JPH0511936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a drying process in a tea manufacturing process, and to temperature control of tea leaves in this process.

Prior Art The rough rolling process, medium rolling process, fine rolling process, etc. in the tea manufacturing process are the drying processes of tea leaves, and each process is often performed with a dedicated device.

Each device is equipped with an automatically controlled heating device and blower device, and the end moisture value A (T1) set by the operator
The structure is such that the tea leaves are dried while adjusting the amount of heat supplied to the tea leaves along the drying rate curve (Fig. 4 l) determined from the end time T1.

In this case, if the drying speed is high, the amount of heat received by the tea leaves per unit time also increases, and the temperature of the tea leaves increases. Traditionally, the temperature of tea leaves during the drying process has been considered to be around human skin temperature (37° to 33°C), and if the tea leaf temperature deviates from this allowable range, the color, luster, shape, or taste of the tea will be lost, resulting in a significant drop in quality. Resulting in. This influence of tea leaf temperature is particularly evident in the processing of high-grade teas, which are particularly sensitive to drying conditions.

By the way, the conventional drying process (for example,
1097, Japanese Patent Application Laid-open No. 63-260), the tea leaf drying rate curve (including a straight line) determined as described above is simply executed faithfully, and the moisture value at the elapsed time t. Measure B(t) and draw the drying rate curve l
Once it is determined, the process proceeds regardless of the actual tea leaf temperature, and in some cases,
The tea leaf temperature may exceed the above-mentioned allowable temperature.

That is, the end moisture value A (T1), the end time
In setting T1, in reality, we hold the pre-treated tea leaves in our hands and judge by the feel of the wetness of the tea leaves, and even though the properties of the input tea leaves have changed, the value of the previous treatment is Since the end moisture value A(T1) and the end time T1 are set as they are, an imbalance may occur between the end moisture value A(T1) and the end time T1, and as a result, the drying rate may increase.

In addition, the tea leaf temperature reduces the drying speed (4th
(Fig. 1, drying rate curve l').

Problems to be Solved by the Invention It is an object of the present invention to provide a tea manufacturing method in which the temperature of tea leaves is maintained within an acceptable range in the drying step of the tea manufacturing process.

Means to solve the problem End moisture value A (T1) and end time T1 in tea making process
A drying process to be carried out along a drying curve determined by is set, and an allowable tea leaf temperature for this process is determined.

Measure the current temperature C(t) of the tea leaves.

It is determined whether the current tea leaf temperature C(t) or the predicted tea leaf temperature CH calculated based on this is within the above-mentioned allowable range.

If these are not within the above tolerance range, the end time
T1 is corrected to the correction end time T2 to maintain the tea leaf temperature within the above-mentioned allowable range.

Effect By correcting the set end time T1 to the corrected end time T2, the temperature of the tea leaves is maintained within an allowable range.

By keeping the tea leaf temperature within an acceptable range, deterioration in the quality of tea production is prevented.

Example FIG. 1 is a processing flow in the medium kneading machine.

In addition, this medium rolling machine has a control system (equipped with a CPU,
Except that a program (based on a so-called microcomputer) is set up to process the flow, it exhibits the same functions as the conventional one. That is, the drying speed of the tea leaves is maintained at a predetermined speed by adjusting the amount of hot air applied to the tea leaves undergoing rolling action and controlling the amount of heat supplied. To this end, the medium rolling machine is equipped with a controllable blower fan, a heating burner and a sensor for detecting the tea leaf temperature.

It is also equipped with various sensors, moisture measuring devices, etc.

In this example, the upper limit value UC (approximately 37°) and lower limit value LC (approximately 35°) are used as the permissible range of tea leaf temperature, and the predicted tea leaf temperature is used to determine the tea leaf temperature within the permissible range.
CH is used.

Before starting the flow, check the initial air volume, initial hot air temperature, rolling drum rotation speed, upper limit value UC, and lower limit value LC.
and various coefficients k1 to k4 (described later) are set in the medium kneading machine.

After the start, the end moisture value A (T1) and end time T1 set by the operator in step 1 are read, and then the drying cylinder rotates, the kneading hand attached to the main shaft rotates, and hot air is supplied by the blower and burner. , the sensor that detects the temperature of tea leaves, and other parts start operating, and the medium rolling machine goes into actual operation.

