US4352059A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination of moisture level in materials
Assignee: Massachusetts Institute of Technology
•
Filing: 1980-06-13
•
Granted: 1982-09-28
•
Expires: 2000-06-13
Abstract
Abstract A method for determining the moisture content of dielectric materials is described wherein a sample of the material is placed between two electrodes and an electric field is applied. An alternating frequency in the range of radio waves and lower is applied to the electrodes and the dielectric loss properties of the material are determined. The dielectric loss properties are then used to determine moisture content. In an alternate embodiment, a step voltage is applied to the electrodes and the direct current is monitored. The decrease in value of direct current during a time interval following the application of the step voltage is used to determine the moisture content.
Inventors
- 👤 Nam P. Suh
- 👤 Stephen D. Senturia
- 👤 Byung H. Kim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:13
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/223; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2617; G01R27/2635; G01R27/2647
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
57 words
A method for determining the moisture content of solid dielectric materials comprises placing a sample of said material between two electrodes, applying an alternating electric field having a frequency in the range of radio waves to said electrodes, determining the dielectric loss properties of said material, and using the dielectric loss properties to determine the moisture content.
Claim 2
Independent Claim
57 words
A method for determining the moisture content of solid dielectric materials comprises placing a sample of said material between two electrodes, applying an alternating electric field having a frequency in the range of radio waves to said electrodes, determining the dielectric loss properties of said material, and using the dielectric loss properties to determine the moisture content.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein said material is a polymer.
Claim 4
Dependent Claim
14 words
The method of claim 2 wherein said polymer is in the form of granules.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said frequency is the frequency of maximum dielectric loss for said material.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein said material is a nylon and said frequency is about 20,000 Hz.
Claim 7
Dependent Claim
25 words
The method of claim 1 wherein said material is a polyamide and the frequency is on the order of magnitude of about 10 4 Hz.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein said material is a poly(amide-imide) and the frequency is on the order of magnitude of about 10 5 Hz.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein said material is a polyethylene terephthalate and the frequency is on the order of magnitude of about 10 5 Hz.
Claim 10
Dependent Claim
25 words
The method of claim 1 wherein said material is a polycarbonate and the frequency is on the order of magnitude of about 10 7 Hz.
Claim 11
Dependent Claim
25 words
The method of claim 1 wherein said material is a polymethylmethacrylate and the frequency is on the order of magnitude of about 10 5 Hz.
Claim 12
Dependent Claim
26 words
The method of claim 1 wherein said material is a thermoplastic polyurethane and the frequency is on the order of magnitude of about 10 3 Hz.
Claim 13
Dependent Claim
15 words
The method of claim 1 wherein said material contains a substantial amount of bound water.
Claim 14
Dependent Claim
15 words
The method of claim 1 wherein said dielectric loss property is the dielectric loss factor.
Claim 15
Dependent Claim
15 words
The method of claim 1 wherein said dielectric loss property is the dielectric loss tangent.
Claim 16
Independent Claim
53 words
A method for determining the moisture content of a solid dielectric material comprises placing a sample of said material between two electrodes, applying an alternating electric field having a frequency of about 100,000 Hz or less to said electrodes, and measuring the dielectric loss properties of said material to determine the moisture content.
Claim 17
Independent Claim
53 words
A method for determining the moisture content of a solid dielectric material comprises placing a sample of said material between two electrodes, applying an alternating electric field having a frequency of about 100,000 Hz or less to said electrodes, and measuring the dielectric loss properties of said material to determine the moisture content.
Claim 18
Independent Claim
229 words
A method for determining whether the moisture content of a sample of solid dielectric material is within an acceptable predetermined range of moisture content, said method comprising: connecting a first standard sample of said material having a known predetermined minimum moisture content to one leg of the bridge of an impedance comparator having a phase angle difference meter and an impedance difference meter, applying an alternating electric field having a frequency in the range of radio waves to said first standard sample, and nulling the phase angle difference meter and the impedance difference meter to obtain a first set of dial readings; connecting a second standard sample of said material having a known predetermined maximum moisture content to the leg of the bridge, applying the alternating electric field having said frequency to said second standard sample, and nulling the meters to obtain a second set of dial readings; thus, calibrating the impedance comparator; connecting a sample of said material having an unknown moisture content to the leg of the bridge, applying the alternating current at said frequency, and nulling the meters to obtain a third set of dial readings; and comparing the third set of dial readings with the first and second sets of dial readings to determine whether the moisture content of said sample having unknown moisture content is between the moisture content of the two standard samples.
Claim 19
Independent Claim
229 words
A method for determining whether the moisture content of a sample of solid dielectric material is within an acceptable predetermined range of moisture content, said method comprising: connecting a first standard sample of said material having a known predetermined minimum moisture content to one leg of the bridge of an impedance comparator having a phase angle difference meter and an impedance difference meter, applying an alternating electric field having a frequency in the range of radio waves to said first standard sample, and nulling the phase angle difference meter and the impedance difference meter to obtain a first set of dial readings; connecting a second standard sample of said material having a known predetermined maximum moisture content to the leg of the bridge, applying the alternating electric field having said frequency to said second standard sample, and nulling the meters to obtain a second set of dial readings; thus, calibrating the impedance comparator; connecting a sample of said material having an unknown moisture content to the leg of the bridge, applying the alternating current at said frequency, and nulling the meters to obtain a third set of dial readings; and comparing the third set of dial readings with the first and second sets of dial readings to determine whether the moisture content of said sample having unknown moisture content is between the moisture content of the two standard samples.
Claim 20
Independent Claim
67 words
A method for determining the moisture content of a dielectric material comprising placing a sample of said material between two electrodes, subjecting the material to a step voltage, determining the value of direct current in said material at a preselected time interval after said step voltage is applied, and determining the moisture content of said material using the value of the direct current at said preselected time.
Claim 21
Independent Claim
67 words
A method for determining the moisture content of a dielectric material comprising placing a sample of said material between two electrodes, subjecting the material to a step voltage, determining the value of direct current in said material at a preselected time interval after said step voltage is applied, and determining the moisture content of said material using the value of the direct current at said preselected time.
Claim 22
Dependent Claim
11 words
The method of claim 17 wherein said material is a polymer.
Claim 23
Dependent Claim
18 words
The method of claim 17 wherein said step voltage is less than the breakdown voltage of the material.
References Cited (Backward Citations)
US3252086A
Cited
US3657644A
Cited
US3684952A
Cited
US3778707A
Cited
US4109033A
Cited
US4097743A
Cited
DE2851686A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-27 | 1986-03-29 | 1986-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-27 | 1990-03-29 | 1990-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-27 | 1994-03-29 | 1994-09-28 | $7700.00 | Window Closed / Lapsed |