JPS6016576B2 - Automatic moisture content measuring device in dryer - Google Patents

Description

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

The present invention relates to a dryer that automatically measures the moisture content of grains (for example, paddy) or other materials to be dried, and stops the dryer when the target moisture content is reached. .

[Successful technology]

In a general dryer, a sample of the material to be dried is collected, the sample is crushed between a pair of electrodes, and the electrical resistance, capacitance, etc. between the electrodes are measured. In order to improve drying accuracy with such dryers, measurements are taken at appropriate intervals until the end of drying, and for each measurement, measurements are taken several times in succession and the average value is calculated. Drying is stopped when the average value reaches a set target.

Problem 1 to be Solved by the Invention In such a measuring device, if immature rice containing extremely high moisture content is mixed in, the measured value will fluctuate. When drying grains that are often contaminated with immature rice, the measured value will vary greatly depending on whether or not immature rice is introduced between the measurement electrodes. The degree of this is usually 3 near the dry finish.
%, and if such a measurement is performed once, for example, if the average value of 5 measurements is obtained, it will be approximately 0.0%.
This would result in a measurement error of 6%. Generally, such immature rice is removed during the preparation process after drying, and it is actually desirable to exclude it from the measured values. [Means for Solving the Problems] The present invention provides an automatic moisture content measuring device that periodically measures the moisture content of grain to be dried and stops operation of the dryer when the value reaches a target moisture content value. If an abnormal measurement value occurs when measuring something in an abnormal state, such as immature rice, by limiting it to a predetermined level, even if an abnormal moisture content is measured, the measurement error can be minimized. This feature is characterized by ensuring accuracy when automatically stopping.

