JPH05112666A - Apparatus for automatic determination of expansion ratio of pre-expanded bead - Google Patents

Abstract

PURPOSE:To provide the subject apparatus effective for suppressing the generation of uneven packing density to enable accurate determination of the density by providing a pneumatic conveying apparatus for transporting pre-expanded beads with air flow into a fixed volume vessel having a vent hole. CONSTITUTION:The apparatus A for the automatic determination of the expansion ratio of pre-expanded bead 1 is composed of a fixed volume vessel 2 for holding a prescribed volume of pre-expanded bead 1 to determine the volume of the pre- expanded bead 1 and a weighing apparatus 3 for determining the weight of the pre- expanded bead 1 having prescribed volume measured by the fixed volume vessel. In the above apparatus, the stock resin 1a dropped from a raw material feeding hopper 17 is continuously supplied to the bottom of an expansion tank B with a screw 10 of a raw material feeding cylinder 9 and the obtained pre-expanded bead is transferred to a dry bed 11 through a discharging pipe 18, stored in the bed and transferred to the fixed volume vessel 2 of the automatic expansion ratio determination apparatus A with a pneumatic conveying apparatus 4 for transporting the stored pre-expanded beads 1 with air flow. The fixed volume vessel 2 is provided with a vent hole 2a. The pre-expanded beads 1 can uniformly be transported to and filled in the fixed volume vessel 2 with air flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic expansion ratio of pre-expanded particles for automatically and continuously detecting a change in the pre-expansion ratio of expandable thermoplastic resin particles to be pre-expanded in a pre-expansion device. The present invention relates to a measuring device.

[0002]

2. Description of the Related Art Generally, raw material resin particles are foamed to a predetermined apparent specific gravity before in-mold molding by a foam molding machine, which is called pre-foaming. This pre-foaming is generally carried out by continuously supplying the raw material resin particles to the lower part of the foaming tank equipped with a stirring arm, allowing water vapor to flow therethrough for foaming, and taking out this. In the particles pre-expanded in this way, the expansion ratio is varied due to the variation in the content of the foaming agent, the variation in the particle size, and other factors, which causes the variation in the quality of the foam-molded article. Therefore, the expansion ratio is constantly measured, and the measurement result is fed back to the expansion tank to control the expansion ratio to fall within a certain range.

As an automatic magnification measuring device (C) for such pre-expanded particles (1), the one described in JP-A-57-167221 has been proposed. This automatic magnification measuring device (C) is a weighing container (50) and a measuring container (51) connected to the weighing device (50) and pre-expanded particles (1) in a measuring container (51) at regular intervals. Leading supply device (52), measuring the weight of the pre-expanded particles (1) housed together with the measuring container (51) and the container (51) to make the pre-expanded particles (1) a constant volume, pre-expanded particles (1) Measuring unit (50a) for calculating the specific gravity by dividing the stored volume of the unit by its weight, and a discharge device (55) for removing the measured pre-expanded particles (1) from the measuring device (C). ing.

In this conventional automatic magnification measuring device (C), the one in which the expansion ratio of the pre-expanded particles (1) was manually measured before that can be automatically measured. As a method of filling the pre-expanded particles (1) into the measurement container (51), the pre-expanded particles (1) are mechanically charged into the measurement container (51) by self-weight drop, and along the upper end opening of the measurement container (51). The sliding plate (54a) of the discharging device (54) is moved to scrape off the pre-expanded particles (1) rising from the upper end opening, so that a bridge may be generated inside and the filling may be uneven. Occurrence occurred, and there were variations in the accuracy of measurement of the expansion ratio.

Further, the looseness of the slide plate (54a) may collide with the measuring container (51), and a horizontal force may be applied to the measuring container (51) to damage the weight measuring device (50). Further, there is a problem that the arrangement of the measuring container (51) is fixed and the device cannot be freely laid out because of the mechanical method. Further, since the supply device (52) for filling the pre-expanded particles (1) in the measurement container (51) is arranged in parallel with the measurement container (51), there is also a problem that a lot of device space is required. It was In addition, in order to discharge the measured pre-expanded particles (1), the measurement container (51) was covered with a discharge duct (55) that moves up and down, and then suctioned and discharged.
Pre-expanded particles (1) may adhere and remain in the corners of (51),
It was a cause of measurement error.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the problems of the conventional example, and the filling of the pre-expanded particles in the fixed quantity container by the emptying and filling means is always constant and the density does not occur. The accuracy of foaming ratio measurement can be increased, and
The problem to be solved by the present invention is to make it possible to give flexibility to the arrangement of equipment by using a large amount of idle feeding means, and also to make the equipment space small.

