Compressor rooms are usually dirty, dusty places that take care and attention to keep clean. It’s not that the compressor operators are slobs, it’s that the air compressors must suck in surrounding air to work and to keep cool. This creates a negative pressure around the compressors that draws in anything airborne.
The photograph shows a compressor with a lint problem. The oil cooler and after cooler of this air-cooled lubricated screw compressor were clogged, reducing the needed cooling air flow to abnormal levels. This unit was running hot, and its discharge air temperature was excessive. Overheating a compressor causes varnish to form on internal cooling surfaces, making the overheating problem permanent. With excessive varnish, even with clean coolers, the compressor will run warmer than normal.
The high compressed air discharge temperatures that accompany overheating cause other problems. Hot compressed air contains more moisture than normal, with the amount of entrained water vapor doubling with each 20 degree F (11 C) increase in temperature. This wet airstream will overload air dryers and cause water to form in the downstream distribution pipes. The water, mixed with dust, lubricant and pipe scale can foul anything it touches, and even present an environment where microbes can grow. Indeed, this was what was happening with the compressor in the photograph which was located in a food products plant.
Some tips:
• Always ensure the cooling surfaces are free of dust and debris,
• Ensure your compressor room intake air is as clean and cool as possible (but not below freezing),
• If clogging of cooling surfaces is a constant problem, then filter your intake air,
• Regularly maintain your filters to ensure effectiveness,
• In extreme environments filters will need to be applied on each individual compressor, and the compressor room cooling air intake. Multi-stage filters are sometimes required,
• Ensure filters are large enough not to create a restriction to flow.
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