JPH0553619B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a hopper device for a plastic extruder, such as a wire coating extruder.

[Prior Art] Conventionally, in an extruder for extruding plastic, such as an extrusion coating device for electric wires, an extrusion material is supplied to a hopper port of the extruder, and the plastic is extruded from an extrusion head at the tip of a screw part. As shown in Fig. 2, this has an extrusion head B at the tip of the screw part A of the extruder, and an inverted conical shape above the hopper opening C communicating with the screw part A.
A service hopper D having an inverted pyramid shape or the like is installed, and a hopper loader E that continuously supplies plastic material is installed above it, and the plastic material is fed to this hopper loader E from a material supply hose F. In addition, a torque-type or capacitance-type level meter G is installed in the service hopper D in order to notify when an abnormality or shortage occurs in the supply of materials. was heated and softened in an extruder and extruded from an extrusion head B at the tip of the screw section A.

The plastic material supplied to the hopper is in the form of cylindrical or cubic pellets or powder particles with a diameter of 2 to 5 mm and a length of 0.5 to 5 mm. A hopper loader E supplies the plastic material to be colored or a material in which uncolored material and concentrated colored material are sufficiently mixed to the service hopper D, and extrudes it through the screw section A. To change the color of the hopper, all the material in the hopper was removed and then a new color of material was supplied.

In addition, as for extruding a mixture of pellets and flakes, as shown in Japanese Patent Application Laid-Open No. 57-93118, flakes obtained by cutting a collected resin film are stored in a flakes storage container,
The resin pellets are stored in a pellet storage container, the flakes in the flakes storage container are weighed with a gravimetric scale and fed to a hopper equipped with stirring blades, and the pellets in the pellet storage container are weighed with a gravimetric scale. It is known that the flakes and pellets are fed to a hopper equipped with stirring blades, the flakes and pellets are uniformly mixed in this hopper by the stirring blades, and the mixture is fed to a screw-type feeder to be sent to an extruder. There is.

In addition, as a hopper equipped with a level meter, as shown in Utility Model Application Publication No. 50-96666, a hopper having one raw material inlet at the upper end and multiple raw material outlet ports at the lower end is used. In addition to installing a level meter to detect the upper limit level of the raw material in the hopper, a timer is also installed.When the raw material in the hopper falls below the level of the level meter, the timer starts, and after a predetermined period of time, the raw material feed is stopped. There is a known solenoid valve at the inlet that opens and starts feeding the raw material into the hopper, and when the raw material in the hopper reaches the level of the level meter, the solenoid valve closes and stops the feeding of the raw material and the timer. There is.

[Problems to be Solved by the Invention] As mentioned above, in the conventional device, the inside of the hopper loader E has unevenness and the level meter G protrudes into the service hopper D, so there is no plastic material inside these parts. To change the color of the plastic being extruded, stop the operation of the wire coating extruder line and thoroughly clean the inside of the hopper to remove all the colored plastic material remaining from the previous process. The wire coating extruder line must be shut down for an extended period of time each time the color of plastic to be extruded is changed, and the extruder line must be shut down for an extended period of time. There was a problem that the rate decreased significantly.

In addition, in the method disclosed in the above-mentioned patent application publication, since the flakes and pellets are stirred by the stirring blade in the hopper, a large amount of material powder remains in the hopper, and when changing the material, There is a problem in that operation must be stopped for a long time in order to clean the inside of the hopper and completely remove residual material from the previous process, which reduces the operating rate.

Furthermore, since the flakes and pellets must be weighed using a weight scale before being fed to the hopper, there is a problem in that the weighing and feeding of the flakes and pellets does not proceed quickly.

Moreover, the one disclosed in the above-mentioned utility model application publication is configured so that the raw material is fed into the hopper by opening the solenoid valve of one raw material feed port at the upper end of the hopper without measuring the raw material. for,
There is a problem in that it is not possible to meter and feed predetermined amounts of each of two raw materials, such as color masterbatch and base pellets, to a hopper and extrude the mixture.

The present invention solves the above problems and improves the operating rate of the extruder line by making it possible to change the color of the extruded plastic in continuous operation without stopping the wire coating extruder line. The object of the present invention is to provide a hopper device for a plastic extruder.

[Means for Solving the Problems] In order to achieve the above object, the hopper device of the plastic extruder of the present invention is equipped with a metering device 8, and a service hopper 1 for supplying uncolored plastic material Pn and a colored plastic material. A plurality of service hoppers including service hoppers 2, 3, 4, etc. for supplying PC, and a transparent pipe 5 for feeding extruded material provided between the service hoppers and the hopper port 7 of the extruder. , and a light emitting/receiving type level meter 11 provided on the outside of the transparent pipe 5. The light emitting/receiving type level meter 11 detects the level of the plastic materials Pn and Pc inside the transparent pipe, and the measuring device 8 is controlled by the detection output. The plastic material in the service hopper is measured and supplied to the transparent pipe 5 by the measuring device 8 when the plastic material is operated.