In step 2, the flags are set to f=0 and G=0,
The program moves to step 3 and the timer starts operating. This timer defines the cycle time of the flow and allows transition to step 4 every minute, and counts the elapsed time t in minutes.

In step 4, since this is the first time of operation and f=0, the judgment is NO and the process moves to step 7, where the current moisture value B(t) and the current tea leaf temperature C(t) are detected.

Next, in step 8, 1 is added to the flag G, and since the current flag is f=0, the judgment in step 9 is YES, and the process proceeds to step 10 to wait for 3 minutes until the moisture measurement becomes stable (described later). That is, in step 10, the presence or absence of a signal from the timer is detected to monitor whether t≧3, and while the determination is NO, the process returns to step 3, and in step 7, the current moisture value B(t) and the current moisture value are determined. While detecting the tea leaf temperature C(t), t≧
Wait until it becomes 3. During this time, 1 is added to the flag G every round.

When the moisture measurement becomes stable, proceed to step 11 and set the flag to f=1, and in step 12 set value A (T1),
Performs allocation processing (described later) based on T1. Then, in step 13, it is determined whether the flag G is G>2. This time, since G = 3 due to the standby at step 10, the judgment is YES, and the process proceeds to the judgment/correction process (described later) at step 14, and the correction end time T2, which is the result of the judgment/correction process, and the current setting at step 15. It is determined whether the specified end times T1 are the same.
If they are the same, proceed to step 18 for actual control (described later); if they are different, proceed to step 16 to correct the end time T2.
into T1, set flag G to G=0, and step
At step 17, allocation processing is performed based on the current moisture value B(t) and the correction end time T2. Then we reach step 18,
Actual control is performed based on the allocated results.

After the specified processing is completed in the actual control in step 18,
In step 19, the tea leaf extraction mode (described later) is determined, and if it is the water extraction mode, then in step 20,
If the mode is time extraction mode, proceed to step 21.

In step 20, the current moisture value B〓 becomes the final moisture value A
(T1), that is, [B(t)≦A
(T1)], and in step 21, it is monitored whether the current elapsed time t has reached the end time T1 (t≧T1). However, since this is the beginning of the operation, the decision in either case is NO, and the process returns to step 3 for the second processing.

In the second process, the process goes through the timer (step 3) and goes to step 4, where the flag is set to f=
1. Since G=0, the determination is YES and the process proceeds to step 5, where it is determined whether or not the set value has been changed.

Now, if there is no change, the answer is NO, so the process goes directly to step 7, where the current moisture value B(t) and the current tea leaf temperature C〓 are detected, and in step 8, the flag G is detected.
1 is added to , and in step 9 NO is set due to f = 1.
Therefore, proceed to step 13.

In step 13, the flag G is G=1 (if the judgment was YES in the previous step 15) and G=4 (if the judgment was NO in the previous step), so if G=1, the step is immediately executed.
18 and performs actual control again, and the following processing is the same as the first time. In addition, if G=4, the process moves to step 14 for judgment/correction processing, and the following steps are performed.
The process will be the same as the first time.

In step 5 of the second process, if there is a change in the set value A (T1), T1, the judgment is YES.
Therefore, in step 6, an allocation process is performed based on the corrected end time T2 and the initially set end moisture value A(T1), and the process moves to step 7, where the same process as the previous time is performed.

The processing from the third time onwards is the same as the second time.

As mentioned above, in this flow, the flow cycle is set to 1 minute by the timer (step 3),
Then, the current moisture value B(t) and the current temperature C(t) of the tea leaves are measured every minute. These measured values are stored in the microcontroller's RAM and made available to the CPU at any time.

The flag f is used to bypass step 5 and execute step 10 at the first time of processing, and from the next processing onward, to execute step 5 every time and bypass step 10. Flag G is used to bypass step 10. The end time in the correction process (step 14)
If there is no correction in T1, this step 14 is passed every time (every minute), and when the same correction is made, this step is bypassed in the next two cycles until the change in tea leaf temperature stabilizes, and the effect of the correction appears. The next judgment is made to wait until the next judgment is made.

