JPH0531929B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for accurately measuring the amount of tea leaves continuously supplied to a tea making machine, that is, the flow rate per unit time. In particular, the present applicant has filed a divisional application for what is covered in Japanese Patent Application No. 59-95378, which has already been filed.

[Prior art]

Regardless of variations in density due to the size of tea leaves, new leaves, old leaves, etc., constantly supplying a constant weight of fresh tea leaves to a fluidized tea machine such as a steamer is the key to high quality. This is extremely important in producing tea leaves.

Therefore, several devices have been devised to continuously supply a constant weight of tea leaves.

What can be seen in Japanese Patent Application Laid-Open No. 53-107495 is that a measuring drum rotated at a constant speed by a separate drive motor and supported by a spring is provided on the discharge side of a transfer conveyor, and a displacement detector is installed on the measuring drum. , the weight of the green tea leaves on the measuring drum is detected, and based on this detected amount, the circulating speed of the forward transfer conveyor is controlled so as to correct the weight of the green tea leaves sent to the measuring drum to a set value. Also, JP-A-55-96425
In the device disclosed in the publication, a feed controller frame is supported by a spring on a support arm that protrudes laterally from above the machine frame of the leaf feeder, the weight of green tea leaves on the frame is detected, and the weight of the green tea leaves on the frame is detected, and the weight of the green tea leaves on the frame is detected. This is to control the circulation speed of the conveyor belt that circulates through the frame and the conveyor belt of the main leaf feeder.

[Problem that the invention seeks to solve]

These devices detect the current flow rate of tea leaves and control the conveyance speed of a transporter based on this detected value to obtain the target flow rate of tea leaves. It is necessary to accurately detect the current flow rate of tea leaves.

However, in the conventional device as disclosed in the above-mentioned publication, the part that measures the current flow rate (corresponding to the measuring drum in the former, the feed controller frame in the latter) is connected to the feeder part that supplies tea leaves (corresponds to the feeding controller frame in the former). This corresponds to the conveyor, and in the case of the latter, the leaf feeder itself)
Since the weight is detected while receiving and discharging tea leaves, it is affected by vibrations that occur when receiving tea leaves, variations in the supply speed from the feeder, etc.
It was impossible to accurately detect the current flow rate.

In addition, in conventional methods and devices, it is necessary to divide the device into two parts, a metering part and a supply feeder part, and two drive motors are indispensable for driving each part. This meant larger sizes and higher manufacturing costs.

Therefore, the present invention provides a method and device for accurately measuring the actual flow rate of tea leaves using a relatively small and inexpensive device, without being affected by unintentional vibrations, etc. The purpose is to

[Means for solving problems]

In order to achieve the above object, the method of the present invention includes:
In front of the weighing conveyor, a transporter with a transport capacity superior to that of the weighing conveyor is installed, and this transporter is driven to feed the tea leaves almost constantly into the hopper section of the weighing conveyor. When the weight of the entire weighing conveyor reaches the upper value, the transporter is stopped while the weighing conveyor continues to be driven, and when the weight reaches the lower value, the transporter is driven again. The check time Xi (i=1, 2,
3...n), the current weight Yi of the entire weighing conveyor
The data obtained during this time (X ₁ , Y ₁ )
(X ₂ , Y ₂ )...(Xn, Yn) is processed by the least squares method, A and B are calculated to approximate the weight reduction transition to the formula Y = AX + B, and the value of A is calculated during this time. The apparatus of the present invention is characterized in that a measuring frame is supported on a supporting frame so as to be movable up and down, and a displacement detector is provided between the supporting frame and the measuring frame. A conveyor belt equipped with a hopper driven by a drive motor is installed on the weighing frame, and an upper value setter and a lower value setter are provided for the displacement detector, and the displacement detector is set to an upper value. It has an electric control circuit that can stop the forward transport plane when it reaches a lower value, drive it again when it reaches a lower value, sample the indicated value of the displacement detector during that time, and find the fluctuation rate during this time using the least squares method. It is characterized by

[Effect]

Next, the effect when the method of the present invention is implemented using the apparatus of the present invention will be explained.

