Scraped surface heat exchanger for continuous heating or cooling of viscous masses

Abstract

A heat exchanger, preferably a scraped surface heat exchanger, is designed to heat or cool viscous or highly viscous material. The heat exchanger is equipped with a product cylinder ( 3 ) surrounded by a heat transfer medium and containing a rotationally driven shaft ( 2 ). The shaft and the product cylinder form a gap ( 10 ) with an annular cross-section for receiving the material to be treated. To avoid the use of coolant substances that are harmful to the environment or the operator, Peltier elements ( 5 ) are arranged between the heat transfer medium and the product cylinder ( 3 ) on the side of the cylinder facing away from the annular gap ( 10 ). The Peltier elements cool the material to be treated on the secondary side, enabling water to be used as the coolant, the water posing no threat to the environment and being re-cooled without difficulty in water towers. The cooling process takes advantage of the effect of the thermal pump of the Peltier element.

1 . A scraped surface heat exchanger for continuous heating or cooling of viscous masses, the heat exchanger comprising a product cylinder ( 3 ) surrounded by a heat transfer medium and a rotationally driven shaft ( 2 ) arranged in the product cylinder ( 3 ) with a gap space ( 10 ) of annular cross section between the shaft ( 2 ) and the product cylinder ( 3 ) for receiving a mass to be treated, wherein Peltier elements ( 5 ) are arranged between the heat transfer medium and the product cylinder ( 3 ) on a side of the product cylinder facing away from the annular gap space ( 10 ).  
   
   
       2 . The heat exchanger according to  claim 1 , wherein the Peltier elements ( 5 ) are applied as heat pumps for cooling or, by reversal of a voltage supply to the Peltier elements, for heating the mass to be treated.  
   
   
       3 . The heat exchanger according to  claim 1 , wherein the Peltier elements ( 5 ) are arranged in an annular gap ( 7 ) through which the heat transfer medium flows and which is formed by the product cylinder ( 3 ) and an outer cylinder ( 8 ) surrounding the product cylinder.  
   
   
       4 . The heat exchanger according to  claim 1 , wherein the Peltier elements ( 5 ) are covered by a casing ( 6 ) of heat-conductive material.  
   
   
       5 . The heat exchanger according to  claim 1 , wherein the entire product cylinder ( 3 ) is designed as a Peltier element.  
   
   
       6 . The heat exchanger according to  claim 1 , wherein the entire product cylinder ( 3 ) on a side facing the Peltier elements ( 5 ) is designed with a plurality of axial, planar surfaces for accommodating planar Peltier elements.  
   
   
       7 . The heat exchanger according to  claim 1 , comprising a scraped surface heat exchanger.  
   
   
       8 . The heat exchanger according to  claim 7 , wherein scraper knives ( 1 ) are fastened on the rotationally driven shaft ( 2 ) in the annular gap space ( 10 ) for receiving the mass to be treated, and wherein the scraper knives ( 1 ) contact and scrape the surface of the cylinder ( 3 ).