JP6933089B2 - Crop dryer - Google Patents

Description

The present invention relates to a crop dryer for drying grains and other agricultural products.

As a combustion control method in various devices having a combustion burner, a configuration is known in which intermittent combustion is performed at a small required heat load and proportional combustion is performed at a large required heat load (Patent Document 1). Further, in a grain dryer, a far-infrared dryer equipped with a far-infrared radiator and drying grains with radiant heat while heating with a combustion burner is known (Patent Document 2).

Japanese Unexamined Patent Publication No. 3-282116 Japanese Unexamined Patent Publication No. 2016-118305

However, in the technique of Patent Document 1, since the combustion burner is controlled for intermittent combustion, it is possible to realize a state of lower heating and heating than continuous combustion in the intermittent combustion state, and a single burner can increase the combustion width. It is excellent in that it can be taken. However, since it is accompanied by a burner stop, the heating and heating change abruptly, and depending on the properties of the direct or indirect drying object of heating and heating, for example, in the case of a grain dryer, the quality of the target grain deteriorates. May come. Further, in the technique of Patent Document 2, since the combustion burner and the far-infrared radiator are closely arranged in the far-infrared dryer, the radiant heat generated from the far-infrared radiator is irradiated to the combustion burner and adversely affects the accessory parts and the like. There is a fear.

The present invention is intended to eliminate the above-mentioned drawbacks by applying intermittent combustion control of a combustion burner to a far-infrared dryer.

The present invention has taken the following technical measures to solve the above problems.

The first invention is a combustion burner (7) having a hot air chamber (14), an exhaust chamber (8), a blower fan (52) for a burner for supplying combustion air, and a nozzle (49) for supplying fuel. ), A far-infrared radiator (16) facing the combustion surface of the combustion burner (7) and inside the hot air chamber (14) to irradiate the crop with far-infrared rays, and flowing into the exhaust chamber (8). In a crop dryer equipped with an exhaust fan (10) for discharging the hot air to the outside of the machine, the combustion burner (7) performs an intermittent combustion operation in which a combustion step and a stop step are alternately performed, and a fuel supply amount. A variable proportional combustion operation is operably provided, the intermittent combustion operation is performed in a region equal to or less than a preset reference fuel supply amount (Fa), and the proportional combustion operation is performed with the reference fuel supply amount (Fa). It is a crop dryer configured to be performed in a region exceeding the range, and to continuously operate the burner blower fan (52) even during the stop step of the intermittent combustion operation.
The second invention has a configuration in which the rotation speed of the blower fan (52) for the burner is changed according to the fuel supply amount during the proportional combustion operation, and is set to a predetermined low rotation speed during the intermittent combustion operation. This is the first crop dryer of the present invention configured.
The third invention is the first or second crop dryer of the present invention configured to operate the burner blower fan (52) in a predetermined high rotation region for a predetermined time after the completion of the drying operation. be.
In the fourth aspect of the present invention, during the drying operation in which the combustion burner (7) executes the intermittent combustion operation, a pause drying operation for stopping the combustion burner (7) is operably provided, and the pause drying operation is in progress. The first to third crop dryer of the present invention is configured to operate the burner blower fan (52) in a low rotation region of a predetermined value or less for a predetermined time.
A fifth aspect of the present invention is to provide a pause drying operation for stopping the combustion burner (7) during the drying operation in which the combustion burner (7) executes the proportional combustion, and during the pause drying operation. The crop dryer of the present invention according to any one of the first to the fourth, wherein the blower fan (52) for a burner is operated in a high rotation region of a predetermined value or higher for a predetermined time.
The sixth invention is provided with a hot air temperature detection sensor (43), and has a configuration in which the hot air temperature average value (MRn, MIN) is calculated and displayed, and the hot air temperature average value (MIN) during the intermittent combustion operation is described above. The first to fifth, which are configured to be calculated based on the detected values during the combustion process, and display and output the hot air temperature average value (MRn, MIN) during the proportional combustion operation or the intermittent combustion operation in a common period (Td). Any one of the dryers for crops of the present invention.
The first invention related to the present invention is a combustion burner 7 provided with a blower fan 52 for a burner that supplies combustion air and a nozzle 49 that supplies fuel, and a combustion burner 7 that faces the combustion surface of the combustion burner 7 and is far from the crop. In a crop dryer equipped with a far-infrared radiator 16 that irradiates infrared rays, the combustion burner 7 executes an intermittent combustion operation in which a combustion step and a stop step are alternately performed, and a proportional combustion operation in which a variable fuel supply amount is performed. The intermittent combustion operation is configured to be possible, the intermittent combustion operation is performed in a region equal to or less than a preset reference fuel supply amount Fa, and the proportional combustion operation is performed in a region exceeding the reference fuel supply amount Fa, and the intermittent combustion operation is performed. The burner blower fan 52 is configured to operate even during the stop step of the above.

