JP2008185311A5 - - Google Patents

Description

Grain dryer

  The present invention relates to a grain dryer.

Patent Document 1 describes a technique in which exhaust air discharged from an exhaust fan is supplied to a combustion burner side and supplied again to a hot air chamber for use in a drying operation.
JP 2007-10247 A

A large amount of foreign matter and dust are contained in the exhaust air that is exposed to the grains and sucked by the exhaust fan and discharged to the outside of the machine.
The present invention provides a grain dryer for supplying exhaust air discharged from an exhaust fan to a hot air chamber again so that foreign matter and dust contained in the exhaust air discharged from the exhaust fan are not supplied to the hot air chamber as much as possible. This is the issue.

In order to solve the above problems, the present invention has taken the following technical means.
That is, the invention described in claim 1 includes a combustion burner (5), a hot air chamber (11) through which hot air generated by the combustion burner (5) passes, and a grain provided adjacent to the hot air chamber (11). A grain dryer provided with a grain downflow passage (13) and a wind exhaust fan (6) that sucks hot air that has passed through the grain downflow passage (13) and discharges it as exhaust air outside the machine. An exhaust duct (20) is provided on the exhaust side of the wind fan (6), and the exhaust duct (20) exhausts the exhaust air discharged from the exhaust fan (6) to the hot air chamber (11). While connecting the wind circulation passage, the exhaust duct (20) opens and closes around the pivot shaft (23a) so as to adjust the ratio of the exhaust air discharged to the exhaust air circulation passage side and the outside of the machine. The first adjusting plate (23) is provided, and when the first adjusting plate (23) is in the closed position (fb), the exhaust duct (20 Between the inner peripheral surface (20a) and the first adjusting plate (23) of the exhaust area of the gap (Z) first adjusting plate to allow (23) the foreign substances such as dust contained in the exhaust air can pass It is set as the grain dryer characterized by having comprised smaller than the opening area of a wind duct (20).

According to a second aspect of the present invention, the second adjustment plate (22) for adjusting the amount of the exhaust air supplied from the exhaust duct (20) into the exhaust air circulation passage is provided in the exhaust air circulation passage, and the first adjustment is performed. When the plate (23) opens, the second adjusting plate (22) closes, and when the first adjusting plate (23) closes, the second adjusting plate opens the adjusting valve drive motor. The grain dryer according to claim 1 , further comprising a control unit for controlling .

  In the first aspect of the present invention, even when the first control valve (23) is in the closed position (fb) for exhausting the exhaust air to the exhaust air circulation passage side, the exhaust air duct (20). The area of the first adjustment plate (23) is smaller than the opening area of the exhaust duct (20) so that a gap (Z) is formed between the inner peripheral surface (20a) of the first adjustment plate (23). Thus, a large amount of dust can be easily discharged from the gap (Z), and dust supplied into the exhaust air circulation passage can be reduced. Further, since the first adjustment plate (23) can be made smaller, the length of the exhaust duct (20) can be shortened accordingly. Therefore, the front and rear length of the grain dryer can be made compact while the amount of circulating exhaust air can be adjusted.

  In the second aspect of the invention, it is possible to easily adjust the ratio of the exhaust air discharged outside the machine body and the exhaust air supplied into the exhaust air circulation passage.

The grain dryer in which the grain circulates as the best mode for carrying out the invention will be described.
FIG. 1 is a perspective view illustrating the inside of a grain dryer, a storage unit 2 that stores grains from above in a rectangular box 1, and a drying unit 3 that dries the grains stored in the storage unit 2. And a cereal collection unit 4 where the grains dried by the drying unit 3 gather. In the present embodiment, the longitudinal direction s of the box 1 is referred to as the front-rear direction, and the lateral direction t is referred to as the left-right direction.

  Combustion burner 5 accommodated in a burner case 40 in which a large number of slit-like outside air intake ports 50 are formed on the front side at one end in the longitudinal direction s of the box 1, that is, in the front-rear direction and opposite to the drying unit 3, At the other end, an exhaust fan 6 is provided at each of the left and right central positions facing the drying unit 3. Moreover, the elevator 7 which raises a grain is provided in the position which exists in the front-back direction of the box 1 and adjoins the burner case 40, and the grain which was grained by the elevator 7 is provided in the upper part of the box 1 An upper conveyance device 8 that conveys to the storage unit 2 and a dust suction fan 9 that sucks and removes foreign matters such as scum mixed with the grains being conveyed by the upper conveyance device 8 are provided.

