Heat exchanger with improved corrosion resistance

Abstract

The present invention relates to a plate package for a plate heat exchanger and a plate heat exchanger made of materials with improved anti-corrosion properties for highly corrosive fluids such as hydrochloric acid.

1 . A permanently joined plate package for a plate heat exchanger made of stainless steel, copper or carbon steel wherein at least all surfaces in contact with media of at least one of the flow sides of the plate package have an alloy bonded coating of a tantalum containing compound. 
     
     
         2 . A permanently joined plate package according to  claim 1 , wherein the tantalum containing compound is metal tantalum, tantalum oxide and/or tantalum nitride, preferably metal tantalum and/or tantalum oxide, more preferably metal tantalum. 
     
     
         3 . A permanently joined plate package according to  claim 1 , wherein the plate package was assembled using welding, fusion bonding or brazing, preferably fusion bonding or copper brazing. 
     
     
         4 . A permanently joined plate according to  claim 1 , wherein the plate package is made of stainless steel and was assembled using welding, fusion bonding or brazing, preferably fusion bonding or copper brazing. 
     
     
         5 . A permanently joined plate package according to  claim 1 , wherein the coating of tantalum containing compound has a thickness of about 1-300 μm. 
     
     
         6 . A plate heat exchanger wherein it comprises a plate package of the kind as defined in  claim 1 . 
     
     
         7 . A plate heat exchanger according to  claim 6 , wherein said heat exchanger has frames and/or mounting plates that are a part of at least one of the flow sides of the heat exchanger and said frames and/or mounting plates are made of tantalum, or stainless steel or carbon steel having an alloy bonded coating of a tantalum containing compound, preferably stainless steel or carbon steel having an alloy bonded coating of a tantalum containing compound, more preferably stainless steel having an alloy bonded coating of a tantalum containing compound. 
     
     
         8 . A plate heat exchanger according to  claim 7 , wherein the plate heat exchanger is permanently joined and is made of stainless steel or carbon steel and all surfaces of at least one of the flow sides of the plate heat exchanger have an alloy bonded coating of a tantalum containing compound. 
     
     
         9 . A permanently joined plate package according to  claim 1 , wherein the coating of tantalum containing compound has a thickness of about 1-125 μm. 
     
     
         10 . A permanently joined plate package according to  claim 1 , wherein the coating of tantalum containing compound has a thickness of about 10-40 μm. 
     
     
         11 . A permanently joined plate package according to  claim 1 , wherein the coating of tantalum containing compound has a thickness of about 15-25 μm.