Second invention relating to the present invention, in the first invention relating to the present invention, the at proportional combustion operation, the rotational speed of the burner blower fan 52 is configured to be changed according to the fuel supply amount, During the intermittent combustion operation, it is set to a predetermined low rotation region.

The invention described in the third related to the present invention, the operation in the first or second invention relating to the present invention, over the completion of the drying operation after a predetermined time, the burner blower fan 52 at a predetermined high speed region do.

The invention described in the fourth relating to the present invention, in the first related to the present invention a third any one of the invention, the drying operation the combustion burner 7 is to perform the proportional combustion operation or the intermittent combustion operation A pause drying operation for stopping the combustion burner 7 is executably provided in the middle of the operation, and the burner blower fan 52 is operated in a predetermined low rotation region during the pause drying operation.

The invention described in the fifth related to the present invention, in the first related to the present invention the fourth any one of the inventions, during the combustion burner (7) is drying operation to perform the proportional combustion, A pause drying operation for stopping the combustion burner (7) is operably provided, and the burner blower fan (52) is operated in a high rotation region equal to or higher than a predetermined value during the pause drying operation.

The invention described in the sixth associated invention, in the first related to the present invention the fifth any one of the inventions, including a hot air temperature detection sensor 43, a hot air temperature of an average value MRn, to calculate the MIn The hot air temperature average value MIN during the intermittent combustion operation is calculated based on the detected value during the combustion process, and the hot air temperature average values MRn and MIN during the proportional combustion operation or the intermittent combustion operation are displayed. Display and output with a common period Td.

According to the present invention, adverse effects such as breakage can be reduced.
According to the first invention relating to the present invention, since the intermittent combustion operation is performed by the fuel supply amount Fa following areas criteria set in advance, when the intermittent combustion operation not only during the combustion process is stopped Since the operation of the blower fan 52 for the burner is continued in the process, the combustion burner 7 is operated by the operation of the blower fan 52 for the burner even if the radiant heat of the far infrared radiator 16 during the stop process is irradiated in the direction of the combustion burner 7. Overheating of the side nozzle 49 and the like can be suppressed, and adverse effects such as breakage can be reduced.

According to the second invention relating to the present invention, in addition to the effects of the first invention relating to the present invention, the at proportional combustion operation is changed according to the rotational speed of the burner blower fan 52 to the fuel supply amount Since it is configured, a good combustion state can be maintained. Further, since it is set in a predetermined low rotation region during the intermittent combustion operation, it is possible to prevent an ignition failure at the time of transition from the stop process to the combustion process.

According to the third invention relating to the present invention, in addition to the effect of the first or second invention relating to the present invention, completion of the drying operation after a predetermined between the high rotation area for the blower fan 52 reaches a predetermined burner Since it is operated in, the combustion burner 7 can be cooled quickly.

According to the fourth or fifth invention related to the present invention, it is possible to appropriately shift to pause the drying operation.

According to the sixth invention related to the present invention, in addition the first relating to the present invention to the effect of the fifth invention, the average value MRn detected hot wind temperature, MIn during proportional combustion operation or in an intermittent combustion operation Regardless of the period, it is displayed with a common period Td, so that it is easy for the operator to visually recognize.

It is a front sectional view of a grain dryer. It is a side sectional view of the drying chamber and the grain collecting chamber of a grain dryer. It is a front view of the operation panel. It is a control block diagram. It is a graph of the combustion amount-fan rotation speed relation. It is a flowchart. It is a flowchart. (A) is a time chart of proportional combustion operation, and (B) is a time chart of intermittent combustion operation. It is a graph of the combustion amount-fan rotation speed relation. It is a time chart. It is a graph of the combustion amount-fan rotation speed relation. It is a flowchart. It is a time chart of intermittent combustion operation.

A grain dryer as an embodiment of the present invention will be described with reference to the drawings.

Inside the box 1, a storage chamber 2 for storing grains from the top to the bottom, a drying chamber 3 for drying grains, and a grain collection chamber 4 are provided.

