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US 4,359,285 AGranted
Temperature measurement system
AssigneeSippican, Inc.
InventorRalph G. Washburn
Life of this patent
Estimating the term…
Abstract
In a temperature probe having a thermistor controlling the output frequency of an oscillator to effect a temperature-frequency conversion, and a remote measuring station having a frequency detection means, the invention features, generally, a switch in the probe connected to a detection circuit, the oscillator being connected to the switch so as to open and close the circuit in response to the oscillator output frequency.
Claims12
A system for remote measurement of a physical parameter comprising:
- a measuring station,
- a portable probe adapted to be deployed remotely from said measuring station,
- a power circuit connected between said probe and said measuring station,
- a detection circuit connected between said measuring station and said probe,
- said power circuit and said detection circuit having at least one wire at least 2500 feet long connecting said probe to said measuring station,
- said measuring station having
- a power source connected in said power circuit and in said detection circuit, and
- detecting means connected in said detection circuit for determining whether said detection circuit is open or closed,
- said probe having
- an element for sensing said parameter,
- a variable frequency oscillator connectod to said power circuit and to said element to provide an alternating current output at a frequency dependent upon the condition of said element, and
- switch means connected in said detection circuit and to said oscillator to open and close at a rate dependent upon said frequency so that said parameter can be effectively measured at said measuring station without transmission of said alternating current output over said detection circuit.
9 more elements
Dependencies are inferred from the claim text.