JPH0827134B2 - Grain drying method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a grain drying method for drying rice and the like immediately after harvesting to a predetermined moisture value.

[Conventional technology]

Conventionally, a tempering tank is installed on the drying section,
This tempering tank and drying section are connected by a bucket elevator to form a grain circulation path, and a burner as a hot air generator, a moisture meter that measures the moisture value of grain at regular intervals, and a moisture value based on the moisture value are used. In a grain dryer that is equipped with a control unit that adjusts the hot air temperature so as to perform drying according to a preset standard drying rate (drying loss rate), while grain flows from the tempering tank to the drying unit (about 10 minutes) is exposed to the hot air from the burner and undergoes a drying action, and the grains flowing out of the drying section are returned to the tempering tank by a bucket elevator and tempered (tempered). It is formed so that the drying progresses. In addition, it is generally formed such that the drying speed is relatively high when the water content is high and the risk of cracking is low, and the drying speed decreases as the drying progresses. For example, if the grain moisture is S, when S ≧ 24.0, 1.25% / H, 24.0> S ≧ 21.0
When 1.05% / H, when 21.0> S ≧ 19.0, 0.95% / H
When H, 19.0> S ≧ 17.0, 0.75% / H, 17.0> S ≧ 16.
0.50% / H when 0, 0.45% / H when 16.0> S ≧ 15.0
Each is stored as H in the memory of the control unit.

[Problems to be solved by the invention]

By the way, at the above standard drying speed,
The relationship between water and time when 4.5% of raw rice is dried up to 15.0% is shown in an easy-to-understand manner as shown in Fig. 4 (note that the time for one cycle of paddy is 2 hours).

According to this, the moisture content of the paddy that has undergone the drying action of the fifth cycle is 15.4%, and the standard drying rate of the sixth cycle is 0.9%, so the paddy that has passed through the sixth cycle is dried to 14.5%. , The burner is stopped after receiving the moisture measurement by the moisture meter,
Drying will be completed. Although the finished moisture value changes depending on the initial moisture content of raw rice, which is the raw material, it is rare that the finished moisture value is achieved according to the target finish moisture value (15.0%), and in many cases, it is finished as over-dried rice that is below the finished moisture content. become. In the previous example, 1 in the 5th cycle
There was a problem that the paddy which had been 5.4% became 14.5 at the 6th cycle, resulting in a difference of 0.5 with the target finishing moisture (15.0%).

In view of this point, the present invention has a technical object to provide a grain drying method capable of finishing according to a target finish moisture.

[Means for solving problems]

In order to achieve the above object, the present invention is a so-called circulation type grain dryer, in which a measured drying speed is controlled by controlling the hot air temperature so as to follow the already set reference drying speed, the drying proceeds. At the time when the moisture meter detects a predetermined moisture value near the target finish moisture value, the predicted moisture value for one cycle of the grain is calculated based on the drying speed at this time, and this predicted moisture value determines the target finish moisture value. When it is below the range, the drying is performed at a finishing drying rate lower than the standard drying rate.

[Action and effect]

Drying is performed while making the current drying speed follow the reference drying speed set according to the moisture value, and the moisture value detected by the moisture meter is less than or equal to the predetermined moisture value automatically set near the target finish moisture value. At this time, the expected moisture value when the grain circulates once is calculated based on the drying speed at this time, and if this value is below the target finish moisture value, then the drying should be stopped according to the target finish moisture value. The drying speed is changed to be smaller than the reference drying speed, and so-called finish drying control is performed.

As a result, at the time of the final circulation, the target finish moisture value does not fall below the target finish moisture value and overdrying occurs, and it is possible to always finish according to the target finish moisture value.

Example of Invention

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, a grain dryer 1 is composed of a drying section 2 serving as a base and a tempering tank 3 mounted on the drying section 2, and a lower portion horizontally provided in a grain collecting trough 4 at the bottom of the drying section 2. A bucket elevator 7 connects the transporting end portion of the screw conveyor 5 and the transporting start end portion of the upper screw conveyor 6 provided above the tempering tank 3. Further, a feeding hopper 8 equipped with a screw conveyor is connected to the supply section of the bucket elevator 7, and a discharge chute 10 leading to the outside is provided in the discharge section in a branch from the upper screw conveyor 6. And
A scatterer 9 is rotatably suspended at the end of conveyance of the upper screw conveyor 6.

