JPS60100310A - Method of controlling coolant level of cable continuous crosslinking device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for controlling the level of cooling water in a continuous cable crosslinking device to a constant level.

(Prior art) In a continuous cross-linking device for rubber or plastic insulated cables, a cable extruded and covered with rubber, plastic, etc. using an extruder is run through a heating section of a cross-linked pipe to heat cross-link.
The cooling water is then run through the cooling section, cooled, and drawn out of the bridge pipe through the end seal at the end of the cooling section.A certain amount of cooling water leaks from this end seal, so the amount of leaked water can be reduced. In order to compensate for this and keep the cooling water at a low humidity, cooling water was constantly replenished during continuous crosslinking operation to maintain the cooling water level in the cooling section at a predetermined level. For this reason, conventionally, as shown in the first diagram, cooling water from a water tank 5 was supplied and circulated to the cooling section 3 of the bridge pipe 1 using a high-pressure pump 4. Regarding replenishment of the amount of cooling water leaking from the end seal 6 when the cable C running between the heating section 2 in the bridge pipe 1 and the following cold buoy 1 section 3 exits the pipe from the end seal 6 at the end of the cooling section. , the detected pressures of the pressure detection sensor α of the heating VAX 2 and the pressure detection sensor b of the cooling unit 3 are input to the differential pressure oscillator 7, and the difference between the rain detection pressures based on the fluctuation of the cooling water level is detected by the output of the oscillator. Opening adjustment part 8
The amount of water to be supplied to the cooling unit 3 was adjusted using an electro-pneumatic converter that converts electricity from air pressure to adjust the opening degree of the Guyafram valve 9 by driving.

However, when a cable starts running in a cross-linked pipe, a lead wire is connected to the cable end at the running end and the cable is pulled to run, so the diameter of the cable end and the diameter of the lead wire are different. If the difference is large, a sudden change in the amount of leaking water occurs when the cable tip passes through the end seal 6, making it impossible to avoid a sudden drop in the cooling water level in the cooling section. On the other hand, conventional electro-pneumatic converters have slow response speeds and cannot immediately follow sudden changes in water level, resulting in water level hunting, and when the continuous cross-linking equipment starts operating, Even when the pressure is increased, there is a drawback that hunting occurs in the water level due to the delayed response of the diaphragm valve 9.

As for the above-mentioned fluctuations in cooling water, if the slope of the cross-linked pipe is gentle, even a slight change in the water level will cause a large change in the cooling length and a large change in water volume, so the slope of the cross-linked pipe cannot be made gentler than a certain level. However, it would be necessary to raise the building where the bridge pipes were installed by that slope, or to install the cooling pipes on the back of the underground bit, making it impossible to avoid a rise in construction costs.

In addition, the Mv medium and oil agent filled in the heating part of the crosslinked pipe,
When using molten metal salt, etc., it is necessary to separate the heating section and the cooling section to prevent direct contact between the 1l-1l heat medium and cooling water, but due to some reason, the crosslinking pressure may fluctuate or the cooling water level may change. If a control beam were to malfunction, the heat medium and cooling water would instantly mix together, potentially causing a huge disaster such as a steam explosion and damaging the equipment.

Even when the above-mentioned heating is carried out by radiation heating, if cooling water enters the heated part, there is a risk that the pipe wall will be distorted due to rapid cooling, causing cracks and damage, or a steam explosion. Even if the amount of noise generated is small, there is a risk that the electrical characteristics of the cable insulated wave device will be deteriorated.

In this way, it is extremely important to control and maintain the cooling water level at a predetermined level to prevent sudden fluctuations or runaway changes in the water level, but it is possible to immediately prevent sudden fluctuations in the water level. Such a method had not been realized before.

(Object of the Invention) In view of the above-mentioned points, the present invention prevents rapid fluctuations in the cooling water level even if any situation occurs such as fluctuations in the internal pressure of the bridge pipe or disturbances.
The present invention provides a cooling water level control method for a continuous cable bridging device that allows cooling water in a cooling section to be always maintained at a predetermined water level.

(Horizontal G of invention) Hereinafter, the 6176 will be explained with reference to the embodiments shown in FIGS. 2 to 5. FIG. 2 shows one embodiment of the present invention, FIG. 3 shows a portion of its overflow, and FIGS. 4 and 5 each show other embodiments.

In the embodiment shown in the second figure, 10 is a bridge pipe, and 11
The heating crosslinking section 12 is a cooling section. The cooling section 12 is provided with an end seal 13 at its end to fill with cold water W, and the heating bridging section 11 is filled with an inert gas or other heat medium 16 from a plumber 4 through a valve 15. Heating crosslinking section 1
1 is connected to an extrusion head 18 of an extruder 17. Extrusion via metering capstan 19 - throat 18 (
The cable C, which is covered with an extruded uncrosslinked insulator such as rubber or plastic, is connected to the above-mentioned crosslinked pipe 10.
The crosslinked pipe 10 is heated and crosslinked in the heating crosslinking section 1], is cooled by the cooling water W of the cooling section 12, passes through the end seal 13, and advances to the outside of the crosslinked pipe. Overflow part 2 in the middle part with part 12
Set 0. The A-bar flow part 20 consists of a receiving pipe part 21 connected to the middle part of the bridge pipe 10 and a downstream pipe part 22 extending downward from the bottom part. The water head of W allows the overflowed water to fall and flow into the receiving pipe section 21 and is received therein, and the downflow pipe section 22 allows the overflow water that has fallen and flowed into the receiving pipe section 21 to flow down into the water level stabilizing tank 23 below. It is something.

