There are convex points arranged on the surface of the guide plate in a certain way, so that the treatment liquid can form turbulence, increase the transmission rate and self-cleaning function. The guide plate clamp the diaphragm in the middle, but not the pressure of the diaphragm, so that the treatment liquid quickly flows through the surface of the diaphragm, through the liquid in the middle of the diaphragm along the filament-like support flow to the periphery of the central pull rod, with the help of the guide plate O-type rubber ring and treatment liquid isolation and flow to different outlets.