JPH0116472B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for drying leaf tobacco in which the quality of dried leaves is good and the drying time is the shortest in the cyclic bulk drying of leaf tobacco.

[Conventional technology]

Conventionally, in this type of drying method, the leaf weight ratio of the drying material is measured during the drying operation of leaf tobacco, and during the yellowing period in the first half of drying, the leaf weight ratio measurement value is determined based on a predetermined leaf weight ratio for each yellowing rate. Drying is performed by selecting the hot air drying wet bulb temperature and adjusting the drying speed so that the leaf weight ratio standard value is achieved.During the drying period in the latter half of the drying period, the hot air flowing into the drying chamber is adjusted to a predetermined value based on the leaf weight ratio measurement value. A method has been proposed in which drying is performed by setting the wet and dry bulb temperature.

In this proposed method, drying according to the drying schedule table proceeds so that the tobacco leaf weight ratio at each drying step matches the standard value, regardless of the raw material conditions. By preparing and drying according to the instructions,
It becomes possible to have a leaf weight ratio curve for the total drying time in the entire drying process. In other words, if the contents of the drying schedule table are ideally set for the variety and leaf type, leaf tobacco can be dried in the standard time, thereby preventing quality deterioration and thermoeconomic losses due to excessive or insufficient drying time. Can be done.

[Problem that the invention seeks to solve]

In the conventional method described above, drying during the yellowing period is performed by selecting a hot air drying wet bulb temperature so that the measured leaf weight ratio becomes a predetermined leaf weight ratio reference value for each yellowing rate, and then adjusting the drying rate. Since the process is carried out while adjusting the yellowing rate, it is necessary to determine the value of the yellowing rate by observing workers during drying.During the long yellowing period of 50 to 55 hours, workers take turns drying The problem was that the progress of the change had to be continuously monitored, which placed an extremely heavy human burden.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems of the conventional methods and to provide a leaf tobacco drying method that eliminates the need for operators to observe the yellowing rate and enables automatic control. In the cyclic bulk drying of leaf tobacco using a hot air dryer to yellow the leaf tobacco, a standard leaf weight ratio pattern and a standard temperature and humidity pattern are set based on the setting of the yellowing time, and the drying room is Measure the bulb temperature, compare the measured dry bulb temperature with the standard temperature according to the standard temperature pattern, control the dry bulb temperature in the drying chamber so that it becomes the standard temperature, measure the humidity in the drying chamber, and compare the measured dry bulb temperature with the standard temperature according to the standard temperature pattern. The humidity in the drying room is controlled to be the standard humidity compared to the standard humidity according to the standard humidity pattern, and the ratio of leaf weight during the yellowing period to the leaf weight at the start of drying of leaf tobacco is measured, and the measured leaf weight ratio is A leaf tobacco drying method characterized in that the standard humidity pattern is changed so that the standard leaf weight ratio becomes the standard leaf weight ratio by comparing the leaf weight ratio with a standard leaf weight ratio pattern, and the leaf tobacco is yellowed using a hot air dryer. and in the cyclic bulk drying of leaf tobacco in a fixed manner,
Based on the yellowing time and fixation time settings, set the standard leaf weight ratio pattern and standard temperature and humidity pattern for each period, measure the dry bulb temperature in the drying room for each period, and set the measured dry bulb temperature as the standard. The dry bulb temperature of the drying room is controlled to be the standard temperature compared with the standard temperature based on the temperature pattern, the humidity of the drying room is measured, and the measured humidity is compared with the standard humidity based on the standard humidity pattern to determine the standard humidity. The humidity in the drying room is controlled so that the leaf weight ratio to the leaf weight at the start of drying of the leaf tobacco is measured, and the measured leaf weight ratio is compared with the standard leaf weight ratio according to the standard leaf weight ratio pattern to determine the standard leaf weight. The leaf tobacco curing method is characterized in that the standard humidity pattern is changed so that the leaf weight ratio is the same, and when yellowing is completed and the measured leaf weight ratio reaches a predetermined value, the yellowing period shifts to the fixed period. It is done by hand.

[Effect]

The moisture content of leaf tobacco that decreases during drying is calculated at any time, and a standard leaf weight ratio pattern, standard temperature and humidity pattern is calculated in advance from the yellowing time and fixed time according to the quality of the leaf tobacco, and leaf weight is calculated based on this. Since the temperature and humidity in the drying chamber are automatically controlled to follow the ratio changes, operators observe the yellowing rate of leaf tobacco during the yellowing period and set the wet-dry bulb temperature difference each time. This tedious work has become unnecessary.