Next, the drying unit 2 will be described. The drying unit 2 is formed rigidly as a base on which the tempering tank 3 is mounted, and inside the drying unit 2, a four-layer drying chamber 14 and a hot air chamber 15 and an air exhaust chamber 16 sandwiching the drying chamber 14 are provided. That is, four layers of grain flow-down passages 18A to 18D whose upper ends are connected to the lower ends of the tempering tank 3 and whose lower ends face the inside of the grain collecting trough 4 are arranged in parallel, and most of the grain flow-down passages 18A to 18D are perforated. It is made of a wall to form the drying chamber 14. Then, the rotary valves 17 are attached to the lower ends of the grain flow paths 18A and 18B and the lower ends of the grain flow paths 18C and 18D, respectively, and the rotation of the rotary valve 17 causes the grains in the tempering tank 3 to move.
A through 18D (drying room 14) is made to flow down and is formed so as to flow out into the grain collecting trough 4. The hot air chamber 15 communicates with the burner box 25 provided on the front surface of the grain dryer 1, and the hot air chamber 15 also has an exhaust chamber.
Reference numeral 16 communicates with an intake hole of a fan (not shown) provided on the rear surface.

Next, the burner 28 will be described with reference to FIG. The burner 28 is a pressurized spray gun-type burner for burning blue flame, and a fuel nozzle 31 connected to an electromagnetic pump 30 via an oil feed pipe 29 is horizontally installed in a blower pot 32. The fuel nozzle 31 is composed of an electromagnetic coil, a plunger, a nozzle opening, and a rod (not shown) for opening and closing the nozzle opening, and the like. When the electromagnetic coil is energized and excited, the plunger is pulled, and the nozzle opening The rod that closes the cylinder moves and fuel is discharged from the nozzle port. Therefore, the longer the energization time of the electromagnetic coil, the longer the opening time of the nozzle opening, and the more the fuel spray amount increases.

Combustion tube 33 is provided in connection with blower pot 32.
A tapered vaporization tube 35 is provided in the interior of 33, and the fuel nozzle 31 and the tip of the ignition electrode 40 face the base of the vaporization tube 35. On the other hand, the other end of the vaporization cylinder 35 is connected to a vaporization dish 44 via a gas acceleration pipe 42. The tip of a combustion state detection rod (frame rod) 48 is made to face the vicinity of the vaporization tray 44, and the combustion state detection rod 48 is connected to a burner arithmetic control unit 61. Further, the burner arithmetic control device 61 is a combustion nozzle 31,
The ignition transformer 41, the electromagnetic pump 30, the burner fan motor 52 of the burner fan 50 that blows air into the blower pot 32, and the tachogenerator 53 that detects the rotation speed of the motor 52 are communicated.

A control box 55 is provided adjacent to the burner box 25 containing the burner 28. On the front wall of the control box 55, in addition to the power switch and other operating switches, the type-specific switch 56, the overhang amount switch 57 and the finishing moisture setting switch 58, and the moisture value, hot air temperature and time until the end of drying are displayed moment by moment. A digital panel meter 59 or the like is provided.

And, in the control box 55, the grain dryer 1
ON / OFF of each electric motor (for bucket elevator, rotary valve, screw conveyor, etc.), setting of target temperature to make the drying speed in progress follow the reference drying speed, finish moisture setting When the target finish moisture value set with the switch 58 exceeds a certain value (eg, + 2%), the moisture value is set as a point for shifting to the finish drying rate (control), and various safety devices ( A central processing unit (commonly known as a main microcomputer) 60 that monitors the extinguishing device, wind pressure sensor, safety switch at the bottom of the bucket elevator, etc. is installed, and a combustion start signal and combustion level signal (target) from the central processing unit 60. Burner 28 to get temperature
(A signal indicating how much the amount of combustion of the burner is set) electrically and proportionally controls the energization time of the fuel nozzle 31 and the rotation speed of the burner fan motor 52 to adjust the hot air temperature. Built-in popular name burner controller). In other words, the central processing unit 60 is a product-specific switch mounted on the front of the control box 55.
56, a swelling amount switch 57, a finishing moisture setting switch 58 and a digital panel meter 59, and a moisture meter 62 for measuring the moisture content of dried grains at predetermined intervals and a temperature sensor 63 for detecting the temperature of hot air, Further, various operation switches (not shown) are contacted.

The sample inlet of the moisture meter 62 is the sample channel 64.
Is connected to the gutter bottom of the upper screw conveyor 6 by
Vibrator (not shown) installed in the detector of the moisture meter 62
The grain value in the upper screw conveyor 6 is taken in by the driving of, the capacitance is measured, and the moisture value of the sample is calculated after adding the temperature correction and the weight correction by measuring the volume weight. It is formed so that the moisture values of the batches are averaged and displayed on the digital panel meter 59. Further, the temperature sensor 63 is provided in the air blowing chamber 15 of the drying unit 2.
It is installed inside.

