Evaporator Core: Description and Operation

The evaporator core is the plate/fin type with a multi-pass refrigerant flow path. A mixture of refrigerant and oil enters the bottom of the core through the evaporator inlet tube and is routed so that it flows upward through the first three partitioned plate/fin sections. The next four plate/fin sections are partitioned to force the refrigerant to flow downward toward the bottom of the evaporator core. The refrigerant then continues over to the remaining five plate/fin sections and then moves upward and out of the evaporator through the evaporator outlet tube. This S-pass flow pattern eliminates the need for the liquid refrigerant-and-oil bleed line that was used on earlier model plate/fin evaporator cores because of increased refrigerant flow velocity.