JPS6159113B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a leaf tobacco drying device used for drying leaf tobacco in the tobacco manufacturing process. This invention relates to an improved device that adjusts and controls the humidity in a drying chamber depending on the leaf weight ratio.

Regarding the drying process of leaf tobacco, the fermentation period, yellowing period,
There are four processing stages: the color selection fixation stage and the bone drying stage, and each stage differs depending on the variety, crop, and harvest time. The leaf weight ratio that decreases through each stage of processing is known.

Conventional or already proposed drying devices include:
The temperature and humidity of the drying treatment chamber are detected, and the heater and the moisture removal means are controlled manually or automatically, thereby indirectly obtaining a leaf weight ratio suitable for each of the drying treatment progress stages. However, since it does not directly measure leaf weight, it is difficult to obtain an accurate leaf weight ratio, and since it uses a psychrometric bulb hygrometer to measure humidity, it is difficult to obtain an accurate leaf weight ratio. The wet bulb thermometer becomes dirty with dust, etc., which obstructs accurate humidity measurement, and at the same time, there are problems in that complicated cleaning work must be performed frequently.

The purpose of the present invention is to solve the above-mentioned difficulties and problems, directly measure the leaf weight of leaf tobacco in the drying chamber, and dry the leaf tobacco at the ideal temperature and leaf weight ratio at each processing stage. The purpose is to provide equipment.

Another object of the present invention is to temporarily stop the operation of the heater and the blower when measuring leaf weight;
To provide a leaf tobacco drying device capable of accurately measuring leaf weight by stopping the circulation of drying hot air that shakes leaf tobacco.

In order to achieve these objectives, the present invention provides a set of reference temperature data representing the temperature of the processing chamber to be ensured for each stage of the tobacco curing process, and a set of reference temperature data to be set for each progressive stage as well. a memory that stores leaf weight ratio data at each address; an addressing circuit that outputs address signals in response to clock pulses from a clock pulse generator and sequentially designates addresses in the memory; a heater operation signal generating means for outputting a heater operation signal such that a deviation signal between a reference temperature signal read out sequentially and a temperature signal from the temperature sensor becomes zero; a heater adjustment means for adjusting the calorific value of the tobacco sample; a leaf weight sensor installed in the processing chamber for measuring the leaf weight of the leaf tobacco sample; a leaf weight ratio signal generating means that calculates a leaf weight ratio with respect to the leaf weight ratio; a reference leaf weight ratio signal that is sequentially read out from a memory in response to an address signal; and a leaf weight ratio signal from the leaf weight ratio signal generating means. a dehumidifying means operation signal generating means that outputs a dehumidifying means operation signal such that the deviation signal of the dehumidifying means becomes zero; It stops the operation of the heater and air blower for a certain period of time at predetermined time intervals, and sends a humidity removal means operation signal to the humidification means, and at other times, the humidification means stops operating. The apparatus is characterized in that it is provided with a dehumidification adjustment time designation means for cutting off the operation signal.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a graph showing an example of an ideal leaf weight ratio curve for forming a reference leaf weight ratio signal in the present invention. The horizontal axis represents the progress of each treatment stage in terms of time, and the vertical axis represents the degree of dryness relative to the initial leaf weight set before drying treatment in terms of leaf weight ratio. By operating the moisture removal means and advancing each stage of the drying process, the taste, flavor and aroma of leaf tobacco can be fully expressed.

FIG. 2 is a graph showing an example of an ideal temperature curve for forming a reference temperature signal in the present invention. The horizontal axis represents the progress of each processing stage in time, as in Figure 1, and the vertical axis represents the temperature of the processing chamber.
The heater control device is operated so as to follow the ideal temperature curve 2, and settings are made to advance each stage of the drying process.

