(under subclass 290) Gauges having a tube so mounted in the reservoir that one end is movable with respect to the liquid level and the other end is connected to the exterior of the reservoir. Determination of liquid level is accomplished by adjustment of the tube to a position wherein "flow" or "no-flow" conditions through the exterior connection are
produced by slight movement in either direction.
SEE OR SEARCH CLASS
210, Liquid Purification or Separation,
513+, for similar structure employed for decanting.