An elevator 5 for raising grains and a burner case 6 are provided on the front side of the box body 1, and a combustion burner 7 for generating hot air is provided in the burner case 6. An exhaust duct 9 communicating with the exhaust chamber 8 is provided on the rear side of the box body 1, and an exhaust fan 10 is provided on the rear side surface of the exhaust duct 9. One end end side of the exhaust air return duct 11 is connected to the upper surface of the exhaust fan 10, and the other end end side of the exhaust air return duct 11 is connected to the box body 1. The exhaust air inlet 12 of the exhaust air return duct 11 communicates with the inside of the exhaust fan 10, and the exhaust air supply port 13 on the terminal side communicates with the upper rear side of the hot air chamber 14 described later.

An upper spiral gutter 15 for laterally transporting grains fried by the elevator 5 is provided on the upper part of the box body 1.

In the drying chamber 3 below the storage chamber 2, a pair of Y-shaped grain flow passages 19 having a cross section for further dividing the grains in the storage chamber 2 divided into left and right are formed. In the upper half of the drying chamber 3, a pair of left and right secondary ventilation chambers 8a are formed on the upper side. Further, hot air chambers 14 are provided in the left and right central portions of the drying chamber 3, and far infrared radiators 16 are provided inside the hot air chamber 14 so as to be in the front-rear direction. The grain flow passages 19 and 19 through which grains flow down are arranged on the left and right sides of the hot air chamber 14, and exhaust vent chambers 8 and 8 are provided on the left and right outside of the grain flow passages 19 and 19.

A rotary valve 17 for delivering grain is provided at the left and right confluences at the lower end of the grain flow passage 19, and a lower spiral 18 for transporting grain to the elevator 5 is provided below the rotary valve 17.

The burner case 6 forms a large number of outside air intake slits for taking in outside air. In the present embodiment, the combustion burner 7 is equipped with an intermittent combustion type gun type burner 7.

The exhaust fan 10 includes a rotary blade 20 that rotates in the outer cylinder 24 by a rotary shaft 20a having a horizontal axis along the front-rear direction, a fixed blade 21 that rectifies the exhaust air discharged from the rotary blade 20, and a rotary blade. It is composed of an inner cylinder 25 that pivotally supports the 20 and an exhaust guide plate 22 that guides the exhaust air discharged by the rotary blade 20 to the exhaust return duct 11 side.

The fixed blades 21 are located behind the rotary blade 20 on the exhaust side, and are provided with twist-shaped exhaust air rectifying surfaces on both the left and right sides, and are provided in large numbers at set intervals radially in rear view. The outer end of the fixed wing 21 is attached to the outer cylinder 24, and the inner end of the fixed wing 21 is attached to the inner cylinder 25.

An exhaust air control valve 26 for increasing or decreasing the amount of exhaust air flowing into the exhaust air return duct 11 is provided in the exhaust air return duct 11. The exhaust air control valve 26 is configured by an exhaust air control valve motor 27 so that the rotation angle can be adjusted around the center of the horizontal axis in the left-right direction. The exhaust air return duct 11 is a second duct extending in the front-rear direction connecting the first duct portion 11a extending upward from the upper surface of the exhaust fan 10 and the upper end portion of the first duct portion 11a and the back surface of the box body 1. It is composed of a portion 11b, and an exhaust air control valve 26 is provided in the first duct portion 11a. The second duct portion 11b has a configuration in which the opening area is gradually increased in a front-spreading manner.

The far-infrared radiator 16 is composed of a large-diameter first cylindrical portion 30 and a small-diameter second cylindrical portion 31. The rear portion of the first cylindrical portion 30 is formed as a narrowed portion 30a, and the second cylindrical portion 31 is connected to the narrowed portion via a bent portion on the starting end side to guide the second cylindrical portion 31 upward and is folded back and connected to the front side. Both the first cylindrical portion 30 and the second cylindrical portion 31 are hollow, and the second cylindrical snapper 31 is arranged above the first cylindrical portion 30 in parallel in the front-rear direction via a predetermined space.

The front end opening of the first cylindrical portion 30 is arranged to face the combustion portion of the combustion burner 7, the front end of the second cylindrical portion 31 is closed by a plate body, and both left and right sides are on the lower front side, which is the terminal side of the second cylindrical portion 31. Openings 31a that open toward the surface are provided at predetermined intervals.

An operation panel U incorporating a control unit S is provided on the front surface of the burner case 6. As shown in FIG. 3, each operation switch of the tension switch 32, the ventilation switch 33, the drying switch 34, the discharge switch 35, and the stop switch 36 is provided on the front side of the operation panel U. Further, a liquid crystal display operation display panel 45 is provided for sequentially switching and displaying the hot air temperature during the drying operation, the measured moisture value, and the remaining time until the end of the drying operation.