FIG. 3 shows a leaf tobacco drying apparatus which is an embodiment of the present invention. Leaf tobacco 3 is held by a holder 4 in a processing chamber 6 surrounded by a heat insulating wall 5. A sample 3' of leaf tobacco of the same variety, same crop pattern, and same harvest time as leaf tobacco 3 was suspended in the processing chamber 6.
It is held in a holder 8 so that the leaf weight can be measured by the leaf weight sensor 7. The leaf weight sensor 7 and the temperature sensor 9, which is also disposed inside the processing chamber 6, are connected to the controller 1 outside the processing chamber 6 by signal lines 10 and 11, respectively.
Connected to 2. The heater 13, the blower 14, and the dehumidifying actuator 15 operated by hydraulic pressure are each arranged outside the processing chamber 6 so as to be controlled by the controller 12. The air heated by the heater 13 is blown into the processing chamber 16 from the blowhole 17 of the duct 16 by the blower 14, and is passed from the processing chamber 6 to the heater 13 while drying the leaf tobacco 3 and the sample 3'. It is circulated by a rolling circulation duct 18. At this time, the hot air circulating through the processing chamber 6, the circulation duct 18, the heater 13, the blower 14, and the duct 16 is controlled by the controller 1 based on the signal from the temperature sensor 7.
The water contained in the leaf tobacco 3 and the sample 3' is evaporated by the heater 13 controlled by the command signal 2 at a temperature set according to the ideal temperature curve 2 shown in FIG. Sample 3' is dried, ie its leaf weight is reduced. At the same time, the above-mentioned reflux becomes highly humid in response to the reduction in leaf weight. Changes in leaf weight of sample 3', which is in the same dry state as leaf tobacco 3, are detected by leaf weight sensor 7 as a leaf weight signal on signal line 1.
0 to the controller 12, and the controller 12 outputs an operation signal for the humidity removal actuator 15 according to the difference between the reference leaf weight ratio signal and the leaf weight signal, and the humidity removal actuator 15 is operated by the drive rod 19. The opening degree of the dehumidification vane 21 and the intake vane 22 to be operated via the operation rod 20 is set. As a result, a predetermined amount of water vapor contained in the reflux is discharged to the outside from the moisture removal vane 21 through the moisture outlet 23, and the ideal leaf weight ratio curve 1 shown in FIG. 1 is set. The humidity in the processing chamber 6 is adjusted and maintained in accordance with each stage of the drying process. The same amount of air as the amount of removed moisture is sucked into the circulation duct 18 by the suction vane 22 and replenished during the reflux. Note that since the controller 12 outputs an instruction signal to stop the heater 13 and the blower 14 for a certain period of time at predetermined time intervals, the leaf weight sensor 7
is not shaken by the circulation of hot air,
It is possible to accurately measure the leaf weight of sample 3'.

FIG. 4 is a perspective view showing one embodiment of a leaf weight sensor forming a part of the present invention. A leaf tobacco sample 3' selected for leaf weight measurement is held by a holder 8 and attached to a measuring rod 26 by a wire 25.
suspended from the The leaf weight applied to the measuring rod 26 is displayed on the weight scale 27 of the leaf weight sensor 7, and at the same time, a leaf weight signal indicating the drying state of the sample 3', that is, the leaf tobacco 3 at each drying stage, is transmitted via the signal line 10. It is transmitted to the controller 12 as a. 28 is a guard member formed of wire or the like, and 29 is a dial for adjusting the measurement reference point. FIG. 5 is a perspective view showing another embodiment of the leaf weight sensor 7 forming a part of the present invention. The same parts as in FIG. 4 are designated by the same reference numerals. Measuring table 3 installed on leaf weight sensor 7
A basket 31 is installed at 0, and a sample 3' held by a holder 8 is accommodated therein so that it can be measured. Fourth
Similarly to the illustrated embodiment, the leaf weight of the sample 3' measured by the leaf weight sensor 7 is expressed as a leaf weight signal.
It is transmitted to the controller 12 via a signal line 10.

