WO2013136487A1

WO2013136487A1 - Method for humidifying starting tobacco material

Info

Publication number: WO2013136487A1
Application number: PCT/JP2012/056716
Authority: WO
Inventors: 晃更屋; 忍宮守; 隆司岩井; 伊藤　直樹; 弘明高野
Original assignee: 日本たばこ産業株式会社
Priority date: 2012-03-15
Filing date: 2012-03-15
Publication date: 2013-09-19
Also published as: JP5709289B2; PL2798965T3; EP2798965A4; CN104168782A; CN104168782B; JPWO2013136487A1; EP2798965A1; EP2798965B1

Abstract

Provided is a humidification method which comprises supplying a starting tobacco material and steam into a rotor and humidifying the starting tobacco material during the passage of the starting tobacco material through the rotor. The humidification method involves: a main control step for determining a deviation between the outlet material temperature of the starting tobacco material at the outlet of the rotor and a target temperature and then cascade-controlling the flow rate of the steam to be supplied into the rotor so as to eliminate the deviation, wherein multiple control areas exist in the cascade-control and the supply flow rate is controlled on the basis of a standard flow rate in each of the control areas; and a side control step, said side control step being performed in parallel to the main control step, for changing the standard flow rate on the basis of the average deviation during a definite period.

Description

Humidity control method for tobacco materials

The present invention relates to a humidity control method suitable for tobacco materials such as leaf tobacco.

The processing of leaf tobacco as a tobacco raw material includes a humidity control step for increasing its moisture content. Such a humidity control step is an important step for imparting flexibility to the leaf tobacco when removing the petiole from the leaf tobacco.
A humidity control method for executing the humidity control process described above is disclosed in, for example, Patent Document 1 below. The humidity control method of Patent Document 1 measures the initial moisture content, initial temperature and supply amount of tobacco at the inlet of the humidity controller, and the moisture content and temperature of tobacco after conditioning at the outlet of the humidity controller. Based on the measurement result, the amount of moisture and the amount of steam to be supplied to the tobacco are controlled, and the moisture content and temperature of the tobacco after humidity adjustment are adjusted to target values.

JP-B 63-62185 (JP 1988-62185 B2)

In the humidity control method of Patent Document 1 described above, although the moisture content of the tobacco leaf after humidity control can be adjusted to the target value, it is necessary to measure the moisture content of the tobacco leaf at each of the inlet and outlet of the humidity controller. . For this reason, when the humidity control method of patent document 1 considers the objective which provides a softness | flexibility to leaf tobacco, control of a vapor | steam amount becomes more complicated than necessary.

An object of the present invention is to provide a humidity control method that can easily increase the amount of moisture in a tobacco material so as to impart the necessary flexibility to the tobacco material.

The above object is achieved by the humidity control method for tobacco raw material of the present invention, and the humidity control method of the present invention focuses on the outlet product temperature of the conditioned tobacco raw material and maintains the outlet product temperature at the target temperature. Control steam supply.

Specifically, the present invention provides a humidity control method for supplying tobacco raw material and steam into the rotor and conditioning the tobacco raw material in a process in which the tobacco raw material passes through the rotor.
A step of detecting the outlet product temperature of the tobacco raw material immediately after being discharged from the rotor outlet when steam is supplied into the rotor at a supply flow rate;
Determining a first deviation between the target temperature of the tobacco raw material at the outlet and the outlet product temperature;
A main control step of controlling the supply flow rate of the steam based on the reference flow rate of the steam based on the first deviation,
The main control process is
Select a control area corresponding to the first deviation from a plurality of control areas divided according to the magnitude and positive / negative of the first deviation,
The steam supply flow rate is controlled according to the control procedure in the selected control area.

According to the humidity control method described above, the outlet product temperature of the tobacco material is detected during the humidity control of the tobacco material, and the supply flow rate of steam into the rotor is set to the reference flow rate so that the outlet product temperature matches the target temperature. Controlled based on. Thus, if the outlet product temperature of the tobacco raw material after humidity adjustment is adjusted to the target temperature, the moisture content of the tobacco raw material is easily increased.