On the other hand, the burner arithmetic control unit 61 is a central arithmetic control unit.
Connected to 60, combustion nozzle 31, ignition transformer 4
1, connected to the electromagnetic pump 30, the burner fan motor 52, the rotation sensor 53 of the burner fan 50, and the combustion state detection rod 48.

The specific operation of the above embodiment will be described below. When the "hanging button" switch on the front wall of the control box 55 is turned on and the grain to be dried, for example, raw rice is put in from the hopper 8, the paddy rice is conveyed by the bucket elevator 7 and the upper screw conveyor 6, and scattered. While being scattered at 9, it is stretched into the tempering tank 3 in a substantially flat shape.

Before turning on the "Dry button" switch, set the product type switch 56 to "Rice" and the amount of swelling switch 57 to the number of stones actually squeezed, and finish moisture setting switch 58.
To set a desired finishing moisture value, for example, 15.0%.

When the "drying button" switch is turned on to start the drying operation, the fan provided on the rear wall of the drying unit 2 is driven and the electric motor (not shown) for intermittently operating the pair of rotary valves 17 is operated. ON time depends on the product type switch
56 and the amount of swelling switch 57 determine the appropriate circulation speed according to the type and the amount of swelling.

Grain flow down path 18A ~ 1 driven by rotary valve 17
The unhulled rice that has flowed down 8D and dropped into the grain collecting trough 4 is conveyed by the lower screw conveyor 5, the bucket elevator 7 and the upper screw conveyor 6 and returned to the tempering tank 3 while being scattered by the scattering plate 9. In the same manner, the circulation of paddy rice continues in the same manner, and the paddy rice is dried in the drying chamber
When passing through the ventilation chamber 15, it passes from the drying chamber 14 to the exhaust chamber.
It is exposed to the hot air passing through 16 and mainly deprives the rice husks of water. In the tempering tank 3, the moisture of the brown rice inside the rice husk is absorbed by the rice husks in the tempering tank 3, the water content of the rice husks and the water content of the brown rice are averaged (this is called tempering), and the rice husks are dried again. The process of drying the rice husks in step 1 is repeated.

On the other hand, by turning on the "dry" button switch,
The burner 28 starts burning. That is, the combustion start signal from the central processing unit 60 and the combustion level signal at the time of ignition
When L ₁ is input to the burner arithmetic control unit 61, the burner arithmetic control unit 61 drives the burner fan motor 52, and when the rotation of the burner fan 50 stabilizes, the ignition transformer
The pressure of 41 is increased, the ignition electrode 40 is sparked, and the electromagnetic pump 30 and the fuel nozzle 31 are activated almost at the same time. The fuel nozzle 31 discharges fuel (kerosene) at a flow rate of, for example, 2.5 l / H by determining the energization time to the electromagnetic coil by pulse width control by the pulse signal of the combustion level L ₁ from the burner arithmetic control device 61. Spray from the outlet.

The oil droplets sprayed from the fuel nozzle 31 become mixed gas by the wind supplied from the burner fan 50 into the vaporization cylinder 35, and this mixed gas is ignited by the spark discharge of the ignition electrode 40. After a while after ignition, the red flame combustion is switched to the blue flame combustion (confirmed by the combustion state detecting rod 48), and the so-called combustion control during ignition shifts to the control of the hot air temperature during combustion.

That is, in the central processing unit 60, the ongoing drying rate is calculated (for example, every hour) from the moisture data measured by the moisture meter 62 at regular intervals (for example, every 4 minutes), and preset based on the moisture value. The target temperature is set so that the current drying speed is made to follow the reference drying speed while being compared with the registered standard drying speed (see the section of "Prior Art"). Then, in the central processing control device 60, the difference between the target temperature and the detected value of the temperature sensor 63 is calculated, for example, every 12 seconds, and when the difference is larger than ± 0.5 ° C, the combustion level roughly equal to the difference is calculated. The burner arithmetic control unit 61 is instructed to change L ₂ . The burner arithmetic control unit 61 receives the combustion level L ₂ from the central arithmetic control unit 60, and based on this level signal, the ON time to the electromagnetic coil of the combustion nozzle 31 and the rotation speed of the burner fan 50 are set on the optimum combustion line. Control proportionally.

