JP2010271021A - Exhaust air circulating type grain drier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grain drier capable of efficiently promoting moisture equalization by keeping predetermined grain temperature while suppressing sweating of grain, in a case that the grain drier is stopped and kept in a predetermined high-temperature state by a resting process in grain dry processing by exhaust air circulation. <P>SOLUTION: The exhaust air circulating type grain drier includes a control part (F) which carries out exhaust air circulation drying control for making exhaust air diverge to the circulation side by switching valves (22, 23) and circulating the air in a grain drying part (3) to dry the grain by an exhaust air circulation ratio according to a detected moisture value of the grain, and drying resting control for stopping the grain drying if the detected moisture value reaches a separately-set resting reference moisture value. The control part (F) gradually opens the switching valves (22, 23) until all the air is exhausted in a predetermined moisture value range until the detected moisture value in the exhaust air circulation drying control reaches the resting reference moisture value, gradually decreases the exhaust air circulation ratio at predetermined speed, and then, carries out the drying resting control. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust air circulation type grain dryer that performs exhaust air circulation drying of grains and the like by returning exhaust air diverted from an exhaust air duct to a grain drying section by a reflux duct.

As in the example of Patent Document 1, a part of the exhaust air is diverted from the exhaust duct that exhausts the exhaust air of the grain drying section, and is returned to the grain drying section by the reflux duct, thereby being mixed and supplied together with hot air from the hot air supply section. An exhaust air circulation type grain dryer that performs exhaust air circulation drying is known.
This exhaust air circulation type grain dryer ensures the quality of the grain at a predetermined grain drying speed while circulating a constant rate of exhaust air according to the moisture content of the grain measured by the moisture meter, while suppressing heating loss associated with hot air discharge. In addition, the grain drying operation can be performed efficiently.

  In addition, when there is unevenness in drying, by providing a pause process in which the grain dryer is stopped and kept at a certain high temperature, moisture transfer between grains can be promoted and the moisture value can be made uniform.

JP 2008-224199 A

  However, during high-speed drying by exhaust air circulation, the grain surface is in a high temperature and high humidity state. There was a problem that the temperature was lowered, effective moisture transfer was suppressed, and drying unevenness was not solved.

  An object of the present invention is to maintain a predetermined grain temperature while suppressing the steaming of grains when the grain dryer is stopped and held at a certain high temperature by a pause process in the grain drying process by exhaust air circulation. An object of the present invention is to provide a grain dryer that can efficiently promote uniform moisture.

  The invention according to claim 1 divides the exhaust air discharged from the grain drying section (3) for drying the grains with hot air to the circulation side by the switching valve (22, 23), and the diverted exhaust air is separated into the grain drying section ( 3) Exhaust air circulation drying control that circulates and drys the grain, and drying pause control that stops grain drying when the grain moisture value detected in the exhaust wind circulation drying control reaches a separately set pause reference moisture value. In the exhaust air circulation type grain dryer provided with the control part (F) to perform, the said control part (F) is about the predetermined | prescribed moisture value range until the detected water value in exhaust air circulation drying control reaches a rest reference | standard water value. The switching valve (22, 23) is gradually opened to full discharge, and the exhaust air circulation rate is gradually decreased at a predetermined speed, and then drying stop control is performed.

  In the exhaust air circulation type grain dryer, when the grain moisture value to be detected reaches a predetermined moisture value in the vicinity of the pause reference moisture value, the exhaust wind circulation rate gradually decreases at a predetermined speed by the control unit, and becomes the pause reference moisture value. When reaching, the exhausting operation of the exhaust air is performed and the grain drying operation is stopped.

  The invention according to claim 2 divides the exhaust air discharged from the grain drying section (3) for drying the grains with hot air to the circulation side by the switching valve (22, 23), and the diverted exhaust air is separated into the grain drying section ( 3) A control unit that performs exhaust air circulation drying control that circulates to dry the grain and drying suspension control that stops grain drying when an elapsed time in the exhaust air circulation drying control reaches a separately set suspension reference time. F) In the exhaust-air circulation type grain dryer provided with F), the said control part (F) is a switching valve (22, 23) about the predetermined time range until the elapsed time in exhaust-air circulation drying control reaches | attains reference | standard time of a stop. Is gradually opened until full discharge, and the exhaust air circulation rate is gradually reduced at a predetermined speed, and then drying suspension control is performed.

