Method and apparatus for measuring a change in state of a subject fluid

Abstract

In a subject fluid, there is placed an apparatus for measuring a change in state of the fluid, said apparatus having a tubular body which, in turn, contains therein at least one heating sensor employing so-called hot wire method. A quantity of the fluid is introduced into the tubular body and a temperature of the heating sensor is measured by the heating sensor itself as the quantity of the fluid having been introduced into the tubular body is maintained in a state of laminar flow or a static state. The laminar flow is generated by fluid impeller means such as impeller vane, screw-type vane or propeller vane assembly or uniaxial eccentric pump. The static state is maintained y providing gateway means for passage of the fluid into or out from the tubular body and closing such gateway means. A temperature of the fluid having been introduced into the tubular body and maintained in said laminar or static state is measured and discharged out from the tubular body upon completion of said temperature measurements. A change in state of the fluid is determined based on the temperatures of the fluid and the heating sensor.