Number of views: 0 Author: AERTERANS Release time: 2024-09-07 Source: AERTERANS
1. Compressor maintenance case analysis
Recently, a customer sent a screw compressor to the factory for maintenance. The customer reported that the machine had a problem of low oil pressure and shut down, and then the equipment became stuck. After disassembly and inspection by the maintenance department, it was found that the radial and axial bearings at the exhaust end of the male rotor were damaged due to lack of oil, and the oil holes in the oil injection plate were also blocked. It was analyzed that the direct cause of bearing damage was that the customer failed to replace the old oil filter in time during use, causing the remaining impurities inside the oil filter to enter the oil system as the equipment was running. Since the injection plate is located at the end of the oil system and the diameter of the injection hole is small, these impurities can easily block the injection hole, causing a series of failures.
Problem analysis:
After the equipment was disassembled, the technical department analyzed the oil filter problem
1. Regarding the filtration accuracy of the oil filter. We learned from the user that the filtration precision of the oil filter purchased by the user is 25 μm, which far exceeds the 7-8 μm (maximum 10 μm) required by the original design of the equipment. Due to the low filtration accuracy, impurities can enter the oil system and block the oil holes of the injection plate, eventually causing oil shortage damage to the exhaust end bearing of the male rotor and equipment jamming.
Design requirements:
(1) The filter must be changed every time the oil is changed
(2) The filter accuracy level is 10μm
(3) Under clean conditions, the pressure loss is 0.2bar, and the maximum pressure loss cannot exceed 2bar.
(4) The machine stops when the oil pressure is 1.8bar. When driven by the inverter, the oil pressure is 0.5bar. The oil pressure switch is transferred to another protective oil pressure switch set to 0.5bar to stop the machine.
(5) When disassembling, use a belt disassembly device to disassemble
(6) Before installing the new filter, apply some grease on the sealing ring, and then screw it on
2. Filter material. The user originally used ordinary fiberglass paper, but this material may be at risk of damage during later use. In order to improve this problem, the design put forward new requirements: using a material combination of high-precision fiberglass paper and metal mesh. High-precision glass fiber paper can ensure the accuracy of filtration, while the role of the metal mesh is to prevent the fiber paper structure from being damaged, thereby improving the durability and stability of the overall material.
Customer independent procurement:
Design requirements:
3. Relief valve. The user purchased an oil filter with a relief valve. The pressure setting of the oil filter's relief valve was small, resulting in bypass operation at a lower pressure. Opening the relief valve increases the risk of impurities entering the oil system, which may adversely affect the stability and safety of the equipment. Therefore, the design selection requires that the oil filter does not have a relief valve to avoid potential risks.
2. Analyze the use of the overflow bypass valve in the oil filter through product testing.
Based on the above operating conditions, will the relief valve open the moment the equipment is just turned on or is there a risk?
1. If the filter element is clean + the lubricating oil meets the requirements + the filter element resistance is less than 2.5bar and the relief valve is not opened → the equipment operates without risk;
