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. 21, 1978
Filed:
Jun. 14, 1976
Paul E Stoft, Menlo Park, CA (US);
John A Bridgham, Palo Alto, CA (US);
Robert L Chaney, Cupertino, CA (US);
Charles M Hill, Los Altos, CA (US);
John K Lazier, Palo Alto, CA (US);
Barry G Willis, Palo Alto, CA (US);
Jacob Y Wong, Framingham, MA (US);
Moshe A Fostick, San Francisco, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A gas analyzer is provided which is particularly suited for making transcutaneous measurement of the CO.sub.2 concentration in the blood. In accordance with one embodiment of the invention, sample gases from the body are circulated in a cavity of the device. A rotating wheel in the cavity includes two reference cells and a sample cell which are sequentially rotated into the optical path between a source and a detector. Three signals are thereby provided which may be combined to give an output indication of the CO.sub.2 concentration in the body fluids. In a preferred embodiment, the sample cell is an 'inverted cell' being in open communication with the sample gas circulating in the device so that the gas in the sample cell is a portion of the circulating gas which also surrounds the two reference cells. An output indication is thereby obtained which is insensitive to contaminants in the sample. In accordance with another embodiment, the sample cell is isolated from the region surrounding the wheel and positioned so as to be presented in series with the reference cells in the optical detection path. In preferred embodiments, the rotating wheel contains a number of permanent magnets which interact with a number of electromagnets driven in sequence to provide rotation of the wheel.