The water level stabilizing tank 23 is connected to the above-mentioned downflow pipe section 22, and also connected to a water supply pipe 26 leading to a high-pressure pump 24 and a water supply valve 25 to supply water into the tank and store cooling water. This tank contains water ffk flowing down from the downstream pipe section 22 and the water supply pipe 2.
The amount of water supplied from 6 is stored, and the amount of stored water is detected by the water level detection sensor 27, and the output of the level controller 28 drives the valve opening/closing drive unit 29 to control the opening/closing of the water supply valve 25. Adjustments are made.

In addition, a feed pipe 30 for feeding the cooling water stored in the tank to the cooling section is connected to the water level stabilizing tank 23, and this feed pipe 30 is connected to a low pressure line pump 31, a flow Hkft32
, are connected to the cooling section 12 of the bridge pipe via a valve 33. A bypass pipe 34 is branched in the middle of the feed pipe 30 and communicated with the water level stabilizing tank 23 via a bypass valve 35, and the amount of water diverted from the feed pipe 30 to the bypass pipe 34 is controlled by the opening degree of the bypass valve 35. The water base of the cooling water sent from the low-pressure line pump 31 to the cooling unit 12 is adjusted by adjusting.

Reference numeral 36 denotes a riser pipe that stands up from the pipe wall of the cooling section 12. The height of its upper end is adjusted to the permissible water head of the cooling water in the cooling section 12, and the water level is stabilized by the communicating pipe 38 via the valve 37. It communicates with the tank 23. As a result, even if a part of the overflow is clogged with foreign matter and the head of cooling water in the cooling section 12 reaches the allowable head, the riser pipe 36
Since the cooling water in the cooling unit 12 is sent to the water level stabilizing tank 23 through the communication pipe 38, safety is ensured.

39 is a pressure communication pipe, and since the inside of the bridge pipe is pressurized to a high level of 1-H, the pressure in the water level stabilizing tank 23 is communicated with the pressure in the bridge pipe to keep it at the same pressure.

The high-pressure pump 24 installed in the water supply pipe 26 may have a discharge pressure higher than the cross-linking pressure in the heated cross-linking section 11 of the cross-linked pipe, for example, approximately 5 kg/cnf or higher. Using a multi-stage turbine pump. In addition, the low pressure line pump 31 installed in the feed pipe 30 is
It is sufficient to have the ability to supply cooling water against the slight water supply resistance of the piping. That is, the same pressure P1 in the crosslinked pipe is always applied to the suction side and the discharge side of the pump 31, and if the water head loss due to the resistance of the pipe is set as △P, then
The pressure on the suction side of the pump 31 is Pl, and the required minimum pressure on the discharge side is P1+ΔP. Therefore, the minimum [
T:, the force is (p1 + ΔF) - El - ΔP, and since this ΔP is a constant value determined by the piping, the discharge pressure of the pump 31 is always constant even if the pressure inside the crosslinked pipe fluctuates. A slight pressure is sufficient.

In the embodiment shown in the second figure configured as described above, the uncrosslinked insulated cable C is run inside the bridge g10, the uncrosslinked insulation sheath is heated and crosslinked in the heating crosslinking section 1, and then the cooling water is applied in the cooling section 12. Therefore, the temperature of the cooling water W increases, but a certain amount of water leaks from the end seal 13 as the cable of the cooling section 12 runs, and the low-pressure line pump 31 removes more water than the leaked water. By constantly feeding the cooling water W to the cooling unit 12, the cooling water W in the cooling unit 12 is always maintained in a cold water state.

As described above, when the low-pressure line pump 31 supplies an amount of water greater than the amount of water leaking from the end seal 13 to the cooling section 12, the head of the cooling water W in the cooling section 12 tends to exceed a predetermined water head; The excess amount of water above the water head overflows into the receiving pipe section 21 of the overflow section 20 and flows into the water level stabilizing tank 23 from the downstream pipe section 22, so that the cooling water level is maintained at a predetermined water head. Naru 0
The amount of overflow water flowing into the part 20 of the A-bar 70 is always constant in a stable steady state where the amount of water leaking from the end seal 13 does not change and the amount of water supplied by the low line pump 31 does not change either. Yes, and
Even if there is a change in the leakage water lit from the end seal 13 or a change in the internal pressure of the bridge pipe, the amount of water falling into the overflow part 20 will only increase or decrease, and the cooling The predetermined water head of the cooling water in the section 12 is maintained constant without any fluctuation. therefore,
When the cable starts running inside the bridge pipe and the end of the cable with the lead wire connected passes through the end seal, water leaks 1.
, 1 (even if sudden changes in llj or the internal pressure of the bridge pipe occur, the water head of the cooling water in the cooling section 2 can always be kept constant M).