〔Example〕

An example of the drying method of the present invention will be described below.

First, a method of measuring the leaf weight ratio of leaf tobacco during drying operation will be explained.

Now, if the leaf weight ratio is Wc (%), it is expressed as Wc = 100 x (Lw - Mt)/Lw. Here, Lw is the hanging amount (Kg) of leaf tobacco, and can be determined by weighing it at the time of hanging. Mt is the cumulative dehydration amount (Kg),
By integrating the dehydration amount (Kg) per hour M, it is determined by Mt=M ₁ +M ₂ +...+Mn.

The amount of dehydration per hour M can be calculated as M=V×Xd, where V is the ventilation amount per hour (Kg), Xd is the absolute humidity difference (Kg/Kg), and 1
It is calculated from the average value over time, which is determined by the difference between the exhaust absolute humidity (Kg/Kg) This is the average value for one hour calculated using the formula.

X=A+Bd+Cd ² +Ed ³ (0 to 20℃) X=F+ ^{Gd+Hd 2 + Id 3 (} 20 to 40℃) ).

Further, the ventilation amount V per hour is expressed by the following formula.

V=(Vn×Fr+Vf×(1-Fr)×G Here, Vn is 1 determined by the carbon dioxide decay method.
Ventilation volume during fan-on (m ³ / hour), which is a time value;
Fr is the intake fan operation rate calculated by counting the intake fan on time every hour, Vf is the ventilation volume when the fan is off (m ³ / hour), which is an hourly value calculated using the same method as Vn, and G is the specific gravity of air (Kg/m ³ ), which is a constant of 1.14.

Next, a standard leaf weight ratio pattern and a standard temperature and humidity pattern will be explained, and these have been determined empirically based on many years of experience in leaf tobacco drying.

First, the curve formula for the leaf weight ratio W (%) from hanging of leaf tobacco to completion of yellowing is given by W=N+OT ₁ +PT ₁ ² +QT ₁ ³ , where N to Q are constants, and T ₁ is the yellowing time correction value and is expressed as T ₁ =T×(48/Yp). In addition, T is the elapsed time of the yellowing period,
Yp is a set yellowing time, which is preset according to the quality of leaf tobacco.

The completion of yellowing is obtained by the logical product of the yellowing rate of 100 and the leaf weight ratio of 63%, after which the process for mesophyll fixation proceeds.

Next, the curve formula for the leaf weight ratio W (%) from the completion of yellowing to the dry fixation of mesophyll is given by W = R + ST ₂ + TT ₂ ² + UT ₂ ³ , where R ~ U are constants, T ₂ is a fixed time correction value and is expressed as T ₂ =t×(36/Dp). Note that t is the elapsed time of the fixed period,
Dp is a set fixed time, which is preset according to the quality of leaf tobacco.

Mesophyll drying is completed when a leaf weight ratio of 30% is detected, and accordingly, the next step is to dry the mesophyll.

The standard temperature and humidity pattern is set as follows.

The dry bulb temperature at the initial temperature increase was raised from 30℃ to 38℃ over 4 hours, and the heating rate was 8℃/4 hours = 2.0
°C/hour. 38℃ to 43℃ in the next yellowing period
The temperature rises over 44 hours, and the temperature increase rate is 5/44 = 0.1136
℃/hour, during the fixed period, the temperature rises from 43℃ to 50℃ over 36 hours, the temperature increase rate is 7/36 = 0.1944℃/hour,
During the bone drying period, the temperature rises from 50℃ to 68℃ over 18 hours, at a temperature increase rate of 18/18 = 1℃/hour, and after that, the temperature remains constant at 68℃, which usually takes 10 to 20 hours to dry and dry the bone. shall be.

Note that the temperature increase rates for the yellowing period and the fixing period are set according to the yellowing time and fixing time set at the time of hanging depending on the leaf quality, etc., and therefore may differ from the above values.

As a general rule, the dew point remains constant at 35℃ throughout the period.
The calculated leaf weight ratio and standard leaf weight ratio are compared every hour, and if a deviation of 2% or more occurs, the temperature will be increased or decreased by 1°C.

To summarize the above, the standard leaf weight ratio pattern is
The standard temperature and humidity patterns are shown in Figure A and Figure 1B, respectively, and Pattern I is when the yellowing period is set to 48, 36, and 60 hours, and the fixed period is set to 36, 30, and 42 hours, respectively. , I is used as the basic pattern.

