Which type of valve is considered unsuitable for throttling flow?

The gate valve is considered unsuitable for throttling flow due to its design and functionality. This type of valve is primarily intended for fully open or fully closed positions, making it efficient for starting or stopping flow rather than regulating it. When a gate valve is partially opened, the flow tends to create turbulence and may cause damage to the valve or the piping system over time. This is because the gate does not offer the necessary resistance and control over the fluid dynamics as it is designed to create a straight-line flow with minimal obstruction.

In contrast, globe valves and ball valves are better suited for throttling as they can be adjusted to various degrees of opening, allowing for finer control of flow rates. Check valves, on the other hand, are designed to prevent backflow and are not used for throttling at all. Therefore, gate valves should not be used in applications where flow regulation is required.