When is a check valve closed in a hydraulic system?

A check valve in a hydraulic system is designed to allow fluid to flow in one direction while preventing backflow. The correct response indicates that a check valve is closed when the ball is pressed against a V-shaped seat. This design utilizes a ball that moves in response to fluid pressure; when the fluid flows in the intended direction, the ball is pushed away from the seat, allowing flow. If there is a reverse flow or if the pressure drops below a certain level, the ball is forced back against the V-shaped seat, effectively sealing the valve and preventing any fluid from flowing backwards.

Understanding this mechanism is crucial because it highlights the function of check valves in maintaining the correct flow direction and ensuring system integrity by preventing backflow, which could lead to pressure drops and inefficiency in hydraulic systems.