JPS6016687B2 - Extruded insulated cable continuous cooling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an extruded insulated cable continuous cooling device that continuously cools an extruded insulated cable during its manufacturing process.

For example, when manufacturing a cross-linked polyethylene cable, the polyethylene insulated cable obtained in the extrusion process using an extruder is immediately passed through the cross-linking process using a cross-linking device without being cooled, and heat cross-linking is performed. It is cooled down to about room temperature.

However, conventionally, a cooling device uses cooling water and uses the sensible heat of the water for cooling, which has the disadvantage of poor cooling efficiency and, in this connection, the disadvantage that the cooling process becomes long.

In order to improve this problem, an extruded insulated cable continuous cooling device has been proposed that shortens the cooling process by cooling the extruded insulated cable using a boiling cooling medium as the cooling medium.

However, when extruded insulated cables are cooled with a boiling cooling medium, the outside of the rubber or plastic insulating layer is rapidly cooled after being crosslinked by heating, resulting in a hard shell forming on the surface, and then the inside slowly cools down. It will be cooled down.

For this reason, voids are likely to occur inside the hard outer shell.
As a result, the density of the inner layer decreases, resulting in a disadvantage that the withstand voltage performance decreases. Moreover, such rapid cooling leaves thermal distortion in the rubber or plastic insulating layer, and this effect becomes apparent during use, which is undesirable. Furthermore, if a hard shell is formed on the surface during quenching, cracks may occur on the surface, which is undesirable. In addition, in conventional cooling devices, there is a pressure difference of more than one hydrophobic pressure between the outside and the outside of the sealed part of the boiling cooling part, so there is a drawback that the liquid phase cooling medium is ejected at high pressure from this sealed part. there were. For this reason, the subordinate installed a receiving tank under the seal to collect the liquid, but due to the high pressure, the liquid would scatter, making it difficult to collect and worsening the working environment. The purpose of the present invention is to
An object of the present invention is to provide a continuous cooling device for extruded insulated cables that can prevent harmful effects caused by rapid cooling even when a boiling cooling medium is used, and can suppress jetting of a liquid phase cooling medium at a seal portion.

In the present invention, a vapor-liquid two-phase cooling medium for boiling cooling is used as a cooling medium housed in a cooling container, and a moving extruded insulated cable is first guided into the gas phase of this cooling medium and slowly cooled, and then the liquid is cooled. By guiding the liquid into the phase and boiling it to cool it, and by making the moving extruded insulated cable penetrate through the multi-stage seals of the cooling container, and collecting the liquid at each stage's seals,
The pressure difference is gradually reduced to lower the liquid ejection pressure and at the same time, the liquid is recovered.

As the gas-liquid two-phase cooling medium for boiling cooling, for example, fluorocarbon, fluorine oil, trifluoroethyl alcohol, or the like is used. Among these, for example, Freon R-11 (CC13F),
R-112 (CC12F/CC12F), R-113 (
The equilibrium vapor pressure of CC12F, CCIF2), etc. is as shown in Figure 1, and is uniquely determined by temperature and pressure.

Therefore, when the cable, which is an object to be cooled, enters the fluorocarbon container, if its temperature is higher than the equilibrium temperature, the fluorocarbon boils, absorbs latent heat of vaporization from the cable, and vaporizes. Therefore,
The cable will be efficiently cooled by using the latent heat of Freon. In this case, the cable first passes through the vaporized chlorofluorocarbon and is slowly cooled, and then is boiled and cooled.

Examples of fluorine oil include C8F,60, C8F,6,
C7F, 4, C Yoha, C, oF, 8, C, 2F27N
etc. can be used.

The physical properties of C8F,60 (perfluorocyclic ether mixture) in such fluorine oil are as follows. Physical properties boiling point of C8F,60 102. ○ Pour point 193℃ Vapor pressure 25C0 3 specific gravity Hgabs
1.76 viscosity at 260
0.8 centitokes latent heat of vaporization at 2de0 2
1Kcal/g Specific heat 0.2&al/g℃ Dielectric strength voltage 21.7KV at 260/spring n6
,, dielectric constant of 3×10-4 or more at 25oo
1.87 Next, trifluoroethyl alcohol has a boiling point of 75°C, and it may be used alone or in a mixture with water.

