Plate heat exchanger

Abstract

The invention relates to a plate heat exchanger and a method of manufacturing a plate heat exchanger. The plate heat exchanger includes a number of heat exchanger plates ( 1, 1′, 1 ″) which are provided beside each other and connected to each other by means of a braze connection. The heat exchanger plates are substantially manufactured in stainless steel containing chromium. The plate heat exchanger includes a number of port channels extending through at least some of the heat exchanger plates. Each port channel is surrounding by a connection surface ( 5 ) for connection of the port channel to a pipe member ( 6 ). The connection surface includes a material permitting brazing of the pipe member to the connection surface in a more easy manner than stainless steel.

1 - 30 . (canceled)  
   
   
       31 . A plate heat exchanger comprising a number of heat exchanger plates, which are arranged beside each other and connected to each other by means of a braze connection, 
 wherein the heat exchanger plates are substantially manufactured in stainless steel containing chromium,    wherein the plate heat exchanger includes a number of port channels extending through at least some of the heat exchanger plates,    wherein one or more of the port channels are surrounded by a connection surface for connection of the one or more port channels to a pipe member, and    wherein the connection surface includes a material that permits brazing of said pipe member to the connection surface in a more easy manner than to stainless steel, wherein said material is more reduction susceptible than chromium dioxide.    
   
   
       32 . A plate heat exchanger according to  claim 31 , wherein said material includes nickel.  
   
   
       33 . A plate heat exchanger according to  claim 31 , wherein said material includes copper.  
   
   
       34 . A plate heat exchanger according to  claim 31 , wherein said braze connection of the heat exchanger plates is accomplished by a braze process.  
   
   
       35 . A plate heat exchanger according to  claim 31 , wherein said material is bound to the stainless steel through diffusion.  
   
   
       36 . A plate heat exchanger according to  claim 35 , wherein said diffusion is accomplished during a braze process.  
   
   
       37 . A plate heat exchanger according to  claim 31 , wherein one of said heat exchanger plates forms an outer heat exchanger plate which has a respective outer surface area surrounding a respective port channel.  
   
   
       38 . A plate heat exchanger according to  claim 37 , wherein said material is supplied to the outer surface area for forming said connection surface.  
   
   
       39 . A plate heat exchanger according to  claim 31 , wherein the plate heat exchanger includes a connection member at each port channel, wherein a connection member forms said connection surface.  
   
   
       40 . A plate heat exchanger according to  claim 37 , wherein a connection member is attached to the outer surface area.  
   
   
       41 . A plate heat exchanger according to  claim 40 , wherein the connection member has a primary surface onto which said material is applied for forming said connection surface.  
   
   
       42 . A plate heat exchanger according to  claim 41 , wherein the primary surface has a rough surface finish, which is accomplished through abrasive blasting or any similar roughening process and which facilitates wetting of the primary surface with said material.  
   
   
       43 . A plate heat exchanger according to  claim 42 , wherein said material has been applied onto the primary surface by means of and during a braze process.  
   
   
       44 . A plate heat exchanger according to  claim 39 , wherein the connection member is substantially manufactured in a stainless steel containing chromium.  
   
   
       45 . A plate heat exchanger according to  claim 39 , wherein the connection member is substantially manufactured in an alloy substantially containing copper and nickel.  
   
   
       46 . A plate heat exchanger according to  claim 45 , wherein said alloy contains 55 to 95 percent by weight copper and 5 to 45 percent by weight nickel.  
   
   
       47 . A plate heat exchanger according to  claim 39 , wherein the connection member is designed as a pipe nipple.  
   
   
       48 . A plate heat exchanger according to  claim 39 , wherein the connection member is designed as a washer.  
   
   
       49 . A method for manufacturing a plate heat exchanger including a number of heat exchanger plates, which are substantially manufactured in stainless steel containing chromium, and including a number of port channels extending through at least some of the heat exchanger plates, and wherein one or more of the port channels are surrounded by a connection surface for connection of the port channel to a pipe member, the method comprising: 
 applying a material, which forms the connection surface and which permits brazing of said pipe member to the connection surface in a more easy manner than to stainless steel, wherein said material is more reduction susceptible than chromium dioxide,    arranging the heat exchanger plates beside each other, and    joining the heat exchanger plates to each other by means of a braze connection.    
   
   
       50 . A method according to  claim 49 , wherein said material includes nickel.  
   
   
       51 . A method according to  claim 49 , wherein said material includes copper.  
   
   
       52 . A method according to  claim 49 , wherein said joining includes a braze process with brazing of the heat exchanger plates at vacuum-like pressure conditions or in an atmosphere with substantially inert gas or a reducing gas.  
   
   
       53 . A method according to  claim 52 , wherein the brazing is performed in such a manner that said material is bound to the stainless steel through diffusion.  
   
   
       54 . A method according to  claim 49 , wherein one of said heat exchanger plates forms an outer heat exchanger plate having a respective outer surface area surrounding a respective port channel and wherein said applying includes that said material is applied to the outer surface area for forming said connection surface.  
   
   
       55 . A method according to  claim 49 , wherein one of said heat exchanger plates forms an outer heat exchanger plate having a respective outer surface area surrounding a respective port channel and wherein the method further includes: 
 applying a connection member to the outer surface area at each port channel before said joining of the heat exchanger plates, wherein the connection member forms said connection surface.    
   
   
       56 . A method according to  claim 55 , wherein the connection member has a primary surface and wherein said applying a material includes applying said material to the primary surface for forming said connection surface by means of and during said braze process.  
   
   
       57 . A method according to  claim 56 , further including an initial roughening of the primary surface through blasting or the like for accomplishing rough surface finish facilitating wetting of the primary surface by said material during said braze process.  
   
   
       58 . A method according to  claim 55 , wherein the connection member is substantially manufactured in stainless steel containing chromium.  
   
   
       59 . A method according to  claim 58 , wherein the connection member is substantially manufactured in an alloy substantially containing copper and nickel.  
   
   
       60 . A method according to  claim 59 , wherein said alloy includes 55 to 95 percent by weight copper and 5 to 45 percent by weight nickel.