JPS62202210A - Preheating control system for granular material - Google Patents

Abstract

PURPOSE:To fix the supply temperature to an extruding machine of granular materials by controlling the temperature of a heater with the detection output of the exit temperature of a hot blast generator and controlling the number of revolutions of a blower with the detection output of the heat discharge temperature of a hopper. CONSTITUTION:The exit temperature of a hot blast generator 14 is measured by a hot blast temperature detector 3, and this detected temperature is inputted to a temperature controller 5, and the output signal of this controller 5 is inputted to a power adjustment controller 7. The controller 7 adjusts the supply power to an air heater 2. Meanwhile, the temperature of a heat discharge exit 12 of a hopper 9 is measured by a heat discharge temperature detector 4, and the output of this detected temperature is inputted to a temperature controller 6, and the output of the controller 6 is inputted to a controller 8 for the number of revolutions. The controller 8 outputs a control signal matched to the temperature set to the controller 6 to control the number of revolutions of a blower 1. Thus, the preheating temperature of granular materials 11 is always kept at a certain proper temperature if the quantity of blast of the blower 1 is controlled.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a preheating control method for granular objects, specifically, a method for preheating granular objects of plastic pellet caps used as insulation coverings for ultra-high voltage electric cables, etc. This relates to a preheating control method.

[Prior art] In order to apply an insulation coating to a wire conductor, the wire conductor is passed through an extruder for the insulation coating, and a granular object such as plastic svelette, which is the insulation coating, is placed in the hopper of the extruder. It is stored, preheated, and fed to an extruder to coat the wire conductor.

In this case, the granular material is preheated to a constant temperature before being supplied to the extruder. Conventionally, the temperature at which the granular material is supplied to the extruder is controlled by a hot air generator that sends hot air into the hopper. The temperature at the outlet is measured and controlled accordingly.

However, the preheating temperature of the granular material varies greatly due to changes in the speed of the extruder (including when it is stopped), ie, changes in the feeding tray of the granular material to the extruder.

Therefore, it is necessary to adjust the amount of heat supplied to the hopper as the extrusion m changes, but this has conventionally been done manually.

[Problems to be solved by the invention] However, relying on artificial means to appropriately adjust heat supply as in the past requires many years of skill based on a person's extensive experience and sensitivity. The drawback was that it was not something that anyone could do, and only a specific person could do it.

In order to overcome the above-mentioned drawbacks, it is an object of the present invention to automatically control the temperature of the granular material fed to the extruder, regardless of the speed at which the granular material passes through the hopper or the amount of the granular material. The purpose of the present invention is to provide a preheating control method that can maintain a constant temperature.

[Means and effects for solving the problem] In the present invention, the exhaust heat temperature of the hopper decreases as the extrusion supply amount of granular material increases, and decreases as the extrusion supply amount decreases. and a blower, detects the outlet temperature of the hot air generator that preheats the granular objects in the hopper, and controls the temperature of the heater based on the detected output, and
The exhaust heat temperature of the hopper, which changes depending on the amount of granular material in the hopper supplied to the extruder, is detected, and the rotation speed of the blower is controlled based on the detected output.

[Example] Hereinafter, an example of a control device to which the preheating control method of the present invention is applied will be explained with reference to the drawings.

A hot air generator 14 configured with a blower 1 and an air heater (heater) 2 uses the blower 1 to forcefully send air to the air heater 2, and the air heated there is sent to the hot air generator 14.
is fed into the hopper 9 from the outlet. This hopper 9 is disposed at the 42nd position of the extruder 10, and stores the granular objects 11 such as plastic pellets supplied from the granular object supply port 13 at the upper part, and the hopper 9 is used to store the granular objects 11 such as plastic pellets supplied from the granular object supply port 13 at the upper part. It serves to heat the object 11 and feed it to the extruder 10. In addition, the hot air sent into the hopper 9 is
The heat is not removed by the granular objects 11 housed in the hopper 9, and then exits to the outside through the exhaust heat outlet 12.

The outlet temperature of the hot air generator 14 is measured by a hot air temperature detector 3, and the detected temperature is inputted as a detection output from the detector 3 to the temperature controller 5. The output signal is input to the power adjustment controller 7. This controller 7 outputs a control signal commensurate with the set temperature of the regulator 5, and serves to adjust the power supplied to the air heater 2.

On the other hand, the temperature of the exhaust heat outlet 12 is also measured by the exhaust heat temperature detector 4, and the output of the detected temperature is input to the temperature regulator 6, and the output signal of the regulator 6 is used to control the rotation speed. It is input into the device 8.

This control device 8 outputs a control signal commensurate with the temperature set to the regulator 6 to control the rotation speed of the blower 1.

In the present invention configured in this way, in addition to measuring the outlet temperature of the hot air generator 14 and controlling the heating temperature of the air heater 2, the temperature of the exhaust heat outlet 12 is detected and the blower is controlled accordingly. The air flow rate of 1 is controlled. Above exhaust heat outlet 1
The temperature of No. 2 tends to decrease as the extrusion supply amount of the granular material 11 increases, and increases as the amount decreases. Therefore, by controlling the amount of air blown by the blower 1, the preheating temperature of the granular material 11 can always be maintained at a constant appropriate temperature.

Note that since the air volume control has a minimum air volume, it is set to output the minimum air volume even if a control signal lower than that is input.

In addition, if it is difficult to continuously detect the amount of granular material supplied to the extruder, the extruder screw (not shown) may be used.
The feed rate can be calculated as a percentage from the rotation speed of the blower, and this can be used as a signal to control the blower rotation speed.Furthermore, the feed rate of the granular material to the extruder can be determined by the waste heat temperature when the air is discharged from the hopper. Since you can know this, you can use this.

In other words, if the waste heat temperature increases, the amount of granular material supplied to the extruder will be small, and if it decreases, the amount of granular material supplied to the extruder will be large, and so it is possible to indirectly know the amount of granular material supplied to the extruder. Therefore, the rotation speed of the blower may be controlled by detecting this waste heat temperature.

[Effects of the Invention] As mentioned above, according to the present invention, the drawbacks of the conventional technology can be overcome, and the following remarkable effects can be achieved.

(1) Since the air volume is adjusted by controlling the rotation speed of the floor drive motor, for example, if the air volume becomes productive, the power will be halved.
3, resulting in energy savings.

(2) Can be easily applied to existing equipment.

(3) Continuous operation can be performed without changing the quality of granular objects.

(4) Since the system adopts a configuration that allows operation at a minimum air flow rate or lower, there is no danger of the air heater running dry.

[Brief explanation of drawings]

The figure is a diagram showing an example of the preheating control method of the present invention. 1...Blower 2...Air heater 3.4...Onmaro detector 9...Hopper 10...・Extruder 11... Granular objects (plastic pellets)
= 7-

Claims (1)

[Claims] A preheating control method for supplying granular objects stored in a hopper of an extruder to a constant temperature while preheating the granular objects to an extruder, comprising an air heater and a blower, the hopper means for detecting the outlet temperature of a hot air generator that sends hot air to preheat the granular objects in the hopper, and controlling the temperature of the heater based on the detected output; and supplying the granular objects in the hopper to the extruder. A method for preheating a granular object, comprising: means for detecting a temperature of exhaust heat from a hopper that changes depending on the quantity of heat, and controlling the rotation speed of the blower based on the detected output.