Troubleshooting of Ingersoll Rand 750 Air Compressor

An Ingersoll Rand XHP750 air compressor has frequently malfunctioned after more than ten years of use, mainly due to excessive consumption of compressor oil.

The main reasons for the increased consumption of compressor oil are the excessively high oil level in the oil-gas separator of the compressor, the rupture of the oil-gas separation filter element, and the blockage of the return oil pipeline. After checking and replacing the oil-gas separation filter element and the minimum pressure valve in sequence, none of them worked. Then, the return oil pipeline was inspected and no problems were found either. However, when the return oil small joint was found, it was discovered that the small joint hole was blocked, causing the oil level in the oil-gas separator to keep rising, resulting in the inability to separate oil and gas and increasing the oil consumption of the machine. After clearing the small joint hole, it was normal during the test run.

Overheating of the compressor and low exhaust pressure will also increase oil consumption. The main reasons for overheating are faults in the cooling system, such as low oil level, deteriorated oil quality, failure of the temperature control valve, dirty oil cooler or poor flow, deformation of the cooling fan or insufficient tension of the belt, etc. The main reasons for low exhaust pressure are insufficient engine power, dirty fuel and air filters, and loss of control of the airway regulation system.

In practice, all the possible faulty parts mentioned above were inspected one by one, but the compressor was still at a high temperature. Later, the temperature of the compressor body was measured on site. It was found that the temperature of the compressor rose to 110℃ within less than 10 minutes of operation. It can be seen that the cause of the high temperature is that there is a fault inside the compressor. When disassembling the machine, it was found that the bearing clearance was too large, causing axial movement and radial displacement of the male and female rotors. Axial movement led to friction between the male and female rotors and the end cover, while radial displacement caused friction between the male and female rotors and the stator. If any of these frictions occurred, the temperature would rise sharply. Fortunately, it was discovered in time and no major strain was caused, but it led to an increase in engine load and internal leakage in the compressor, which reduced the exhaust pressure.

The treatment method is as follows: Grind the scratched areas on the end faces of the male and female rotors, the cylinder body and the end cover, then replace the bearings, adjust the end face clearance to 0.1mm, and everything returns to normal during the test run.