【Example】

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 is a measuring device that crushes rice grains and measures electrical resistance, and generates a signal that is inversely proportional to this resistance; 2 is an integrating circuit; 3 is a measurement level comparison circuit; 4 is a measurement interval control circuit; 5 is a measurement count circuit, 6 is a measurement flag circuit, and 7 is a measurement flag circuit.
8 is a two-second clock pulse generation circuit, and 8 is a two-stage cutoff flag circuit. In the measuring machine, the sample pan is in the standby position, and the standby limit switch WTLS is open at that position.The sample pan is moved forward by the operation of the motor to collect the sample, and at the forward end, the limit switch FW is opened and stopped. Furthermore, after a certain period of time, the motor reverses,
Limit switch BW false opens at the backward end. When the power is turned on (start in Figure 4), the melon IT
The counter C-1 of the measurement count circuit 5 is set by the signal via the NOR gate G-1, and the count is set to 11. As a result, the output QD becomes high level (hereinafter referred to as "day") and an AUTO signal is generated. This AUTO signal is a signal indicating that automatic measurement is in progress, and allows counting to the measurement count circuit 5, permission to integrate to the integrating circuit 2, and measurement flag circuit 6.
It acts as a command signal for canceling the stop, etc. Also, setting the count to 11 is 12, 13, 14, 15 from now on.
, 0, and the AUTO signal is maintained until the measurement is completed five times. On the other hand, the flip-flop FF-1 of the measurement flag circuit 6 is cleared by the INIT signal, and its output Q becomes a low level (hereinafter referred to as L). Since the sample plate is in the standby position, the limit switch WT is open and the F
WLS and BWLS are closed. AU at gate G-A
Since this is prohibited by the L level of the TO signal, the output of gate G-2 is at high level. Therefore, gate G-
3 is turned on, motor forward rotation relay FWD is activated,
The motor rotates forward and the sample blood moves forward into the dryer. When limit switch FWLS is pressed and opened at the forward end, the input of gate G-2 becomes day, its output becomes L, gate G-3 is inhibited, relay FWD is deactivated, and the motor is stopped. On the other hand, due to the operation of the limit switch FWLS, the output of the negative input OR gate G-4 becomes day,
Clearing of the delay counter C-2 is canceled via the inverter 1-1, and counting of 2-second clock pulses output from the output Q of the free-running oscillator B-1 of the 2-second clock pulse generation circuit 7 is started. This 2-second clock pulse is a pulse signal set mainly to regulate the integration time of the integration circuit 2, which will be described later.
When the count reaches 8 (one streak elapsed), the output QD of the counter C-2 becomes the day, and the inputs of the gate G-5 both become the day, so the output becomes L. 16 counts (32 types/
When the output QD becomes L at the time (time), the output of the gate G-5 becomes DAY, the output Q of the flip-flop FF-1 of the measurement flag circuit 6 becomes DAY, and the output Q becomes L. Since limit switch BW melon is closed, gate G-
6, the inputs are both turned on, the relay BAK is activated, the motor is reversed, and the sample plate begins to move backward. In this way, after the sample dish moves forward and stops, the sample dish moves forward and stops for a certain period of time (32
The reason why it is retreated after the step (step/pass) is to ensure that the sample is collected onto the sample pan during that time. Due to the retraction of the sample dish,
Limit switch FWLS closes, delay counter C-2
Clear. When the limit switch BWLS is actuated and opened at the retreating end of the sample blood, gate G-6 is prohibited, BAK is deactivated, the motor is stopped, and the sample is simultaneously crushed between the electrodes. At the same time, the delay counter C-2 starts counting the output pulses of the 2-second clock generation circuit 7, similar to when the limit switch FWLS is opened. Counter C-
When 2 counts 8 (one current elapsed), its output QD becomes day and its output QA becomes L. On the other hand, since the limit switch BW is open, the inputs of the 3-input NAND gate G-7 are both positive, and its output is L, activating the switch circuit S-1 and closing the switch SW-1. Therefore, when the sample is crushed and the output of the measuring device 1 becomes sufficiently stable after one base sand elapses, the integrating circuit 2 starts integrating the output. When counter C-2 counts 9 (1 parent sand/elapsed), output A.
becomes H', the input conditions for 3-input gate G-8 are set,
Its output becomes L. This output L indicates that one measurement has been completed, and the signal is sent to the measurement flag circuit 6 via gate G-9.
The flip-flop FF-1 is reset, the motor forward rotation relay FWD is activated, the motor rotates forward again, and the sample blood begins to advance. Further, the signal is input to the counter C-1 of the measurement number counting circuit 5, and the count is counted by 1, and the count becomes 12, and the first measurement is completed. At the same time as the above counting, the output QA of the counter C-2 becomes the day, the output of the gate G-7 becomes the day, and the switch SW-1 opens.
The first integration is finished. When the sample dish moves forward, limit switch BWB closes.
Counter C-2 is cleared again. During the forward movement of the sample blood, the standby limit switch WT false is opened and the input to the gate G-A becomes "day", but since the gate G-A remains prohibited by the AUTO signal, the motor does not stop. That is, the counter C-1 is connected to the gates G-7 and G-8 to count the number of measurements, and the counter C-2 is connected to the gates G-7 and G-8 to control the integration circuit 2, measurement counting circuit 5, measurement flag circuit 6, etc. Each performs a counting operation to output an operation timing signal. The above operation is repeated, and the number of measurements is counted by the counter C-1 of the counting circuit 5. When the fifth measurement is completed, the count returns to 0, and the output QD becomes L. As a result, the inhibition of gate G-A by the AUTO signal is released, and when limit switch WT melon opens, gate G-A is released.
The output of A becomes L, and the output of gate G- through gate G-2.
3 is inhibited, relay FWD is deactivated, and the sample dish is stopped at limit switch WTB. Above 5
The integrated value of the measured values obtained by each measurement is compared with a comparison level in the comparator circuit 3. The comparison circuit 3 includes three comparison circuits F-1, F-2, F-.
3 is provided, F-1 has the lowest comparison level and becomes the target value, while F-3 and F-2 are made up of resistors R,, R2, and R3 so that they are higher than F-1. The pressure circuits are arranged one above the other at a predetermined distance from each other.
The integrated voltage is supplied to the inverting input of each comparator circuit by a voltage dividing circuit including resistors R4, VR, and R5. Furthermore, the reference voltage for each comparison level of the comparator circuit 3 is connected to the resistors R, , R2.