Specifically, the main control process is
A dead band that is selected when the first deviation is between a positive first threshold value and a negative second threshold value to maintain the supply flow rate at a reference flow rate;
The supply flow rate is selected according to a corrected flow rate that is selected when the first deviation exceeds the first threshold value and is within a positive third threshold value that is greater than the first threshold value and is calculated based on the cubic function of the first deviation. A positive-order cubic function control range that decreases from the reference flow rate;
Supply flow rate according to a corrected flow rate that is selected when the first deviation exceeds the negative two threshold value and is within a negative fourth threshold value that is greater than the second threshold value and calculated based on the cubic function of the first deviation. And a negative-order cubic function control region that increases the flow rate from the reference flow rate.

If the positive and negative cubic function control areas are included in the control range of the main control process described above, these cubic function control areas will change this against the instantaneous change in outlet product temperature. It works effectively to compensate quickly.

Preferably, the main control step is
Selected when the first deviation exceeds the positive third threshold and is within the positive fifth threshold greater than the third threshold, and supplied according to the corrected flow rate calculated based on the linear function of the first deviation A positive-side linear function control area for reducing the flow rate from the reference flow rate;
According to the corrected flow rate selected when the first deviation exceeds the negative fourth threshold and is within the negative sixth threshold greater than the fourth threshold, and is calculated based on the linear function of the first deviation, And a negative-side linear function control region for increasing the supply flow rate from the reference flow rate.

If the control area of the main control process further includes positive and negative linear function control areas, these linear function control areas increase and decrease the supply flow rate according to the correction flow rate proportional to the first deviation, and supply The outlet product temperature can be quickly returned to the target temperature without changing the flow rate rapidly.

More preferably, the main control step is
A positive fixed control range that is selected when the first deviation exceeds a positive fifth threshold and limits the supply flow rate to a certain lower limit flow rate;
A negative fixed control region that is selected when the first deviation exceeds the negative sixth threshold and limits the supply flow rate to a certain upper limit flow rate,
Such positive and negative fixed control areas prevent excessive increase or decrease in the supply flow rate.

Furthermore, the humidity control method of the present invention can further include a sub-control step executed in parallel with the above-described main control step. This sub-control step includes a reference flow rate reset control area that is periodically repeated, and the reset control area resets the reference flow rate based on the average value of the first deviation over a certain period.
Such feedback control reduces adverse effects on the main control process caused by continuous changes in the outlet product temperature, and makes the control of the outlet product temperature by the main control process more stable.

Preferably, the humidity control method of the present invention can further include a start-up control step that is executed prior to the main control step. In this start-up control, steam is supplied into the rotor with a start-up flow rate higher than the reference flow rate as a supply flow rate.

Execution of such a start-up control process is performed when the first deviation reaches within the seventh threshold, or the second deviation between the target temperature and the temperature of the steam at the outlet of the rotor reaches within the eighth threshold, Alternatively, it is stopped when a predetermined startup period has elapsed since the start of startup control.

Furthermore, the humidity control method of the present invention can further include a switching control process executed between the start-up control process and the main control process. This switching control step selects a switching control area corresponding to the first deviation from a plurality of switching control areas divided according to the magnitude and positive / negative of the first deviation, and in the selected switching control area The supply flow rate is controlled according to a control procedure.
The humidity control method of the present invention described above is suitable for humidity control of leaf tobacco as a tobacco raw material.

Since the humidity control method for tobacco material according to the present invention only controls the supply flow rate of the steam based on the first deviation between the outlet product temperature of the tobacco material and the target temperature, the target product temperature of the tobacco material is targeted. Can easily adjust to temperature. As a result, the tobacco material after conditioning can contain a sufficient amount of water.

It is the schematic of the humidity controller which performs the humidity control method of this invention. FIG. 2 is a functional block diagram illustrating functions of the humidity controller in FIG. 1. It is a graph which shows the change of the outlet product temperature and outlet steam temperature of tobacco raw material during start-up control. 5 is a graph showing a plurality of control areas included in switching control. It is a graph for demonstrating the end time of switching control. 5 is a graph showing a plurality of control areas included in FF control. It is a graph for demonstrating FB control performed in parallel with FF control. It is a figure for demonstrating the sampling of the deviation between target temperature and outlet product temperature for FB control, and calculation of an average deviation.

