US PATENT SUBCLASS 392 / 306
.~.~ Plural separate heating devices

Current as of: June, 1999
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392 /   HD   ELECTRIC RESISTANCE HEATING DEVICES

*  DD  HEATING DEVICES (CLASS 219 SUBCLASS 200) {11}
301  DF  .~ Borehole type {5}
306.~.~ Plural separate heating devices

DEFINITION

Classification: 392/306

Plural separate heating devices:

(under subclass 301) Subject matter wherein the borehole contains two or more heating devices spaced from one another so that heating devices can heat different portions of the borehole.