KARMAN VORTEX FLOWMETER

PURPOSE:To obtain an accurate flow rate signal free from frequency loss by eliminating the strain of the Karman vortex in the post-stream of a Karman vortex detection part, by properly selecting the dimensional constitution of the signal detection part of the Karman vortex. CONSTITUTION:A columnar vortex generating body 3 generating a Karman vortex is arranged so as to traverse the flow passage of a housing 2 and a pressure introducing hole 24 or a resistance wire 30 is provided to the vortex generator 3 to form a Karman vortex detection part 10. The detection part 10 is provided at a position of l/h6 when the difference-in-level dimension of the inner surface 2a of the upper wall of the housing 2 and the corner part 8 of an engaging part 7 on the upstream side thereof is set to (h) (protrusion; +, depression; -) and the vertical distance from the corner part 8 on the upstream side to the upper end of the detection part is set to (l). This position is a region generating no frequency loss and the detection part 10 can accurately detect the generation frequency of the Karman vortex without receiving the effect of the trailing vortex generated from the difference in level of the engaging part of the vortex generator 3 and a flow rate can be measured with good accuracy.