(57) A rotary, positive displacement progressing cavity pump comprising a stator (4),
a rotor (5) within the stator, an inlet and outlet in the stator and a drive shaft
(6) connected to the rotor, the drive shaft-to-rotor connection (12,13) comprising
a heat-sensitive, breakaway bond (14) of a heat-fusible metal alloy in an amount to
provide a metchanical linkage between the drive shaft and the rotor, the metal alloy
being meltable upon the generation of heat within the pump cavity and so disconnect
the mechanical linkage.
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