[0007]

An automatic magnification measuring device (A) for solving the above-mentioned problems in the present invention, as shown in claim 1, stores a predetermined amount of pre-expanded particles (1) and pre-expands them. Particle (1)
Of the pre-expanded particles (1) composed of a quantitative container (2) for measuring the volume, and a weight measuring device (3) for measuring the weight of the container expanded particles (1) quantified by the quantitative container (2) The automatic magnification measuring device (A) is equipped with a pre-expanded-particles air-feeding device (4) for allowing the pre-expanded-particles (1) to be placed in air-conveyed air and stored in the quantitative container (2). It is characterized in that it is composed of a fixed quantity container (2) formed into a shape. As a result, the fixed quantity container (2) is filled with the pre-expanded particles (1) by the pressure of the air to be fed, so that it is possible to perform uniform filling each time, and there is no variation in the filling volume into the fixed quantity container (2). ..

Furthermore, the automatic magnification measuring device (A) of the present invention is
As shown in claim 2, the pre-expanded particles (1) are stored in a fixed amount and the pre-expanded particles (1) are contained.
Of the pre-expanded particles (1) composed of a quantitative container (2) for measuring the volume, and a weight measuring device (3) for measuring the weight of the container expanded particles (1) quantified by the quantitative container (2) In the automatic magnification measuring device (A), the fixed quantity container (2) is the weight measuring device (3).
The bottom opening / closing device (5) is installed at the bottom of the fixed quantity container (2). As a result, the device space can be reduced.

In addition to this, the automatic magnification measuring device (A) of the present invention is, as shown in claim 3, an automatic magnification measuring device (A) for pre-expanded particles (1) according to claim 1 or 2. ), The weight measuring device (3) is equipped with a particle suction / discharge device (6) for discharging the weighed particles (1) from the weight measuring device (3). Thus, the pre-expanded particles (1) can be supplied and discharged by the air-feeding means, and the layout of the device can be freely set.

Further, as described in claim 4, by feeding back the measurement result to the foaming tank and controlling so that the expansion ratio falls within a predetermined expansion ratio range, it is possible to always maintain the predetermined expansion ratio. The stability of the quality of the foam molded product is stable.

[0011]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a sectional view of an automatic magnification measuring device (A) and a foaming tank (B) according to the present invention. The foaming tank (B) shown in the figure is of a continuous type, and a stirring arm (7) is erected at the center thereof and is rotated by a drive motor (8). A raw material resin supply device (52) is connected to the bottom of the foaming tank (B), and a raw material supply hopper (1
The raw material resin (1a) dropped from the 7) is continuously supplied to the bottom of the foaming tank (B) by the screw (10) of the raw material supply cylinder (9).

Further, high temperature steam is supplied to the foaming tank (B) and flows through the raw material resin (1a), and the raw material resin (1a) is heated and foamed by this. The raw material resin (1a) gradually rises while foaming, and when the foaming is completed, the discharge tube (1
It is discharged from 8) to the dry bed (11) and dried. Discharge tube
The (18) can be moved up and down by an elevating cylinder (17) so that the pre-expanded particles (1) at any position in the foaming tank (B) can be discharged. The dry bed (11) is a large container for storing the pre-expanded particles (11), and the automatic magnification measuring device (A) is the pre-expanded particles (1) stored in the dry bed (11). Are properly taken out and weighed. The foaming tank (B) of the present embodiment shown in the figure is of a continuous type, but a batch type can of course be used.

Automatic magnification measuring device (A) for pre-expanded particles (1)
Is a pre-expanded particle (1) containing a fixed amount of pre-expanded particle (1)
Consists of a quantitative container (2) for measuring the volume, and a weight measuring device (3) for measuring the weight of the expanded beads (1) of the container quantified by the quantitative container (2). ) Is equipped with a pre-expanded particle feeding device (4) for placing the pre-expanded particles (1) on the suction air and storing it in the quantitative container (2), and the quantitative container (2) is empty. An air vent (2a) is formed to bleed air. Of course, the quantitative container (2) may be formed in a cage shape.

