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Method and apparatus for measuring the density of fluids

  • US 4,956,793 A
  • Filed: 06/24/1988
  • Issued: 09/11/1990
  • Est. Priority Date: 06/24/1988
  • Status: Expired due to Fees
First Claim
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1. Apparatus for determining specific gravity, ρ

  • , of a fluid of interest comprising;

    electrical resistance heater means;

    thermal sensor means in proximate position to said heater means and in thermal communication therewith through the fluid of interest, the thermal sensor means having an output dependent on thermal sensor temperature;

    adjustable electrical energizing means connected to said heater means for energizing said heater means on a time and level-variable pulse basis in a manner to induce both transient and substantially steady-state elevated temperature condition intervals in said thermal sensor means;

    means for adjusting level and duration of the output of the adjustable electrical energizing means;

    first output means for providing a first output signal indicative of a temperature of said thermal sensor means;

    timing means for determining a rate of change of temperature of said temperature sensor during a transient temperature interval based on time variation of said first output signal between at least two known values;

    means for determining k of the fluid of interest based upon said first output signal at steady-state elevated sensor temperature; and

    means for determining cp, of the fluid of interest based on k and the rate of change of the first output signal during a transient temperature condition;

    means for producing signals indicative of the values of k and cp of the fluid of interest;

    conversion means for converting signals indicative of the values of k and cp of the fluid of interest to values indicative of ρ

    of the fluid of interest.

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