What type of regulators are found on package fire-tube or watertube boilers where feedwater pumps operate?

The correct choice, which identifies the type of regulator found on package fire-tube or watertube boilers where feedwater pumps operate, is float regulators. Float regulators are designed to maintain a specific water level within the boiler. They accomplish this through a float mechanism that rises and falls with the water level, opening or closing the feedwater supply to maintain the desired level.

In a boiler system, maintaining the correct water level is crucial for safe and efficient operation. If the water level is too low, it can lead to overheating and potential damage to the boiler. Conversely, if it is too high, it can cause water carryover into the steam system, which can also lead to operational issues. The float mechanism provides a reliable means of controlling this water level automatically, making it well-suited for use in package fire-tube and watertube boilers.

Other options, such as pressure regulators, might be more involved in controlling pressure within the system but are not directly responsible for managing feedwater levels. Pneumatic regulators typically serve different functions involving air pressure systems, and diaphragm regulators have specific applications unrelated to the management of water levels in a boiler context. Thus, the float type is specifically designed for maintaining feedwater levels, which is why it is the