The pre-expanded particle air-conveying device (4) used in this embodiment is of a venturi type, and an air pressure source (12) is provided in a particle inflow cylinder (13) provided in the upper portion of the metering container (2). ) Is connected, and the compressed air (= air delivery air) ejected from the air pressure source (12) is measured.
Dry bed (11) and quantitative container (2) by blowing into (2)
The inside of the air-delivery line (14) that connects to and is depressurized, and the pre-expanded particles (1) in the dry bed (11) are air-delivered to the quantitative container (2).

(15) is a blowback cylinder, which is an idle line (14)
It is inserted into the particle inflow cylinder (13) of the metered-dose container (2) connected to, and is connected to the air pressure source (12) via the pressure throttle valve (15a).

The quantitative container (2) is arranged directly above the weight measuring device (3), and the bottom opening / closing device (5) is provided at the bottom of the quantitative container (2).
Is installed. Reference numeral (16) is an opening / closing drive device for the bottom opening / closing device (5). In addition, weigh the particles (1) that have been weighed
The particle weighing and discharging device (3) is equipped with a particle suction and discharging device (6) for discharging from the (3). The particle suction and discharge device (6) is also of the Venturi method, and the particles (1) that have been weighed are returned to the dry bed (11) again, and the blower (19) stores the pre-expanded particles (1) in the silo ( Shipped to 20). Of course, the measured pre-expanded particles (1) may be directly fed to the silo (20) without returning to the dry bed (11).

Between the bottom opening / closing device (5) at the bottom of the quantitative container (2) and the weighing container (3a) of the weight weighing device (3), and between the particle suction / discharge device (6) and the weighing container (3a). A space is provided in the container so that external force is not applied to the measuring container (3a). The silo is connected to a foam molding machine (not shown) so that foam molded articles can be continuously molded. The weighing device (3) is a weighing container (3a) and a weighing container.
(3a) is composed of a measuring unit (3b) arranged on the lower side, and the pre-expanded particles (1) are calculated by calculating the measuring result in the measuring unit (3b).
Calculate the specific gravity of and feed back.

Then, the pre-expanded particle feeding device (4) is operated to dry-feed the dried pre-expanded particles (1) discharged to the dry bed (11) to the quantitative container (2). The pre-expanded particles (1) are loaded into the fixed quantity container (2) by riding on the empty air, and the empty air is discharged from the air vent of the fixed quantity container (2).
At this time, the particle size of the pre-expanded particles (1) is mixed to some extent with various sizes, but the quantitative container is loaded on the air to be fed.
Since it is filled in (2), it will be filled while being evenly stirred during filling, and a bridge due to particle diameters will occur in the metering container (2) and a cavity will occur inside. There is no such thing. In this way, the pre-expanded particles (1) are filled in the quantitative container (2).

When the filling of the pre-expanded particles (1) into the fixed quantity container (2) is completed, the blow-back is activated, and the compressed air is ejected from the blow-back cylinder, and the extra pre-expanded particles (1 ) Is pushed back to the dry bed. In this way, when the fixed volume of pre-expanded particles (1) was filled in the fixed quantity container (2), the bottom opening / closing device (5) at the bottom of the fixed quantity container (2) was opened, and the fixed quantity container was opened. Pre-expanded particles in (2)
(1) is put into the weighing container of the weight weighing device (3) arranged immediately below.

When the pre-expanded particles (1) are put into the measuring container, the measurement is started, and the pre-expanded particles (1) in the measuring container (3a) are started.
The specific gravity is calculated and printed out, and the measurement result is fed back to the control device of the foaming tank (B), and if it is out of the predetermined pre-foaming ratio width, adjustment is made. As a method for adjusting the pre-expansion ratio, the supply amount of high temperature steam is controlled, and the supply amount of the raw material particles (1a) is controlled by controlling the screw (10) of the raw material supply cylinder (9),
There is a method of doing this by raising and lowering the height of the pre-expanded-particles discharge tube (18) of the foaming tank (B) by means of an elevation cylinder (17).

