Shot blasting machine equipment is a steel pipe external surface rust removal equipment designed and manufactured according to the needs of the factory's own pipeline anti-corrosion production and construction, as well as to better improve the rust removal quality of the steel pipe surface.
When the workload of anti-corrosion projects is large, due to the high operating rate of equipment and the immature experience in manufacturing, installation, maintenance, and design of equipment, the core component of the shot blasting machine, the shot blasting machine, often stops due to malfunctions, resulting in the entire anti-corrosion operation line being shut down.
After inspection, maintenance and analysis, it was found that the main causes of the malfunction of the shot blasting machine equipment were bearing damage caused by high temperature and bending deformation due to severe wear of the shaft, which were caused by vibration under the action of high-speed rotating blades. Not only is replacement and maintenance very inconvenient, but it also wastes a lot of manpower and increases costs, directly affecting the production and construction progress. Corresponding solutions have been taken to address the issues with the device.
1. Cause analysis
1) Unreasonable selection of bearing models
The main reason for the high temperature and easy burning of bearings is that two bearings on the same shaft cannot maintain good coaxiality, resulting in an angle between the inner and outer rings of the bearing that is greater than the allowable angle of the bearing, which constantly changes the working conditions of the bearing and causes the temperature of the bearing to rise during operation until it is damaged.
2) There are defects in the design of the shot blasting machine box and bearing seat
The positioning structure of the housing and bearing seat is not designed, and the installation accuracy of the bearing seat is determined by the actual operational ability of the assembly personnel, which cannot guarantee the installation accuracy of all bearing seats. At the same time, during the operation of the shot blasting machine, if some bolts become loose due to the different degrees of wear of the four blades in a group, such as vibration, it is also possible to change the original installation accuracy position of the bearing seat, increase the angle between the inner and outer rings of the bearing, and continuously change the working conditions of the bearing, resulting in an increase in bearing temperature until it is damaged.
3) The structural form of the positioning protective cover is not ideal
The shot blasting machine box is composed of one shot blasting chamber and two abrasive return chambers. The positioning protective sleeve locates the high-speed rotating blade component in the shot blasting chamber through the return chamber. Above the abrasive return chamber, there is an abrasive guide structure, which effectively reduces the wear of the positioning protective sleeve on the abrasive return chamber due to the existence of the abrasive guide structure. The part of the positioning protective cover that is severely worn is near the rotating blade assembly, and this part of the positioning protective cover cannot be equipped with any protective structure in the shot blasting chamber, so it is continuously eroded by abrasive, resulting in severe wear.
2. Solution measures
1) Reasonably select bearing models
Firstly, a detailed analysis of the working nature and operating conditions of the shot blasting machine is conducted. Due to the above characteristics of the self-aligning ball bearing, it basically meets the usage conditions. In terms of economic benefits, although self-aligning ball bearings have higher costs than deep groove ball bearings, they have increased their service life by tens of times and reduced maintenance and material costs.
2) Improvement of shot blasting machine box and bearing seat structure
A bearing seat installation positioning stop structure has been added to the shot blasting machine box, and an installation positioning protrusion has been added to the bearing seat to ensure the installation accuracy of the bearing seat. This avoids the problem of different installation accuracy caused by the actual operating ability of assembly personnel, and also avoids the problem of changing the original position accuracy of the bearing seat due to loosening of some bolts caused by vibration and other reasons.
3) Optimize the structural form of the positioning protective cover
Based on the analysis of the causes of severe wear and tear on the positioning protective cover, the original integral positioning protective cover structure has been changed to a two-stage split positioning protective cover structure. On the premise of not affecting the overall structural performance and use, increase the wall thickness of a positioning protective sleeve near the rotating blade component, and use medium carbon steel quenching treatment to improve its wear resistance. The other section is still made of seamless steel pipe, with the inner and outer diameters remaining unchanged, but the length is correspondingly shortened. This structural form of positioning protective cover has low cost, which can meet the design purpose and greatly extend the service time, reducing maintenance and material costs.
After improving the shot blasting equipment, a significant amount of downtime and maintenance costs have been saved, reducing the workload of maintenance personnel and ensuring the normal operation of the shot blasting machine. This has provided reliable equipment support for the factory to undertake more anti-corrosion construction tasks, enhanced market competitiveness, and improved economic benefits. At the same time, the company's professional technical level has also been improved, accumulating valuable experience for future equipment design and production.