Before describing the humidity control method for tobacco raw materials according to the present invention, an outline of a humidity controller that executes the humidity control method will be described below with reference to FIG.
The humidity controller includes a cylindrical hollow rotor 10, which has a raw material inlet 12 that receives leaf tobacco (hereinafter simply referred to as a raw material) as a tobacco raw material and a raw material outlet 14 that discharges the humidity-controlled raw material. . Here, the raw material is a mixture of a plurality of types of leaf tobacco, and this mixture is used for producing a specific brand of cigarette.

The rotor 10 is rotatable in one direction, and the raw material supplied into the rotor 10 through the raw material inlet 12 is transferred through the rotor 10 from the raw material inlet 12 toward the raw material outlet 14 as the rotor 10 rotates. In the transfer process, the raw material is conditioned by steam supplied into the rotor 10, specifically, steam. The moisture-conditioned material is discharged from the material outlet 14 to the conveyance path, and is conveyed on the conveyance path toward a subsequent processing station (not shown).

In order to supply steam to the rotor 10, the humidity controller further includes a steam supply path 16, and the supply path 16 includes an internal space of the rotor 10 in a part thereof. Specifically, the supply path 16 has a steam inlet 18 and a steam outlet 20 each opened in the rotor 10, and is positioned on the steam inlet 18 on the raw material inlet 12 side, and the steam outlet 20 is positioned on the raw material outlet 14 side. .

The supply path 16 has a steam supply source, specifically, an upstream portion extending from the boiler chamber to the steam inlet 18 of the rotor 10 and a downstream portion extending from the steam outlet 20 of the rotor 10. A diaphragm-type steam flow controller 22 and a steam flow meter 24 are respectively arranged in the upstream portion of the supply path 16, and the downstream portion of the supply path 16 is open to the atmosphere at the end thereof.

The steam flow controller 22 and the steam flow meter 24 are electrically connected to the calculator 26, respectively. The calculator 26 is supplied with the target value Qo of the steam flow to be supplied into the rotor 10 and the actual steam flow Qa measured by the steam flow meter 24, and the calculator 26 sets the actual steam flow Qa to the target value. The operation of the steam flow regulator 22 is controlled to match Qo.

A temperature sensor 28 is disposed at the raw material outlet 14, and this temperature sensor 28 measures the outlet product temperature Ta of the raw material discharged from the rotor 10. On the other hand, a temperature sensor 30 is disposed in the downstream portion of the supply path 16, and this temperature sensor 30 measures the exhaust temperature Ts of the steam discharged from the rotor 10.
The outlet product temperature Ta and the exhaust gas temperature Ts are supplied as electric signals to the computing unit 32, and the steam flow target value Qo is calculated based on the computing unit 32, the outlet product temperature Ta, the exhaust gas temperature Ts and various set values. The target value Qo is supplied to the calculator 26. The set value includes the brand of the raw material and the capacity of the rotor 10.

As apparent from FIG. 2, the computing unit 32 cooperates with the computing unit 26 to execute the start-up control process, the switching control process, and the cascade control process, and details of these control processes will be described in detail below.
Start-up control process When the humidity controller described above is operated, that is, when the raw material is supplied into the rotor 10, the computing unit 32 sets the target value Qo of the steam flow rate (the supply flow rate of steam to the rotor 10). The startup flow rate Qst (kg / h) is set, and this startup flow rate Qst is supplied to the calculator 22. Here, the startup flow rate Qst is a unique value determined on the basis of the aforementioned set value. Therefore, during the start-up control process, the actual steam flow rate Qa is adjusted to the start-up flow rate Qst.

