Water in a D rating feed water heater is prevented from entering the steam line by what mechanism?

The mechanism that prevents water from entering the steam line in a D rating feed water heater is a loop seal or internal overflow. This is designed to ensure that there is a barrier that keeps the water in the feed water heater separate from the steam in the steam line.

The loop seal creates a physical barrier that prevents backflow of water into the steam line, allowing steam to flow freely while maintaining the necessary pressure and temperature without risking water getting into areas where it could cause damage or inefficiencies. Internal overflow systems work similarly by providing a designed outlet for excess water, ensuring that the steam lines remain clear of liquid water.

Understanding this mechanism is crucial because improper management of water and steam could lead to detrimental conditions such as water hammer, reduced efficiency, or even equipment failure. This understanding will help in both operating as a stationary steam engineer and in troubleshooting potential issues within the system.