US3634841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature and salinity indicating and/or control apparatus
Assignee: Findlay Irvine Ltd
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Filing: 1969-10-08
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Granted: 1972-01-11
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Expires: 1989-10-08
Abstract
Abstract Apparatus for use in indicating and/or controlling the temperature of a road or like surface in the presence of ice includes a temperature-sensitive transistor mounted on or in the surface and arranged in the presence of a first bias voltage to generate a predetermined output signal when the temperature of the device falls to near 0* C. A conductivity detector is arranged to detect the presence of moisture of an electrical conductivity exceeding a predetermined conductivity and to trigger a bistable to apply a second bias voltage to the transistor. In the presence of the second bias voltage the transistor generates the predetermined output signal only when the temperature of the transistor falls to a predetermined temperature below 0* C. Thus if the surface has been covered with salt the indication or heating is inhibited until the temperature has fallen to the predetermined temperature below 0* C.
Inventors
- 👤 John Anderson Irvine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:41
CPC Classifications
G; G01; G01K; G01K3/00; G01K3/005; G01W; G01W1/00; G01W1/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
226 words
A surface-ice-sensing system comprising: a surface; a temperature-sensitive semiconductor device in said surface having a control terminal and an output terminal, the output signal developed at said output terminal being dependent upon the signal applied to said control terminal and upon the temperature of said device; first biasing means coupled to said control terminal of said device to apply a first biasing signal to said control terminal of said device, said first biasing signal being of a magnitude such that said output signal developed at said output terminal of said device reaches a preset level when said device is at around 0* C.; a conductivity detector in said surface to measure the conductivity of moisture on said surface; second biasing means coupled between said conductivity detector and said semiconductor device to apply a second biasing signal to said control terminal of said device when said conductivity detector detects a conductivity in excess of a predetermined conductivity, said second biasing signal being of a magnitude such that said output signal developed at said output terminal of said device reaches said preset level only when said device is at a predetermined temperature below 0* C. whereby in the presence of moisture on said surface having a conductivity exceeding said predetermined conductivity, generation of said output signal is inhibited until said device reaches said predetermined temperature below 0* C.
Claim 2
Dependent Claim
226 words
A surface-ice-sensing system comprising: a surface; a temperature-sensitive semiconductor device in said surface having a control terminal and an output terminal, the output signal developed at said output terminal being dependent upon the signal applied to said control terminal and upon the temperature of said device; first biasing means coupled to said control terminal of said device to apply a first biasing signal to said control terminal of said device, said first biasing signal being of a magnitude such that said output signal developed at said output terminal of said device reaches a preset level when said device is at around 0* C.; a conductivity detector in said surface to measure the conductivity of moisture on said surface; second biasing means coupled between said conductivity detector and said semiconductor device to apply a second biasing signal to said control terminal of said device when said conductivity detector detects a conductivity in excess of a predetermined conductivity, said second biasing signal being of a magnitude such that said output signal developed at said output terminal of said device reaches said preset level only when said device is at a predetermined temperature below 0* C. whereby in the presence of moisture on said surface having a conductivity exceeding said predetermined conductivity, generation of said output signal is inhibited until said device reaches said predetermined temperature below 0* C.
Claim 3
Dependent Claim
16 words
Apparatus as claimed in claim 1, wherein said detector is adjustable to vary said predetermined conductivity.
Claim 4
Dependent Claim
19 words
Apparatus as claimed in claim 1, wherein said second biasing means comprises a bistable circuit operative as a switch.
Claim 5
Dependent Claim
39 words
Apparatus as claimed in claim 3, wherein said first biasing means comprise a voltage divider connecting a source of biasing voltage to said control terminal of said device, and said bistable circuit is connected to vary said voltage divider.
Claim 6
Dependent Claim
13 words
Apparatus as claimed in claim 1, wherein said detector comprises two spaced electrodes.
Claim 7
Dependent Claim
32 words
Apparatus as claimed in claim 5, wherein said detector further comprises a source of alternating current, and the primary winding of a transformer connected in series with said electrodes across said source.
Claim 8
Dependent Claim
17 words
Apparatus as claimed in claim 6, comprising a rectifier connected to a secondary winding of said transformer.
Claim 9
Dependent Claim
17 words
Apparatus as claimed in claim 1 comprising an indicator connected to said output terminal of said device.
Claim 10
Dependent Claim
17 words
Apparatus as claimed in claim 1 comprising a heater connected to said output terminal of said device.
Claim 11
Dependent Claim
112 words
Apparatus as claimed in claim 1 wherein said device comprises a transistor, said first biasing means comprises a variable potential divider the tap of which is connected to the control electrode of said transistor, said detector comprises two spaced electrodes, a source of alternating current in series with said electrodes, a primary winding of a transformer connected across said electrodes and said source, variable resistance means connected across said primary winding, and rectifying and smoothing means connected to a secondary winding of said transformer, and said second biasing means comprises a bistable circuit operative as a switch and connected to said potential divider to vary the effective resistance of one part thereof.
References Cited (Backward Citations)
US3197699A
Cited
US3469250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |