, and the moisture content of the sample is measured based on the electrical resistance between the electrodes 6 and 15. Such measurements are repeated several times. It will be done.
If there is a hard foreign object in the sample, the lowering of the upper electrode 6 is blocked and the motor 1
The coupling 3 breaks due to overload acting on the sample plate 16 and the upper electrode 6
When it stops moving, the measurement automatically stops. Next, we will explain the measurement sequence control operation and safety device for the circuit shown in Figure 3.
21 is a measurement unit that crushes the sample and measures the electrical resistance between the electrodes and generates a signal inversely proportional to this electrical resistance; 22 is an integrating circuit; 23 is a comparison circuit; 24 is a measurement interval control circuit; and 25 is a measurement number. Counting circuit, 2
6 is a measurement flag circuit, 27 is a 2-second clock pulse generation circuit, 28 is a two-stage cut-off flag circuit, which constitute a measurement control section, 29 is a failure detection section, and 30 is a moisture content storage circuit. Measuring section 21
In this case, the sample dish 16 is in the standby position, and the standby limit switch WTLS is open at that position. The sample pan 16 is moved forward by the operation of the motor 1 to collect a sample, and is stopped by opening the limit switch FWLS at the forward end, and after a certain period of time, the motor 1 is reversed and the limit switch BWLS is opened at the backward end. ing. When the power is turned on (start in Figure 6),
The INIT signal loads the counter C-1 of the measurement count circuit 25 via the NOR gate G-1 and sets the count to 11. As a result, the output Q _D becomes a high level (hereinafter referred to as H) and becomes AUTO.
A signal is generated. This AUTO signal is a signal indicating that automatic measurement is in progress, and acts as a command signal to allow the measurement count circuit 25 to count, to allow the integration circuit 22 to integrate, and to the measurement flag circuit 26 to cancel stop. The reason why the count is set to 11 is to keep the AUTO signal at H until the count is subsequently counted as 12, 13, 14, 15, and 0 and the five measurements are completed. On the other hand, the signal clears the flip-flop FF-1 of the measurement flag circuit 26, and its output Q becomes a low level (hereinafter referred to as L). Since the sample pan 16 is in the standby position, limit switch WTLS is open and FWLS and BWLS are closed. Gate Q-A
is prohibited by the L level of the AUTO signal, so the output of the gate G-2 is at the H level. Therefore, the gate G-3 is turned on, the motor forward rotation relay FWD is activated, the motor 1 is rotated in the forward direction, and the sample dish 16 is advanced and enters the dryer. When the limit switch FWLS is pushed open at the forward end, the gate G-
2's input becomes H, its output becomes L, gate G-3 is inhibited, relay FWD is inactivated, and motor 1 is stopped. On the other hand, due to the operation of limit switch FWLS,
The output of the negative input OR gate G-4 becomes H, canceling the clearing of the delay counter C-2 via the inverter I-1, and outputting it from the output Q of the free-running oscillator B-1 of the 2-second clock pulse generation circuit 27. Start counting the 2 second clock pulses. This 2-second clock pulse is a pulse signal set mainly to regulate the integration time of the integration circuit 22, which will be described later. When the count reaches 8 (16 seconds have elapsed), counter C-
The output Q _D of gate G-2 becomes H, and the inputs of gate G-5 both become H, so its output becomes L. When the output Q _D becomes L at the 16th count (32 seconds elapsed),
The output of gate G-5 becomes H, the output Q of flip-flop FF-1 of measurement flag circuit 26 becomes H, and the output becomes L. limit switch
Since BWLS is closed, the inputs of gate G-6 both become H, which turns on, activates relay BAK, rotates motor 1 in reverse, and sample plate 16 begins to move backward. The reason why the sample dish 16 is moved forward and stopped and then retreated after a certain period of time (32 seconds) is to ensure that the sample is collected on the sample dish 6 during that time. By retracting the sample pan 16, the limit switch is activated.
