Temperature correction systems for a fluid flow meter

Abstract

A conventional fluid flow meter provides a single pulse output signal for each uncorrected unit volume flow. A monostable multivibrator (MV) is triggered by said meter signal and provides a gating signal for a 1 MHZ oscillator to produce a pulse train. A temperature sensor senses the fluid flow at the meter and controls the monostable MV so that the number of pulses in said pulse train is inversely proportional to the absolute temperature of the fluid flow. A preset down counter derives from said pulse train a number representing the absolute temperature at the sensor. A burst generator generates a fixed number of pulses related to a predetermined base temperature. A divider divides said fixed number of pulses by said number representing the absolute temperature of the fluid flow and provides a single pulse output for each integer resulting from said division and stores the remainder from said division for use in the next division. A register accumulates the number of pulses resulting from said division and represents the corrected volume flow. The above calculation is completed in a small fraction of the time period between meter pulses. A solid state switch operates to supply power to said monostable MV and to enable said oscillator for a preset time period sufficient to permit said calculation to be completed. The switch then turns off the power supply and disables the oscillator until the next meter pulse occurs.