US PATENT SUBCLASS 373 / 123
.~.~.~ With preheating

Current as of: June, 1999
Click HD for Main Headings
Click for All Classes

Internet Version by PATENTEC © 1999      Terms of Use


373 /   HD   INDUSTRIAL ELECTRIC HEATING FURNACES

109  DF  RESISTANCE FURNACE DEVICE {7}
117  DF  .~ With heating element detail {7}
120  DF  .~.~ Open circuit (e.g., charge internal resistance heating) {4}
123.~.~.~ With preheating {1}
124  DF  .~.~.~.~> Including starting resistor

DEFINITION

Classification: 373/123

With preheating:

(under subclass 120) Subject matter including means to preheat the principal heating means of the furnace to a temperature for rendering the heating means electrically conductive.