Method for controlling capacitive reactance value

FIELD: controlling electric cable sheath capacitive reactance.

SUBSTANCE: proposed method for controlling capacitive reactance of tubular sheath formed by means of extrusion of insulating compound on electric cable in extrusion head includes introduction of foaming agent in insulating compound so as to enhance capacitive reactance of tubular insulating sheath; prior to do so, definite amount of foaming agent is used so as to obtain predetermined capacitive reactance for tubular insulating sheath and in order to ensure precision control of capacitive reactance of tubular insulating sheath, gas pressure is applied to at least external surface area of insulating compound extruded by extrusion head, gas pressure being varied so as to control capacitive reactance value of tubular insulating sheath.

EFFECT: enhanced precision of controlling capacitive reactance of electric-cable sheath.

9 cl, 3 dwg

 

This invention relates to a method of controlling the magnitude of the capacitance of the electric shell made in the electric cable by extrusion and deposition of electrical insulating compound for electrical cable.

This invention also relates:

- to the extrusion line, which operates according to the method

- an electrical cable containing a tubular shell formed by the extrusion of the insulating compound on this electric cable, and the value of the capacitance of which is controlled according to the method.

The invention relates more specifically, but not exclusively, to a method of controlling the magnitude of the capacitance of the sheath of foamed insulating compound, extruded metal wire.

The invention preferably, but not exclusively, applied to the method of controlling the capacitive resistance of the envelope of foamed material, which ekstragiruyut on the metal wire.

The main objective of the invention is to precisely control the magnitude of the capacitance of the electric shell made in the electric cable.

This object is achieved in that the method of controlling the magnitude of the capacitance of the tubular oblock is, made by extrusion of electrical insulating compound for electrical cable in the extrusion head, in which the insulating compound is injected foaming agent thus to increase the value of the capacitance of the tubular insulating sheath, with

- a pre-defined amount of foaming agent used in such a way as to obtain the predetermined value of capacitance for tubular insulating shell, and

for precise control of the magnitude of the capacitance of the tubular insulating sheath is applied gas pressure at least at the area of the outer surface of the insulating compound, extrudable extrusion head,

- the amount of gas pressure change in such a way as to control the magnitude of the capacitance of the tubular insulating shell.

The invention also relates to the extrusion line, which operates according to the method.

The invention also relates to an electrical cable containing a tubular shell made by extrusion of electrical insulating compound for this electric cable, and the value of the capacitance of which is controlled according to the method.

The invention may be better understood from Nigella the existing descriptions, this means a non-limiting example, with reference to the accompanying drawings.

1 shows an extrusion line, which can operate according to the method according to the invention.

Figure 2 shows a partial longitudinal section of an extrusion head of the extrusion line in figure 1.

Figure 3 shows a partial perspective view of the extrusion head 2.

Figure 1 shows an extrusion line that used to run on electric line 3 of the casing 1 of insulating compound 2.

This extrusion line contains at least the main extruder 18, including extrusion head 4, and an extrusion head provides accommodation for foam insulation at least around the cable 3.

Preferably, but not exclusively, this extrusion line contains:

wire-drawing mechanism 14, which provides a reduction of the cable diameter 3 (diameter copper cable parts) between the inlet and outlet mechanism,

mechanism 15 annealing, which provides the weakening of the cable 3,

mechanism 16 heater that provides heating cable 3, to improve the adhesion of the insulating compound 2,

- the main extruder 18 containing the extrusion head 4,

- movable chute 20 for the OHL is proving water, which is used to stop the expansion of the foam,

the tank 21 for hot water, which is a tank of water to a rolling gutters,

- thrust washer 22, which is pulling the puck line and by means of the capacitance measurement,

device 23, which is a means of measuring the diameter,

device 24, which is a means of measuring eccentricity,

device 25 spark test, which is a measure of insulation,

- tension device 26, where the cold insulated conductor at the end wound on the reel.

In this extrusion line instead of two mechanisms, which are wire-drawing mechanism 14 and the mechanism 15 annealing, it is possible to use a so-called unwinding device. In such extrusion line between the tank 21 for hot water and traction washer 22 can be placed cold stationary chute.

With reference to figure 2 and 3 it should be noted that the tubular shell 1 is formed by extrusion of the insulating compound 2 on the electrical cable 3 in the extrusion head 4, and a foaming agent 200 is introduced into the insulating compound 2 thus, to improve the value of C1 the capacitance of the tubular insulating shell 1.