  When the elapsed time reaches a predetermined time in the vicinity of the pause reference moisture value, the exhaust wind circulation type grain dryer gradually reduces the exhaust wind circulation rate at a predetermined speed, and when the elapsed time reaches the pause reference time, The whole grain is discharged and the grain drying operation is stopped.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the control unit performs a discharge full-closed control of the switching valve during the drying pause control.
In the exhaust air circulation type grain dryer, the outside air is shut off by the switching valve for fully discharging.

  In the exhaust air circulation type grain dryer according to the first aspect of the invention, the control unit performs the exhaust air circulation drying operation at the exhaust air circulation rate according to the detected moisture value, and the detected moisture value is close to the pause reference moisture value. When the specified moisture value is reached, the exhaust air circulation rate gradually decreases at a predetermined speed, and when reaching the pause reference moisture value, the exhaust air is exhausted and the grain drying operation is stopped. The machine can keep the grain temperature high while suppressing the steaming due to the recirculation of the exhaust air when the grain drying is stopped at the resting standard moisture value. As a result, the moisture transfer is promoted and the moisture spots are made uniform. be able to.

  The exhaust air circulation type grain dryer of the invention according to claim 2 performs the exhaust air circulation drying operation at the exhaust air circulation rate according to the detected moisture value by the control unit, and the elapsed time is in the vicinity of the pause reference moisture value. When the predetermined time is reached, the exhaust air circulation rate gradually decreases at a predetermined speed, and when the reference time is reached, the exhaust air circulation rate is exhausted and the grain drying operation is stopped. When the grain drying is stopped at the stop reference time, the grain temperature can be kept high while suppressing the sultry due to the return of the exhaust air, and as a result, the moisture transfer can be promoted and the moisture spots can be made uniform. .

  In addition to the effect of claim 1 or claim 2, the exhaust air circulation type grain dryer of the invention according to claim 3 makes it easy to maintain the grain temperature during the drying pause due to the outside air shut-off action by the switching valve for fully closing the discharge. In addition, moisture fluctuation due to outside air can be suppressed.

Perspective perspective view for explaining the internal configuration of the grain drying section of the grain dryer Front view explaining the internal configuration of the grain drying section of the grain dryer Rear perspective view of the main part of the wind exhaust section Longitudinal section of the main part of the wind exhaust section Action plan view showing ventilation streamlines in grain drying section System configuration diagram of dryer operation control Flow chart 1 of operation control of dryer Flow chart 2 of operation control of dryer Characteristic diagram of start time Coefficient characteristic diagram (a) and start time characteristic diagram (b)

Embodiments specifically configured based on the above technical idea will be described below with reference to the drawings.
1 and 2 are a perspective view and a front view, respectively, for explaining the internal configuration of the grain drying unit of the grain dryer.
The grain dryer includes a grain drying unit 3 that receives grains from a storage unit (not shown) that stores the grains at the upper part of the machine body and feeds them from the lower end at a constant speed, and the grains dried by the grain drying unit 3 And a cereal collection unit 4 for transferring the collected product to the storage unit again. And the grain stuck in the storage part is a so-called grain circulation type structure in which the appearance is box-shaped with a structure that is dried in the grain drying part 3 and supplied to the storage part again from the grain collecting part 4 and tempered. . In the present embodiment, the burner 5 side, which will be described later, is called the front side (front surface), and the exhaust fan 6 side is called the rear side (back surface).

  As for the grain drying unit 3, left and right grain flow passages 13 and 13 are installed between the front plate 3a and the back plate 3b of the fuselage, and the left and right outer sides are sandwiched between the grain flow passages 13 and 13, respectively. Hot air chambers 8 and 8 and a central air exhaust chamber 12 are formed. The left and right grain flow down passages 13 and 13 are grain passages having a net material structure through which hot air can permeate. It faces the grain part 4. In addition, the wind exhaust chamber 12 surrounded by the left and right grain flow down passages 13 and 13 is formed in both flows by left and right inclined guide portions 13a and 13a having a mountain shape at the top. The left and right inclined guide portions 13a and 13a are supported by left and right frames 13b and 13b installed between the front plate 3a and the back plate 3b.

