Krypton hygrometer

• US 4,526,034 A
• Filed: 05/07/1984
• Issued: 07/02/1985
• Est. Priority Date: 05/07/1984
• Status: Expired due to Term

• Current Assignee: Campbell Scientific
• Original Assignee: Campbell Scientific
• Inventors: Campbell, Gaylon S., Tanner, Bertrand D., Gauthier, Robert V.
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): ROSKOS, JOSEPH
• Application Number:
  US06/607,750
• Time in Patent Office: 421 Days
• Field of Search: 73/336.5, 73/335, 73/30, 250/372, 250/504 R
• US Class Current: 73/335.01
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence

Abstract

An improved spectroscopic hygrometer includes a krypton-filled source tube that produces emissions at 123.58 nm for selective absorption by water vapor in a gaseous sample. The method for measuring water vapor density requires generation of ultraviolet radiation from a krypton source, receipt of the radiation by a detector, and passage of a gaseous sample through the radiation that is directed to the detector. The krypton radiation has been found to be an effective source for hygrometry purposes, and a practical improvement over prior hydrogen sources.

Claims

1. In a hygrometer for measurement of water vapor density by the absorption of ultraviolet radiation, the apparatus comprising:

a krypton-filled glow discharge tube;

detector tube means for receiving radiation along a path leading from the glow discharge tube; and

a gaseous sample path intersecting the path leading from the glow discharge tube to said detector tube means.

2. The hygrometer of claim 1 wherein the krypton-filled glow discharge tube comprises a krypton vacuum ultraviolet lamp.

3. The hygrometer of claim 1 further comprising:

window means in the path leading from the glow discharge tube to the detector tube for filtering emitted radiation from the krypton tube having a wavelength substantially differing from 123.58 nanometers.

4. The hygrometer of claim 3 wherein the window means are composed of magnesium fluoride (MgF₂).

5. A method for measuring water vapor density by the absorption of ultraviolet radiation, comprising the following steps:

generating ultraviolet radiation from a krypton source having an emission line at a wavelength of 123.58 nanometers;

directing the generated radiation to a detector for measurement of the radiation received thereby;

and passing a gaseous sample through the radiation being directed to the detector.

6. The method of claim 5 further comprising the step of filtering the radiation directed to the detector to block passage of radiation having a wavelength substantially differing from 123.58 nanometers.