Patent ID: 6367306
Filing Date: 2002-04-09
Classification: G01F

Abstract:
An instrumental error compensation apparatus for a fluid flow measuring instrument comprising:a positive displacement flowmeter having a rotor and inlet and outlet means for measuring the flow rate of fluid flowing therethrough; temperature sensor means mounted on said flowmeter for measuring the temperature of the fluid flowing through the flowmeter and for producing an electrical signal representing the measured temperature; rotation sensor means mounted on said flowmeter for measuring the rotation speed of said rotor and for producing an electrical pulse signal representing the measured rotation speed; microprocessor control unit means for receiving said electrical pulse signals from said temperature and rotation sensor means; electric pulse signal conducting means for operatively connecting said temperature and rotation sensor means to said control unit means for conducting said signals from said temperature and rotation sensor means to said microprocessor control unit means; said microprocessor control unit means including means for correlating the viscosity of the fluid as a function of the measured temperature with instrumental error and storing correlated temperature-viscosity data; means for determining the period of pulse signals transmitted for each rotation of said rotor, and means for calculating a compensation value from the instrumental error compensation data based on the correlated temperature-viscosity data stored in said microprocessor control unit means; means for calculating a first flow rate from said electrical pulse signal representing measured rotation speed and modifying said first flow rate by said compensation value to procure a second flow rate; means for outputting and indicating said second flow rate in real time; a compensating characteristic errors ROM for storing compensating characteristic errors specific to the flowmeter; means for making instrumental error compensations based on fluid volumetric changes and correlation of temperature viscosity; means for feeding said instrumental errors to said microprocessor control unit; and a magnet sensor and temperature sensor connected to an input/output interface for calculating a flow rate.