Reference numeral 10 denotes a moisture meter that detects the moisture of the grain. The moisture meter 10 is attached to the elevator 7 and takes in the sample grain from the grain that is being fried and detects the moisture.
The drying unit 3 is provided with hot air chambers 11 through which hot air generated by the combustion burner 5 passes at both left and right ends of the box 1, and an exhaust air chamber 12 that communicates with the exhaust fan 6 at the left and right center of the box 1. Between the hot air chamber 11 and the exhaust air chamber 12, a grain flow passage 13 through which the grains of the storage chamber 2 sequentially pass is provided, and the grain is fed to the cereal collection section 4 at the lower end of the grain flow passage 13. A rotary valve 14 is provided.

The grain collecting unit 4 is provided with a lower spiral 15 for conveying the grains to the elevator 7.
The exhaust fan 6 includes an axial centrifugal fan blade 6b and a fixed plate 6c that applies pressure to the exhaust generated by the fan blade 6b inside the circular fan body 6a. A circular exhaust duct 20 is connected to the side.

  A square exhaust air supply duct 21 for supplying exhaust air to the inside of the box 1 is provided at the upper part of the exhaust air duct 20, and the exhaust air inlet of the exhaust air supply duct 21 is supplied into the exhaust air supply duct 21. A second control valve 22 is provided for adjusting the amount of exhausted air.

In the exhaust duct 20, a first control valve 23 that adjusts the ratio of the amount of exhaust air discharged to the outside of the exhaust duct 20 and the exhaust air supply duct 21 is provided.
The 1st control valve 23 and the 2nd control valve 22 are set as the structure rotated by the rotating shaft 23a and the rotating shaft 22a of a horizontal axis, respectively, and the 1st control valve 23 and the 2nd control valve 22 are connected by the connecting rod 24. The first control valve 23 and the second control valve 22 are connected to each other so as to be linked by a control valve drive motor 25. When the second control valve 22 is in the fully closed position ga and exhaust air is not discharged into the exhaust air supply duct 21, the first control valve 23 is in the fully open position fa and all exhaust air is discharged outside the machine.

  On the other hand, when the second control valve 22 is in the fully open position gb and the exhaust air is discharged most into the exhaust air supply duct 21, the first control valve 23 exhausts the most exhaust air. It is located at the closed position fb for discharging the exhaust air to the wind supply duct 21 side. In addition, the 1st control valve 23 and the 2nd control valve 22 are set as the structure which can be opened / closed steplessly, respectively, and the exhaust_gas | exhaustion amount discharged | emitted to the exhaust_gas | exhaustion supply duct 21 is adjusted suitably by the control part (not shown).

  When the first control valve 23 is in the closed position fb that discharges the exhaust air to the exhaust air supply duct 21 side most, the inner peripheral surface 20a of the exhaust air duct 20 and the end of the first adjustment plate 23 The length b from the rotation shaft 23a to the end of the first control valve 23 is shorter than the length from the center of the exhaust duct 20 to the inner peripheral surface 20a so that a gap z with a set interval is formed between the first control valve 23 and The area of one control valve 23 is configured to be smaller than the opening area of the exhaust duct. j is a turning locus of the first control valve 23;

  In addition, the closed position fb where the first control valve 23 discharges the most exhausted air to the exhaust air supply duct 21 side is located at a rearward downward slope as shown in FIG. 22 is configured so as to be inclined forward and downward so that the exhausted air can be easily guided into the exhausted air supply duct 21.

  Between the exhaust air supply duct 21 and the box 1, a case that is an exhaust air distribution passage 26 that distributes the exhaust air that has passed through the exhaust air supply duct 21 to the left and right sides extends over both the left and right sides of the exhaust fan 6. Provide. The left and right ends of the exhaust air distribution passage 26 and the rear end portion of the hot air indoor through passage 27 described later are configured to communicate with each other through a first exhaust air opening m.

