JP2816233B2 - Grain drying method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a grain drying method for supplying hot air to grains for drying.

[Conventional technology]

A cereal drying device for drying cereals supplies hot air to the cereals to dry the cereals. In addition, the grain drying apparatus controls the temperature of hot air by the following drying method.

That is, a plurality of grains during drying are sampled at predetermined time intervals, and the moisture content of the grain sampled by the moisture sensor is measured. Next, the average value of the measured values of the moisture content is determined, and the average value of the moisture content determined last time is calculated to calculate the drying speed of the grain. The temperature of the hot air is controlled such that the drying speed becomes a preset drying speed (drying rate).

[Problems to be solved by the invention]

However, the moisture content of the grain during drying is not uniform but varies from grain to grain. Since the drying method controls the temperature of the hot air based on the average value of the water content, the temperature of the hot air may not be appropriate for the water content of the grain. For example, even if the average value of the moisture content of the grain during drying is the same,
When the distribution of moisture content for each grain spreads to higher values, spreads to lower values, and spreads uniformly to higher and lower values (in this case, There is a case where the distribution width is wide and a case where the distribution width is narrow). In the conventional grain drying method, the average value is the same in any of the above cases, so that the temperature of the hot air is controlled to be the same. However, kernels are susceptible to thermal injury when dried at high temperatures with high moisture content. When the distribution of the moisture content of the grain is spread to a higher one, the ratio of the grain having a high moisture content is high,
In addition, when the distribution is uniform but the distribution width is large, there are grains having a high moisture content, so that a large number of grains may be damaged by heat, resulting in the occurrence of cracks and the like.

The present invention has been made in view of the above facts, and has as its object to obtain a grain drying method that can be dried at an appropriate hot air temperature according to the distribution of the water content.

[Means for solving the problem]

In order to achieve the above object, a grain drying method according to the invention according to claim 1 is a grain drying method in which hot air is supplied to a grain to dry the grain, wherein the moisture content of the grain is measured a plurality of times, and the moisture content is measured. Determine the distortion of the value distribution, if the distribution of the measured moisture content is distorted to the higher moisture content side, lower the temperature of the hot air, the distribution of the measured moisture content is the lower moisture content side When the temperature is distorted, the temperature of the hot air is increased.

Further, in the invention according to claim 2, in the invention according to claim 1, when the distribution of the measured value of the water content is a normal distribution or a distribution close to the normal distribution and the distribution width is wide, the temperature of the hot air is decreased. When the distribution of the measured value of the water content is a normal distribution or a distribution close to the normal distribution and the distribution width is narrow, the temperature of the hot air is increased.

[Action]

According to the first aspect of the present invention, the distortion of the distribution of the measured value of the moisture content of the grain is determined, and when the distribution of the measured value of the moisture content is distorted toward the higher moisture content side, that is, the grain of the grain having the higher moisture content is determined. When the ratio is high, the temperature of the hot air is decreased, so that a large number of grains are not damaged by heat and a crack is not generated. In addition, when the distribution of the measured value of the moisture content is distorted toward the higher moisture content side, that is, when the proportion of the grains having a high moisture content is low, the temperature of the hot air is increased, so that the drying can be performed quickly. it can.

The distortion of the distribution of the measured values can be determined based on, for example, the degree of asymmetry. The asymmetry is a value indicating the distortion of the distribution. For example, the relative asymmetry which is one of the asymmetries is a difference between the average value of the measured values and the average number (the point at which the frequency of the measured values is the maximum). Calculate by dividing by standard deviation. When the sign of the value of the degree of asymmetry is positive and the absolute value is large, the distribution of the moisture content is a positive asymmetric distribution, and the distribution of the moisture content spreads toward higher values (see FIG. 1 (D)). . In this case, the temperature of the hot air is lowered because the proportion of grains having a high moisture content is high. When the sign of the value of the degree of asymmetry is negative and the absolute value is small, the distribution of the water content is a negative asymmetric distribution, and the distribution of the water content spreads to lower values (see FIG. 1 (C)). ). In this case, the temperature of the hot air is increased because the proportion of grains having a high water content is low. Thereby, the grain can be dried at an appropriate hot air temperature according to the distortion of the distribution of the water content.

According to the second aspect of the present invention, the distribution of the measured value of the moisture content of the grain is a normal distribution or a distribution close to the normal distribution and there is no distortion in the distribution, but when the distribution width is wide, that is, a grain having a high moisture content is included. In such a case, the temperature of the hot air is lowered, so that a large number of grains are not damaged by heat and a crack is not generated. Further, when the distribution of the measured value of the water content of the grain is a normal distribution or a distribution close to the normal distribution and the distribution width is narrow, the temperature of the hot air is increased, so that the drying can be performed quickly.

