Fluke Corporation

Calamerica Corp.

Pierre Delajoud

Robert B Haines

Thomas Lohkamp

Martin Girard

A measurement system uses a plurality of transducers that may differ from each other in at least one respect, such as having different operating principles or being made by different manufacturers. Respective measurement values obtained from the transducers are applied to a processor which provides a measured value based on the measurement values from a plurality of the transducers. The processor also provides information about the calibration drift of each of the transducers based upon a comparison between the measurement value obtained from the transducer to a value obtained from a combination of respective measurement values obtained from a plurality of the transducers. The calibration drift information provides an objective evaluation about the calibration condition of each of the transducers. When a transducer is determined to be outside of its calibration tolerance, a calibration needed alert occurs.

System and method for objective self-diagnosis of measurement device calibration condition

Embodiments of the present invention are directed toward pressure controllers and calibrators for setting or measuring pressures in test devices. In one embodiment, the pressure controller contains a dual reference pressure controller. The dual reference pressure controller is operable to maintain two different pressures relative to a reference pressure. The first pressure being a relatively fixed amount greater than the reference pressure and the second pressure being a relatively fixed amount less than the reference pressure.

System to control pressure in a test device

A gas mass flow meter includes an elongated channel extending through a high thermal mass body and a critical flow nozzle in a downstream portion of the channel. A heat exchanger is provided upstream in the channel. Gas is forced through the heat exchanger and the critical flow nozzle at a flow rate of up to 5000 slm and at sufficiently high-pressure to ensure critical flow of the gas through the critical flow nozzle. The heat exchanger brings the gas close to the temperature of the high thermal mass body. The pressure of the gas is measured upstream and downstream from the nozzle and the temperature of the gas emerging from the heat exchanger is measured. The mass flow rate of gas through critical flow nozzle is computed from the upstream pressure, downstream pressure, temperature of the high thermal mass body, density of the gas, and a dimensional characteristic of the critical flow nozzle.

Critical gas flow measurement apparatus and method

A device for accurately measuring the pressure (Pg) of very highly pressurized gas includes a cylinder ( ) having a cylindrical outer surface ( A) and a bore extending through the cylinder and an elongated piston ( ) rotatable and vertically movable in the bore, and supporting calibration weights by means of the piston. An internal reservoir ( ) is formed by providing a housing ( ) to support the cylinder, the housing including a lower portion engaging a bottom portion of the cylinder and a lower peripheral portion of the cylinder and an upper portion engaging an upper peripheral portion of the cylinder, an inner portion of the housing ( ) and a portion of the outer surface ( A). An interior of the reservoir ( ) is pressurized through a passage ( A) extending from the reservoir to pressurize gas inlet. A passage ( ) conducts pressurized oil from the reservoir into a gap between the piston ( ) and the bore.

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Neuilly sur Seine, France

Pierre Delajoud