Abstract: Elevator

　　, as a symbol of human material civilization, is widely used in shopping malls, hotels, office buildings, and residences. It has become an indispensable means of transportation for people's production and life and is indispensable for the rapid development of economy and society. Carrier. As a special equipment with mechatronics, elevators have inherent risk attributes. The inspection and testing of elevators not only meets the requirements of the "Special Equipment Safety Law of the People's Republic of China", but also the work of installation, transformation, repair, maintenance, use management and other links. As an important part of ensuring the safe operation of elevators, steel wire ropes bear a major responsibility for quality verification. This paper expounds the importance of elevator wire rope detection, and mainly explores the monitoring and maintenance methods of elevator wire ropes.

　　Key words: elevator: steel wire rope; inspection and maintenance;

　　importance Elevator is a common large-scale equipment, widely used in high-rise buildings such as shopping malls, hospitals, residential and office buildings, maintaining elevator safety is an important job, because Once a problem occurs, it is likely to be a major safety problem, resulting in property loss, or even casualties. The steel wire rope is the most critical suspension device in the elevator components. Almost all the quality of the elevator car needs to be borne by the steel wire rope. At the same time, the steel wire rope is also a key component to move the car up and down. The friction between the wire rope and the elevator sheave is the driving force for the overall lift of the elevator. Therefore, it is no exaggeration to say that the quality assurance of the wire rope is to ensure the safety and stability of the elevator car. The key aspects of operation must be paid special attention. At present, the quality of the wire rope can be basically guaranteed, as long as it is used under normal conditions, the wire rope is rarely broken. Usually, the safety problems of elevator wire ropes include corrosion and breakage of elevator wire ropes in the air, the diameter of elevator wire ropes becomes smaller, and the maintenance of elevators is not in place. happened.

　　1. Common problems of elevator wire rope safety

　　(1) Corrosion and fracture of elevator wire ropes During the actual operation of the elevator, the wire ropes have always been exposed to the air. When the iron in the steel wires reacts chemically with the oxygen and moisture in the air, the steel wire ropes will be produced to varying degrees. Corrosion of the elevator hoisting machinery will reduce the strength of the steel wire rope and greatly reduce the service life of the wire rope. It is necessary to regularly check the corrosion of the wire rope, repair and replace it in time, reduce the possibility of elevator failure, and try to avoid the occurrence of safety accidents.

　　Elevator wire ropes are composed of many types of steel wires. The performance and safety of all these steel wires affect the overall safety of the wire rope. However, during the operation of the elevator, the wear, corrosion and deformation of the steel wires are inevitable, so Attention must be paid to the maintenance of elevator equipment to ensure the safety of the elevator during its service life.

　　(2) The diameter of the elevator wire rope becomes smaller As the

　　elevator wire rope is used as a device for pulling the elevator, due to various tensions in the working process, when the elevator is overweight and exceeds the maximum tension that the wire rope can bear, the yield strength of the wire rope is reached, and the deformation of the wire rope will not be affected. It can be restored, so the diameter of the wire rope will become smaller with the increase of service life, which will eventually lead to cracks or even breakage of the wire rope, resulting in elevator safety accidents.

　　(3) Insufficient attention to elevator wire ropes

　　Elevators are frequently used, and elevator wire ropes are easily worn, corroded and aged. Insufficient maintenance of elevators is the main reason for elevator failures and safety accidents. According to the survey, elevator accidents ranked second in the national special equipment safety accident ranking in 2019. , a total of 33 accidents occurred, accounting for 25.83% of the accidents, resulting in 29 deaths, accounting for 24.37% of the deaths in special equipment accidents. According to analysis, the main reasons for the accident are: first, improper use and management, of which illegal operations are the main reason The specific manifestations are the illegal operation of operators, improper operation or even unlicensed operation, lack of maintenance, and poor management: the second is caused by quality and safety defects in the process of equipment manufacturing, maintenance, installation and disassembly, and operation; 9 of the elevator accidents were Violation of regulations and improper operation, 1 accident was unlicensed operation, 4 failures of safety components and equipment defects, 2 improper rescues, and 8 poor maintenance and safety management. These elevator safety accidents have seriously threatened our life safety. Enterprises should pay more attention to elevator safety, increase the inspection of elevator hoisting machinery wire ropes in the later period, and pay attention to maintenance and maintenance.

