JPH0277623A - Method and apparatus for weight type measurement of raw material consumption amount in extruder - Google Patents

Abstract

PURPOSE:To continuously and accurately measure the wt. consumption of a raw material by supplying the raw material so as to almost reach an upper limit predetermined amount at each time when the raw material in a hopper scale reaches a lower limit predetermined amount. CONSTITUTION:When all of devices are operated a gate 32 is opened by a gate driver 33 and the raw material in a storage tank 31 is passed through a hopper scale 20 to be supplied to an extruder 10. The flow rate of the raw material supplied from a raw material feeder 30 is made larger than that of the raw material supplied to the extruder 10 and the raw material forms an angle alpha of repose gradually in a cylindrical body 11 to be stagnated therein and the top of the raw material reaches the emitting port 23 of the scale 20 and the emission of the raw material from the scale 20 is stopped or becomes gentle. When the raw material is further stored in the scale 20 to exceed a lower limit wt. value to turn the output of a lower limit wt. value sensor OFF and the raw material is stored up to an upper limit wt. value at last, a load cell 21 shows an upper limit value and the gate 32 is closed by the driver 33. The bubble extruded from a molding die 13 is filled with air and grasped by pinch rollers 15 to be set to a predetermined diameter.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to an extrusion process in which thermoplastic synthetic resin pellets, recycled pulverized raw materials, or other raw materials in the form of flakes are melted and extruded to form blown films or extruded tubes. The present invention relates to a method and apparatus for continuously measuring the amount of raw material consumed by the extruder by weight during operation of the extruder.

(Prior art) Conventionally, in order to measure the discharge weight of molten resin from an extruder, a part of the molten resin during molding is removed per unit time and measured using a weighing scale, or the raw material of the extruder is A volume meter is installed in the supply section to measure the volume.

Alternatively, an upper limit level sensor is installed in the supply hopper of the extruder, and several batches of pre-measured raw materials are fed in batches at regular intervals until the raw materials reach the upper limit level sensor, and the consumption of raw materials is determined by the number of batches. The weight was being measured.

Furthermore, Japanese Patent Laid-Open No. 62-280020 discloses an extruder in which the hopper is supported by a weight scale.

(Problems to be Solved) Among the above-mentioned prior art techniques, in which the weight of molten resin extruded from an extruder is actually measured by cutting it during a certain period of time, the extrusion molding operation is interrupted.

Not only does the operating efficiency of the extruder drop significantly, but also the weight cannot be measured continuously during extrusion.

In addition, in the capacity measurement method and device, there is a difference in weight even if the capacity is the same due to differences in the size of the raw materials and the coefficient of friction on the surface, and it is necessary to compensate each time the resin material or raw material changes. Bridging may also occur within the container, and variations in filling rate may occur, making accurate weight measurement impossible in any case.

Furthermore, with the last batch-type weight measurement device and method, it is not possible to measure weight errors smaller than the weight unit of the batch, and only very approximate measurements can be made.

In addition, the above-mentioned patent publication states that the hopper of the extruder is supported by a weight scale, but the small diameter supply pipe extending downwards is fixedly connected to the extruder. Therefore, the weight of the hopper is also supported by the extruder.

There is no specific description of how the weight of the hopper is measured.

Therefore, the method and device of the present invention solves the above-mentioned drawbacks, and allows the consumption weight of raw materials to be continuously and accurately measured, regardless of the raw material material, size, or surface friction coefficient, and this can be displayed numerically. The purpose of this invention is to make it possible to more accurately estimate the current flow rate of discharged resin, and to provide such a method and apparatus on the market.

B6 Structure of the invention (means for solving the problem) In order to achieve the above object, when the raw material discharged from the discharge port of the open layer of the hopper scale is supplied into the supply hopper of the extruder, the extrusion The top of the raw material deposited at an angle of repose in the raw material reservoir forming the feed port of the machine reaches the discharge port of the hopper scale, and when this is closed, the amount of raw material in the feed hopper decreases. According to the method, the same amount of raw materials are sequentially discharged from the hopper scale.

