a liquid metering means disposed within the liquid metering means comprises a sealed hollow float chamber 14 a hinged metering plate or member 16 a stationary hinge pin 18 and a liquid metering orifice 20 affixed to the reservoir 12 is a first liquid inlet tube or port 22 in open fluid communication with the lower or outlet portion of the first heat exchange 6 through strainer dryer 24 fig1 the liquid metering orifice 20 through a second outlet tube or port 26 is in open fluid communication with the second heat exchange 10 through a liquid conduit 28 also affixed to the reservoir 12 is a vapor inlet tube or port 30 which is in open fluid communication with an intermediate point 32 on the first heat exchange 6 through vapor conduit 34 fig1 in addition an adjustable metering stop 36 is affixed to the reservoir 12 a vertically disposed liquid vapor baffle plate 38 separates the reservoir 12 into a liquid receiving chamber 40 and a vapor receiving chamber 42 vapor vent aperture 44 and liquid metering member aperture 46 are formed in the upper and lower portion of the vertically disposed liquid vapor baffle plate 38 respectively as best shown in fig3 the vapor flow control device 4 comprises an enclosed vertical liquid vapor reservoir 48 having liquid trapping means liquid evaporating means and oil ejecting means disposed therein the lower portion of the enclosed reservoir 48 is in open fluid communication with the outlet end of the second heat exchange 10 through a vapor liquid inlet tube or port 50 and vapor conduit 52 fig1 the liquid trapping liquid evaporating.