[Function] Each weighing device 8 of the service hoppers 1 to 4 measures the uncolored plastic material Pn in the service hopper.
A predetermined supply amount of an extruded plastic material such as a plastic material Pn or a colored plastic material Pn is measured, and the measured plastic material is fed to a transparent pipe 5 for feeding the extruded material.

The plastic materials Pn and Pc fed to the extrusion material feeding transparent pipe 5 are fed to the hopper port 7 of the extruder. Transparent pipe 5 for feeding this extruded material
Since it does not have stirring blades like conventional ones, there is no residual plastic material powder in the pipe, so when changing the color of the plastic to be extruded, it is no longer necessary to operate the electric wire coating extruder line as in the conventional one. There is no need to stop the system for a long time, and the operating rate does not decrease.

Since this extruded material feeding transparent pipe 5 is transparent, the upper surface level of the plastic material fed inside can be seen from outside the pipe, and since light is transmitted, a projection provided on the outside of the transparent pipe is used. By emitting and receiving light from the light-receiving level meter 11, it becomes possible to detect the level of the plastic material inside.

By making the pipe 5 for feeding extruded material transparent and providing the light emitting/receiving type level meter 11 on the outside of the pipe, no protrusion is formed inside the pipe for feeding extruded material. Therefore, there is no residual plastic material in the pipe, and therefore, when changing the color of the extruded plastic, there is no need to stop the wire coating extruder line for a long time as in the past, and it is possible to continuously Operation becomes possible and there is no reduction in operating rate.

When the light emitting/receiving type level meter 11 detects the level of the plastic material in the transparent pipe, the detection output operates the measuring device 8, and the measuring device 8 measures the plastic material in the service hopper and feeds it to the transparent pipe. be done.

[Example] Fig. 1 shows an example of the present invention, in which A is a screw part of an extruder, B is an extrusion head, 1,
2, 3, and 4 are a plurality of service hoppers.
Reference numeral 5 designates a transparent pipe for feeding extruded material, the upper end of which is connected to the plurality of service hoppers 1, 2, 3, 4 through a flange portion 6, and the lower end of the pipe is connected to a hopper port 7 communicating with the screw portion A. Connect to.

Service hoppers 1, 2, 3, and 4 are filled with uncolored plastic natural material Pn in one or several service hoppers, and concentrated in one or several other service hoppers. One or several types of colored plastic color material Pc colored in an appropriate color are put therein. For example, a red color material is put in the service hopper 2, and a blue color material is put in the other service hopper 3. . A metering device 8 is provided at the bottom of each of these hoppers for metering a fixed amount of plastic material and delivering it to the transparent pipe 5.

The measuring device 8 provides a hole at an eccentric position of the rotary disk, forms the inside of this hole to a predetermined volume, and rotates the plastic material grains in the hopper into the hole of this volume so that the plastic material particles on the transparent pipe 5 are carry it to the opening,
The material particles are fed into the transparent pipe 5 from the opening at the bottom of the hopper, and the amount of plastic material is automatically measured and supplied to a predetermined amount depending on the volume of the hole into which the material particles are placed. .

Further, a hopper loader 9 for continuously supplying the natural material Pn is installed above the service hopper 1 into which the uncolored plastic natural material Pn is fed, and the material is fed through a supply hose 10.

The transparent pipe 5 for feeding extruded material transports a fixed amount of plastic material supplied from each service hopper 1, 2, 3, 4 to the screw section A.
This serves as a passage for feeding the plastic material to the hopper port 7 of the plastic material, and is made of a transparent hollow pipe without any protrusions or irregularities or joints that would stagnate the flow of plastic material inside the pipe.

A light emitting/receiving type level meter 11 using a photoelectric switch or the like is installed outside the transparent pipe 5. This light emitting/receiving type level meter 11 emits light with a light emitter on one side outside the transparent pipe 5 and receives the light on the other side, or emits light with a light emitter/receiver from one side outside the transparent pipe 5 and receives the light on the other side. The reflected light is reflected by a reflecting mirror and received by the original emitter/receiver, and this emitter/receiver type level meter 1
1, the position level of the plastic material contained in the transparent pipe 5 is detected, and the measuring device 8 of each service hopper 1, 2, 3, 4 is operated by the output signal.

