[Mechanical Equipment Technology Edition] Daily Question 20180109: Common Faults in Refrigeration Systems (5.1)
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This post was last edited by YORK Industrial Refrigeration on 2018-1-11 at 10:59. Starting from now, in order to enhance communication among users, a \"Question of the Day\" campaign has been launched on the Mechanical Equipment Technology forum. We hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth points for active participation, 10-15 wealth points for correct answers. This question is valid for two days; no score will be given after that period. When a screw refrigeration compressor operates for a long time, the system functions stably, but the compressor makes loud noise and the screws wear out – what are the common causes of this? Answer: Bearing wear 3.jpg (326.59 KB, Downloads: 0) Download attachment Save to album Uploaded 3 days ago ============================== Quality promotions: Mechanical equipment---Maintenance procedures for York screw compressors https://bbs.hcbbs.com/thread-1806833-1-1.html Mechanical equipment---Upgrade of York Quinton control centers https://bbs.hcbbs.com/thread-1804837-1-1.html Mechanical equipment---Major repairs for GEA Grasox screw compressors https://bbs.hcbbs.com/thread-1800467-1-1.html Mechanical equipment---Disassembly and maintenance of British HOWDEN screw compressors https://bbs.hcbbs.com/thread-1832529-1-1.html Mechanical equipment---Disassembly and maintenance of Japanese Maekawa MYCOM screw compressors https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=
a. Debris is present in the rotor tooth grooves； b. Thrust bearing damage ； c. Wear of the main bearings, friction between the rotor and the casing ； d. Spool deflection ； e. Looseness at the joints of moving parts.
The premise of this problem is: with prolonged operation, the system runs stably, noise increases, and the rotor wears out. First, check and confirm whether there is an increase in noise from auxiliary components such as motors and fans, and address any issues found. Check for leaks in the system’s air and oil circuits that may cause increased noise, and address them. System-related reasons: 1. Insufficient refrigerant: Since screw refrigeration units rely on the pressure difference between suction and discharge to drive the movement of oil, a lack of refrigerant results in too low a pressure difference within the refrigeration system as well as too low a liquid level in the evaporator system. This makes it difficult for oil to return to the system, which can lead to dry friction in moving parts such as the rotors. As a result, the system generates more noise and the rotors suffer from wear. However, this cause would also lead to increased vibration. The problem states that operation has been stable (which indicates no severe vibration or insufficient refrigerant), so this possibility can be basically ruled out. 2. Abnormal differences in the high and low pressures of the refrigeration system, such as too low exhaust pressure and low oil pressure, can lead to increased bearing temperatures, greater wear, and increased noise. 3. A clogged oil filter or poor oil quality can lead to an increase in oil pressure difference. Other issues such as faults with the solenoid valves in the main oil circuit can also cause increased noise and abnormal sounds, while simultaneously accelerating wear on the moving parts. Mechanical causes: 1. Foreign objects in the mating areas between the rotors (caused by dirty oil, etc.), which lead to rotor wear and increased noise. 2. Wear or damage to the bearings (main bearings or thrust bearings) leads to rotor wear (including between rotors and between the rotor and the housing), resulting in increased noise. 3. The slide valve is in the wrong position or is deformed, resulting in wear and increased noise. 4. Loosening and other issues at other connection points lead to wear and increased noise. These are the considerations for now; new reasons will be added if they arise.
Check the key operating parameters of the refrigeration system; if any abnormalities are detected, adjust the amount of refrigerant, the amount of lubricating oil used, or the initial superheat value of the expansion valve as appropriate.
a. Debris is present in the rotor tooth grooves； b. Thrust bearing damage ； c. Wear of the main bearings, friction between the rotor and the casing ； d. Spool deflection ； e. Looseness at the joints of moving parts.
a. Debris is present in the rotor tooth grooves； b. Thrust bearing damage ； c. Wear of the main bearings, friction between the rotor and the casing ； d. Spool deflection ； e. Looseness at the joints of moving parts.
Lack of lubrication, dirty lubricant, oil supply interruption,
1. Insufficient lubricating oil or presence of impurities. 2. Insufficient concentricity with the motor. 3. The gap is not appropriate.
a. Debris is present in the rotor tooth grooves； b. Thrust bearing damage ； c. Wear of the main bearings, friction between the rotor and the casing ； d. Spool deflection ； e. Looseness at the joints of moving parts.
It is caused by poor oil return, air in the system pipes, and an excessive amount of refrigerant. When a screw compressor experiences vibration or abnormal noise, it is usually due to a lack of oil in the compressor or backflow of liquid into the compressor.
It is caused by poor oil return, air in the system pipes, and an excessive amount of refrigerant. When a screw compressor experiences vibration or abnormal noise, it is usually due to a lack of oil in the compressor or backflow of liquid into the compressor. First, the key operational parameters of the refrigeration system should be checked; if any abnormalities are detected, the amount of refrigerant, the amount of lubricating oil in the system, or the initial superheat value of the expansion valve should be adjusted accordingly. For screw compressors, this situation is extremely dangerous and can easily lead to complete damage of the compressor.