In this way, the whole paddy rice in the grain dryer 1 follows the so-called target drying rate curve in accordance with the standard drying speed, and the whole paddy rice is dried. Considering one paddy grain, as shown in FIG. Then, it is dried by being exposed to hot air for about 10 minutes passing through the drying section 2, and then tempered in the tempering tank 3. And the paddy rice that finished the 4th cycle is 1
The value reaches 6.5%, which is below the point (17.0%) at which the finish drying speed in the present embodiment is shifted, and the central processing unit 60 which receives this data from the moisture meter 62 controls the finish drying speed thereafter. Arithmetic control device for burner 61
Instruct. That is, the expected finish moisture value (14.5%) when dried at the standard drying rate as it is, when the expected finish moisture value is lower than the target finish moisture value (15.0%), it is smaller than the reference drying rate, In addition, a new drying speed for finishing that stops according to the target finishing moisture value is set, and subsequent drying control is performed based on this finishing drying speed. For example, the drying rate of the fifth cycle is 0.9%,
A drying rate of 0.45% per hour was calculated from the time required for one circulation (2 hours), and the drying loss rate in the sixth circulation was 0.6.
Calculate a drying rate of 0.3% per hour so that
Based on this, the target temperature is set and the combustion level of the burner 28 is changed. As a result, the particles are circulated twice to be dried by 1.5%, stopped at 15.0% of the target finish moisture value, and the other rice grains also have a finish moisture value of 15.0% (see the broken line in FIG. 4).

Next, in the case of paddy with an initial moisture content of 26%, the checkpoint was 17.0% in the 4th cycle, and when the expected moisture value at the time of finishing was calculated at this point, it was 15.0% as the target finish moisture value.
Therefore, in such a case, the drying control based on the finishing drying speed is not performed. The paddy rice finished according to the target finish moisture value is discharged to the outside of the machine through the bucket elevator 7 and the discharge chute 10 by pressing the "discharge button" switch.

In the above example, the finish drying rate was controlled by the hot air temperature, but the air volume was reduced and the drying rate was decreased by changing the rotation speed of the fan provided on the surface of the drying section facing the burner. In some cases, the rotation speed of the rotary valve under the drying unit may be increased.

[Brief description of drawings]

FIG. 1 is a perspective view of a grain dryer, FIG. 2 is a vertical cross-sectional view of a side center of FIG. 1, FIG. 3 is a conceptual diagram of control, and FIG. 4 is a graph for explaining the drying rate. 1 ... Grain dryer, 2 ... Drying unit, 3 ... Tempering tank, 4 ... Grain collecting gutter, 5 ... Lower screw conveyor, 6 ... Upper screw conveyor, 7 ... Bucket elevator, 8 ... Tension Included hopper, 9 ... Splasher, 10
…… Discharge chute, 14 …… Drying chamber, 15 …… Hot air chamber, 16…
… Exhaust chamber, 17 …… Rotary valve, 18A-18D …… Grain flow path, 19 …… Air inlet, 20 …… Air outlet, 21 …… Air supply box,
23, 24 ...... Aperture, 25 ...... Burner box, 28 ...... Burner, 29 ...... Oil pipe, 30 ...... Electromagnetic pump, 31 ...... Fuel nozzle, 32 ...... Blower pot, 33 ...... Combustion cylinder, 35 ...... Vaporization cylinder, 40 ...... Ignition electrode, 41 ...... Ignition transformer, 42 ...... Gas accelerating tube, 44 ...... Gasification tray, 48 ...... Combustion state detection rod, 50 ...... Burner fan, 52 ...... Burner fan Motor, 53 ……
Octopus generator, 55 ... Control box, 56
...... Product type switch, 57 …… Overhang amount switch, 58 …… Moisture setting switch, 59 …… Digital panel meter, 60…
… Central arithmetic control unit, 61 …… Burner arithmetic control unit,
62 ... Moisture meter, 67 ... Temperature sensor, 64 ... Sample flow path.

Claims (1)

[Claims] 1. A drying speed in progress is calculated based on moisture data from a moisture meter while the dried grain is circulated in a drying section and a tempering tank, and the drying rate and the moisture value of the dried grain are calculated in advance. In a grain drying method that controls the hot air temperature so that the drying speed follows the reference drying speed by comparing it with the reference drying speed that is set based on When the following is detected, the predicted moisture value when one cycle of the grain is circulated is calculated based on the drying speed at this time, and when this predicted moisture value is lower than the target finish moisture value, finish drying that is lower than the reference drying rate is performed. A method for drying grains, which comprises drying at a speed.