First, the upper and lower values of the displacement detector are set by an upper value setter and a lower value setter, respectively, and then the weighing conveyor is driven.

When the transport machine is driven and tea leaves are started to be fed into the hopper of the conveyor belt, the tea leaves are continuously discharged from the end of the conveyor belt, but the transport capacity of the transport machine is greater than the transport capacity of the conveyor belt. Since the balance is high, tea leaves gradually accumulate in the hopper, and eventually the weight of the entire weighing frame reaches the upper value set by the upper setting device.

Then, the electric control circuit stops the conveyor while the conveyor belt continues to drive, and the weight of the entire weighing frame gradually decreases as the tea leaves are discharged by the conveyor belt. , samples the indicated value of the displacement detector.

In other words, check time Xi (i=1, 2, 3...
...n), the current weight Yi of the entire weighing conveyor is measured, and the electric control circuit also calculates the data (X ₁ , Y ₁ ) (X ₂ , Y ₂ )...
(Xn, Yn) is processed by the least squares method, and A, B
Calculate.

In the present invention, the value of A is the flow rate of tea leaves per unit time during this period.
This device continuously discharges a constant flow of tea leaves.

〔Example〕

Next, by measuring the current flow rate using the method and device for measuring the tea leaf flow rate of the present invention, and correcting the speed of the transfer conveyor based on the measured value, an attempt is made to supply tea leaves at the target flow rate to the tea machine. In this case, the structure and usage of the device will be explained below.

Reference numeral 1 denotes a vertical conveyor which is simply a transporter, and the transporter 1 is one whose transporting capacity is sufficiently larger than that of the steamer 2.

3 is a constant weight feeding device using the tea leaf flow measuring device of the present invention, 4 is a support frame, 5 is a measuring frame,
The weighing frame 5 is supported by the support frame 4 by four-bar parallel links.

The four-section parallel link has one end of the levers 6, 6 pivoted to the support frame 4, the other end pivoted to the central column 5' of the weighing frame 5, and a balance rod 8 pivoted to the pivot shaft 7. A weight 9 is movably attached to the rod 8 and can be moved up and down in balance with the weight of the measuring frame 5 and the like.

The weighing frame 5 is tilted upward from the starting end to the ending end, and rolls 10 and 11 are attached to both ends of the weighing frame 5. A conveyor belt 13 with a large number of crosspieces protruding between both the rolls 10 and 11 is installed, and a hopper is installed at the starting end. 14,
A variable speed drive motor 15 for driving the rolls 10 is installed on the front column 5'', and a scraping hand 16 which is rotated at the same time is installed above the transport surface of the conveyor belt 13, and these constitute a weighing conveyor 17.

Reference numeral 12 denotes a weighing frame 5 and a support frame 4 that expand and contract under the weight of tea leaves when the tea leaves are fed into the weighing conveyor 17.
This is a metering spring inserted between the

Reference numeral 18 denotes a displacement detector provided between the measuring frame 5 and the support frame 4, and a potentiometer 21 with a rack 19 mounted on the measuring frame 5 and a pinion 20 that meshes with the rack 19 attached to the support frame 4. It will be fixed.

Reference numeral 22 denotes a control box, and its front panel 23 includes a tea leaf flow rate setting device 24 for setting the desired tea leaf flow rate as the initial rotation speed of the drive motor 15, a tea leaf flow rate setting device 24 for setting the measuring range of the weighing conveyor 17, and a tea leaf flow rate setting device 24 for setting the desired tea leaf flow rate as the initial rotation speed of the drive motor 15, and for setting the measuring range of the measuring conveyor 17.
There are an upper value setter 25 and a lower value setter 26 of the displacement detector 18, which serve as indicators for control switching between drive and stop, a current tea leaf flow rate indicator 27, a cumulative flow rate indicator 28, etc. It has an electric control circuit 29 and the like.