In both the embodiments shown in FIGS. 4 and 5, the drying of the sample 3' and the leaf weight measurement at each drying process stage are directly and automatically performed, and the humidity within the processing chamber 6 is accurately controlled. A leaf weight ratio can be obtained.

FIG. 6 is a block diagram showing the configuration of the controller 12 in FIG. 3. FIG. 6 will be described below with reference to FIGS. 1 to 5. EP-ROM
A control circuit 33 and an address designation circuit 3 are connected to the control terminal and address terminal of the reference temperature memory 32 consisting of
4 is connected, and a control circuit 33 and an address designation circuit 34 are connected to the control terminal and address terminal of a reference leaf weight ratio memory 35, which also consists of an EP-ROM or the like.

The input terminal of the control circuit 33 is connected to a clock pulse generator 36, and the output terminal thereof is connected to an addressing circuit 34. Addressing circuit 3
The output terminal of No. 4 is connected to a display 38 via a decoder driver 37.

The output terminal of the reference temperature memory 32 is connected to one input terminal of an operational amplifier 40a via a digital-to-analog converter 39, and further connected to one input terminal of the operational amplifier 40a.
A proportional controller 40b is connected to the output terminal 0a.

The operational amplifier 40a and the proportional controller 40b constitute a heater operation signal generation section 40.

Output terminal 40c of heater operation signal generation section 40
is connected to a heater control device 42 that adjusts and controls the heater 13 via a gate circuit 41, and an input terminal 40d of the heater operation signal generation section 40, that is, another input terminal of the operational amplifier 40a, is connected to a signal line 1
Temperature sensor 9 disposed in processing chamber 6 through 1
connected to.

An output terminal of the reference leaf weight ratio memory 35 is connected to one input terminal of an operational amplifier 44a via a digital-to-analog converter 43, and a proportional controller 44b is further connected to the output terminal of the operational amplifier 44a. .

The operational amplifier 44a and the proportional controller 44b constitute a dehumidification means operation signal generation section 44.

Output terminal 44c of the moisture removal means operation signal generation section 44
is a dehumidification actuator control device 46 which opens and closes the dehumidification vane 21 and the suction vane 22 which dehumidify the water vapor circulating in the processing chamber 6 and the circulation duct 18 and take in supplementary outside air via the gate circuit 45;
Another input terminal 44d of the dehumidification means operation signal generation section 44 is connected to an output terminal of an operational amplifier 47 that calculates the measured value of the leaf weight sensor 7 as a leaf weight ratio to the initial leaf weight. amplifier 47
The input terminal of is connected to a leaf weight sensor 7 disposed within the processing chamber 6 through a signal line 10.

The time-division signal generator 48 generates a signal every 30 minutes or once every 30 minutes, for example.
A time-division signal with a constant time width is output at predetermined time intervals, and the gate circuit 45 is controlled to open by this time-division signal. Further, the gate circuit 41 and the blower on/off controller 49 are
When the time division signal whose sign is inverted by the inverter 50 is input, the blower is closed or the blower is turned off, and at other times, the blower is opened or turned on.

Note that 51 is an operating device connected to the control circuit 33, and 52 is a timer for extending time interposed between the operating device 51 and the control circuit 33.

In the above configuration, the reference temperature memory 32 includes:
For example, a group of reference temperature data corresponding to temperature curve 2 shown in FIG. 2 is stored in a series of addresses to form one storage area.

Furthermore, although not shown in FIG. 2, there is another temperature curve that is selectively adopted depending on the type of leaf, and another group of reference temperature data corresponding to this curve forms the above-mentioned one storage area. are stored in another series of addresses corresponding to each series of addresses to form another storage area.

On the other hand, in the reference leaf weight ratio memory 35, for example, the first
A reference leaf weight ratio data group corresponding to leaf weight ratio curve 1 shown in the figure is stored in a series of addresses to form one storage area.

