Patent ID: 8264360

Claim:
A fluid flow switch for detecting exceptionally low rates of fluid flow, comprising: (a) a housing having an inlet port, an outlet port and an interior piston chamber extending between and communicating with said inlet port and said outlet port; (b) a gravity-induced piston carried within said piston chamber, said piston being movable along an axis within said piston chamber from a resting position to a switch-activating position in response to the presence of fluid flowing through said piston chamber, and being returned to said resting position under the force of gravity in the absence of fluid flowing through said piston chamber; (c) a switch operatively disposed for activation upon movement of said piston to said switch-activating position; and (d) a piston biasing member carried by said housing in axial alignment with said piston on said axis and being adapted to draw said piston against the force of gravity toward said switch-activating position in order to increase sensitivity of said piston when fluid flows through said piston chamber.