Gas analyzer

• US 4,180,734 A
• Filed: 01/26/1978
• Issued: 12/25/1979
• Est. Priority Date: 02/18/1977
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Gedeon, Andras
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Fields, Carolyn E.
• Application Number:
  US05/872,449
• Time in Patent Office: 698 Days
• Field of Search: 250/338, 250/339, 250/343, 250/345, 250/344, 250/373, 250/349, 356/51, 356/88, 356/93, 356/97, 128/2 C
• US Class Current: 250/345
• 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 21/3504 for analysing gases, e.g. multi-gas analysis

Abstract

An illustrative embodiment shows infrared radiation divided into two beams which impinge on respective detectors via respective stationary filters, so as to provide measures of two constituents of a mixture of gases used for mixed anaesthesia. The same angled mirrors which provide the measurement beams may also be reflective on their sides toward the infrared source to provide reference beams to the filters and detectors such that the detectors may alternately sense the measurement and reference beams with the aid of beam interrupters.

Claims

1. A gas analyzer having a respiratory tube through which the respiratory gas flows for analysis, a radiation source which radiates through the respiratory tube, radiation receiving means, reflector means which direct the radiation onto the radiation receiving means, and several radiation filters, each of which is assigned to one gas, characterized in that the reflector means (14, 15, 16) are constructed and arranged so that the radiation is divided into two beams of radiation (18, 19) each of which exits through a window (20, 21, 20a, 21a), that the receiving means comprises two radiation detectors (22, 23), each of which detects one beam of radiation (18, 19) issuing from the respiratory tube (5), and that the radiation filters (24, 25), each assigned to a specific gas, are arranged in each case before a respective one of the radiation detectors (22, 23), and further characterized in that the reflector means comprises concave reflector means (14) disposed opposite the radiation source (12), and two obliquely arranged plane reflectors (15, 16) lying symmetrically at an angle to one another opposite the concave reflector means (14), that a clearance (17) is left between the plane reflectors (15, 16) through which the radiation of the radiation source (12) is focused to a beam of radiation striking the concave reflector means (14) and that the angle of inclination of the plane reflectors (15, 16) is selected so that they each reflect a portion of the beam of radiation after reflection at the concave reflector means (14), in each case through a window (20, 21).

2. A gas analyzer having a respiratory tube through which the respiratory gas flows for analysis, a radiation source which radiates through the respiratory tube, radiation receiving means, reflector means which direct the radiation onto the radiation receiving means, and several radiation filters, each of which is assigned to one gas, characterized in that the reflector means (14, 15, 16) are constructed and arranged so that the radiation is divided into two beams of radiation (18, 19) each of which exits through a window (20, 21, 20a, 21a), that the receiving means comprises two radiation detectors (22, 23), each of which detects one beam of radiation (18, 19) issuing from the respiratory tube (5), and that the radiation filters (24, 25), each assigned to a specific gas, are arranged in each case before a respective one of the radiation detectors (22, 23), and further characterized in that the reflector means comprises concave reflector means (14) disposed opposite the radiation source (12), and two obliquely arranged plane reflectors (15, 16) lying symmetrically at an angle to one another opposite the concave reflector means (14), that a clearance (17) is left between the plane reflectors (15, 16) through which the radiation of the radiation source (12) is focused to a beam of radiation striking the concave reflector means (14) and that the angle of inclination of the plane reflectorv (15, 16) is selected so that they each reflect a portion of the beam of radiation after reflection at the concave reflector means (14), in each case through a window (20, 21), and further characterized in that the obliquely arranged reflectors (15, 16) are reflective on both sides, that the radiation of the radiation source (12) is also aligned directly onto the side of the reflectors (15, 16) which is facing the radiation source (12), and the reflectors (15, 16) are aligned so that they direct this primary radiation in separate beams of radiation (26, 27) via the filters (24, 25) onto the detectors (22, 23) so that each detector (22, 23) is struck by a beam of radiation (26, 27) via the assigned filter (24, 25), and that a radiation interrupter (28, 29) is disposed before each detector (22, 23) which alternately interrupts the two beams of radiation (18, 19, and 26, 27) striking the detectors (22, 23).