The traditional detection method and online automatic monitoring system for steel wire rope are compared. The principle, composition and application examples of the online automatic monitoring system for steel wire rope are introduced. From the practical application effect of the system in Hulonggou Mine of Wajinwan Coal Industry Company of Datong Coal Mine Group, it is shown that the automatic monitoring system has successfully solved the problems of online automatic monitoring and real-time management of the hoisting winch steel wire rope.

    CLC No.: TD53 Document Code: A Article Code: 1672-3791 (2009) 08(c)-0010-01

    As an important lifting, lifting, and transportation equipment in the "highly dangerous construction," steel wire rope has always been regarded as the "lifeline" in these fields. For a long time, due to the lack of scientific and reliable testing equipment, the use of steel wire rope has always been a "blind spot" or "danger source" in major equipment management. In order to ensure the safety of using steel wire rope, the units generally use manual detection or regular replacement of steel wire rope. Due to the wear and corrosion of steel wires caused by steel wire cross-sectional area reduction; due to fatigue, surface hardening, corrosion caused by internal changes in steel wire performance; improper use caused by rope deformation, etc. In service steel wire rope may be damaged by single wire fracture, corrosion, wear, disorder and other injuries, all kinds of damage will cause the failure of steel wire rope. Due to the importance of steel wire rope use and the structural performance characteristics of steel wire rope, when a serious defect occurs in one place in the steel wire rope, the entire steel wire rope will be scrapped. Therefore, once the steel wire rope fails, it will be irrepairable.

　　It is generally recognized in technical terms that the critical point for determining whether a steel wire rope is safe is a strength loss of 15%. A US authority once conducted a survey of 8,000 steel wire rope testing stations and application sites worldwide, and the results showed that 10% of the steel wire ropes in use had a strength loss of more than 15% and were in a dangerous state, while 2% of the steel wire ropes in use had a strength loss of more than 30% and were in an extremely dangerous state. Approximately 70% of the steel wire ropes that were forced to be replaced had little or no strength reduction. This caused a great waste. The rope that should have been replaced was not replaced, while the rope that should not have been replaced was forced to be replaced. This is all due to the imperfect and unscientific monitoring and management methods of steel wire rope.

　　At present, most coal mines in China still use manual detection for the steel wire rope of the hoisting winch. This method has the following two drawbacks 

　　High power consumption during start-up: Manual detection of steel wire rope uses visual inspection and hand feeling, with a running speed of 0.3-0.5m/s. If there is any suspicion, the inspection needs to be stopped and a caliper is used to measure it. For a certain section of steel wire rope with heavy oil sludge, it needs to be cleaned before inspection, and testing needs to be conducted once a day. Taking Longhugou Mine of Datong Coal Mine Group as an example: The auxiliary inclined shaft hoist winch steel wire rope is 770m long, and the motor power is 1000kw. Each detection of steel wire rope takes about 1 hour, resulting in a waste of 300-400 hours of start-up power consumption in just one year. This consumes 400,000kVA of electricity.

　　Unreliable data: During use, steel wire ropes should be lubricated at least twice a month. Before lubrication, use a steel wire brush to remove the dirt on the steel wire rope and clean it with kerosene. Then, heat the lubricating oil to above 800°C and dip the steel wire rope into it to make the lubricating oil penetrate into the core of the steel wire rope. Manual detection can only partially detect external injuries to the steel wire rope, but cannot detect internal breaks, wear, corrosion, especially fatigue and other conditions of the steel wire rope. Therefore, many significant hidden dangers are difficult to find.

　　The online monitoring of wire rope defects such as broken wires and wear has been studied for a century. Due to its unique structure of thin and long materials, ordinary electronic instruments have difficulties in processing data and analyzing them in real time. Even if the most advanced sensors are used to collect signals, misdetection and missed detection are inevitable.

　　In recent years, the expensive non-destructive testing equipment for wire rope that was imported from countries such as the United States, the United Kingdom, Japan, and Canada has mostly been abandoned or is only limited to laboratory research. The use of real-time online monitoring for wire rope is still a technical gap that has yet to be filled globally.

　　The emergence of an online automatic monitoring system for wire rope has made it possible to replace manual inspection with scientific instruments. The online automatic monitoring system for wire rope maximizes the elimination of human factors. After the system is pre-adjusted by technical personnel, it enters into an automatic calibration and automatic detection mode, and the detection results are stable and reliable.

　　The principle of the online automatic monitoring system for steel wire rope is to select a monitoring point in the operating path of the wire rope to complete real-time monitoring of the maximum stroke as much as possible. When a dangerous signal is encountered during monitoring, it is transmitted to the equipment operating system in the first time, and issues an acoustic-visual alarm and can also be set to automatically or manually stop the equipment for emergency treatment to ensure safe operation.

　　The online automatic monitoring system for steel wire rope mainly consists of a modal weak magnetic loading device, a mode combination detection system, a stable state operation and maintenance device, a multi-function data acquisition and conversion workstation, an acoustic-visual warning system, and a terminal program main command control main station. The detection process is as follows: firstly, the weak magnetic loading device completes the weak magnetic loading of the measured steel wire rope to make it in a stable state ready for testing; secondly, the high-performance sensor monitoring system completes the extraction of the entire state information of the measured steel wire rope and outputs the original detection information; the sensor should be installed at the position with the least swing of the steel wire rope. The installation should have certain flexibility and use a suspended fixed method to avoid the steel wire rope from moving in the probe; only the steel wire rope that passes through the sensor can be detected. Therefore, when there is a detection dead zone, multiple point detection should be selected. Keep away from heat sources, magnetic sources, and other instruments that are affected by strong magnetic fields. The multi-function data acquisition and conversion workstation receives the original detection information and completes the specified data conversion to achieve preliminary processing and information storage of the original data; and transmits real-time damage signals of the规格书 during operation to the main control center through wired or wireless communication transmission methods.

　　According to the provisions of the MT/T970-2005 "Non-destructive quantitative detection method and judgment rules for steel wire rope (cable) online" of the People's Republic of China coal industry standard, the processing results of the multi-function data acquisition and conversion workstation provide early warning signals to judge the safety status of the steel wire rope according to the degree of damage.

　　Datong Coal Group Wajinwan Coal Industry Company Hulonggou Mine applied the steel wire rope online automatic monitoring system to completely eliminate various drawbacks of manual detection and avoid the occurrence of wire breaking accidents. The automatic monitoring system plays a very important role in ensuring safe production.

　　At the same time, the automatic monitoring system also brings considerable economic benefits to Hulonggou Mine. The detection energy consumption can be saved by nearly 300,000 yuan, and the steel wire rope will not be forced to replace it due to the automatic detection system, which reduces the cost by 600,000 yuan. The downtime detection time is reduced by 4/5, creating a profit of 1 million yuan. The total annual savings are over 2 million yuan, while providing reliable guarantees for safe use of steel wire rope.

　　The steel wire rope automatic online monitoring system plays a very important role in the use and maintenance of lifting steel wire rope, providing technical support and basis for scientific and systematic management of lifting steel wire rope, ensuring work efficiency and eliminating potential safety hazards. It scientifically reduces costs and creates considerable economic benefits.

　　About the author: Zhu Dagen (1972- ), male, assistant engineer of Datong Coal Mine Group Wajinwan Coal Industry Company.