Although the scale on the front panel 23 of the tea leaf flow rate setting device 24 is displayed as (Kg/h), it actually shows the relationship between the scale flow rate (Kg/h) and the rotation speed (rpm) of the drive motor 15. It is assumed that the initial rotation speed (rpm) of the drive motor 15 is set practically by determining it practically using the most standard tea leaves.

FIG. 5 shows an example of the block configuration of the electric control circuit 29. In the figure, CPU is a central processing unit,
EPROM is a read-only memory that can be erased and written, and contains control programs, arithmetic programs, etc. for processing. RAM is a random access memory that can be written to and read from a predetermined address, and uses the least squares method from the measured input data to determine the relational formula for determining the flow rate and the standard drive motor for the set flow rate. A large number of conversion formulas and the like are written for changing the rotation speed of the drive motor that drives the conveyor belt of the weighing conveyor based on the initial rotation speed table and the determined flow rate.

30 is an input/output port. 31 is an operation start switch, 32 is an operation stop switch, 33 is a measurement reset switch, 25 is the above-mentioned upper value setter, 26 is the same lower value setter, 18 is a displacement detector, 24 is a flow rate setter, and , these switches 31, 32, 33, setting devices 24, 25, 26,
The detector 18 is connected to gate circuits 35, 35, . . . controlled by a gate latch control circuit 34.
It is connected to the input/output port 30 via. Further, 15 is the aforementioned drive motor, 36 is the belt drive motor of the vertical conveyor 1, and these are relays.
It is connected to the input/output port 30 via RL, RL and latch circuits 37, 37, . . . controlled by the gate latch control circuit 34.

Reference numeral 38 denotes a vibrating gutter having a sufficient transport capacity to supply the tea leaves discharged from the weighing conveyor 17 one after another to the steamer 2. The vibrating gutter 38 is supported by a leaf spring 39 on the front frame 4' of the support frame 4 and driven by an eccentric drive mechanism 40.

The purpose of providing this vibrating gutter 38 is that if the weighing conveyor 17 is directly connected to the steamer 2, the steam flowing back from the input port of the steamer 2 will cause rust and adversely affect the weighing mechanism. It is.

Example of the method Next, a method for measuring the flow rate of tea leaves using the constant weight feeder of this example will be explained, and then, although it is a little extra, the following will be explained.
A method for supplying a constant weight of tea leaves using the apparatus of this embodiment will be explained.

First, the upper value and lower value of the displacement detector 18 are set in the upper value setting device 25 and the lower value setting device 26. The weight of the weighing conveyor 17 itself is balanced by the weight 9, so the upper value is 4.5 kg and the lower value is 1.0 kg.
Set it like this.

Next, after turning on the operation start switch 31 and starting the steamer 2, weighing conveyor 17, and vibrating gutter 38, the flow rate of tea leaves is determined in consideration of the processing capacity of the steamer 2, the amount of steam, the degree of steaming, etc. Surface panel 23
Set the upper tea leaf flow rate setting device 24 to that value.

Then, the optimum rotation speed (currently this
Rrpm) is referenced on the RAM, and the value is output from the electric control circuit 29 to the drive motor 15, and the conveyor belt 13 of the weighing conveyor 17 moves the drive motor 15 at a constant speed (rpm) when the number of revolutions is Rrpm. V).

Next, turn on the main switch for vertical conveyor 1,
The vertical conveyor 1 is driven to feed green tea leaves into the hopper 14 of the weighing conveyor 17.

On the weighing conveyor 17 side, the conveyor belt 13
is circulating at a constant speed V, so the green tea leaves received by the hopper 14 are sent one after another from the end to the vibrating gutter 38.
However, since the vertical conveyor 1 has a sufficiently large transportation capacity, green tea leaves eventually accumulate in the hopper 14.

Then, due to the increase in the number of green tea leaves, weighing conveyor 1
As the weight of the entire measuring frame 7 increases, the measuring frame 5 gradually descends, and the rack 19 of the displacement detector 18 rotates the pinion 20 on the support frame 4 side, which rotates the shaft of the potentiometer 21, so that the indicated value is It's changing.