The start-up control process described above ends when any of the following three transition conditions 1-3 is satisfied.
Transition condition 1: Deviation Δt ′ (= To−Ts) between the target temperature To of the raw material at the raw material outlet 14 and the exhaust temperature Ts is within the threshold value Th_a.
Transition condition 2: The deviation Δt (= To−Ta) between the target temperature To of the raw material and the outlet product temperature Ta is within the threshold Th_b.
Transition condition 3: The elapsed time from the start of the start-up control process has reached T1.

The target temperature To described above is a unique value set according to the brand of the raw material, and the threshold values Th_a and Th_b are 2 ° C. and 5 ° C., for example.
As is apparent from FIG. 3, the exhaust temperature Ts normally tends to rise faster than the outlet product temperature Ta. Therefore, in addition to the transition condition 2 described above, the transition condition 1 is added, so that the startup control is performed. The process can be completed promptly. Further, the transition condition 3 prevents the period of the start-up control process from becoming undesirably long.

When any of the above-described transition conditions 1-3 is satisfied, the computing unit 32 ends the start-up control process and executes the following switching control process.
Here, first, the calculator 32 changes the target value Qo of the steam flow rate from the startup flow rate Qst to the reference flow rate Qb. This reference flow rate Qb is smaller than the startup flow rate Qst, and is a unique value determined based on the above-described set value, similarly to the startup flow rate Qst.

The computing unit 32 includes a control map for switching control as shown in FIG. This control map is a plurality of control areas divided by the magnitude of the deviation Δt and positive and negative, more specifically, the dead band R1, and positive and negative cubic function controls defined on both sides of the dead band R1, respectively. The regions R2 and R3 have positive and negative fixed control regions R4 and R5 defined outside the cubic function control regions R2 and R3, respectively.

When the deviation Δt satisfies the following expression, the dead band R1 is selected.
-Th_d ≦ Δt ≦ Th_c
Here, as is apparent from FIG. 4, the threshold values Th_c, -Th_d are small positive or negative values of 1 ° C. or less. The threshold values Th_c, | -Th_d | may be the same.
Since the deviation Δt is small when the dead zone R1 is selected, the calculator 32 maintains the target value Qo of the steam flow rate at the reference flow rate Qb. Therefore, in the dead zone R1, the actual supply flow rate Qa is adjusted to the reference flow rate Qb.

When the deviation Δt satisfies the following equation, the positive-side cubic function control region R2 is selected.
Th_c <Δt ≦ Th_e
Here, the threshold value Th_e is a positive value (for example, 4 ° C.) larger than the threshold value Th_c.
When the cubic function control region R2 is selected, the calculator 32 calculates a positive correction flow rate C1 based on the cubic function F1 [(a1 x Δt) ³ ] of the deviation Δt. Here, a1 is a coefficient. Then, the calculator 32 changes the target value Qo of the steam flow rate to the supply flow rate Qc1 (= Qb−C1) in which the correction flow rate C1 is reflected in the reference flow rate Qb. Therefore, in the cubic function control region R2, the actual supply flow rate Qa is adjusted to the supply flow rate Qc1.

Here, since the corrected flow rate C1 is calculated based on the cubic function F1 of the deviation Δt, it increases according to the cubic curve as the deviation Δt increases. Therefore, the supply flow rate Qc1 does not decrease much from the reference flow rate Qb if the deviation Δt is small, but decreases more rapidly than the reference flow rate Qb as the deviation Δt is large. As a result, the outlet product temperature Ta of the raw material effectively decreases toward the target temperature To according to the magnitude of the deviation Δt.

On the other hand, when the deviation Δt satisfies the following equation, the negative-side cubic function control region R3 is selected.
-Th_f ≦ Δt <-Th_d
Here, the threshold value -Th_f is a negative value larger than the threshold value -Th_d (for example, about -3.2 ° C.).
When the cubic function control region R3 is selected, the calculator 32 calculates the corrected flow rate C2 based on the cubic function F2 [(a2 × Δt) ³ ] of the deviation Δt. Here, a2 is a coefficient.

