The Foxboro Company

Gordon W Chitty

Yousif A Hussain

Wade M Mattar

Everett O Olsen

Duane T Thompson

Joseph P DeCarlo

James H Vignos

Richard W Kalinoski

Paul M Zavracky

Richard H Morrison, Jr

Anthony C Gilby

Vernon C Westcott

Christopher R Brown

John G Panagou

A rigid central manifold block defines a coaxial inlet and outlet of the flowmeter and supports at least one continuous conduit loop substantially encircling the block and having its inlet and outlet ends closely spaced and rigidly connected to the block. Preferably, the loop includes a straight section perpendicular to the inlet and outlet ends. Dual drive means are preferably provided for oscillating the straight section back and forth about its perpendicular bisector and complementary position detectors employed at or near the opposite ends of the straight section, preferably at the same location as the drive units, provide readouts which are combined algebraically and synchronously demodulated to yield a Coriolis-related output indicative of mass flow. Preferably, a second loop, identical and parallel to the first, is supported by the same block. The block is channeled to serve as a manifold and interchangeable manifolds are disclosed for series and parallel flow through the two loops, respectively. The plane of the loop or loops can be oriented perpendicular or parallel (in line) to the process line.

Coriolis-type mass flowmeter

A vortex sensor 14 measures a flow rate of a fluid flowing through a flow passage by detecting alternating pressure variations 26a and 28a generated by a shedding body 16 placed in the flow passage. The vortex sensor 14 includes a sensor housing 32 enclosing piezoelectric sensing elements 62, 64 which are acted on by a movable member 30. The lifetime of the sensing elements in the closed interior is enhanced by providing surface barriers, oxidizing exposed interior surfaces, or providing a gas reservoir. In applications where fluid leakage may be accepted, a controlled leak restrictor provides a limited rate diffusion path to the atmosphere allowing a minimum partial pressure of oxygen to be maintained.

Piezoelectric pressure sensor

A vortex sensor 14 for measuring a flow rate of a fluid flowing through a flow passage. The flow rate is measured by detecting alternating pressure variations 26a and 28a generated by a shredding body 16 placed in the flow passage. The vortex sensor 14 includes a sensor housing 32 having two cavities 44 and 46 interconnected by a channel 42. An Axle 52 of a spool member 34 is slideably disposed in the channel 42 and allows each of two flange members 54 and 56, connected proximate each end of the axle 52, to shuttle back and forth with respect to the sensor housing 32. A piezoelectric sensing element 62, 64 and a biasing mechanism 58, 60 are disposed between the flange members 54 and 56 and the sensor housing 32. The alternating pressure variations are applied to each flange member 54, 56 causing the spool member 34 to shuttle back and forth. When the spool 34 moves, mechanical forces are coupled to each sensing element 62 and 64 by biasing mechanisms 58 and 60. Circuitry 78, interconnected to the sensing elements 62 and 64, detects signals generated by the sensing elements as a result of forces applied to them.

Piezoelectric differential pressure vortex sensor

Microminiature resonant sensor structures are prepared according to micromachining/microfabrication techniques, which structures include thin-film deposits of piezoelectric materials. Such piezoelectric deposits may be excited electrically by including metallized conductive paths during fabrication, or optically. The resonant frequency of the sensor structure is varied by subjecting it to a physical variable, or measurand, such as pressure, temperature, flow rate, etc. Similarly, the resonant frequency of the devices may be detected electrically or optically. The microminiature resonant structures include ribbons and wires, hollow beam and cantilevered hollow beams, and single- and double-ended double beam resonant structures such as tuning forks.

Resonant sensor and method of making same

An optically driven, electromagnetically oscillating resonant sensor subjected to a stress force wherein the optical driving energy and the optically communicated signal generated in response to the stress force are both communicated a substantial distance along a single optical fiber. A portion of the supply energy drives the oscillatory mechanism and a portion is reflected to a frequency detector by the shuttering action of the resonant element. The device may be configured so as to be electrically driven and optically sensed, optically driven and electrically sensed, or both optically driven and optically sensed for maximum retrofit versatility in past, present, and future process control systems.

Fiber optic remote sensor

Differential-pressure measuring apparatus comprising a casing providing a closed chamber filled with fluid and divided into two sections by a pressure-responsive element. The input pressures are applied to the two chamber sections respectively to develop a corresponding force on the pressure-responsive element. A sealed evacuated housing of non-magnetic material is in one chamber section and contains a double-tuning-fork (DTF) the resonant frequency of which varies with longitudinal tension force applied to the DTF. The force developed by the pressure-sensitive element is coupled by magnetic elements through the wall of the housing and to the DTF so as to control the resonant frequency of the DTF in accordance with the differential pressure to be measured. The DTF is activated to produce an output signal reflecting the differential pressure.

Growing community of inventors

Norfolk, MA, United States of America

Gordon W Chitty