Which phrase helps a fitter remember the associated valve type for a check valve?

The phrase "Swing the gate open" is particularly effective for remembering the associated valve type for a check valve because it evokes the image of a pivoting mechanism, similar to how a swing gate operates. Check valves function to allow fluid flow in one direction while preventing backflow, which can be likened to the action of swinging a gate to open or close access. Just as a gate swings to allow entry in one direction while blocking it from the opposite side, a check valve ensures that fluid moves through it without reversing direction. This conceptual link between the physical action described in the phrase and the operational principle of a check valve aids in recalling its function more clearly.

The other phrases do not accurately reflect the mechanism of a check valve and may lead to confusion with other types of valves, such as gate valves which do have a gate-like opening, but are not designed for the same purpose as a check valve.