The allocation process starts when the moisture value measurement becomes stable (step 10), and the judgment/correction process (step 10).
14), when the end time T1 is modified, and when the set value A(T1) and T1 are changed, this is done immediately, thereby increasing the responsiveness of the device in actual operation.

The judgment/correction process in step 14 is shown in FIG.

In this process, it is first checked in step 141 whether a command to determine the validity of the set value has been issued, and if it has not been issued, the process immediately returns to the original flow (in this case, there is no change in the end time), and If so, proceed to step 142.

Commands are set by the operator before or during the process.

That is, step 141 is provided because some workers are confident in their own know-how and do not like the set values to be changed.

Therefore, if there are no determination/correction commands throughout the entire process, the present invention will not be implemented.

Upper limit of tea leaf temperature allowed in step 142
UC and lower limit value LC are read, and in step 143, coefficients k1 (=1.5, this example) and k2 (=1.0, same) are applied to the current tea leaf temperature and the average change in tea leaves over the past 2 minutes, respectively.
Multiply by and add to find the predicted tea leaf temperature CH after 1 minute. In other words, the predicted tea leaf temperature CH is the current temperature C(t)
This is required based on the following.

In step 144, the differences U and L between the predicted tea leaf temperature CH and the upper limit UC and lower limit LC are determined. Step 145 is a judgment as to whether or not the predicted tea leaf temperature CH exceeds the upper limit value UC. If YES, that is, the predicted tea leaf temperature CH exceeds the upper limit UC, the coefficient k3 (=5.0, The corrected end time T2 is obtained by multiplying by the same as above) and the process returns to the original flow. If the upper limit value UC is not exceeded, proceed to step 147 and judge whether it is less than the lower limit value LC. If the judgment is YES, a coefficient k4 (=- 5.0, the same), and then calculate the corrected end time T2 and move to the original flow.

If it is above the lower limit here, the predicted tea leaf temperature CH
is within the allowable range, so the set end time
T1 transitions to the original flow without being modified.

With the above steps, the determination/correction process ends.

The allocation processing in steps 6, 12, and 17 is shown in FIG.

This process calculates the end moisture value A(t) of tea leaves when the moisture measurement has stabilized as described above, when the set value has been changed, and when the end time T1 has been corrected in the judgment/correction process. This is to allocate the target value to one-minute intervals. allocated 1
The target value for the minute interval is stored in a register, in actual operation. A medium rolling machine is used to adjust the moisture content of the tea leaves at one-minute intervals.

In step 171, the current time t is changed to the end time T1 (=
The required drying rate D is calculated by dividing the amount of moisture to be removed during that time [B(t) - A(T1)] by the remaining time (T1 - t) until T1, T2), and the current time is calculated in step 172. After adding 1, proceed to step 173.

In FIG. 3, steps 173 to 175 are the setting of the target moisture value A(t) for each minute until the end time (corrected end time) is reached, and the following step 176
-179 are preliminary settings in case the end moisture value is not achieved even though the end time has elapsed in the water extraction mode to be described later.

After that, the entire flow is repeated in the same way,
Eventually, the conditions for the judgment to become YES in step 20 or step 21 are satisfied, that is, the end moisture value A (T1) or the end time
When T1 (=T1, T2) is reached, the drying process is completed.

In the above process, waiting for the moisture measurement to stabilize (step 10) is because the introduced tea leaves are not sufficiently loosened at the beginning of the rolling process, and the moisture content is not uniform throughout the tea leaves. This is to avoid periods of instability where the detected moisture value fluctuates greatly.

In the actual control (step 18), the current moisture value B(t) is adjusted to the target moisture value A(t) set at one-minute intervals as described above, based on the detected values from various sensors and moisture measuring devices. This is achieved by controlling the blower fan and heating burner to match the temperature, and also controls to maintain the normal operation of the medium kneading machine, such as displaying data related to the operation and the number of rotations of the kneading drum.

