Rosemount Inc.

James A Ruf

Robert C Bohara

John Paul Schulte

Thomas A Knecht

A platinum resistance thermometer is formed in a process which includes the defining of a path for the resistance thermometer in an inert material deposited in a layer on the substrate. The substrate surface is exposed in the path, and the inert material forms a negative pattern for the path. The resistive material for the thermometer is then deposited on both the substrate surface exposed in the path and on the surfaces of the inert material remaining on the substrate. After this, the inert material is etched away, and the resistive material deposited on top of the inert material is then loose and can be removed leaving a strip of resistive material in the desired path for forming the resistive thermometer. The strip has low contamination and impurities to more easily reach the desired temperature coefficient of resistance of the strip forming the thermometer.

Method for forming a platinum resistance thermometer

A pressure transducer has a stress isolator layer which permits the sensor to be non-resiliently mounted (hard mounted) to a mounting surface that in turn is subjected to strain. The strain of the mounting surface tends to induce undesired stress in the sensing diaphragm, and the present stress isolator layer minimizes the amount of stress that is transferred to the measuring diaphragm, to thereby reduce error. The spring preferably comprises a silicon leaf0type spring, with or without isolating slots, and is used in various combinations of diaphragms that are sensitive to pressure. The deflection of the diaphragm in response to pressure can be measured in any desired known manner such as with strain gage resistors, or through capacitive sensing.

Pressure transducer with stress isolation for hard mounting

A platinum resistance therometer is formed in a process which includes the defining of a path for the resistance thermometer in an inert material deposited in a layer on the substrate. The substrate surface is exposed in the path, and the inert material forms a negative pattern for the path. The resistive material for the thermometer is then deposited on both the substrate surface exposed in the path and on the surfaces of the inert material remaining on the substrate. After this, the inert material is etched away, and the resistive material deposited on top of the inert material is then loose and can be removed leaving a strip of resistive material in the desired path for forming the resistive thermometer. The strip has low contamination and impurities to more easily reach the desired temperature coefficent of resistance of the strip forming the thermometer.

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Maple Grove, MN, United States of America

James A Ruf