JPH08233464A - Discharge valve controller for circulation type grain drier - Google Patents

Abstract

PURPOSE: To provide a discharge valve controller for a circulation type grain drier which is applicable even for a motor with a rapid change in load, such as a slower motor. CONSTITUTION: Motors 17, 19 and 26 for driving a grain conveying/discharging means to circulate and discharge grains in a drier are provided with current detectors 28, 29 and 30 to detect load currents. A computing means 35 is arranged to calculate each mean value of respective current values detected by the current detectors 28, 29 and 30 and a comparison means 35 is arranged to compare the individual current value calculated by the computation means 35 with an overload criterion value set previously for the motor involved. A discharge valve motor control means 37 is provided to increase or decrease an outflow value from an discharge valve when the mean current value of any motor exceeds the overload criterion value by the comparison means 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge valve control device for a circulating grain dryer.

[0002]

2. Description of the Related Art A circulating grain dryer comprises a storing section, a drying section and a grain collecting section. The grain collecting section communicates with a storing section through a grain lifting machine to form a circulating grain stroke, and a conveyor. It is driven by an electric motor, a grain elevator motor, a discharge valve motor, and the like. Then, after the grain put into the storing section is dried in the drying section, it is intermittently supplied to the grain collecting section by the discharge valve provided below the drying section, and the grain collecting section transfers the grain to the storing section. After being charged, the circulation is repeated until a predetermined water content is reached.

In the circulation type grain dryer as described above,
A current transformer (CT) as an overload detection sensor is provided in each motor that drives the carrier machine, the grain elevator, the discharge valve, the wind blower, and the discharge thrower. The current transformer detects the load current value of each motor and inputs the detection signal to the control device. When the control device determines that the detected current value is equal to or more than the overload current value, the electromagnetic switch interposed in the power supply of the motor is opened by the output signal from the control device, and the operation of the motor is stopped. As a result, burnout due to overload is prevented.

In Japanese Unexamined Patent Publication (Kokai) No. 5-34063, the current transformer as described above is used to prevent interruption of grain circulation work and discharge work due to overloading of the grain elevator motor, and to recycle grain. Discharge valve controller for a circulating grain dryer to stabilize quantity is disclosed. This configuration is described as follows.
A drive motor for rotating the discharge valve, a current detector interposed in the power source of the motor for driving the grain elevator, and a current value detected by the current detector and an upper limit or a lower limit set current value are compared, A control device for controlling the operating time or the rotation speed of the discharge valve driving motor when the set current value is continuously detected for a predetermined time is provided.

Next, the operation of the above discharge valve control device will be described with reference to FIG. FIG. 9 is a time chart showing the load of the motor. In FIG. 9, for example, the current value (rated current value) during normal operation of the motor for driving the grain elevator is 100
%, The upper limit of the load current value is set to 120% of the rated current value, and the lower limit of the load current value is set to 90% of the rated current value. Then, the control of the discharge valve is performed as follows.
When discharging or circulating work, if the detected current value (solid line waveform) of the motor for driving the grain elevator exceeds the upper limit of the load current value for a predetermined time, the operation of the discharge valve motor is stopped,
Suspend the operation of the discharge valve. Then, the stopped state is continued until the load state of the motor for driving the grain elevator is returned to the rated current value, and when the rated current value is restored, the operating time of the discharge valve is reduced. This reduces the amount of grains discharged per hour and prevents the motor for driving the grain elevator from being overloaded. Further, when the detected current value of the motor for driving the grain lifting machine falls below the lower limit of the load current value for a predetermined time, the operation time of the discharge valve is increased to increase the discharge amount of grain per hour.

[0006]

In the conventional discharge valve control device described above, the discharge valve operating time is controlled by detecting the current value of the motor for driving the grain elevator whose load fluctuation is relatively gentle. are doing. However, in the case of a motor such as a thrower motor with a large load fluctuation, the detected current value (waveform of the broken line) rapidly and frequently exceeds the load current value.
The control of the operating time of the discharge valve was also excessively performed. For this reason, the amount of grains circulated becomes unstable, and there is a risk that uneven circulation occurs when grains are circulated and dried, resulting in overdried rice. Further, if the detected current value suddenly exceeds the load current value, it may be judged that the thrower motor is overloaded and the discharging work may be interrupted.

In view of the above problems, it is a technical object of the present invention to provide a discharge valve control device for a circulation type grain dryer that can be applied to a motor such as a thrower motor whose load changes greatly.