In addition, the setting display panel 39 for displaying the setting values of the filling amount switch 37 for setting the filling amount, the moisture setting switch 38 for setting the target moisture value, the filling amount switch 37 and the moisture setting switch 38, and the setting. A numerical value increase / decrease switch 40 for changing the set value of the display panel 39 is provided. Further, a grain setting switch 41 for setting the type of grain to be dried and a drying speed setting switch 42 for setting the drying speed are provided.

The hot air chamber 14 is provided with a hot air temperature detection sensor 43 for detecting the temperature inside the hot air chamber 14, and an outside air temperature sensor 44 for detecting the outside air temperature is provided at an appropriate position on the operation panel U.

As shown in FIG. 4, various switches and sensors are connected to the input side of the control unit S via an input interface, and various motors and drive means are connected to the output side via an output interface.

Next, combustion control and drying control by the exhaust air control valve 26 will be described.

The combustion burner 7 of the present embodiment is a so-called gun type burner, in which combustion air is supplied by a burner blower fan 52, fuel discharged from a fuel tank (not shown) by a pump 50 is sprayed from a nozzle 49, and an igniter is used. Ignite and burn at 51. The amount of fuel supplied from the pump 50 to the combustion burner 7 can be controlled by the proportional control valve 53, and the grain type, the difference between the drying rate set in advance by the setting switch 42 and the actual drying rate, and the outside air temperature. Based on the above, the control unit S calculates the required combustion amount of the burner every predetermined unit time, calculates the fuel supply amount corresponding to this, and outputs the fuel supply amount command signal to the proportional control valve 53. .. The combustion burner 7 is based on the fuel supply amount Fa (liter / hour) preset according to the performance unique to the device, and when a larger fuel supply amount is required, the proportional control valve is described above. Based on the control signal given to 53, the required fuel supply amount Fb is calculated (proportional combustion operation). However, when the fuel supply amount Fa or less of the reference is required, the combustion burner 7 is switched to the so-called intermittent combustion operation in which the combustion step and the combustion stop step are alternately performed. Then, the combustion state of the reference fuel supply amount Fa or less can be adjusted by changing the combustion process time Tb and the stop process time Ts while keeping the cycle T (for example, 60 seconds) of the combustion process and the stop process in the intermittent combustion operation constant. It has a structure.

As shown in the combustion amount-fan rotation speed relationship graph of FIG. 5, in the proportional combustion operation of the combustion burner 7, the rotation speed of the blower fan 52 for the burner also increases or decreases in proportion to the change in the amount of fuel supply. It has a controlled configuration. Further, during the intermittent combustion operation, in the combustion process, the minimum rotation speed Ra in the combustion amount-fan rotation speed table is selected and rotation control is performed. In the stop step in the intermittent combustion operation, the burner blower fan 52 is continuously rotated and interlocked during the intermittent combustion operation as a configuration in which a preset rotation speed is selected and rotated. The fan rotation speeds of the combustion step and the stop step in the intermittent combustion operation may be the same rotation speed or different rotation speeds.

Next, the grain drying operation will be described.

When the operator turns on the stake switch 32, the elevator 5 and the upper spiral 15 are driven to sequentially squeeze the stake grain into the storage chamber 2. Then, when the filling operation is completed, the operator sets the filling grain amount with the filling amount switch 37, sets the reaching target moisture value (for example, 14%) with the moisture setting switch 38, and targets with the grain setting switch 41. The grain is set, and the drying rate is set with the drying rate setting switch 42.

Next, when the drying switch 34 is turned on, the drying operation is started, the circulation system of the rotary valve 17, the lower spiral 18, the elevator 5, and the upper spiral 15 is started to be driven, and the combustion burner 7 is started to burn. The hot air generated by the combustion burner 7 passes through the inside of the far-infrared radiator 16 by the suction action of the exhaust fan 10, and enters the hot air chamber 14 from the openings 31a, 31a ... Inflow. Then, it flows from the hot air chamber 14 into the grain flow passage 19 formed of a net body and acts on the grain. Then, the hot air that has deprived the grains of water flows into the exhaust chamber 8, and then is discharged as exhaust air to the outside of the machine by the exhaust fan 10 through the exhaust duct 9.

A part of the exhaust air with heat and moisture is supplied to the hot air chamber 14 via the exhaust air return duct 11 and reused for the drying operation. The grain is dried by the action of hot air, far infrared rays generated from the far infrared radiator 16, and the exhaust air returned from the exhaust air return duct 11.