FWLS closes and clears delay counter C-2. The limit switch is turned on at the retreating end of the sample pan 16.
When BWLS is activated and opened, gate G-6 is prohibited, BAK is deactivated, and motor 1 is stopped.
At the same time, the delay counter C-2 starts counting the output pulses of the 2-second clock generating circuit 27 in the same way as when the limit switch FWLS is opened. When the counter C-2 counts 8 (16 seconds have elapsed), its output Q _D becomes H and its output QA becomes L. On the other hand, limit switch BWLS is open, so both inputs of 3-input NAND gate G-7 are high.
The output becomes L, and the switch circuit S-
1, close switch SW-1 and start integration. That is, when the sample is crushed and the output of the measuring section 21 becomes sufficiently stable after 16 seconds have elapsed, the integrating circuit 22 starts integrating the output. When the counter C-2 counts 9 (18 seconds have elapsed), the outputs QA and Q _D become H, and the 3-input gate G
-8 input conditions are met, and the output becomes L. This output L is the MESD signal, which indicates that one measurement has been completed. The FWD is activated, the motor 1 rotates normally again, and the sample dish 16 begins to move forward. Further, the MESD signal enters the counter C-1 of the measurement number counting circuit 25, and is incremented by one count, reaching a count of 12. At the same time, the output QA of counter C-2 becomes H,
The output of gate G-7 also becomes H, and switch SW-
1 opens and the first integration ends. When the sample pan 16 moves forward, the limit switch BWLS closes and the counter C-2 is cleared again. While the sample dish 16 is moving forward, the standby limit switch WTLS is opened and the input to the gate G-A becomes H.
Since gate G-A remains prohibited by the AUTO signal, motor 1 does not stop. That is, the counter C-1 is for counting the number of measurements, and the counter C-2 is for counting the number of measurements.
-8 to perform counting operations to output operation timing signals for the integrating circuit 22, the measurement count circuit 25, the measurement flag circuit 26, and the like. The above operation is repeated, and the number of measurements is counted by the counter C-1 of the counting circuit 25. At the end of the fifth measurement, the count returns to 0, and the output Q _D becomes L. As a result, the gate G-
When the inhibition of A is removed and the limit switch WTLS is opened, the output of gate G-A becomes L, and gate G
Gate G-3 is inhibited through -2 and relay
The FWD is deactivated and the sample pan 16 stops at the limit switch WTLS. The integrated value of the measured values obtained by each of the five measurements described above is compared with a comparison level in the comparator circuit 23. The comparison circuit 23 includes three comparison circuits F-1, F-2, F-3.
F-1 has the lowest comparison level and becomes the target value, while F-3 and F-2 have the lowest comparison level.
A voltage dividing circuit consisting of resistors R ₁ , R ₂ , and R ₃ is set above and below at a predetermined distance from each other so that the voltage is higher than -1. The integrated voltage is R ₄ , VR ₁ ,
A voltage divider in _R5 is applied to the inverting input of each comparator. Furthermore, the reference voltage for each comparison level _of the comparison circuit 23 can be determined by changing the value of the resistor VR ₂ using a rotary switch RS serving as a target water content setting section connected in series to a voltage dividing circuit of resistors R ₁ , R ₂ , and R 3 . It can be changed by That is, to select and set the user's target moisture content, the rotary switch
By changing VR ₂ using RS, the entire level of each comparison circuit can be changed up or down. The output of each comparison circuit is the measurement interval control circuit 24.
is added to the inputs B, C, and D of the counter C-3, and is loaded when the carry output CA ₁ of the counter C-1 of the measurement number counting circuit 25 becomes L, and the count according to the inputs B, C, and D is loaded. loaded into. Counter C-3 is the 8-minute clock pulse generation circuit B-
2 pulses are counted, and before reaching 15 counts and returning to count 0, the carry output CA ₂ becomes L.
For example, if the output of F-3 is 19% or less of H, it will take 64 minutes at count 8, if F-3 and F-2 go to H, it will take 32 minutes at count 12, and if all of them are H, it will take 14 minutes.