　　2. Elevator wire rope detection technology

　　Scrap conditions and inspection methods

　　There is no time limit for scrapping the elevator traction wire rope. However, there is a scrapping standard. TSGT7001-2009 stipulates: When one of the following conditions occurs, the traction compensation wire rope should be scrapped: ①Cage

　　distortion, rope core extrusion, kink, partial flattening, bending: ②Broken wires scattered in the whole For a steel wire rope, the number of broken wires in a single strand in any lay length is more than 4: or the broken wires are concentrated in a certain part or one strand of the wire rope, and the total number of broken wires in a lay length is more than 12 (for a wire rope with 6 strands) Or more than 16 (for the wire rope with 8 strands):

　　③The diameter of the wire rope after wear is less than 90% of the nominal diameter of the wire rope.

　　Inspection methods:

　　(1) Visual inspection and manual inspection

　　Visual inspection and manual inspection are the most basic methods to detect the wear, corrosion and diameter of the elevator wire rope, as well as the fracture of the surface steel wire structure, and can have a preliminary judgment on the wear condition of the elevator wire rope. First of all, the traction force of the wire rope is checked. The experiment proves that the influence of the dynamic tension force on the service life of the wire rope is far greater than that of the static tension force, and the uneven force on the wire rope of each elevator hoisting machinery also seriously affects the service life of the wire rope and the safety of the elevator. Therefore, when carrying out elevator safety maintenance inspections, it is necessary to carefully check and adjust the stress of the elevator wire ropes to ensure that the tension of each wire rope is within 5% of the difference

　　, so as to avoid individual wire ropes due to gravitational force. Badly worn.

　　Secondly, the broken condition of the wire rope should be checked. The broken wire of the wire rope caused by different reasons has different appearances. Experienced elevator maintenance personnel can judge it through visual inspection and manual inspection. Among them, the broken wire caused by wear occurs in The outer layer of the steel wire rope of the elevator hoisting machinery is flat at the break, which is formed by the continuous friction between the steel wire rope and the wheel groove during the operation of the elevator. The type of rope groove that is suitable for the wire rope should be calibrated during the installation process, so that the center of the rope groove and the center of the wire rope are coincident, so as to avoid the situation that only one side of the wire rope is rubbing against the rope groove: the fracture of the broken wire caused by corrosion is not uniform. Irregularly pointed, the surface of the wire rope will produce dense bumps and convexities due to oxidation reaction. When these pits cover the wire rope and are visible to the naked eye, it is necessary to consider replacing the wire rope and stop the loss in time; the broken wire caused by overload, that is, the elevator The wire rope is broken due to the overloaded tension. This kind of fracture is similar to the cup mouth, which can be visually detected. The surface of the wire rope will be seriously deformed, and the wire rope core will even be exposed. The lubricating oil of the rope core flows out, and the wire rope is still There is a phenomenon of curling and accumulation, in this case, it is necessary to replace the new wire rope in time.

　　It is worth noting that the current visual inspection and manual inspection methods used by elevator maintenance personnel are biased towards using experience to conduct maintenance inspections. In foreign countries, professional equipment is used to detect elevators. Obviously, it is more accurate and scientific to use equipment to detect problems existing in elevators. In addition to the horizontal comparison, let's take a vertical look. The so-called vertical comparison refers to the comparison between the new generation and the old generation of elevator maintenance personnel. The new generation of elevator maintenance personnel uses less experience and is more willing to use the established laws in books. The knowledge and formula theorems of the older generation of elevator maintenance staff can be flexibly adapted to the problems of the elevator with their years of experience. It can be said that when using the visual inspection method and the manual measurement method, the working methods of the older generation of elevator workers are more suitable for using these two methods, while the new generation of elevator maintenance workers may need to change their flexibility in maintenance, rather than Rigidly rely on the knowledge learned in the textbook.