Next, a drying apparatus operated according to the leaf tobacco drying method of the above embodiment will be explained with reference to FIG.

In the figure, 10 is a drying chamber, and the drying chamber 1
At 0, there is a heater 1 that performs heating with a burner 11.
2 is introduced as inflow hot air 16 by the circulation fan 14, and in the drying chamber 10, evaporated moisture from the leaf tobacco 18 is obtained and is discharged as outflow hot air 20. It is discharged as exhaust gas 24. Correspondingly, outside air having a lower temperature and lower humidity than the exhaust air 24 flows in through the intake hole 28 as the intake air 26 to perform ventilation. As a result, water vapor corresponding to evaporated water is discharged to the outside air. An air intake fan 30 is attached to the air intake hole 28, and a damper 32 is provided that closes the air intake hole 28 except when the fan is in operation.

Inside the drying chamber 10, a dry bulb temperature control sensor 34 and a dew point control sensor 36 are installed at the inlet of the hot air 16.
However, an exhaust dew point sensor 38 is provided at the outlet of the hot air 20, and an inlet dew point sensor 40 is provided at the inlet hole 28. Drying room 10
Also provided within the leaf color sensor 42 is a leaf color sensor 42 that detects 100% yellowing.

50 is an automatic drying controller having a keyboard 52, a display device 54, and a central processing unit (CPU) 56; The burner controller 60 receives a signal from the air dew point sensor 40 and a signal from the leaf color sensor 42 via the leaf color sensor converter 44 and performs work according to a predetermined program as shown in the flowchart described below. The burner 11 is controlled to be turned on and off, the output of the inverter 62 is automatically varied to control the circulation fan, and the air intake fan 30 and the damper 32 are controlled to be turned on and off by the air intake fan and damper controller 64.

Keyboard 52 included in automatic drying controller 50
is used when inputting the hanging amount (Kg), yellowing time, fixing time, intake fan-on ventilation volume (m ³ ), and intake fan-off ventilation volume according to the message displayed on the display 54. It has a numeric keypad for numeric keypad operations, a return key for inputting numeric keypad data into memory, and a clear key for resetting erroneous inputs on the numeric keypad.
In addition to the above-mentioned message at the time of input, the display 54 displays
Displays set temperature, dew point, measured temperature, dew point, elapsed time, standard leaf weight ratio, calculated leaf weight ratio, yellowing or fixed elapsed time, etc.

The CPU 56 controls the dew point for control by the dry bulb temperature sensor 36 for control by the sensor 34 every 1 to 2 seconds.
The exhaust dew point measured by the sensor 38 and the inlet dew point measured by the sensor 40 are each input as data every minute, and the integrated value for one hour obtained by counting the fan ON time is inputted. Based on these inputs, the CPU 56 performs burner control, intake fan control, and circulation fan control. In burner control, the burner is controlled on and off according to a dedicated temperature pattern, in intake fan control the temperature is automatically set by comparing the measured leaf weight ratio with the standard leaf weight ratio pattern, and in circulation fan control, Automatically varies the inverter output based on the temperature pattern, operating at 80% when it reaches 50℃ and 60% when it reaches 68℃.

In addition to the above, the automatic drying controller 50 is equipped with a printer, which displays the dry bulb temperature, set and measured values of dew point, fan operating rate, absolute input and exhaust temperature, absolute humidity difference, and dehydration every hour. You can also print out the amount, leaf weight ratio, inverter output, elapsed time, etc.

In the above-described configuration, the CPU 56 performs work according to the flowchart shown in FIG. 3 to carry out the leaf tobacco drying method according to the present invention.

The flowchart starts, for example, when the power of the device is turned on, and in the first step S1, the amount of leaf tobacco to be hung is input from the keyboard 52, and then in step S2, the yellowing period time is determined according to the quality of the leaf tobacco. input is received through the same keyboard 52. Based on the input data received in step S2, the CPU 56 calculates a standard temperature and humidity pattern and a standard leaf weight ratio pattern during the yellowing period based on predetermined calculation formulas in subsequent steps S3 and S4. After the calculation in step S4 is completed, the input of the time of the fixed period is received in step S5, and the standard temperature and humidity pattern and the standard leaf weight of the fixed period are calculated in steps S6 and S7 based on a predetermined calculation formula using the input data. Calculate each ratio pattern.

