US4327573A
Expired / Lapsed
US
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Method and apparatus for determining the low temperature characteristics of materials
Assignee: TA Jennings Associates Inc
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Filing: 1980-02-29
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Granted: 1982-05-04
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Expires: 2000-02-29
Abstract
Abstract A method and apparatus for determining the low temperature characteristics of materials measures the resistivity of a sample material and the resistivity of a comparision material and plots the ratio of the resistivity of the comparision material to the resistivity of the sample material versus the temperature of the sample material. In addition, the method and apparatus measures the temperature of the sample and the temperature of a reference material and plots the difference there between as a function of the temperature of the reference material. The method and apparatus is usable in monitoring and/or controlling lyophilization appartus in order to increase the efficiency of the freeze drying process, that is, increasing product yield while reducing processing time.
Inventors
- 👤 Thomas A. Jennings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:42
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/041
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
82 words
A method of determining low temperature characteristics of a sample material comprising the steps of: (a) varying the temperature of said sample material and a comparison material; (b) measuring electrical resistivity of said sample material; (c) measuring electrical resistivity of said comparison material; (d) measuring the temperature of said sample material as a reference temperature; and (e) plotting ratio D 2 of the resistivity of said comparison material to the resistivity of said sample material as a function of said reference temperature.
Claim 2
Independent Claim
82 words
A method of determining low temperature characteristics of a sample material comprising the steps of: (a) varying the temperature of said sample material and a comparison material; (b) measuring electrical resistivity of said sample material; (c) measuring electrical resistivity of said comparison material; (d) measuring the temperature of said sample material as a reference temperature; and (e) plotting ratio D 2 of the resistivity of said comparison material to the resistivity of said sample material as a function of said reference temperature.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein step (d) comprises measuring the temperature T s of said sample material.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein step (d) comprises measuring the temperature of said comparison material.
Claim 5
Dependent Claim
43 words
The method of claim 2 or claim 3 wherein step (a) further comprises the steps of cooling said sample material and said comparison material to a first pre-determined temperature below the freezing points thereof then warming said materials to a second pre-determined temperature.
Claim 6
Dependent Claim
24 words
The method of claim 4 wherein said sample material is a water containing material and step (c) comprises measuring the electrical resistivity of ice.
Claim 7
Dependent Claim
59 words
The method of claim 5 wherein step (a) comprises varying the temperature of said sample material, said comparison material and a reference material, and comprising the additional steps of: (f) measuring the temperature T R of said reference material; and (g) plotting the difference ΔT DTA of T S minus T R as a function of T R .
Claim 8
Dependent Claim
16 words
The method of claim 6 wherein step (f) comprises measuring the temperature T R of Methanol.
Claim 9
Independent Claim
90 words
An apparatus for determining low temperature characteristics of a sample material comprising: (a) means for varying the temperature of said sample material and a comparison material; (b) means for measuring electrical resistivity of said sample material; (c) means for measuring electrical resistivity of said comparison material; (d) means for measuring the temperature of said sample material as a reference temperature; and (e) means for plotting a ratio D 2 of the resistivity of said comparison material to the resistivity of said sample material as a function of said reference temperature.
Claim 10
Independent Claim
90 words
An apparatus for determining low temperature characteristics of a sample material comprising: (a) means for varying the temperature of said sample material and a comparison material; (b) means for measuring electrical resistivity of said sample material; (c) means for measuring electrical resistivity of said comparison material; (d) means for measuring the temperature of said sample material as a reference temperature; and (e) means for plotting a ratio D 2 of the resistivity of said comparison material to the resistivity of said sample material as a function of said reference temperature.
Claim 11
Dependent Claim
28 words
The apparatus in accordance with claim 8 wherein said means for measuring the electrical resistivity of said sample material comprises a resistivity cell having an adjustable cell constant.
Claim 12
Dependent Claim
28 words
The apparatus in accordance with claim 9 wherein said means for measuring the electrical resistivity of said comparison material comprises a resistivity cell having an adjustable cell constant.
Claim 13
Dependent Claim
93 words
The apparatus in accordance with claim 10 wherein said means for plotting the ratio D 2 comprises computer means for accepting the measurement of the electrical resistivity of said sample material, accepting the measurement of the electrical resistivity of said comparison material, providing an output which is a function of the value of the ratio of the latter measurement to the former measurement, and data display means for accepting the output of said computer means and the measurement of said reference temperature and providing a visual display of the functional relationship there between.
Claim 14
Dependent Claim
16 words
The apparatus in accordance with claim 11 wherein said data display means comprises an X-Y recorder.
Claim 15
Dependent Claim
16 words
The invention of claim 11 wherein said data display means comprises a Cathode Ray Tube Terminal.
Claim 16
Dependent Claim
16 words
The apparatus in accordance with claim 11 wherein said data display means comprises a digital printer.
