Flow heater and method for operating a flow heater

Abstract

Disclosed is a flow heater having an inlet, an outlet, and an electrical interface. The flow heater includes multiple heater modules that each have a module inlet connected to the inlet, a module outlet connected to the outlet, a heating element for heating liquid flowing from the module inlet to the module outlet, and an electrical module interface connected to the electrical interface.

What is claimed is: 
     
         1 . A flow heater, comprising:
 an inlet, an outlet, and an electrical interface; and   a plurality of heater modules that each comprise:
 a module inlet connected to the inlet; 
 a module outlet connected to the outlet; 
 a heating element for heating liquid flowing from the module inlet to the module outlet; and 
 an electrical module interface connected to the electrical interface. 
   
     
     
         2 . The flow heater according to  claim 1 , wherein the module inlets of the heater modules are connected in parallel to the inlet. 
     
     
         3 . The flow heater according to  claim 1 , wherein the heater modules are connected in series, wherein liquid to be heated flows through the heater modules one after another. 
     
     
         4 . The flow heater according to  claim 1 , wherein the heater modules are stacked on top of each other. 
     
     
         5 . The flow heater according to  claim 1 , further comprising a frame that carries the electrical interface, the inlet, the outlet, and connecting spigots that connect the inlet to the module inlets and the outlet to the module outlets, respectively. 
     
     
         6 . The flow heater according to  claim 5 , wherein the heater modules are held by the frame. 
     
     
         7 . The flow heater according to  claim 1 , further comprising an internal bus connecting the module electrical interfaces. 
     
     
         8 . The flow heater according to  claim 7 , wherein the internal bus is provided on the frame. 
     
     
         9 . The flow heater according to  claim 7 , further comprising a control unit connected to the electrical interface and to the internal bus. 
     
     
         10 . The flow heater according to  claim 9 , wherein the control unit is provided on the frame. 
     
     
         11 . The flow heater according to  claim 7 , wherein one of heater modules comprises a control unit that controls the other heater modules via the internal bus. 
     
     
         12 . The flow heater according to  claim 1 , wherein the electrical interface comprises a first plug connector for connecting to a source of heating current and a second plug connector for connecting to a vehicle control unit. 
     
     
         13 . The flow heater according to  claim 1 , wherein the heating element is an electrical resistor. 
     
     
         14 . A method for operating a flow heater according to  claim 1 , wherein the heating power of each heater module is set individually. 
     
     
         15 . A method according to  claim 14 , wherein the control unit of the flow heater communicates with a vehicle control unit and provides operating parameters of the flow heater to the vehicle control unit.