Next, each time the raw material in the hopper scale reaches the lower limit predetermined amount, the raw material is supplied to approximately the upper limit predetermined amount, then the raw material supply to the hopper scale is stopped, and then the first
The secondary weight is measured, and then the secondary weight is measured after a predetermined time from the time when the primary weight was measured until the raw material in the hopper scale reaches the lower limit predetermined amount.

Finally, the raw material discharge weight per unit time is calculated based on the difference between the primary weight value and the secondary weight value and the predetermined time, and this is digitally displayed.

The above method is a gravimetric measurement method for raw material consumption in an extruder.

Moreover, in order to achieve the above-mentioned object, in the gravimetric measurement method of raw material consumption in an extruder, the predetermined time may be set to 36 seconds.

In addition, in order to achieve the above object, a load cell-type hopper scale, which is equipped with an umbrella-shaped baffle plate above the discharge port near the discharge port and serves as a constantly open discharge port, is stacked on top of the raw material reservoir of the extruder. The discharge port of the hopper scale is located within the raw material reservoir, and the spout of the hopper scale is sized to be able to discharge a flow rate larger than the raw material consumption flow rate of the extruder. is equipped with a raw material supply device with an opening/closing gate, the supply of the raw material is started by the output signal of the raw material lower limit amount sensor in the hopper scale, and the raw material supply is started by the output signal of the raw material upper limit amount sensor in the hopper scale. is provided with a raw material supply drive device that stops the hopper scale, and a measuring device that measures the weight of the hopper scale by the distortion of the load cell twice after the raw material supply, immediately after the gate is closed, and after a predetermined time; A gravimetric measuring device for raw material consumption in an extruder, comprising: a calculation device that calculates the raw material consumption per unit time based on the weight value difference and the predetermined time; and a display device that digitally displays the calculation result. shall be.

Furthermore, in order to achieve the above object, in a gravimetric measuring device for raw material consumption in an extruder, the extruder is any extruder equipped with several extruders for molding a single molded product. In some cases.

In order to achieve the above-mentioned object, the upper and lower limit quantity sensors of the raw material in the hopper scale are upper and lower limit weight value sensors that issue output signals when the strain value of the load cell indicates an upper or lower limit value. In some cases, it is a gravimetric measuring device for weight consumption, which is characterized by:

Further, in order to achieve the above-mentioned object, there may be a gravimetric measuring device for weight consumption, characterized in that the upper and lower limit amount sensors of the raw material in the hopper scale are bulk sensors provided in the hopper scale.

Further, in order to achieve the above object, a second opening/closing gate is provided at the discharge port of the supply hopper, and the second opening/closing gate is closed by the output signal of the lower limit sensor and opens after the gate of the raw material supply device is closed. The weight due to distortion of the load cell immediately after closing the opening/closing gate and the strain of the load cell of the leaper after closing the gate of the supply device until the second opening/closing gate opens are measured, and from the difference between these values, it is determined that the amount of material supplied to the hopper scale is It may also be characterized in that it has a function of calculating the supply amount each time it is fed and sequentially accumulating it, and that the display device also displays the calculated weight and cumulative value.

(Function) Next, the specific invention of Claim 1 will be explained in detail together with the operation of the device invention of Claim 3.

When the extruder is heated to a predetermined temperature and a predetermined raw material is supplied from the supply device to the hopper scale, the raw material accumulated in the scale is fed into the raw material reservoir of the extruder through the discharge port, which is always open. The raw materials are sequentially conveyed by sequentially operating extruders, heated and melted during the process, and extruded as bubbles or tubes for inflation tubes from a molding die connected to the extruder.

The amount of raw material now fed to the hopper scale is greater than the amount of raw material consumed by the extruder.