  A hot air supply unit S that includes a burner 5 that heats the outside air and supplies hot air to the hot air chamber 8 is disposed at the front surface of the grain drying unit 3, and exhaust air that sucks and exhausts the exhaust air from the exhaust air chamber 12 at the rear surface. An exhaust air discharge unit T including the wind fan 6 is disposed.

  As shown in FIGS. 3 and 4, the exhaust air discharge portion T is provided with a discharge air duct 20 projecting from the back plate 3 b to the outside of the box as shown in FIGS. 3 and 4. A circulation duct 21 is connected to the upper part of the air duct, and an introduction tube 6a is extended from the back plate 3b toward the inside of the box body in the exhaust air chamber 12 through the exhaust air duct 20 and forwardly. By attaching the rotary blade 6b, the exhaust fan 6 is configured such that its tip projects into the exhaust chamber 12. Further, a fan motor 61 is disposed on the upper portion of the introduction cylinder 6a, and a transmission belt 62 is provided on the back side to drive the rotary blade 6b.

  Since this transmission belt 62 drives the rotor blade 6b by an external fan motor 61, it is inevitable that the exhaust belt leaks from the opening through which the transmission belt 62 penetrates the fan body of the exhaust fan 6. Since the fan motor 61 is installed in the exhaust chamber 12 integrally with the exhaust fan 6, a simple fan drive unit by the external fan motor 61 is configured without causing exhaust air leakage to the outside air. Can do.

  A first control valve 23 is provided in the exhaust duct 20 to allow the circulation duct 21 to communicate upward, and a second control valve 22 is provided in the circulation duct 21 to switch exhaust air so that both can be adjusted in conjunction. Constructed as a switching valve, the return exhaust air is supplied to the mixing duct A from the circulation duct 21 through the return ducts 27, 27 that vertically cut the hot air chambers 8, 8 from the front plate 3a. It is mixed with hot air and supplied to the hot air chambers 8 and 8 through the hot air chamber supply port P.

The first control valve 23 is adjusted by the first control valve adjustment motor 23m, and the second control valve 22 is adjusted by the second control valve adjustment motor 22m. The ratio of guiding the exhaust air discharged by the exhaust fan 6 to the outside of the box body and the ratio guiding it to the circulation duct 21 side are adjusted by the control valves 22 and 23.
For example, when exhausting all exhaust air to the outside of the box, the second control valve 22 is fully closed, and the first control valve 23 is fully open, and when returning all exhaust air to the inside of the box, the second control valve 22 is Fully open and the first control valve 23 fully closed.

  Further, the circulation duct 21 is configured to be detachable for mounting and maintenance of the exhaust fan 6, the fan motor 61, and the transmission belt 62. In this embodiment, although the member to be attached / detached is not shown, it can be attached / detached with a knob bolt or the like, and the circulation duct 21 and the second control valve 22 are integrally formed.

  The left and right frames 13b that form the openings W in the shape of the exhaust chamber 12 in the back plate 3b in the range covered by the circulation duct 21 and that support the left and right inclined guide portions 13a and 13a and reach the front plate 3a, The left and right guide rails 63 and 63 are provided from the back plate 3b along the line 13b. The left and right guide rails 63 and 63 support the exhaust fan 6 externally attached to the fan motor in such a manner that the motor base is suspended.

  As shown in FIG. 5, the grain dryer having the above-described structure projects an introduction cylinder 6 a into the exhaust chamber 12 of the grain drying unit 3, as shown in FIG. 5. By projecting the exhaust fan 6 with the fan body extending inside the exhaust chamber 12, the amount of the exhaust duct 20 projecting to the rear side can be suppressed. It is possible to shorten the overall length of the aircraft while ensuring it. Further, in the case where the circulation duct 21 is provided, it is only necessary to increase the minimum projecting dimension necessary for the configuration of the circulation duct 21 from the back plate 3b.

  Further, by the operation of the exhaust air fan 6 of the exhaust air exhaust unit T, hot air is supplied from the hot air supply unit S to the left and right hot air chambers 8 and 8, and this hot air passes through the left and right grain flow passages 13 and 13. , And the exhausted air is sucked and discharged from the exhaust chamber 12 by the exhaust fan 6, and part of the exhaust air is forwarded from the circulation duct 21 through the left and right return ducts 27, 27. Then, the mixture is mixed with hot air in the mixing duct A and supplied to the hot air chambers 8 and 8, thereby enabling high-speed drying.

