What device in hydraulic systems allows normal fluid flow but closes if the flow exceeds a certain rate?

In hydraulic systems, the device that allows normal fluid flow but closes if the flow exceeds a certain rate is known as a hydraulic fuse. Its primary role is to enhance safety within the hydraulic system by preventing excessive fluid flow that could damage components or create unsafe conditions.

When fluid flows normally, the hydraulic fuse remains open, facilitating standard operation. However, if the flow rate surpasses predetermined limits—often due to a hose failure or unexpected system behavior—the hydraulic fuse will activate and effectively shut off the flow. This action helps protect the system from potential damage and ensures that it operates within safe parameters.

The other devices mentioned have different functions and do not specifically provide the flow-sensitive shutoff characteristic that a hydraulic fuse does. For instance, a pressure regulator manages system pressure but does not address flow rate directly. A flow restrictor limits the flow but does not automatically close in response to an excessive flow situation. A pressure switch activates at specific pressure levels but again does not directly relate to flow rate management. Thus, the hydraulic fuse stands out as the correct choice for this question regarding flow management in hydraulic systems.