Two-pass evaporator

Abstract

A two-pass evaporator suitable for use in an automobile includes various pressure drop devices to aliquot refrigerant into tubes that make up the two-pass evaporator. The two-pass evaporator includes a first pressure-drop device configured to receive and expand a liquid phase refrigerant into a first mixture of two-phase refrigerant; and a second pressure-drop device configured to receive and expand the first mixture of two-phase refrigerant into a second mixture of two-phase refrigerant and aliquot the second mixture of two-phase refrigerant to the first end of the first plurality of tubes. The two-pass evaporator includes a transition manifold that may house a flow-modulation plate disposed therein and configured to segregate the transition manifold into an upstream portion and a downstream portion. The flow-modulation device works in conjunction with the upstream pressure drop devices to aliquot refrigerant from the first plurality of tubes to the second plurality of tubes.

We claim: 
     
         1 . A two-pass evaporator suitable for use in an automobile, said two-pass evaporator comprising:
 an inlet manifold configured to define a chamber for containing refrigerant, define an inlet port for receiving refrigerant into the chamber, and hydraulically couple the inlet port to a first end of a first plurality of tubes;   a transition manifold configured to hydraulically couple a second end of the first plurality of tubes to a first end of a second plurality of tubes;   an outlet manifold located proximate to the inlet manifold, said outlet manifold configured to define an outlet port and hydraulically couple a second end of the second plurality of tubes to the outlet port;   a first pressure-drop device located proximate to the inlet port, said first pressure-drop device configured to receive and expand a liquid phase refrigerant into a first mixture of two-phase refrigerant;   a second pressure-drop device located within the inlet manifold, said second pressure-drop device configured to receive and expand said first mixture of two-phase refrigerant into a second mixture of two-phase refrigerant and aliquot said second mixture of two-phase refrigerant to the first end of the first plurality of tubes, wherein the first pressure-drop device and the second pressure-drop device cooperate to form a hybrid expansion device.   
     
     
         2 . The two-pass evaporator in accordance with  claim 1 , wherein the transition manifold includes a flow-modulation plate disposed therein and configured to segregate the transition manifold into an upstream portion and a downstream portion, and aliquot refrigerant from the first plurality of tubes to the second plurality of tubes. 
     
     
         3 . The two-pass evaporator in accordance with  claim 2 , wherein the flow-modulation plate defines a plurality of openings configured to aliquot refrigerant from the first plurality of tubes to the second plurality of tubes.