JPH0493222A - Removing method and device for metallic foreign matter mixed into pelletlike insulation material - Google Patents

Abstract

PURPOSE:To suspend feed of a pelletlike insulation material of a part into which a metallic foreign matter is contained without suspending a production line of an electric wire and cable, by a method wherein high frequency is applied to a pelletlike insulation material to be conveyed, a metallic foreign matter mixed into the material is detected by light or a sound emitted by the metallic foreign matter and the material around the detected place is removed during conveyance. CONSTITUTION:When a pelletlike insulation material 2 which is sent by air with a conveying device 4 comes to a high-frequency irradiation chamber 7 and a metallic foreign matter is mixed into the material 2, light and a sound are emitted by a part of the metallic foreign matter and detected by a detector 8. A valve opening and closing control device 11 turns a directional control valve 10 into an open state by a detected signal after the lapse of time which has taken a moving speed of the material 2 and a distance of the material 2 to the directional control valve 10 into consideration, an inlet of a discharge path 9 is opened and a conveying path 32 is closed. Then the pelletlike insulation material 2 containing the metallic foreign matter is discharged outside and removed from the conveying path 3. Then after the lapse of an appropriate time (sufficient time to discharge the pelletlike insulation material 2 containing the metallic foreign matter outside), the directional control valve 10 is made into a closed state.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to pellet-shaped insulating materials used in manufacturing insulators used in high electric fields, such as insulators for high-voltage C cables. In particular, when the pellet-shaped insulating material contains metallic foreign matter, removing the pellet-shaped insulating material containing the metallic foreign matter during transportation can remove the metallic foreign matter from wires and cables. A method for removing metallic foreign matter mixed into pellet-like insulating material that can prevent the supply of pellet-like insulating material containing metallic foreign matter without stopping the production line, and a method for removing metallic foreign matter mixed into pellet-like insulating material. The present invention relates to a foreign matter removal device.

[Prior art 1] In recent years, excellent synthetic resins have become available at low cost and are widely used in general household goods, home appliances, and the like. In particular, synthetic resins such as polyethylene resin and vinyl chloride resin are widely used as coating materials for insulated wires, cables, etc. because of their good insulation performance.

Generally, insulated wire cables are manufactured by continuously supplying synthetic resin material formed into pellets from a hopper or the like, melting the pellets under heat, and extruding the pellets using an extrusion molding machine.

Foreign matter may be mixed into the insulator of the insulated wire cable manufactured in this manner. This foreign material was mixed into the pellet, and it is necessary to detect and remove the pellet containing the foreign material before extrusion. There are various types of foreign substances, and they may be metals such as copper and iron. When pellets containing such metallic foreign matter are used as cable insulators, electrical performance is degraded. Particularly in high voltage Cv cables (crosslinked polyethylene electric cables) used in high electric fields, it has been reported that even metallic foreign matter of several tens of micrometers significantly reduces the breakdown voltage value.

Therefore, in order to prevent metallic foreign matter from entering insulators used under high electric fields such as high voltage Cv cables, it is necessary to check whether metallic foreign matter is mixed into the insulating material formed in the form of pellets. If a metallic foreign substance is detected in advance, it is necessary to remove it.

Conventionally, metal detectors have been widely used to detect metallic foreign substances present in pellets of such insulating materials. This metal detector uses a coil to create a high-frequency magnetic field in advance, places a test object (insulating material formed in the form of a pellet) in this magnetic field, and when a metallic foreign object is present, the disturbance in the magnetic field occurs. This method detects metallic foreign objects by using the induced voltage in the receiving coil generated by the receiving coil.

However, the ability of this metal detector to detect metallic foreign objects is limited to the detection of metal balls with a diameter of about 100 μm, and metal foreign objects smaller than this cannot be detected, so this metal detector is insulated. When the material pellets are put into a pneumatic feed line, the ability to detect metallic foreign objects is further reduced, and only metal balls with a diameter of about II or more can be detected.

It has been known that high-frequency discharge occurs in a conductive substance when it is present in a high-frequency electric field. I have often experienced this kind of phenomenon occurring in Kotops, etc.

