Application of wear particle analysis technology in fault diagnosis of grease lubricated equipment
Crane, aerial vehicle and crown block are all commonly known to cranes. The driving is basically the same as what we call cranes now. It is a mechanical equipment used for material handling. Through the combined movement of working mechanism, the material is lifted and moved within a certain space to complete the work cycle of material handling.
Drum coupling is a new type of flexible coupling, which is mainly used for the connection between the output shaft of reducer and steel wire rope drum of hoisting mechanism in hoisting equipment, and also suitable for other similar mechanical equipment which not only transmits torque but also bears radial load, but it can not be used as transmission to bear axial load. Drum coupling is a very important equipment in the driving, which bears large load and low running speed. It often occurs some faults such as local pitting and fatigue stripping during operation. When the equipment breaks down, it will cause great economic loss, and it often takes a lot of manpower and material resources to repair it. Therefore, new technical means are needed to monitor and diagnose the status of the system.
The drum coupling is also lubricated by grease. Because the grease belongs to viscous semi-solid material, it cannot circulate, and the grinding particles produced in the process of use are basically in the original position, so it is difficult to collect representative oil samples. At the same time, because the grease also has the function of sealing, there are a lot of external pollutants in the samples collected, which makes it difficult to analyze the grinding particles of the grease. The content of thickener in the grease is very high. It is difficult for conventional organic solvents to dissolve all the organic matter in the grease without affecting the appearance of the abrasive particles.
Because of the above characteristics, the general method can not complete quantitative and qualitative analysis of metal particles in grease. Therefore, a new method is needed to unify the wear analysis method of grease with the relevant analysis method of lubricating oil to monitor the status of grease lubrication equipment and diagnose the fault.
The concentration of metal elements in grease can be quantitatively analyzed by spectral analysis.
The grease was pretreated with special solvent to make it liquid solution, and then the element content was determined by oil spectrometer. In the practical operation, the elements content of wear metal such as iron, copper, chromium and nickel are generally analyzed.
The wear analysis and detection of the coupling of the driving drum shall be conducted, and sampling shall be conducted at two time points to determine the content of main metal elements. It is seen whether the content of any element is abnormally high in the analysis results of the two sampling, so as to analyze and infer whether the coupling itself has abnormal wear. If the iron content is abnormally high, it indicates that there is abnormal wear.
The shape and composition of metal particles in grease can be determined by ferrography.
The ferrography analysis is that the grease is pretreated into liquid solution, then the rotating Ferrograph is used to prepare the spectrum sheet, and then the grinding particle morphology is observed by the Ferrograph. The purpose of optical observation of abrasive particles is to observe the number, size, surface texture, outline and luster of various particles on the Ferrograph by using ferrography microscope and its accessories, so as to analyze and judge the wear state and development trend of the machine. Therefore, the large size and large number of particles, especially the abnormal wear particles, should be observed and analyzed in many particles on the Ferrograph.
Further analysis of the sample shows that there are a lot of metal oxide particles and medium and small size steel abrasive particles in the grease. If there is nearly 100 * 70, the grinding particles are nearly 100 * 70 The micro flake grinding particles indicate that there are a lot of metal oxides, which indicates that there is poor lubrication on the friction surface and the appearance of a large number of abrasive particles, which indicates that the equipment has abnormal wear due to poor lubrication effect. It is necessary to supplement the grease as soon as possible by spot inspection on site to improve the lubrication state of friction pair. If the ferrography analysis shows that there are a large number of red oxide particles in the lubricating grease, it indicates that the friction pair of the measuring point has serious corrosion. The monitoring point can be tracked and monitored to determine whether the coupling buffer has serious poor lubrication or serious abnormal wear, and it is suggested to focus on the inspection of the equipment wear condition.