MASS FLOW CONTROL OF A WORKING FLUID

摘要

Apparatus for detecting working fluid state in a heat transfer system (10) of the type having an evaporator (14) and an expansion valve (22) for controlling mass flow of the working fluid (12) to the evaporator (14), comprises a first sensor (150) disposed in the working fluid (12) on the outlet side of the evaporator (14); the first sensor (150) producing a first signal related to the working fluid (12) state; a second sensor (250) disposed in the working fluid (12) on the inlet side of the evaporator (14); the second sensor (250) producing a second signal related to a pressure dependent characteristic of the working fluid (12); and a control circuit (40) for receiving the first and second signals and determining the working fluid (12) state based on a ratio of the first and second signals.