JPS6244898B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a constant weight feeding method and apparatus for continuously feeding tea leaves at a target flow rate to a tea manufacturing process.

Background technology and problems Continuously supplying a constant weight of fresh tea leaves to a steamer is expensive, regardless of weight fluctuations due to differences in size, new leaves, old leaves, etc. of fresh tea leaves picked in tea gardens. This is extremely important in producing quality tea leaves.

Several inventions have been made to continuously supply a constant weight of green tea leaves to a steamer.

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 the transfer conveyor, and a displacement detector provided on the measuring drum is used. , 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.

In the conventional systems disclosed in these publications, the measuring part (corresponding to the measuring drum in JP-A No. 53-107495, and the feeding controller frame in JP-A-55-96425) receives the green tea leaves. Since the weight is detected while the green tea leaves are being discharged, the feeding speed of the green tea leaves is known. (corresponding to the main body of the machine) is required.

In other words, in conventional methods and devices, the measuring section and the supply feeder section had to be divided into two parts, and two drive motors were indispensable for driving each part.

This meant an increase in the size of the equipment constituting it and an increase in manufacturing costs.

Purpose of the Invention The present invention measures the actual flow rate of tea leaves with high accuracy and corrects the current circulating speed of the conveyor belt based on this highly accurate value, thereby making it possible to continuously flow the set target flow rate. purpose.

SUMMARY OF THE INVENTION Therefore, in order to achieve the above object, the first invention disposes a transporter having a transport capacity superior to that of the weighing conveyor in front of the weighing conveyor, and drives the transporter to roughly collect the tea leaves. While constantly feeding the tea leaves into the hopper section of the weighing conveyor, the weighing conveyor is driven to discharge the introduced tea leaves from the terminal end, and when the weight of the entire weighing conveyor reaches the upper value, the weighing conveyor is driven. The transporter is stopped as it is, and the transporter is driven again when the weight reaches the lower value, and the check time Xi (i
= 1, 2, 3... n), the current weight Yi of the entire weighing conveyor is measured, and the data obtained during this time (X ₁ , Y ₁ ) (X ₂ , Y ₂ )... (X _o , Y _o ) using the least squares method, and calculate the weight reduction transition by Y=AX+B
A and B are calculated to approximate the formula, and when the weight of the entire weighing conveyor reaches the lower value, the circulating speed of the conveyor belt of the weighing conveyor is corrected based on the value of A. The second invention is characterized by a constant weight supply method of tea leaves, in which the flow is repeated every time the weight of the entire weighing conveyor reaches a lower value, so that the target flow rate flows. A conveyor belt driven by a drive motor and having a large number of projecting crosspieces is installed across both ends of the weighing frame, a hopper is installed at the starting end, and a displacement detection device is installed between the weighing frame and the support frame. On the other hand, the upper value setter, the lower value setter, the flow rate setter for setting the desired target flow rate of tea leaves as the rotation speed of the drive motor, and the displacement detector change from the upper value to the lower value. The indicated value of the displacement detector is sampled until the displacement occurs, the fluctuation rate during this period is determined by the least squares method, and the rotation speed of the drive motor is corrected by calculating this fluctuation rate and the set value of the flow rate setting device. It is also characterized by being a constant weight supply device for tea leaves, which has an electric control circuit that controls driving and stopping of the transportation machine in front.

Embodiment Next, after explaining the illustrated embodiment of the apparatus of the present invention, an example of the method of the present invention will be explained using the apparatus of the embodiment.

Embodiment 1 of the device 1 is a vertical conveyor that is simply a transport device for supplying green tea leaves to the constant weight feeding device of the present invention, and the conveyor 1 is one whose transport capacity is sufficiently larger than the processing capacity of the steamer 2. .

3 is a constant weight feeding device of the present invention, 4 is a support frame,
5 is a weighing frame, and 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. The weight 9 of the rod 8 is movably attached 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. The initial rotation speed (rpm) of the drive motor 15 is essentially determined by experimentally determining 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, calculation 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.

Embodiment of the Method The constant weight feeding device of the present invention is thus carried out as follows.

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 to something like Kg.

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 optimal rotation speed (this is now referred to as R rpm) for flowing the set flow rate, for example, standard tea leaves at QKg/h, is referenced on the RAM, and that value is output from the electric control circuit 29 to the drive motor 15. , the conveyor belt 13 of the weighing conveyor 17 starts circulating at a constant speed (this is designated as V) when the rotational speed of the drive motor 15 is Rrpm.