Due to the conclusion of the experiment, the low pressure line pump 31 that supplies cooling water W to the cooling section 12 was adjusted to a discharge pressure of 2'cg/cm'.
, discharge pressure 4OO~500. ．． ．． / minute capacity,
When the end seal 13 is closed, the overflow part 20 is caused to fall into the receiving pipe part 21, as shown in FIG.
The inflow width of the bar 70 - water WO was about 200 to 250 m1, and it was sufficient that the inner diameter of the receiving pipe section 21 was 300 mm or more.

FIG. 4 shows a heated cross-linked section 1 by curving the cross-linked pipe 1o downward.
This is an embodiment in which the present invention is applied to a continuous crosslinking device in which a heating crosslinking section 11 and a cooling section 12 are separated, using silicone oil, molten metal salt, etc. as the heating medium 16 filled in the heating medium 16. The same reference numerals as in Fig. 2 indicate the same parts.
In this embodiment as well, similarly to the embodiment shown in the second drawing, the overflow part 20 allows the overflow amount of the cooling water W to flow in to maintain the water level of the cooling water W in the cooling part 12 at a predetermined water level. .

Still, FIG. 5 shows that the above-mentioned overflow portions 20.20" are installed at two locations in the cooling section 12 of the bridge pipe.
,,The downstream pipe part 22 hanging down from the receiving pipe part 21 of one overflow part 20 is directly connected to the water level stabilizing tank 23 as in the previous embodiment, and the receiving pipe part 21 of the other part of the overflow part 20 is directly connected to the water level stabilizing tank 23. A practical example is shown in which the downstream part 22'' hanging down from the water level is connected to the water level stabilizing tank 23 via the fp40. In this FIG. 5 as well, the same reference numerals as in FIGS. 2 and 4 indicate the same parts. In this example, in the case of continuous crosslinking operation that requires the cooling water level to be maintained at head H,
The valve 40 provided in the downflow pipe portion 22' of the lower overflow portion 20' is kept closed.

As a result, the cooling water flowing into the lower overflow part 20' only fills the overflow part 20' up to the valve 40 and does not flow any further, so that the water fi in the cooling part 12 flows into the overflow part 20'. 20 to maintain the required water head H. Further, when continuous cross-linking is performed while maintaining the amount of cooling water at the lower water head H'', the above-mentioned valve 40 is opened and the upper valve 3 in the cooling water supply pipe 30 is opened.
Close 3 and 4-3<. As a result, the cooling water flows into the Meverflow part 20' and is sent to the water level stabilizing tank 23 through the valve 40. Since the cooling water is not sent above H", the water head of the cooling water at this time is is this overflow part 2
In this way, by installing parts of the over 70 in two locations in the cooling section 12, it is possible to vary the head of cooling water depending on the cable to be bridged. becomes.

In each of the above-described embodiments, the receiving pipe portions 21 and 21' of the overflow portion may have either a cylindrical shape or a prismatic shape, and the cooling portion 12 may be horizontal without being inclined. However, the water level can be controlled by the overflow part, and the level controller 2 shown in Figs.
A differential pressure oscillator can also be used instead of 8.

(Effects of the Invention) As described above, the present invention provides an overflow part in the cooling part of the cross-linked pipe, and communicates this with a water level stabilizing tank that has the same pressure as the pressure inside the cross-linked pipe, so that the cooling water in the cooling part is Since the amount of overflow water flows into the overflow part, even if there are fluctuations in the pressure inside the bridge pipe or the amount of cooling water leaking from the end seal, the cooling water in the cooling section will not be affected by the fluctuations. This makes it possible to always maintain the water level at a predetermined level, thereby preventing the occurrence of sudden changes in the cooling water level or runaway, such as steam explosions and damage to bridge pipes, which occur in the past. Since the length of the cooling section is stabilized at a constant length, it is possible to obtain a cable with uniform and good characteristics.

[Brief explanation of drawings]

FIG. 1 is a drawing showing a conventional example, FIG. 2 is a drawing showing an embodiment of the present invention, and FIG. 3 is a drawing showing a part of an oat floor.
FIG. 4 and FIG. 5 are drawings showing other embodiments, respectively. 10: Cross-linked pipe 12: Cooling section 20 Overflow part 23 2 Water level & tank Patent applicant Furukawa Electric Co., Ltd. Agent Patent attorney Oka 10 1' Ikudomari (and 1 other person) 15 Figure 3

Claims (1)

[Claims] Cooling water is fed to the cooling unit from a water level stabilizing tank whose internal pressure is the same as the internal pressure of the bridge pipe, and the overflow amount of the cooling water flows into an overflow part installed in the cooling unit and communicating with the water level stabilizing tank. 1. A cooling water level control method for a continuous cable bridging device, characterized in that the cooling water level in a cooling section is controlled to be constant.