Heat exchanger and method for treating the surface of said heat exchanger

Abstract

The invention relates to a heat exchanger provided with a hydrophilic surface coating ( 12 ) comprising a gel produced by a sol-gel method.

1 . A heat exchanger having an in particular hydrophilic surface coating, characterized in that the surface coating includes a gel which is produced in particular in a sol-gel process.  
   
   
       2 . The heat exchanger as claimed in  claim 1 , characterized in that the sol, which functions as a coating substance in a sol-gel process, contains alkoxy compounds of elements from main group III and/or of elements from main group IV and/or of transition metals.  
   
   
       3 . The heat exchanger as claimed in  claim 2 , characterized in that the transition metals belong to transition group IV and/or V.  
   
   
       4 . The heat exchanger as claimed in  claim 2 , characterized in that in the alkoxy compounds some of the hydrolysable alkoxy radicals are substituted by alkyl and/or aryl radicals, or in that a mixture of pure alkoxy compounds and alkoxy compounds which partly contain alkyl and/or aryl radicals is provided.  
   
   
       5 . The heat exchanger as claimed in  claim 1 , characterized in that the surface coating contains nanoparticles, coated nanoparticles and/or grafted nanoparticles comprising or consisting of oxides.  
   
   
       6 . The heat exchanger as claimed in  claim 5 , characterized in that oxides of the elements from main group II and/or main group III and/or oxides of germanium, tin, lead and/or oxides of the transition metals and/or oxides of zinc and/or oxides of cerium are provided.  
   
   
       7 . The heat exchanger as claimed in  claim 6 , characterized in that the transition metals belong to transition IV and/or V.  
   
   
       8 . The heat exchanger as claimed in  claim 1 , characterized in that the surface coating contains nanoparticles, coated nanoparticles and/or grafted nanoparticles comprising or consisting of hydrated oxides and/or nitrides and/or carbides.  
   
   
       9 . The heat exchanger as claimed in  claim 8 , characterized in that the hydrated oxides, nitrides and carbides comprise elements from main group III and/or main group IV and/or transition metals and/or cerium.  
   
   
       10 . The heat exchanger as claimed in  claim 9 , characterized in that a transition metal belongs to transition group IV and/or V or is zinc.  
   
   
       11 . The heat exchanger as claimed in  claim 1 , characterized in that the nanoparticles, coated nanoparticles and/or grafted nanoparticles have a mean diameter of from 1 to 1000 nm.  
   
   
       12 . The heat exchanger as claimed in  claim 1 , characterized in that the surface coating includes constituents with an antimicrobial action.  
   
   
       13 . A process for coating a heat exchanger with an in particular hydrophilic surface coating the surface coating being produced by means of a sol-gel process.  
   
   
       14 . The process for coating a heat exchanger as claimed in  claim 13 , characterized in that the surface coating is applied by means of dipping, flooding and/or spraying.  
   
   
       15 . The process for coating a heat exchanger as claimed in  claim 13 , characterized in that a pre-treatment by means of an acidic or alkaline pickle is carried out, with subsequent scale removal and/or a conversion treatment.  
   
   
       16 . The process for coating a heat exchanger as claimed in  claim 15 , characterized in that mixed oxides and/or mixed fluorides are formed during the conversion treatment.  
   
   
       17 . The process for coating a heat exchanger as claimed in  claim 13 , characterized in that a drying process is carried out after a pre-treatment by means of an acidic or alkaline pickle with subsequent scale removal and/or a conversion treatment.  
   
   
       18 . The process for coating a heat exchanger as claimed in  claim 13 , characterized in that the operation of applying the surface coating is followed by a drying operation.  
   
   
       19 . The process for coating a heat exchanger as claimed in  claim 13 , characterized in that a surface coating which contains nanoparticles, coated nanoparticles and/or grafted nanoparticles is applied.