For example, 85% by weight of trifluoroethyl alcohol and 1 part of water.
A mixture of 5% by weight is used. FIG. 2 shows an example of an insulated cable manufacturing apparatus including an extruded insulated cable continuous cooling device according to the present invention.

As shown in the figure, the cable core 1 passes through the turn sheep 2 and enters the crosshead 3 of the extruder, and the outer periphery is coated with extruded rubber and plastic insulation material containing a crosslinking agent.
This becomes an extruded insulated cable 4. The insulated cable 4 immediately enters the bridging tube 6 of the bridging device 5 and is heated.

Crosslinking is carried out using, for example, an inert gas, infrared rays, ultrasonic waves, or the like. The crosslinked extruded insulated cable 4 is then subjected to an insulated cable continuous cooling device 7 according to the present invention.
and cooled to room temperature.

This cooling device 7 includes a gas-liquid two-phase evaporative cooling section 9 that gradually cools the extruded insulated cable 4 in the gas phase of a vapor-liquid two-phase cooling medium 8 for evaporative cooling, and then evaporates and cools it in the liquid phase. It includes a sealing part 10 for sealing in multiple stages to prevent the vapor-liquid two-phase cooling medium 8 for boiling cooling from leaking to the outside from the cable penetration part of the vapor-liquid two-phase boiling cooling part 9, and for collecting leaked liquid. It is organized. The gas-liquid two-phase boiling cooling unit 9 includes a vertically long cylindrical cooling container 1 that is installed continuously on the bridge tube 6.
1, and this cooling container 11 is filled with Freon 8 as a vapor-liquid two-phase cooling medium 8 for boiling cooling.

The cross-linked high temperature extruded insulated cable 4 is placed in the cooling container 11
When the Freon 8 enters the interior and comes into contact with the liquid of Freon 8 (for example, R-113), the Freon 8 boils and the extruded insulated cable 4 is vaporized by the latent heat of vaporization, becoming a gas phase. Therefore, the inside of the cooling container 11 is filled with a gas-liquid two-phase cooling medium 8 in which the fluorocarbon 8 exists in a liquid phase in the lower part and the fluorocarbon 8 exists in a vapor phase in the upper part. The extruded insulated cable 4 is efficiently cooled by the latent heat of vaporization of the freon 8. At this time, an appropriate section is set for the gas phase of the Freon 8, and the extruded insulated cable 4 is gradually covered by the gaseous Freon 8 before reaching the liquid phase of the Freon 8, so that the extruded insulated cable 4 is rapidly cooled. You can prevent this from happening. This is an order of magnitude higher when comparing the heat transfer between the gas phase Freon 8 and the cable 4, the heat transfer between the liquid phase Freon 8 and the cable 4, and the heat transfer between the liquid phase Freon 8 and the cable 4. This is because the latter has a greater heat transfer effect.
In gas phase cooling, as the intensity of liquid evaporation increases, the flow velocity of the gas phase increases and the slow cooling effect increases, so if slow cooling is insufficient, it works to improve this. There are benefits. A bypass passage 13 is provided in the cooling container 11 of the gas-liquid two-phase boiling cooling unit 9, and a condenser 14 is provided in the bypass passage 13, and the freon 8 in the gas phase is transferred to the condenser 14.
The liquid is then reliquefied and returned to the cooling container 11.

The condenser 14 uses a cooling medium such as water to exchange heat with the fluorocarbon gas. The pressure inside the cooling container 11 is uniquely determined by the refrigerant temperature, which is determined by the amount of heat exchanged by the condenser 14 and the temperature of the cable 4, from an equilibrium vapor pressure curve as shown in FIG.

In addition, the temperature inside the cooling container 11 may be in a gas phase or a liquid phase),
are at the same temperature. A seal portion 10G provided on the bottom side of the cooling container 11, and rubber elastic sealing materials 15, 152, 153, 15 provided in multiple stages inside the cooling container 11.
4..., and the cable 4 sequentially passes through these sealing materials 15, 152... to exit to the outside.

