US3690177A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermocouple reference junction
Assignee: Applied Automation Inc
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Filing: 1970-11-16
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Granted: 1972-09-12
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Expires: 1990-11-16
Abstract
Abstract Reference thermocouple junctions are maintained at a constant temperature by an insulated housing which surrounds the junctions. A heating element is contained within the housing. Temperature sensing elements disposed within and outside the housing control the heating element. The thermocouple junctions, internal sensing element and heating element can be secured to a metal block within the housing.
Inventors
- 👤 Dale A Fluegel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:29
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/02; G01K7/10; G01K7/12; G01N; G01N25/00; G01N25/18
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
146 words
In a temperature measuring system which includes a thermocouple having at least one temperature sensing junction and at least one reference temperature junction; apparatus for maintaining the reference junction at a constant temperature comprising: a housing enclosing said reference junction; a heating element disposed in said housing in thermal contact with said reference junction; a first thermistor disposed in said housing in thermal contact with said reference junction; a second thermistor positioned externally of said housing and in close proximity thereto; a bridge network having a source of potential connected thereacross, said first and second thermistors being connected in series relationship in one arm of said bridge network: means responsive to any electrical unbalance of said bridge network to establish a control signal which is representative of the combined temperatures sensed by said thermistors; and means responsive to said control signal to regulate said heating element.
Claim 2
Dependent Claim
146 words
In a temperature measuring system which includes a thermocouple having at least one temperature sensing junction and at least one reference temperature junction; apparatus for maintaining the reference junction at a constant temperature comprising: a housing enclosing said reference junction; a heating element disposed in said housing in thermal contact with said reference junction; a first thermistor disposed in said housing in thermal contact with said reference junction; a second thermistor positioned externally of said housing and in close proximity thereto; a bridge network having a source of potential connected thereacross, said first and second thermistors being connected in series relationship in one arm of said bridge network: means responsive to any electrical unbalance of said bridge network to establish a control signal which is representative of the combined temperatures sensed by said thermistors; and means responsive to said control signal to regulate said heating element.
Claim 3
Dependent Claim
34 words
The apparatus of claim 1 wherein said reference junction comprises two thermocouple junctions, and further comprising circuit means connecting the temperature sensing junction of said thermocouple in series relationship between said two reference junctions.
Claim 4
Dependent Claim
162 words
In a temperature measuring system which includes a thermocouple having at least one temperature sensing junction and at least one reference temperature junction; apparatus for maintaining the reference junction at a constant temperature comprising: a metal block surrounded by a mass of heat insulating material, said block having a plurality of openings therein, said reference junction being disposed in a first one of said openings in thermal contact with said block; a heating element disposed in a second one of said openings in thermal contact with said block; a first temperature sensing element disposed in a third one of said openings in thermal contact with said block; a second temperature sensing g element externally of said heat insulating material and in close proximity thereto; means responsive to said first and second temperature sensing elements to establish a control signal which is representative of the combined temperatures sensed by said elements; and means responsive to said control signal to regulate said heating element.
Claim 5
Dependent Claim
162 words
In a temperature measuring system which includes a thermocouple having at least one temperature sensing junction and at least one reference temperature junction; apparatus for maintaining the reference junction at a constant temperature comprising: a metal block surrounded by a mass of heat insulating material, said block having a plurality of openings therein, said reference junction being disposed in a first one of said openings in thermal contact with said block; a heating element disposed in a second one of said openings in thermal contact with said block; a first temperature sensing element disposed in a third one of said openings in thermal contact with said block; a second temperature sensing g element externally of said heat insulating material and in close proximity thereto; means responsive to said first and second temperature sensing elements to establish a control signal which is representative of the combined temperatures sensed by said elements; and means responsive to said control signal to regulate said heating element.
Claim 6
Dependent Claim
29 words
The apparatus of claim 7 wherein said block has additional openings through which electrical leads extending to said reference junction pass prior to being connected to said reference junction.
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) | 1975-09-12 | 1976-03-13 | 1976-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-12 | 1980-03-13 | 1980-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-12 | 1984-03-13 | 1984-09-12 | $7700.00 | Window Closed / Lapsed |