The exhaust air control valve 26 is adjusted based on the set amount of grain and drying rate, the grain moisture value measured by the moisture meter 54, the outside air temperature, and the like. For example, in the initial stage of drying, the ratio of returning the out-of-machine exhaust air to the exhaust air return duct 11 side is increased in order to raise the grain temperature, and as the drying operation is continued, the moisture value measured by the moisture meter 53 decreases. The rate of returning to the air return duct 11 side is gradually reduced, and the air exhaust control valve 26 is controlled so that almost all the exhaust air is discharged to the outside of the machine when the target moisture value is approached.

In the present embodiment, even when the exhaust air control valve 26 is fully opened, that is, even when the largest amount of exhaust air is supplied to the hot air chamber 14 through the exhaust air return duct 11, the exhaust air is a slit of the exhaust air guide plate 22. Since it passes through 22a and between the fixed blades 21 of the portion where the exhaust air guide plate 22 is not attached, the ratio of the return air exhaust supplied to the hot air chamber 14 is about 4 of the total external air exhaust volume. It's about a percentage.

Next, based on the flowchart of FIG. 6, the burner operation control in which the combustion burner 7 operates in proportional combustion operation or intermittent combustion operation will be described. When the drying switch 34 is turned on, the status of each part switch and the sensor is read (S101, S102). The control unit S calculates the fuel supply amount F based on the grain type, the moisture value, the drying speed, and the like, and the calculated fuel supply amount F is compared with the preset reference fuel supply amount Fa. When the calculated fuel supply amount F exceeds the standard fuel supply amount Fa (S103), a fuel supply signal corresponding to the calculated fuel supply amount F is output to the proportional control valve 53 (S104), and for a burner as described later. The rotation speed of the blower fan 52 is calculated, and the proportional combustion operation BL is executed (S106). On the other hand, when the fuel supply amount F calculated in S103 is equal to or less than the reference fuel supply amount Fa, a supply signal of the minimum fuel supply amount Fmn preset in advance is output to the proportional control valve 53 (S107), and a blower fan for the burner. The rotation speed of 52 is set in a low region and is output to rotate (S108). Further, the combustion process time Tb with respect to the period T is calculated (S109), and the intermittent combustion operation is executed (S110). In this way, based on the comparison between the calculated fuel supply amount F and the standard fuel supply amount Fa, it is determined whether to perform proportional combustion operation or intermittent combustion operation. The heating condition can be changed and adjusted in a wide range over a high combustion range.

In FIG. 6, when the stop switch 36 is turned on or when the moisture value reaches the target moisture value, the combustion burner 7 and each operating part are stopped (S111, S112), but the blower fan 52 for the burner is rotated and output in a high region. , The fan 52 continues to operate for a predetermined time (S113 to S115). When the stop switch 36 is turned on, S112 to S115 are executed together regardless of whether it is a proportional combustion operation or an intermittent combustion operation. With this configuration, the combustion burner can be cooled quickly.

Next, the control of the blower fan 52 for the burner will be described with reference to FIG. 7. After operating the drying switch 34ON, the control unit S determines whether the operation of the combustion burner 7 is the proportional combustion operation or the intermittent combustion operation (S201, S202), and when it is determined that the operation is the proportional combustion control, the calculated fuel is obtained. The supply amount F is read (S203). Then, the combustion amount-fan rotation speed relationship graph as shown in FIG. 5 is called from the memory (S204). The fan rotation speed is calculated from the combustion amount-fan rotation speed relationship graph, and the rotation speed is output to the blower fan motor 55 that drives the blower fan 52 for the burner (S205 to S207).

When the intermittent combustion operation is determined in S202, it is determined whether the combustion process or the stop process is performed (S208). When it is determined that the combustion process is performed, the fuel supply amount is read below (S209), and the combustion amount-fan speed relationship graph is called from the memory (S210). The minimum fan rotation speed Rmn is calculated from this combustion amount-fan rotation speed relationship graph (S211), and the rotation speed is output to the drive motor 55 that drives the burner blower fan 52 (S212). Then, the burner blower fan 52 is rotated until the combustion process time Tb elapses (S213, S214). When the stop process is determined in S208, the fuel supply to the combustion burner 7 is cut off and the combustion is stopped. However, the rotation speed preset and stored as the fan rotation speed, for example, the minimum fan rotation speed Rmn is called, and the burner is burned. The blower fan 52 is rotated until the stop process time Ts elapses (S215 to S218).