The raw material that has fallen from the hopper scale into the raw material reservoir forms an angle of repose within the raw material reservoir, and when its top closes the discharge port of the hopper scale, the discharge amount of the raw material from the hopper scale and the raw material reservoir from the raw material reservoir are transferred to the extruder. A state is reached in which the amount of raw material consumed is exactly balanced.

In other words, the raw material in the hopper scale is not discharged into the raw material reservoir unless the raw material in the raw material reservoir is consumed.

The hopper scale is provided with two sensors, upper and lower limits, for detecting the weight or bulk of the raw material, and the gate of the raw material supply means on the hopper scale is opened by the supply drive means in response to the output signal of the lower limit quantity sensor. When the raw material is put into the hopper scale and the weight or bulk of the raw material reaches the upper limit quantity sensor position, the gate is closed again by the gate driving means in response to the output signal of the upper limit quantity sensor, and the supply of the raw material is stopped. .

Thereafter, the above operations are repeated in response to changes in the level of the raw material, regardless of whether or not the metering of the present invention is carried out.

Next, when measuring the amount of raw material consumed in the supply hopper, the raw material is fed into the hopper scale from the raw material supply device mentioned above, and the raw material is supplied until the upper limit amount sensor of the hopper scale issues an output signal, and then Immediately after the hopper scale is closed, the weight of the hopper scale is measured electrically using the strain of the load cell, and this weight is used as the first weight measurement.

Next, as the extruder operates, the raw materials in the supply hopper are sequentially fed into the extruder, and the level of the raw materials in the hopper scale gradually decreases accordingly.

After a predetermined time elapses until the lower limit quantity sensor issues an output signal, the weight of the hopper scale is measured again based on the distortion of the load cell. This becomes the secondary weight measurement.

As soon as this measurement result is measured, the arithmetic unit calculates the difference between the primary weight measurement value and the secondary weight measurement value, and divides this difference by a predetermined time to calculate the raw material consumption weight per unit time.

Finally, the results are digitally displayed on a display device such as a cathode ray tube or printing device.

In the method of claim 2, the second weight measurement is performed 36 seconds after the first weight measurement.

In the apparatus of claim 5, when a single molded product is connected to two or more extruders, each extruder performs the same function as described above.

In the apparatus according to claim 7, the gate of the raw material reservoir section, that is, the second opening/closing gate is closed simultaneously with the output signal of the lower limit amount sensor, and the weight of the hopper scale at that time is measured by the distortion of the load cell, and then the upper limit amount level is determined. Immediately after the gate of the feeding device is closed after receiving the output signal from the sensor, the weight of the hopper scale is measured again, and the total weight of the raw material fed to the hopper scale is determined from these two weight values.

During this time, the raw material on the downstream side of the second opening/closing gate of the raw material reservoir is continuously supplied to the extruder, but the raw material in the supply hopper remains in the same state.

Next, when the second opening/closing gate is opened, the raw material in the raw material reservoir section flows out onto the raw material under the second opening/closing gate again, and the raw material in the hopper scale is discharged in accordance with this outflow, and the raw material in the hopper scale is discharged. The discharge flow rate matches the discharge rate of the supply hopper scale, and becomes stable after a few seconds. At this point, the primary weight measurement according to claims 1 and 3 is carried out, and the same effect as in claim 3 is performed below.

Further, the measured weight of the entire amount supplied to the hopper scale is accumulated by the arithmetic unit, and the previous weight and cumulative value of these hopper scales are also displayed on the display unit.

Pellets are most preferred as the raw material used in this invention, but recycled pulverized raw materials and film pulverized raw materials may be used alone or in combination with the pellets.

(Examples) Example 1 An example of a representative SEA as claimed in claim 5 for carrying out the method invention as claimed in claim 1 of this application will now be described.

This is shown in Figures 1 and 2, and in Figure 1, 1
0 is an extruder, and 11 is a short cylindrical body forming a raw material supply port of the extruder 10 and serving as a raw material reservoir. A short hopper lla is connected to this cylinder 11. 13 is an inflation molding die connected to the discharge port 14 of the extruder 10.

