Smoke comes from the inlet filter when the air compressor is shut down
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One of our company’s OGD--40.2\7 air compressors manufactured by Zhengli was producing a large amount of blue smoke from its inlet filter when it was shut down normally. Which components are likely to be at fault in such a situation?
Your machine is a screw compressor, right? When a screw compressor exhibits such issues, the oil separator and filter should be checked; problems with solenoid valves are generally not the cause.
I’ve never seen such a problem; I guess compressed air flowed back into the intake port when the machine was shut down, and because the temperature of that compressed air was very high, it caused the filter to smoke. If it occurs only occasionally, then the intake and exhaust systems should be checked; if this situation persists over time, considering installing a check valve might be a good option.
The blue smoke may be caused by the breakdown of lubricant. Is the oil temperature high? Excessively high temperatures can also cause the lubricating oil to undergo thermal decomposition under the catalysis of metals, resulting in the formation of free carbon, acids, and moisture (carbon deposition) that are harmful to operation; in severe cases, this can lead to the screw getting stuck.
85 degrees is not low, but it’s not yet at a level that causes smoking. The oil temperature sensor at 85 degrees Celsius is located at the oil separator; it is likely that the temperature at the inlet filter when smoking occurs is higher than 85 degrees. The smell of lubricant burning and smoking is different from that of other substances, so it should be easy to tell at the scene.
It’s probably oil mist. When the compressor stops, if the inlet check valve doesn’t close quickly enough, the high-pressure gas inside flows back, which results in the backflow of gas containing oil, similar to smoking
Reply to 7# wmx007: The poster is correct. When the “Stop” button is pressed, the intake valve closes first, and then the main unit shuts down after a few seconds while in no-load mode; in this case, there is no issue with smoking. However, if the intake valve gets stuck or the electronic control system fails, smoking will occur during shutdown. Additionally, using the “Emergency Stop” button to shut down the device also results in smoking.
It could be a leak in the check valve or load valve; the shutdown was caused by high-temperature, high-pressure gas flowing back, which carried away some of the lubricating oil in the engine head and resulted in smoke and fumes. The air filter may have been damaged.
The decomposition of oil mist or lubricant that is carried back can be examined by checking its smell and by using a substance to determine the nature of the deposits. The smell of oil decomposition is quite different; if there is no smell, check the viscosity of the deposits
This post was last edited by bakleilei on 2011-5-14 at 12:49. I also have such a screw compressor here, and I’m studying it. Personally, I think it is the delay in closing of the solenoid valve that causes a delayed closure of the air intake valve. I would appreciate it if someone could point out the underlying reasons. ————————————————Divider line—————————————————————— Correction to the error above: The unit I have here has now been repaired; it’s not a problem with the solenoid valve – the issue lies in dirt on the air intake valve (carbon buildup or other small particles, very fine things). ）It’s stuck.