What type of valve is commonly used to control flow in a steam boiler?

A globe valve is commonly used to control flow in a steam boiler because it is specifically designed to provide precise flow regulation and throttling capability. The globe valve has a spherical body and a movable disc or plug that can be raised or lowered to open or close the flow path. This design allows for better control over the flow rate compared to other types of valves.

In steam applications, where maintaining specific pressure and temperature conditions is crucial, the ability to finely adjust the flow makes globe valves particularly advantageous. They can effectively manage the flow of steam and maintain the desired operating conditions within the boiler system.

Ball valves, while excellent for on-off control, are not ideal for flow regulation due to their design, which does not allow for gradual adjustments. Butterfly valves provide quick shut-off but may not offer the same level of precision in controlling flow. Check valves are used primarily to prevent backflow and are not suitable for regulating flow.