| 摘要 |
Apparatus for measuring barometric pressure comprising a housing made of high thermal conductivity metal and defining a cavity therein, a diaphragm of flexible spring type material clamped in position across the cavity dividing it into upper and lower portions, a connecting passage leading from the lower portion of the cavity to the pressure to be measured, electrical means for measuring deflections of the diaphragm and providing a control signal to a power supply, a low boiling point liquid filling part of the upper portion of the cavity in the housing, with vapor from the liquid filing the remaining part, a heating coil positioned in relation to the housing and connected to the power supply controlled by the electrical means such as to bring the temperature of the liquid and thus its vapor pressure to a level to balance the pressures across the diaphragm, thermal insulation encompassing the housing and means for measuring the temperature of the housing and the liquid therein, this temperature being related to the pressure being measured.
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