JPS6215190B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention maintains the wet bulb temperature in the drying chamber at a substantially constant value throughout the entire drying process, and changes the dry bulb temperature every time the amount of dehydration of leaf tobacco, that is, the intake and exhaust amount of the drying chamber reaches an equilibrium state. The present invention relates to an automatic leaf tobacco drying method and device for increasing the temperature in fixed steps.

Unlike the drying of general agricultural products, leaf tobacco drying involves not only simple dehydration and drying, but also a curing process that promotes chemical changes in the tobacco content in order to bring out the distinctive color and aroma of leaf tobacco. It is also necessary to dehydrate and dry the back bone portion. Therefore, the drying process can be roughly divided into
Drying is progressed in three stages: the yellowing stage, which maintains the mesophyll temperature at an appropriate level, the color fixation stage, which mainly dehydrates the mesophyll, and the midbone drying stage, which dries the midbone.

By the way, as a drying control method to ensure that the drying process as described above runs well, the wet bulb temperature in the drying chamber is maintained at a constant value (e.g. approximately 38°C) throughout the entire drying process, and the dry bulb temperature is adjusted over a certain period of drying time. A drying method has been developed in which the drying temperature is increased step by step by a predetermined value.
However, in this method, the dry bulb temperature is increased at preset intervals, so no matter how carefully you set the time, the timing of the rise in the dry bulb temperature will depend on the progress of the drying of the leaf tobacco. In reality, it is not always suitable as an automatic control method for drying leaf tobacco.

In view of the above, the present invention maintains the wet bulb temperature at a substantially constant value and increases the drying temperature by a predetermined value each time the amount of dehydration of the leaf tobacco, that is, the intake and exhaust amount of the drying chamber reaches an equilibrium state. An automatic leaf tobacco drying method that can completely adapt to the drying progress state of leaf tobacco during drying, accurately raise the dry bulb temperature, and allow drying to proceed smoothly under complete automation. DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the method and apparatus of the present invention will be described below with reference to a preferred embodiment shown in the accompanying drawings.

In FIG. 1, 1 is a wet bulb temperature sensor, 2 is a dry bulb temperature sensor, and these wet bulb temperature sensors 1
A dry bulb temperature sensor 2 is placed inside the drying chamber. Reference numeral 3 denotes a proportional control circuit, 4 a damper, and 5 a hot air generator. The damper 4 controls the opening and closing of the intake and exhaust ports of the drying chamber. The hot air generator 5 has a built-in burner as a heat source, and the It supplies hot air for drying to. The proportional control circuit 3 controls the opening degree of the damper 4 and the heat source of the hot air generator 5 to maintain the wet bulb temperature and dry bulb temperature in the drying chamber at set values. That is, the proportional control circuit 3 includes a wet bulb temperature setting device 3a.
and a dry-bulb temperature setting device 3b, which receives signals from the wet-bulb temperature detector 1 and dry-bulb temperature detector 2 in the drying chamber, compares them with respective set values, and sets the wet-bulb temperature in the drying chamber. The opening degree of the damper 4 and the heat source of the hot air generator 5 are controlled so as to maintain the dry bulb temperature at a set value. Reference numeral 6 denotes a temperature increasing circuit, and this temperature increasing circuit 6 operates to automatically operate the dry bulb temperature setter 3b of the proportional control circuit 3 in the temperature increasing direction to increase the set value of the dry bulb temperature. The heating circuit 6 includes:
Throughout the entire drying time, from the start of drying to the yellowing period, the temperature is approximately 2℃, and during the color fixation period, the temperature is approximately 2℃ to 5℃.
℃, and during the midbone fixation period, the temperature was increased again to approximately 2℃ to 5℃.
A temperature increase control timer 6a for raising the temperature by 0.degree. C. is provided. Reference numeral 7 denotes a temperature increase command circuit, which receives a damper opening/closing control signal from the proportional control circuit 3, but for a period of time (for example, one hour) set in an operation control timer 7a built into it. ), one temperature increase command signal is sent to the temperature increase circuit 6 when the above signal is not received at all.

