Abstract The invention disclosed herein relates to the measurement of the water vapor content of a gaseous environment and more particularly to the measurement of the water vapor content of the atmosphere by means of a hygroscopic salt exposed to the atmosphere. The salt absorbs moisture from, or releases moisture to, the atmosphere as a function of the water vapor content of the atmosphere and the temperature to which the salt is heated. Heat is supplied to the hygroscopic salt to a greater or lesser degree in response to changes in the resistivity of the salt and these changes in resistivity are relatively large with relatively small variations in the amount of water absorbed by the salt at its lower percentages of water absorption. The temperature required to maintain the hygroscopic salt at its preselected resistivity and resultant low degree of water content is in direct relationship to the dew point or water vapor content of the atmosphere.
Inventors
👤 Curtis B Campbell
👤 Ben L Grover
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-01 20:23
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/56; G01N25/66
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
72 words
A device for the measurement of water in the atmosphere in a vapor form comprising: a. a hygroscopic salt exposed to the atmosphere; b. heat means for maintaining the electrical resistance of the hygroscopic salt at a selected predetermined value independent of variations of moisture content of said atmosphere from a known moisture content; and c. means for measuring the temperature of said salt required to maintain said resistance of the salt.
Claim 2
Independent Claim
72 words
A device for the measurement of water in the atmosphere in a vapor form comprising: a. a hygroscopic salt exposed to the atmosphere; b. heat means for maintaining the electrical resistance of the hygroscopic salt at a selected predetermined value independent of variations of moisture content of said atmosphere from a known moisture content; and c. means for measuring the temperature of said salt required to maintain said resistance of the salt.
Claim 3
Dependent Claim
15 words
In a device as defined in claim 1 wherein the hygroscopic salt is lithium chloride.
Claim 4
Dependent Claim
62 words
In a device as defined in claim 1 wherein the electrical resistance of the hygroscopic salt is a function of the amount of water absorbed by the salt and including means responsive to change in said predetermined resistance to cause a change in the heat supplied to said salt to thereby return the electrical resistance of said salt to its predetermined state.
Claim 5
Dependent Claim
52 words
In a device as defined in claim 1 wherein the hygroscopic salt is electrically heated to a greater degree under conditions of increased water vapor content in the atmosphere to lower the resultant absorbed water content of the salt sufficiently to return the electrical resistance of the salt to its predetermined resistivity.
Claim 6
Dependent Claim
53 words
In a device as defined in claim 1 wherein the temperature of the heated salt is measured by means of a temperature measuring means in thermal contact with the electrical resistance heater of the salt and said temperature is utilized as an indication of the degree of water vapor present in the atmosphere.
Claim 7
Dependent Claim
36 words
In a device as defined in claim 1 comprising means for maintaining said salt at a temperature wherein the relative humidity of the air at the boundary layer of the salt is less than 11 percent.
Claim 8
Dependent Claim
35 words
In a device for the measurement of water in the atmosphere in a vapor form as defined in claim 1 wherein said electrical resistance of said salt is detected by means of a bifilar winding.
Claim 9
Dependent Claim
39 words
In a device for the measurement of water in the atmosphere in a vapor form as defined in claim 7 wherein natural polarization of said salt is prevented by the use of an alternating current in said bifilar winding.