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US 6,474,171 B1Granted
Vacuum gauge
AssigneeThe BOC Group, Inc.
InventorsAlan Edward Holme, Waleed Ahmed Qader
Life of this patent
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Abstract
A vacuum gauge of the cold cathode type has a gauge head which includes a cathode discharge cell and an anode a portion of which is located within the cathode discharge cell. An electrically operated ignition device is located adjacent the cathode discharge cell which ignition device is protected from being operated at high pressure by an auxiliary pressure sensor.
Claims8
A vacuum gauge having a gauge head comprising:
- a cathode sleeve having an inlet at one end for communication with a vacuum to be measured;
- a cathode discharge cell located within the cathode sleeve;
- an anode, a portion at least of which is located within the cathode discharge cell;
- an electrically operated ignition device located adjacent the cathode discharge cell;
- and
- a sensor disposed at the gauge head to generate a signal of a pressure associated with the electrically operated ignition device.
3 more elements
A vacuum gauge having a gauge head comprising:
- a cathode sleeve having an inlet at one end for communication with a vacuum to be measured;
- a cathode discharge cell located within the cathode sleeve;
- an anode, a portion of which is located within the cathode discharge cell;
- and
- an electrically heated filament located adjacent the cathode discharge cell, the electrically heated filament being operable as an ignition device for liberating electrons and as a sensor responsive to thermal conductivity at the gauge head to generate a signal of a pressure associated with the electrically heated filament to protect the filament from being operated at high pressure.
2 more elements
Dependencies are inferred from the claim text.