(under subclass 57) Devices comprising pump or plunger means in the well for drawing well fluids out of the well or into a receptacle which is lifted out of the well.
(1) Note. Devices in which a heated fluid is conveyed into the well so as to act as both a heating and a lifting means are not considered to be pumps for this subclass. Such devices may be found in subclass 57.
SEE OR SEARCH THIS CLASS, SUBCLASS:
61, for well devices comprising a heater surrounding a pump production tube.
