New Mexico Pipe Fitter Journeyman (JPF) Practice Exam

The type of valve that does not allow for regulation effectively is the gate valve. Gate valves are designed to either fully open or fully close a flow path. When in the open position, they provide little resistance, allowing for smooth flow. This characteristic makes them ideal for applications requiring a straight-line flow of fluid without pressure drop. However, because gate valves do not have an adjustable flow feature, they do not allow for fine-tuning or regulation of flow (i.e., they cannot be partially opened to achieve a specific flow rate). In contrast, butterfly, globe, and ball valves are all capable of regulating flow. Butterfly valves allow for control by adjusting the position of a disc within the flow path. Globe valves are specifically designed to provide effective flow control by using a movable plug to choke flow, enabling variable flow rates. Ball valves can also be adjusted to manage flow, though they typically provide a more straightforward on/off function than globe valves. Thus, the gate valve's function as a simple on/off type makes it the correct choice for the question regarding regulation capabilities.