In recent years, as a method for detecting metallic foreign matter mixed into glass fibers or glass fiber processed products,
No. 214748, Japanese Patent Application Laid-open No. 60-67844,
JP-A-60-144647, JP-A-60-196
A device for detecting a conductive substance using high frequency waves as shown in Japanese Patent No. 694 has been developed. In all of the conductive substance detection devices disclosed in these publications, a high-frequency irradiation chamber for irradiating high-frequency waves is prepared in advance, and a test object (glass fiber or glass fiber processed product) is placed in this high-frequency irradiation chamber. This method attempts to detect the presence of metallic foreign matter by detecting light or sound generated by high-frequency discharge of a conductive material portion when a metallic foreign matter (conductive material) is present.

[Problems to be Solved by the Invention] However, when a conventional metal detector is inserted into a pneumatic feeding line for pellets, which are insulating materials, the ability to detect metallic foreign objects is about 1111 in diameter, and is only several tens of μm in diameter. The high voltage Cv that a degree of metallic foreign matter greatly reduces the breakdown voltage value
A highly accurate device is required for detecting metallic foreign substances contained in pellet-shaped polyethylene resin used as a cable insulator.

The insulator of the high-voltage Cv cable is formed by continuously air-feeding polyethylene resin formed into pellets into a hopper, melting it in an extruder, and extrusion coating it onto a running wire. Normally, electric cables have a fixed length, and the line cannot be stopped during production. Furthermore, if the system stops, it requires a great deal of time and effort to restart it.

Therefore, even if metallic foreign matter is present in the pellet-shaped polyethylene resin, the production line cannot be stopped. The conventional method of detecting metallic foreign matter mixed into glass fibers or glass fiber processed products using high frequency waves is to create a high frequency irradiation chamber in advance to irradiate high frequency waves, and then to place the finished product inside the high frequency irradiation chamber. It is configured to insert and detect glass fibers or glass fiber processed products. Therefore, when a metallic foreign substance mixed in glass fiber or a glass fiber processed product is detected, the object to be inspected is stopped or a mark is placed at the detected location, and then this portion is removed in a subsequent process. However, if this method detects metallic foreign matter mixed into the pellet-shaped synthetic resin material that is continuously transported during cable manufacturing, the supply of pellets must be stopped and the production line must be stopped. The problem is that it does not.

The present invention uses pellet-shaped! If the edge material contains metallic foreign matter, pellets containing metallic foreign matter! A method for removing metallic foreign matter mixed into pellet-like insulating material that can prevent the supply of pellet-like insulating material containing metallic foreign matter by removing edge material during transportation, and a method for removing metallic foreign matter mixed into pellet-like insulating material. The purpose of the present invention is to provide a device for removing metallic foreign matter.

[Means for Solving the Problems] In order to achieve the above object, the method of removing metallic foreign substances mixed in pellet-shaped insulating material according to the present invention is to melt and extrude a synthetic resin material to coat a running wire in the form of pellets. During the process of transporting insulating material for electric wires and cables through a transfer line, the pellet-shaped insulating material being transported in the transfer line is irradiated with high frequency waves, and this occurs when metallic foreign objects mixed into the pellet-shaped insulating material pass through. The metallic foreign matter is detected by light or sound, and the pellets of insulating material before and after the detected metallic foreign matter are removed during transportation of the pelletized insulating material, thereby preventing the metallic foreign matter from being mixed into the pellet #@ edge material. This prevents the transport of foreign metallic objects.

In addition, in order to achieve the above object, the present invention provides a device for removing metallic foreign matter mixed into pellet-shaped insulating material, which is a pellet-shaped insulating material that is melt-extruded and coated with a synthetic resin material to form an insulator for electric wires and cables. On the conveyance path that conveys
A high-frequency irradiator that irradiates high-frequency waves to the pellet-shaped insulating material moving within the conveyance path, and light or sound accompanying high-frequency discharge generated in metallic foreign matter mixed into the pellet-shaped insulating material by the high-frequency irradiation by the high-frequency irradiator. In addition, a discharge passage for discharging the pellet-shaped insulating material is provided at an appropriate location on the downstream side in the conveyance direction from the installation position of the high-frequency irradiator on the conveyance passage, and at the entrance of this discharge passage,
A switching valve is provided that receives a detection signal from the detector and switches between a conveyance path and a discharge path, and a valve opening/closing control device that controls the switching valve by detecting light or sound by the detector is provided, When light or sound is detected by the device, the switching valve is opened and the pellet-shaped insulating material mixed with metallic foreign matter is carried out from the discharge path.