Furthermore, although not shown in Figure 1, there is another leaf weight ratio curve that is selectively adopted depending on the type of leaf, and another standard leaf weight ratio data group corresponding to this curve is different from the above one. Each of the series of addresses forming a storage area is stored in another series of addresses corresponding to each other to form another storage area.

Thereafter, in the same manner, a plurality of reference temperature data groups and a plurality of reference leaf weight ratio data groups selected according to the leaf type are respectively formed in the reference temperature memory 32 and the reference leaf weight ratio memory 35. It is stored in multiple storage areas.

Now, when the operator operates the operating device 51 consisting of a digital switch or the like and gives the control circuit 33 a digital code for specifying the temperature curve and leaf weight ratio curve according to the type of leaf, the control circuit 33 In order to specify the upper digits of the address signals supplied to the address terminals of the reference temperature memory 32 and the reference leaf weight ratio memory 35 in accordance with the digital code, and read the data from the reference temperature memory 32 and the reference leaf weight ratio memory 35. Select storage area.

When the drying process is started, the control circuit 33 first sends a control signal to the control terminals of the reference temperature memory 32 and the reference leaf weight ratio memory 35 to switch them to the read mode.

Control circuit 33 then transfers the clock pulses supplied from clock pulse generator 36 to addressing circuit 34. Addressing circuit 34
counts clock pulses and advances, and supplies the lower digits of the address signal to the address terminals of the reference temperature memory 32 and the reference leaf weight ratio memory 35.

Therefore, the reference temperature memory 33 and the reference leaf weight ratio memory 35 read out the data specified by the lower digits of the address signal within the storage area specified by the upper digits of the address signal. is a series of reference temperature data corresponding to one selected temperature curve, and similarly, from the reference leaf weight ratio memory 35, a series of reference leaf weight ratio data is sent to the step of the addressing circuit 34. They are read out sequentially and sent to the digital-to-analog converter 3.
9 and 43, respectively.

The digital-to-analog converter 39 converts a series of sequentially supplied reference temperature data into an analog voltage, and uses this as a reference temperature signal to the operational amplifier 40a.
one input terminal of the Operational amplifier 40a
calculates the difference between this reference temperature signal and the temperature signal supplied from the temperature sensor 9 to the other input terminal, and supplies a deviation signal to the proportional controller 40b.

The proportional controller 40b supplies a heater operation signal with an amplitude proportional to the deviation signal from the output terminal 40c via the gate circuit 41 to the heater control device 42, and automatically controls the amount of heat generated by the heater 13. At this time, the gate circuit 41 is opened by the high-level signal output from the inverter 50, and at the same time, the blower 14 is also activated by the ON operation of the blower on/off controller 49, and the hot air flows through the duct 16 and the blowhole. 17 and is recycled from the processing chamber 6 to the circulation duct 18.

In such additional value control, the heat generation amount of the heater 13 is controlled so that the temperature signal of the temperature sensor 9 matches the reference temperature signal and the deviation signal becomes zero, so the temperature in the processing chamber 6 is set in advance. According to the reference temperature data stored in the reference temperature memory 32, the temperature is maintained at a suitable value at each stage of the drying process.

On the other hand, the digital-to-analog converter 43 converts a series of sequentially supplied reference leaf weight ratio data into an analog voltage, and supplies this as a reference leaf weight ratio signal to one input terminal of the operational amplifier 44a.

The operational amplifier 47 calculates the leaf weight signal of the leaf tobacco sample 3' supplied from the leaf weight sensor 7 as a leaf weight ratio to the initial leaf weight before the drying process, and uses this as the leaf weight ratio signal to operate the humidifier. Signal generation section 44
is supplied to one input terminal 44d of an operational amplifier 44a.