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 conveyor belt 13 of the weighing conveyor 17 continues to circulate at the same speed V to discharge the accumulated green tea leaves, so that the entire 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 time with reference to FIG. 3, in section A, the vertical conveyor 1 and the conveyor belt 13 of the weighing conveyor 17 are both driven, and while the weighing conveyor 17 is receiving and discharging, 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 (a ₀ to b ₀ ) obtained by subtracting the β curve from the α curve.

Since the "actual weight change" of the entire weighing conveyor 17 in section B changes at substantially the same slope as the β curve, it follows the (b ₀ -a ₁ ) curve.

The reason why the curves α and β are not straight lines but curves is because even if each drive motor is 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. Furthermore, due to the vertical vibration of the weighing frame 5, the indicated value of the displacement detector 18 does not necessarily change from (a ₀ to
b ₀ ) (b ₀ to a ₁ ) 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.

In addition, in this embodiment, this sampling is programmed to be performed every second, so
If Yi is the indicated value of the displacement detector, (1, Y ₁ )
The data (2, Y ₂ ) (3, Y ₃ )...(N, _Yo ) is read into the RAM.

When the weight of the entire weighing conveyor 17 reaches a lower value, the least squares method is immediately applied to these data read so far, and the weight reduction transition in the emission reduction section B is approximated to a straight line of Y = AX + B. In order to do so, the values of A and B are calculated.

This calculation is performed as follows.

In other words, if we set the coordinates of the i-th data as (Xi, Yi) in the X-Y coordinates of Figure 4, then Error=Yi-(AXi+B) - Now, if we set the residual sum of squares as ξ, then ξ=Σ{ Yi−(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, find A and B that minimize ξ. It is effective to obtain this as an approximate expression.

For this purpose, A and B are determined by simultaneously ∂ξ/∂A=0 and ∂ξ/∂B=0.

∂ξ/∂A=Σ{−2XiYi+2AXi ² +2BXi}… ∂ξ/∂B=Σ{−2Yi+2AXi+2B}… From AΣXi ² +BΣXi=ΣXiYi…′ AΣXi+ΣB=ΣYi…′ From ′ and ′, A=nΣXiYi− ΣXiΣYi/ nΣXi ² −(
ΣXi) ² [XY] = ΣXiYi, [X] = ΣXi, [Y] = ΣYi for easier viewing.

A=n[XY]-[X][Y]/n[ ^X2 ]-[X
] ² X: Time (seconds) Measured every second Y: Potentiometer A/D value n: Number of measurement data (corresponds to the number of seconds after the start of measurement) The value of A is determined by .

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 enough to sample an appropriate number of data to be processed by the least squares method.

The value of A is an approximate rate of variation 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 tea leaf flow rate.

Then, in the constant weight supply method of the present invention, the circulating speed of the conveyor belt 13 is changed based on the value of A.

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

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 the next input/accumulation section A begins.
Since this has been corrected, the circulation speed of the conveyor belt 13 has changed to V×Q/A.

When the weight of the entire weighing conveyor 17 eventually 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, Y _o ) ₂ is read and the weight of the entire weighing conveyor reaches the lower value, these data are changed to the minimum automatic value. Processed by multiplication, A of the Y = AX + B formula is found, and the value of A (this value of A is different from the previous 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, Y _o ) k data is sampled and the k-th interval is obtained by calculating Ak of the approximate formula Y=AX+B using the least squares method. The actual flow rates of A and B are expressed as Ak, and (k+1)
By correcting the circulating speed of the conveyor belt 13 of the weighing conveyor 17 in the sections A and B and the rotation speed of the drive motor 15 to Rk×Q/A _K+1 , tea leaves at a set flow rate of QKg/h can be maintained at a steady state. Modify it so that it flows,
This is repeated each time the weight of the entire weighing conveyor 17 reaches a 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, and for example, based on the initial rotation speed determined from the set flow rate. , may be simply changed to R×Q/ _AK , or may be averaged as R×2Q/( _AK-1 + _AK ).

