High sensitivity vortex shedding flowmeter

摘要

The vortex shedding flowmeter comprises a vortex generating bluff body of an elongated shape disposed across a cross section of a flow passage, that includes a blunt leading edge and a planar trailing edge, which planar trailing edge has two sides shielded from the moving fluid by a planar shielding member enclosing at least two sides of the planar trailing edge wherein the two sides of the planar trailing edge are respectively exposed to the fluid pressure at the two sides of the bluff body by one or more pressure openings. The vortex generating bluff body is mechanically coupled to a transducer that converts the alternating lift forces on the bluff body exerted by the vortices shed from the two sides of the bluff body in an alternating pattern to electrical signals, wherein the alternating lift forces generating the electrical signals are amplified by the planar trailing edge of the bluff body as the two sides of the planar trailing edge are respectively exposed to the alternating fluctuations of the fluid pressure associated with the vortex shedding by the pressure openings open to specific locations in the two sides of the bluff body where the alternating fluctuations of the fluid pressure is mostly pronounced. The vortex shedding flowmeter of the present invention may further include a wing sensor disposed parallel to the bluff body across another cross section of the flow passage downstream of the bluff body, which wing sensor may be coupled to the same transducer coupled to the bluff body or another transducer wherein electrical signals from the two transducers are synthesized to exclude noises and extract the vortex signals at the maximum level.