In this case, the computing unit 32 changes the target value Qo of the steam flow rate to the supply flow rate Qc2 (= Qb−C2) in which the corrected flow rate C2 is reflected in the reference flow rate Qb. Here, since the deviation Δt is a negative value, the corrected flow rate C2 calculated based on the cubic function F2 of the deviation Δt is also a negative value. Therefore, in the cubic function control region R3, the supply flow rate Qc2, that is, the actual steam flow rate Qa effectively increases according to the magnitude of the deviation Δt, and as a result, the raw material outlet product temperature Ta becomes the target temperature To. Ascend quickly.
Thus, the adoption of the above-mentioned cubic function is not only useful for effectively changing the outlet product temperature Ta of the raw material toward the target temperature To, but also regarding the calculation of the correction flow rates C1 and C2 at the deviation Δt. Facilitates positive or negative handling.

Further, when the deviation Δt satisfies the following equation, the fixed control region R4 is selected.
Th_e <Δt
In this case, the calculator 32 calculates the supply flow rate Qc3 as the steam flow target value Qo based on the following equation.
Qc3 = Qb-C3 (= F1 [(a1
x Th_e) ³ ])
Therefore, in the fixed control region R4, the actual steam flow rate Qa is adjusted to the supply flow rate Qc3.

Here, since the correction flow rate C3 is a positive value, the supply flow rate Qc3 is limited to a certain minimum value, and in this state, the outlet product temperature Ta is lowered toward the target temperature To.
On the other hand, when the deviation Δt satisfies the following expression, the positive fixed control region R5 is selected.
Δt <-Th_f
In this case, the calculator 32 calculates the supply flow rate Qc4 as the steam flow target value Qo based on the following equation.
Qc4 = Qb-C4 (= F2 [a2
x (-Th_f) ³ ])
Here, since the correction flow rate C4 is a negative value, the supply flow rate Qc4 is limited to a certain maximum value. Therefore, in the fixed control region R5, the actual steam flow rate Qa is adjusted to the supply flow rate Qc4. As a result, the raw material outlet product temperature Ta is quickly raised toward the target temperature To.

The switching control described above ends when any of the following transition conditions 4 and 5 is satisfied.
Transition condition 4: The deviation Δt is within the threshold value Th_g (see FIG. 5).
Transition condition 5: The elapsed time has reached T2 from the start of the switching control.
Here, the threshold value Th_g satisfies the relationship of the following equation.
Th_g <Th_a

When the transition condition 3 or 4 is satisfied, the computing unit 32 ends the switching control process and executes the following cascade control process.
Cascade control process This cascade control process includes a feed forward (FF) control process as a main control process and a feedback (FB) control process as a sub control process. Hereinafter, the FF control process and the FB control process will be described below. To do.

The FF control process The computing unit 32 further includes a control map for the FF control process as shown in FIG. 6, and this control map includes a plurality of control areas divided by the magnitude of the deviation Δt and the positive and negative. Band R6, positive and negative cubic function control areas R7 and R8 respectively defined on both sides of the dead band R6, positive and negative sides defined outside the cubic function control areas R7 and R8, respectively. Primary function control areas R9, R10, and positive and negative fixed control areas R11, R12 respectively defined outside the linear function control areas R9, R10.

When the deviation Δt satisfies the following expression, the dead band R6 is selected.
-Th_i ≦ Δt ≦ Th_h
Here, as is apparent from FIG. 6, the threshold values Th_h and -Th_i are small positive or negative values of 1 ° C. or less. Note that the threshold values Th_h and | -Th_i | may be the same.

When the dead zone R6 is selected, since the deviation Δt is small, the calculator 32 maintains the target value Qo of the steam flow rate at the reference flow rate Qb. That is, in the dead zone R6, the actual steam flow rate Qa is adjusted to the reference flow rate Qb.
When the deviation Δt satisfies the following equation, the positive-side cubic function control region R7 is selected.
Th_h <Δt ≦ Th_j
Here, the threshold value Th_j is a positive value (for example, 3 ° C.) larger than the threshold value Th_h.
When the cubic function control region R7 is selected, the computing unit 32 computes a positive correction flow rate C5 based on the cubic function F3 [(a1 x Δt) ³ ] of the deviation Δt, and obtains the steam flow target value Qo. Change the supply flow rate Qc5 (= Qb-C5) to reflect the correction flow rate C5 in the reference flow rate Qb. Therefore, in the cubic function control region R7, the actual steam flow rate Qa is adjusted to the supply flow rate Qc5.