They are now loaded every 16 minutes.
Therefore, the measurement interval time is set depending on the moisture content at that time, and when that time elapses, the carry output CA ₂
The counter C-1 is loaded again and the next measurement is started. On the other hand, the flip-flop of the moisture content storage circuit 30
FF-4 is the counter C of the measurement interval control circuit 24.
When -3 was loaded at 32 minutes, it was operated under the same conditions and the output Q became H, and it is remembered that the material to be dried was dried to a state close to the target moisture content. Next, when the moisture content reaches the target value or less, all outputs (first signals) up to the comparator circuit F-1 become H.
At this time, the output of F-1 (output COFF) is:
It is applied to the input D of the first stage flip-flop FF-2 of the two-stage cutoff flag circuit 28, and the H of the carry output CA ₁ of the measurement number counting circuit 25 activates the flip-flop FF-2 through the gate G-10 and outputs Q. (second signal) becomes H, and it is stored that the drying has reached the target value. Next, the measurement is restarted 16 minutes later, and when the measurement is performed five times, if the integrated value is again below the target value, the input to the next stage flip-flop FF-3 of the two-stage cut-off flag circuit 28 is determined. D, output COFF
Since the output Q of the first-stage flip-flop FF-2 is applied, the flip-flop FF-3 is operated by the carry output _CA1 of the measurement number counting circuit 25. Then, the L of the output Q activates the fuel relay FUEL as a dryer stop section, and the fuel is stopped. Subsequently, after several minutes, the gate G-11 is turned on by the L output QT of the timer B-2, the blower relay FAN is activated, the blower is stopped, and the drying is completed. At the same time, the measurement interval control circuit 24 is cleared and the automatic measurement function, that is, the sequence control is stopped. When the target set value is first reached and then measured again, if the target value is not reached due to uneven drying, etc., that is, when a high moisture content is detected, the output signal COFF is set to L and doubles. Flip-flop on the tier
Since the input D of FF-3 is L, the stop signal does not appear and the measurement is repeated again. At this time, the output Q of flip-flop FF-2 is
2 to the B input of counter C-3, the next measurement is loaded to take place in 16 minutes, even though the output signal COFF is low. Further, the operation detection by the failure detection unit 29 can be performed by ensuring that the AUTO signal does not disappear even after a predetermined sequence control of the measurement operation is stopped and a certain time period has elapsed. That is, if there is a hard foreign object in the sample, the lowering of the upper electrode 6 will be blocked and the coupling will break before the limit switch BWLS is opened. At this time, since the limit switch FWLS is closed, both inputs of gate G-4 become H, and from then on, the output of gate G-4 becomes L.
becomes. Therefore, both free-running oscillator B-1 and delay counter C-2 are cleared and held inactive. As a result, from now on the input of gate G-8 becomes H.
The MESD signal will not be output from gate G-8. Therefore, the counter C-1 of the measurement number counting circuit 25 does not count up and is set to AUTO.