Then, when 4.5 kg of green tea leaves are accumulated on the weighing conveyor 17 and reaches the value set by the upper setting device 25, the electric control circuit 29 issues a stop command to the vertical conveyor 1, and the displacement detector 1
Sampling of the indicated value of 8 begins.

Even after the vertical conveyor 1 stops, the weighing conveyor 17 and the conveyor belt 13 continue to circulate at the same speed V to discharge the accumulated green tea leaves, so that the whole weighing conveyor 17 gradually becomes lighter as the number of green tea leaves decreases.

To explain the weight change of the entire weighing conveyor 17 during this period with reference to FIG. 3, in the section (a), the vertical conveyor 1 and the conveyor belt 13 of the weighing conveyor 17 are both driven, and the weighing conveyor 17 performs receiving and discharging. However, in the input accumulation section where the weight of the entire weighing conveyor 17 increases, the vertical conveyor 1 is stopped in the section (b), and only the conveyor belt 13 of the weighing conveyor 17 is driven, and the weighing conveyor 17
shows a discharge reduction section in which only discharge is performed and the weight of the weighing conveyor 17 as a whole decreases.

In the figure, a curve α shows the weight increase of the entire weighing conveyor 17 when only the vertical conveyor 1 is driven, and a curve β shows the weight decrease when it is assumed that only the conveyor belt 13 of the weighing conveyor 17 is driven. .

Therefore, weighing conveyor 17 in section (a)
The overall "actual weight change" follows a curve obtained by subtracting the beta curve from the alpha curve (ao to bo).

Since the "actual weight change" of the entire weighing conveyor 17 in section (b) changes with substantially the same slope as the β curve, it follows the (bo~a ₁ ) curve.

The reason why the curves α and β are not straight lines but curves is because even if the drive motors 15 and 36 are driven at a constant rotation speed, the amount scooped into the bucket and the thickness of the tea leaves on the belt are not constant. This happens because of this. In addition, due to the vertical vibration of the weighing frame 5, the indicated value of the displacement detector 18 does not necessarily change (ao
~bo) (bo~ _a1 ) It does not necessarily indicate the value on the curve.

Therefore, in the present invention, the transition of the indicated value of the displacement detector 18 in the emission reduction section (b) is sampled.

In other words, sampling involves reading the measurement time of this weight reduction transition and the indicated value of the displacement detector at that time into the working area of the RAM every moment until the weight of the entire weighing conveyor 17 reaches from the upper value to the lower value. It is.

Note that in this embodiment, this sampling is programmed to occur every second, so
If Yi is the indicated value of the displacement detector, (1, Y ₁ )
It is read into the RAM as data (2, Y ₂ ) (3, Y ₃ )...(N, Yn).

Then, as soon as the weight of the entire weighing conveyor 17 reaches a lower value, the least squares method is applied to these data that have been read so far, and the emission reduction section is determined.
The values of A and B are calculated in order to approximate the weight reduction transition in (b) to the straight line of Y=AX+B.

This calculation is performed as follows.

That is, if the coordinates of the i-th data are (Xi, Yi) in the X-Y coordinates of Figure 4, then Error=Yi-(Ai+B) - Now, if the residual sum of squares is ξ, then ξ=i- (AXi+B)} ² =Σ{Yi ² −2Yi(AXi+B)
+(AXi+B) ² }=Σ{Yi ² −2AXiYi−2BYi+
A ² Xi ² +2ABXi+B ² } Here, finding A and B that minimize ξ is effective as an approximate expression.

For this purpose, A and B are obtained by combining 〓ξ/〓A=0 and 〓ξ/〓B=0.

〓ξ／〓Ａ＝Σ｛−2XiYi＋2AXi ² ＋2BXi｝…… 〓ξ／〓Ｂ＝Σ｛−2Yi＋2AXi＋2B｝ …… よりAΣXi ² ＋BΣXi＝ΣXiYi ……′ よりAΣXi＋ΣB＝ΣYi ……′ ′と′よりＡ＝ It is easier to see if expressed as nAΣXiYi−ΣXiΣYi/nΣXi ² −(ΣXi) ² [XY]=ΣXiYi, [X]=ΣXi, [Y]=ΣYi.

