Plasmatized heat exchanger

Abstract

The invention relates to a temperature-controlled, rotating, rotational symmetric heat exchanger, particularly for the pressing mechanism, drying mechanism or smoothing mechanism of a machine for producing web-like products such as paper webs or plastic films. The heat exchanger can be temperature-controlled preferably with fluids or vaporous heat transfer media or with heating involving electrical means. The aim of the invention is to improve a heat exchanger of the aforementioned type as to achieve surface hardnesses of far greater than 400-450 HV and to minimize the chemical/mechanical corrosion even at heat transfer capacities >80 kW/m. To this end, the heat exchanger is plamatized.

1 . Temperable, rotatable, rotationally symmetric heat exchanger of hardened and tempered forged steel, especially for the pressing, drying, or smoothing unit of a machine for the production of web-like products such as paper webs or plastic films, which heat exchanger can be tempered preferably with fluid or gaseous heat-transfer media or by an electrical heating system, wherein the heat exchanger is plasma-treated.  
   
   
       2 . Heat exchanger according to  claim 1 , wherein the surfaces of the necks of the rolls are partially or completely plasma-treated.  
   
   
       3 . Heat exchanger according to  claim 1 , wherein the contact surface of the heat exchanger with the web-like product is plasma-treated.  
   
   
       4 . Heat exchanger according to  claim 1 , wherein the surface of the barrel of the heat exchanger is plasma-treated.  
   
   
       5 . Heat exchanger according to  claim 1 , wherein the surface of the roll is plasma-treated.  
   
   
       6 . Heat exchanger according to  claim 1 , wherein the surfaces in contact with the heat-transfer medium are completely or partially plasma-treated.  
   
   
       7 . Heat exchanger according to  claim 1 , wherein a bonding layer is formed at the surface.  
   
   
       8 . Heat exchanger according to  claim 1 , wherein no bonding layer is formed at the surface.  
   
   
       9 . Heat exchanger according to  claim 1 , wherein subsurface corrosion is prevented.  
   
   
       10 . Heat exchanger according to  claim 1 , wherein the plasma-treated calender roll can be used at process temperatures between −20° C. and 500° C.