In a two-drum watertube boiler, what is the upper drum called?

In a two-drum watertube boiler, the upper drum is referred to as the steam drum. This component is crucial in the operation of the boiler, as it serves multiple key functions. Primarily, the steam drum collects steam produced from the heated water as it rises from the lower drum. By providing a separation point, it allows steam to leave the system for use in turbines or heating applications while preventing water from entering the steam lines, ensuring that only dry steam is delivered.

Moreover, the steam drum also contributes to the overall water level management within the boiler system. It contains mechanisms for proper water circulation and can also house various fittings, such as safety valves and steam outlets. The proper functioning of the steam drum is essential for maintaining the efficiency and safety of the boiler operation.

The other types of drums mentioned, while they serve important roles in different boiler configurations, do not represent the upper drum in a two-drum watertube boiler. Understanding the distinct functions of the steam drum helps in comprehending the operational principles of watertube boilers and their designs.