Thermal barrier for downhole flasked electronics

Abstract

Apparatus including an assembly associated with a downhole tool and configured to thermally isolate a thermally sensitive component. Components of the assembly include a thermal housing; a chassis interior to the thermal housing; at least one thermally sensitive component mounted on the chassis; and a thermal isolation support connecting the chassis to the tool. The thermal isolation support comprises an elongated thermal isolator having a first end and a second end opposite the first end, the thermal isolator connected to the tool at the first end and connected to the chassis at the second end, and a heat sink thermally coupled to the elongated thermal isolator at the second end. The second end of the elongated thermal isolator may comprise the only points of thermal coupling between the heat sink and the components other than the heat sink.

What is claimed is: 
     
         1 . An apparatus for use in a borehole intersecting an earth formation, the apparatus comprising:
 an assembly associated with a downhole tool and configured to thermally isolate a thermally sensitive component, the assembly comprising components including:
 a thermal housing; 
 a chassis interior to the thermal housing; 
 at least one thermally sensitive component mounted on the chassis; 
 a thermal isolation support connecting the chassis to the tool, wherein the thermal isolation support comprises:
 an elongated thermal isolator having a first end and a second end opposite the first end, the thermal isolator connected to the tool at the first end and connected to the chassis at the second end, and 
 a heat sink thermally coupled to the elongated thermal isolator at the second end. 
 
   
     
     
         2 . The apparatus of  claim 1 , wherein the second end of the elongated thermal isolator comprises the only points of thermal coupling between the heat sink and the components other than the heat sink. 
     
     
         3 . The apparatus of  claim 1 , wherein a center of mass of the heat sink is oriented further from the thermally sensitive component than the second end. 
     
     
         4 . The apparatus of  claim 1 , wherein the heat sink is elongated and comprises:
 a coupled end coupled to the second end of the elongated thermal isolator, and   a decoupled end opposite the coupled end, the decoupled end thermally decoupled from the elongated thermal isolator.   
     
     
         5 . The apparatus of  claim 4 , wherein the decoupled end is oriented further from the thermally sensitive component than the coupled end. 
     
     
         6 . The apparatus of  claim 4 , wherein the decoupled end is located proximate the first end of the elongated thermal isolator. 
     
     
         7 . The apparatus of  claim 1 , wherein the elongated thermal isolator comprises a sleeve. 
     
     
         8 . The apparatus of  claim 1 , wherein the heat sink is interior to the elongated thermal isolator. 
     
     
         9 . The apparatus of  claim 1 , wherein a length of the heat sink is substantially the same as a length of the elongated thermal isolator. 
     
     
         10 . The apparatus of  claim 1 , wherein the heat sink is a substantially solid cylinder. 
     
     
         11 . The apparatus of  claim 1 , wherein the at least one thermally sensitive component comprises at least one downhole electronic component. 
     
     
         12 . The apparatus of  claim 1 , wherein the chassis is supported substantially exclusively by the thermal isolation support. 
     
     
         13 . The apparatus of  claim 1 , wherein the heat sink is thermally coupled to the elongated thermal isolator only at the second end. 
     
     
         14 . The apparatus of  claim 1 , wherein the elongated thermal isolator comprises a mesh tube of connected members. 
     
     
         15 . An apparatus for use in a borehole intersecting an earth formation, the apparatus comprising:
 an assembly associated with a downhole tool and configured to thermally isolate a thermally sensitive component, the assembly comprising components including:
 a thermal housing; 
 a chassis interior to the thermal housing; 
 at least one thermally sensitive component mounted on the chassis; 
 a thermal isolation support connecting the chassis to the tool, wherein the thermal isolation support comprises:
 an elongated thermal isolator having a first end and a second end opposite the first end, the thermal isolator connected to the tool at the first end and connected to the chassis at the second end, and 
 wherein the elongated thermal isolator comprises a mesh tube of connected members. 
 
   
     
     
         16 . The apparatus of  claim 15 , wherein the thermal isolation support comprises a heat sink thermally coupled to the elongated thermal isolator at the second end. 
     
     
         17 . The apparatus of  claim 15 , wherein a majority of the connected members of the mesh tube are substantially non-parallel with a longitudinal axis of the downhole tool.