Evaporator

Abstract

The present invention is a cross-flow evaporator adapted to generate vapor from the heat of the exhaust gases from an internal combustion engine. The evaporator is constituted, among other elements, by two plates spaced from one another which contain chambers. The heat exchange tubes alternately communicate the chambers of both plates, establishing a specific path for the fluid intended to change phase. The tubes extending between the chambers of the two plates are arranged transverse to the flow of the hot gas. This evaporator is suitable for heat recovery systems using a Rankine cycle, making use of the heat from the exhaust gases. The invention is characterized by a special configuration of the walls which prevents the crack failure or damage caused as a result of the differential expansion between the exchange tubes and said walls.

1 . An evaporator for the evaporation of a first fluid by means of the heat provided by a second fluid, the second fluid being a hot gas, wherein said evaporator comprises:
 a first plate ( 1 ) and a second plate ( 2 ) facing one another and arranged spaced from one another, defining an inner face, the face facing the other plate, and an outer face opposite the inner face; wherein each of the plates ( 1 ,  2 ) comprises a plurality of chambers ( 1 . 1 ,  2 . 1 );   an intake manifold ( 4 ) of the first fluid and an exhaust manifold ( 5 ) of the first fluid situated in fluid communication with one another and with at least one different chamber ( 1 . 1 ,  2 . 1 ) of any of the plates ( 1 ,  2 );   a plurality of heat exchange tubes ( 3 ) wherein each of the heat exchange tubes ( 3 ) extends between a chamber ( 1 . 1 ) of the first plate ( 1 ) and a chamber ( 2 . 1 ) of the second plate ( 2 ); wherein each chamber ( 1 . 1 ,  2 . 1 ) of one plate ( 1 ,  2 ) is in fluid communication with two or more chambers ( 1 . 1 ,  2 . 1 ) of the other plate ( 1 ,  2 ) by means of at least two heat exchange tubes ( 3 ), except the chambers ( 1 . 1 ,  2 . 1 ) in fluid communication with the intake manifold ( 4 ) or the exhaust manifold ( 5 );   there being for each of the heat exchange tubes ( 3 ) a path of fluid communication from the intake manifold ( 4 ) to the exhaust manifold ( 5 ) passing through the inside of said heat exchange tube ( 3 );   two first side walls ( 6 ) extending between the first plate ( 1 ) and the second plate ( 2 ) housing the plurality of heat exchange tubes ( 3 ) and establishing between both a space for the passage of the second fluid, wherein the second fluid enters through an inlet (I 2 ) and exits through an outlet (O 2 );   characterized in that   the first side walls ( 6 ) are elastically deformable, which allows compensating the differential expansion between the heat exchange tubes ( 3 ) and said first side walls ( 6 ).   
     
     
         2 . The evaporator according to  claim 1 , wherein the tubes ( 3 ) are elastically deformable according to their longitudinal direction. 
     
     
         3 . The evaporator according to  claim 1 , wherein said evaporator additionally comprises second side walls ( 7 ), situated between the first plate ( 1 ) and the second plate ( 2 ), these second side walls ( 7 ) being spaced from the first side walls ( 6 ), wherein the second side walls ( 7 ) are elastically deformable and are arranged internally with respect to the first side walls ( 6 ). 
     
     
         4 . The evaporator according to  claim 3 , wherein the first side walls ( 6 ), the second side walls ( 7 ), or both, are elastically deformable by means of one or more crimps or corrugations ( 6 . 1 ,  7 . 1 ). 
     
     
         5 . The evaporator according to  claim 4 , wherein the crimps ( 6 . 1 ,  7 . 1 ) have a main direction according to the longitudinal direction established between the inlet (I 2 ) and the outlet (O 2 ) of the second fluid. 
     
     
         6 . The evaporator according to  claim 4 , wherein the crimps ( 6 . 1 ,  7 . 1 ) have a sinusoidal path. 
     
     
         7 . The evaporator according to  claim 3 , wherein the stiffness constant of the elastically deformable second side walls ( 7 ) is less than the stiffness constant of the elastically deformable first side walls ( 6 ). 
     
     
         8 . The evaporator according to  claim 1 , wherein the inlet (I 2 ), the outlet (O 2 ), or both, have a manifold ( 8 ,  9 ). 
     
     
         9 . The evaporator according to  claim 3 , wherein:
 a. the second side walls ( 7 ) are prolonged inside one or more intake/exhaust manifolds of the second fluid ( 8 ,  9 ); and,   b. at least one prolongation of the second side walls ( 7 ) inside the manifold ( 8 ,  9 ) is spaced from said manifold ( 8 ,  9 ).   
     
     
         10 . The evaporator according to  claim 3 , wherein between the first side walls ( 6 ) and the second side walls ( 7 ) there is a chamber that is in fluid communication with the intake manifold ( 4 ) of the first fluid such that the entrance of the first fluid in the evaporator is carried out by means of previous passage through the chamber formed between the first and second side walls ( 6 ,  7 ). 
     
     
         11 . The evaporator according to  claim 1 , comprising:
 either a first shield plate ( 11 ) located in the passage space of the second fluid, spaced from the first plate ( 1 ), or   a second shield plate ( 11 ) located in the passage space of the second fluid, spaced from the second plate ( 2 ); or, or   both the first and second shield plates ( 11 );   
       wherein the shield plates ( 11 ) have multiple of perforations for the passage of the heat exchange tubes ( 3 ) leaving a chamber between said shield plates ( 11 ) and their corresponding plates ( 1 ,  2 ) for protecting the welds between the exchange tubes ( 3 ) and said plates ( 1 ,  2 ). 
     
     
         12 . The evaporator according to  claim 3 , wherein the second side walls ( 7 ) and the shield plate or plates ( 11 ) are configured as a single part. 
     
     
         13 . The evaporator according to  claim 3 , wherein there are thermal insulation means in the chamber ( 10 ) situated between the first side walls ( 6 ) and the second side walls ( 7 ). 
     
     
         14 . The evaporator according to  claim 3 , wherein either the first side walls ( 6 ), the second side walls ( 7 ), or both ( 6 ,  7 ), extend along the outer side of the first plate ( 1 ) and along the outer side of the second plate ( 2 ), being attached to one another, configuring a shell. 
     
     
         15 . The evaporator according to  claim 14 , wherein either the first side walls ( 6 ), the second side walls ( 7 ) or both, are configured in the form of two U-shaped halves attached to one another. 
     
     
         16 . The evaporator according to  claim 1 , wherein the first plate ( 1 ), the second plate ( 2 ), or both ( 1 ,  2 ), allow bending according to the direction perpendicular to the longitudinal direction established between the inlet (I 2 ) and the outlet (O 2 ) of the second fluid. 
     
     
         17 . A heat recovery system for internal combustion vehicles comprising an evaporator according to  claim 1 .