Relationship between the cooling efficiency of the inter-stage cooler in air compressors and machine vibration
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One of our company’s air compressors, after operating for a year, experienced a sudden increase in vibration levels on the high-pressure side, reaching 70 um and triggering an alarm. Adjusting the oil temperature did not help improve the situation, but as the temperature dropped, the vibration levels decreased as well; when the water temperature was 20°C, the vibration levels fell to 63 um. It was observed that the outlet temperature of the first-stage cooler dropped from 40°C to 34°C. Therefore, it is suspected that there is a causal relationship between the vibrations on the high-pressure side and the cooling efficiency of the cooler. I’d like to ask an expert: is it like this? Why?
Where are the experts? ! Looking beyond the surface to understand the essence, what is really going on?
Lubricating oils should be sent to the manufacturer for physical and chemical analysis to determine their quality.
All the parameters of the lubricating oil are excellent, and the oil temperature is kept within the range of 34–35°C; as can be seen from the curve, it follows the fluctuations in water temperature
Has the owner changed the oil since it was put into use? At higher temperatures, the viscosity of the lubricating oil decreases, and it cannot be pumped up using the oil pump. Since the cylinders require high-pressure lubrication, this may be due to the inability of the lubricating oil to reach those areas, thus preventing proper lubrication. As the temperature decreases, the viscosity of the lubricating oil increases.
Lubrication can basically be ruled out; all parameters of the oil are within acceptable limits, and both the oil level and temperature are well controlled. The key is that the vibration value corresponds to changes in water temperature.
Our company has also encountered similar problems: in the secondary dual-cooler of the Shaanxi Blower air compressors, there was a six-degree difference in air temperature, and foreign objects were blocking the pipes; however, the bearings showed little change and were basically in normal condition.
Guess: At high temperatures and with high air humidity, more moisture is released when the gas is compressed. If this moisture is not removed in a timely manner, it may cause excessive vibration in the unit; it is necessary to check whether the drainage between stages is adequate
It’s okay; high vibration in the unit is closely related to whether the rotor is balanced. When the vibration level is not high, the compressor cleaning device can be used to remove the deposits on the impeller
When the cooling effect of the cooler is poor, the machine may experience surge; after surge occurs, the vibration level of the machine increases naturally. Check the records to see if there were any signs of surge, as well as the temperature at the inlet on the high-pressure side... Specific situations require specific analysis, as there are various factors that influence vibration levels