| 摘要 |
<p>A well instrument is isolated from the high temperatures of a surrounding earth formation by enclosing the instrument within a heat insulative jacket structure, preferably a dewar having spaced walls with a vacuum therebetween, with a heat sink contained in the jacket above the instrument assembly, and with a heat pipe extending upwardly from the instrument assembly to the heat sink and containing a fluid which by evaporation at a lower point and condensation at a higher point will conduct heat upwardly from the instrument assembly to the heat sink but not downwardly therebetween. The heat pipe preferably projects upwardly beyond a top portion of the insulating jacket to the location of a convector element which is exposed to the temperature of fluid or air at the outside of the insulating jacket to transmit heat from within the jacket to its exterior but not in a reverse direction.</p> |