[0008]

In order to solve the above-mentioned problems, the present invention has a tempering tank at the upper part and a dryer main body at the lower part, and the dryer main body is provided with grains from the tempering tank. Is provided with a grain drying chamber for drying while flowing down, and a discharge valve for feeding the grains from the grain drying chamber, and the circulating grain drying process by connecting the dryer body and the tempering tank with a grain lifting machine. In the circulation type grain dryer which has formed the above, a current detector for detecting a load current is provided in each motor for driving the grain conveying / discharging means for circulating and discharging the grain in the dryer, and the current is detected by each current detector. Calculating means for calculating an average value of the respective current values, comparing means for comparing the respective average current values calculated by the calculating means with an overload judgment value preset in the motor, and the comparing means One of the average current value of the motor is provided and a discharge valve control means for causing the increasing of the outflow from the discharge valve Gensa when exceeded the overload judgment value, it took technical means of.

Further, the grain conveying / discharging means includes a lower screw conveyor for transferring the grains discharged from the discharge valve, a fried machine for connecting the dryer body and the tempering tank, and the fried machine. It may be configured with a discharging thrower provided in the grain discharging path.

[0010]

[Function] When the grain stuck in the tempering tank of the circulation type grain dryer flows down through the grain drying chamber provided in the dryer main body, the drying wind blasted by the hot air generator causes the grain drying chamber. To be dried. In this circulation type grain dryer, the detected value from the current detector interposed in each motor for driving the grain conveying / discharging means is inputted to the calculating means, and the average value of the respective current values detected in the calculating means. Is calculated. Then, each average current value is input to the comparison means and compared with the overload determination value preset in the motor. Next, when the average current value of any of the motors exceeds the overload determination value by the comparison means, the discharge valve motor control means is operated to increase or decrease the outflow amount of the discharge valve.

[0011]

An embodiment of the present invention will be described with reference to the drawings.
1 and 2, the circulating grain dryer 1 includes a dryer main body 2 and a tempering tank 3 mounted on the dryer main body 2, and the dryer main body 2 and the tempering tank 3 are provided on one side thereof. The grain lifting machine 4 to be connected is erected to form a circulating grain stroke. In the dryer main body 2, a grain drying chamber 5 for drying the grains while flowing them from the tempering tank 3 is formed by an air-permeable mesh plate. Then, a space surrounded by the grain drying chamber 5 is formed as a hot air supply chamber 6 in a substantially central portion of the dryer main body 2, and a space surrounded by the side wall of the dryer main body 2 and the grain drying chamber 5 is exhausted. An exhaust fan (not shown) is provided on the terminal side of the exhaust chamber 7.

The lower ends of the grain drying chamber 5 are joined to each other, and a long discharge valve 8 for feeding the grains out of the grain drying chamber 5 is horizontally installed at the joining portion. The discharge valve 8 has a cutout 9 over the entire length, and when the discharge port 10 of the grain drying chamber 5 and the cutout 9 match, the grain flows into the discharge valve 8 and is discharged by the rotation of the discharge valve 8. It

Below the discharge valve 8, a grain collecting trough 11 is arranged in a funnel shape, and a lower screw conveyor 12 as a lower conveying device is laterally provided at the bottom of the grain collecting trough 11. The conveying end portion of the lower screw conveyor 12 is provided so as to project in front of the dryer main body 2 and is connected to the grain elevator 4 to communicate with the tempering tank 2. A downflow gutter 13 is connected to the upper part of the grain elevator 4, and a switching valve 14 is connected from the downflow gutter 13.
Through the upper screw conveyor 15 as an upper conveying device and the grain discharge path 16.

The grain discharge passage 16 has a thrower motor 17 in it.
Is connected to a lowerer 18 that drives the grain discharged from the grain discharge path 16 to the outside of the dryer 1 to a position further away from the dryer 1 (a position higher than the dryer 1). .

Next, the above grain elevator 4, discharge valve 8, lower screw conveyor 12, upper screw conveyor 15
The drive system of the thrower 18 will be described. FIG. 3 is a schematic diagram showing each drive system. In FIG. 3, the fried machine motor 19 provided on one side of the fried machine 4 has an upper screw belt 20.
The upper screw conveyor 15 is driven via the upper screw conveyor 15, and the upper screw pulley 21 of the upper screw conveyor 15 drives the fried machine 4 via the fried machine belt 22. The discharge valve motor 23 rotates the discharge valve 8 via the chain 24, and the thrower motor 17 drives the thrower 18 via the thrower belt 25. Then, the machine motor 26 drives the lower screw conveyor 12 via the lower screw belt 27.