As for the extraction mode (step 19), it is possible to select between water extraction mode and time extraction mode.
In the moisture extraction mode, the moisture in the tea leaves ends at moisture value A.
(T1), which may be slightly before or after the set end time T1 or T2, and the time extraction mode ends the process when the currently set end time is reached. The moisture value of the tea leaves taken out is slightly around the set end moisture value.

As described above, once the drying process starts, the current temperature (t) of the tea leaves is successively monitored to see if it is within the allowable range, and if it is outside the range, the set end time T1 is revised to the end time T2. Make corrections to keep the tea leaf temperature within an acceptable range and continue with the subsequent steps.

In the end, the input tea leaves are processed at the drying speed DA indicated by the E-L line as shown in Figure 5, and if the time extraction mode is selected, the process ends at time T1 or T2, and the water extraction mode is selected. If so, the moisture process ends at moisture value A (T1).

In this case, the actual moisture value will depend on the control ability of the medium rolling machine, the responsiveness of the tea leaves, etc.
Since it changes with the width shown by the hatching around DA, in the time extraction mode, for example, an error of △A (T2) may occur at the corrected end time T2, and in the water extraction mode, an error of △A (T2) may occur at the end time. An error of △T2 may occur.

In the first embodiment, the determination that the condition has been stabilized is determined not only by the passage of a set time as in this embodiment, but also by adding the satisfaction of various conditions as necessary. The time required for stabilization may be 3 minutes or more.

The allowable range (37° to 33°C) indicated by the upper limit UC and lower limit LC of tea leaf temperature is based on the average value obtained by processing a large number of tea leaf temperature data obtained from medium rolling machines at actual tea factories. It is obtained by adding or subtracting twice the deviation value, and it matches well with the actual condition of tea leaves during the rolling process.

This range is also suitable in terms of drying speed and for efficiently producing tea of good quality.

Note that the temperature range of the tea leaf temperature can be set in various other ways. For example, there is a method in which the average value of the actual tea leaf temperature in the previous batch process or the past several batches of the medium rolling process is stored, and that value is used as the upper limit temperature UC and lower limit temperature LC for judgment, or the method described above There are methods such as preparing values for each tea period, first tea and second tea, or changing values for each tea factory, allowing each factory to produce tea with characteristics.

In addition, when manufacturing tea with priority given to quality over quantity in order to obtain a high-quality product, the permissible range of the tea leaf temperature may be set narrowly, or set to a low value such as 33° to 35°C. Sometimes.

Various methods other than those described above can be used to determine whether the tea leaf temperature is outside the allowable range. For example, without using the predicted tea leaf temperature CH, only the current tea leaf temperature C(t) is used as an index, and it is monitored whether this value is out of the allowable range. In addition, in reality, the drying speed is inappropriate and the tea leaf temperature increases in most cases, and the tea leaf temperature rarely falls below the human skin temperature. Only the value may be specified. Moreover, instead of the permissible range of tea leaf temperature, a constant target value may be adopted.

In the above embodiment, the modification end time T2 is set in steps.
146 and 148, but the calculation formula used here is that the coefficient k3,
The value multiplied by k4 is added to the original end time. In addition to this, the calculation formula for the modified end time T2 can be calculated in various ways. For example, the corrected end time T2 is calculated by adding to the current time t the required processing time obtained by dividing the required removal moisture value of tea leaves (current moisture value - end moisture value) by a predetermined appropriate drying speed DA'. Also good.

T2 = t + [B(t) - A (T1] / DA') The above calculation formula completely ignores the operator's set value when the tea leaf temperature is out of the allowable range, and the appropriate drying at that point is performed. Modified end time based on speed DA′
This is an attempt to find T2.

Coefficients k1 to k4 and step 143 using them,
The calculation formulas in steps 146 and 148 are determined experimentally by processing a large amount of data obtained from the actual tea manufacturing process to suit the actual situation.

Next, as a second example, a case where a plurality of drying steps are set in the medium rolling step will be described.

Specifically, the middle rolling process is divided into two processes: the first half (first process) and the second half (second process), and the initial hot air temperature, spindle rotation speed, rolling drum rotation speed, and coefficient are set for each.
Values such as k1 to k4 are set, and each end moisture value A (T11), A (T12), end time T1,
T12 is set by the operator. In both the first step and the second step, the same processing as the flow used in the first embodiment is performed, but there are some differences. That is, even if a predetermined process is obtained in the first step and the process ends, the tea leaves are not taken out and the process directly proceeds to the second step.

