Eldec Corporation

William E Chiles

David L Brodeur

Bruce E Johnson

Jack V Peterson

LeRoy E Vetsch

Duane E Palmer

The impeller and drum of a motorless in-line mass flowmeter are constructed with small optical targets having high reflectivity. Light is pulsed toward the path of rotation of the targets through optical fibers. The pulse width is small in comparison to the delay between pulses. Reflections of the pulses from the optical targets are conveyed by a single output fiber to a remote location where the optical pulses are converted to electrical pulses. The electrical pulses can be analyzed to determine the speed of the impeller and the deflection angle of the impeller relative to the drum, for accurate determination of the mass flow rate of liquid passing through the flowmeter.

Optical pickup and signal analyzing system for mass flowmeters

A fluid flowmeter, of a type including a housing and a fluid flow measurement assembly rotatable therein which is driven by a turbine, is described in detail to illustrate a limitation on low flow rate operational capability and a related problem of contaminant particle malfunctions. A specific flowmeter used for such illustration is a typical prior art motorless mass flowmeter including a turbine secured to and rotatable with a shaft which in turn rotates a downstream impeller by means of a spring, the impeller being independently supported for rotation, so that relative deflection between the impeller and the shaft is a measure of mass flow rate. To minimize fluid leakage around a peripheral surface of the turbine in proximity to the housing in order to achieve low flow rate operation, while yet avoiding stoppage of the turbine due to contaminant particles being lodged in or near the leakage path, a shroud member is utilized upstream of the turbine which comprises a hollow member of revolution rotatable with the turbine which has a first end secured to the turbine, in a fluid-tight seal, at points radially outward of a plurality of turbine drive means in the turbine and which tapers to a second end, proximate to a fluid inlet opening, to form a rotatable fluid seal with a sealing means surrounding the fluid inlet opening.

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Kirkland, WA, United States of America

William E Chiles