Which of the following compressors does not require lubrication?

The rotary lobe type compressor is designed with lobes that rotate without making direct contact with each other, which eliminates the need for lubrication. This design minimizes wear and maximizes efficiency since the lobes move through a specially designed casing without requiring oil for lubrication. The operation relies on the movement of air and the specifics of its mechanical configuration, allowing it to work efficiently without the lubrication that many other types would need.

In contrast, the reciprocating type, scroll type, and screw type compressors typically require some form of lubrication to ensure smooth operation and reduce friction. These systems depend on moving parts that interact more closely, which can lead to wear and tear without the protective layer that lubrication provides. Therefore, the rotary lobe type stands out as the only option that does not necessitate lubrication for its operation.