　　(2) Tool measurement

　　Under normal operation, macroscopically check the status of the wire rope, and when suspicious, use a wire rope flaw detector to detect the full length of the wire rope or spot test in sections: measure and judge the change in the diameter of the wire rope. When measuring, take two points at least 1m apart. , Measure twice in the direction perpendicular to each point at each point, and the average value of the four measurements is the measured diameter of the wire rope. Measuring the diameter of the wire rope can timely find out whether the wire rope is often overloaded and whether the force of each wire rope is uniform.

　　In order to ensure the safety of the elevator, the safety hazards such as wear, corrosion and fracture of the elevator hoisting machinery wire rope can be found in time during the elevator maintenance work. The detection method technology is electromagnetic detection technology. For the inspection of wire rope breakage and corrosion, the magnetic leakage detection method is used, and a special probe is used to locally magnetize the wire rope. When the wire rope has problems such as broken wire and corrosion, some characteristics of the magnetic field The parameters will change, and the changing value of the parameters is the key factor in judging the defects of the wire rope. This electromagnetic detection technology is more accurate than the visual inspection method and manual inspection method for the damage of the wire rope, and the obtained information is more detailed. It can also conduct qualitative and quantitative analysis of the corrosion and fracture of the wire rope, and even obtain The detailed information on the number of broken wires and the specific conditions of the cross-section will help the technicians to have a comprehensive and accurate understanding of the condition of the elevator wire rope.

　　But the electromagnetic detection technology is still not perfect, there are many problems and deficiencies. For example, during electromagnetic detection, the output signal is easily affected by external environmental factors, which greatly reduces the accuracy of the detection results. Once the detection personnel are careless and do not pay attention to the external environmental conditions, information distortion is likely to occur, and wrong information can easily lead to Wrong judgment is very unfavorable for elevator safety: Secondly, electromagnetic detection technology requires more equipment, high quality, and it is not easy to carry. When testing elevator wire ropes in real life, it is inconvenient for testing technicians to carry and use, and it is not easy to carry out testing operations: There is also electromagnetic detection technology that cannot detect the damage of small elevator wire ropes, and because it is a long section of wire rope to detect, if the degree of damage to the detected wire rope is less than the detection length, the small damage problem is even more difficult to find. These undetected small damage and fatigue of the wire rope will lay a hidden danger for the safety of the elevator.

　　3. Maintenance of elevator wire ropes

　　(1) Regularly lubricate the wire ropes When the

　　elevator is working, when the wire ropes are bent under the action of tension, the relative positions of the small wires move, resulting in greater friction, so it is necessary to ensure To ensure the safety of elevators and prolong the life of elevator wire ropes, it is necessary to lubricate the wire ropes regularly, even if the elevator wire ropes have undergone a special lubrication process during production to ensure that all wire surfaces are covered with lubricating oil, but long-term use produces Affected by wear and dust, the original lubricating oil will be lost, and the lubricating oil has a good protective effect on the wire rope, which can isolate the air and prevent the wire rope from oxidizing and corroding, so regular lubrication work is essential. When using, pay attention to the amount of lubricating oil to be used evenly and not excessively, otherwise, the wire rope will slip in the rope groove, the traction force will be small, and the elevator safety accident will occur.

　　(2) Regularly clean the wire rope

　　It is necessary to ensure that the surface of the wire rope is cleaned every six months, because the lubricating oil is easy to combine with some dust, and the dirt is attached to the surface of the wire rope. These dirt not only accelerate the wear of the wire rope, but also hinder the penetration of new lubricating oil. If the dirt is cleaned regularly, the diameter of the wire rope will become larger and larger due to these attachments, and it will be easier to break during the mutual extrusion process, and it is not conducive to the electromagnetic detector inspection. It is best not to use some liquid detergents to clean the wire rope, because these detergents are generally degreasing, which will destroy the grease inside the wire rope. Use brushes, cotton yarn and air compression methods. After cleaning, also Carry out some lubricating work on the wire rope, so that it is completed. The unlubricated wire rope wears more seriously, which will greatly reduce the service life of the elevator.