Abstract:
A system for determining a gas pressure or gauging a vacuum in a hermetically sealed enclosure. One or more heater structures and one or more temperature sensor structures situated on a substrate may be used in conjunction for measuring a thermal conductivity of a gas in the enclosure. Each heater has significant thermal isolation from each sensor structure. Electronics connected to each heater and sensor of their respective structures may provide processing to calculate the pressure or vacuum in the enclosure. The enclosure may contain various electronic components such as bolometers.
Abstract:
A method and apparatus for measuring gas pressure by combining an ionization gauge with at least one other vacuum sensor. Nonvolatile memory coupled to the vacuum gauge contains calibration parameters unique to each individual sensor based on factory calibration. The nonvolatile memory may contain calibration parameters for a heat-sensitive vacuum sensor to compensate for the temperature gradients generated by the ionization gauge. The calibration parameters are a function of calibration data determined when the ionization gauge is both on and off. The nonvolatile memory may store a window of measurement data of the vacuum gauge that is updated at predetermined time intervals and in response to an event, such as an error event, to aid in investigating the cause of vacuum gauge malfunction or failure.
Abstract:
The invention relates to a measuring device with at least one microsensor (5). The at least one microsensor has at least two chambers (20, 30) which are filled with a gas. Said chambers (20, 30) are interconnected by at least one channel (40) and are sealed off in such a way that they are outwardly gas-tight. A detection device (70) for detecting a gas stream flowing through the at least one channel (40) is provided, said gas stream being caused by different pressures being present in the chambers. The invention also relates to a method for producing an inventive microsensor.
Abstract:
The invention relates to the determination of the gas pressure in an evacuated thermal insulating board (9) having an insulating core (1) covered by a film (2). The inventive device comprises an assembly, which is integrated between the insulating core and the covering film of the thermal insulating board and which has a body that acts as a heat sink (3) (Al, Co, Fe, ceramic), and the body's thermal conductivity and thermal capacity relative to volume are greater than those of the insulating core. Said assembly also comprises a test layer (4) (0.3 mm nonwoven fabric made of plastic and glass fibers), which is arranged between the heat sink and the covering film and has a defined thermal conductivity that changes according to the gas pressure inside the evacuated thermal insulating board. From the exterior, a sensor device is applied to or pressed against the test device, which is placed inside the evacuated thermal insulating board and which is covered by the covering film. Said sensor device comprises a body (5) (coppered steel 78 DEG C, thermoelement (6)) having a distinctly different temperature than that of the test device (heat sink) whereby creating a heat flux, which is influenced by the thermal conductivity of the test layer, said thermal conductivity varying according to the gas pressure inside the thermal insulating board, and the magnitude of this heat flux is metrologically determined. The heat sink (3) can be provided in the form of a bottom part of a container for a getter material.
Abstract:
A miniaturized silicon based thermally controlled vacuum sensor (10) uses thin film resistors (not shown) on a membrane (20) in a minute measuring chamber (14) to accurately detect vacuum pressures in the range of 760 Torr to 1 x 10 Torr. The configurations of the measuring chamber (14) and gas diffusion port (19) of the sensor structure insure that heat transfer from the membrane (20) is predominantly conductive over the pressure detection range to provide linear output up to 0.1 Torr. A microprocessor (not shown) is used to control and measure power required to maintain a predetermined temperature differential between a sensing resistive element (not shown) on the membrane and an ambient temperature sensing element (not shown) of the sensor base (12) from analog voltage and current values. Pressure detection errors introduced by ambient temperature variations are minimized by measuring power dissipated into the gas. Analog and digital converters for both current and voltage signals use a SIGMA - DELTA conversion method to reject electrical noise by an averaging technique to produce stable signal detection of pressure down to 1 x 10 Torr. The sensor is thermally stable over an ambient temperature range of 0-50 DEG C at pressures between 10 to 760 Torr.
Abstract:
Micro-Pirani gauge vacuum gauges are described that use low-thermal conductivity support elements. A micro-Pirani gauge or vacuum sensor can include a heating element operative to heat a gas and to produce a signal corresponding to the pressure of the gas; a platform configured to receive the heating element, with the platform having a first coefficient of thermal conductivity; and a support element connected to a substrate and configured to support the platform with the heating element within an aperture disposed in the substrate, with the support element having a second coefficient of thermal conductivity, where the second coefficient of thermal conductivity is less than the first coefficient of thermal conductivity. Multimode pressure sensing including a micro-Pirani gauge are also described.
Abstract:
Die Erfindung richtet sich auf eine Vorrichtung und ein Verfahren zur Bestimmung des Gasdruckes in einer evakuierten Wärmedämmplatte (9) mit einem von einer Folie (2) umhüllten Dämmkern (1). die erfindungsgemässe Vorrichtung umfasst eine zwischen Dämmkern und Umhüllungsfolie der Wärmedämmplatte eingebaute Anordnung mit einem als Wärmesenke (3) (AL, Co, Fe, Keramik) wirkenden Körper, dessen Wärmeleitfähigkeit und volumenbezogene Wärmekapazität grösser sind als die betreffenden Grössen des Dämmkerns, und mit einer zwischen der Wärmesenke und der Umhüllungsfolie angeordneten Probeschicht (4) (0,3mm Faservliese aus Kunstoff, Glasfasern) mit einer definierten Wärmeleitfähigkeit, die sich als Funktion des Gasdruckes in der evakuierten Wärmedämmplatte. über der in der evakuierten Wärmedämmplatte angeordneten, von der Umhüllungsfolie abgedeckten Probevorrichtung von aussen eine Sensoreinrichtung angelegt oder -gepresst, die einen Körper (5) (verkupferter Stahl, 78 0 C Thermoelement 6) mit einer deutlichen Temperaturdifferenz zu der Probevorrichtung (Wärmesenke aufweist, so dass ein von dem in Abhängigkeit von dem Gasdruck im Inneren der Wärmedämmplatte variierenden Wärmeleitfähigkeit der Probeschicht beeinflusster Wärmestrom hervorgerufen wird, dessen Grösse messtechnisch erfasst wird. Die Wärmeseke (3) kann als Bodenteil eines Behälters Für ein Gettermaterial ausgebildet sein.
Abstract:
Micro-Pirani gauge vacuum gauges are described that use low-thermal conductivity support elements. A micro-Pirani gauge or vacuum sensor can include a heating element operative to heat a gas and to produce a signal corresponding to the pressure of the gas; a platform configured to receive the heating element, with the platform having a first coefficient of thermal conductivity; and a support element connected to a substrate and configured to support the platform with the heating element within an aperture disposed in the substrate, with the support element having a second coefficient of thermal conductivity, where the second coefficient of thermal conductivity is less than the first coefficient of thermal conductivity. Multimode pressure sensing including a micro-Pirani gauge are also described.
Abstract:
An electronic thermistor-based vacuum gauge and systems and methods of calibration and operation of the same that require no calibration against a known vacuum standard to obtain high accuracy through broad vacuum and ambient temperature ranges. Additional features of the invention include a construction and method of improving battery life, a construction and method of detecting faulty vacuum sensors, a method for determining the state of calibration of a vacuum sensor, a method of quantifying vacuum leak rates, and a method of automatically alerting an operator when an evacuation process has concluded.