On the other hand, when the deviation Δt satisfies the following equation, the negative-side cubic function control region R8 is selected.
-Th_k ≦ Δt <-Th_i
Here, the threshold value -Th_k is a negative value larger than the threshold value -Th_i (for example, about -2.5 ° C.).
When the cubic function control region R8 is selected, the calculator 32 calculates the negative correction flow rate C6 based on the cubic function F4 [(a2 x Δt) ³ ] of the deviation Δt, and the correction flow rate C6 is calculated as the reference flow rate Qb. The supply flow rate Qc6 (= Qb-C6) reflecting the above is set as the target value Qo of the steam flow rate. Therefore, in the cubic function control region R8, the actual steam flow rate Qa is adjusted to the supply flow rate Qc6.

Here, as is apparent from the description of the switching control described above, the correction flow rates C5 and C6 are calculated based on the cubic functions F3 and F4 of the deviation Δt, respectively, and therefore the supply flow rates Qc5 and Qc6 are the reference flow rates. Compared with Qb, it is decreased or increased according to the magnitude of the deviation Δt, and as a result, the outlet product temperature Ta of the raw material is effectively changed toward the target temperature To.
Again, it goes without saying that positive or negative handling of the deviation Δt is facilitated for the calculation of the correction flow rates C5 and C6.

When the deviation Δt satisfies the following expression, the positive-side linear function control region R9 is selected.
Th_j <Δt ≦ Th_l
Th_l is larger than Th_j (for example, 5.5 ° C.).
When the primary function control region R9 is selected, the calculator 32 calculates the positive correction flow rate C7 based on the linear function F5 (b1 x Δt) of the deviation Δt. b1 is a coefficient. Then, the calculator 32 sets the supply flow rate Qc7 (= Qb−C7) in which the correction flow rate C7 is reflected in the reference flow rate Qb as the target value Qo of the steam flow rate. Therefore, in the linear function control region R9, the actual steam flow rate Qa is adjusted to the supply flow rate Qc7.

On the other hand, when the deviation Δt satisfies the following equation, the negative-side linear function control region R10 is selected.
-Th_m ≦ Δt <-Th_k
-Th_m is a negative value larger than -Th_k (for example, -4.3 ° C).
When the linear function control region R10 is selected, the calculator 32 calculates the negative correction flow rate C8 based on the linear function F6 (b2 x Δt) of the deviation Δt. b2 is a coefficient. Then, the computing unit 32 sets the supply flow rate Qc8 (= Qb−C8) in which the correction flow rate C8 is reflected in the reference flow rate Qb as the target value Qo of the steam flow rate. Therefore, in the linear function control region R10, the actual steam flow rate Qa is adjusted to the supply flow rate Qc8.

Here, the corrected flow rates C7 and C8 are calculated based on the linear functions F5 and F6 of the deviation Δt, respectively, and thus become values proportional to the magnitude of the deviation Δt. Accordingly, the supply flow rates Qc7 and Qc8 are decreased or increased according to the deviation Δt. As a result, the raw material outlet product temperature Ta is quickly changed toward the target temperature To.

Further, when the deviation Δt satisfies the following equation, the positive fixed control region R11 is selected.
Th_l <Δt
In this case, the calculator 32 calculates the supply flow rate Qc9 based on the following equation, and sets this supply flow rate Qc9 to the target value Qo of the steam flow rate.
Qc9 = Qb-C9 (= F5 (b1
x Th_l))
Here, since the correction flow rate C9 is a positive value, the supply flow rate Qc9 is limited to a certain minimum value, and the outlet product temperature Ta of the raw material is lowered toward the target temperature To.