After that, when the operation of the stop switch 36 is turned on or the product is dried to the desired moisture value, the combustion burner 7 is stopped (S219, S210), and thereafter, S112 to S115 in FIG. 6 are executed (S220 to S223).

Whether the combustion burner operation of S202 is a proportional combustion operation or an intermittent combustion operation is determined based on whether or not the calculated fuel supply amount exceeds the reference fuel supply amount, and the combustion of S208 is performed. The determination of whether the process is a step or a stop step is determined to execute the combustion step immediately after the lapse of time in S218, and to execute the combustion step immediately after the lapse of time in S214.

By the way, in the drying control, there is a drying control method in which a pause drying operation is performed in the middle of a normal drying operation for the purpose of eliminating uneven drying. In the pause drying operation, the combustion burner 7 is stopped, and the burner blower fan 52 is configured to continue operation for a predetermined time in a predetermined rotation region during the pause drying operation. At this time, if the combustion immediately before the pause drying operation is the intermittent combustion operation, the burner blower fan 52 operates in a low rotation region of a predetermined value or less for a predetermined time, and in the case of the proportional combustion operation, the height is higher than the predetermined value. The operation is performed for a predetermined time according to the rotation region. Therefore, it is possible to smoothly shift to dormant drying.

The time chart shown in FIG. 8 shows the status of the hot air temperature averaging process and the display output of the proportional combustion operation and the intermittent combustion operation. FIG. 8A shows the display output of the fuel supply amount, the hot air temperature, the moving average value MRn (n = 1, 2, ...) Of the hot air temperature and the moving average value MRn during the proportional combustion operation, and shows a predetermined period. The display of the moving average value MRn is updated for each Td. On the other hand, FIG. 8B shows an example of the fuel supply amount, the hot air temperature, the moving average value MIN (n = 1, 2, ...) And the moving average value MIN display during the intermittent combustion operation.

The moving average value display is executed for each cycle Td in both the proportional combustion operation and the intermittent combustion operation. Therefore, regardless of whether the proportional combustion operation or the intermittent combustion operation is in progress, the operator only has to remember this common cycle Td, and when determining the abnormality determination or the like, the next time the visual inspection is not missed and the determination of the abnormality or the like is made quickly. Can be done.

Then, the moving average value MRn or MIN immediately before the display output timing according to the period Td is adopted and displayed on the operation display panel 45. By the way, the moving average value MIN during the intermittent combustion operation is calculated as follows. The detection data from the hot air temperature detection sensor 43 is only during the combustion process, and the detection data during the stop process is not adopted. The moving average value MIN is displayed for each cycle Td, but the moving average value MIN immediately before the display output timing according to the cycle Td is adopted and displayed on the operation display panel 45. The values of MI1 and MI5 in FIG. 8B are immediately displayed, but the values of MI3 and MI7 are continuously displayed. The arrow in FIG. 8B shows the relationship of adoption and display based on the display output.

As shown in FIG. 13, a simple average value may be adopted instead of the moving average value. In this case, for example, the average temperature may be measured during the combustion process during the intermittent combustion operation and displayed and output during the stop process.

The example of FIG. 9 shows the case of kerosene fuel which is standardly used for the combustion burner 7 of the crop dryer, but light oil can be used instead of kerosene. The graph of the combustion amount-fan rotation speed relationship when using light oil is shown by the dotted line in FIG. In the case of light oil having high viscosity, the fan speed is set slightly higher than that of kerosene (solid line in FIG. 11). Further, the minimum fuel supply amount Fmn sets the minimum fuel supply amount F'mn of light oil to be slightly larger than the minimum fuel supply amount Fmn of kerosene. That is, in the case of highly viscous light oil, it is possible to prevent fuel clogging of the nozzle 49 by limiting the fuel supply state on the lowest side.

In this embodiment, since the execution of the minimum fuel supply amount Fmn or F'mn is during the intermittent combustion operation, in the case of light oil, the combustion process time Tb is positively corrected as compared with the case of kerosene, and the fuel is fueled. The supply amount is different. When the intermittent combustion operation is not adopted, the same configuration can be made even during the proportional combustion operation.

As described above, the minimum fuel supply amount Fmn is set to have a slightly larger minimum fuel supply amount F'mn of light oil than the minimum fuel supply amount Fmn of kerosene, and there is a difference of ΔFmn. Therefore, in the case of light oil having high viscosity, it is possible to prevent fuel clogging of the nozzle 49 by setting the fuel supply state on the lowest side to be higher by ΔFmn than kerosene.

