Elijah McCoy was granted U.S. Patent 320,379 for a “Lubricator” on June 16, 1885. This invention was an improvement on a previous lubricator he had patented with Clarence B. Hodges. The core problem this new patent addressed was that “prime water” (water from a boiling boiler that gets mixed with steam) would often fill up the lubricator’s equalizing pipe. This water column would neutralize the pressure needed to drive oil, causing the lubricator to stop working.
McCoy’s solution was a simple yet brilliant design change:
- Elongated Neck: The lubricator’s condenser was given an elongated neck that rose significantly above the point where the steam pipe from the boiler was attached.
- Raised Equalizing Pipe: The equalizing pipe was extended to run nearly to the top of this new, taller neck, well above the steam inlet.
This design ensured that any water from the boiler would simply flow back out of the steam pipe before it could reach the top of the equalizing pipe. This prevented the water column from forming, guaranteeing a constant and reliable flow of steam down the equalizing pipe and a consistent lubrication feed.
Societal Impact and Legacy
This patent is a perfect example of McCoy’s genius. He didn’t just invent; he continually refined his products to solve the practical problems that arose from their use in the real world.
- Enhanced Reliability: By addressing the issue of prime water, McCoy made his lubricators even more reliable. This was a critical factor for the safety and efficiency of industrial machinery, as a lubricator that failed to feed oil could lead to catastrophic engine failure.
- Industrial Innovation: This patent demonstrates McCoy’s deep understanding of the physics of steam engines and his ability to apply that knowledge to create a superior product. His continuous improvements to his lubricator designs were a major factor in the widespread adoption of his inventions.
- The “Real McCoy”: As with his other patents, this lubricator’s superior reliability was far better than the numerous imitations on the market. It is part of the story of the origin of the phrase “The Real McCoy”, which is widely believed to have originated from engineers who insisted on his authentic products.
- The Inventor’s Legacy: Elijah McCoy was a brilliant African American inventor who, despite immense racial discrimination, became a foundational figure in American industrial technology. His numerous patents were critical to the development of the railroad system and factory machinery.