When the absolute value of the value of the degree of asymmetry is small, the distribution of the water content is a substantially symmetric distribution, and is a normal distribution or a distribution close to a normal distribution. When the distribution width is substantially symmetric and the distribution width is large (when the degree of dispersion is large), for example, when the standard deviation value is large (see FIG. 1 (B)), the dispersion of the measured value of the water content is large and the standard deviation value is small. Compared to (see FIG. 1 (A)), the proportion of grains having a high moisture content is high. For this reason, when the distribution width of the measured values is wide, for example, when the standard deviation value is large, the temperature of the hot air is lowered. When the distribution width of the measured values is narrow, for example, when the standard deviation value is small, the temperature of the hot air is decreased. To raise. Thereby, the grain can be dried at an appropriate hot air temperature according to the distribution width of the water content.

In the present invention, the determination of the distribution state of the measured value of the moisture content is not limited to the above method, for example, the frequency of the measured value having a higher moisture content than the average value of the measured values, the average value of the moisture content The frequency can be determined by comparing the frequency of the measured value with a lower moisture content than that of the measured value, or can be determined by calculating the difference between the frequency and a standard distribution (for example, a normal distribution).

〔Example〕

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

FIGS. 2 and 3 show a grain drying apparatus 10 to which the grain drying method of the present invention can be applied. The body 12 of the grain drying device 10 has a box shape that is high vertically and long in front and back. Airframe
The upper inner cavity of 12 is a grain tank 14 and the lower inner cavity is a drying section 16.

The drying section 16 is formed with a flow-down passage 18 partitioned by a porous net-like partition so that grains in the grain tank 14 flow down. Between the downstream flow paths 18, air guide paths 20 and exhaust air paths 22 are formed alternately. A burner 24 is connected to the air guide path 20, and a suction blower 27 is connected to the exhaust path 22. For this reason, the hot air generated by the burner 24 is sent to the air guide path 20,
The air flows through 18 to an exhaust passage 22. Therefore, the grains in the downflow path 18 are dried by the hot air. A temperature sensor 58 is provided near the burner 24. Temperature sensor 58
Detects the temperature of the hot air sent from the burner 24.

A shutter drum 30 that reciprocates and rotates by a motor 28 is disposed at an opening at the lower end of the downflow path 18. Grains that pass through the downflow path 18 and are dried are collected by a grain collecting section below the shutter drum 30.
It is fed out to 31. At the side of the grain collecting section 31, an insertion port 29 for inserting grain into the machine is provided.

A lower screw conveyor 34 driven by a synchronous motor 32 is disposed below the grain collecting unit 31 so as to convey the grain fed by the shutter drum 30 to the front side of the machine body 12. A bucket conveyor 36 stands upright on the front side of the body 12.

The inside of the bucket conveyor 36 includes an endless conveyor 39 driven by a synchronous motor 38 and a grain transport bucket 41 attached to the endless conveyor 39. The bucket conveyor 36 conveys the grains sent from the lower screw conveyor 34 to the uppermost part of the body 12. One end of an upper screw conveyor 40 corresponds to the upper end of the bucket conveyor 36, and a rotary type equalizer 42 is connected to the other end of the upper screw conveyor 40.

In addition, the screw conveyor 40 and the rotary equalizer 42 are
Driven by a motor 38 together with a bucket conveyor 36,
The grains lifted and conveyed by the bucket conveyor 36 are distributed and distributed to the grain tank 14 of the body 12.

At the lower part of the bucket conveyor 36, a moisture sensor 44 for detecting the moisture value of the grain is arranged, and a part of the grain scooped up when the bucket 41 for transporting the grain of the bucket conveyor 36 is turned over. It is designed to flow into.

As shown in FIG. 4, a power switch 50, a drying operation switch 52, and a moisture setting dial 5 provided on the operation unit 60 are provided.
3. The grain setting dial 54 and the humidity setting dial 56 are each connected to a control circuit 48 arranged inside the body 12. The control circuit 48 includes the burner described above.
24, a suction blower 27, a motor 28, a motor 32, a motor 38, a moisture sensor 44, and a temperature sensor 58 are connected, and an AC power supply 51 is connected via a power switch 50, and a predetermined voltage (100 V Or 200 V) and an alternating current of a predetermined frequency (50 Hz or 60 Hz) is supplied.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. The flow chart shown in FIG.
This is executed when the power switch 50 is turned on, the grain is put in the grain drying apparatus 10, and the drying operation switch 52 is turned on.

In step 100, the initial values of the set water content and the temperature of the hot air stored in the control circuit 48 in advance are read. The grain drying apparatus 10 performs a drying process until the moisture content of the grain reaches the set moisture content. The set moisture content is determined and stored for each grain type, and the set moisture content according to the grain type set by the grain setting dial 54 is read.