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

Now, when drying the leaf tobacco stored in the drying chamber, in the proportional control circuit 3, the wet bulb temperature setter 3a is set to a constant temperature (for example, 38°C), and the dry bulb temperature setter 3b is set to the initial temperature (for example, 40°C). ℃) and start drying. Changes in the wet bulb temperature and dry bulb temperature in the drying chamber are detected by the wet bulb temperature detector 1 and the dry bulb temperature detector 2, and the signals are sent to the proportional control circuit 3. The heat sources of the damper 4 and the hot air generator 5 are controlled so as to maintain the wet bulb temperature set by the wet bulb temperature setting device 3a and the dry bulb temperature set by the dry bulb temperature setting device 3b.

If the drying progresses for a certain period of time under the above conditions, the second
As shown in the figure, the amount of water removed from the leaf tobacco, that is, the amount of intake and exhaust in the drying chamber is in equilibrium, and the wet bulb temperature is maintained at a substantially constant value, so the proportional control circuit 3
A damper opening/closing control signal is not sent from. Therefore, when the time during which the damper opening/closing control signal is not sent out exceeds the set time of the operation control timer 7a in the temperature increase command circuit 7, the temperature increase command circuit 7 is activated and one temperature increase command signal is sent to the temperature increase circuit 6. The temperature increasing circuit 6 is connected to the dry bulb temperature setting device 3 in the proportional control circuit 3.
Automatically operate to raise the set temperature of b by one step. Therefore, the dry bulb temperature in the drying chamber is increased by a certain value, and the dehydration rate of the leaf tobacco is increased again. Next, drying progresses until an equilibrium state is reached. Once the equilibrium state is reached, the above operation is repeated again, and the leaf tobacco is dried. A rise in the indoor dry bulb temperature is measured.

Note that the temperature increase value for each stage is the temperature increase value of the temperature increase circuit 6.
It is predefined by the temperature increase control timer 6a.

As described above, according to the present invention, the dry bulb temperature is increased by a predetermined value each time the amount of dehydration of leaf tobacco, that is, the intake and exhaust amount of the drying chamber reaches an equilibrium state, so that the timing of increasing the dry bulb temperature can be adjusted. It can be completely adapted to the drying progress state, and the leaf tobacco can be dried well.

In short, the present invention maintains the dry bulb temperature in the drying chamber at a substantially constant value throughout the entire drying process by adjusting the intake and exhaust amount, and gradually increases the dry bulb temperature in the drying chamber by controlling the drying heat source. In the method of drying leaf tobacco, the dry bulb temperature is increased by a predetermined value each time the amount of dehydration of the leaf tobacco, that is, the amount of air intake and exhaust in the drying chamber is balanced, during the drying process. It is possible to accurately raise the dry bulb temperature by completely adapting to the conditions, and the effect is that the drying of leaf tobacco can be performed satisfactorily under complete automation.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention,
FIG. 1 is a block diagram showing the configuration of the apparatus, and FIG. 2 is an operating characteristic diagram showing the relationship between drying time, dewatering amount (suction/exhaust amount), and wet/dry bulb temperature. 1... Wet bulb temperature detector, 2... Dry bulb temperature detector, 3... Proportional control circuit, 4... Damper, 5...
Hot air generator, 6...Temperature increase circuit, 7...Temperature increase command circuit.

Claims (1)

[Scope of Claims] 1. The wet bulb temperature in the drying chamber is maintained at a substantially constant value throughout the entire drying process by adjusting its intake and exhaust volume, and the dry bulb temperature in the drying chamber is gradually increased by controlling the drying heat source. In the method of drying leaf tobacco while drying, the dry bulb temperature is increased by a predetermined value each time the dehydration amount of the leaf tobacco, that is, the intake and exhaust amount of the drying chamber reaches an equilibrium state, during the progress of the drying process. Automatic drying method. 2. In a drying chamber equipped with a damper that adjusts the opening and closing of the intake and exhaust ports and a hot air generator that supplies hot air into the drying chamber, the wet bulb temperature inside the drying chamber can be controlled by adjusting the degree of opening of the damper during the entire drying process. a proportional control circuit that maintains the dry bulb temperature at a substantially constant value through and controls the heat source of the hot air generator to maintain the dry bulb temperature at a set value;
In addition to providing a temperature increasing circuit that increases the dry bulb temperature setting value of the proportional control circuit step by step by a predetermined value, the damper opening/closing control signal is not sent from the proportional control circuit for a certain period of time preset by a timer. An automatic leaf tobacco drying device characterized in that the temperature increasing circuit is provided with a temperature increasing command circuit that sends a temperature increasing command signal for each step.