US3672205A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination of heat transfer through fluids
Assignee: United States Department of the Air Force
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Filing: 1970-12-14
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Granted: 1972-06-27
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Expires: 1990-12-14
Abstract
Abstract A method is provided for determining the heat transfer properties of a fluid which comprises filling the space between two concentric geometrically similar objects with the fluid to be tested, the objects being in a state of thermal equilibrium; changing the temperature of the outer of the two concentric bodies; measuring the capacitance between the bodies as the temperature of the outer body changes; and measuring the time required for the capacitance measurement to reach a constant value, thereby indicating that the two bodies are in a new state of thermal equilibrium. One of the most important uses of the method is in controlling the quality of industrial products produced by continuous processes.
Inventors
- 👤 Wolfgang Leidenfrost
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:22
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A method for determining the heat transfer properties of a fluid which comprises the steps of filling the space between an outer conductive body and an inner conductive body, which are geometrically similar and concentrically positioned, with the fluid to be tested, said bodies being initially maintained in a state of thermal equilibrium at a constant predetermined temperature; changing the temperature of said outer body by a constant transfer of heat to a new constant predetermined temperature; maintaining said outer body at said new temperature; measuring the capacitance between said bodies as a function of time as the temperature of said outer body changes and while maintaining said outer body at said new temperature; and measuring the time required for the capacitance measurement to reach a constant value, thereby indicating that said inner and outer bodies are in a new state of thermal equilibrium at said new constant predetermined temperature.
Claim 2
Independent Claim
150 words
A method for determining the heat transfer properties of a fluid which comprises the steps of filling the space between an outer conductive body and an inner conductive body, which are geometrically similar and concentrically positioned, with the fluid to be tested, said bodies being initially maintained in a state of thermal equilibrium at a constant predetermined temperature; changing the temperature of said outer body by a constant transfer of heat to a new constant predetermined temperature; maintaining said outer body at said new temperature; measuring the capacitance between said bodies as a function of time as the temperature of said outer body changes and while maintaining said outer body at said new temperature; and measuring the time required for the capacitance measurement to reach a constant value, thereby indicating that said inner and outer bodies are in a new state of thermal equilibrium at said new constant predetermined temperature.
Claim 3
Dependent Claim
47 words
A method according to claim 1 in which the temperature of said outer body is changed by heating said body at a constant heat input to said new constant predetermined temperature and the heating is thereafter controlled so as to maintain said body at said new temperature.
Claim 4
Independent Claim
341 words
A method for use in controlling the quality of a fluid product which comprises the steps of filling the space between an outer conductive body and an inner conductive body, which are geometrically similar and concentrically positioned, with a fluid product of desired quality, said bodies being initially maintained in a state of thermal equilibrium at a predetermined initial temperature at least as high as the temperature of said product; heating said outer body at a constant heat input to a new predetermined higher temperature; controlling the heating of said outer body so as to maintain said body at said new temperature; measuring the capacitance between said bodies as a function of time as the temperature of said outer body changes and while maintaining said outer body at said new temperature; continuing to measure the capacitance between said bodies until said capacitance measurement remains constant, thereby indicating that said inner and outer bodies are in a new state of thermal equilibrium at said new predetermined higher temperature; withdrawing said fluid product of desired quality from said space; filling said space between said bodies with a fluid of unknown quality, said fluid being a product of the same process as the fluid product of desired quality, said bodies being in a state of thermal equilibrium at said predetermined initial temperature; heating said outer body at a constant heat input to said new predetermined higher temperature; controlling the heating of said outer body so as to maintain said body at said new temperature; measuring the capacitance between said bodies as a function of time as the temperature of said outer body changes and while maintaining said outer body at said new temperature; continuing to measure the capacitance between said bodies until said capacitance measurement remains constant, thereby indicating that said inner and outer bodies are in a new state of thermal equilibrium at said new predetermined higher temperature; and comparing the capacitance measurements obtained with said fluid product of desired quality with the capacitance measurements obtained with said fluid product of unknown quality.
