Portable heater

Abstract

A portable heater includes a radiator having multiple tubular units and an electric heating element in the radiator for heating the diathermal fluid. A fan positioned above the sealed radiator directs air on the upper portions of the tubular units to enhance convection of the fluid.

I claim:  
     
         1 . A portable heater comprising: 
 (a) a sealed radiator containing a diathermal fluid, the radiator including a plurality of tubular radiator units, the tubular radiator units having respective upper portions and respective lower portions;    (b) at least one electric heating element positioned within the sealed radiator;    (c) a fan positioned above the sealed radiator for directing air on the upper portions of the tubular radiator units, the fan being effective to cool the upper portions of the tubular units to enhance thermal convection of the diathermal fluid within the tubular radiator units.    
     
     
         2 . A portable heater according to  claim 1  wherein the fan comprises a centrifugal fan.  
     
     
         3 . A portable heater according to  claim 2  further comprising an electric motor for driving the centrifugal fan.  
     
     
         4 . A portable heater according to  claim 3  wherein the electric motor operates at low rpm.  
     
     
         5 . A portable heater according to  claim 4  wherein the electric motor operates at less than 2500 rpm.  
     
     
         6 . A portable heater according to  claim 5  wherein the electric motor operates at less than 1000 rpm.  
     
     
         7 . A portable heater according to  claim 1  further comprising a cover enclosing the fan.