What type of valve is always open or always closed, and does not regulate fluid flow?

The gate valve is designed specifically to be either fully open or fully closed, making it an excellent choice for applications where the flow of fluid needs to be completely stopped or allowed unrestricted passage. This type of valve operates like a gate, opening and closing without regulating the flow; it simply allows or blocks fluid passage. When the gate is in the open position, there is minimal pressure loss through the valve, which is beneficial in systems where a straight flow path is desired.

In contrast, other valves such as the ball valve, butterfly valve, and check valve serve different functions. A ball valve can also be fully open or closed but is primarily used for quick shut-off and can regulate flow at a more significant degree compared to a gate valve. The butterfly valve operates using a disc to control flow and can adjust the flow rate more finely, while the check valve is designed to allow fluid to flow in one direction only, preventing backflow. These operational characteristics clearly differentiate the gate valve's specific functioning as being solely for on/off control, without flow regulation.