Reference numeral 20 denotes a hopper scale, which shares a vertical axis with the cylindrical body 11 and is installed in the machine frame 22 through a load cell 21 so as to overlap with the hopper scale, and is not in contact with the extruder 10 or is a gravity blocking member. For example, they are connected via a bellows-shaped thin film 15. Immediately above the discharge port 23 of this hopper scale 20, a cap 24 is fixed to the hopper scale 20 itself, and a gap 26 around the cap 24 and the tapered surface 25 of the hopper scale 20 communicates with the discharge port 23. It has been done,
The size of this gap 26 and the discharge port 23 is determined by the size of the cylindrical body 11.
The size of the extruder 10 is such that a flow rate larger than that of the raw material supplied to the extruder 10 from the extruder 10 can be supplied.

The load cell 21 is used as a sensor for detecting the upper limit (weight) and lower limit (weight) of the raw material in the hopper scale 20, and the upper limit weight and lower limit weight are set in advance, and the corresponding When the weight of the raw material reaches this value, the value of this load cell is used as an input signal, and a computer is used to generate a signal corresponding to these values. The accumulation of raw material given by the limit value sensor is equivalent to about 1 kg, although it depends on the size of the extruder.

Reference numeral 30 denotes a raw material supply device for supplying raw materials to the hopper scale 20, and in the illustrated example, it consists of a storage tank 31, an opening/closing gate 32 at the lower end of the storage tank 31, and a hydraulic or pneumatic opening/closing gate drive device 33, which is a type of supply drive device. The opening/closing gate driving device 33 operates the opening/closing gate 32 based on the output signal of the lower limit weight value sensor in the hopper scale 20.
The gate 32 is operated in the direction of opening, and the gate 32 is operated in the direction of closing based on the output signal of the upper limit weight value sensor.

Next, to measure the strain in the load cell 21, a first measurement is performed immediately after the opening/closing gate 32 is closed (approximately 0.5 to 5 seconds later), this is memorized, and then a predetermined period of time (in the example,
6 seconds later), a second measurement is performed again, and a calculation device 40 calculates the amount of raw material consumed during a predetermined period of time (36 seconds) based on these two measurement values and the required time, and displays this result digitally. A display device 50 is provided.

The aforementioned calculation bag W140 and display device 50 use a controller having these functions.

In addition, this controller has a total of 8 settings between the first and second upper and lower limit weight values mentioned above! Settings between i and i can be set using the input section, and in addition to the above-mentioned calculations, it also has the functions of measuring the embodiment, transmitting upper and lower limit weight value detection signals, and issuing operation commands to the opening/closing gate actuating device of the supply device 40. It is something.

(Explanation of an example of the operation and method of Example 1) First, when all the devices are operated, the lower limit weight value sensor emits an on signal because the hopper scale 20 is empty, and the gate 32 is opened by the gate drive device 33 to open the storage tank. The raw material in 31 passes through the hopper scale 20 and is transferred from the cylinder 11 to the extruder 1.
0. The flow rate of the raw material supplied from the raw material supply device 30 is set higher than the flow rate of the raw material supplied to the extruder 10, and the raw material gradually reaches an angle of repose α within the cylinder 11.
is formed and accumulated, and the top of this raw material reaches the hopper scale 20.
When the raw material reaches the discharge port 23 of the hopper scale 20, the discharge of the raw material from the hopper scale 20 stops or becomes slow, and the raw material accumulates in the hopper scale 20, exceeding the lower limit weight value, and the output of this lower limit weight value sensor is turned off. When the raw materials have finally accumulated up to the upper limit weight, the load cell 21 indicates the upper limit value, and based on this value, the upper limit weight value sensor issues an output signal, and the gate 32 is closed by the gate driving device 33 based on this output signal.