A=n[XY]-[X][Y]/n[X ² ]-[X] ² X: Time (seconds) Measured every second Y: Potentiometer A/D value n: Number of measured data (current , which corresponds to the number of seconds after the start of measurement).

In addition, although the check time for sampling was set to 1 second in this embodiment, it is not limited to this.
It is not necessarily necessary to sample at regular intervals.

The point is that it is sufficient to be able to sample an appropriate number of data for processing using the least squares method.

This value of A is the approximate rate of change of the weight reduction transition in the discharge reduction section (b), and can be regarded as the flow rate per unit time during this period, so this value is displayed and output to the flow rate display 27 as the flow rate of tea leaves. do.

The above is the explanation of the flow rate measuring method of the present invention in this embodiment, and then the constant weight supply method of this embodiment will be further explained.

That is, when the entire weighing conveyor 17 reaches the value set by the lower value setter 26, data sampling is immediately interrupted, and the above-mentioned A is determined based on this data. , a speed change command is issued from the electric control circuit 29 to the drive motor 15 driving the conveyor belt 13 of the weighing conveyor 17 so that its rotational speed becomes R×Q/A (R ₁ rpm).

On the other hand, at approximately the same time, the vertical conveyor 1 is driven again, and the weighing conveyor 17 performs feeding and discharging at the same time, and then the loading/accumulating section (a) begins. /A, so the circulation speed of the conveyor belt 13 changes to V×Q/A.

Then, when the weight of the entire weighing conveyor 17 reaches the upper value, the vertical conveyor 1 is stopped again, only the conveyor belt 13 of the weighing conveyor 17 is driven, and the discharge reduction section (b) begins. and,
Again, weighing conveyor weight loss data (1,
As soon as Y ₁ ) ₂ (2, Y ₂ ) ₂ (3, Y ₃ ) ₂ ... (n, Yn) ₂ is read and the weight of the entire weighing conveyor reaches the lower value, these data are calculated using the least squares method. The value of A (this value of A is different from the previous value of A, so if the previous value is A ₁ , this value of A is expressed as A ₂ ). ) is displayed and the rotation speed of the drive motor 15 that drives the conveyor belt 13 of the weighing conveyor 17 is R ₁ ×
Q/A ₂ is corrected, and this is repeated each time the weight of the entire weighing conveyor 17 reaches the lower value.

To explain this using Fig. 3, from start to k
Data (1, Y ₁ ) k for the th emission reduction section (b)
(2, Y ₂ ) k (3, Y ₃ ) k ... (N, Yn) k data is sampled and the k-th interval ( The actual flow rate in (a) and (b) is indicated as Ak, and the circulating speed of the conveyor belt 13 of the weighing conveyor 17 in the (k+1)th section (a) and (b) is expressed as the rotation speed of the drive motor 15.
By correcting Rk x Q/A _k+1 , the set flow rate Q Kg/h of tea leaves is corrected to flow steadily, and this is repeated every time the weight of the entire weighing conveyor 17 reaches the lower value. .

On the other hand, since the vibrating gutter 38 sends out the green tea leaves transferred from the weighing conveyor 17 one after another without stagnation, it is possible to constantly supply a constant weight of green tea leaves to the next steamer 2 with considerable accuracy.

The drive motor 15 may be a so-called variable speed motor as in this embodiment, or a general-purpose motor may be controlled by an inverter to control the rotation speed, or the shaft of the general-purpose motor may have a variable diameter. Of course, the present invention can also be applied in the same way even if the pulley is attached to the shaft and the speed is changed by moving the motor base.

Furthermore, in the embodiment, the circulating speed of the conveyor belt 13 of the metering conveyor 17 is always corrected by the previous circulating speed, but the present invention is not limited to this. For example, it may be simply changed to R×Q/A _k or it may be averaged to R×2Q/(A _k-1 +A _k ).

