Resistive film on aluminum tube

Abstract

A tubular resistor assembly for use in electrical circuits for controlling automotive accessories, including a tubular aluminum or other metal substrate having watertight walls and open ends for connection to a fluid-carrying system, a resistor of a predetermined magnitude disposed on the tubular metal substrate. A control circuit, incorporating the resistor, controls the operation of one or more automotive accessory. The assembly may be used to intentionally heat a fluid passing through the tubular substrate, the fluid may be used to carry excess heat away from the resistor, or both. Multiple resistive elements may be included for multiple levels of control of such accessories as headlights, fan assemblies, and the like.

1 . A method of manufacturing a tubular resistor assembly, comprising:
 providing a section of tubular aluminum;   passivating the section of tubular aluminum by applying an anodization layer thereto; and   applying a microelectronic thick film material in a predetermined pattern to the anodized section of tubular aluminum.   
     
     
         2 . The method of  claim 1 , further comprising the step, after applying the thick film material, of firing the section of tubular aluminum to sinter the thick film material. 
     
     
         3 . The method of  claim 1 , wherein the step of applying the thick film material includes printing the thick film material onto the anodized section of tubular aluminum. 
     
     
         4 . The method of  claim 3 , wherein the step of printing the thick film material onto the anodized section of tubular aluminum includes screen printing the thick film material onto the anodized section of tubular aluminum. 
     
     
         5 . The method of  claim 4 , further comprising the step of applying a protective layer over the thick film material in order to protect the thick film material from environmental degradation. 
     
     
         6 . The method of  claim 5 , wherein the step of applying a protective layer includes applying a plastic overmold over the thick film material. 
     
     
         7 . The method of  claim 5 , wherein the step of applying a protective layer includes applying a glass over glaze over the thick film material.