On the other hand, when the deviation Δt satisfies the following equation, the negative fixed control region R12 is selected.
Δt <-Th_m
In this case, the calculator 32 calculates the supply flow rate Qc10 based on the following equation, and sets the supply flow rate Qc10 to the target value Qo of the steam flow rate.
Qc10 = Qb-C10 (= F6 (b2
x -Th_m))

Here, since the correction flow rate C10 is a negative value, the supply flow rate Qc10 is limited to a certain maximum value, and the outlet product temperature Ta of the raw material is raised toward the target temperature To.
In the above-described FF control process, humidity control of the raw material is executed by making the outlet product temperature Ta of the raw material coincide with the target temperature To, so that it is possible to easily give the moisture content necessary for the raw material after humidity control.

Further, the combination of the above-described cubic function control areas R7, R8 and linear function control areas R9, R10 quickly eliminates the instantaneous change in the outlet product temperature Ta, and the raw material outlet product temperature Ta is set to the target temperature To. To maintain stable.
Further, since the positive and negative fixed control regions R11 and R12 are included in the control region in the FF control step, the steam supply flow rate to the rotor 10 increases excessively even if the deviation Δt is large. Will never be done.

Furthermore, even if the initial moisture amount or supply amount of the raw material supplied to the raw material inlet 12 of the rotor 10 is changed, this change does not affect the execution of the FF control process, and the raw material outlet product temperature Ta is the target temperature. Adjusted to To.
The above-mentioned FF control process is performed at a predetermined transition waiting time when shifting from the cubic function control area R7 to the linear function control area R9 or when shifting from the cubic function control area R8 to the linear function control area R10. Can include time.

FB Control Process As shown in FIG. 7, the FB control process is executed in parallel with the above-described FF control process.
Specifically, the computing unit 32 starts the FB control process after a predetermined waiting time T3 has elapsed from the start of the cascade control process.

After the start of the FB control process, the calculator 32 repeats sampling of the deviation Δt at a predetermined period in a predetermined calculation period T4, and calculates an average deviation Δt_av of the deviation Δt within the calculation period T4.
Here, it is assumed that the deviation Δt is changed during the calculation period T4 as shown in (a), (b), and (c) of FIG. In the case of (a) in FIG. 8, the average deviation Δt_av is 0, but in the cases of (b) and (c) in FIG. 8, the average deviation Δt_av has values of + d and −d, respectively.

When the average deviation Δt_av is thus obtained, the calculator 32 calculates a positive or negative correction flow rate C11 with respect to the reference flow rate Qb based on the average deviation Δt_av, and uses the correction flow rate C11 to calculate the reference flow rate Qb. Is reset to the new reference flow rate Qb '.

Specifically, the reference flow rate Qb ′ is obtained based on the following substitution formula.
Qb '← Qb-C11
Such a reference flow rate Qb ′ becomes effective when the next FB execution period (reset control area) T5 starts from the end of the calculation period T4, and is used in the FF control process described above. Thereafter, the calculation of the correction flow rate C11 in the calculation period T4 and the resetting of the reference flow rate Qb ′ in the FB execution period T5 are repeatedly executed.

As is apparent from FIG. 7, the above-mentioned FB control step resets the reference flow rate Qb to the reference flow rate Qb ′ in accordance with the continuous slight change in the raw material outlet product temperature Ta. Therefore, by using the reference flow rate Qb 'in the FF control step, the raw material outlet product temperature Ta can be maintained at the target temperature To with higher accuracy and stability. That is, the combination of the FB control process and the FF control process, that is, the cascade control process, is excellent in the humidity control of the raw material focusing on the raw material outlet product temperature Ta.

The present invention is not limited to the humidity control method of the embodiment described above, and various modifications can be made.
For example, in the description of the start-up control process, the switching control process, and the cascade control process described above, various temperatures are shown, but these temperatures are merely examples and can be changed.
Further, when the brand of the raw material supplied to the rotor 10 is changed during the humidity conditioning of the raw material, that is, when the target temperature To is changed, as shown by the broken line in FIG. Is started from the switching control step.
Furthermore, the raw material is not limited to leaf tobacco, and the humidity control method of the present invention can be applied to various raw materials.

