LUGB-type 2 vortex flow meter measuring in the flow of liquid of steam ,gas and low viscosity according to Carmen and Struhal relavant spiral produce and on the theory of the relationship .As show in picture ,In the meter body vertical insert a triangular prism root namely the happening of the body,when eddies of medium flow through the table body, in triangular prism behind the alternate produce in opposite directions regular karman swirl ,its spiral separation and the flow of the medium frequency F speed by head is proportional to the V detected the number of spiral ,can measure the flow velocity,again according to the table body mouth