US 4,069,708 A · Flowmeter plate and sensing apparatus

Abstract

A bluff body flowmeter for a pipeline is disclosed with a plate mounted within the pipe and downstream of a vortex generating body for maintaining fluid vortex streets separated to facilitate their detection and translation into indications of flowrate through the pipe. The plate is mounted downstream of the vortex generating body at a prescribed distance which defines the vortex sensing site. A plurality of plate and sensing embodiments is disclosed. In one configuration, the plate is a flat rectangular plate spanning the entire inner diameter of the pipe and has its ends rigidly secured to the inner pipe wall. The plate comprises upper and lower surfaces having a downstream length for enabling fluid vortex signals to occur alternately about the environment of each such surface. The upper and lower plate surfaces flex, or move within a midsection between its fixed ends and that flexing causes vortex signal changes which are detected by a sensor. Other embodiments including cylindrical rods affixed to upper and lower plate surfaces; a free-to-move, rather than both fixed, plate ends; ferromagnetic spheres and movement confining block cavities; as well as, central and shuttle sensor-plate configurations which do not require flexure of the plate for flowmetering are also disclosed. A capacitance plate arrangement is also disclosed.

Claims30

Dependent claims

In combination,

means for generating staggered trails of vortices in a fluid flow streamwise in a conduit and
a thin plate mounted a prescribed distance downstream from said generating means for maintaining said staggered trails of vortices in separation and said plate having upper and lower surfaces defining a site in said conduit for sensing staggered and separated trails of said vortices,
said conduit comprising means defining an inner wall,
said generating means comprising a bluff body having a first surface including a prescribed height dimension and having second surfaces extending streamwise from said first surface toward said plate, and
said plate comprising a frontmost surface mounted downstream from said second surfaces at a distance substantially two to three times the height dimension of said first surface.

2 more elements

Apparatus for use in measuring the flowrate of fluid in a conduit with a bluff body having

a base surface disposed substantially normal to the streamwise direction of fluid flow, said surface extending along a diameter of said conduit and between the walls thereof,
a pair of downstream surfaces extending downstream from said base surface and meeting said base surface along a pair of edges,
said base and downstream surfaces being mutually adapted so that the boundary layers of said fluid separate from said body at said edges, and
the ratio of the axial length of said body to the height dimension of said base surface being between 1 and 2 and the ratio of the height dimension of said base surface to the inner diameter of said conduit transverse to the longitudinal axis thereof being between 0.15 and 0.4,
said apparatus comprising
a thin plate fixedly mounted entirely within said conduit and for stationary nonmovement in a streamwise direction and downstream from said downstream surfaces at a distance substantially two to three times the height dimension of said base surface, said plate having first and second surfaces for maintaining staggered trails of fluid flow vortices in separation in their flow downstream from said edges and past said plate surfaces and to define a site for sensing staggered and separated trails of said vortices.

3 more elements

Dependencies are inferred from the claim text.

Flowmeter plate and sensing apparatus

Life of this patent

Flowmeter plate and sensing apparatus

Life of this patent

Abstract

Claims30