Abstract: A fluid flowmeter includes a bluff body for producing vortex shedding free of intermittency. The body has at one end a support member for mounting in a conduit and has proximate its downstream surfaces a pair of orifices. A vibratory planar sensor, preferably ferromagnetic, is situated in a sensor chamber within the support member for vibrating in response to received pressure fluctuations. A magnetic detector is situated in proximity to the sensor for producing an electrical signal when the sensor vibrates in response to vortex shedding. Fluid in the conduit, and thus vortex shedding, is coupled from the orifices through a pair of parallel channels, which are in non-fluid-flow communication with one another, to opposite sides of the sensor. In one embodiment, the sensor comprises a diaphragm rigidly mounted along its periphery whereas in another embodiment the sensor comprises a rigid, substantially planar disc vibratorily mounted along its periphery.

Abstract: Described are several signal processors for measuring the flow rate of fluid. These processors incorporate various combinations of a unique tuneable bandpass filter, which rely on variable rate integration, and unique trigger circuits which trigger on the change of signal slope. Also described are a spectrum analyzer and oscillators which employ the tuneable bandpass filter.

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.

Abstract: A bluff body flowmeter, including a bluff body having a planar base surface portion disposed normal to fluid flow and a pair of converging downstream surfaces, is provided with a fluid flow channel in the base surface portion, a sensor in the channel and a shield which partially covers the channel and protects the sensor from impact damage. The shield and channel are mutually adapted so that fluid flow through the channel is substantially unidirectional. In one embodiment at least that portion of the shield which covers the channel is shorter than the channel thus forming a rectangular notch which acts as a fluid flow entrance port.

Abstract: Flowmeters utilizing nonstreamlined, bluff bodies and sensors are disclosed for generating oscillating wakes in a fluid flowing through a pipe to produce high signal-to-noise signals which are free from intermittency and are sensed outside of the wake in the flow near and upstream from the bodies. Each of the bodies comprises prescribed geometric configurations and includes a base surface facing the flow and downstream surfaces to control the oscillatory flow. The bodies each have sharp upper and lower corners at the edges of the facing base surface for defining separation lines for the flow. The facing base surfaces are selectively blunt or convex for reducing pressure loss in the pipe due to the bluff body.