On the other hand, the bubble extruded from the molding die 13 connected to the extruder 10 is filled with air at an appropriate pressure, held between pinch rollers 15, and made into a bubble of a predetermined diameter by a cooling air ring 16, an iris ring 17, etc. from the outside of the bubble. .

When the operation continues in this manner, the raw material in the cylinder 11 is sequentially supplied to the extruder 10 and decreases, and as the raw material decreases, the raw material in the hopper scale 20 passes through the gap 26 between the jinkasa 24 and the tapered surface 25. The raw material level in the hopper scale 20 gradually decreases, the upper limit weight value sensor turns off, and finally the lower limit weight value sensor issues an on signal again. , the gate 32 opens again as before, and the raw material is transferred to the hopper scale 2.
0 until the weight value reaches the position of the upper limit weight value sensor.

To measure the strain of the load cell 21 now, the signal for closing the gate 32 is used as an input signal, and the one-shot circuit 41 first measures the strain of the load cell 21 at that time and stores it.

Next, the distortion of the load cell is secondly measured again using the time-up signal of the timer 42 from the signal that closes the gate 32.

Next, the weight of the raw material discharged from the hopper scale 20, that is, the flow rate, is calculated by the arithmetic unit 140 based on the first and second measured values and the predetermined time of 36 seconds, and the display unit 50 calculates the weight of the raw material, that is, the flow rate per hour. indicate.

Embodiment 2 In the embodiment shown in FIGS. 3 and 4, the same reference numerals as in Embodiment 1 indicate the same constituent members or parts, and have the same functions.

The difference is 1. The raw material reservoir forming the raw material supply port of the extruder 10 consists of a relatively large supply hopper 12,
The discharge port 23 of the hopper scale 20 is connected to the supply hopper 12.
It is inserted inside.

In the first embodiment, the sensor for detecting the upper and lower limits of the amount in the hopper scale 20 is a computer that uses the output signal of the load cell as an input signal and generates an output signal when 29 reaches a predetermined value. However, in this second embodiment, bulk level sensors 27 and 28 that directly detect the bulk of the raw material in the hopper scale 20 are provided on the hopper scale 20, and the upper and lower bulk level sensors 27
When .degree. 28 indicates the upper limit bulk amount and the lower limit bulk amount, respectively, an output signal is generated (see FIGS. 3 and 4).

Effect of Example 2 The operation of this embodiment is generally the same as that of the first embodiment.

The difference is that the flow rate of the raw material discharged from the discharge port of the hopper scale 20 is higher than the flow rate of the raw material sent out by the extruder 10, so if the gate 32 of the H hot water supply device 30 is opened, the raw material will flow into the supply hopper 12. is supplied sequentially, forming an angle of repose α, and finally blocks the discharge port 23 of the hopper scale 20 at the top, and further accumulates in the hopper scale 20 until the amount reaches the upper limit bulk level sensor 27. , when the raw material is supplied, the upper limit bulk level sensor 27 issues an output signal and the supply of the raw material is stopped.

When the extruder 10 is operated and raw materials are consumed.

The raw materials sequentially flow into the extruder through the feed hopper 12, and as the raw material in the feed hopper 12 decreases, a commensurate amount of raw material flows down into the feed hopper 12 from the discharge port 23 of the hopper scale 20.

Then, when the level in the hopper scale 20 decreases to the level of the lower limit bulk level sensor 28, the lower limit bulk level sensor 28 issues an output signal, and the gate 3 of the starting and feeding device 30 is activated.
2 opens again.

The above operations are repeated, and other operations are the same as in the first embodiment.

Embodiment 3 This is an embodiment of claim 7, and is shown in FIGS. 5 and 6, where the same reference numerals as in Embodiments 1 and 2 indicate the same constituent members or parts, and the same play an action.

The difference is that the weight of all raw materials supplied to the hopper scale 20 can be measured, and for this purpose the following device is added.