[Function] In the process of conveying pellet-shaped insulating material for electric wires and cables, which is melted and extruded from synthetic resin material and coated on running wires, in a transfer line, high frequency waves are irradiated to the pellet-shaped insulating material being conveyed in the transfer line. The metallic foreign matter is detected by the light or sound generated when the metallic foreign matter mixed in the pellet-shaped insulating material passes through, and the pellet-shaped insulating material before and after the pellet-shaped insulating material where the metallic foreign matter is detected is pelletized. Since the insulating material is removed during transportation, if the pellet-shaped insulating material contains metallic foreign matter, the part containing the metallic foreign matter can be removed without stopping the electric wire/cable production line. Pellet #4
! The supply of AS material can be stopped.

In addition, a high-frequency irradiator is installed on the conveyance path that conveys the pellet-shaped insulating material, which is melt-extruded and coated with a synthetic resin material to form the insulation of electric wires and cables, and is equipped with a high-frequency irradiator that irradiates high-frequency waves to the pellet-shaped insulating material that moves within the conveyance path. and a detector for detecting light or sound accompanying high-frequency discharge generated in the metallic foreign matter mixed into the pellet-like Mll material by high-frequency irradiation by the high-frequency irradiator, and a position where the high-frequency irradiator is installed on the conveyance path. A discharge path for discharging the pellet-like insulating material is provided at an appropriate location on the downstream side in the conveyance direction, and a switching valve is provided at the entrance of the discharge path to receive a detection signal from the detector and switch between the conveyance path and the discharge path. , a valve opening/closing control device is provided that drives and controls the switching valve based on the detection of light or sound by the detector, and drives the switching valve when light or sound is detected by the detector to prevent the contamination of metallic foreign matter. Since the pelletized insulating material is carried out to the outside through the discharge path, if the pelletized insulating material contains metallic foreign matter, it can be removed without stopping the electric wire/cable manufacturing line. It is possible to stop supplying only the pellet-shaped insulating material of the part containing the material.

[Example] Examples of the present invention will be described below.

FIG. 1 shows an embodiment of the first invention and the second invention.

In the figure, 1 is a device for removing metallic foreign matter.

Reference numeral 2 is a pellet-shaped insulating material formed into a pellet to serve as an insulator when forming an insulator for electric wires and cables by melt-extruding a synthetic resin material.

Reference numeral 3 denotes a conveyance path which continuously conveys and supplies the pellet-shaped insulating material 2 in the direction of arrow A at a predetermined speed to a hopper which melts and continuously supplies the pellet-shaped insulating material 2 to an extrusion molding machine (not shown).

4 is a predetermined amount of pellet-shaped insulating material 2 in the conveying path 3;
This conveying device 4 is a conveying device that conveys at a predetermined speed, and this conveying device 4 pressure-feeds the pellet-shaped insulating material 2 into the conveying path 3 together with air.

5 is a high frequency irradiator, which uses a high frequency oscillator to generate 2500
A high frequency wave having a frequency of around MHz is oscillated and is irradiated onto the pellet-shaped insulating material 2 being conveyed within the conveying path 3 via the waveguide 6. As the high-frequency oscillator of this high-frequency irradiator 5, a magnetron or the like with a frequency of several thousand MHz and an output of several hundred W is used.

Reference numeral 7 constitutes a high-frequency irradiation chamber, which is formed by a high-frequency irradiator 5, a waveguide 6, and a transport path 3.

8 is a detector which detects light or sound generated by high frequency discharge. When the pellet-shaped insulating material 2 is irradiated with high-frequency waves by the high-frequency irradiator 5, a high-frequency electric field is created. The electric field concentrates on the foreign object, producing a high-frequency discharge. When high-frequency discharge occurs, light and sound are emitted from the metallic foreign object. The detector 8 detects the light or sound generated by this high frequency discharge. Although one detector 8 may be used, it is preferable to provide a plurality of detectors (four in this embodiment) in order to improve detection accuracy. As the detector 8, a photodiode or the like is used to detect light generated by high-frequency discharge, and a microphone or the like is used to detect sound generated by high-frequency discharge.