  In this case, since the exhaust air that has passed through the grain flow passage 13 is sucked from the position protruding to the center of the exhaust chamber 12, the drying action of the grain flow passages 13, 13 is averaged. The grain dryer can reduce drying spots due to grain passing positions in the grain flow down passages 13 and 13, and can be uniformly dried.

The operation of FIG. 5 will be described.
The exhaust air is supplied from the circulation duct 21 to the hot air chamber on the front side of the box through the return ducts 27 and 27 and the mixing duct A, and the opening of the hot air chambers 8 and 8 around the rear ends of the return ducts 27 and 27. Some are supplied from the portion R to the rear side of the hot air chambers 8 and 8.

  Hot air is attracted to the front and rear center sides of the hot air chambers 8 and 8 by the action of the exhaust fan 6 from the burner 5 and the action of exhaust air supplied to the rear side of the hot air chambers 8 and 8. Therefore, the hot air is easily averaged and distributed throughout the box body, and the mixing with the exhaust air becomes good, and dry spots due to the grain passage positions in the grain flow passages 13 and 13 can be reduced. Uniform drying is possible.

Other technical features are summarized as follows.
1stly, while the wind exhaust chamber 12 forms the top part in the shape of a mountain by the left and right inclination guide parts 13a and 13a, it forms the grain flow passages 13 and 13 in each lower part, and these right and left grain flow passages 13 , 13 and the fan motor 61 for driving between the left and right inclined guide portions 13a, 13a at the upper portion thereof, and the space between the inclined guide portions 13a, 13a. Since the external fan motor 61 is accommodated, a drying device with a simple configuration can be configured in a compact manner by taking advantage of wasted space.

  Secondly, the fan motor 61 is arranged inside the back plate 3b, and is configured to be detachably provided with a circulation duct 21 that diverges from the discharge side of the exhaust duct 20, so that it can be returned to the hot air chambers 8 and 8. At the same time, an opening W of the air exhaust chamber 12 is formed in the back plate 3b within the range covered by the circulation duct 21, and the motor base of the fan motor 61 is supported by the left and right guide rails 63, 63, so that the fan motor is externally attached. The exhaust fan 6 can be easily assembled by sliding it from the opening of the back plate 3b, and it is possible to remove the circulation duct 21 from the opening W of the back plate 3b without requiring a special inspection lid. Maintenance of the fan motor 61 and the transmission belt 62 is possible.

(Drying control)
As shown in FIG. 6, the operation control of the dryer is performed by inputting signals from the temperature sensor TA, the humidity sensor HA, the moisture meter 10 and the like to the input side of the control unit F, according to these states. Thus, component devices such as the burner 5, the exhaust fan 6, and the first control valve 23 and the second control valve 22 that constitute the switching valve are connected to the output side so that the devices can be controlled.

  The specific drying control by the control unit F will be described with reference to the flowchart 1 of FIG. 7. During the drying operation, the first control valve 23 is set so that the exhaust air circulation rate is in accordance with the grain moisture value detected by the moisture meter 10. And exhaust air return control for adjusting and controlling the second control valve 22.

  In the drying method of high-speed drying by exhaust air circulation, in order to remove the layer unevenness of the cereal grain moisture, when setting the pause drying in the middle of drying, for setting to pause at a predetermined pause reference moisture value, When the condition is satisfied by the control processing step S1 (hereinafter abbreviated as “S1”) for determining that the drying has progressed to the vicinity (for example, + 0.5%) of the rest reference moisture value, The first control valve 23 and the second control valve 22 are adjusted and controlled for each set angle so that the exhaust air circulation rate is gradually decreased (S2a, S2b) every time, so that there is no circulation or a small amount of circulation. After the amount is reached, the dryer is paused when the pause moisture value is reached (S3a to S3c). Include burner post-purge time.

  In the case of setting to pause at a predetermined elapsed time, as shown in the flowchart 2 of FIG. 8, the pause reference time (S12b) is used instead of the pause reference moisture value, and when that time approaches (for example, from 30 minutes before ) The first control valve 23 and the second control valve 22 are adjusted and controlled for each set angle so as to gradually reduce the exhaust air circulation rate (S11).

