Gas analyzer

• US 3,951,607 A
• Filed: 11/29/1974
• Issued: 04/20/1976
• Est. Priority Date: 11/29/1974
• Status: Expired due to Term

• Current Assignee: Biochem International, Inc.
• Original Assignee: Searle Cardio-Pulmonary Systems Incorporated (Pfizer Inc.)
• Inventors: Fraser, Robert B.
• Primary Examiner(s): Reese, Robert M.
• Application Number:
  US05/528,089
• Time in Patent Office: 508 Days
• Field of Search: 23/254 E, 23/254 R, 23/255 E, 23/255 R, 23/232 E, 23/232 R, 356/187, 356/178, 250/226, 250/564, 250/573, 250/575, 250/576, 313/218, 313/217 X
• US Class Current: 422/84
• CPC Class Codes: A61B 5/083 Measuring rate of metabolism by using breath test, e.g. measuring rate of oxygen consumption
• CPC Class Codes: G01N 21/69 specially adapted for fluids , e.g. molten metal
• CPC Class Codes: G01N 21/72 using flame burners

Abstract

A gas analyzer especially for pulmonary use has a frame supporting a centrally mounted radiation chamber of about 10 to 30 millimeters (0.4 to 1.2 inches) substantially uniform inside diameter, having a circular-cylindrical glass wall closed by molybdenum protected aluminum ends connected in an electrical circuit to constitute an anode and a cathode. Leading from a patient'"'"'s breathing tube is a conduit passing through a regulating valve and axially through the cathode, the conduit having an inside diameter of about 0.060 inches. The chamber is subjected to subatmospheric pressure through a duct of from about one-eighth to one-quarter inches inside diameter, passing through the anode to a vacuum pump. Arrayed equidistantly from the axis and around the chamber are several radiation detection devices, each connected to a display device. There are individual filters interposed between the chamber and at least some of the detecting devices.

Claims

1. A gas analyzer especially for pulmonary use comprising:

a patient'"'"'s breathing tube, a cylindrical analyzing chamber of insulating material having electrical conductive ends and being of substantially uniform internal diameter of from 0.4 to 1.2 inches between said ends, means including a conduit of a diameter of from 0.04 to 0.08 inches extending axially through one of said ends and connecting said chamber to said tube, means including a duct of a diameter of from 0.125 to 0.25 inches extending axially through the other of said ends for connecting said chamber to subatmospheric pressure and to thereby draw gases from said tube through said chamber, means for applying to said ends of said chamber a voltage difference to cause radiation from gas in said chamber, a plurality of radiation detection devices arrayed around said chamber, radiation filters between said chamber and at least some of said detection devices, each radiation filter being for a particular one of a plurality of gases in said chamber, and means for displaying the response of each of said detection devices.

2. A gas analyzer as in claim 1 in which said applying means includes an axially perforate cathode and an axially perforate anode respectively interposed between said conduit and said duct.

3. A gas analyzer as in claim 1 including a radiation opaque shield around said chamber, said shield having a radiation orifice therein for passing radiation from said chamber to one of said filters.

4. A gas analyzer as in claim 3 in which said shield is slidable on said chamber.