Reference numeral 9 denotes a discharge path connected to the conveyance path 3. This discharge path 9 is provided on the downstream side in the conveyance direction of the pellet-shaped insulating material 2 from the position where the high-frequency irradiator S is installed, and is designed to remove metallic foreign matter. This is for discharging the pellet-shaped insulating material 2 from the conveyance path 3 to the outside.

Reference numeral 10 denotes a switching valve, which is installed at the entrance of a discharge path 9 connected to the conveyance path 3. In order to
As shown by arrow B in the figure, the conveyance path 3 is switched to the discharge path 9, or from the discharge path 9 to the conveyance path 3.

Reference numeral 11 denotes a valve opening/closing control device, which controls the opening/closing operation of the switching valve 10 for discharging the pellet-shaped insulating material 2 containing metallic foreign matter from the conveyance path 3 based on the detection of light or sound by the detector 8. It is for controlling. That is, the detector 8
When it is detected that metallic foreign matter is contained in the pellet-shaped insulating material 2, the valve opening/closing control device 11 is activated, controls the opening/closing operation of the switching valve 10, and adjusts the moving speed of the pellet-shaped insulating material 2. After a period of time that takes into account the distance to the switching valve 10, the switching valve 10 is opened (the entrance of the discharge path 9 is opened).
Then, the inlet of the discharge path 9 is opened and the conveyance path 3 is closed. Then, the pellet-shaped insulating material 2 containing the metallic foreign matter is discharged to the outside and removed from the conveyance path 3. As a result, the pellet-shaped insulating material 2 that had been air-fed through the conveyance path 3 until now
is discharged to the outside through the discharge path 9.

In addition, after opening the switching valve 10 (opening the inlet of the discharge passage 9), the valve opening/closing control device 11 operates for an appropriate period of time (enough time to discharge the pellet-shaped insulating material 2 containing metallic foreign matter to the outside). After a period of time has elapsed, the switching valve 10 is closed (the inlet of the discharge path 9 is closed).

By opening and closing the switching valve 10 in this way, the pellet-shaped insulating material 2 containing metallic foreign matter is supplied to the hopper (not shown) of the extrusion molding machine via the conveyance path 3. to prevent

Note that 12 is an amplifier that amplifies the 8-power signals from the plurality of detectors 8 and outputs 8-power signals to the valve opening/closing control device 11 .

Next, the operation will be explained.

First, the high frequency irradiator 5 is activated, and a high frequency of several thousand MHz (600 MI (around z)) is transmitted from the high frequency irradiator 5 to the carrier path 3.
Irradiate inside. Then, the pellet-shaped insulating material 2 is quantitatively delivered at a predetermined speed from the transport device 4 into the transport path 3 where the high-frequency waves are irradiated.

This pellet-shaped insulating material 2 is delivered by blowing.

When the pellet-like insulating material 2 air-fed by the conveying device 4 approaches the high-frequency irradiation chamber 7 and metallic foreign matter is mixed into the pellet-like insulating material 2, the electric field concentrates on the metallic foreign matter, and the high-frequency Electric discharge occurs, producing light and sound at the metallic foreign object. Light or sound generated by this high frequency discharge is detected by a detector 8.

When the detector 8 detects that metallic foreign matter is mixed into the pellet-shaped insulating material 2, this detection signal is sent to the valve opening/closing control device 11, which controls the switching valve 10. The opening/closing operation is controlled, and the pellet-shaped insulating material 2
After a period of time that takes into consideration the moving speed of and the distance to the switching valve 10, the switching valve 10 is opened (the entrance of the discharge path 9 is opened), the entrance of the discharge path 9 is opened, and the conveyance path 32 is closed. . Then, the pellet-shaped insulating material 2 containing the metallic foreign matter is discharged to the outside and removed from the conveyance path 3. After that, for an appropriate amount of time (
After a period sufficient to discharge the pellet-shaped insulating material 2 containing metallic foreign matter to the outside, the switching valve 10 is closed (the discharge path 9
(close the entrance).

