Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

PRESSURE transducers can be used to sense water depths in open channel flow measurement devices. In the low pressure range, the water-air interface must be eliminated by purging air from the system or the interface must be carefully controlled. Submersible transducers can be fitted with an air vent tube to allow automatic air purging. A portable bubbler system, which maintains the interface at the pressure tap, can be made from a propane filled bottle, a pressure regulator, and a snubber fitting. A pressure cell with a large air-water interface-to-air volume can transmit water pressure to a sensor through a trapped air volume with minimal reference elevation fluctuation.