The value of eating ostogo resistance tubular shell 1 depends on the magnitude of the dielectric constant insulating compound 2. The value of dielectric permeability changes when insulating compound foamed using a foaming agent 200, which is injected into the insulating resin before extrusion (chemical or physical foaming foaming). For example, the foaming agent 200 is a gas, namely nitrogen. Preferably, but not exclusively, extrusion line contains a section of the discharge of high pressure nitrogen, which combined with the main extruder 18.

You can also use the optional auxiliary extruder 17 to place the first outer layer of insulation around the cable 3 to enhance adhesion of the physical foaming (do not use with chemical foaming, and it is optional, but recommended physical foaming).

You can also use other optional auxiliary extruder 18 to provide accommodation around the insulating compound of the second outer insulation layer (for example, painted the outer layer).

In accordance with the method according to the invention:

- a pre-defined amount of foaming agent 200 is used so that for a tubular insulating shell 1 to obtain the predetermined value C1 of the capacitive resistance, and

for precise control of the values of the th C1 the capacitance of the tubular insulating shell 1 put pressure 110 gas at least in the area of the outer surface 100, 101 electrical insulating compound 2, extrudable extrusion head 4, a pressure of 110 gas changes thus to control the value of C1 the capacitance of the tubular insulating shell 1.

In one embodiment, taking the atmospheric pressure as the reference level, pressure 110 of the gas applied at least on the area of the outer surface 100, 101 of the insulating compound 2, extrudable extrusion head 4, is negative.

In the embodiment, taking the atmospheric pressure as the reference level, pressure 110 of the gas applied at least on the area of the outer surface 100, 101 of the insulating compound 2, extrudable extrusion head 4, is positive.

With reference to figure 2 and 3 it should be noted that the tubular shell 1 is formed by extrusion of the insulating compound 2 on the electrical cable 3 in the extrusion head 4, with the tip 5 from the front surface 6, in which there are:

hole 7, called axial hole 7 is formed so as to allow passage of the electrical cable 3 to be made in the shell, and

- ring-shaped opening 8 with a center coincident with the center axis of the hole 7, and is annular about the opening 8 is designed for flow 9 electrical insulating compound 2, the material which takes the form of a conical wall 10, covering the electrical cable at a predefined distance from the front surface 6 of the lug 5 so as to form a tubular shell 1 around the cable, thus component tubular insulating shell 1, with the measured value C1 of the capacitive resistance.

The main extruder 18, which contains the extrusion head 4 also contains a device 13 for measuring the magnitude of the capacitance C1 of the tubular insulating shell 1 made around the electrical cable 3.

It should also be noted that

- for the application of negative pressure 110 gas at least in the area of the outer surface 100, 101 of the insulating compound 2, extrudable extrusion head 4, generate a vacuum in a tapering volume 12, contained within the conical wall 10, and

- the magnitude of the vacuum generated in tapering volume 12 within the conical wall 10, change in such a way as to control the value of C1 the capacitance of the tubular insulating shell 1.

In addition, it should be noted that:

the suction device 11 is connected with a tip 5 and operates to create a vacuum in tapering volume 12, contained within the conical wall 10, and

- deliciousity, created by the suction device 11 in a tapering volume 12 within the conical wall 10 formed through the ring-shaped opening 8, insulating compound 2, change in such a way as to control the amount of capacitance C1 of the tubular insulating shell 1. Specialist in the art can find the most suitable suction device 11 to obtain the desired dilution.

These technical features allow you to control the magnitude of the capacitance of the electric shell provided on an electric cable, without changing the composition of the compound.

The method has the following steps:

before the extrusion of the insulating compound 2 on the electrical cable 3 connect the suction device 11 adjustable type with tip 5, that is, the suction device, which can be controlled to provide the desired amount of vacuum, and

during the extrusion of the insulating compound 2 on the electrical cable 3 perform the following additional steps:

• set preset value C2 of the capacitive resistance of the tubular insulating shell 1,

• set top C2S and lower C2I maximum permissible values for a given value of C2,

• measured capacitance C1 tubular obolos and 1, made around the cable 3, and compares it with the target value C2, and

• upon detection of a predetermined deviation from the setpoint C2 change the magnitude of the vacuum generated in tapering volume 12 within the conical wall 10 formed through the ring-shaped opening 8, insulating compound 2, thus, to adjust the value of the capacitance C1 of the tubular shell 1 made around the cable 3.

With reference to the drawings it may be noted that the tubular shell 1 is formed by extrusion of the insulating compound 2 on the electrical cable 3 with a diameter D1, which is called the first diameter.