By opening and closing the switching valve l○ in this way, the pellet-shaped insulating material 2 containing metallic foreign matter is transferred to the hopper (not shown) of the extrusion molding machine via the conveyance path 3.
Prevent it from being supplied to

Effects of the Invention 1 Since the present invention is configured as described above, it produces effects as described below.

In the process of conveying pellet-shaped insulating material for electric wires and cables, which is melted and extruded from a synthetic resin material and coated on running wires, through a transfer line, the pellet-shaped insulating material being conveyed in the transfer line is irradiated with high frequency waves to form pellets. The metallic foreign matter is detected by the light or sound generated when the metallic foreign matter mixed in the insulating material passes through, and the pellet-like insulating material before and after the pellet-like insulating material where the metallic foreign matter is detected is detected. Since the method is designed to remove metal foreign substances during transportation, if the pellet-shaped insulating material contains metal foreign substances, the wire/cable production line can be removed without stopping the pellet-shaped insulating material. The supply of insulating material can be stopped.

In addition, a high-frequency irradiator is installed on the conveyance path that conveys the pellet-shaped insulating material, which is melt-extruded and coated with a synthetic resin material to form the insulation of electric wires and cables, and is equipped with a high-frequency irradiator that irradiates high-frequency waves to the pellet-shaped insulating material that moves within the conveyance path. and a detector for detecting light or sound accompanying high-frequency discharge generated in metallic foreign matter mixed into the pellet-shaped insulating material due to high-frequency irradiation by the high-frequency irradiator, and a position where the high-frequency irradiator is installed on the conveyance path. A discharge path for discharging the pellet-like insulating material is provided at an appropriate location on the downstream side in the conveyance direction, and a switching valve is provided at the entrance of the discharge path to receive a detection signal from the detector and switch between the conveyance path and the discharge path. , a valve opening/closing control device is provided that controls the opening and closing of the switching valve based on the detection of light or sound by the detector, and the switching valve is actuated when light or sound is detected by the detector to prevent the contamination of metallic foreign matter. Since the pellet-shaped insulating material is carried out to the outside through the discharge path, if the pellet-shaped #@ edge material contains metallic foreign matter, it can be removed without stopping the electric wire/cable production line. It is possible to stop supplying the pellet-shaped insulating material to the area where the foreign matter is contained.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the first invention of the present invention and the second invention of the present application.

Claims (2)

[Claims] (1) In the process of transporting pellet-shaped insulating material for electric wires and cables, which is melted and extruded from synthetic resin material and coated on running wires, in a transfer line, the pellet-shaped insulating material being transported in the transfer line is irradiated with high frequency waves. The metallic foreign matter is detected by the light or sound generated when the metallic foreign matter mixed in the pellet-shaped insulating material passes through, and the pellet-shaped insulating material before and after the pellet-shaped insulating material where the metallic foreign matter is detected is pelletized. A method for removing metallic foreign matter mixed into a pellet-like insulating material, characterized in that the metallic foreign matter mixed into the pellet-like insulating material is prevented from being transported by removing the metallic foreign matter mixed into the pellet-like insulating material during transportation of the insulating material. (2) High-frequency irradiation that irradiates high-frequency waves to the conveyance path that conveys the pellet-like insulating material that is melt-extruded and coated with synthetic resin material to form the insulation of electric wires and cables, and the pellet-like insulating material that moves within the conveyance path. and a detector for detecting light or sound accompanying high-frequency discharge generated in metallic foreign matter mixed into the pellet-shaped insulating material by high-frequency irradiation by the high-frequency irradiator, and the high-frequency irradiator is provided on the conveyance path. A discharge path for discharging the above-mentioned pellet-like insulating material is provided at an appropriate location on the downstream side in the conveyance direction from the installation position, and a switching valve is provided at the entrance of this discharge passage to receive a detection signal from the detector and switch between the conveyance path and the discharge path. and a valve opening/closing control device for driving and controlling the switching valve based on the detection of light or sound by the detector, and driving the switching valve when light or sound is detected by the detector to detect metallic foreign objects. 1. A device for removing metallic foreign matter mixed into pellet-like insulating material, characterized in that the pellet-like insulating material mixed with is carried out from the discharge path to the outside.