JPH06220240A - Pre-expander - Google Patents

Abstract

PURPOSE:To obtain a pre-expander for a foamable resin adapted so that the expansion ratio may be corrected at once by changing the metering value of feed pellets according to the deviation when the signal sent from a metering device is compared with the set value, and the sent signal is outside the tolerance range of the set value. CONSTITUTION:A feed metering hopper 8B is provided above a pre-expander body 2 for pre-expanding foamable resin pellets; a feed metering device 8F is provided on the feed metering hopper 8B; a bottom closing device 8C is provided on the bottom of the feed metering hopper 8B; a pre-expanded particle metering device 5 is provided adjacent to the pre-expander body 2 and meters the pre-expanded particles sent from the pre-expander body 2; the signal of the pre-expanded particles sent from the pre-expanded particle meter 5 is compared with the set expansion ratio in a controller 6; and when the sent value of the pre-expanded particles is outside the tolerance range of the set value, the feed rate of the feed is increased or decreased according to the deviation from the tolerance range by means of the feed metering device 8F.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prefoaming device for a foamed resin which can always keep the prefoaming ratio constant by constantly detecting the foaming ratio and feeding it back.

[0002]

2. Description of the Related Art A prefoaming device is a device for preliminarily foaming resin particles to be supplied to a foam molding machine at a predetermined ratio. The prefoamed resin particles are stored in a silo and aged. Supplied to a foam molding machine. In order to keep the foamed state in the foam molding machine constant and continuously produce a homogeneous foamed resin product, it is important that a certain amount of pre-expanded particles be continuously supplied to the foam molding machine.

In the conventional pre-foaming machine, as a method of setting the pre-foaming ratio, a method of setting a foaming time with a fixed timer or a photoelectric sensor fixedly installed in the main body of the pre-foaming machine is used. There is a method of completing the foaming when the foamed particles are detected. In the case of the former method, the time setting by the timer is fixed, and in the case of the latter, the height of the photoelectric sensor is fixed, so if there is a variation in the prefoaming ratio, it is possible to correct it to a predetermined ratio. There was a problem that it took a very long time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the drawbacks of the conventional example, and the purpose thereof is to compare a weighing signal from a weighing device with a set value,
An object of the present invention is to provide a pre-expansion device for a foamed resin in which the amount of raw material input is changed according to the deviation width when the measurement signal is out of the allowable range of the set value so that the expansion ratio can be immediately corrected.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned problems, a prefoaming device (A) for foaming resin according to claim 1 is a prefoaming machine main body for prefoaming foamed resin pellets.
(2), the input raw material measuring hopper (8B) provided on the raw material receiving section (8E) of the pre-foaming machine main body (2), and the input raw material measuring device (8F) attached to the input raw material measuring hopper (8B). ) And a bottom opening / closing device (8C) provided at the bottom of the input raw material weighing hopper (8B) for opening and closing the bottom of the input raw material weighing hopper (8B), and pre-expanded particles sent from the pre-expanding machine body (2). The pre-expanded-particle measuring device (5) for measuring the pre-expanded-particle measuring signal (5) and the pre-expanded-particle measuring signal from the pre-expanded-particle measuring device (5) are compared with the set expansion ratio, and the pre-expanded measured value indicates the allowable value of the set value. If it exceeds the limit, it is characterized by being configured with a control device (6) for increasing or decreasing the amount of raw material measured by the input raw material measuring device (8F) according to the deviation from the allowable value.

As a result, the pre-expanded particles of the main body of the pre-expanding machine (2) are weighed each time to calculate the expansion ratio, and if the expansion ratio is outside the allowable range of the set expansion ratio, the input raw material is made to correspond to the deviation width. The metering device (8F) can be used to increase or decrease the amount of raw material to correct the ratio, which makes it possible to control the expansion ratio very strictly and accurately, and to improve the quality of the final foamed molded product. There are advantages.

[0007]

The present invention will be described in detail below with reference to the illustrated embodiments. The main body of the pre-foaming machine (2) has a cylindrical heating cylinder (7) having a spherical bottom, a charging raw material supply section (8) and a heating cylinder (8) installed on the ceiling of the heating cylinder (7). It is composed of a drive unit (10) for driving a rotary blade (9) installed inside the unit (7). A steam pipe (11) and the drive device (10) are installed at the bottom of the heating cylinder (7), and steam is sent from the bottom into the heating cylinder (7) and the rotary blades (9) are rotated. You can do it.

(12) is an on-off valve installed in the steam pipe (11), which is controlled by the control device (6),
(20) is a pressure gauge installed in the heating cylinder (7).

