JPH059331A - Automatic apparatus for measuring ratio - Google Patents

Abstract

PURPOSE:To obtain the subject apparatus, equipped with a cylindrical measuring vessel having a feed port and a discharge port of preexpanded particles and an openable and closable damper, a filling feeder and a device for measuring the weight of a resin and controlling the feed rate and capable of providing stable quality and high productivity. CONSTITUTION:An automatic apparatus 21 for measuring the expansion ratio is provided with a cylindrical measuring vessel 23 having a feed port 31 and a discharge port 34 for preexpanded particles 42 in respective upper and lower parts and an openable and closable damper 29 for forming a measuring space 30 in the interior, a filling feeder 24, arranged above the feed port 31 and feeding part of preexpanded particles 42 discharged from a batch type preexpanding machine 1 into the measuring space 30, a weight measuring instrument 25 for supporting the measuring vessel 23, measuring the weight of the preexpanded particles 42 in the measuring space 30 and issuing its value as an electrical signal and a controller 27 for receiving the issued electrical signal, converting the signal into the expansion ratio of the preexpanded particles 42, issuing a control signal corresponding to the deviation of the converted value from the preset prescribed expansion ratio and regulating the raw material feed rate into the preexpanding machine 1. The aforementioned apparatus 21 is used to automatically measure the expansion ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic magnification measuring device for automatically measuring the expansion ratio of pre-expanded particles obtained by expanding expandable thermoplastic resin particles by a batch type pre-expanding machine.

[0002]

2. Description of the Related Art Conventionally, in the case of producing a foamed resin product using expandable thermoplastic resin particles as a raw material, the raw material particles are pre-expanded to a predetermined expansion ratio, and the pre-expanded particles are further expanded by a molding machine. I am molding the product by
There are two methods for pre-foaming: continuous method and batch method (so-called batch method). Compared to the continuous method, the batch method has less foaming unevenness of the pre-expanded particles, a homogeneous product can be obtained, and it is possible to quickly respond to the requirements of various kinds of pre-expanded particles. The formula method is generally adopted.

In the batch type pre-expanding method, first, a predetermined amount of raw material particles are supplied to a pre-expanding machine to be pre-expanded to a predetermined expansion ratio by a heating medium such as steam, and then the pre-expanded particles are batch type. Take it out. Next, the extracted pre-expanded particles are supplied to the molding machine via the aging silo, and a part of them is sampled in a container such as a bucket and weighed, and the weight is expanded according to a conversion table. Convert to magnification. Next, this conversion value is compared with a preset predetermined expansion ratio, and the predetermined expansion ratio is maintained by adjusting the supply amount of the heating medium or the raw material particles to the pre-expansion machine according to the deviation between both expansion ratios. Was there. However, in the above operation, all operations after sampling and sampling are done manually.

[0004]

By the way, recently, the applications of foamed resin products have been varied from containers such as fish boxes and vegetable boxes to cushioning materials for home electric appliances. And the expansion ratio has become various,
Further, in order to stabilize product quality and improve productivity, the expansion ratio is strongly required to be accurate. However, even with the same expansion ratio, the amount of raw material supplied changes depending on the brand and particle size of the raw material particles,
Even with the same particle size, the content of the foaming agent in the raw material particles changes with time depending on the number of days from the production of the raw material particles to the difference in the foaming rate. Part of them may foam and the expansion ratio may change. Therefore, in order to obtain an accurate expansion ratio, accurate measurement of the expansion ratio is essential.

However, conventionally, since the operations after sampling and sampling are manually performed, there is a problem that the obtained expansion ratio varies among individuals and that the expansion ratio changes depending on the volume and shape of the measuring container. Further, there is a problem that the measurement is labor intensive. It is an object of the present invention to provide an automatic measuring device for the expansion ratio to eliminate the above-mentioned problems.

[0006]

In order to achieve the above object, an automatic magnification measuring device of the present invention is a cylindrical container having a supply port and a discharge port for pre-expanded particles in each of the upper and lower parts, A measurement container having a damper that can be opened and closed so as to form a constant volume of measurement space, and pre-expanded particles discharged from a batch-type pre-expanding device that is vertically arranged above the supply port of the measurement container. A filling feeder for supplying a part of the measurement space into the measurement space, supporting the measurement container, measuring the weight of the pre-expanded particles in the measurement space, and a weighing device transmitting the measurement value as an electric signal, The electric signal from the weighing device is received to convert it into the expansion ratio of the pre-expanded particles, and a control signal is transmitted according to the deviation between the conversion value and a preset predetermined ratio, so that the raw material to be fed into the pre-expansion machine. It is equipped with a control device for adjusting the supply amount. It is obtained by the configuration that.

