Final answer:
Piston rings are used in small reciprocating compressors to prevent blow-by by sealing the gap between the piston and the cylinder wall, thereby maintaining compression efficiency.
Step-by-step explanation:
In small reciprocating compressors, such as those with pistons less than 2 inches in diameter, piston rings are typically used to prevent blow-by in the cylinders. These rings provide a seal between the piston and the cylinder wall to keep the compressed air or gas from leaking past the piston during the compression stroke.
The effectiveness of such seals is crucial for maintaining compression efficiency and ensuring the proper operation of the compressor. Engineering principles, such as those involving thermal dynamics and fluid mechanics, play an important role in understanding and solving issues related to blow-by in compressor cylinders.