Raytheon Company

Varian, Inc.

Peter C Lukens

Dusan Baic

Atholl Gibson

Embodiments of a pressurized gas supply are provided. In one embodiment, the pressurized gas supply includes a pressurized gas reservoir and a pressure reducer fluidly coupled to the pressurized gas reservoir. The pressure reducer is configured to reduce the pressure of gas received from the pressurized gas reservoir to a predetermined output pressure (P). A gas mixture is held within the pressurized gas reservoir at a starting pressure (P) and at a starting temperature (T). The gas mixture includes: (i) a warming gas having a positive Joule-Thomson (JT) coefficient at Tand over the pressure range P-P, and (ii) a cooling gas having a negative JT coefficient at Tand over the pressure range P-P. The cooling of the cooling gas at least partially offsets the warming of the warming gas when the gas mixture is expelled by the isothermal gas supply to achieve a desired gas output temperature.

Isothermal gas supply and method for minimizing the temperature excursion of a gas mixture released therefrom

A system for detecting leaks in a unit. The novel system includes a first mechanism for injecting a first gas into an interior or an exterior of the unit, a second mechanism for sampling gas from an exterior or an interior of the unit to determine if the first gas has leaked out of or into the unit, respectively, and a third mechanism for controlling a differential pressure between the interior and exterior of the unit during sampling. In an illustrative embodiment, the differential pressure is controlled by injecting a second gas into the exterior or interior of the unit to replace the sampled gas, and using pressure regulators to control the pressures of the first and second gases such that the differential pressure remains constant during sampling.

Leak detection system with controlled differential pressure

A pressure measurement device with protection from long-term loads and pressure shocks. The novel device includes a diaphragm adapted to deform in response to a pressure applied thereto, and a retractable support adapted to support the diaphragm during periods of non-operation. A strain gauge is attached to the diaphragm for measuring the deformation and the retractable support is designed to minimize stress on the strain gauge during periods of non-operation. The support is retracted during periods of operation to allow the diaphragm and strain gauge to function normally in response to the applied pressure. The diaphragm is disposed within a housing to form a first cavity, which is coupled to media to be measured, and a second cavity, which is set at a reference pressure. In an illustrative embodiment, the retractable support is a threaded plug inserted into the second cavity.

Pressure measurement transducer with protective device

In some embodiments, a nuclear magnetic resonance (NMR) method comprises generating an indicator of an anticipated time-averaged power for a radio-frequency (RF) pulse set, and anticipatively adjusting a cooling supplied by a cryogenic cooling fluid to an RF coil according to the indicator of the anticipated time-averaged power. The cryogenic cooling adjustment may be performed using a cryogenic fluid heater and/or a mass flow controller disposed in the cryogenic fluid path. The time difference between the start of the cooling adjustment and the start of the RF pulse set is set to be equal to the difference in timescales between the cooling effect of the cooling adjustment and the heating effect of the RF pulse set on the RF coil.

Anticipative temperature regulation of cryogenic NMR probes

An NMR apparatus, sample contained in a sample holder is ejected from an NMR probe to the top of the magnet region where a sample latching mechanism holds the sample in place without requiring a continuing flow of pressurized gas, electrical power or other outside force. The sample can then be removed and/or exchanged with another sample that is also held in place without the expenditure of gas. When ready the operator depresses a lever arm enabling the exchanged sample to move into the probe.

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Tucson, AZ, United States of America

Peter C Lukens