LIQUID LEVEL DETECTION

摘要

A method and apparatus for detecting the presence of a liquid level at a monitor point along the depth of a borehole utilizes a diaphragm pressure switch for sensing the pressure of a captive air column in a measurement tube extending from the pressure switch to a predetermined point below the monitor point. In use, a rising liquid level in the borehole seals off the open lower end of the measurement tube from the earth atmosphere and allows the rising liquid level to compress the captive air column. In a preferred embodiment a visual signal is activated by the pressure switch when the rising liquid level in the borehole reaches the monitor point.