Claim 17
Independent Claim
138 words
An apparatus for determining low temperature characteristics of a sample material comprising: (a) means for varying the temperature of said sample material, a comparison material, and a reference material; (b) means for measuring electrical resistivity of said sample material; (c) means for measuring electrical resistivity of said comparison material; (d) means for measuring the temperature of said sample material as a reference temperature; (e) means for plotting a ratio D 2 of the resistivity of said comparison material to the resistivity of said sample material as a function of said reference temperature; (f) means for measuring the temperature T s of said sample material; (g) means for measuring the temperature T R of said reference material; and (h) means for plotting the difference ΔT DTA of T S minus T R as a function of T R .
Claim 18
Independent Claim
138 words
An apparatus for determining low temperature characteristics of a sample material comprising: (a) means for varying the temperature of said sample material, a comparison material, and a reference material; (b) means for measuring electrical resistivity of said sample material; (c) means for measuring electrical resistivity of said comparison material; (d) means for measuring the temperature of said sample material as a reference temperature; (e) means for plotting a ratio D 2 of the resistivity of said comparison material to the resistivity of said sample material as a function of said reference temperature; (f) means for measuring the temperature T s of said sample material; (g) means for measuring the temperature T R of said reference material; and (h) means for plotting the difference ΔT DTA of T S minus T R as a function of T R .
Claim 19
Dependent Claim
28 words
An apparatus in accordance with claim 15 wherein said means for measuring the electrical resistivity of said sample material comprises a resistivity cell having an adjustable cell constant.
Claim 20
Dependent Claim
28 words
The apparatus in accordance with claim 16 wherein said means for measuring the electrical resistivity of said comparison material comprises a resistivity cell having an adjustable cell constant.
Claim 21
Dependent Claim
93 words
The apparatus in accordance with claim 17 wherein said means for plotting the ratio D 2 comprises computer means for accepting the measurement of the electrical resistivity of said sample material, accepting the measurement of the electrical resistivty of said comparison material, providing an output which is a function of the value of the ratio of the latter measurement to the former measurement, and data display means for accepting the output of said computer means and the measurement of said reference temperature and providing a visual display of the functional relationship there between.
Claim 22
Dependent Claim
73 words
The apparatus in accordance with claim 18 wherein said means for plotting the difference ΔT DTA of T S minus T R as a function of T R comprises data display means for accepting a signal which is a function of the value of the quantity T S minus T R as well as the measurement of said reference temperature T R and providing a visual display of the functional relationship there between.
Claim 23
Dependent Claim
18 words
The apparatus in accordance with claim 19 wherein said data display means comprises a dual channel X-Y recorder.
Claim 24
Dependent Claim
16 words
The invention of claim 20 wherein said data display means comprises a Cathode Ray Tube Terminal.
Claim 25
Dependent Claim
16 words
The apparatus in accordance with claim 21 wherein said data display means comprises a digital printer.
Claim 26
Independent Claim
176 words
An apparatus for controlling or monitoring a freeze drying operation on water--containing solid substance for the preservation of said substances, said apparatus comprising: (a) means for varying the temperature of said water--containing solid substance, ice, and a reference material; (b) means for measuring electrical resistivity of said water--containing solid substance; (c) means for measuring electrical resistivity of said ice; (d) means for measuring the temperature T S of said water--containing solid substance; (e) means for providing a first signal, the magnitude of which is a function of the magnitude of the ratio D 2 of the resistivity of said ice to the resistivity of said water--containing solid substance; (f) means for providing a controlled signal when the magnitude of said first signal has reached a pre-determined value; (g) means for plotting D 2 as a function of said temperature T S ; and (h) means for measuring the temperature T R of said reference material; and means for plotting the difference ΔT DTA of T S minus T R as a function of T R .
Claim 27
Independent Claim
176 words
An apparatus for controlling or monitoring a freeze drying operation on water--containing solid substance for the preservation of said substances, said apparatus comprising: (a) means for varying the temperature of said water--containing solid substance, ice, and a reference material; (b) means for measuring electrical resistivity of said water--containing solid substance; (c) means for measuring electrical resistivity of said ice; (d) means for measuring the temperature T S of said water--containing solid substance; (e) means for providing a first signal, the magnitude of which is a function of the magnitude of the ratio D 2 of the resistivity of said ice to the resistivity of said water--containing solid substance; (f) means for providing a controlled signal when the magnitude of said first signal has reached a pre-determined value; (g) means for plotting D 2 as a function of said temperature T S ; and (h) means for measuring the temperature T R of said reference material; and means for plotting the difference ΔT DTA of T S minus T R as a function of T R .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-03 | 1985-11-02 | 1986-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-03 | 1989-11-02 | 1990-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-03 | 1993-11-02 | 1994-05-04 | $7700.00 | Window Closed / Lapsed |