Then, in the second step, new set values are read and predetermined processing is similarly performed. However, in step 10, the judgment as to whether the moisture measurement is stable is YES, so the processing is performed continuously without waiting, and the moisture extraction or time extraction is performed in the same way as in the first embodiment. The tea leaves are taken out and the process is finished.

Note that the end time T11 of the first process may shift back or forth as described above depending on the water extraction settings and judgment/correction processing, but the start time of the second process does not need to be fixed. From there, there is no problem.

Note that the upper limit value UC, lower limit value LC, and coefficients k1 to k4 of the current temperature C(t) of the tea leaves may be different between the first step and the second step.

As a third embodiment, the judgment/correction process may be performed for the first time at an undefined time t in the middle of the drying process.

In this case, the medium kneading machine is operated in a so-called sequence operation with the initial value set until time t, or feedback control is performed in which the operator's set value is directly used as the assigned target value.

As an example, we have described the drying process set in a medium rolling machine, but in the tea manufacturing process, the drying process is set for each rolling process of rough rolling, medium rolling, and fine rolling.
The present invention can be applied to any or more of these.

The present invention can also be applied by setting the entire tea manufacturing process starting with steaming heat and ending with final drying as one drying process, or by appropriately dividing the entire tea manufacturing process and setting one division as one drying process. You can also.

Furthermore, in these drying processes, the end time T1 set by the operator is stored in another register, and this time can be retrieved in the time retrieval mode.
It is also possible to specify T1. In this case, the ending moisture value is B(T1) as shown in Figure 5.
This may result in a large error from the final moisture value A (T1), but since the temperature of the tea leaves has been maintained within the permissible range until then, it will not have a negative effect on the quality of the tea, and the excess moisture will not be affected. This is a meaningful treatment considering that the water will be absorbed in the next process.

Effects of the Invention In the drying step of the tea manufacturing process, which is performed by setting the end moisture value and end time by the operator, the temperature of the tea leaves is always maintained within the permissible range, so that high quality tea can always be obtained.

[Brief explanation of the drawing]

Figure 1 is a chart of the main flow of the drying process.
Figure 2 is a flowchart of the judgment/correction process;
The figure is a flowchart of the allocation process, FIG. 4 is a diagram for explaining the drying rate, and FIG. 5 is a diagram for explaining the process according to another configuration example.

Claims (1)

[Claims] 1. Set end moisture value A (T1) and end time
In the drying process of the tea manufacturing process, which is carried out along the drying rate curve determined from T1, the current temperature C(t) of the tea leaves is measured, and if the tea leaf temperature deviates from the allowable range or is predicted to deviate in the future, Setting end time T1
A tea manufacturing method characterized by correcting the end time T2 and maintaining the tea leaf temperature within an allowable range. 2 Predicted tea leaf temperature CH based on current temperature C(t)
If the predicted tea leaf temperature CH is outside the allowable range that has a predetermined upper limit value UC and lower limit value LC regarding the tea leaf temperature, the set end time T1 is corrected to the corrected end time T2, and the tea leaf temperature is 2. The tea manufacturing method according to claim 1, wherein the tea production method is maintained within an allowable range. 3 Along with the current temperature C(t) of the tea leaves, the current moisture value B
(t), and the above-mentioned corrected end time T2 is calculated by dividing the current time t by the required removal moisture value of tea leaves (current moisture value - end moisture value) by a predetermined appropriate drying speed. The tea manufacturing method according to claim 1, further comprising processing time. 4. The tea manufacturing method according to any one of claims 1 to 3, characterized in that the drying step is terminated when the moisture content of the tea leaves reaches a predetermined moisture value A (T1). 5. The tea manufacturing method according to any one of claims 1 to 3, characterized in that the drying step is ended when the corrected end time T2 is reached. 6. The tea manufacturing method according to any one of claims 1 to 3, characterized in that the moisture management step ends when an initially set end time T1 is reached.