That is, a second opening/closing gate 61 is provided near the top of the cylindrical body 11 and can be opened and closed by a second drive device 62. In this embodiment, the raw material reservoir is formed by a cylindrical body 11 and a hopper 12 connected thereto.

The operation of the third embodiment: First, the second opening/closing gate 61 is closed by the output signal of the lower limit weight value sensor mentioned above, and at the same time, the weight value (minimum weight) W is measured by the arithmetic unit 40 from the strain of the load cell 21, and this is Remember.

Next, the opening/closing gate 32 of the supply device 30 is opened and the raw material is put into the hopper scale 20 from the supply device 30, and when the weight of the raw material in the hopper scale 20 reaches a predetermined upper limit weight, the upper limit weight value sensor outputs an output signal. Emitting and supplying device 3
0 opening/closing gate 32 closes, and at the same time, the distortion of the load cell 21 is read again as a weight value by that signal, the maximum weight value W of the hopper scale 20 is read, and the difference from the previously stored minimum weight value W3 is calculated by the calculation device. 40, the total weight of one batch supplied to the hopper scale is calculated and displayed on the display device 50.

Even when the second opening/closing gate 61 is closed and raw materials are being supplied to the hopper scale 20, the raw materials in the cylindrical body 11 under the second opening/closing gate 61 are sequentially supplied to the extruder 10, and the top of the raw materials in this is supplied to the extruder 10. It is lower than the second opening/closing gate 61 and is separated from it.

Once the maximum weight value W of the hopper scale 20 is measured, a command signal is immediately issued to the second driving device 62 to open the second opening/closing gate 61, and the second opening/closing gate 61 opens the second opening/closing gate 61. is opened, the raw material above the second gate 61 is supplied to the extruder, and with this supply, the raw material in the hopper scale 20 begins to flow into the cylinder 11 and the supply hopper 12, and the raw material in the supply hopper 12 is Since it forms the angle of repose α and reaches the discharge port 23 of the hopper scale 20, it is subsequently discharged from the supply hopper 12. The raw material flow rate and the discharge flow rate of the hopper scale become equal.

In this third embodiment, the time from opening the second opening/closing gate 61 of the hopper scale 20 until the discharge flow rates of the supply hopper 12 and the hopper scale 20 match is approximately 2 seconds to 3 seconds. It's Nishide.

Therefore, an appropriate time approximately 3 to 5 seconds after the second opening/closing gate 13 opens is set as the above-mentioned first measurement time, and the weight at that time is measured. Let it be an action.

Further, the display device 50 not only displays the flow rate each time as in the first embodiment, but also has the function of digitally displaying the total weight value and the cumulative value each time.

Effects of the Invention In the method described in claim 1), since it is configured as described above, the flow rate of the raw material discharged from the hopper scale to the raw material reservoir and the supply of pellets from the raw material reservoir to the extruder are controlled. Since the flow rate is almost the same as the flow rate, it is possible to measure the discharge flow rate of the hopper scale by weight without stopping the extruder each time the extruder is supplied to or discharged from the extruder.

In the apparatus invention of claim 3, the method of claim 1 can be carried out because it is configured and operates as described above, and in addition to the method of claim 1, while the extruder is in operation, while continuing molding, The raw material is supplied until the upper limit sensor issues a signal, and the consumed weight of the raw material can be measured intermittently for a predetermined period of time immediately after the gate of the supply device is closed, so the flow rate value is measured from the forming die through the hopper scale discharge port. It corresponds with the discharge weight of the molten resin extruded from the extruder with high precision, with a time lag corresponding to the passage time of the resin until discharge.

In particular, among the raw materials in the hopper scale, the raw material directly below the Jinkasa is supported in the supply hopper, but the other parts of the hopper scale are all supported by the lower tapered part of the hopper scale and the Jinkasa. Therefore, the weight of the raw material in the lower part of the aforementioned Jinka is not measured, and the weight of the raw material in the hopper scale almost corresponds to the raw material fed into the extruder.

