Abstract: An economizer is disclosed having a plurality of stages for flash cooling refrigerant liquid for use in a refrigeration system. The refrigerant liquid is cooled by evaporation of a portion of the liquid as it passes through throttling means into chambers of successively lower pressure. Sump means are provided to collect the refrigerant liquid flowing between the chambers. As the refrigerant enters each chamber, it is deflected by distribution means, thereby effecting more efficient separation of the flashed refrigerant vapor from the resulting liquid spray.