Invensys Systems, Inc.

Donald S McKinlay

Stephen B Talutis

Michael Mason Bower

John Kevin Quackenbush

Daniel G Tower, Iii

Gordon L Hamilton

A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flowpaths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof.

Non-metallic flow-through electrodeless conductivity sensor and leak detector

A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flow paths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof. A temperature detector is supported within an electrically non-conductive holder extending into the fluid flow path, so that the detector is free from physical contact with the fluid. An optional enclosure is provided with ports to enable a user to purge any gas permeating the conduit walls.

Non-metallic flow-through electrodeless conductivity sensor with leak and temperature detection

An indirect clamping topology may be used to protect against the damaging effects of an electrostatic discharge event. An input node of a device is protected by a guard. The guard is driven by a signal from a unity-gain amplifier that flows through a resistance. The input node is clamped to the guard by a diode, and the guard is clamped to a low-impedance rail by another diode. The resistance of the low-impedance rail is less than that of the resistance through which the signal from the unity-gain amplifier flows, so that voltage resulting from the event flows to the low-impedance rail and not to the amplifier.

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Wareham, MA, United States of America

Donald S McKinlay