10: Rotor, 12: Raw material inlet, 14: Raw material outlet, 16: Steam supply path, 18: Steam inlet, 20: Steam outlet, 22: Steam flow regulator, 24: Steam flow rate, 26: Calculator, 28: Temperature sensor, 30: Temperature sensor, 32: Calculator, R6: Dead band, R7, R8: Cubic function control area, R9, R10: Linear function control area, R11, R12: Fixed control area, T4: Calculation period , T5: FB execution period

Claims

Tobacco material and steam is supplied into a rotor, and the tobacco material is conditioned in the process of passing the tobacco material through the rotor.
Detecting the outlet product temperature of the tobacco raw material immediately after being discharged from the outlet of the rotor when the steam is supplied into the rotor at a supply flow rate;
Obtaining a first deviation between the target temperature of the tobacco raw material at the outlet and the outlet product temperature;
A main control step of controlling the supply flow rate based on a reference flow rate of steam based on the first deviation;
The main control step includes
Selecting a control area corresponding to the first deviation from a plurality of control areas divided according to the magnitude and positive / negative of the first deviation;
A method for conditioning humidity of a tobacco material, wherein the supply flow rate of the steam is controlled according to a control procedure in a selected control region.
The control area is
A dead band selected when the first deviation is between a positive first threshold value and a negative second threshold value, wherein the supply flow rate is maintained at the reference flow rate;
According to a corrected flow rate selected when the first deviation exceeds the first threshold and is within a positive third threshold greater than the first threshold, and is calculated based on a cubic function of the first deviation, A positive-side cubic function control range for reducing the supply flow rate from the reference flow rate;
According to the corrected flow rate selected when the first deviation exceeds the negative two threshold values and is within a negative fourth threshold value that is larger than the second threshold value, and is calculated based on a cubic function of the first deviation. The method of claim 1, further comprising: a negative third-order function control region that increases the supply flow rate from the reference flow rate.
The control area is
A corrected flow rate that is selected when the first deviation exceeds the positive third threshold value and is within a positive fifth threshold value that is greater than the third threshold value and is calculated based on a linear function of the first deviation. And a positive-side linear function control region for reducing the supply flow rate from the reference flow rate,
A corrected flow rate that is selected when the first deviation exceeds the negative fourth threshold value and is within a negative sixth threshold value that is greater than the fourth threshold value and is calculated based on a linear function of the first deviation. In accordance with the negative linear function control range to increase the supply flow rate from the reference flow rate,
The method for conditioning humidity of a tobacco material according to claim 2, further comprising:
The control area is
A positive fixed control region that is selected when the first deviation exceeds the positive fifth threshold and limits the supply flow rate to a certain lower limit flow rate;
A negative fixed control range that is selected when the first deviation exceeds the negative sixth threshold and limits the supply flow rate to a certain upper limit flow rate;
The method for conditioning a tobacco material according to claim 1.
Further comprising a sub-control step executed in parallel with the main control step,
The sub-control step includes
Includes a reset control area for the reference flow that is repeated periodically,
2. The method of claim 1, wherein the reset control area resets the reference flow rate based on an average value of the first deviations during a certain period.
It further includes a start-up control step executed prior to the main control step,
2. The humidity control method for tobacco material according to claim 1, wherein in the start-up control step, steam is supplied into the rotor with a start-up flow rate larger than the reference flow rate as the supply flow rate.
The start-up control step is executed when the first deviation reaches within the seventh threshold or the second deviation between the target temperature and the temperature of the steam at the rotor outlet falls within the eighth threshold. The humidity control method for tobacco material according to claim 6, wherein the humidity control method is stopped when reaching or when a predetermined start-up period has elapsed from the start of the start-up control.
A switching control step executed between the start-up control step and the main control step;
The switching control step selects a switching control area corresponding to the first deviation from a plurality of switching control areas divided according to the magnitude and positive / negative of the first deviation,
Controlling the supply flow rate according to a control procedure in the selected switching control area;
The method for conditioning a tobacco material according to claim 1.
The method for conditioning a tobacco material according to claim 1, wherein the tobacco material is leaf tobacco.