ALGORITHM FOR TEMPERATURE CORRECTION OF VIBRATION DENSITY METERS
Keywords:
Vibrations transducer, density meter, additional temperature measurement error, thermal compensation algorithm, comparator fluid, calibration coefficientsAbstract
In this article additional temperature error of vibration density meters in liquids and gases
is reviewed. Particularly scrutinized are the effects of change in the temperature of the medium
on the vibration frequency of the density vibration transducers. Main principle of operation
and advantages of vibration density meters is described. The article analyzes and describes the
existing algorithms of calculating density and active temperature compensation as well as the
disadvantages of those algorithms. It points out to the significant limitations of temperature
calibration diapason of the existing methods which relate to the necessity of using distilled water.
Basing on the previous vibration transducer simulation and on the established main function of the elastic modules of the metal’ temperature properties a new thermal compensation
algorithm, which does not involve liquid compensators, was introduced. Main advantages of the
new algorithm are demonstrated. Those advantages emerge due to using vacuum as a medium
surrounding the vibration transducer. One of the most notable benefits is significant extension
of the calibrated temperature range. A possibility of applying the algorithm for calibrating density
meters in extreme temperatures is introduced. Furthermore, formulas for calculatingthe
value of the oscillation period of the converter which account for temperature changes (thermal
compensation period) are presented. The advantages of using second order polynomial with
zero linear term as a calibration function are also provided. Methodology behind conducting
the experiments, types of equipment and measuring instruments are described in detail. Resul ting
experimental data for vibration transducers made of three different metals is presented. The
obtained data is analyzed, which led to a conclusion that application of suggested algorithm of
thermal compensation of liquid and gases density meters’ vibration transducers is feasible and
expedient.