In step 102, the burner 24 is ignited, the suction / exhaust air blower 27 is turned on, and the motors 28, 32, and 38 are turned on, and the shutter drum 30 and the transporting unit (the lower screw conveyor 34, the bucket conveyor 36, the upper screw conveyor 40) are turned on. Then, the rotary equator 42) is rotated.

As a result, the hot air is sucked into the suction exhaust fan 27 and
The hot air sent to the air duct 20 and sent to the air duct 20 flows down
It is supplied directly to the grain within 18. At this time, the temperature of the hot air is controlled to be the initial value. Further, the hot air after sucking the moisture of the grain is discharged to the outside of the grain drying device 10 through the exhaust air passage 22. Further, the grain is fed out from the drying section 16 to the grain collecting section 31 by the shutter drum 30, and is successively conveyed from the grain collecting section 31 to the bucket conveyor 36 side by the lower screw conveyor 34, and further rotated by the bucket 41 of the bucket conveyor 36. Is transported upward. Bucket conveyor 36
The grain conveyed above the body 12 by the upper screw conveyor 40 is sent to the upper central part of the body 12 and returned to the grain tank 14 in the body by the rotary equalizer 42.

In step 104, a predetermined amount of grains is supplied to the moisture sensor 44, the moisture sensor 44 measures the moisture content of each grain, and calculates an average value of the moisture content. In step 106, step 104
Then, it is determined whether or not a predetermined time has elapsed since the measurement of the moisture content. If the predetermined time has not elapsed, go to step 10.
Repeat 6. After the elapse of the predetermined time, the process proceeds to step 108. In step 108, a predetermined amount of grains is again applied to the moisture sensor 44.
And the moisture sensor 44 measures the moisture content of each grain. In the next step 110, the average value of the water content is calculated.

In step 112, it is determined whether or not the average value of the water content calculated in step 110 has become equal to or less than the set water content, that is, whether or not the grain drying process has been completed. If the average value of the moisture content is not equal to or less than the set moisture content, the average value of the moisture content determined this time and the average value of the moisture content determined last time are compared in step 114 to indicate the degree of drying from the previous time. Ask for.
In step 116, the hot air temperature t is determined so that the drying loss rate becomes a predetermined drying loss rate. The hot air temperature t can be obtained by referring to a table or the like stored in advance.

Hereinafter, in steps 118 to 128, a process of correcting the temperature of the burner 24 according to the variation in the dry state of the grain is performed. That is, in step 118, the standard deviation value S and the degree of asymmetry Sk are obtained. The standard deviation value S and the degree of asymmetry Sk represent the number of samples of the kernel as n, and the measured value of the moisture content of each kernel.
X ₁ , X ₂ , X ₃ ,..., The average value of the water content, and the average number of measured values is M ₀ , This formula is a calculation formula of the relative asymmetry, and the asymmetry of each distribution having different standard deviation values can be compared. By calculating the above equation, the standard deviation value S and the degree of asymmetry can be calculated.
Sk can be obtained. In step 120, the degree of asymmetry Sk
And “0” are compared. When the degree of asymmetry is a value larger than “0”, the distribution of the water content is a positive asymmetric distribution, and the distribution of the water content spreads toward higher values as shown in FIG. 1 (C). In such a case, when the temperature of the hot air is increased, a large number of grains are damaged by heat. For this reason, step 122
Then, a predetermined value α is subtracted from the hot air temperature t set in step 116. As a result, the temperature of the hot air is lowered, and heat damage to grains having a high moisture content is prevented. After execution of step 122, the process proceeds to step 130.

When the degree of asymmetry is a value smaller than “0”, the distribution of the water content is a negative asymmetric distribution, and the distribution of the water content spreads toward higher values as shown in FIG. 1 (D). For this reason, in step 124, the hot air temperature t set in step 116 is set.
Is added to the predetermined value α. As a result, the temperature of the hot air is raised to quickly dry the grains. After the execution of step 124, the process proceeds to step 130.

When the value of the degree of asymmetry is “0”, the distribution of the water content is a symmetric distribution, and the reference value S ₀ of the standard deviation value stored in advance is read in step 126. Step the standard deviation value S obtained in 128 in step 118 is compared with the reference value S ₀ of the standard deviation.

When the standard deviation value S is larger than the reference value S _0, the measured value of the moisture content varies greatly, and the proportion of the grains having a high moisture content is higher than when the standard deviation value is small. Therefore, the process proceeds to step 122, where the hot air temperature t is decreased. For this reason, grains with a high moisture content do not suffer from thermal injury. Is relatively small variations in the measurement of water content when the standard deviation S is smaller than the reference value S _0, the moisture content of each grain is on average. Therefore, the process proceeds to step 124, where the hot air temperature t
To rise. Further, when the standard deviation value S is equal to the reference value S _0, the routine proceeds to step 130.