(Pause process)
Dryer pause control is performed after the temperature of the exhaust air is monitored and the grain temperature is lowered to a level at which no body split occurs. Further, at the time of a pause during the operation of the pause drying mode, the switching valve is fully closed to prevent air from entering and leaving (S3c). By closing the switching valve when the operation is stopped by this fully closed control, it is possible to prevent air from entering and exiting and to be less susceptible to the influence of outside air, to prevent excessive drying and to promote uniform grain condition in the machine. it can.

  In this way, the exhaust air circulation type grain dryer performs the exhaust air circulation drying operation at the exhaust air circulation rate corresponding to the detected moisture value by the control unit, and the detected moisture value is a predetermined value near the pause reference moisture value. When the moisture value is reached, the exhaust air circulation rate is gradually reduced at a predetermined speed, and when the suspension reference moisture value is reached, the exhaust air is completely discharged and the grain drying operation is stopped.

  Therefore, the above-described exhaust circulation type grain dryer can keep the grain temperature high while suppressing the steaming due to the return of the exhaust air when the grain drying is stopped at the suspension reference moisture value, thereby promoting the moisture transfer. Thus, the water spots can be made uniform.

(Stop process)
In the case of high-speed drying, the dryer is controlled so that drying is fast, so the end of the operation is often at night and during the prolonged operation until dry grain is taken out, air enters and exits during rest operation due to outside air conditions. If this happens, only the ventilation section may dry or the moisture may return.Therefore, a mode is provided to close the discharge side of the exhaust duct to prevent the outside air from entering and exiting. When the operation is finished, the switching valve is controlled to be fully closed (S5a to S5c).

(Circulation process)
Next, with regard to the start timing of the exhaust air circulation, the combustion deteriorates when there is a lot of dust even after a lapse of a predetermined time from the start of operation, and the time is wasted when waiting for the whole crop from the start of operation. Therefore, as shown in the characteristic diagram of the start time in FIG. 9, by determining the exhaust air circulation start time according to the initial moisture value, it is possible to ensure burner combustion while suppressing dead time. it can.

  Moreover, after calculating the round time of the grain based on the amount of grain, as shown in the coefficient characteristic diagram of FIG. 10 (a), the exhaust air circulation start timing based on the initial moisture value is coefficientized, and the coefficient Is accumulated in the cycle time of the grain, as shown in the characteristic diagram of the start time in FIG. 10B, the exhaust air circulation start time corresponding to the amount of tension can be obtained.

3 Grain drying section 5 Burner 6 Exhaust fan 10 Moisture meter 14 Fixed feed valve 20 Exhaust duct 21 Circulation duct 22 Second control valve (switching valve)
23 First control valve (switching valve)
27 Reflux duct F Control part

Claims (3)

The exhaust air discharged from the grain drying section (3) for drying the grains by hot air is diverted to the circulation side by the switching valves (22, 23), and the diverted exhaust air is circulated to the grain drying section (3) to dry the grains. And a control unit (F) for performing the exhaust air circulation drying control and the dry suspension control for stopping the grain drying when the grain moisture value detected in the exhaust air circulation drying control reaches a separately set suspension reference moisture value. In the exhaust circulation type grain dryer,
The control unit (F) gradually opens the switching valve (22, 23) until the exhaust is exhausted for a predetermined moisture value range until the detected moisture value in the exhaust air circulation drying control reaches the pause reference moisture value. An exhaust air circulation type grain dryer characterized by performing drying suspension control after gradually decreasing the circulation rate at a predetermined speed. The exhaust air discharged from the grain drying section (3) for drying the grains by hot air is diverted to the circulation side by the switching valves (22, 23), and the diverted exhaust air is circulated to the grain drying section (3) to dry the grains. Exhaust air circulation drying control provided with a control unit (F) for performing the exhaust air circulation drying control, and when the elapsed time in the exhaust air circulation drying control reaches a separately set pause reference time, the grain suspension is stopped. In the grain dryer,
The control unit (F) gradually opens the switching valve (22, 23) until the total discharge for a predetermined time range until the elapsed time in the exhaust air circulation drying control reaches the pause reference time, and the exhaust air circulation rate is determined. An exhaust air circulation type grain dryer characterized by performing drying suspension control after being gradually reduced at a predetermined speed.   3. The exhaust air circulation type according to claim 1, wherein the control unit (F) performs exhaust full-close control on the switching valve (22, 23) during the drying pause control. 4. Grain dryer.

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