In addition, each of the above service hoppers 1, 2, 3,
4. The flange portion 6, hopper opening 7, measuring device 8, etc. should be free of irregularities and joints that would stagnate the flow of plastic material, and the accuracy with which the measuring device 8 measures the amount of plastic material should be ,
In order to avoid color unevenness in the extruded colored plastic, the variation in the difference between the maximum and minimum amounts to be measured should be no more than 10% of the minimum amount.

The device of the present invention configured as described above first has the following features:
When there is no plastic material in the first transparent pipe 5, the level meter 11 detects this and starts the desired metering device 8 of the service hopper 1, 2, 3, 4. For example, when extruding plastic colored red, start the weighing device 8 of the service hopper 1 containing the natural material Pn of uncolored plastic, measure out a certain amount, and send out the colored plastic. The measuring device 8 of the service hopper 2 containing the material Pc is started to measure and send out a fixed amount, and this is repeated alternately to alternately add a fixed amount of uncolored natural material Pn and colored material Pc to the transparent pipe 5. to be sent to. As a result, the uncolored natural material Pn and the colored material Pc are alternately fed into the transparent pipe 5 as shown in the figure and are deposited on top of each other, raising the level of the upper surface of the plastic material within the transparent pipe 5.

When the light emitting/receiving type level meter 11 detects this increased plastic material level, the above-mentioned started measuring device 8 is stopped.

The uncolored natural material Pn and the colored material Pc fed into the transparent pipe 5 are fed to the screw section A, kneaded into a uniformly colored plastic, and extruded from the extrusion head B.

When the amount of plastic material in the transparent pipe 5 decreases due to this extrusion and its level drops, the light emitting/receiving level meter 11 detects this decreased level again and starts the metering device 8 of the service hopper. Uncolored natural material for pipe 5
Pn and color material Pc are fed. In this way, colored plastic is continuously supplied.

If you want to change the color of the extruded plastic,
For example, to change it to blue, when changing it,
The measuring device 8 of the service hopper 2 containing the red coloring material Pc is stopped, and the measuring device 8 of the service hopper 3 containing the blue coloring material is operated instead to supply and extrude as described above. I do. In this way, the supply of coloring material can be changed to blue and extrusion can be performed continuously without stopping the operation of the extruder.

The above-mentioned service hopper is an example in which four service hoppers are installed in the illustrated embodiment, but the type of color,
It is installed and used by increasing or decreasing the amount as appropriate depending on the amount of materials to be supplied.

[Effects of the Invention] As described above, the extrusion material supplying transparent pipe provided between the service hopper and the hopper opening of the extruder is transparent and transmits light. It is now possible to install a meter to detect the level of plastic material in the pipe,
For this reason, there is no protrusion such as a level gauge formed inside the pipe that would obstruct the feeding of plastic material as in the prior art, so no plastic material remains.

Furthermore, since this pipe for feeding extruded material does not have stirring blades inside, there is no possibility that plastic material powder is generated due to stirring and remains inside the pipe as in the conventional method.

Therefore, when changing the type or color of plastic material, there is no need to stop the operation for a long time and clean up the remaining plastic material powder, which is the time-consuming work that was done in the past. This makes it possible to change the operating rate, thereby preventing a decrease in the operating rate.

Furthermore, since the transparent pipe for feeding extruded material is transparent, it is possible to monitor the condition of the internal plastic material from outside the pipe.

Furthermore, since there are no protrusions formed inside the extrusion material feeding transparent pipe that would impede the flow of the material, the plastic material can be fed smoothly and the plastic material can be colored uniformly without uneven coloring. Can extrude plastic.

In addition, a service hopper with a metering device for each feed material has been installed, allowing users to change the color or type of plastic to be extruded coated without stopping the wire coating extrusion line. The color and type of the extruded coated plastic are changed by operating the metering device of the desired service hopper in accordance with the detection output of the meter, which prevents a drop in the operating rate of the extruder and reduces the supply of material. It is possible to detect the state and automatically control the supply amount.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, and FIG. 2 is a diagram showing a conventional device. 1-4: Service hopper, 5: Transparent pipe,
8: Measuring device, 11: Light emitting/receiving type level meter.

Claims (1)

[Claims] 1 a plurality of service hoppers equipped with measuring devices and supplying uncolored plastic materials and colored plastic materials; a transparent pipe for feeding plastic materials provided between the service hoppers and the hopper opening of the extruder; A light emitting/receiving type level meter provided on the outside of the transparent pipe is provided, and the level of the plastic material in the transparent pipe is detected by the light emitting/receiving type level meter, and the measuring device is operated based on the detected output, and the measuring device is operated. A hopper device for a plastic extruder, characterized in that the device measures the plastic material of the service hopper and feeds it to the transparent pipe.