Insulating surface coating on heat exchangers for reducing thermal stresses

Abstract

The invention relates to a plate heat exchanger (10) having a plate heat exchanger block (11), which has a plurality of partitions (4, 5) arranged parallel to one another in the form of separating plates which form a plurality of heat exchange passages (1a, 1b) for fluids which are to be brought into indirect heat exchange relationship with one another. The heat exchange passages are closed off from the outside by lateral strips (8), and each heat exchange passage (1a, 1b) has an inlet (9) for inflow of a fluid and an outlet (19) for outflow of the fluid. According to the invention, one or more partitions (4, 5) and/or one or more heat-conducting elements (2, 3) in each case have a coating (41) made of a heat-insulating material. The invention further relates to a method for producing a polymer laminate and to a method for joining prefabricated polymer components to each other.

1 . Plate heat exchanger ( 10 ) having a plate heat exchanger block ( 11 ) which has a plurality of partitions ( 4 ,  5 ) which are arranged parallel to one another and form a plurality of heat exchange passages ( 1   a ,  1   b ) for fluids which are to be brought into indirect heat exchange with one another, wherein the heat exchange passages ( 1   a ,  1   b ) are delimited by lateral strips ( 8 ), and wherein a heat-conducting element ( 2 ,  3 ) is arranged between adjacent partitions ( 4 ,  5 ), and wherein the heat exchange passages ( 1   a ,  1   b ) each have an inlet ( 9 ) for inflow of a fluid and an outlet ( 19 ) for outflow of the fluid,
 characterized in that   a plurality of partitions ( 4 ,  5 ) and/or a plurality of heat-conducting elements ( 2 ,  3 ) each have a coating ( 41 ) of a heat-insulating material.   
     
     
         2 . Plate heat exchanger according to  claim 1 , characterized in that the partition ( 4 ,  5 ) having the coating ( 41 ) and/or that the heat-conducting element ( 2 ,  3 ) having the coating ( 41 ) has a first section (A 1 ) arranged on the inlet ( 9 ) and a second section (A 2 ) connected to the first section (A 1 ), wherein the second section (A 2 ) is further away from the inlet ( 9 ) than the first section (A 1 ), and wherein the first section (A 1 ) has the coating ( 41 ), and wherein the second section (A 2 ) has no heat-insulating coating. 
     
     
         3 . Plate heat exchanger according to  claim 1 , characterized in that the plate heat exchanger block ( 11 ) has at least first heat exchange passages ( 1   a ) for receiving a first fluid (B) and second heat exchange passages ( 1   b ) for receiving a second fluid (A), wherein the first heat exchange passages ( 1   a ) each have a coating ( 41 ) of the heat-insulating material, and wherein the second heat exchange passages ( 1   b ) have no coating of the heat-insulating material. 
     
     
         4 . Plate heat exchanger according to  claim 1 , characterized in that the heat-insulating material is one of the following materials or has one of the following materials: a plastic, a polymer, a ceramic. 
     
     
         5 . Plate heat exchanger according to  claim 1 , characterized in that the heat-insulating material has a thermal conductivity coefficient of less than 5 W/mK—in particular, less than 1 W/mK. 
     
     
         6 . Plate heat exchanger according to  claim 1 , characterized in that the respective coating ( 41 ) has a thickness (D 1 ) of less than or equal to 0.2 mm. 
     
     
         7 . Plate heat exchanger according to  claim 1 , characterized in that, for introducing fluids (B) via the inlets ( 9 ) of the first heat exchange passages ( 1   a ) and via the inlets ( 9 ) of the second heat exchange passages ( 1   b ), a collector ( 7 ) having a nozzle ( 6 ) is attached in each case. 
     
     
         8 . Plate heat exchanger according to  claim 7 , characterized in that the collector ( 7 ) and/or the nozzle ( 6 ) of the first heat exchange passages ( 1   a ) has a coating ( 41 ) of the heat-insulating material. 
     
     
         9 . Plate heat exchanger according to  claim 1 , characterized in that the respective heat-conducting element ( 2 ,  3 ) has a corrugated structure with alternating foot sections ( 12 ) and head sections ( 14 ), wherein the respective foot section ( 12 ) is connected via a web ( 13 ) to an adjacent head section ( 14 ). 
     
     
         10 . Method for the production of a plate heat exchanger according to  claim 1 , wherein a flowable material, which, in the hardened state, forms a heat-insulating material, is introduced into heat exchange passages ( 1   a ) of the plate heat exchanger block ( 11 ), the partitions and/or heat-conducting elements ( 2 ,  3 ) and/or lateral strips ( 8 ) of which are to receive the coating ( 41 ), wherein the material is cured so as to form the coatings ( 41 ). 
     
     
         11 . Method according to  claim 10 , characterized in that the plate heat exchanger block ( 11 ) is immersed, at least in sections, in the flowable material in order to introduce the flowable material into the corresponding heat exchange passages ( 1 ). 
     
     
         12 . Method for operating a plate heat exchanger according to  claim 1 , wherein at least one first fluid (B) and one second fluid (A) are introduced into at least one heat exchange passage ( 1   a ,  1   b ) of the plate heat exchanger so that the fluids (B, A) can exchange heat. 
     
     
         13 . Method according to  claim 12 , wherein the first fluid (B) is introduced into the at least one first heat exchange passage ( 1   a ), and the second fluid (A) is introduced into the at least one second heat exchange passage ( 1   b ). 
     
     
         14 . Method according to  claim 12 , wherein, when the plate heat exchanger is started up, the first fluid (B) is introduced into the at least one first heat exchange passage ( 1   a ) before the second fluid (A) is introduced into the at least one second heat exchange passage ( 1   b ). 
     
     
         15 . Method according to  claim 12 , wherein the first fluid (B) is introduced into the at least one first heat exchange passage ( 1   a ) via the nozzle ( 7 ) and collector ( 6 ) which is arranged above the inlet ( 9 ) of the at least one first heat exchange passage ( 1   a ). 
     
     
         16 . Method according to  claim 12 , wherein the at least one first fluid (B), which is introduced into the plate heat exchanger prior to all other fluids when the plate heat exchanger is started up, has a temperature which differs by a temperature differential from a temperature of the plate heat exchanger prior to startup.