The control unit S includes a kerosene / light oil selection switch 46, and when kerosene is selected and set, the solid line side of the combustion amount-fan rotation speed in FIG. 11 is adopted, and fuel supply amount control and fan rotation speed control corresponding thereto are adopted. Is executed, and when light oil is selected and set, the dotted line side in FIG. 11 is adopted. The fuel supply amount control is based on the fuel supply signal from the control unit S to the proportional control valve 53 of kerosene or light oil selected for the nozzle 47, and the fan rotation speed control drives the burner blower fan 52. This is due to the output of the fan rotation speed signal from the control unit S to the blower fan motor 55.

FIG. 12 describes fuel selection and drying control. The drying switch 34 is turned on to read the status of each part switch and sensor (S201, 202). Among the switches, the selection output of the kerosene / light oil selection switch 32 is input (S203). At the start of drying, the initial fuel supply amount and the initial fan speed are called in advance (S204, S205). In this state, the initial combustion operation, that is, the combustion burner 7 is ignited and burned (S206). At the same time, based on the input of S203, it is determined whether or not the selected fuel is kerosene selection (S207), and when kerosene is selected, the solid line side indicating kerosene out of the combustion amount-fan rotation speed in FIG. Proportional combustion operation or intermittent combustion operation is executed depending on the amount (S209).

When it is determined in S207 that the light oil is selected, the dotted line side indicating the light oil out of the combustion amount-fan rotation speed in FIG. 11 is adopted (S210), and the combustion burner 7 or the like is operated.

During the drying operation while the combustion burner 7 is operating, the fuel supply amount F is calculated from the difference between the hot air temperature Tb by the hot air temperature detection sensor 43 and the preset hot air temperature Tc (S211 and S212). It is determined whether the fuel supply amount F calculated here is the minimum fuel supply amount Fmn of kerosene or the minimum fuel supply amount F'mn of light oil (S213, S214), and the supply is output (S215, S216). ). If it is not the minimum fuel supply amount in S213, the calculated supply amount F is output (S217).

Then, when the grain moisture reaches a predetermined finish moisture or the stop switch 36 is turned ON (S218), the combustion burner 7 and the burner blower fan 52 are stopped and output (S219, S220).

When it is determined in S207 that the light oil is selected, the dotted line side indicating the light oil in the combustion amount-fan rotation speed in FIG. 11 is adopted (S213). Hereinafter, the operation of the combustion burner 7 or the like is executed in the procedure of S209 to S212.

In S204 and S205, the predetermined fuel supply amount and burner fan rotation speed are adopted regardless of the difference in fuel type, but different initial fuel supply amount and initial fan rotation speed are set for each kerosene or light oil. You may.

As shown in FIG. 11, by setting the fan rotation speed of light oil slightly higher than the fan rotation speed of kerosene at the same combustion amount, that is, the fuel supply amount, it is possible to prevent a shortage of primary air and perform stable combustion. ..

As described above, in the present embodiment, the kerosene / light oil selection switch 46 is used as the fuel type output means for outputting to the control unit S whether kerosene is selected as the fuel to be used or light oil is selected. It may be configured by an identification sensor that identifies kerosene and light oil. The identification sensor may be configured to include a color identification means capable of recognizing the colors of colorless and transparent kerosene and light yellow (or light yellowish green) light oil.

Next, with reference to FIG. 10, a specific example of the supply amount increase / decrease output accompanying the proportional combustion control will be described in relation to the detection output of the hot air temperature Tb. The fuel supply amount F (whether the fuel is kerosene or light oil) is output to the proportional control valve 53 to increase or decrease the fuel amount based on the difference from the detected hot air temperature Tb with respect to the set hot air temperature Tc. That is, when the hot air temperature Tb detected by the hot air temperature detection sensor 43 is low with respect to the set hot air temperature Tc, a fuel increase signal is output, and when it is high, a fuel decrease signal is output. The fuel increase signal or fuel decrease signal is configured to gradually increase or decrease every unit amount q (for example, 0.1 liter / hour) in a unit time t (for example, 1 minute). For example, even if the calculation of + 4q increase from the current fuel supply amount is performed due to the difference ΔTb between the detected hot air temperature Tb and the set hot air temperature Tc, the supply amount does not increase by + 4q at once, but the unit time. The control of increasing the temperature such as 1q, 2 × q, etc. is executed every t. In the case of the decrease output, the supply amount decrease −q and -2 × q are output every unit time t as in the case of the increase side.

