Oxygen analyzer

• US 4,960,568 A
• Filed: 09/14/1988
• Issued: 10/02/1990
• Est. Priority Date: 10/02/1987
• Status: Expired due to Fees

• Current Assignee: Osaka Sanso Kogyo Ltd. (Air Liquide SA)
• Original Assignee: Osaka Sanso Kogyo Ltd. (Air Liquide SA)
• Inventors: Makihara, Akira, Matsumoto, Yoshiro
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Johnston, Jill
• Application Number:
  US07/244,206
• Time in Patent Office: 748 Days
• Field of Search: 422/93, 422/83, 422/103, 422/94, 137/599, 137/599.1, 73/23, 73/23.1, 73/155, 128/205.26, 55/68, 55/88, 350/266, 204/409, 436/178, 436/136, 436/181, 251/335.2
• US Class Current: 422/83
• CPC Class Codes: G01N 33/0014 by eliminating a gas by a chemical reaction G01N33/0013; a chemical reaction taking place or a gas being eliminated in one or more analysing channels G01N33/0024
• CPC Class Codes: G01N 33/0024 a chemical reaction taking place or a gas being eliminated in one or more channels
• CPC Class Codes: Y10T 436/207497 Molecular oxygen
• CPC Class Codes: Y10T 436/25875 Gaseous sample or with change of physical state

Abstract

An improved oxygen analyzer device is disclosed which comprises a gas flow passage having inlet and exhaust ports, an oxygen concentration detector in proximity to the exhaust port and first and second parallel intermediate flow passages, one of which contains a purifier to remove oxygen from the gas flowing therethrough. The device is characterized by the use of metal, diaphram-type, three-way valves in the branch-off and junction points between the intermediate flow passages. The valves eliminate dead space in conventional devices that extends both the calibration and analysis time of such devices.

Claims

1. An oxygen concentration analyzer comprising:

a gas flow passage having a gas inlet port at one end thereof for connecting a gas source to the gas flow passage in an atmospheric environment and a gas exhaust port at the opposite end for discharging a gas from the gas flow passage;

an oxygen concentration detector disposed in the gas flow passage in proximity to the gas exhaust port;

a portion of the gas flow passage between the gas inlet port and the oxygen concentration detector comprising first and second intermediate flow passages positioned to provide parallel intermediate flow paths for the gas to the oxygen concentration detector and connected to the gas inlet port via a branch-off point and connected to the oxygen concentration detector via a junction point;

a purifier disposed in the first intermediate flow passage for removing oxygen from the gas flowing therethrough;

first and second metal diaphragm type three-way valves, positioned at the branch-off point and junction point between the first and second intermediate flow passages and each of said first and second three-way valves respectively having a set of first, second, and third ports connected to the inlet port and the first and second intermediate flow passages and a set of fourth, fifth, and sixth ports connected to the oxygen concentration detector and the first and second intermediate flow passages;

the first and second three-way valves designed to be selectively switchable between two positioned in which in a first of the positions, the first, second, fourth, and fifth ports of each of the first and second three-way valves are opened to allow the gas to flow through the first intermediate flow passage and the sixth port of the second three-way valve is closed to prevent the flow of gas in the second intermediate flow passage, and in which in a second of the positions, the first, third, fourth, and sixth ports of each of the first and second three-way valves are opened so that gas may flow through the second intermediate flow passage and the second port of the first three-way valve is closed to prevent the flow of gas in the first intermediate flow passage;

whereby, when the first and second three-way valves are set in the first of the positions and gas flows through the purifier before introduction into the oxygen concentration detector to calibrate the oxygen concentration detector and the second intermediate flow passage is blocked off at the junction point to prevent the contamination of the gas after the removal of oxygen therefrom with the gas in the second intermediate flow passage and when the first and second three-way valves are set in the second of the positions, the gas flows directly into the oxygen concentration detector to detect the oxygen content thereof and the first intermediate flow passage is blocked at the branch-off point to alternately allow the gas source to be connected to the inlet port without air entering the second intermediate flow passage and eventually contaminating the gas passing through the purifier and used in calibrating the oxygen concentration detector.

2. An oxygen concentration analyzer according to claim 1, further comprising a stop valve positioned in said first intermediate flow passage between the purifier and the second three-way valve, the stop valve being selectively switchable between an open position when the first and second three-way valves are set in the first of the positions and a closed position when the first and second valves are set in the second of the positions.

3. An oxygen concentration detector according to claim 1, wherein the fifth port of the second three-way valve is closed when it is set in the second of the positions to prevent the contamination of the gas to be detected flowing through the second intermediate flow passage with the gas in the first intermediate flow passage, the oxygen having been removed therefrom by the purifier.