Claim 5
Independent Claim
341 words
A method for use in controlling the quality of a fluid product which comprises the steps of filling the space between an outer conductive body and an inner conductive body, which are geometrically similar and concentrically positioned, with a fluid product of desired quality, said bodies being initially maintained in a state of thermal equilibrium at a predetermined initial temperature at least as high as the temperature of said product; heating said outer body at a constant heat input to a new predetermined higher temperature; controlling the heating of said outer body so as to maintain said body at said new temperature; measuring the capacitance between said bodies as a function of time as the temperature of said outer body changes and while maintaining said outer body at said new temperature; continuing to measure the capacitance between said bodies until said capacitance measurement remains constant, thereby indicating that said inner and outer bodies are in a new state of thermal equilibrium at said new predetermined higher temperature; withdrawing said fluid product of desired quality from said space; filling said space between said bodies with a fluid of unknown quality, said fluid being a product of the same process as the fluid product of desired quality, said bodies being in a state of thermal equilibrium at said predetermined initial temperature; heating said outer body at a constant heat input to said new predetermined higher temperature; controlling the heating of said outer body so as to maintain said body at said new temperature; measuring the capacitance between said bodies as a function of time as the temperature of said outer body changes and while maintaining said outer body at said new temperature; continuing to measure the capacitance between said bodies until said capacitance measurement remains constant, thereby indicating that said inner and outer bodies are in a new state of thermal equilibrium at said new predetermined higher temperature; and comparing the capacitance measurements obtained with said fluid product of desired quality with the capacitance measurements obtained with said fluid product of unknown quality.
Claim 6
Independent Claim
163 words
An apparatus for determining the heat transfer properties of fluids which comprises an inner conductive body and an outer conductive body, said bodies being geometrically similar and concentrically positioned in spaced-apart relationship with respect to one another so as to provide a space therebetween; means for centering said inner body within said outer body; means for introducing fluid into said space between said bodies; means for withdrawing fluid from said space between said bodies; heat exchange means associated with said outer body for transferring heat by a constant known amount and including means substantially confining the resultant heat flow between said inner and outer bodies; means for controlling the temperature of said outer body including means to maintain said outer body at a predetermined temperature when said temperature is reached as a result of heat transfer; means for continuously measuring capacitance as a function of time; and a pair of electrical leads connecting said inner and outer bodies to said capacitance measuring means.
Claim 7
Independent Claim
163 words
An apparatus for determining the heat transfer properties of fluids which comprises an inner conductive body and an outer conductive body, said bodies being geometrically similar and concentrically positioned in spaced-apart relationship with respect to one another so as to provide a space therebetween; means for centering said inner body within said outer body; means for introducing fluid into said space between said bodies; means for withdrawing fluid from said space between said bodies; heat exchange means associated with said outer body for transferring heat by a constant known amount and including means substantially confining the resultant heat flow between said inner and outer bodies; means for controlling the temperature of said outer body including means to maintain said outer body at a predetermined temperature when said temperature is reached as a result of heat transfer; means for continuously measuring capacitance as a function of time; and a pair of electrical leads connecting said inner and outer bodies to said capacitance measuring means.
Claim 8
Dependent Claim
25 words
An apparatus according to claim 4 in which said inner body is a solid metallic sphere and said outer body is a metallic, spherical shell.
Claim 9
Dependent Claim
68 words
An apparatus according to claim 5 in which said outer body is covered with a first insulating material; said heat exchange means is a heating coil wound around said first insulating material and covered with a second insulating material and having its ends connected to a constant power source; and said constant power source is operatively connected to said means foR controlling the temperature of said outer body.
Claim 10
Dependent Claim
34 words
An apparatus according to claim 6 in which said capacitance measuring means is a capacitance bridge and said capacitance bridge is connected to a means for recording capacitance measurements as a function of time.
Claim 11
Dependent Claim
101 words
An apparatus according to claim 7 in which said constant power source is a battery; a first electrical lead connects the positive terminal of said battery to one end of said heating coil; a second electrical lead connects the negative terminal of said battery to the other end of said heating coil; and a switch is positioned in said first electrical lead. 9 An apparatus according to claim 8 in which said means for controlling the temperature of said outer body is a temperature controller operatively connected to said second electrical lead and to a thermistor embedded in said outer body.
Claim 12
Dependent Claim
115 words
An apparatus according to claim 9 in which said means for introducing fluid into said space between said bodies is an inlet line having one of its ends connected to a first opening in said outer body to said space and its other end connected to a fluid product conduct; a valve is positioned in said inlet line, said valve being operatively connected to said switch positioned in said first electrical lead; and said means for withdrawing fluid from said space between said bodies is an outlet line having one of its ends connected to a second opening in said outer body to said space and its other end connected to said fluid product conduit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |