VORTEX FLOWMETER

PURPOSE:To intercept the ultrasonic waves propagating through a vortex generation body in a vortex flowmeter. CONSTITUTION:Columnar members 22 and 23 having paths 30 and 31 are mounted on a housing body 20 to form a vortex generation body 21 in a passage 20a and a measuring path 29 is formed with the paths 30 and 31 communicating with each other. A slight clearance C1 is provided between the columnar members 22 and 23, an ultrasonic transmitter 35 and an ultrasonic receiver 36 are mounted on the columnar members 22 and 23 and an amplifier circuit 37 is connected thereto. When a fluid in the passage 20a flows to generate a Karman's vortex at a downstream point of the vortex generation body 21, a pressure difference is caused between introduction holes 32 and 33 so that a flow is generated in a measuring path 29 at a cycle the same as that of a Karman's vortex. An ultrasonic signal transmitted with the ultrasonic wave transmitter 35 is modulated by the flow and received with an ultrasonic transmitter 36. The modulation of the ultrasonic signal is demodulated with the amplifier circuit 37 to compute a flow rate of the fluid. The noise propagated to the columnar member 22 from the ultrasonic transmitter 35 is intercepted by the gap C1 and none transmitted to the columnar member 23 thereby improving the S/N ratio of the received signal of the ultrasonic receiver 36.