摘要 |
The present invention provides a heater having a heat resistant, thermally and electrically insulating tube having an elongated opening through a wall of the tube and extending along at least a portion of the tube, and a heating element positioned within the tube and extending along at least a portion of the opening. A first portion of a section of the element extending along the opening is exposed and a second portion of the section of the element extending along the opening is shielded by the tube. In one particular embodiment of the invention, the tube is a cylindrically shaped aluminum oxide tube, the heating element is a nichrome wire coil, and the elongated opening is a slot having a constant width which extends between opposing ends of the tube. |