The operational amplifier 44a receives a reference leaf weight ratio signal at one input terminal, and a leaf weight ratio signal from an operational amplifier 47 that calculates the leaf weight ratio value from the leaf weight signal of the leaf weight sensor 7 at another input terminal. In response, the difference between both signals is calculated and the deviation signal is supplied to the proportional controller 44b.

The proportional controller 44b outputs a dehumidification means operation signal having an amplitude proportional to the deviation signal, and this signal is
The signal is supplied to the dehumidification actuator control device 46 via the gate circuit 45 which is opened at predetermined time intervals according to the time division signal from the time division signal generator 48, and the dehumidification vane 21 and the intake vane 22 are activated at predetermined time intervals. automatically controlled. When the gate circuit 45 is closed, the moisture removal actuator 15 maintains its position.

In such follow-up control, the opening degrees of the drainage vane 21 and the intake vane 22 are controlled so that the leaf weight ratio signal from the sample 3' matches the reference leaf weight ratio signal and the deviation signal becomes zero. The humidity in the processing chamber 6 is adjusted to maintain a suitable leaf weight ratio value at each stage of the drying process according to the reference leaf weight ratio data stored in the reference leaf weight ratio memory 35 in advance. Ru.

The heater operation signal and the dehumidification means operation signal described above are generated by gate circuits 41 and 45 interposed between the respective signal generation means 40 and 44 and the heater control device 42 and the dehumidification actuator control device 46. The signal is controlled by the time division signal generator 48 that supplies the signals so that they are not transmitted simultaneously, and the heater 13 and the blower 14 are stopped for a certain period of time at every predetermined time interval, and within the stopping time , the leaf weight is measured by the leaf weight sensor 7, the moisture removal vane 21 and the intake vane 22 are operated to adjust the humidity corresponding to the leaf weight ratio, and the heater 1
3 and the blower 14, the opening degree of both vanes 21 and 22 is maintained according to the given dehumidifying means operation signal, so that the sample can be removed without being hindered by the circulation of hot air by the blower 14. Not only can the 3' leaf weight be measured directly, but also each stage of the drying process can be carried out by adjusting the ideal temperature and humidity according to the type of leaf tobacco.

While the above automatic control is performed and the drying process is in progress, the addressing circuit 3
4 steps forward and sequentially specifies the data to be read from the reference temperature memory 32 and the reference leaf weight ratio memory 35. The decoder driver 37 converts the lower digits of the address signal supplied to the address signal 35 into, for example, an 8-segment display tube drive signal and supplies it to the display 38, thereby indicating the progress stage of the drying process. The displayed information, more specifically, the number of reference temperature data and reference leaf weight ratio data according to which the control is being performed can be displayed.

As long as the clock pulses remain constant, the progression step display will be the same as the elapsed time display of the drying process.

By the way, the reference temperature memory 32 and the reference leaf weight ratio memory 35 are configured to store multiple reference temperature data groups and a plurality of reference leaf weight ratio data groups in a plurality of storage areas in correspondence with the types of leaves. has been,
Although it can be applied to various temperature curves and leaf weight ratio curves, it is difficult to apply it to all deformation curves depending on the individual state of leaves due to the capacity of the reference temperature memory 32 and leaf weight ratio memory 35. becomes huge,
Since this is uneconomical, it is necessary to extend the processing progress stage.

In such a case, the operator operates the operating device 51 such as a digital switch to temporarily store a digital code representing the extension time in the time extension timer 52.

Then, while observing the color, etc. of the leaf tobacco 3 in the processing chamber 6 through the monitoring window 24, at an appropriate processing stage, the controller 51 is operated again to send a time extension command signal to the time extension timer 52. The signal is sent to the control circuit 33.

Upon receiving the time extension command signal, the time extension timer 52 determines the elapse of the extension time represented by the once stored digital code by subtraction counting, etc., and supplies an extension time end signal to the control circuit 33.

Then, the control circuit 33 stops transferring the clock pulse to the addressing circuit 34 and stops its progress from receiving the time extension command signal until receiving the extension time end signal, that is, for the extension time.

