A mechanical seal is a device used to prevent leakage of fluids (such as water, oil, or gas) between rotating and stationary parts in machinery. It is commonly found in pumps, compressors, mixers, and other rotating equipment. The seal works by using a combination of two flat, smooth surfaces—one fixed and one rotating—pressed together by spring force. This forms a tight barrier that helps contain the fluid within the system while minimizing friction and wear. Mechanical seals are critical for maintaining efficiency, preventing contamination, and ensuring safety in industrial applications.