  The hot-air chamber through passage 27 is a cylindrical passage provided along the front-rear direction in the left and right hot-air chambers 11 and is formed in a trapezoidal shape with a cross-sectional shape and a sharp upper portion in this embodiment. Between the box 1 and the burner case 40, there are formed a first reduction passage 41 through which exhausted air reduced through circulation in the box 1 passes and a hot air passage 42 through which hot air generated in the combustion burner 5 passes. A heat exhaust passage case 43 is provided. The second end formed on the left and right sides of the first reduction passage 41 and the burner case 40 is configured so that the front end portion of the hot air chamber through passage 27 and the first reduction passage 41 communicate with each other through the second exhaust opening p. The reduction passage 44 is configured to communicate with the third exhaust opening r. A third reduction passage 45 is formed below the burner case 40, and the second reduction passage 44 and the third reduction passage 45 are communicated with each other through a fourth exhaust opening d.

  The hot air passage 42 in the hot exhaust passage case 43 communicates with the third reduction passage 45 via the fifth exhaust passage opening e and communicates with the burner case 40 and the first hot air opening portion c. 46 and a hot air supply passage 47 for supplying the hot air having passed through the hot exhaust air mixing passage 46 from the second hot air opening v to the hot air chamber 11 through the third hot air opening w.

The configuration of the heat exhaust air passage case 43 will be described in detail.
The first reduction passage 41 and the hot air supply passage 47 are formed on the front left and right sides of the box 1 and are formed in two upper and lower stages, and the heat exhaust air mixing passage 46 is on the left and right center side at a position facing the burner case 40. Provided. The first hot air opening c is formed at the center of the hot exhaust air mixing passage 46 and the burner case 40, and the fifth hot air opening e is formed at the lower portion of the hot exhaust air mixing passage 46.

  In the present embodiment, a path through which the exhaust air from the exhaust air supply duct 21 to the third reduction passage 45 passes is generically called an exhaust air circulation passage. The portions of the first reduction passage 41, the second reduction passage 44, and the third reduction passage 45 are called reduction passages.

Next, a process until hot air generated in the combustion burner 5 is exhausted and supplied to the hot air chamber 11 again through the exhaust air circulation passage will be described.
Hot air generated in the combustion burner 5 passes from the burner case 40 through the first hot air opening c, and from the hot exhaust air mixing passage 46 through the second hot air opening v, the hot air supply passage 47, and the third hot air opening w. And supplied to the hot air chamber 11.

  The hot air in the hot air chamber 11 passes through the grain flowing down the grain flow passage 13 that forms a large number of slits (not shown), deprives the grain of moisture and is supplied to the exhaust air chamber 12, and the exhaust fan 6 and is discharged as exhaust air to the exhaust duct 20.

  Exhaust air in the exhaust duct 20 is supplied to exhaust the necessary amount of exhaust air through the exhaust air circulation passage to the hot air chamber 11 again by controlling the opening degree of the first control valve 23 and the second control valve 22. It is supplied to the duct 21.

  The exhaust air supplied to the exhaust air supply duct 21 is dispersed left and right in the exhaust air distribution passage 26 and supplied to the hot air indoor through passage 27 from the first exhaust air opening m. And, the exhaust air in the hot air indoor through passage 27 is discharged from the second exhaust opening p to the first reduction passage 41, the third exhaust opening r, the second reduction passage 44, the fourth exhaust opening d, the third. It is supplied to the heat exhaust air mixing passage 46 through the reduction passage 45 and the fifth exhaust air opening e. Therefore, it is mixed with hot air and supplied to the hot air chamber 11 through the hot air supply passage 47.

  The mixed air of exhaust air and hot air supplied to the hot air chamber 11 is in a high temperature and high humidity state because the heat and moisture contained in the exhaust air are added to the hot air, and when this is exposed to the grain, While rapidly raising the grain temperature by the action of high heat, the moisture that is about to be vaporized rapidly from the inside of the grain due to the rise in grain temperature is vaporized while being suppressed by the moisture in the mixed air, thereby rapidly increasing the moisture content in the grain. It is possible to efficiently remove the moisture in the grain and prevent the grain from being cracked due to slow movement, that is, vaporization.

