Thermal mass flow sensor having low thermal resistance

A thermal mass flow measuring apparatus comprising:

• a stainless steel sheath having an interior surface and a protective exterior surface;
• liquid metal disposed within the stainless steel sheath and contacting the interior surface thereof,
• a seal disposed within the stainless steel sheath for containing the liquid metal;
• a sensor element at least partially submerged in the liquid metal;
• and
• sensor leads electrically connected to the sensor element.

A thermal mass flow measuring apparatus comprising:

• a sheath having an interior surface and a protective exterior surface;
• a sensor element disposed within the sheath;
• and means for providing a thermal path between the sensor element and the interior surface of
• the sheath, the means for providing a thermal path having a thermal conductivity greater than about 12 w/(m·° C.) and having substantially no air gaps between the sensor element and the interior surface of the sheath.

A thermal mass flow measuring apparatus comprising:

• a sheath having an interior surface and a protective exterior surface;
• a sensor assembly insert disposed at least partially within the sheath, the sensor assembly insert comprising:
• a sensor element for sensing temperature characteristics;
• sensor leads connected to the sensor element;
• an elongate preform surrounding and supporting the sensor leads;
• an elongate protective sleeve surrounding the preform;
• and
• a sealer material disposed between the protective sleeve and the sensor leads at one end of the protective sleeve and disposed between the protective sleeve and the sensor element at an opposing end of the protective sleeve.
• a filler material disposed within the sheath between the sensor element and the interior surface of the sheath