Therefore, by knowing the weight of raw material consumed per unit time in such a method and apparatus, it is also possible to measure the bubble diameter of the inflation tube extruded from the forming die and the fold width when it is made into a flat tube. , can be a factor when calculating the thickness of the film.

Furthermore, in the apparatus of claim 5, since the consumed weight of the raw material is measured independently for each extruder, it is also possible to calculate the thickness of each layer in the product from this consumed weight ratio.

In the method of claim 2, since the required time is set to 36 seconds, the flow rate can be easily calculated by multiplying the consumed weight of the raw material for 36 seconds, that is, the flow rate by 100 to obtain the flow rate per hour.

When the upper and lower limit quantity sensors are weight value level sensors based on distortion of the load cell, the load cells used to calculate the flow rate can be used, and output signals are generated when the upper and lower weight limits are reached. This simplifies the mechanical structure of the device.

When the upper and lower limit sensors are bulk level sensors that detect bulk, their outputs simply turn off and on, making it easy to electrically take out the signal.

In addition, in the device according to claim 7, the total weight of the weight supplied from the supply device to the hopper scale each time is separated and added up each time, and the measurement of the total weight and the flow rate measurement each time can be performed together.

It should be noted that even if this device is used in a blown film molding machine, a T-die film molding machine, or any other extruder that performs extrusion molding, it is within the scope of the present invention.

(Effects of Embodiment 1) In this embodiment, which is configured diagonally upward and performs one action, the method of the present invention can be implemented and the same effects as the device invention can be achieved.

In particular, since the flow rate per hour is displayed on the display device 50, it is easy to record it or read it with the naked eye.

As shown in the signal flowchart of FIG. 2, this device is used in combination with the device shown below outside the dashed line frame, that is, a sensor for measuring the diameter or folding width of a film tube blown out from the forming die 13 and formed. The thickness of the molded product can be calculated based on the output value of 18 and the flow calculated by the calculation device 40, and the multilayer inflation tube can be manufactured using two or more extruders to produce a single molded product. For molding products, by using these devices A, A, etc. for each extruder frame,
The ratio can be determined from the raw material consumption of each layer, and by measuring the diameter or fold width of the molded product, the thickness of each layer can be accurately calculated from these values (see Figure 2 - dot-dashed line and below).
.

Note that a one-chip computer or a part of a small to large-sized computer is used to execute the program for reading the strain of the load cell 21 and issue instructions to the arithmetic unit and display device.

Also, when detecting the upper and lower limits of the raw material in the hopper scale 20 by weight, the load cell 21 is used to issue an output signal when the upper limit weight or lower limit weight is reached, respectively. Since the gate is activated, these programs can also be executed by a computer, and there is no need to provide a separate mechanical level sensor.

The unique effect of the second embodiment is that the raw material reservoir forming the raw material supply port of the extruder 10 is replaced by the supply hopper 12 having a relatively large diameter.
Since the raw material forms an angle of repose α therein, there is no fear that raw materials such as pellets falling from the hopper scale 20 into the supply hopper 12 will rebound and fly out.

A unique advantage of the third embodiment is that the flow rate and total weight consumed can be accurately measured with one device.

In addition, in each embodiment, even if each component is replaced with those shown in other embodiments, the raw material supply device 30
Even if the hopper scale 20 and the hopper scale 20 are connected by a bellows-like thin film that does not affect measurement, this is also included in the embodiment of the present invention.