Next, effects generated from the configuration of the present embodiment will be described.
When the first control valve 23 is in the closed position fb that discharges the exhaust air to the exhaust air supply duct 21 side most, the inner peripheral surface 20a of the exhaust air duct 20 and the end of the first adjustment plate 23 By configuring the area of the first adjusting plate 23 to be smaller than the opening area of the exhaust duct 20 so that a gap z is formed between the exhaust duct 20 and the air gap 23b, relatively large dust contained in the exhaust air is removed from the exhaust duct 20 from the gap z. It becomes easy to be discharged outside the machine, dust can be made difficult to accumulate in the exhaust air circulation passage from the exhaust air supply duct 21 to the third reduction passage 45, and the exhaust air can be passed smoothly. . Further, since the exhaust air supply duct 21 is located above the exhaust air duct 20, it is difficult for large dust to enter the exhaust air supply duct 21 and to be easily discharged outside the apparatus.

  By providing the hot air chamber through passage 27 in the hot air chamber 11, the temperature inside the hot air chamber through passage 27 is also increased, and high-humidity exhaust air containing dust is condensed inside the hot air chamber through passage 27 and dust is deposited. Can be prevented. In addition, if a passage for passing the exhaust air is provided in the exhaust air chamber 12, the space of the exhaust air chamber 12 is reduced and the suction force of the exhaust air fan 6 is reduced. However, by providing it in the hot air chamber 11. This can be prevented by this embodiment.

  By providing the hot air chamber 11 on both the left and right sides of the box 1 and the exhaust air chamber 12 at the center of the box 1, a high temperature and high humidity mixed gas in which the exhaust air and hot air are mixed when the outside air temperature is low. Can be prevented from condensing in the exhaust chamber 12 through which the exhaust passes.

  Before the exhaust air is supplied to the hot exhaust air mixing passage 46 from the hot air interior passage 27, the combustion surface of the combustion burner 5 passes through the reduction passage from the first reduction passage 41 adjacent to the burner case 40 to the third reduction passage 45. By supplying to the opposing heat exhaust air mixing passage 46, deterioration of the combustion burner 5 due to direct exposure of exhaust air to the combustion burner 5 can be prevented. Further, by providing the third reduction passage 45 at a position lower than the heat exhaust air mixing passage 46 in the reduction passage, the exhaust air is dropped from the first reduction passage 41 toward the third reduction passage 45 and then the heat exhaust air. Since it rises toward the mixing passage 46, it becomes possible to accumulate a large amount of dust being exhausted in the third reduction passage 45, and the amount of dust supplied to the hot exhaust air mixing passage 46 and the hot air chamber 11 is reduced. Can be made. By providing the reduction passage adjacent to the burner case 40, the heat retention of the exhaust air can be improved.

Next, the control method of the opening degree of the 1st control valve 23 and the 2nd control valve 22 is demonstrated.
Absolute humidity calculated by a control unit (not shown) when the outside air temperature detected by an outside air temperature sensor (not shown) is 20 ° C. and the outside air humidity detected by an outside air humidity sensor (not shown) is 70%. Z) is 13 g / m3. The exhaust air (Y) as a control target is, for example, a case where the exhaust air temperature is 30 ° C., the exhaust air humidity is 70%, and the absolute humidity (U) is 25 g / m 3. And the air volume of the exhaust fan 7 of a present Example is 1900 kg / h, the quantity of the grain (rice cake) supplied to the grain dryer is 800 kg, and a drying rate (ratio of the moisture dried per hour) Is 1.2% / h, the rate of exhaust air to be reduced to the hot air chamber 13 is obtained from the following equation.

Absolute humidity (U)-Absolute humidity (Z) = 12 (g / m3) (a)
The maximum amount of water that can be absorbed by outside air is 12 x 1900/1000 ≒ 23 (kg) (B)
The amount of water removed from the dryer per hour is 800 (kg) × 1.2 (% / h) = 9.6 (kg / h) (C)
From the formulas (b) and (c), 23 / 9.6 + 23≈0.71 → 71% (2)
That is, the first control valve 23 and the second control valve 22 are adjusted so that 71% of the exhausted air amount discharged from the exhaust air fan 7 is reduced to the hot air chamber 11.

  In addition, when the 1st control valve 23 and the 2nd control valve 22 are adjusted so that more than 71% of exhaust air volume may be returned to the hot air chamber 11, the amount of water | moisture content reduce | restored increases, so that it increases. For this reason, it becomes difficult to remove moisture from the grain. Further, when the first control valve 23 and the second control valve 22 reduce an amount less than 71% of the exhausted air amount to the hot air chamber 11, the amount of heat reduced to the hot air chamber 11 decreases, so that the temperature of the grain is reduced. It is difficult to rise and the drying speed is slow.

