Device for detecting the presence of flow of a fluid

The alarm mechanism of the invention signals the absence of a liquid from a source of aqueous liquid. The alarm mechanism comprises an alarm body having an inlet port and an outlet port; the inlet port in liquid communication with a source of liquid, the outlet port in liquid communication with a use locus. The alarm mechanism additionally comprises a float chamber placed in liquid parallel communication with the inlet port and the outlet port. The float chamber contains a float operably connected to a mechanical alarm. The float, as the chamber is emptied of liquid, reaches a position wherein a "low or empty product" signal is generated. The apparatus operates by passing liquid through the body. As liquid in the source of liquid is depleted and is no longer available for passage through the body, the body becomes emptied of liquid as the source of pressure removes liquid from the body and particularly from the chamber causing the float to reach a position generating a signal.