In step 130, the burner 24 is controlled based on the detection value of the temperature sensor 58 so that the temperature of the hot air supplied to the grain becomes the hot air temperature t obtained in the above steps. Step
After the execution of step 130, the process returns to step 106, and steps 106 to 130 are repeated until the determination of step 112 is affirmed and the drying process is completed.

If the determination in step 122 is affirmative, the process proceeds to step 132, in which the burner 24 is extinguished, the suction and exhaust fan 27 is turned off, and the motors 28, 32, and 38 are turned off, and the shutter drum 30 and the transport unit (lower screen) are turned off. Yukon conveyor 34, bucket conveyor
36, Stop the upper screw conveyor 40 and the rotary equalizer 42) to end the drying operation.

As described above, in this embodiment, the water content of a plurality of grains is measured at predetermined time intervals, and the asymmetry Sk of the distribution of the measured value of the water content is measured.
When the value of the degree of asymmetry is positive, the predetermined value α is subtracted from the hot air temperature t, and when the value is negative, the predetermined value α is added to the hot air temperature t. Can be dried at an appropriate hot air temperature.

When the value of the degree of asymmetry Sk is “0”, the standard average value S of the distribution of measured values is compared with the reference value S _0, and the standard deviation S of the distribution of measured values is smaller than the reference value S _0. When it is large, the temperature of the hot air is lowered, and the standard deviation S of the distribution of measured values is the standard value.
When the temperature is smaller than S ₀ , the temperature of the hot air is increased, so that the grains having a high moisture content do not suffer from thermal injury when the dispersion of the measured values is large.

In the present embodiment, the predetermined value α is a constant, but the present invention is not limited to this, and the predetermined value α may be changed according to the absolute value of the degree of asymmetry Sk. Good.

In the above description, an example using the asymmetry and the standard deviation has been described.However, it is assumed that the body content can be reduced by using only the asymmetry, and that the distribution of the water content is a normal distribution or a distribution close to a normal distribution. If possible, control may be performed using only the standard deviation.

〔The invention's effect〕

As described above, the invention according to claim 1 determines the distortion of the distribution of the measured value of the moisture content of the grain, and when the distribution of the measured value of the moisture content is distorted toward the higher moisture content side, the hot wind If the temperature is lowered and the distribution of the measured moisture content is distorted toward the lower side of the moisture content, the temperature of the hot air is increased, so depending on how the distribution of the measured moisture content is distorted. ,
It has an excellent effect that cereals can be dried at an appropriate hot air temperature.

In the invention according to claim 2, in the invention according to claim 1, when the distribution of measured values of the water content of the grain is a normal distribution or a distribution close to the normal distribution and the distribution width is wide, the temperature of the hot air is decreased, and When the distribution of the measured value of the water content is a normal distribution or a distribution close to the normal distribution and the distribution width is narrow, the temperature of the hot air is increased.In addition to the above effects, the distribution of the measured value of the water content is changed to a normal distribution or a normal distribution. When the distribution is close, the grain can be dried at an appropriate hot air temperature according to the width of the distribution.

[Brief description of the drawings]

1 (A) to 1 (D) are diagrams illustrating the operation of the present invention, FIG. 2 is a schematic sectional view of the grain drying apparatus of the present embodiment, and FIG. 3 is along the line III-III in FIG. FIG. 4 is a block diagram of a circuit of a control device of the grain drying apparatus of the present embodiment, and FIG. 5 is a flowchart for explaining the operation of the present embodiment. 10 ... grain drying device, 24 ... burner, 48 ... control circuit, 58 ... temperature sensor.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F26B 25/00 F26B 17/14

Claims (2)

(57) [Claims] 1. A grain drying method comprising supplying hot air to a grain and drying the grain, wherein the moisture content of the grain is measured a plurality of times, the distortion of the distribution of the measured moisture content is determined, and the measured moisture content is measured. When the distribution is distorted toward the higher moisture content side, the temperature of the hot air is decreased, and when the distribution of the measured moisture content is distorted toward the lower moisture content, the temperature of the hot air is increased. A grain drying method comprising: 2. When the distribution of the measured value of the water content is a normal distribution or a distribution close to the normal distribution and the distribution width is wide, the temperature of the hot air is lowered, and the distribution of the measured value of the water content is a normal distribution or The grain drying method according to claim 1, wherein the temperature of the hot air is increased when the distribution is close to a normal distribution and the distribution width is narrow.