1 the introduction
Improving the reliability and utilization rate of coal mine equipment is one of the keys to improve coal mine production.Traditional fault maintenance and regular maintenance methods can not meet the requirements of production development.Due to the formation of modern centralized production mode, equipment upsizing and automation, state maintenance system based on equipment state monitoring and fault diagnosis technology is an advanced and effective maintenance method.
So-called equipment state maintenance way, it is through continuous or periodic for equipment running status monitoring, diagnosis and forecast equipment failure in time, establish and improve the equipment state archives, determine the maintenance time and content, and to prepare maintenance unit need to replace parts or components, in order to shorten downtime and reduce maintenance costs, improve equipment utilization.
2. Disadvantages of regular maintenance
Limitations of traditional periodic maintenance can be summarized as follows:
(1) unnecessary maintenance may increase the failure rate
According to statistics, frequent regular overhaul will increase the failure rate.Achieving state maintenance can reduce failure rate by 75%.
(2) may increase maintenance costs, resulting in the waste of working hours of equipment regardless of the state of good or bad, all mechanical maintenance according to the plan, is bound to produce excess maintenance, resulting in waste.
(3) reduced the operation rate and production efficiency of the equipment.
(4) lead to the rigidity of maintenance personnel's thinking and poor diagnosis and maintenance of "abnormal situations" in various states.
Application of equipment state maintenance technology in mines at home and abroad
(1) overseas application examples
Australia's Bougainville copper mine, which has been producing steadily since January 1972, is one of the most economically profitable large open-pit mining companies in the world.The mine has always attached great importance to the application of equipment status monitoring and fault diagnosis technology, and implemented the equipment status maintenance system to constantly improve the utilization rate of equipment.
The mine monitoring center is equipped with the most advanced monitoring and diagnostic equipment and a special sampling vehicle.More than 3000 lubricating oil and bearing vibration test sampling points have been set up for relatively advanced large-scale equipment such as 13m shovel, 154t dump truck, +250 rotary drill, ball mill and crusher, etc., with an average of about 10 oil samples and 935 test items tested every day.All the analysis results are input into the computer system before 4pm every day, and the equipment executive manager determines the maintenance time and content of the equipment through the results reported by the computer system.For large fixed equipment, the monitoring center assigns special personnel to collect vibration signal on the spot, conduct frequency spectrum analysis and pattern processing indoors, and timely alarm if any abnormality is found.
(2) benefits brought by maintenance of equipment status
In the management of mining equipment using state maintenance, can bring a variety of benefits: (1) improve the equipment completion rate.For example, the completion rate of drilling RIGS was increased to 97.4%.The completion rate of ball mill was increased to 99%.The completion rate of crusher was increased to 98.1%.(2) through status monitoring to find hidden dangers in time, take measures to avoid the occurrence of major accidents;(3) extend the service life of the equipment, can appropriately extend the overhaul cycle;(4) save oil;(5) shorten the maintenance downtime of equipment, increase the effective operation time of equipment.
(3) application in China's coal mines
At present, equipment status monitoring and fault diagnosis technology has been widely used in modern enterprises, such as petroleum, chemical, electric power, metallurgy industry equipment management.Since the maintenance cost accounting of China's coal enterprises has not been placed in an important position, the state maintenance technology has not been widely used in the coal industry.Only a few enterprises in China have applied equipment status monitoring and fault diagnosis technology in coal production, and achieved good results.
Xuzhou mining group sanhejian coal mine adopts state maintenance of only 1a, accurately predicts several major potential faults, ensures equipment safety, and saves 1.72 million yuan of various costs.Good economic and social benefits have been achieved.For example, the unbalanced fault of centrifugal fan has been successfully solved.G4 -- 73-11n028 type D centrifugal fan is composed of synchronous motor, axle box and impeller.TD 116/64 -- 10 motor, speed 600r/min, power 800kW.September 1998.During the regular switching operation of the two ventilators, it was found that the vibration of the two ventilators was severe.Radial vibration is almost three times that of a fan.The peak value of no. 4 measurement point reached 14.02mm/s.Exceeding the permitted scope stipulated in ISO2372.The temperature records at each measuring point show that the temperature does not change significantly, which eliminates the possibility of local bearing failure.The radial waveform of no.4 measuring point with the strongest vibration was collected by using the vibration 903 digital collector, and its spectrum diagram was obtained.It is found that it is based on power frequency and frequency multiplier, and the whole spectrum is in the shape of a fir tree.It can be inferred that the fan rotor is out of balance.Using the vibration pass SDES expert system diagnosis conclusion: (1) vibration spectrum to the base frequency component is the main, the rotor is estimated to exist dynamic imbalance or bending, it is recommended that the rotor into the dynamic balance.If the vibration is sudden increase, there may be rotor parts or scaling off;(2) large vibration and blade or fluid parameters, based on the balance of the fan impeller correction, add the weight of 6606g after the overall decline in vibration, successfully eliminate the hidden trouble.
4 conclusion
The development of modern technology.As mechanical equipment becomes more and more automatic and complicated, the precision is also constantly improved. Based on equipment state monitoring and fault diagnosis technology, state maintenance is a necessary condition to improve equipment management and maintenance modernization level. The huge economic benefits will be recognized by more and more coal enterprises.