| 主权项 |
1. A dual sensor head assembly to provide signals to a signal processor, the signal processor being configured to compare signals from the sensors to provide indication of defect when the sensor signals do not match, to provide a normal operation indication when both sensor signals match and each sensor signal indicates normal fluid flow or liquid level in the sensed media, and to provide an alarm indication when both sensor signals match and each sensor signal indicates an alarm condition in the sensed media and for other signal processing purposes, the sensor head assembly comprising:
a sensor head having a flange for mounting in a fluid flow conduit wall or in a liquid container wall, said sensor head having a distal end configured to be located outside the conduit or container; circuit boards in said sensor head, said circuit boards being configured to connect independent ΔR output signals to the signal processor; a housing on the proximal end of said sensor head and configured to extend into the interior of the conduit or container; a first thermowell extending generally axially from the proximal end of said sensor head, said first thermowell having two independent reference sensor elements therein; a second thermowell extending from said sensor head generally parallel with on first thermowell, said second thermowell having a first sensor element and a first heater element therein for heating said first sensor element; a third thermowell extending from said sensor head generally parallel with said first and second thermowells, said third thermowell having a second sensor element and a second heater element therein for heating said second sensor element; and signal wires connecting said reference sensors, active sensors, and heater elements to said circuit boards to develop independent ΔR signals front said first and second active sensors. |
