Measuring device for detecting a liquid component in refrigerant

Claim 1

Measuring appratus for a refrigeration system of the type having in series a compressor, a condenser, an expansion valve, an evaporator and a suction conduit between said evaporator and said compressor having an associated heating element for heating said suction conduit, said apparatus including means for detecting the relative quantity of a liquid component in refrigerant in said suction conduit leaving said evaporator, said means including a first temperature measuring sensor in thermal contact with said suction conduit providing a first sensor output signal, said first temperature measuring sensor being located just sufficiently away from said heating element so as to be substantially unaffected by said heating element, and a second temperature measuring sensor in thermal contact with said suction conduit to provide a reference temperature output signal, said second temperature measuring sensor being located at a point where the temperature of said suction conduit is substantially unaffected by the relative quantity of said liquid component in said refrigerant, whereby the difference between the first sensor output signal and the reference temperature output signal is indicative of the relative quantity of said liquid component in said refrigerant.