Low level indicator

Claim 1

In a device wherein a liquid is drawn from a reservoir of said liquid by means of a pump, a low level warning device comprising in combination: a. a suction line dipping into the liquid in a reservoir from which a quantity of liquid is to be withdrawn, b. a diaphragm opposite a central chamber in said line, the entire surface of said diaphragm being directly in the line of flow of said liquid whereby liquid flows in direct turbulent contact across the surface of the diaphragm and there is no constriction between said line and said diaphragm, c. a switch actuated by said diaphragm, said diaphragm being drawn in when suction is placed on said line and liquid is in said reservoir and said diaphragm moving out when a column of liquid is not maintained below said diaphragm whereby d. outward movement of said diaphragm actuates a switch and said switch actuates a warning device, and stop means in said central chamber opposite said diaphragm for preventing excessive excursions of said diaphragm and for promoting liquid turbulence across said diaphragm.