In short, it is sufficient to provide a correction formula so that the actual flow rate quickly converges to the set flow rate.

In addition, in this example, an apparatus was described that uses the method and apparatus for measuring the flow rate of tea leaves of the present invention to constantly supply tea leaves at a target flow rate to a tea making machine, but the use of the present invention is limited to this. For example, it can be used as a means to accurately measure the current flow rate of tea leaves when making tea processing elements respond to changes in the flow rate of supplied tea leaves, or it can also be used simply as a means to calculate the cumulative flow rate. It is possible.

〔Effect of the invention〕

According to the method for measuring the flow rate of tea leaves of the present invention, when measuring the entire weight of the weighing conveyor, the reception of tea leaves from the transportation machine in front of the weighing conveyor is stopped. Measured values are obtained that are completely unaffected by variations in the supply speed of the transporter, and the flow rate of tea leaves per unit time is constant from the time when the weight of the entire weighing conveyor reaches the upper value until it reaches the lower value. During check time
Data (X ₁ ,
Y ₁ ) (X ₂ , Y ₂ )...(Xn, Yn) is processed using the least squares method, and the weight loss transition is determined by the value of A when it approximates the formula Y = AX + B So,
Extremely accurate flow rates can be determined.

In addition, since the transport aircraft in front only needs to be controlled on and off, conventional equipment such as vertical buckets can be used as is, and there is no need for large-scale rearrangement of equipment or special linkage control, making it extremely Full of flexibility.

Further, according to the tea leaf flow rate measuring device of the present invention,
There is no need to install a feeder section in front of the measuring section, which is required in the conventional system, so only one drive motor is required, and the whole system is compact and can be manufactured at low cost, so it can be easily integrated into existing tea manufacturing lines. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a front view of one embodiment of the present invention apparatus including front and rear equipment, Fig. 2 is a front panel view of the control box, and Fig. 3 is an explanatory diagram for explaining weight changes and conditions of the weighing conveyor. FIG. 4 is an explanatory diagram for explaining the flow rate measurement method, and FIG. 5 is a block diagram of the electric control circuit. 1... Vertical conveyor, 3... Constant weight feeding device,
4... Support frame, 5... Measuring frame, 13... Conveyor belt, 14... Hopper, 15... Drive motor, 17... Weighing conveyor, 18... Displacement detector, 24... Flow rate setting device, 25 ...Upper value setter, 26...Lower value setter, 29...Electric control circuit.

Claims (1)

[Scope of Claims] 1. A transporter having a transport capacity superior to that of the weighing conveyor is disposed in front of the weighing conveyor, and this transporter is driven to feed the tea leaves into the hopper section of the weighing conveyor almost constantly, while weighing the tea leaves. The conveyor is driven to continuously discharge the input tea leaves from the terminal end, and when the weight of the entire weighing conveyor reaches the upper value, the transporter is stopped while the weighing conveyor is still being driven, and when the weight reaches the lower value, it is restarted. A check time Xi (i=1,
2, 3...n) The current weight of the entire weighing conveyor
Yi is measured and the data obtained during this period (X ₁ , Y ₁ )
(X ₂ , Y ₂ )...(Xn, Yn) is processed by the least squares method, A and B are calculated to approximate the weight reduction transition to the formula Y = AX + B, and the value of A is calculated during this time. A method for measuring the flow rate of tea leaves, which is the flow rate of tea leaves per unit time. 2. A weighing frame is supported on a support frame so as to be movable up and down, a displacement detector is provided between the support frame and the weighing frame, and a conveyor belt driven by a drive motor and equipped with a hopper is installed on the weighing frame, On the other hand, an upper value setter and a lower value setter are provided for the displacement detector, and furthermore, when the value of the displacement detector reaches the upper value, the forward transport machine is stopped, and when the value reaches the lower value, it is driven again, and the A tea leaf flow measuring device that has an electric control circuit that can sample the indicated value of a displacement detector and find the rate of variation during this time using the least squares method.