  By adjusting the ratio of reduction to Equation 1 of the present embodiment, the heat generated by the exhaust air discharged from the exhaust air fan 6, that is, the drying operation with good combustion efficiency can be performed by using the water absorption force as appropriately as possible. It can be carried out.

The drying control according to the present embodiment will be described in more detail. The outside air temperature sensor and the outside air humidity sensor detect the outside air temperature and humidity, the control unit calculates the outside air absolute humidity, and the outside air absolute humidity and the grain. Comparing the absolute humidity of the exhaust air at the relative humidity and the temperature to compare with the absolute humidity of the exhaust air set in advance from the conditions of moisture and the absolute humidity of the outside air Calculated as water absorption. On the other hand, the amount of water evaporated from the dryer by the drying operation (in this embodiment, the amount of water removed from the dryer per one hour as described above) was obtained, and the increased amount of water was added to the amount of water evaporated by the drying operation. The ratio to the value is considered as the ratio that can reduce the exhaust air. That is, the above formula (d) is the amount of increased water / increasing water amount + evaporated water amount.
Is shown.

  In conventional hot air drying, every time the moisture on the surface of the grain is removed, the moisture inside the grain is dried by utilizing the property that the water moves using heat conduction to sequentially appear on the surface of the grain. In the exhaust air drying according to the present embodiment, the moisture difference between the grain surface and the inside increases when the drying is rapidly performed at a high temperature in order to perform high-speed drying. By simultaneously reducing the heat and moisture contained in the exhaust air to the hot air chamber (11), the moisture to be removed from the grain surface is suppressed by the moisture contained in the exhaust air, and the moisture inside the kernel While making the grain difficult to break by making the gradient constant, the grain temperature is raised in a short time by giving extra heat during exhaust air, thereby enabling high-speed drying.

The perspective view explaining the inside of a grain dryer The perspective view explaining the structure of a drying part and a grain collection part Front view illustrating the configuration of the drying unit and the cereal collecting unit Side view explaining the interlocking configuration of the first control valve and the second control valve A perspective view showing an exhaust air supply duct, an exhaust air dispersion passage, and an exhaust fan The perspective view explaining the inside of a burner case and a heat exhaust air passage case

5 Combustion Burner 6 Exhaust Fan 11 Hot Air Chamber 13 Grain Flow Down Passage 20 Exhaust Duct 22 Second Adjustment Plate 23 First Adjustment Plate 23a Rotating Shaft 24 Rod

Claims (2)

A combustion burner (5), a hot air chamber (11) through which hot air generated in the combustion burner (5) passes, a kernel flow passage (13) provided adjacent to the hot air chamber (11) and through which the kernel flows down, In a grain dryer provided with an exhaust fan (6) that sucks hot air that has passed through the grain flow passage (13) and exhausts it as exhaust air to the outside of the machine,
An exhaust duct (20) is provided on the exhaust side of the exhaust fan (6), and exhaust air exhausted by the exhaust fan (6) is supplied to the exhaust duct (20) to the hot air chamber (11). The exhaust air circulation passage is connected, and the rotation shaft (23a) is opened and closed about the center of the exhaust air duct (20) so as to adjust the ratio of the exhaust air discharged to the exhaust air circulation passage side and the outside of the machine. A first adjusting plate (23) that operates,
When the first adjustment plate (23) is in the closed position (fb), dust or the like contained in the exhaust air is placed between the inner peripheral surface (20a) of the exhaust duct (20) and the first adjustment plate (23) . A grain dryer characterized in that the area of the first adjustment plate (23) is smaller than the opening area of the exhaust duct (20) so that a gap (Z) through which foreign matter can pass is formed. A second adjusting plate (22) for adjusting the amount of exhaust air supplied from the exhaust duct (20) into the exhaust air circulation passage is provided in the exhaust air circulation passage, and the first adjusting plate (23) opens. A control unit is provided for controlling the control valve drive motor that performs the closing operation of the second adjusting plate (22) when opening, and the second adjusting plate (23) opening when the first adjusting plate (23) is closed. The grain dryer according to claim 1.