Tip 5 has a front surface 6, in which there are:

hole 7, which is the axial hole 7 having such a shape to allow passage of the electrical cable 3 to be made in the shell, and

- ring-shaped opening 8 with a center coincident with the center of the axial bore 7, and this ring-shaped opening 8 is defined by an inner diameter D2, which second diameter greater than the first diameter D1 of the electrical cable 3, and the outer diameter D3, which is the third diameter greater than the second diameter D2, the opening 8 is designed for flow 9 electrical insulation to the of mpound 2.

This insulating compound 2 takes the form of a conical wall 10, which covers the electrical cable at a predefined distance from the front surface 6 of the lug 5 in such a way as to form a tubular shell 1 around the cable of the fourth diameter D4, thus providing a tubular insulating shell 1, with the measured value C1 of the capacitive resistance.

According to the method according to the invention, the first diameter D1 is set at the predetermined value by controlling the speed of the electrical cable 3 and the tubular shell 1 formed by extrusion of electrical insulating compound for electrical cable 3.

As can be seen in the drawings, electrical insulating compound 2 emerges from the annular orifice 8 with a predetermined linear velocity, depending on the speed of rotation of the screw extrusion, which is used in the extrusion head 4.

For example, the first diameter D1 is set at the predetermined value by controlling the speed of rotation of the screw extrusion in the extruder 18 containing the extrusion head 4, from which comes insulating compound 2.

The capacity and diameter are related to each other, but modification of the vacuum will affect the diameter, however, this influence is very limited what about and almost irrelevant to the process.

1. The method of controlling the capacitive resistance of the tubular shell formed by extrusion of electrical insulating compound for electrical cable in the extrusion head, in which the insulating compound is injected foaming agent in such a way as to increase the capacitance of the tubular insulating sheath, characterized in that a predetermined quantity of foaming agent is used in such a way as to obtain a predetermined capacitance to the tubular insulating sheath, and to precisely control the capacitive resistance of the tubular insulating sheath apply gas pressure to at least the area of the outer surface of the insulating compound, extrudable extrusion head, the amount of gas pressure change thus to operate capacitive resistance of the tubular insulating shell.

2. The method according to claim 1, characterized in that when the atmospheric pressure as the reference level, the gas pressure applied to at least the area of the outer surface of the insulating compound, extrudable extrusion head, is negative.

3. The method according to claim 1, characterized in that when the atmospheric pressure as the reference level, the pressure of the Aza, apply at least the area of the outer surface of the insulating compound, extrudable extrusion head, is positive.

4. The method of controlling the capacitive resistance of the tubular shell formed by extrusion of electrical insulating compound for electrical cable extrusion head having a tip, comprising a front surface, which face the hole, which is the axial hole formed to allow passage of the electrical cable to be made in the shell, and the annular aperture with a center coincident with the center of the axial bore, and this annular opening is used for the flow of electrical insulating compound material which takes the form of a conical wall covering electrical cable at a predefined distance from the front surface of the handpiece in such a way as to form a tubular sheath around the cable thus component tubular insulating shell having a measured value capacitance, characterized in that for the application of negative pressure gas at least in the area of the outer surface of the insulating compound, extrudable extrusion head is th, generate a vacuum in tapering the volume contained within the conical wall, and the magnitude of the vacuum generated in tapering the volume of the inside of the conical wall, change thereby to control the magnitude of the capacitance of the tubular insulating shell.

5. The method according to claim 4, characterized in that the suction device is connected to the tip and is used to create a vacuum in tapering the volume contained within the conical wall, and the magnitude of the vacuum generated by the suction device in tapering the volume inside tapered wall formed through the annular hole of the insulating compound, modify, thus, to control the magnitude of the capacitance of the tubular insulating shell.

6. The method according to claim 5, characterized in that before the extrusion of the insulating compound on the electrical cable to the handpiece is connected to the suction device of the controlled type and during extrusion of electrical insulating compound for electrical cable perform the following steps: establish a given value of capacitance for tubular insulating shell, set the upper and lower limit values for a given value of capacitance, the measured capacitance of trubo is the shell, formed around the cable, and compare it with the preset value of the capacitance, and upon detection of a predetermined deviation from a specified value capacitance change of the magnitude of the vacuum generated in tapering the volume inside tapered wall formed through the ring-shaped opening, insulating compound thus to change the size of the capacitance of the tubular shell made around the cable.

7. The method according to one of claims 1 to 6, characterized in that the first diameter of the electrical cable is set at the predetermined value by controlling the speed of the electrical cable and the tubular shell formed by extrusion of electrical insulating compound for this electrical cable.

8. Extrusion line, characterized in that it operates according to the method according to one of claims 1 to 7.

9. Electrical cable containing a tubular shell formed by the extrusion of the insulating compound on this electric cable, while the value of the capacitance is controlled according to the method according to one of claims 1 to 7.



 

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