The signal remains fixed at H, the rotating shaft of the motor 1 remains reversed, and subsequent sequence control is stopped, resulting in an abnormal state. On the other hand, counter C-1
The CA ₁ signal is held at H or L at the time of destruction. At the gate G13 of the failure detection section 29,
The AUTO signal and the CA ₂ signal of the counter C-3 of the measurement interval control circuit 24 are applied, and the output becomes L at about 2 minutes from the start of measurement. Then, after about 6 more minutes, when the output Q _T of the 8 minute clock pulse generation circuit B-2 becomes L, the gate G
14 outputs a fuel stop signal of H level when the conditions are met, the fuel relay FUEL is activated, and as the fuel supply is stopped, the operation of the heat source in the dryer is eventually stopped. On the other hand, if the moisture content of the material to be dried is sufficiently higher than the target moisture content at this time, the output Q of the flip-flop FF-4 of the moisture content storage circuit 30 becomes L, and the conditions for the gate G-16 are not satisfied. Air blowing and circulation by the blower relay FAN are continued, thereby preventing quality changes due to stuffiness of the dried material during the initial stage of drying when the moisture content of the dried material is high. On the other hand, when the material to be dried is dried to a state close to the target moisture content and the moisture content is low, the output Q of the flip-flop FF-4 of the moisture content storage circuit 30 becomes H, and the output of the gate G-16 becomes H. When the conditions are met, the output becomes L, so a stop signal is also sent to the blower relay FAN. Therefore, in the dryer, all heating, air blowing, and circulation are stopped, thereby preventing dynamic cracking due to rapid moisture absorption of the material to be dried. Note that it is appropriate to issue the alarm in conjunction with the operation of the fuel relay FUEL, and a delay element may be provided to delay the operation when the blower relay FAN is operated. Figure 4 shows a time chart during measurement, and the dotted line indicates coupling failure during three measurements.
This is the case when a failure is detected. The functions and operations from the start of drying to the end of drying based on FIG. 3 explained above are explained more clearly with the block diagram of FIG. 5 and the flowchart of FIG. 6.

【Effect of the invention】

As is clear from the above explanation, according to the present invention, the moisture content of the material to be dried is detected at the time of a failure (abnormality) in the sequence control, and subsequent control is performed separately for high moisture and low moisture cases. This prevents the shell from cracking due to rapid moisture absorption when the moisture content is low, so the quality of the dried material can be maintained without deterioration compared to conventional equipment. Furthermore, since the same control system as the conventional one is used and a water content storage circuit is added thereto, it is structurally simple and can be easily assembled into ready-made products.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of an automatic moisture content measuring device to which the present invention is applied, Fig. 2 is a cross-sectional view of Fig. 1, and Fig. 3 is a circuit diagram showing an embodiment of a safety device. , FIG. 4 is a diagram showing a time chart at the time of failure detection, FIG. 5 is a block diagram of the circuit, and FIG. 6 is a flow chart thereof. DESCRIPTION OF SYMBOLS 1... Motor, 2... Rotating shaft, 3... Coupling, 4... Gear, 5... Stopper, 6... Upper electrode, 7... Housing, 8... Sleeve, 9... Bracket, 10 ...Nut, 11 ...Mounting screw, 1
2, 17...Lead wire, 13...Protrusion, 14...
Groove, 15... Lower electrode, 16... Sample plate, 18...
...Shaft, 19...Gear part, 20...Gear mechanism, 21
... Measuring section, 22 ... Integrating circuit, 23 ... Comparison circuit, 24 ... Measurement interval control circuit, 25 ... Measurement number counting circuit, 26 ... Measurement flag circuit, 27 ...
2-second clock pulse generation circuit, 28...Two-stage cutoff flag circuit, 29...Failure detection section, 30
...Moisture content memory circuit.

Claims (1)

[Claims] 1. A measurement unit that automatically measures the moisture content of grain to be dried during drying in a grain dryer and outputs a measured value signal, and a setting that corresponds to a manually set target moisture content value for drying. A target moisture content setting unit that outputs a value signal inputs and compares the measured value signal and the set value signal, and outputs a drying stop signal when the moisture content value of the grain to be dried reaches the target moisture content value. In addition, in an automatic moisture content measuring device comprising a measurement control unit that performs various sequence controls of automatic measurements, a failure detection unit that outputs a safety stop signal when an abnormal state of the sequence control of the measurement control unit is detected during automatic measurement. and when the safety stop signal is input when the measured value is within a predetermined high moisture content value range, at least the fuel supply to the burner of the dryer is stopped and the drying fan is continuously controlled; When either the drying stop signal or the safety stop signal when the measured value is in a predetermined low moisture content range is input, at least the fuel supply to the burner of the dryer and the drying air fan are controlled to stop. An automatic moisture content measuring device characterized by being provided with a dryer stop section.