Causes and solutions for oil leakage of centrifugal fan bearing housing

Causes and solutions for oil leakage of centrifugal fan bearing housing

In the application process, the shaft seal of the fan impeller side bearing bush has always suffered serious oil leakage, which not only causes serious waste of lubricating oil but also pollutes the equipment and the ground; the blower bearing is often in low oil level operation, threatening the safe operation of the blower; Replenishment of oil has increased the workload of the operators. In order to solve the oil spill problem, the technicians came up with a variety of methods, but they did not achieve the desired results. Many improvements and tests have found the main cause of oil leakage: First, when the blower is running, the impeller side bearing seat and the impeller are positive pressure zones, and the wind will blow into the bearing chamber from the gap between the casing and the outer sleeve. Secondly, there is a design defect in the bushing between the impeller side bearing housing and the impeller, and the loosening phenomenon occurs in the long-term operation. The collision and friction between the bushing and the shaft cause the clearance to be too large, and the wind enters the bearing chamber from this gap. Bring the oil out and increase the amount of leakage. After finding the source of the leak, the problem of oil leakage is completely solved by the process of externally adding a guide ring inside the bearing sleeve.

Cause analysis and solution

In order to solve the problem of oil leakage in the bearing housing of the blower, a vacuum device is installed to modify the oil leakage of the bearing housing. The negative pressure oil pumping device sucks the oil into the inlet duct of the blower. Although it solves the problem of oil leakage and contamination of the blower bearing seat and the ground, the oil is pumped into the blower, and the lubricating oil is stored in the blower casing to cause the blower impeller to be polluted and lubricated. The amount of oil used increases and the oil is replenished more frequently. By improving the labyrinth seal, installing the exhaust cap, and installing the casing felt seal, etc., although certain effects have been achieved, the oil leakage problem has not been fundamentally solved.

After a long period of observation, it can be found that after the oil hole cover on the bearing seat is unscrewed, a strong air flow flows out from the bearing housing, and the air flow pressure is large, and the lubricating oil in the bearing seat flies out with a strong air flow, and the oil can is used. When the funnel) replenishes the oil into the bearing housing, the oil is blown into a parabolic shape by the airflow. According to the analysis, under normal conditions, the bearing rotates at high speed, and the wind is blown into the bearing chamber from the gap between the casing and the outer sleeve. Due to the obstruction of the bearing end cover and the labyrinth seal, the cavity is slightly positive pressure, and the strong air flow is generated by the blower. The high-pressure air inside is caused by the gap between the bushing and the impeller, the shaft and the inner ring of the bearing.

The sleeve axially positions the bearing inner ring and the fan impeller, and the sleeve and the shaft are in a clearance fit. After long time running, the sleeve is loosened. The tapping on the sleeve is fixed by the set screw. The effect is very good in a short time, but the sleeve will still loose after running for less than one month. The analysis believes that to solve the loosening, it is necessary to have a strong filling to the matching clearance. To solve the oil leakage, the hurricane problem of the blower to the bearing housing must be eliminated, and then the high-pressure injection is applied to the gap between the sleeve and the shaft to solve the shaft. The loose hurricane is set; the outer ring of the bushing and the guide ring are used to change the wind direction to eliminate bearing oil leakage.

During the minor repair in December 2006, four Φ7 through holes were evenly drilled along the circumference in the middle of the length direction of the No. 1 furnace, and then the M10 thread was tapped. The high-pressure injection gun is used to align the rubber into the gap between the sleeve and the shaft in three times. The purpose of the three-dimensional symmetric injection is to prevent the sleeve from being skewed and the sleeve and the bearing and the blower casing are caused. Friction, welding the guide ring on the sleeve 5 cm from the casing.

After the transformation, after more than one year of operation observation, the bearing seat did not leak oil, the sleeve was positioned well, and no looseness occurred. The transformation effectively eliminates the collision and friction between the bushing and the shaft and the fan impeller and the inner ring of the bearing, eliminates oil leakage, and the bearing works under normal lubrication conditions, effectively preventing bearing burnout and fire accidents, and ensuring the blower. The safe operation of the unit saves the lubricating oil, eliminates the vibration of the air passage, reduces the noise, reduces the working intensity of the operating personnel, improves the working environment, and has significant economic benefits and promotion value.