Temperature sensor

A temperature sensor characterized by:

• a probe adapted for placement at a location the temperature of which is to be measured, said probe containing a reservoir of a first fluid and a first bellows responsive to the pressure of said first fluid;
• and
• a chamber portion thermally isolated from said probe and including therein:
• a valve comprising a first movable header connected to said first bellows and a stationary nozzle,
• means connecting said valve to said first bellows for operation thereby:
• a first conduit for channeling a second fluid through said valve, adjustments in the setting of said valve by said first bellows effecting corresponding adjustments in the pressure of said second fluid indicative of variations in said measured temperature;
• a jacket in fluid communication with said valve, flow of said second fluid through said jacket maintaining said connecting means at a uniform temperature for minimization of differential expansion thereof and insulation thereof from variations in ambient temperature;
• said chamber portion including a second fluid conduit providing fluid communication between said nozzle at an outlet thereof and said jacket;
• and
• a second movable header fixed to said connecting means, said second header being in fluid communication with said second fluid conduit, said second fluid conduit channeling said second fluid to said second header for pressurization thereof in a direction opposite that of the pressurization of said first header.