[Brief explanation of the drawing]

The drawings show an embodiment of a typical device according to the present invention, and FIG. 1 is a mechanical diagram showing the mechanical part of Embodiment 1;
FIG. 2 is a block diagram showing the signal flow of the first embodiment, FIG. 3 is a mechanism diagram showing the mechanism diagram part of the second embodiment, and FIG. 4 is a block diagram showing the signal flow of the second embodiment. FIG. 5 is a mechanical diagram showing the mechanical parts of the third embodiment, and FIG. 6 is a block diagram showing the flow of the third embodiment. Reference numeral 1o in the figure: Extruder, 11: Cylindrical body, 12: Supply hopper, 20:
...Hopper scale, 21...Load cell, 2
2...Machine frame, 23...Discharge port,
24... Jinkasa, 27... Upper limit level sensor, 28... Lower limit level sensor. 30... Raw material supply device. 40... Arithmetic device, 50... Display device. 61...Second opening/closing gate. Condolences 5

Claims (1)

[Claims] 1) When the raw material discharged from the open discharge port of the hopper scale is supplied into the supply hopper of the extruder, the raw material rests in the raw material reservoir forming the raw material supply port of the extruder. A method in which the top of the raw material deposited forming an angle reaches the discharge port of the hopper scale, and with this closed, the same amount of raw material is sequentially discharged from the hopper scale as the raw material in the reservoir decreases. Next, every time the raw material in the hopper scale reaches the lower limit predetermined amount, the raw material is supplied up to approximately the upper limit predetermined amount, then the raw material supply to the hopper scale is stopped, and then the first
Measure the secondary weight, then measure the secondary weight after a predetermined time from the time when this primary weight was measured until the raw material in the hopper scale reaches the lower limit predetermined amount, and finally measure the secondary weight. The raw material discharge weight per unit time is calculated from the difference between the weight value and the secondary weight value and the predetermined time, and this is digitally displayed. A gravimetric measurement method for raw material consumption in an extruder comprising the above method. 2) A gravimetric measuring method for raw material consumption in an extruder according to claim 1, wherein the predetermined time is 36 seconds. 3) A load cell-type hopper scale, which is equipped with an umbrella-shaped baffle near the upper part of the discharge port and serves as a normally open discharge port, is stacked on top of the raw material reservoir of the extruder, and the discharge port is located inside the raw material reservoir. Further, the discharge port of the hopper scale is sized to be able to discharge a flow rate larger than the raw material consumption flow rate of the extruder, and a raw material supply device with an opening/closing gate is provided above the hopper scale. A raw material supply drive device is provided which starts supplying the raw material in response to an output signal from a raw material lower limit amount sensor in the hopper scale, and stops the raw material supply in response to an output signal from a raw material upper limit amount sensor in the hopper scale. , a measuring device that measures the weight of the hopper scale based on the distortion of the load cell twice, once after the gate is closed after the raw material is supplied, and after a predetermined time; A gravimetric measuring device for raw material consumption in an extruder, comprising a calculation device for calculating raw material consumption and a display device for digitally displaying the calculation results. 4) Raw material consumption in an extruder according to claim 3, wherein the extruder is an extruder equipped with several extruders for molding a single molded product. gravimetric measuring device. 5) The upper and lower limit amount sensors of the raw material in the hopper scale are upper and lower limit weight value sensors that issue output signals when the strain value of the load cell indicates an upper or lower limit value. A gravimetric measuring device for raw material consumption in an extruder according to scope 3. 6) The weight of the raw material consumption amount in the extruder according to claim 3 or 4, wherein the upper and lower limit amount sensors of the raw material in the hopper scale are respectively bulk sensors provided in the hopper scale. Expression measuring device. 7) The discharge port of the hopper scale is provided with a second opening/closing gate that closes in response to the output signal of the lower limit level sensor and opens after closing the gate of the raw material supply device, and the calculation device
The weight due to distortion of the load cell immediately after closing the opening/closing gate and the weight due to distortion of the load cell between the closing of the gate of the supply device and the opening of the second opening/closing gate are measured, and the difference between these values determines the amount of material supplied to the hopper scale. Claim 1, characterized in that the device also has a function of calculating and sequentially accumulating the amount supplied each time, and the display device also displays the calculated amount of each amount supplied and the cumulative value. A gravimetric measuring device for raw material consumption in the extruder according to item 3 or 4.