Changing the pre-expansion ratio by raising and lowering the discharge tube (18) means that the longer the raw resin (1a) stays in the foaming tank (B), the longer it is in contact with the high temperature steam. Becomes longer and the expansion ratio becomes higher. If the discharge tube (18) descends and discharges the pre-expanded particles (1) earlier, the one having a lower expansion ratio will be sent to the dry bed (11), and conversely the discharge tube (18) will rise and become slower. If the pre-expanded particles (1) are discharged, then those having a higher expansion ratio will be sent to the dry bed (11), and the expansion ratio can be adjusted.

When the measurement of the specific gravity of the pre-expanded particles (1) is completed in this way, the particle suction / discharge device (6) operates to suck and discharge the pre-expanded particles (1) in the measuring container (3a) by the Venturi method. And send it to the silo by air.

Since the supply / discharge of the pre-expanded particles (1) is performed by the air-feeding means as described above, the automatic magnification measuring device (A) for the pre-expanded particles (1) may be placed around the air-delivery line. It can be installed anywhere if possible, and it does not take up space because the fixed quantity container (2) is located directly above the weight measuring device (3).

[0024]

According to the present invention, since the pre-expanded particles are fed in the suction air so that the pre-expanded particles can be stored in the metering container, the metering container is formed in a cage shape. The pre-expanded particles can be supplied to the quantitative container by the air feeding means, and moreover, when the pre-expanded particles are filled in the quantitative container, each particle is evenly loaded by the air-feeding. Since it is not a mechanical filling method as in the prior art, there is an advantage that a thing like a bridge does not occur, the filling is not dense and dense, and the filling is always performed in a constant volume.

Further, since the quantitative container is arranged right above the weighing container of the weight measuring device and the bottom opening / closing device is installed at the bottom of the quantitative container, the pre-expanded particles quantified when the bottom opening / closing device is opened are There is no need to worry that the pre-expanded particles adhere to and remain in the corners of the metering container as in the past, and the pre-expanded particles do not enter the metering container. In addition to providing sufficient reliability, there is an advantage that the installation space can be saved by arranging the fixed quantity container and the weight measuring device vertically.

In addition to this, the weight measuring device is equipped with a particle suction / exhaust device for discharging the measurement completed particles from the weight measuring device. Can be done by air delivery,
There is also an advantage that the automatic magnification measuring device for pre-expanded particles of the present invention can be installed at any place where an idle line can be drawn, and it is not necessary to select an installation place.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of an automatic magnification measuring device and a foaming tank of the present invention.

FIG. 2 is a sectional view of a conventional automatic magnification measuring device and a foaming tank.

[Explanation of symbols]

(A)… Automatic magnification measuring device (1)… Pre-expanded particles (2)… Quantitative container (3)… Weighing device (4)… Pre-expanded particles emptying device (5)… Bottom opening / closing device (6)… Particles Suction discharge device

Claims (4)

[Claims] 1. Pre-foaming comprising a quantitative container for accommodating a fixed amount of pre-expanded particles to measure the volume of the pre-expanded particles, and a weight measuring device for measuring the weight of the pre-expanded particles quantified by the quantitative container. The automatic magnification measuring device for particles is equipped with a pre-expanded particle emptying device for allowing pre-expanded particles to be placed in empty air to be stored in the quantitative container, and is composed of a quantitative container with an air vent Automatic magnification measuring device for pre-expanded particles, which is characterized. 2. Preliminary foaming comprising a quantitative container for accommodating a fixed amount of prefoamed particles and measuring the volume of the prefoamed particles, and a weight measuring device for measuring the weight of the foamed particles in the container quantified by the quantitative container. An automatic magnification measuring device for pre-expanded particles, characterized in that in the automatic particle magnification measuring device, the quantitative container is arranged immediately above the weight measuring device, and a bottom opening / closing device is installed at the bottom of the quantitative container. 3. The automatic magnification measuring device for pre-expanded particles according to claim 1 or 2, wherein the weight measuring device is equipped with a particle suction / discharge device for discharging the measurement completed particles from the weight measuring device. Automatic magnification measuring device for pre-expanded particles. 4. The automatic expansion-measuring device for pre-expanded particles according to claim 1, 2 or 3, wherein the measurement result is fed back to the expansion tank and the expansion ratio is controlled to fall within a predetermined expansion ratio range. Automatic magnification measuring device for pre-expanded particles, which is characterized.