Dwyer Instruments, Inc.

Stephen S Clark

Brian Lee Palmer

John M Donnelly

Octavian G Condrea

A manometer for measuring fluid pressure having a first pressure sensor and a second pressure sensor that is inverted with respect to the first pressure sensor. The first pressure sensor generates a first electrical output signal corresponding to a fluid pressure measured by a first diaphragm of the first pressure sensor. The second pressure sensor generates a second electrical output signal corresponding to a fluid pressure measured by a second diaphragm of the second pressure sensor. The first and second electrical output signals are combined into a combined electrical output signal. False readings of a change in/pressure measured by the first pressure sensor and measured by the second pressure sensor in each of the first and second electrical output signals, due to movement of the manometer, are cancelled by one another in the combined electrical output signal to provide an accurate pressure measurement regardless of movement of the manometer.

Manometer having dual pressure sensors

A shoe tester for use in environments where static electricity sparking must be eliminated between so called Electrostatic Dissipating (ESD) shoes and the floor, by personnel wearing a pair of such shoes, wherein the tester comprises a pair of metallic electrically conductive shoe plates secured together in spaced but side-by-side relation resting on such floor on insulated studs or the like, on which the person wearing the shoe stands with his shoes on the respective plates, and a 'plug-in' electronic circuit for measuring the resistance of such person and the shoes, including a scale and a pointer arm associated with the tester for actuation by the circuit when electrically energized by any grounded 115 volt alternating current outlet available for indicating acceptable and unacceptable shoe resistances, wherein the circuit includes an amplifier arrangement that permits the resistance measurements to be made to be in the range of 2,000 megohms.

Stand-on type resistance tester for electrostatic dissipating shoe

A differential pressure switch assembly that includes a conventional snap action switch for controlling the off-on modes of operation of state of the art equipment, which assembly comprises a high pressure plate that defines the high pressure cavity and a high pressure port of restricted size therefor, a low pressure plate that defines a first subchamber of the assembly low pressure cavity and a low pressure port therefor, a diaphragm clamped between the high and low pressure plates and separating the switch assembly high and low pressure cavities, a piston mounted in the low pressure plate for movement perpendicularly of the assembly diaphragm and biased toward the diaphragm by an adjustable range spring device, the range spring of which can be adjusted to provide the set point for the switch assembly, with the range spring device being formed to dispose the range spring in a second low pressure subchamber that is in open communication with the first low pressure subchamber to form a composite low pressure chamber, and with the low pressure plate journaling a rotary take out shaft that is coupled to the piston within the low pressure composite chamber and actuates a mechanical mechanism for utilizing the diaphragm motion for a particular set point of a switch assembly to actuate the snap action switch of same free of high deadband.

Growing community of inventors

Michigan City, IN, United States of America

Stephen S Clark