Since the lower digits of the address signal are retained as they are, new reference temperature data and reference leaf weight ratio data are not read out, and specific reference data is not read from the reference temperature memory 33 and reference leaf weight ratio memory 35. Temperature data and reference leaf weight ratio data are continuously output, and the processing progress stage remains at the same stage for an extended period of time.

In addition, although the reference temperature memory 33 and the reference leaf weight ratio memory 35 are provided in the above embodiment, these may be different storage areas of the only memory as hardware.

Further, the heater operation signal generation section 40 and the dehumidification means operation signal generation section 44 are connected to proportional controllers 40b and 44b.
However, if necessary, a difference signal between the temperature signal of the temperature sensor 9 and the reference temperature signal, and a difference signal between the leaf weight ratio signal and the reference leaf weight ratio signal of the leaf weight sensor 7 and the operational amplifier 47 are required. It is sufficient that a follow-up control loop is configured such that both deviation signals become zero, and in particular, in place of both or one of the proportional controllers 40b and 44b, the deviation signal exceeds a specific dead amount. In such a case, an on/off controller that outputs a digital signal may be adopted. The number of leaf weight sensors 7 is not limited to one, and a plurality of leaf weight sensors 7 may be arranged at appropriate positions in the processing chamber 6 and their measured values may be averaged.

Further, although the dehumidifying means operation signal is configured to cause the dehumidifying vane 21 and the intake vane 22 to operate in conjunction with each other, the dehumidifying means operating signal may operate only the dehumidifying vane 21.

In addition, although the configuration of the embodiment is a circulation type drying device equipped with a circulation duct 18 as a hot air circulation path, if necessary, a heater 13 is installed to ensure hot air for drying leaf tobacco in the processing chamber 6. The present invention can also be implemented in a so-called direct flame type drying device, as long as it is provided with a moisture removal vane that adjusts the leaf weight by adjusting the amount of water vapor discharged from the processing chamber 6.

In this embodiment, the air blower 14 is used as the air blowing means of the present invention, the dehumidifying actuator 15, the drive rod 19, the operation rod 20, and the dehumidifying vane 21 are used as the dehumidifying means, and the operational amplifier 40a and the proportional controller 40b are used as the dehumidifying means. is the heater operation signal generation means, the heater control device 42 is the heater adjustment means, the operational amplifier 47 is the leaf weight ratio signal generation means, the operational amplifier 44a and the proportional controller 44
b is a dehumidification means operation signal generation means, a time division signal generator 48, gate circuits 41 and 45, and an inverter 5.
0 corresponds to the humidity adjustment time designation means.

Furthermore, if a plurality of storage areas are formed in each memory and a plurality of reference temperature data groups and reference leaf weight ratio data groups corresponding to various temperature curves and leaf weight ratio curves are stored, it is possible to It is possible to easily control the temperature and leaf weight ratio in different patterns depending on the type of leaf.

