YZF-L4 pressure actuated valve is a signaling device that converts pressure differential signals into electrical signals through mechanical transmission. It is used in electrically controlled, terminal-type centralized dry oil lubrication systems, installed at the ends of two supply main pipelines. When the pressure at the end of the main pipeline exceeds the valve's set pressure during supply, the valve activates and sends a signal to the electric control cabinet. An electromagnetic directional valve is used to alternate the supply of the two main pipelines. The valve sends signals accurately and reliably, and the set pressure is adjustable.