Importance

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Abstract

A vortex flow meter includes a bluff body which sheds a vortex train when a fluid flowing in a conduit moves therepast, the vortex train developing a delicate pressure variation in proportion to a flow rate of the fluid. The flow meter detects the flow rate by sensing the pressure variation and then converting it into an electric signal by means of a piezoelectric element or the like. A pressure sensor is detachably mounted in a pressure sensing chamber, which is defined in an internal space of the bluff body, and comprises a pressure receiving plate displaceable in response to the pressure variation, a sensor member such as a piezoelectric element for converting the displacement into an electric signal. The pressure receiving plate is arranged such that major part thereof is located in the conduit, while major part of the sensor member is located in a wall of the conduit and the outside thereof. The side surfaces of the pressure receiving plate are oriented parallel to or perpendicular to a direction of flow of the fluid. A drain port is located below a pressure induction port which is formed in a bottom portion of the pressure sensing chamber, so that part of the fluid entering the pressure sensing chamber is discharged through the drain port. The bottom wall of the pressure sensing chamber is inclined radially outwardly or formed with an upright wall. A flange for mounting the pressure sensor on the outer wall of the conduit and a cylindrical member for accommodating the sensor member are formed independently of each other and then welded together by an electron beam or the like. A support wall for fixing the cylindrical member extends from the flange. A second sensor member identical in construction with the first is employed to compensate for externally derived vibrations which may act on the pressure sensor. Leads extending out from the pressure sensor have a small rigidity.

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First Claim