阅读说明：本技术 柔性矿物绝缘金属护套电缆绝缘电阻不合格的修复方法 (Method for repairing unqualified insulation resistance of flexible mineral insulated metal sheathed cable ) 是由 夏峰 杨帆 丰如男 陈磊 刘凤伟 韩哲 于 2020-03-20 设计创作，主要内容包括：本发明公开了一种柔性矿物绝缘金属护套电缆绝缘电阻不合格的修复方法,特点是包括如下步骤：对电缆的绝缘电阻合格与否进行检测,得到绝缘电阻不合格的待修复电缆；在待修复电缆的一端用带气门的热缩封帽封好,另一端不封；通过气门向待修复电缆内部吹入氮气,对待修复电缆进行吹气处理；吹气4—6小时后,对完成吹气处理的电缆重新进行绝缘电阻合格与否的检测,若检测结果为不合格,重复步骤(3)和步骤(4)的操作；待绝缘电阻检测结果显示为合格,表示修复完成,在电缆两端密封安装上热缩封头,得到修复后可正常使用的电缆。优点是操作简单方便,有效减少报废,降低生产成本。(The invention discloses a method for repairing unqualified insulation resistance of a flexible mineral insulated metal sheathed cable, which is characterized by comprising the following steps: detecting whether the insulation resistance of the cable is qualified or not to obtain the cable to be repaired, wherein the insulation resistance of the cable is unqualified; one end of the cable to be repaired is sealed by a thermal shrinkage sealing cap with a valve, and the other end of the cable is not sealed; blowing nitrogen into the cable to be repaired through the air valve, and blowing the cable to be repaired; after blowing for 4-6 hours, detecting whether the insulation resistance of the cable subjected to the blowing treatment is qualified or not again, and repeating the operation of the step (3) and the step (4) if the detection result is unqualified; and when the insulation resistance detection result shows that the insulation resistance is qualified, indicating that the repair is finished, and sealing and installing heat-shrinkable end sockets at two ends of the cable to obtain the cable which can be normally used after the repair. The method has the advantages of simple and convenient operation, effective reduction of scrap and production cost reduction.)

1. The method for repairing the unqualified insulation resistance of the flexible mineral insulation metal sheath cable is characterized by comprising the following steps of:

(1) detecting whether the insulation resistance of the cable is qualified or not to obtain the cable to be repaired, wherein the insulation resistance of the cable is unqualified;

(2) one end of the cable to be repaired is sealed by a thermal shrinkage sealing cap with a valve, and the other end of the cable is not sealed;

(3) blowing nitrogen into the cable to be repaired through the air valve, and blowing the cable to be repaired;

(4) after blowing for 4-6 hours, detecting whether the insulation resistance of the cable subjected to the blowing treatment is qualified or not again, and repeating the operation of the step (3) and the step (4) if the detection result is unqualified;

(5) and when the insulation resistance detection result shows that the insulation resistance is qualified, indicating that the repair is finished, and sealing and installing heat-shrinkable end sockets at two ends of the cable to obtain the cable which can be normally used after the repair.

2. The method for repairing a failure in the insulation resistance of a flexible mineral insulated metal-sheathed cable according to claim 1, wherein the nitrogen gas to be blown in the step (3) is a high-purity nitrogen gas.

3. The method for repairing the defective insulation resistance of the flexible mineral insulated metal-sheathed cable according to claim 1 or 2, wherein in the step (3), a nitrogen gas cylinder filled with high-purity nitrogen gas is connected to the air valve, and the nitrogen gas is blown into the cable to be repaired by opening a switch on the nitrogen gas cylinder.

4. The method for repairing the unqualified insulation resistance of the flexible mineral insulated metal sheathed cable according to claim 3, wherein a heating device is arranged outside a nitrogen cylinder, the gas in the nitrogen cylinder is heated to 40-60 ℃ by the heating device, then the nitrogen cylinder is opened, the input pressure of the nitrogen is controlled to be 0.3-0.5 Mpa, and the cable to be repaired is subjected to blowing treatment.

Technical Field

The invention relates to the field of flexible mineral insulated metal sheathed cables, in particular to a method for repairing unqualified insulation resistance of a flexible mineral insulated metal sheathed cable.

Background

The flexible mineral insulated metal sheathed cable is an insulated cable which uses copper with high conductivity as a conductor, adopts inorganic mineral insulating tape to continuously wrap for insulation, and uses copper tape to longitudinally wrap and seamlessly weld for sheathing. The cable can continuously work at a high temperature of 250 ℃, has high fire characteristics (limit temperature 1083 ℃), is non-toxic when being burnt, and can be burnt for 3 hours under the condition that the flame temperature is as high as 950-. The cable has the characteristics of high temperature resistance, corrosion resistance, no aging, water resistance, explosion resistance, magnetic interference resistance, no smoke, no toxicity and the like, can ensure the safety of the public and buildings to the greatest extent, and is a safe and environment-friendly cable with the highest comprehensive performance, which can meet the increasingly stringent safety requirements and modern design specifications of the state at present.

