Integral in tank vent construction for pressure based level monitors

A tank monitor apparatus, for a closed tank having a peripheral wall thereof defining an interior of the tank and a tank opening passing through the peripheral wall, the tank monitor apparatus comprising:

• a tank monitor housing, and a submersible differential pressure sensor;
• the tank monitor housing having a peripheral wall thereof defining a closed interior cavity of the monitor and a sealing closure for the tank opening, with the closure including a closure wall defining and separating a tank-facing surface thereof from a monitor-interior-cavity-facing surface thereof, with the tank-facing surface configured for partially bounding the interior of the tank when the closure is sealing the tank opening, and the cavity-facing surface partially bounding the interior cavity of the monitor;
• the submersible differential pressure sensor including a sensor module disposed outside of the interior cavity of the monitor and a pressure reference tube extending from the sensor module;
• the pressure reference tube having an imperforate wall thereof extending from a distal end to an opposite, open, vented end of the reference tube, with the distal end of the reference tube being operatively joined to the sensor module and the vented end thereof being fixedly attached to the closure of the monitor housing, for providing fluid communication between the vented end of the pressure reference tube and the sensor module;
• the pressure reference tube passing sequentially through the closure wall and into the interior cavity of the monitor, at a first juncture of the reference tube and the closure wall, and then passing back out of the interior cavity of the monitor through the closure wall, at a second juncture of the pressure reference tube and the closure wall, with the open, vented end of the reference tube being disposed outside of the closure wall adjacent the second juncture of the reference tube and the closure wall.