, R3 are connected in series to the voltage divider circuit.
This can be changed by changing the value of the resistor VR2 using S. That is, in order to select and set the target moisture content value, the user can change the overall comparison level of each comparison circuit up or down by changing VR2 using the rotary switch RS. Therefore, the voltage integrated by the integrating circuit 2 is compared by the comparator circuit, but as the integration progresses, the comparator circuit F-1 reaches the reference voltage in the vertices F-2 and F-3. When the integrated value becomes higher than each reference voltage, the output of each circuit goes to L level. In this case, if there is a lot of moisture, the level goes up to F-3, but if the moisture content is low, it goes to F-3 or F-2. does not become L and remains as day.For example, F-3 becomes day when the moisture content is 19% or less, F-2 becomes day when the moisture content is below 17%, and F-1 becomes day when the moisture content is below 15%.Each comparison The output of the circuit is applied to the inputs B, C, and D of the counter C-3 of the measurement interval control circuit 4, and is loaded when the carry output CA of the counter C-1 of the measurement number counting circuit 5 becomes L. The counter C-3 counts the pulses of the 8-minute clock pulse generation circuit B-2, and when returning from count 15 to 0, the carry output CA becomes L. .
For example, if the output of F-3 falls below 19%,
64 minutes are loaded at count 8, 32 minutes at count 12 when F-3 and F-2 become days, and 16 minutes at count 14 when all days are loaded. Therefore, a time is set depending on the moisture content at that time, and when the time elapses, the counter C-1 is loaded again by the carry output CA and the next measurement is started. Next, when the moisture content reaches the target value or less, all outputs up to the comparator circuit F-1 become "day". At this time, the output of F-1 (output COFF) is the first stage flip-flop FF of the two-stage cutoff flag circuit 8.
-2 is applied to the input D, and the carry output CA of the measurement count circuit 5 activates the flip-flop FF-2 through the gate G-10, and the output Q becomes the day, and the drying reaches the target value. Remember what you have achieved. 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 cutoff flag circuit 8 is determined. To D.
Output COFF and output Q of first stage flip-flop FF-2
is being applied, the flip-flop FF-3 is operated by the carry output CA of the measurement number counting circuit 5. Then, the output Q activates the fuel relay FUEL, and the fuel is stopped. After several minutes, the gate 11 is turned on by the output Q of the timer B-2, the blower relay FAN is activated, the blower is stopped, and the drying process is completed. At the same time, the measurement interval control circuit 4 is cleared and the automatic measurement function is stopped. The present invention provides such a device in which the comparator circuits F-1,
Flip-flops FF-4 and FF-5 are connected to the output of F-2, and each output Q is connected to an analog switch SW-2 and SW.
-3 is connected. Further, the amplifier circuit A-1 to the integrating circuit 2 is provided with a feedback circuit consisting of resistors R6, R7, R8, a comparator circuit F-4, and a diode D-1. The input of the comparison circuit F-4 is connected to the comparison circuit F-1 via the resistor R9 and the contacts of the switches SW-3 and SW-2.
The potentials at each point a, b, c of the reference voltage to 3 are selectively applied. Switch SW-2, SW-
3 are not operating, contacts d and e are closed, and the potential at point a is applied. When the water content becomes low, comparison circuit F-2 is activated and flip-flop FF is activated.
When the output of -5 becomes day, the switch SW-2 is activated and the contact f is closed. Therefore, the potential is switched to point b. Similarly, when the comparison circuit F-1 is activated, the switch SW-3
is activated, contact g closes, and the potential is switched to point c.
Thus, when the water content set by each comparison circuit is reached, the input of the comparison circuit F-4 is set to a potential that provides a slightly higher water content. Output of amplifier circuit A-1, that is, integration circuit 2
When the input to increases in the negative direction, it is divided by resistors R8 and R7, and this is compared with a reference potential at resistors R8 and R9. When the reference potential is exceeded, the output of the comparator circuit F-4 becomes a negative output, the diode D-1 becomes conductive, and is fed back to the amplifier circuit A-1. Thus, the amplitude is limited by the reference voltage, and the input to the integrating circuit is limited to a constant value. Conversely, when the output of amplifier circuit A-1 is small, comparison circuit F-4
The output of will be a positive voltage, diode D-1 will be non-conducting, and no amplitude limiting will occur. Therefore, the input to the integrating circuit is limited by the reference voltage, and abnormal measurement values are not integrated, so that measurement errors do not occur. In the embodiments described above, the amplitude limiting reference voltage changes as the water content decreases, but in the embodiment shown in FIG. 2, it is limited to one set voltage. Furthermore, in this embodiment, measured values of abnormally low water content are also restricted. That is, the resistors RI0, RI1,
R12, R13 and comparison circuits F-4, F-5 constitute a comparison circuit, and diodes D-1 and D-2 are connected to this to enable feedback. The reference voltage is given at a relatively high point h. When the input to the integrating circuit is high, diode D-1 is conductive as in the previous example, and when the input is low, diode D-2 is conductive, each limiting the amplitude. Based on the above-described FIG. 2, the functions and operations from the start of drying to the end of drying are explained more clearly with the flow chart of FIG. In addition, to explain the relationship with FIG. 2 in the block diagram of FIG. 3 which shows the above functions and operations in an easier-to-understand manner, the moisture content measuring section includes a measuring device 1, limit switches WTLS, FWLS, BW. is the measurement interval control circuit 4
, measurement count circuit 5, measurement flag circuit 6, 2-second clock pulse generation circuit 7, gates GI to GI0, relay 1F
It consists of WD, BAK, etc. The average value calculation section consists of an integrating circuit 2 and a switch circuit S-1, the target moisture content setting section consists of a rotary relay switch RS and a resistor VR2, and the comparison section consists of a measurement level comparison circuit 3, and a storage section. is composed of flip-flop FF-4. In addition, the limiting portion includes a resistor R,
o, R rivers R, 2, R, 3, comparator circuits F-4, F-5, and diodes D-1, D-2.
Consists of etc. Further, the dryer stop section includes a two-stage cutoff flag circuit 8, relays FUEL, FAN, and the like. According to this block diagram, the configuration, function, operation, etc. of the present invention can be more easily understood.

