Application of abrasive particle analysis technology in fault diagnosis of grease lubrication equipment

Cranes, aerial vehicles, and overhead cranes are commonly referred to by people as cranes, and traveling cranes are basically the same as what we now refer to as cranes. It is a mechanical equipment used for material handling operations. Through the combined movement of the working mechanism, the material is lifted and moved within a certain range of space, completing the work cycle of material handling.
One of the components of the crane is the drum coupling, which is a new type of flexible coupling mainly used for connecting the reducer output shaft of the lifting mechanism in lifting equipment with the steel wire rope drum. It is also suitable for other similar mechanical equipment that transmits torque and bears radial load, but cannot be used as a transmission that needs to bear axial load. The drum coupling is a very important equipment in driving, which bears a large load and operates at a relatively low speed. During operation, it often experiences local pitting, fatigue peeling, and other faults. When equipment malfunctions suddenly, it usually causes significant economic losses, and repairing it often requires a lot of manpower and material resources. Therefore, there is a need for new technological means to monitor its status and diagnose faults.
The drum coupling also uses lubricating grease for lubrication. Due to the viscous and semi solid nature of the lubricating grease, it cannot circulate and the abrasive particles generated during use remain in their original position, making it difficult to collect representative oil samples. At the same time, due to the sealing function of lubricating grease, there are often a large number of external pollutants in the collected samples, which brings great difficulties to the abrasive particle analysis of lubricating grease. In addition, the high content of thickener in lubricating grease makes it difficult for conventional organic solvents to dissolve all the organic matter in the grease without affecting the appearance and morphology of the abrasive particles.
Due to the above characteristics, ordinary methods cannot perform quantitative and qualitative analysis of metal particles in lubricating grease. So it is necessary to adopt new methods to unify the wear analysis method of lubricating grease with the relevant analysis methods of lubricating oil, in order to monitor the status and diagnose faults of grease lubrication equipment.
Quantitative analysis
The concentration of metal elements in lubricating grease can be quantitatively analyzed through spectral analysis.
First, pre-treat the lubricating grease with a special solvent to make it a liquid solution, and then use an oil spectrometer to measure its elemental content. In practical operation, the main analysis is generally the elemental content of wear metals such as iron, copper, chromium, and nickel.
Conduct wear analysis and inspection on the coupling of the crane drum, and take samples at two time points to determine the content of the main metal elements. Check the analysis results of the two samples to see if any element content is abnormally high, and analyze and speculate whether there is abnormal wear on the coupling itself. If the iron element content is abnormally high, it indicates that there is abnormal wear.
Qualitative analysis
The shape and composition of metal particles contained in lubricating grease can be determined through ferrography technology.
Ferrographic analysis involves pre-treatment of lubricating grease into a liquid solution, followed by the use of a rotating ferrograph to prepare a spectrum, and then observing the morphology of abrasive particles through the ferrograph. The purpose of optical observation of wear particles is to observe the number, size, Surface finish, contour and gloss of various particles on the ferrograph plate by using the ferrograph microscope and its accessories, so as to analyze and judge the wear state and development trend of the machine. Therefore, among the numerous particles on the ferrograph, it is important to observe and analyze the larger and more numerous particles, especially various abnormal wear particles.
Further abrasive particle analysis of the sample showed that there were a large number of metal oxide particles and medium to small sized steel abrasive particles in the lubricating grease. If there were nearly 100 * 70 microns of flake like abrasive particles, it indicates a large amount of metal oxide, indicating poor lubrication on the friction surface. The appearance of a large number of abrasive particles indicates abnormal wear of the equipment due to poor lubrication effect, and on-site inspection is needed to replenish the lubricating grease as soon as possible, To improve the lubrication status of the friction pair. If ferrography analysis shows the presence of a large number of red oxide particles in the detected lubricating grease, it indicates that the friction pair at the measuring point has severe corrosion. This monitoring point can be tracked and monitored to determine whether the coupling buffer has severe poor lubrication or abnormal wear. It is recommended to focus on checking the equipment wear condition.