JPH0113832B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic leaf tobacco drying control method and apparatus for automatically controlling the dehydration rate of leaf tobacco by constantly detecting changes in the weight of leaf tobacco during drying.

Tobacco leaf drying is the process of turning harvested fresh leaves into desired dried leaves. However, simply removing the moisture in the leaves may not produce leaf tobacco with excellent aroma or flavor, or may cause problems such as grassy smell and pungent taste. Unpleasant components are produced, making it unsuitable for smoking. In order to produce excellent aroma and taste in leaf tobacco, the activity of leaf enzymes is promoted during the first half of the drying process.
It is essential to decompose the substances that cause grassy odor and irritation, adjust the color, and dehydrate and dry.

For this reason, leaf tobacco is generally dried during the yellowing period.
The drying process is divided into a color fixation stage and a backbone drying stage. The yellowing period is a period in which the content of the leaf changes, i.e., dehydration reaches a level where enzymes can work easily, and the appropriate temperature is maintained to promote enzyme activity. In addition to dehydrating while maintaining the skin, from the middle stage onwards, it is a period in which moderate dehydration is carried out in order to maintain the color and luster.
This is a period in which the dehydration rate is increased to remove water inside the bone.

As mentioned above, throughout the entire tobacco drying period,
The amount of dehydration has a close relationship with leaf tobacco components (quality), and if the dehydration rate is incorrectly adjusted during the drying period, the quality of the leaf tobacco will be significantly impaired. for example,
Rapid dehydration during the yellowing stage weakens leaf life and enzymes lose their activity, causing the contents to dry up without being decomposed. Conversely, even if the amount of dehydration is small, the enzymes work slowly and last for a long period of time. It will require. Even during the color fixation stage, if the cells are not dehydrated and fixed while they still have vitality, oxidative enzymes will act and the quality will deteriorate, such as leaves turning brown. Thus, it is extremely important to appropriately control the amount of dehydration (change in leaf weight) throughout the drying period.

By the way, in the past, the speed of dehydration was adjusted by controlling the air conditioning by controlling the dry bulb temperature and wet bulb temperature in the drying chamber, and draining the evaporated moisture.
In order to determine the amount of dehydration in the leaves (changes in the weight of the leaves), operators had to rely on their eyes or senses, which often led to lack of proper judgment and failure.

In view of the above, the present invention detects the wet bulb temperature, dry bulb temperature, and weight change of the leaf tobacco in the drying chamber, and maintains the wet bulb temperature substantially constant throughout the entire drying period, and detects the detected weight change of the leaf tobacco. Based on this, the dry bulb temperature is automatically adjusted by controlling the heating source so as to maintain the weight ratio of the leaves to the leaf weight before drying, which has been set in advance for the drying time.
It constantly and accurately detects changes in the weight of leaf tobacco throughout the entire drying period, and automatically adjusts the dry bulb temperature in the drying chamber based on the accurate detection results, making it possible to maintain the optimal amount of water removal throughout the entire drying period. Therefore, it is an object of the present invention to provide an automatic leaf tobacco drying control method and device that can extremely easily obtain high-quality dried leaf tobacco. A preferred embodiment will be described below.

In FIG. 1, reference numeral 1 denotes a drying chamber, and within the drying chamber 1, ventilation chambers 3 and 4 are formed above and below a leaf tobacco storage section 2. 4 communicate with each other through a communication chamber 5 on one side of the leaf tobacco storage section 2, forming an air circulation path 6. An intake port 7 and an exhaust port 8 are opened in the air circulation path 6.
The exhaust port 8 is provided with a damper 9 for adjusting its opening/closing or opening degree. Furthermore, an air circulation fan 10 is provided in the communication chamber 5 of the air circulation path 6.
A burner 11 as a heat source is arranged on the discharge side thereof.

On the other hand, the drying chamber 1 is supported so as to be movable up and down without being fixed to the installation section 12, and strain gauges 13, 13 are interposed between the installation section 12 and the bottom of the drying chamber 1 to detect changes in weight as electrical signals. drying room 1
The change in the weight of the leaf tobacco, that is, the change in the weight of the stored leaf tobacco, is detected as an electrical signal by the strain gauges 13, 13. A wet bulb thermometer 14 and a dry bulb thermometer 15 are provided in the drying chamber 1. The detection signals of the wet bulb thermometer 14, dry bulb thermometer 15, and strain gauges 13, 13 are sent to the drying control device 16.
The damper 9 is sent to the drying control device 16.
and burner 11 are connected (FIG. 2).
That is, the drying control device 16 controls the damper 9 to keep the wet bulb temperature in the drying chamber 1 substantially constant,
The opening degrees of the intake port 7 and the exhaust port 18 are automatically adjusted, and the dry bulb temperature is controlled so as to maintain the weight ratio of the leaves to the leaf weight before drying, which is set in advance for the drying time. It operates to control the burner 11 so as to maintain the temperature.

