US PATENT SUBCLASS 166 / 60
.~ Electrical heater in well

Current as of: June, 1999
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166 /   HD   WELLS

57  DF  WITH HEATING, REFRIGERATING OR HEAT INSULATING MEANS {5}
60.~ Electrical heater in well

DEFINITION

Classification: 166/60

(under subclass 57) Devices comprising electrical heating means situated below ground level.

SEE OR SEARCH CLASS

175, Boring or Penetrating the Earth,

16, for processes or apparatus of boring by directly applying electrically produced heat to fluidize or comminute the earth formation.

219, Electric Heating,

277+, for electrical oil well heaters, per se. See the class definition of Class 166 for the line.