Next, a motor control circuit will be described with reference to FIG. Current detectors (CT) 28, 29, 30 for detecting a load current are interposed in the respective power sources of the slower motor 17, the grain elevator motor 19, and the motor 26 of the present machine, and the current detectors 28, 29, 30 are respectively It is input to the AD converter 33 via the rectifier 31 and the amplifier 32. The AD converter 33 communicates via the input / output circuit 34 with the CPU 35, which is composed of arithmetic means and comparison means. CPU3
The calculating means in 5 calculates the average value of the respective current values detected by the current detectors 28, 29, 30 and the comparing means calculates the respective average current values and the overload judgment value preset in the motor. To compare. And CPU3
The output signal 36 from 5 communicates with the discharge valve motor control means 37 via the input / output circuit 34. The discharge valve motor control means 37 communicates with the discharge valve motor 23 to increase or decrease the amount of grains discharged from the discharge valve 8.

Reference numeral 38 is a storage device composed of a ROM and a RAM, and stores the overload determination value set for each of the motors 17, 19, and 26. Also, reference numeral 39
Is a feed switch, reference numeral 40 is a drying switch, and reference numeral 41 is a discharge switch.

Next, the operation of the above configuration will be described with reference to FIG.
Also, description will be made with reference to FIG. FIG. 5 is a flowchart showing a process when discharging the grain from the dryer.

At step 100, the discharge switch 41 is turned on.
Then, the machine motor 26 that drives the grain conveying / discharging means
And the grain elevator motor 19 is driven (step 10).
1). Then, in step 102, a timer that waits for, for example, 2 seconds is activated so as not to sample the inrush current when the motor is started. Next, in step 103, it is determined whether or not the discharge thrower 18 is attached to the dryer. If the discharge thrower 18 is included, the thrower motor is driven in step 104 to include the discharge thrower 18. If not, the process goes directly to step 105. In step 105, the switching valve 14 is switched from the tight side to the discharge side, and the grain discharge path 16 is opened. Then, in step 106, as in step 102, a timer that waits for, for example, 2 seconds is activated, and when the discharge valve motor 23 is driven in step 107, the grain discharge operation is performed. When the motors 17, 19, 26 and 23 are driven by the above process,
In the next step 108, the averaging process of the current values detected by the current detectors 28, 29, 30 is performed. This current value averaging process will be described with reference to FIGS. 6 and 7. Since the current detectors 28, 29, 30 perform the same processing, the current detector 28 (hereinafter C
T ₁ ). When CT ₁ detects the current of the motor 17 in step 109, step 11
The sampling timer of 0 is activated, and when the sampling time has elapsed, step 111 is reached, and the current value of CT ₁ is taken into the CPU 35. And step 112
Then, the current value taken in by the CPU 35 is stored in the storage device (RA
M) 38. Next, in step 113, the maximum value and the minimum value of the current values continuously detected by CT ₁ are calculated (see FIG. 7). That is, the current measured value of CT ₁ is compared with the previous measured value stored in the storage device 38, and if the current measured value is larger than the previous measured value, the current value is the maximum of CT ₁ . Value and None (Step 11
4) If the current measured value is smaller than the previous measured value,
The previous value is set as the minimum value of CT ₁ (step 115). Then, one cycle of the output waveform is sampled while updating the maximum value and the minimum value in the one cycle section of the output waveform (step 116). Next, at step 117, 1
The interval of the cycle is divided into n equal parts, and in step 118, the value of CT ₁ in the equally divided period is integrated. Then, in step 119, the integrated value CT of step 118 is divided by n to calculate the average value of the detected current value of CT ₁ for one cycle.

By the way, the step 116 is 1 for the output waveform.
Although the calculation of the cycle is determined while updating the maximum value and the minimum value, the on-time and stop time of one cycle of the discharge valve that rotates intermittently may be considered as one cycle of the output waveform. That is, since the load is also applied to the thrower motor 17 in response to the intermittent discharge of grain from the discharge valve, the cycle of the output waveform becomes equal to the time of one cycle of the discharge valve (see FIG. 7).

After the averaging process of the detected current value is completed, the process goes to step 120 in FIG. In step 120, the averaged current value and the overload determination value preset for the motor are compared. Then, when the averaged current value exceeds the overload determination value, the process goes to step 122, and a change is made to lengthen the discharge valve interval. That is, when it is determined that the load is overloaded, the discharge valve motor control unit 37 outputs the stop time of the discharge valve to 1
When it is extended for about a second (see FIG. 8), the amount of grain discharged from the discharge valve 8 is reduced and the overload of the motor is eliminated.
If the averaged current value does not exceed the overload determination value, the process goes to step 121, and the discharge valve interval is shortened. That is, when the discharge valve control means 37 shortens the stop time of the discharge valve by about 1 second, the amount of grain discharged from the discharge valve 8 is increased and the rated current value of the motor can be utilized to the maximum extent.

