Electric heater for tumble dryers

Abstract

The electric heater for tumble dryer devices, object of the present invention, does not need the large size presently required to provide high powers. Furthermore, the particular shape of the resistive member reduces the vibrations transmitted to the apparatus and therefore the noise felt by the user. The particular shape of the heater determines a lower tendency to dust deposition on the heating member and a higher safety against short circuits in case of filament breakage.

1 . An electric heater for tumble dryer devices, comprising
 at least one resistive member,   a support structure for supporting said at least one resistive member,   wherein said support structure comprises flat parts, which are connected to one another so as to define a polygonal shape of the structure, having at least one open side,   and wherein said at least one resistive member comprises a flattened filament which is bent so as to define a plurality of zigzags, said filament being arranged on a plane which is substantially perpendicular to each flat part of the support structure.   
   
   
       2 . A heater according to  claim 1 , wherein each flat part is formed by three overlaying layers of an insulating material. 
   
   
       3 . A heater according to  claim 2 , wherein each flat part is provided, at one longitudinal edge thereof, with a substantially L-shaped support member, having a short arm connected to the flat part and a long arm adapted to be connected to a housing of the heater, so that flat parts are arranged along plans which are orthogonal to the bottom of said housing. 
   
   
       4 . A heater according to  claim 2 , wherein all flat parts are secured to a single support member adapted to be connected to a housing of the heater, so that the flat parts are arranged along plans which are orthogonal to the bottom of said housing. 
   
   
       5 . A heater according to  claim 1 , wherein said at least one resistive member is arranged outside or inside the support structure. 
   
   
       6 . A heater according to  claim 1 , wherein there are provided one first resistive member arranged outside the support structure and at least one second resistive member arranged inside said support structure. 
   
   
       7 . A heater according to  claim 2 , wherein said at least one resistive member is arranged outside or inside the support structure. 
   
   
       8 . A heater according to  claim 2 , wherein there are provided one first resistive member arranged outside the support structure and at least one second resistive member arranged inside said support structure. 
   
   
       9 . A heater according to  claim 8 , wherein there are provided two second resistive members ( 9 ) arranged inside the support structure. 
   
   
       10 . A heater according to  claim 7 , wherein an outer layer or an inner layer of each flat part are provided with a first longitudinal series of holes within which first tips of said at least one resistive member are secured. 
   
   
       11 . A heater according to  claim 8 , wherein an outer layer is provided with a first longitudinal series of holes within which first tips of said first resistive member are secured, and wherein an inner layer is provided with at least a second longitudinal series of holes within which first tips of said at least one second resistive member are secured. 
   
   
       12 . A heater according to  claim 2 , wherein there is provided at least a slit open at the ends of the inner layers of each flat part and/or at least a slit open at the ends of the outer layers of each flat part suitable for defining a passage for a turn of said at least one resistive member between two subsequent flat parts.