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

Effects of the Invention As is clear from the above description, the first invention provides a transporter having a transport capacity superior to that of the weighing conveyor in front of the weighing conveyor, and drives the transporter to roughly collect the tea leaves. While constantly feeding the tea leaves into the hopper section of the weighing conveyor, the weighing conveyor is driven to discharge the introduced tea leaves from the terminal end, and when the weight of the entire weighing conveyor reaches the upper value, the weighing conveyor is driven. The transporter is stopped as it is, and when the lower value is reached, the transporter is driven again, and the check time is set from when the weight of the entire weighing conveyor reaches the upper value until it reaches the lower value.
The current weight Yi of the entire weighing conveyor is measured every Xi (i = 1, 2, 3...n), and the data obtained during this time (X ₁ , Y ₁ ) (X ₂ , Y ₂ )... (X _o , Y _o ) using the least squares method, and calculate the weight reduction transition as Y=
A and B are calculated to approximate the formula AX + B, and when the weight of the entire weighing conveyor reaches a lower value, the circulating speed of the conveyor belt of the weighing conveyor is corrected based on the value of A, This is repeated every time the weight of the entire weighing conveyor reaches a lower value, so that the target flow rate is made to flow.This second invention is characterized by a constant weight supply method of tea leaves. A conveyor belt driven by a drive motor and having a large number of projecting crosspieces is installed across both ends of the weighing frame supported on the frame, a hopper is installed at the starting end, and a conveyor belt is installed between the weighing frame and the support frame. is equipped with a displacement detector, and on the other hand, an upper value setter, a lower value setter, a flow rate setter for setting the desired target flow rate of tea leaves as the rotation speed of the drive motor, and a displacement detector are set from the upper value to the lower value setter of the displacement detector. Sample the indicated value of the displacement detector until it shifts to the lower value, find the fluctuation rate during this period by the least squares method, and calculate the fluctuation rate and the setting value of the flow rate setting device to determine the rotation speed of the drive motor. It is characterized by being a constant weight supply device for tea leaves, which has an electric control circuit that corrects the problem and controls the driving and stopping of the transportation machine in front.

Therefore, according to the present invention, unlike the conventional method of measuring while receiving and discharging tea leaves, there is no room for errors in the speed of the supply feeder section or the effects of vibrations during receiving of tea leaves to enter into the measured values. Since the current flow rate can be measured extremely accurately, a constant weight of tea leaves can be supplied at all times.

In addition, it is extremely flexible because it is sufficient to simply turn on and off the transport equipment in front of the vertical conveyor, and there is no need for large-scale rearrangement of equipment or special linkage control.

Furthermore, according to the device of the present invention, there is no need to provide a conventional supply feeder section in front of the measuring section.
Therefore, 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 an existing tea manufacturing line.

[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, 1
4...Hopper, 15...Drive motor, 17...Measuring conveyor, 18...Displacement detector, 24...Flow rate setting device,
25... Upper value setter, 26... Lower value setter, 29
...Electrical 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 the transporter is driven to almost constantly feed tea leaves into the hopper section of the weighing conveyor, When the weighing conveyor is driven and the input tea leaves are discharged from the end, and the weight of the entire weighing conveyor reaches the upper value, the weighing conveyor stops the transport machine while being driven, and when the weight reaches the lower value. The transporter is driven again, and the check time Xi (i=
1, 2, 3... n), the current weight Yi of the entire weighing conveyor is measured, and the data obtained during this time (X ₁ , Y ₁ ) (X ₂ , Y ₂ )... (X _o , _Yo ) is processed using the least squares method, and the weight reduction transition is calculated as Y=AX+B
A and B are calculated to approximate the formula, and when the weight of the entire weighing conveyor reaches the lower value, the circulating speed of the conveyor belt of the weighing conveyor is corrected based on the value of A. A constant weight supply method of tea leaves in which the target flow rate is achieved by repeating the following steps each time the weight of the entire weighing conveyor reaches a lower value. 2. A weighing frame supported vertically on a support frame has
A conveyor belt driven by a drive motor and having a large number of projecting crosspieces is installed across both ends, a hopper is installed at the starting end, a displacement detector is installed between the weighing frame and the support frame, and one , an upper value setter and a lower value setter of the displacement detector, a flow rate setter that sets the desired target flow rate of tea leaves as the rotation speed of the drive motor, and a period until the displacement detector is displaced from the upper value to the lower value. The indicated value of the displacement detector is sampled and the fluctuation rate during this period is determined by the least squares method, and this fluctuation rate and the setting value of the flow rate setting device are calculated to correct the rotation speed of the drive motor and to A tea leaf constant weight feeding device that has an electric control circuit that controls the drive and stop of the tea leaves.