A bottom plate (13) having a large number of pores (14) is installed at the bottom of the heating cylinder (7) so that high temperature steam can flow into the interior through the pores (14). ing. Drive (10)
Is connected to a rotary shaft (15) installed at the center of the heating cylinder (7) and rotates the rotary blade (9). A plurality of rotors (9) are installed on the rotating shaft (15), and the heating cylinder (7)
It is designed to rotate between the fixed wings (16) that are suspended inside.

Reference numeral (21) is an opening / closing device installed on the bottom side surface of the heating cylinder (7), and reference numeral (22) is a dry bed for drying connected to the opening / closing device (21). Of course, the present invention is not limited to this, but the opening / closing device (21) uses an opening / closing cylinder in this embodiment.

The dry bed (22) is provided with a floor plate (23) having a large number of pores (14) at its bottom, so that dry air supplied from the bottom is blown into the bed (22). Has become.

(5) is a pre-expanded-particle measuring device, which is composed of a pre-expanded-particle storing basket (5A) and a pre-expanded-particle measuring main body (5B) installed directly below the basket (5A). The cross section (5A) is connected to the bottom of the dry bed (22), and the storage section (5C) of the pre-expanded-particle measuring main body section (5B) is connected to the ceiling of the dry bed (22).

(6) is a control device, which is a pre-expanded-particle measuring main body
Connected to (5B) and installed on the side of the pre-foaming machine main body (2) and the measurement signal of the main body (5B) of pre-expanded granules, and the side of the main body of the pre-foaming machine (2) completes the foaming of the foaming resin inside. A bubbling completion detection signal or the like from the detection device (4) for detecting is detected. Further, the control device (6) is connected to the on-off valve (12) and the input material measuring device (8F) described later. (T)
Is a timer installed in the control device (6).

Reference numeral (8) is a charging raw material supply section installed on the ceiling of the heating cylinder (7), and the charging raw material supply section (8) is arranged directly below the raw material measuring section (8G). Raw material receiving unit (8
E) and. The raw material measuring section (8G) supports the input raw material measuring hopper (8B) and the input raw material measuring hopper (8B), and measures the input raw material supplied to the input raw material measuring hopper (8B) (8F). ) And a bottom opening / closing device (8C) installed at the bottom of the input raw material weighing hopper (8B) for opening and closing the bottom of the input raw material weighing hopper (8B). As the input raw material measuring device (8F), for example, a load cell or the like is used. The raw material receiving part (8E) is installed on the ceiling of the main body of the pre-foaming machine (2), and it receives the input raw material (8A) and the input raw material.
It is composed of a bottom opening / closing device (8D) for the main body provided at the bottom of (8A), and supplies the raw material resin pellets (1) measured by the raw material measuring section (8G) to the heating cylinder (7). It is like this.

Then, the raw material pellets (1) are supplied to the input raw material measuring hopper (8B), and the weight of the raw material pellets (1) is measured by the input raw material measuring device (8F). The measured value of the raw material pellets (1) is preset by the control device (6). When the pre-foaming of the previous lot is completed and the pre-foamed particles are discharged from the main body of the pre-foaming machine (2), the bottom opening / closing devices (8C) (8D) are opened to reserve the raw material resin pellets (1) that have been weighed. Supply to the foamer body (2). The input raw material receiver (8A) is simply a guide for the measured raw material pellets (1), and the bottom opening / closing device (8C) (8D)
Are designed to open and close in synchronization. The supplied resin pellets (1) are pre-foamed by the pre-foaming machine body (2), and the raw material pellets (1) of the next lot are measured during this time. After pre-foaming is completed, dry bed (2
If the pre-expanded granules (1) are discharged into 2), the raw material measuring section
(8G) and the main body bottom opening / closing device (8D) are operated to supply the raw material pellets (1) of the next lot to the prefoaming machine main body (2), and the prefoaming operation is restarted.

The measured and input values of the raw material resin pellets (1) are appropriately selected depending on the type of resin, the type of foamed product and other conditions.

The pre-foaming machine main body (2) is supplied with high-temperature steam from the bottom and is installed in the heating cylinder (7).
By driving the (9) to rotate, the charged raw material resin pellets (1) are stirred while being heated. Fixed work (1
Effectively done by 6) and rotor (9). By this operation, the raw material resin pellets (1) gradually foam and increase in volume. The foaming of the pre-expanded particles proceeds to increase the volume thereof.

The supply time of steam is controlled by a timer (T) built in the control device (6), and when the timer (T) is up, pre-foaming is almost completed. Therefore, when the timer (T) is up, the foaming work is finished, and the opening / closing device (2) installed on the bottom side surface of the heating cylinder (7) is
1) is opened and the pre-expanded particles are put into the dry bed (22) to prepare for the next pre-expansion work.