[0007]

According to the automatic magnification measuring device having the above-described structure, when the pre-expanded particles are discharged from the pre-expanding machine, first, the filling feeder descends to come into contact with the supply port of the measurement container, and the discharged pre-expanded particles are discharged. Part of the sample is sampled and filled in the measurement space of the measurement container, then rises and separates from the supply port.
Next, the weighing device measures the weight of the pre-expanded particles in the measurement space, and sends the measured value to the control device as an electric signal.
Next, the control device receives the electric signal from the weighing machine to calculate the specific gravity, and converts the specific gravity into the expansion ratio of the pre-expanded particles. Then, the converted value is compared with a predetermined set magnification inputted in advance, and a control signal corresponding to a deviation between the two magnifications is transmitted to the weighing device of the raw material particle supply device. The weigher receiving the control signal adjusts the supply amount of the raw material particles to be used for the next prefoaming. On the other hand, the damper opens in the measurement container to discharge the pre-expanded particles in the measurement space to prepare for the next measurement.

As described above, the automatic magnification measuring apparatus of the present invention automatically measures the weight of a fixed volume of pre-expanded particles with a weighing machine, and the controller determines the weight as the expansion rate of the pre-expanded particles. It is converted and a control signal corresponding to the deviation between the expansion ratio and the predetermined expansion ratio is transmitted to automatically adjust the amount of raw material supplied to the batch type foaming machine.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic view of an embodiment in which an automatic magnification measuring device 21 of the present invention is applied to a batch type pre-foaming machine 1, and FIG. 2 is an enlarged sectional view of a main part of the automatic magnification measuring device 21. As shown in FIG. 1, the pre-foaming machine 1 has a foaming tank 3 on a base 2.
And the granulation hopper 4 is attached to the discharge side of the foaming tank 3. The foaming tank 3 pre-expands the raw material particles supplied from the upper supply port 5 with a heating medium such as steam to a predetermined expansion ratio, and then discharges the pre-expanded particles batchwise from the lower discharge port 6. It has an agitator (not shown) inside, and is provided with a shutoff valve 7 at the supply port 5 and an air cylinder drive type lid 8 at the discharge port 6.

The granulating hopper 4 receives pre-expanded particles discharged from the foaming tank 3 and supplies the pre-expanded particles from a lower discharge port 9 to a molding machine through an aging silo. A sieve 10 for removing particles is stretched, a sampling suction pipe 11 is projected below the sieve 10, a granulation blower 12 is connected to the discharge port 9, and a recovery feeder 13 is provided on the upper portion. .

As shown in FIGS. 1 and 2, the automatic magnification measuring device 21 suspends a measuring container 23 and a filling feeder 24 in a case 22 by means of a weighing device 25 and an air cylinder 26, respectively, and controls them. 27 is attached. The measurement container 23 is a cylindrical container, and the motor 2 is provided inside.
A rotary damper 29 which is opened and closed by 8 is mounted so as to form a measurement space 30 having a constant volume above the pre-expanded particle supply port 31 and cleaning air port 32, and a receiving hopper 33 at the lower part. ing. The cleaning air port 32 is
It is connected to a compressed air source via a hose. The receiving hopper 33 has a discharge port 34 at the lower end connected to the recovery feeder 13 of the grain feeding hopper 4 via a flexible tube 35. In addition,
The measurement container 23 is preferably made of a punching plate or a wire net in order to separate the pre-expanded particles filled in the measurement space 30 from the air, and the damper 29 may be of a slide type or the like.

The filling feeder 24 is arranged above and below the supply port 31 of the measuring container 23 by an air cylinder 26, and is arranged at the bottom of the supply port 31 so as to be able to come into contact with and separate from it in order to eliminate measurement errors. The flexible tube 36 is connected to the suction tube 11 of the grain feeding hopper 4. The scale 25
It is composed of a load cell or the like, and is adjusted in advance so that it will be 0 point when the inside of the measurement container 23 is empty.

The control device 27 is for automating a series of operations from the measurement of the expansion ratio of the pre-expanded particles to the adjustment of the supply amount of the raw material particles to the foaming tank 3.

In the above structure, first, the shutoff valve 7 is opened, and a predetermined amount of the raw material particles 41 are supplied from the supply port 5 into the foaming tank 3 by the raw material particle supply device (not shown), and then the shutoff valve 7 is closed. . As the raw material particles 41, polystyrene resin, polyolefin resin particles such as polyethylene and polypropylene, polyurethane resin particles and the like are used. Then, a heating medium such as steam is blown into the foaming tank 3 to pre-foam the raw material particles 41 to a predetermined foaming ratio, and then the lid 8 is opened to pre-foam particles 42 from the discharge port 6 into the granulating hopper 4. Pre-expanded particles 4 discharged into the inside and sized by the sieve 10.
2 is fed to the molding machine from the discharge port 9 through the grain-blowing blower 12 via the aging silo.