Next, step 123 and step 124.
Is provided with a timer having a delay time of 6 seconds, and in steps 125 and 126, the current detectors 28, 29, 30 are again used.
The current value detected by the above is averaged, the overload is determined in step 127, and the interval of the discharge valve is changed in steps 128 and 129 as described above. On the other hand, if the second overload is determined in step 130, the CT error count in step 131 is incremented, and if the CT error count is determined to be 0 or more in step 132, a motor abnormality display is displayed in step 133. At the same time, the driving of the motor is stopped.

As described above, in this embodiment, the load current values of the motors 17, 19, 26 for driving the grain conveying / discharging means are detected by the current detectors 28, 29, 30 and the current detector 28 is detected. , 29, 30, a calculation means 35 for calculating an average value of respective current values detected, and a comparison for comparing each average current value calculated by the calculation means 35 with an overload determination value preset in the motor. The means 35 and the discharge valve control means 37 for increasing / decreasing the outflow amount from the discharge valve 8 when the average current value of any one of the motors 17, 19, 26 exceeds the load judgment value by the means 35 and the comparing means 35. The discharge current is interrupted because the detected current value is averaged and compared with the overload determination value even in the case of a motor such as the thrower motor 17 in which load fluctuations are severe. Without, it becomes possible to perform discharge operations by utilizing the rated output of the motor to the maximum.

[0024]

According to the circulation type grain dryer of the present invention, a current detector for detecting a load current is provided in each motor for driving grain conveying / discharging means for circulating / discharging grains in the dryer, A calculating means for calculating an average value of respective current values detected by the respective current detectors, and a comparing means for comparing the respective average current values calculated by the calculating means with an overload judgment value preset in the motor. , A discharge valve motor control means for increasing / decreasing the outflow amount from the discharge valve when the average current value of any one of the motors exceeds the overload determination value by the comparison means. Even in the case of a motor in which the load fluctuation is severe, the detected current value is averaged and compared with the overload judgment value, so the discharge work is not interrupted and the rated output of the motor is not interrupted. It has become possible to carry out the evacuation work full advantage.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire circulating grain dryer.

FIG. 2 is a front sectional view of a circulation type grain dryer.

FIG. 3 is a schematic view showing each drive system of a circulation type grain dryer.

FIG. 4 is a block diagram showing a motor control circuit of the present invention.

FIG. 5 is a flowchart showing a discharge process and a discharge valve control according to the present invention.

FIG. 6 is a flowchart showing a process of averaging detected current values according to the present invention.

FIG. 7 is a time chart showing the correspondence between the output waveform of the detected current value and the discharge valve cycle.

FIG. 8 is a time chart showing the change of the discharge valve stop time.

FIG. 9 is a time chart showing a motor load of a conventional exhaust valve control device.

[Explanation of symbols]

 1 Circulating Grain Dryer 2 Dryer Main Body 3 Conditioning Tank 4 Grain Lifter 5 Grain Drying Room 6 Hot Air Supply Room 7 Exhaust Chamber 8 Exhaust Valve 9 Notch 10 Discharge Port 11 Grain Gutter 12 Lower Screw Conveyor 13 Downflow Gutter 14 Switching valve 15 Upper screw conveyor 16 Grain discharge path 17 Thrower motor 18 Thrower 19 Lifter motor 20 Upper screw belt 21 Lower screw pulley 22 Lifter belt 23 Discharge valve motor 24 Chain 25 Thrower belt 26 This machine motor 27 Lower screw Belt 28 Current detector 29 Current detector 20 Current detector 31 Rectifier 32 Amplifier 33 AD converter 34 Input / output circuit 35 CPU 36 Output signal 37 Discharge valve motor control means 38 Storage device 39 Strain switch 40 Drying switch 41 Discharge switch 42 Scattering 43 moisture measurement device

Claims (2)

[Claims] 1. A grain-drying chamber in which a tempering tank is provided in an upper part and a dryer body is provided in a lower part, and the grain is dried while flowing down the grain from the tempering tank in the dryer body, and the grain. Provided with a discharge valve for feeding grains from the grain drying chamber, in the circulation type grain dryer forming a circulating grain drying process by connecting the dryer body and the tempering tank by a grain raising machine,
A current detector for detecting a load current is provided in each motor for driving a grain conveying / discharging means for circulating / discharging grains in the dryer, and an average value of respective current values detected by each current detector is calculated. And a comparison means for comparing each average current value calculated by the calculation means with an overload determination value preset in the motor,
A discharge valve motor control means for increasing / decreasing the amount of outflow from the discharge valve when the average current value of one of the motors exceeds the overload determination value by the comparison means is provided. Discharge valve control device for circulating grain dryer. 2. The grain conveying / discharging means includes a lower screw conveyor for transferring the grains discharged from the discharge valve, a fried machine connecting the dryer body and the tempering tank, and the fried machine. 2. A discharge valve control device for a circulation type grain dryer according to claim 1, comprising a discharge thrower provided in the grain discharge passage.