Each sealing material 15, 152... is a partition plate 16, 162, 163, 16 extending from the inner surface of the cooling container 11.
4... are installed respectively. In addition, each sealing material 1
5, 152, . . . are biased by biasing bodies 17, 172, 173, 174, etc. such as springs so as to be brought into close contact with the cable 4. By collecting the leaked liquid on the sealing material of each stage, the pressure difference between the inside and outside of the sealing member of each stage gradually decreases, and the jetting pressure of the liquid can be weakened. In order to collect the liquid phase Freon 8 that leaked from the upper sealing material 15 and accumulated on the lower sealing material, a cooling container is placed above the lower sealing material 152, 153 and above it. A recovery pipe 18 is provided to connect the inside of the sealing material 152,1.
The freon 8 accumulated on the top of the cooling container 53 is sucked up by a pump 19 and returned into the cooling container 11. Therefore, the expensive vapor-liquid two-phase cooling medium 8 for boiling cooling can be prevented from being spouted out to the outside under high pressure and can be reused. A check valve 20 is provided at a portion where the downstream recovery pipe 18 is connected to the upstream recovery pipe 18 to prevent the cooling medium from flowing from the upstream recovery pipe 18 to the downstream recovery pipe 18. In the above embodiments, the case where cooling is performed after crosslinking has been described, but the present invention is not limited to this. For example, in the case where crosslinking is not performed, extruded insulated cables that are cooled immediately after extrusion can also be manufactured. Of course, it can be applied.

As explained above, the extruded insulated cable continuous cooling device according to the present invention uses a vapor-liquid two-phase cooling medium for boiling cooling as the cooling medium housed in the cooler, and first guides the cable into the gas phase of this cooling medium. Since the cable is cooled slowly, the rubber and plastic insulation layers of the cable can be prevented from being cooled too quickly.

Therefore, only the outer side of the rubber or plastic insulating layer is not hardened into a shell shape first, thereby preventing the generation of voids and reducing the withstand voltage performance. Further, it is possible to prevent thermal strain from remaining in the comb and plastic insulating layer, and also to prevent cracks from forming on the surface. Furthermore, if a gas-liquid two-phase cooling medium is used and slow cooling is performed in the gas phase, there is no need to use a separate cooling medium for slow cooling, which simplifies the configuration of the apparatus. Furthermore, as the temperature of the cable increases and the strength of liquid evaporation increases, the flow velocity of the gas phase increases and the gradual cooling effect increases, so the gradual cooling effect can be automatically varied according to the boiling cooling effect. There are advantages. Next, in the present invention, the seal part of the cooler has a multi-stage configuration, and the leaked liquid is stored in each stage, so the pressure difference between the inside and outside of each seal stage gradually decreases, causing the liquid to gush out. It is possible to weaken the pressure and prevent the liquid from escaping.Also, since the liquid is collected in the seal stage, the liquid is collected in a closed space, eliminating the possibility of spouting into the air. It is possible to perform the work well and to prevent deterioration of the working environment.

[Brief explanation of drawings]

FIG. 1 is a temperature-pressure characteristic diagram of fluorocarbon as a cooling medium, and FIG. 2 is a schematic sectional view of an extruded insulated cable manufacturing apparatus using the cooling device of the present invention. 7... continuous cooling device, 8... cooling medium for boiling cooling,
9... Boiling cooling section, 10...Sealing section, ]1... Cooling device, 1
5, to 154...Sealing material, 16. ~164...Partition plate, 1
8...Recovery pipe, 19...Pump, 20...Check valve. Figure 1 Figure 2

Claims (1)

[Claims] 1. In an extruded insulated cable continuous cooling device that continuously cools a manufactured extruded insulated cable by passing it through the extruded insulated cable continuously, the cooling container contains a gas-liquid two-phase cooling medium for boiling cooling. After slowly cooling the cable by passing it through the gas phase,
A gas-liquid two-phase evaporative cooling unit that evaporates and cools the cooling medium by passing through the liquid phase, and a cable penetration portion in a cooling container of the gas-liquid two-phase evaporative cooling unit to seal the cooling medium from leaking to the outside. a sealing part, the sealing part is arranged in multiple stages along the passing direction of the cable, and includes a sealing material for sealing the penetrating part of the cable, and a sealing material for sealing the penetration part of the cable, and a sealing material for sealing from the previous stage sealing material to the rear stage sealing material. A continuous cooling device for extruded insulated cables, comprising a pipe and a recovery pump for collecting the leaked cooling medium into the cooling container. 2. The extruded insulated cable according to claim 1, wherein the seal portion is provided with a check valve connected to a portion that communicates and connects a recovery pipe at a later stage to a recovery pipe at a front stage. Continuous cooling device.