Infrared analyzer

• US 4,692,622 A
• Filed: 12/03/1985
• Issued: 09/08/1987
• Est. Priority Date: 12/04/1984
• Status: Expired due to Fees

• Current Assignee: Fuji Electric Company Limited 1-1 Tanabeshinden Kawasaki-Ku Kawasaki-Shi Kanagawa Japan, Fuji Electric's Research And Development, Ltd.
• Original Assignee: Fuji Electric's Research And Development, Ltd., Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Taniguchi, Harutaka, Fumoto, Takafumi
• Primary Examiner(s): Howell, Janice A.
• Assistant Examiner(s): Hannaher, Constantine
• Application Number:
  US06/803,967
• Time in Patent Office: 644 Days
• Field of Search: 250/345, 250/344, 250/343, 356/437
• US Class Current: 250/343
• CPC Class Codes: G01N 21/37 using pneumatic detection opto-acoustic detection G01N21/1702

Abstract

An infrared analyzer where infrared radiation is passed through a measurement cell containing a material that includes a component that absorbs infrared radiation. The radiation exiting the measurement cell passes into a first detector, through an optical filter to a second infrared radiation detector. By analyzing the outputs from each detector and by knowing the characteristics of the optical filter, the concentration of certain infrared absorbing components in the material can be determined.

Claims

1. An infrared analyzer comprising;

a source of infrared radiation;

a measurement cell for receiving material to be analyzed and transmitting said radiation therethrough, said material containing a first component which absorbs infrared radiation of a first wavelength and a second component which absorbs infrared radiation of a second wavelength;

an infrared detecting means, said detecting means including

a first detector, said first detector comprising a first detecting chamber and a second detecting chamber, said detecting chambers having different path lengths, said first detector measuring the amount of infrared radiation absorbed by said first component and generating a first detector output signal;

an optical filter for absorbing infrared radiation of said second wavelength;

a second detector, sensitive to infrared radiation in the wavelengths other than said first wavelength and said second wavelength, said second detector measuring the amount of infrared radiation passed through said first detector and said optical filter and generating a second detector output signal; and

means for using the first and second detector output signal to determine the concentration of said first component in said material.

2. The analyzer of claim 1 wherein said analyzer includes means for focusing infrared radiation to said second detector.

3. The analyzer of claim 1 wherein said optical filter includes water.

4. The analyzer of claim 1 wherein said optical filter contains an aqueous solution.

5. The analyzer of claim 1 including means for collimating said infrared radiation passing through said measurement cell, said collimating means being disposed to direct said radiation parallel to the axis of said measurement cell.

6. An infrared analyzer comprising:

a source of infrared radiation;

a measurement cell adapted to receive material to be analyzed wherein said material contains a first component which absorbs infrared radiation of a first wavelength and a second component which absorbs infrared radiation of a second wavelength and to transmit said radiation therethrough;

a reference cell adapted to contain a gas non-absorptive of infrared radiation;

an infrared detection means including

a first detector, said first detector having a first detector section adapted to measure the amount of infrared radiation absorbed by said first component and a second detector section adapted to measure the amount of infrared radiation absorbed by said gas non-absorptive of infrared radiation, wherein a first portion of infrared radiation passes through said measuring cell into said first detector section and a second portion of infrared radiation passes through said reference cell into said second detector section, said first detector generating a first output signal corresponding to infrared radiation measured thereby;

an optical filter adapted to absorb infrared radiation of said second wavelength;

a second detector, sensitive to infrared radiation having wavelength other than said first wavelength and said second wavelength, adapted to measure the amount of infrared radiation passed through said first detector section and said optical filter, said second detector generating a second detector output signal corresponding to the infrared radiation measured thereby; and

means for using the first and second detector output signals to determine the concentration of said first component in said material.