As explained above, according to the present invention, a series of reference temperature data representing the temperature of the processing chamber to be maintained for each stage of the drying process, and a series of reference temperature data to be set for each stage of the drying process are also provided. A memory that stores reference leaf weight ratio data at each address, an addressing circuit that outputs an address signal in response to a clock pulse from a clock pulse generator and sequentially designates addresses in the memory, and a memory that stores reference leaf weight ratio data in each address. a heater operation signal generating means for outputting a heater operation signal such that a deviation signal between a reference temperature signal read out sequentially and a temperature signal from the temperature sensor becomes zero; A heater adjustment means for adjusting the calorific value of the tobacco, a leaf weight sensor installed in each processing chamber to measure the leaf weight of the leaf tobacco sample, and a leaf weight signal from the leaf weight sensor to be set at an initial value before the drying process. A leaf weight ratio signal generating means that calculates a leaf weight ratio with respect to leaf weight, a reference leaf weight ratio signal that is sequentially read out from a memory in response to an address signal, and a leaf weight ratio signal from the leaf weight ratio signal generating means. a dehumidifying means operation signal generating means that outputs a dehumidifying means operation signal such that the deviation signal between the dehumidifying means and the dehumidifying means becomes zero; The dehumidifying means is maintained during the interval, and the operation of the heater and the air blowing means is stopped for a certain period of time at predetermined time intervals, and a dehumidifying means operation signal is sent to the dehumidifying means, and the dehumidifying device is stopped at other times. Since the device is equipped with a means for specifying the humidity adjustment time to interrupt the means operation signal, the leaf tobacco is not swayed by the hot drying air during leaf weight measurement, and leaf weight can be measured accurately. Each step of the drying process is progressed while controlling the leaf weight ratio detected from the change in leaf weight and the temperature of the processing chamber using the ideal leaf weight ratio data and ideal temperature data in the memory. It is possible,
These allow the taste, flavor and aroma of leaf tobacco to be fully expressed.

[Brief explanation of the drawing]

Figure 1 is a graph showing the leaf weight ratio at each stage of the tobacco drying process, Figure 2 is a graph showing the temperature of the processing chamber at each stage of the drying process, and Figure 3 is an example of the present invention. FIG. 4 is a perspective view showing an embodiment of a leaf weight sensor that constitutes a part of the present invention, and FIG. FIG. 6 is a perspective view showing an embodiment of the heavy sensor, and FIG. 6 is a block diagram showing the configuration of the control device of the present invention. 1... Leaf weight ratio ideal curve, 2... Temperature ideal curve,
3... Leaf tobacco, 3'... Leaf tobacco sample, 6...
...Processing chamber, 7... Leaf weight sensor, 9... Temperature sensor, 13... Heater, 14... Air blower, 15...
Moisture drainage actuator, 21...Drainage vane, 3
2...Reference temperature memory, 34...Address designation circuit, 35...Reference leaf weight ratio memory, 36...Clock pulse generator, 40...Heater operation signal generation section, 41...Gate circuit, 42...Heating device control device, 44... dehumidification means operation signal generation section, 45...
Gate circuit, 47... operational amplifier, 48... time division signal generator, 50... inverter.

Claims (1)

[Claims] 1. A processing chamber in which leaf tobacco is held, a heater and a blowing means for circulating the air heated by the heater into the processing chamber, a dehumidification means for adjusting the humidity of the processing chamber, and a In a leaf tobacco drying apparatus equipped with a temperature sensor, a series of reference temperature data representing the temperature in the processing chamber to be maintained for each stage of the drying process, and a series of reference temperature data to be set for each stage of the drying process. A memory that stores reference leaf weight ratio data at each address, an addressing circuit that outputs an address signal in response to a clock pulse from a clock pulse generator and sequentially designates addresses in the memory, and a memory that stores reference leaf weight ratio data in each address. a heater operation signal generating means for outputting a heater operation signal such that a deviation signal between a reference temperature signal read out sequentially and a temperature signal from the temperature sensor becomes zero; a heater adjustment means for adjusting the calorific value of the tobacco sample; a leaf weight sensor installed in the processing chamber for measuring the leaf weight of the leaf tobacco sample; a leaf weight ratio signal generating means that calculates a leaf weight ratio with respect to the leaf weight ratio; a reference leaf weight ratio signal that is sequentially read out from a memory in response to an address signal; and a leaf weight ratio signal from the leaf weight ratio signal generating means. a dehumidifying means operation signal generating means that outputs a dehumidifying means operation signal such that the deviation signal of the dehumidifying means becomes zero; The operation of the heater and blower is stopped for a certain period of time at predetermined time intervals, and the operation signal of the humidity removal means is sent to the humidity removal means. A leaf tobacco drying device characterized by being provided with a humidity adjustment time designation means for cutting off an operation signal.