【Effect of the invention】

As is clear from the above, according to the present invention, the output of the target moisture content setting section and the output of the average value calculation section are compared, and when the difference between the two becomes equal to or less than a predetermined value, the first signal is output. a comparison section, a storage section that outputs an input limit signal after inputting and storing the first signal of the comparison section, and a storage section that is connected between the measurement section and the average value calculation section and inputs the input limit signal of the storage section; Since the structure includes a limiting section that operates when the drying temperature reaches the target moisture content value and limits the output of the measuring section to within a predetermined value relative to the output of the target moisture content setting section.
Even if the measuring section measures an abnormal moisture content value due to immature rice, the limiting section operates to limit the output of the measuring section to within a predetermined value relative to the output of the target water rate setting section. It is possible to reduce measurement errors due to immature rice compared to the case where there is no dryer, and it is possible to stop the dryer while ensuring stopping accuracy.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing another embodiment, FIG. 3 is a block diagram thereof, and FIG. 4 is a flowchart thereof. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A measuring section that measures the moisture content of the grain to be dried multiple times at a predetermined period and outputs each of these moisture content values, and inputs the output of each of these measuring sections and calculates the average value. an average value calculation section that outputs the average value of the lever; a target moisture content setting section for which a target moisture content value is set by the user and outputs the set value; The output of the value calculation section is compared, and when the difference between the two becomes less than a predetermined value, the first signal is sent, and when the output of the average value calculation section becomes less than the output of the target moisture content setting section, the first signal is sent. a comparator that outputs the second signal, and a second comparator of the comparator.
a dryer stop section that inputs the first signal of the comparison section and outputs a dryer stop signal; a storage section that inputs and stores the first signal of the comparison section and then outputs an input limit signal; and the measurement section and the average value. a limiting section connected between the calculating section and activated when the input limiting signal of the storage section is input to limit the output of the measuring section to within a predetermined value with respect to the output of the target moisture content setting section; An automatic moisture content measuring device for a dryer, characterized by: