Therm-o-disc, Incorporated

David Reynolds

Bernd D Zimmermann

Prasad S Khadkikar

Richard L Gerich

Hank E Millet

James A Tennant

Richard E Welch

Donald G Cunitz

Thomas C Anderson

Philip S Young

Bernd D Zimmerman

A fuel fired appliance exhaust gas parameter sensor for continually detecting gas parameter emissions, such as CO, NOx and O, may be located above the appliance near the appliance exhaust outlet. The sensor may be located near or under a draft hood located near the exhaust outlet. The sensor remains relatively cool by draft air moving from outside the draft hood and into a chimney, the draft being hastened by the heated, rising chimney gases. A sensor bracket may be attached to the appliance and the sensor to appropriately position the sensor under the draft hood. Alternatively, the sensor may be located on a tube that continually samples combustion exhaust. The tube may be located outside of the draft hood perimeter to maintain a low sensor temperature, while multiple tube coils around the exhaust outlet may be used to further cool the sampled gas.

Flue sensor for gas fired appliance

A fluid flow rate sensor includes a detection circuit which generates a first signal corresponding to an output voltage of a bridge circuit, and a second signal corresponding to a fluid temperature. A control module can more accurately and quickly determine the fluid flow rate based on the first signal, the second signal and a look-up table. The look-up table includes a plurality of curves plotted according to data, indicating relationship among the fluid temperature, the output voltage and the fluid flow rate. The fluid flow rate sensor is inherently temperature compensated and has a shorter response time.

Fluid flow rate sensor and method of operation

An improved liquid level sensor is disclosed which provides a reliable and simple device for accurately determining the level of a liquid within a vessel. The sensor utilizes a plurality of thermocouple junctions grouped in pairs with the pairs being spaced along a line extending generally in the direction in which the liquid level may vary. A first thermocouple junction of each pair is located in relatively close thermal proximity to an electrically powered heater and the second of each pair of thermocouple junctions is spaced away from the heater. The thermocouple junctions are connected in series and produce a signal indicative of the level of liquid along the sensor. Alternatively, a single threshold liquid level sensor is provided for use with a hermetic interface to provide a signal to indicate a level of liquid within a container. Additionally, a pressure sensing circuit may also be incorporated with either liquid level sensor.

Liquid level sensor

An improved liquid level sensor is disclosed which provides a reliable and simple device for accurately determining the level of a liquid within a vessel. The sensor of the present invention utilizes a plurality of thermocouples grouped in pairs with the pairs being spaced along a line extending generally in the direction in which the liquid level may vary. A first thermocouple of each pair is located in relatively close thermal proximity to an electrically powered heater and the second of each pair of thermocouples is spaced away from the heater. The thermocouples are connected in series and produce a signal directly indicative of the level of the liquid along the sensor. Additionally, a pressure sensing circuit may also be incorporated with the liquid level sensor.

A temperature control circuit provides for optical isolation, dry start protection, dedicated load control, manual reset, and relay control in hot water heaters and related applications. The control circuit removes power from a load at a first temperature, and includes a first optical isolation device, a first diode temperature sensor, and a first switching mechanism. The first optical isolation device controls operation of a power source, where the power source is provided to the load, such as a hot water heater heating element. The first diode temperature sensor is biased to provide a switching signal at the first temperature. The first switching mechanism is disposed between the first diode temperature sensor and the first optical isolation device, where the first switching mechanism disengages operation of the first optical isolation device in response to the switching signal. The control circuit can further include a high limit cycling circuit for disengaging operation of the power source at the second temperature. A latching circuit can be used to maintain the temperature control circuit in a switched state until a manual reset occurs.

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Galion, OH, United States of America

David Reynolds