When the foaming operation is completed, the opening / closing device (21) installed on the bottom side surface of the heating cylinder (7) is opened, and the pre-expanded particles are put into the dry bed (22). When it is put in the dry bed (22), it is quickly dried by the dry air supplied to the dry bed (22), and the pre-expanded particle storage basket (5
Part of it is sent by air to A). When the iron basket (5A) is fully filled, the bottom opening / closing door (5D) is opened, and the pre-expanded particles are put into the pre-expanded-particle measuring main body (5B) installed just below the nozzle basket (5A). Here, the weight of the pre-expanded particles is measured, and this pre-expansion measurement value is sent to the control device (6), and the volume measured by the cross basket portion (5A) is divided by the weight measured here to calculate the expansion ratio.

When the pre-foaming measurement is completed, the dry bed (2
It is returned by air to 2), and is pre-expanded in the dry bed (22) together with the pre-expanded particles, and then air-delivered to the next step, a silo. In the silo, several lots of pre-expanded granules that have been sent by air are stored and aged. On the other hand, if the expansion ratio calculated by the preliminary expansion machine measurement is within the allowable range of the set expansion ratio, the next pre-expansion work is started as it is. However, if it is outside the allowable range, the input raw material metering device (8F) is used according to the deviation width.
Change the weighing in the control device (6) and correct the magnification from the next lot.

That is, when it is determined that the foaming ratio is insufficient by comparing the pre-expansion measuring signal from the pre-expansion particle measuring device (5) with the measurement ratio inputted in advance to the control device (6). In the foaming work of the next lot, the control device (6)
In accordance with the command, the amount of raw material pellets (1) is reduced according to the deviation width. As a result, the amount of steam per unit weight of the raw material pellets (1) (to be exact, the amount of heat of the steam) increases, pre-foaming of the raw material pellets (1) is promoted, and the expansion ratio increases accordingly.

On the other hand, when the expansion ratio is excessive, the control unit (6) in the next lot increases the amount of the raw material pellets (1) in accordance with the deviation width, and the expansion ratio in the next lot is decreased. If it is difficult to adjust the expansion ratio simply by increasing or decreasing the raw material pellets (1), control the steam flow time with a timer (by increasing the steam flow time, the raw material pellets
The amount of heat for (1) increases and the prefoaming ratio increases. ), Steam flow rate control (By increasing the valve opening of the on-off valve (12) and increasing the flow rate of steam, the amount of heat to the raw material pellets (1) increases, and the pre-foaming ratio increases. ) Etc. can be used together. Further, a detection device (4) can be used together to ensure the stability of pre-foaming. In that case, the detection device (4) is provided on the side surface of the heating cylinder (7), and the completion of the foaming work is detected by the detection signal from the detection device (4).

The above-mentioned adjustment of the steam flow time may be carried out by an operator using an external input device to empirically change the raw material measured value in accordance with the deviation width. Alternatively, the optimum raw material weight corresponding to the deviation width may be input to the control device (6) in advance, and the raw material measurement value may be automatically corrected.

[0024]

The present invention compares the pre-foaming metering signal from the pre-foaming metering device with the set foaming ratio, and when the pre-foaming measured value exceeds the allowable value of the set value, the pre-foaming measured value is changed from the allowable value. Since the raw material measurement value is controlled in accordance with the deviation width of the raw material, the raw material measurement value can be adjusted in accordance with the deviation width, thereby adjusting the vapor amount per raw material pellet unit. Since the magnification can be corrected, the foaming ratio can be controlled very strictly and accurately, and the quality of the final foamed molded product can be improved.

[Brief description of drawings]

FIG. 1 is an overall flow chart of a pre-foaming device according to the present invention.

FIG. 2 is a control flowchart of the pre-foaming device of the present invention.

[Explanation of symbols]

(1)… Expanded resin pellets (2)… Preliminary foaming machine main body (4)… Detection device (5)… Preliminary foamed particle metering device (6)… Control device (8C)… Bottom opening / closing device (8E)… Feed material metering Hopper (8F) ... Input material metering device (11) ... Steam pipe (12) ... Open / close valve

Claims (1)

[Claims] 1. A prefoaming machine main body for prefoaming expanded resin pellets, a charging raw material measuring hopper provided on a charging raw material receiving section of the preliminary foaming machine main body, and a charging raw material measuring device attached to the charging raw material measuring hopper. And a bottom opening / closing device provided at the bottom of the input material measuring hopper for opening and closing the bottom of the input material measuring hopper, a pre-expanded particle measuring device for measuring the pre-expanded particles sent from the pre-expanding machine main body, and pre-expanding When the pre-foaming measurement signal from the particle measuring device is compared with the set expansion ratio and the measured value exceeds the allowable value of the set value, the input raw material measuring device is made to correspond to the deviation from the allowable value. And a control device for increasing or decreasing the amount of raw material to be charged by the pre-foaming device.