The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 06, 1990
Filed:
Jan. 30, 1989
A Gerrit Crawford, White Bear Lake, MN (US);
Douglas C Morrison, Shoreview, MN (US);
Medical Graphics Corporation, St. Paul, MN (US);
Abstract
A cold-cathode gas discharge device is coupled between a gas sample inlet and a high vacuum and includes spaced-apart electrodes which, when coupled across a high voltage DC power supply, causes a glow-discharge to be set up within the device with the intensity of the emitted light being proportional to the percentage of a given gas contained within a gas mixture introduced through the sampling inlet. In accordance with the present invention, the glow-discharge device contains a tubular pathway which is bent at a point intermediate the spaced electrodes so that they are not co-linear along the tubular path. A photodetector is sighted coaxially with the downstream leg of the bent pathway and, as such, senses the light emitted in a longitudinal direction rather than in a transverse direction. As such, errors due to fogging of the pathway over time by electrode material or the like and movement of the cathode dark-spaced and Faraday dark-space within the tube do not alter the measurable radiation.