Which type of valve is commonly used to isolate equipment in a steam system?

A gate valve is specifically designed to effectively isolate equipment in a steam system. Its construction allows for a straight flow of fluid with minimal resistance when fully open, thus ensuring that there is minimal pressure drop across the valve and optimizing system efficiency. When closed, a gate valve provides a tight seal that prevents any flow, offering complete isolation. This aspect is particularly critical in high-pressure steam systems, where maintaining the integrity of the system is essential for safety and operational efficiency.

In contrast, while other valves serve important functions within a steam system, they do not offer the same isolation capability. For instance, a check valve primarily prevents backflow rather than isolating equipment. A butterfly valve provides quick shutoff and is used in applications where flow control is needed, but it generally does not provide the tight seal necessary for complete equipment isolation. A pressure relief valve, on the other hand, is designed to relieve excess pressure for safety purposes and is not intended for isolation at all. Thus, the gate valve stands out as the most suitable choice for isolating equipment in a steam system.