The flexible mineral insulation metal sheath cable generally uses a fire-resistant mica tape to be continuously wrapped as an insulating layer, but due to the characteristics of mica tape materials, if the mica tape is not well sealed in the production, transportation and use processes, the moisture is easily caused, and once the mica tape serving as the insulating layer is wetted, the unqualified condition of the insulation resistance is caused. In the prior art, aiming at the condition that the insulation resistance is unqualified, the whole cable with the unqualified insulation resistance is usually scrapped, and the method has the disadvantages of huge raw material waste, large labor hour waste and equipment production time occupation; or the mica tape is put into an oven for drying treatment before being used, although the proposal avoids a great deal of waste, the mica tape after being dried at high temperature has stronger moisture absorption capacity, and meanwhile, the connection requirement of the upper process and the lower process of the treatment method is strict, and the energy consumption of high-temperature drying equipment is higher, thus leading to higher production cost.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for repairing unqualified insulation resistance of a flexible mineral insulated metal sheathed cable, which can be used for repairing the problem of unqualified insulation cable of the flexible mineral insulated metal sheathed cable, effectively reduces scrap and reduces production cost.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the method for repairing the unqualified insulation resistance of the flexible mineral insulation metal sheath cable comprises the following steps:

(1) detecting whether the insulation resistance of the cable is qualified or not to obtain the cable to be repaired, wherein the insulation resistance of the cable is unqualified;

(2) one end of the cable to be repaired is sealed by a thermal shrinkage sealing cap with a valve, and the other end of the cable is not sealed;

(3) blowing nitrogen into the cable to be repaired through the air valve, and blowing the cable to be repaired;

(4) after blowing for 4-6 hours, detecting whether the insulation resistance of the cable subjected to the blowing treatment is qualified or not again, and repeating the operation of the step (3) and the step (4) if the detection result is unqualified;

(5) and when the insulation resistance detection result shows that the insulation resistance is qualified, indicating that the repair is finished, and sealing and installing heat-shrinkable end sockets at two ends of the cable to obtain the cable which can be normally used after the repair.

The nitrogen gas blown in the step (3) is high-purity nitrogen gas. The high-purity nitrogen has good dehumidification capacity, and can realize dehumidification treatment of mica tapes in the cable as high as possible and improve repair efficiency.

And (4) connecting a nitrogen bottle filled with high-purity nitrogen to the valve in the step (3), and blowing nitrogen into the cable to be tested by opening a switch on the nitrogen bottle. And realizing the stable input of nitrogen.

And arranging a heating device outside the nitrogen cylinder, heating the gas in the nitrogen cylinder to 40-60 ℃ by the heating device, opening the nitrogen cylinder, controlling the input pressure of nitrogen to be 0.3-0.5 Mpa, and blowing the cable to be repaired. The dehumidification capacity effect of the high-purity nitrogen with the temperature of 40-60 ℃ is obvious, the input pressure of the nitrogen is controlled to be 0.3-0.5 Mpa, the full utilization of the dehumidification capacity of the nitrogen can be realized, the energy utilization efficiency is improved, and the dehumidification effect is further improved.

Compared with the prior art, the invention has the advantages that: the nitrogen is a medium with drying capacity, and the cable to be repaired is subjected to nitrogen blowing treatment, so that moisture on the moistened mica tape can be taken away and output outwards through the nitrogen, and the moisture removal treatment of the mica tape and the unqualified repair of the insulation resistor are realized; the heat-shrinkable sealing cap with the air valve provides an independent input channel for inputting nitrogen, so that other gases (such as water vapor and the like) in the air are prevented from being brought into the cable in the air blowing process, and the air blowing and moisture removing efficiency is ensured; after the detection is finished, the two ends of the cable are sealed and provided with the heat-shrinkable end sockets, so that the interior of the cable is sealed, and the condition that the insulation resistance fails again and is unqualified due to the fact that the mica tape in the cable is damped again is avoided; the operation is simple and convenient, the scrap rate is effectively reduced, and the production cost is reduced.

Detailed Description

The present invention is described in further detail below.

The method for repairing the unqualified insulation resistance of the flexible mineral insulation metal sheath cable comprises the following steps:

(1) detecting whether the insulation resistance of the cable is qualified or not to obtain the cable to be repaired, wherein the insulation resistance of the cable is unqualified;

(2) one end of the cable to be repaired is sealed by a thermal shrinkage sealing cap with a valve, and the other end of the cable is not sealed;

(3) blowing nitrogen into the cable to be repaired through the air valve, and blowing the cable to be repaired;

(4) after blowing for 4-6 hours, detecting whether the insulation resistance of the cable subjected to the blowing treatment is qualified or not again, and repeating the operation of the step (3) and the step (4) if the detection result is unqualified;

(5) and when the insulation resistance detection result shows that the insulation resistance is qualified, indicating that the repair is finished, and sealing and installing heat-shrinkable end sockets at two ends of the cable to obtain the cable which can be normally used after the repair.

In this embodiment, the nitrogen gas blown in the step (3) is a high-purity nitrogen gas. The high-purity nitrogen has good dehumidification capacity, and can realize dehumidification treatment of mica tapes in the cable as high as possible and improve repair efficiency.

In this embodiment, a nitrogen gas cylinder filled with high-purity nitrogen gas is connected to the gas gate in step (3), and the blowing of nitrogen gas into the cable to be tested is achieved by opening a switch on the nitrogen gas cylinder. And realizing the stable input of nitrogen.

In the specific embodiment, a heating device is arranged outside the nitrogen cylinder, the gas in the nitrogen cylinder is heated to 40-60 ℃ by the heating device, then the nitrogen cylinder is opened, the input pressure of the nitrogen is controlled to be 0.3-0.5 Mpa, and the cable to be repaired is subjected to blowing treatment. The dehumidification capacity effect of the high-purity nitrogen with the temperature of 40-60 ℃ is obvious, the input pressure of the nitrogen is controlled to be 0.3-0.5 Mpa, the full utilization of the dehumidification capacity of the nitrogen can be realized, the energy utilization efficiency is improved, and the dehumidification effect is further improved.