Environmental condition sensing apparatus
US3968691A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 13, 1974 |
| Grant date | Jul 13, 1976 |
| Priority date | — |
| Expiry date | Mar 13, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/282
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A Bourdon tube is situated down hole in an oil well or the like, and has attached thereto a coded wheel which rotates an amount determined by the sensed down hole pressure. The wheel has a number of transparent and opaque concentric bands thereon which form a gray code pattern indicative of a selected range of pressures. A plurality of radiant energy transmitters are radially positioned on one side of the wheel in optical alignment with each of the respective bands. A plurality of radiant energy sensors are positioned and aligned in a like manner on the other side of the wheel for sensing the passing or blocking of the radiant energy by the respective bands formed on the wheel. Included is a digital logic circuit controlled by a temperature responsive oscillator which provides timing signals having a frequency determined by the sensed down hole temperature. The logic circuit responds to the signals sensed by the sensors for providing a binary coded output signal indicative of the sensed down hole pressure and temperature, wherein the sequence of the bits in the signal is indicative of the pressure and the frequency of the signal is indicative of the temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.