When a gun type burner is used as the combustion burner 7, the reaction to fuel increase / decrease is fast, and if the fuel supply amount is increased at once, the hot air temperature rises sharply, which is not preferable in terms of quality because excessive hot air is supplied to the dried agricultural products. .. However, by setting the increase / decrease in the fuel supply amount per unit time as the unit amount and changing it step by step as described above, the quality is not deteriorated.

The control unit S outputs a fuel supply amount change request every unit time t, and when this request signal is output, the control unit S calculates the fuel supply amount from the difference between the set hot air temperature Tc and the detected hot air temperature Tb, and is proportional to the fuel supply amount. The increase / decrease in the supply amount to the control valve 53 is output. As shown in FIG. 10, this request signal is executed in the first half of the unit time t, and the supply amount increase / decrease output is maintained during the unit time t. Further, the control unit S is configured to output a hot air temperature detection request, and when receiving this request signal, receive a detection output from the hot air temperature detection sensor 43 that detects the hot air temperature Tb that is sequentially changed. This hot air temperature detection request is configured to be executed in the latter half of the unit time t, that is, it is possible to grasp the fluctuation state of the hot air temperature Tb immediately after the supply amount is increased or decreased by the change output. It is possible to confirm the temperature rise or fall within t / 2 hours in the latter half of the unit time t, to grasp the situation where the temperature rises or falls excessively or the situation that should be lowered but does not fall, prevents grain damage, and causes an accident such as a fire. It can be prevented before it happens.

In the time chart showing the change characteristic of the hot air temperature Tb in FIG. 10, a threshold value of a predetermined width ± α is provided above and below the set hot air temperature Tc, and when the threshold value falls within this threshold value ± α, the increase / decrease control is suppressed. It is supposed to be.

7 Combustion burner 46 Kerosene / light oil selection switch (fuel type output means)
49 Nozzle 52 Blower fan for burner Fa Standard fuel supply amount MRn Hot air temperature average value (during proportional combustion operation)
Min hot air temperature average value (during intermittent combustion operation)
Fmn minimum fuel supply (kerosene)
F'mn minimum fuel supply (light oil)

Claims (6)

A combustion burner (7) having a hot air chamber (14), an exhaust chamber (8), a burner blower fan (52) for supplying combustion air, and a nozzle (49) for supplying fuel, and the combustion burner ( The far-infrared radiator (16), which faces the combustion surface of 7) and is inside the hot air chamber (14) and irradiates the crop with far infrared rays, and the hot air that has flowed into the exhaust chamber (8) are discharged to the outside of the machine. In a crop dryer equipped with an exhaust fan (10), the combustion burner (7) performs an intermittent combustion operation in which a combustion step and a stop step are alternately performed, and a proportional combustion operation in which the fuel supply amount is variable. It is configured to be practicable so that the intermittent combustion operation is performed in a region equal to or less than a preset standard fuel supply amount (Fa), and the proportional combustion operation is performed in a region exceeding the standard fuel supply amount (Fa). A crop dryer configured to continuously operate the burner blower fan (52) even during the stop step of the intermittent combustion operation. The first aspect of the present invention is a configuration in which the rotation speed of the burner blower fan (52) is changed according to the fuel supply amount during the proportional combustion operation, and is set in a predetermined low rotation speed region during the intermittent combustion operation. The listed crop dryer. The crop dryer according to claim 1 or 2, wherein the burner blower fan (52) is operated in a predetermined high rotation region for a predetermined time after the completion of the drying operation. During the drying operation in which the combustion burner (7) executes the intermittent combustion operation, a pause drying operation for stopping the combustion burner (7) is operably provided, and the blower fan for the burner (7) is provided during the pause drying operation. The crop dryer according to any one of claims 1 to 3, wherein 52) is operated in a low rotation region of a predetermined value or less for a predetermined time. During the drying operation in which the combustion burner (7) executes the proportional combustion, a pause drying operation for stopping the combustion burner (7) is operably provided, and the blower fan (52) for the burner is provided during the pause drying operation. ) Is operated for a predetermined time in a high rotation region of a predetermined value or higher, according to any one of claims 1 to 4. A hot air temperature detection sensor (43) is provided to calculate and display the hot air temperature average value (MRn, MIN), and the hot air temperature average value (MIN) during the intermittent combustion operation is determined by the detection value during the combustion process. The method according to any one of claims 1 to 5, wherein the hot air temperature average value (MRn, MIN) during the proportional combustion operation or the intermittent combustion operation is displayed and output in a common period (Td). Crop dryer.

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