Next, the operation of the present invention will be explained.

Now, when drying leaf tobacco, if a predetermined amount of freshly harvested leaves is suspended and stored in the leaf tobacco storage section 2 in the drying chamber 1, the weight of the drying chamber 1 will increase by the amount of stored leaf tobacco, so the weight change will be distorted. Gauge 1
3 and 13, it is detected as an electrical signal. Further, the wet bulb temperature and dry bulb temperature in the drying chamber 1 are detected as electrical signals by a wet bulb thermometer 14 and a dry bulb thermometer 15, respectively. These strain gauges 13, 13, wet bulb thermometer 14 and dry bulb thermometer 1
The electrical signal sent from 5 becomes an input to a drying control device 16. As mentioned above, the leaf tobacco drying process is divided into the yellowing period, color fixation period, and bone drying period, and the wet bulb temperature in the drying chamber 1 is approximately constant at 36°C to 42°C throughout the entire drying period. The wet bulb temperature is gradually increased at a preset rate of increase relative to the drying time (see Figure 3). The above operations are automatically controlled by the drying control device 16. The optimal amount of dehydration of leaf tobacco with respect to drying time has been determined in advance through experiments, but if this is expressed in terms of changes in the weight of leaf tobacco, that is, leaf weight ratio, the upper leaves are shown in Figure 3, and the lower leaves are shown in Figure 3. As shown in Figure 4, if the leaf weight at the start of drying is 100%,
The leaf weight ratio at the end of drying is 15%. Note that the upper or lower limit value of the leaf weight ratio is also permissible within a certain range, and this range is wide from the middle to the late drying period. This is because the early stage of drying is a period when enzymes are active, and it is necessary to maintain the temperature and appropriate amount of moisture in the leaf, whereas from the middle stage of drying onwards, dehydration becomes the main problem.

By the way, the weight ratio of the leaf tobacco is constantly detected as an electric signal by the strain gauges 13, 13 throughout the drying period, and the signal is sent to the drying control device 16, so that the weight ratio of the leaf tobacco (upper leaf or lower leaf) is detected during the drying period. If the weight ratio falls above or below the allowable range shown in FIGS. 3 and 4, the dehydration rate is automatically adjusted to control the drying temperature and return the weight ratio of the leaf tobacco to a predetermined range. Therefore, the leaf tobacco being dried is dried at an appropriate dehydration rate based on the accurate amount of dehydration, and high quality dried leaf tobacco can be obtained.

In short, the present invention detects the wet bulb temperature, dry bulb temperature, and weight change of the leaf tobacco in the drying chamber, keeps the wet bulb temperature substantially constant throughout the entire drying period, and uses the detected weight change of the leaf tobacco to The dry bulb temperature is automatically adjusted by controlling the heating source so as to maintain the weight ratio of the leaves before drying to the leaf weight before drying, which is set in advance for the drying time, so the weight ratio of the leaf tobacco is maintained throughout the entire drying period. The dry bulb temperature in the drying chamber is automatically adjusted based on the accurate detection results, and the optimum dehydration amount can be maintained throughout the entire drying period. This has the effect of producing high quality dried leaf tobacco.

[Brief explanation of drawings]

The drawings show one embodiment of the apparatus according to the present invention, and FIG. 1 is a schematic side sectional view of the dryer, and FIG.
The figure is a block diagram of the control section, FIG. 3 is a standard drying progress chart for upper leaf tobacco, and FIG. 4 is a standard drying progress chart for lower leaf tobacco. 1...Drying room, 11...Burner, 13...Strain gauge,
14...Wet bulb thermometer, 15...Dry bulb thermometer, 16...Drying control device.

Claims (1)

[Scope of Claims] 1. The wet bulb temperature, dry bulb temperature, and weight change of the leaf tobacco in the drying chamber are detected respectively, the wet bulb temperature is kept substantially constant throughout the entire drying period, and the detected weight change of the leaf tobacco is detected. A leaf tobacco drying automatic control method characterized in that the dry bulb temperature is automatically adjusted by controlling a heating source so as to maintain a weight ratio of leaves to undried leaf weights set in advance for drying time based on . 2. A wet bulb thermometer and a dry bulb thermometer that detect the wet bulb temperature and dry bulb temperature in the drying room as electrical signals,
Each device is equipped with a strain gauge that detects the weight change of the leaf tobacco during drying as an electrical signal, keeps the wet bulb temperature approximately constant throughout the entire drying period, and adjusts the drying time to a preset temperature based on the detected weight change of the leaf tobacco. An automatic leaf tobacco drying control device comprising a drying control device that automatically adjusts a dry bulb temperature by controlling a heating source so as to maintain a weight ratio of the leaves to the weight of the leaves before drying.