What is the resistance to flow provided by swing check valves?

Swing check valves are designed to allow fluid to flow in one direction while preventing backflow. When it comes to the resistance to flow they provide, these valves have a relatively low resistance compared to other types of check valves. This is primarily because they use a hinged disc that swings open with the flow of fluid and closes when the flow reverses.

Due to their design, swing check valves can minimize turbulence and pressure drop in the system, resulting in less restriction to the flow. Consequently, this leads to a designation of providing minimal resistance to flow. The design allows for efficient operation in applications where a low pressure drop is critical, such as in various piping systems.

Other options suggest varying degrees of resistance that do not align with the operational characteristics of swing check valves. Maximum or moderate resistance implies significant hindrance to flow, which is contrary to the primary function and advantages of using swing check valves. No resistance would suggest that the valve does not affect flow at all, which is also inaccurate since there is still some level of restriction due to the valve's presence in the pipeline, albeit minimal.