US PATENT SUBCLASS 392 / 304
.~.~ Heating element surrounding delivery pipe

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}
304.~.~ Heating element surrounding delivery pipe

DEFINITION

Classification: 392/304

Heating element surrounding delivery pipe:

(under subclass 301) Subject matter wherein the heating element encircles an outer surface of a tube inserted into the well for conveying fluid into or out of the well.

SEE OR SEARCH THIS CLASS, SUBCLASS:

468+, for pipeline tracing fluid heater.

472, for flexible hose type fluid heater.

479+, for externally heated line connected section for fluid heater.