At this time, the signal from the controller 27 causes
The air cylinder 26 lowers the filling feeder 24 to contact the bottom of the supply port of the measurement container 23,
The pre-expanded particles 42 through the flexible tube 36 and the suction tube 11.
Is sampled and filled in the measurement space 30 of the measurement container 23. When the filling is completed, the air cylinder 2
6 raises the filling feeder 24 to separate it from the supply port 31. Next, the weighing device 25 measures the weight of the pre-expanded particles 42 in the measurement space 30, and sends the measured value to the control device 27 as an electric signal. The control device 27 uses the weighing device 2
After storing the electric signal from 5, the motor 28 is rotated to open the damper 29, the pre-expanded particles 42 in the measurement space 30 are received and discharged into the hopper 33, and the discharge port 34 through the flexible tube 35. The particles are collected in the particle feeding hopper 4 by the collecting feeder 13. Then, from the cleaning air port 32 to the measurement container 23
After blowing compressed air into the inside to clean the inside,
The damper 29 is closed by 8 to prepare for the next measurement.

When the same operation as described above is repeated a predetermined number of times (for example, about three times), the control device 27 averages a plurality of measured weights from the weighing machine 25 to calculate the specific gravity of the pre-expanded particles 42, and the specific gravity is calculated. Convert to foaming ratio. Then, the converted value is compared with a predetermined set magnification input in advance, and a control signal corresponding to a deviation between the two magnifications is transmitted to the weighing device 25 of the raw material particle supply device. The weighing device 25 receives the control signal and adjusts the supply amount of the raw material particles 41 used for the next pre-foaming, and then supplies the raw material particles 41 to the foaming tank 3. After that, the above-mentioned series of operations is repeated, which makes it possible to perform pre-foaming with an extremely accurate expansion ratio.

The results of the prefoaming test carried out using the present invention are shown in Table 1. Expanded polystyrene resin particles (Kaneka Chemical Co., Ltd., trade name "Kaneka S"
G ”) and Table 1 shows the setting magnification is 55 times.
Indicates the case where the set magnification is 58 times.

[0018]

[Table 1]

Explaining the measurement magnification of the present invention in Table 1, the magnification of the first foaming deviates greatly from the set magnification, but this is due to residual moisture in the foaming tank and is not helpful, so it is ignored. The same raw material particle supply amount of 17.3 kg is applied to the second and subsequent foaming. And the second time
Since the average magnification in the 4th foaming was 54.5 times, the raw material particle supply amount was 17.2 kg in the 5th foaming and thereafter.
Is automatically adjusted. As a result, the magnification in the fifth to tenth foaming is almost the same as the set magnification.

On the other hand, the measurement magnification in the conventional method is
The accuracy is gradually increasing as the number of times of foaming increases.
There are still many variations.

[0021]

[Table 2]

In Table 2, the measurement magnification of the present invention is from the first time to
Since the average magnification in the third foaming was 58.7, the raw material particle supply amount was 15.9 Kg in the fourth foaming and thereafter.
It is automatically adjusted from 16.0 kg. Therefore, the average magnification in the 4th to 6th foaming was reduced to 57.5 times. This is because the raw material supply amount is excessively adjusted, so that the raw material particle supply amount is readjusted to 15.95 Kg for the seventh and subsequent expansions. As a result, the magnification in the 7th to 10th foaming is very close to the set magnification.

From Tables 1 and 2, it was found that by automatically adjusting the feed amount of the raw material particles to the foaming tank, the pre-foaming according to the set magnification was automatically performed.

[0024]

As described above, according to the present invention, the weighing machine automatically measures the weight of a fixed volume of pre-expanded particles, and the controller converts the weight into the expansion ratio of the pre-expanded particles,
Since a control signal corresponding to the deviation between the expansion ratio and the predetermined expansion ratio is transmitted to automatically adjust the amount of raw material supplied to the batch type pre-foaming machine, only labor saving is possible. In addition, there is no room for individual differences in the measured expansion ratio, and since the capacity and shape of the measuring container are constant, the measured value is extremely accurate, and it is easy to respond to small changes in the expansion ratio. be able to. Therefore, accurate pre-foaming is possible, the product quality is stable, and the productivity is improved.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment in which an automatic magnification measuring device of the present invention is applied to a batch type prefoaming machine.

FIG. 2 is an enlarged sectional view of an essential part of the automatic magnification measuring device of the present invention in the above embodiment.

[Explanation of symbols]

 Single batch pre-foaming machine 21 Automatic magnification measuring device 23 Measuring container 24 Filling feeder 25 Weigher 27 Control device 29 Damper 30 Measuring space 31 Supply port 34 Discharge port 41 Raw material particle 42 Pre-foaming particle

Claims (1)

Claim: What is claimed is: 1. A cylindrical container, which has a supply port and a discharge port for pre-expanded particles in the upper and lower parts, respectively, and which can be opened and closed so as to form a measurement space of a constant volume inside. A measuring container having, and a filling feeder that is arranged to be movable up and down above the supply port of the measuring container and that supplies a part of the pre-expanded particles discharged from the batch-type pre-expanding machine into the measurement space,
The weighing container supporting the measurement container, measuring the weight of the pre-expanded particles in the measurement space, and transmitting the measured value as an electric signal, and the pre-expanded particles of the pre-expanded particles receiving the electric signal from the weigher. An automatic scaler comprising a control device for converting the foaming ratio and transmitting a control signal according to the deviation between the conversion value and a preset predetermined ratio to adjust the raw material supply amount into the preliminary foaming machine. measuring device.