After completing the calculation of the above pattern, step S8
Drying is started in step S9, and the drying time and yellowing time are counted in the next step S9. Then, the process proceeds to step S10, where the sensor 34
and 36 to measure the dry bulb temperature and dew point, respectively. The measured dry bulb temperature is compared with the temperature pattern calculated in step S3 in the next step S11, and if the measured dry bulb temperature is low as a result of the comparison, the burner 11 is turned on by the burner controller 64 in step S12. After that, if the measured dry bulb temperature is high, the burner controller 60 turns off the burner 11 in step S13, and then
And if both are equal, proceed to the next step S14.
Proceed to.

In step S14, the dew point measured in step S10 is compared with the humidity pattern calculated in step S3, and if the measured dew point is low as a result of the comparison, the air intake fan 30 is turned off in step S15, and then the measured dew point is high. After turning on the intake fan in step S16 and counting the operation time of the intake fan in step S17, if the two are equal, the process directly advances to the next step S18. In step S18, the data set and measured in the previous steps are displayed on the display 54.

After that, in the next step S19, it is determined whether the count of the one-minute timer has reached one minute or more, and if it is less than one minute, the process returns to step S10,
The step is that the 1 minute timer has reached 1 minute or more.
Steps S10 to S19 until the determination is made in S19.
is executed repeatedly. Then, when it is determined in step S19 that the one-minute timer has counted one minute or more, the process advances to the next step S20.

In step S20, the sensors 40 and 38 read and integrate the intake dew point and exhaust dew point, respectively, and the process proceeds to the next step S21. In step S21
Determine whether the 60 minute timer has reached 60 minutes or more, and if it is less than 60 minutes, return to step S10 above,
The step is that the 60 minute timer has reached 60 minutes or more.
Steps S10 to S21 until determined by S21
is executed repeatedly. Then, when it is determined in step S21 that the count of the 60 minute timer has reached 60 minutes or more, the process advances to the next step S22.

In step S22, the absolute humidity is calculated using a predetermined formula from the average dew point based on the data read in step S20, and the absolute humidity difference is determined.
The absolute humidity difference determined in step S22 is used to calculate the amount of dehydration and determine the leaf weight ratio in the next step S23. In step S24, it is determined whether or not it is the middle bone drying period. If NO, proceed to step S25; if YES, proceed to step S25.
Proceed to S36. The leaf weight ratio determined in step S23 is compared with a standard leaf weight ratio pattern in the next step S25.

As a result of the comparison in step S25, the step
If the leaf weight ratio calculated in S23 is 2% or more lower than the standard leaf weight ratio pattern, the dew point is raised by 1°C in step S26 (however, the maximum is 36°C), and then the calculated leaf weight ratio is lower than the standard leaf weight ratio pattern. If the gravity ratio is higher than 2%, the dew point is lowered by 1°C in step S27 (at least 34°C), and then set in step S25.
If the result of the comparison in step S28 is that they are equal, the process immediately proceeds to step S28. In step S28, the leaf color sensor 42 detects the color of the leaf tobacco, and the process proceeds to the next step S29. In step S29,
Indicator 54 shows input/exhaust dew point, leaf weight ratio, set dew point, etc.
to be displayed.

After that, in step S30, step S28
As a result of the measurement, it is determined whether yellowing has been completed and the leaf weight ratio is 63% or less. If the determination result is NO, the process returns to step S10, and the above steps are repeated until the determination becomes YES. Repeat steps S10 to S30. Then, the judgment in step S30 is
If YES, the drying during the yellowing period is completed and the process proceeds to the next step S31.

From step S31, a fixed period begins, and thereafter, in steps S11 and S25, the patterns to be compared are changed to those calculated for the fixed period. Then, in the next step S32, the time of the fixed period is counted, and the process proceeds to step S33, where it is determined whether the leaf weight ratio has become 30% or less, and the determination is made.
If NO, the process returns to step S10, and thereafter steps S10 to S33 are repeatedly executed until the determination becomes YES. If the determination in step S33 is YES,
The fixed period of drying is completed and the process proceeds to the next step S34.

From step S34, the bone drying period begins, and from this point on, the temperature pattern used in step S11 is switched to that of the bone drying period, and
The leaf weight ratio pattern used in S25 is eliminated, and the dew point is constant at 35°C. In the next step S35, it is determined whether the set temperature has reached 50°C. If it has not reached it, the set temperature is set to 68°C in the following step S36.
Determine whether it has been reached. If the determination in step S36 is NO, then in step S37 it is determined whether or not the operation rate of the intake fan 30 has become 0. If NO, the process returns to step S10, and thereafter the determination in step S37 is Repeat steps S10 to S37 until YES.

Note that while repeatedly executing steps S10 to S37, if the determination in step S35 is YES, the process advances to step S38, where the inverter 62 is commanded to operate at 80%, and the inverter 62 is commanded to operate at 80%. If the determination is YES, the process advances to step S39, where the inverter 62 is commanded to operate at 60%.
This automatically increases the circulation air volume during the drying period to 80%.
% and 60%, which is effective in preventing deterioration of flavor.

If the determination in step S37 above becomes YES and the operation rate of the intake fan 30 becomes 0, the next step is
Proceed to S40, where it is determined whether the dew point has fallen below 30°C. Then, repeat steps S10 to S40 until the dew point becomes 30℃ or less, and then
When the following conditions are reached, proceed to the next step S40, where the intake fan 30 and burner 11 are stopped.
After a sustained period of time, all steps for tobacco drying are completed.

〔effect〕

As explained above, according to the leaf tobacco drying method according to the present invention, the moisture content of the leaf tobacco that decreases during drying is calculated at any time, yellowing is determined according to the quality of the leaf tobacco that has been inputted in advance, and the special purpose is calculated from the fixed time. A leaf weight ratio pattern and a standard temperature and humidity pattern are set, and the temperature and humidity inside the drying chamber are automatically controlled to follow changes in leaf weight ratio based on these patterns.

Therefore, it is no longer necessary to observe the yellowing rate of the leaf tobacco during drying and set the wet and dry bulb temperature every time a predetermined yellowing rate is reached, as was the case in the past, and drying automatically progresses until the end of yellowing. In particular, if the end of yellowing is detected using a leaf color sensor, it will be possible to automatically move to the next fixed period, greatly reducing the burden on the operator. be done.

[Brief explanation of drawings]

FIG. 1 is a graph for explaining an example of the leaf tobacco drying method according to the present invention, in which a shows a standard leaf weight ratio pattern, b shows a standard temperature and humidity pattern, and FIG. A diagram showing an example of the operating drying apparatus, and FIG. 3 is the same as in FIG.
FIG. 3 is a flowchart showing the work performed by the CPU. Figure 1a...Standard leaf weight ratio pattern, Figure 1b...
...Standard temperature and humidity pattern, 10...Drying room, 12...
... Heater, 14 ... Circulation fan, 18 ... Leaf tobacco, 34 ... Sensor for dry bulb temperature control, 36 ... Sensor for dew point control, 38 ... Dew point sensor for exhaust air, 4
0...Inlet air dew point sensor, 50...Automatic drying controller.

Claims (1)

[Claims] 1. In the cyclic bulk drying of leaf tobacco in which the leaf tobacco is yellowed using a hot air dryer, a standard leaf weight ratio pattern and a standard temperature and humidity pattern are respectively set based on the setting of the yellowing time. The dry bulb temperature of the drying chamber is controlled so that it becomes the standard temperature by comparing the measured dry bulb temperature with the standard temperature according to the standard temperature pattern, and the humidity of the drying chamber is controlled. The measured humidity is compared with the standard humidity according to the standard temperature and humidity pattern, and the humidity in the drying room is controlled so that the humidity becomes the standard humidity, and the ratio of leaf weight during the yellowing period to the leaf weight at the start of drying of leaf tobacco is calculated. A leaf tobacco drying method comprising measuring the measured leaf weight ratio, comparing the measured leaf weight ratio with a standard leaf weight ratio based on a standard leaf weight ratio pattern, and changing the standard humidity pattern so that the leaf weight ratio becomes the standard leaf weight ratio. 2. In the cyclic bulk drying of leaf tobacco in which leaf tobacco is yellowed and fixed using a hot air dryer, the standard leaf weight ratio pattern and standard temperature and humidity pattern for each period are determined based on the settings of the yellowing time and fixation time. The dry bulb temperature of the drying chamber is controlled so that it becomes the standard temperature by comparing the measured dry bulb temperature with the standard temperature according to the standard temperature pattern, and drying. The humidity in the drying room is measured, the measured humidity is compared with the standard humidity according to the standard humidity pattern, the humidity in the drying room is controlled to be the standard humidity, and the ratio of leaf weight to leaf weight at the start of drying of leaf tobacco is measured. , the measured leaf weight ratio is compared with the standard leaf weight ratio according to the standard leaf weight ratio pattern, and the standard humidity pattern is changed so that the leaf weight ratio becomes the standard leaf weight ratio, and yellowing is completed and the measured leaf weight ratio is a predetermined value. A leaf tobacco drying method characterized by a transition from a yellowing period to a fixed period as the value reaches a certain value.