Patent ID: 8264361
Filing Date: 2012-09-11
Classification: G01P,H01H,Y10T

Abstract:
1. 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 inner piston cylinder extending between and communicating with said inlet port and said outlet port so as to facilitate passage of a fluid therebetween; (b) a piston carrying a seal within said piston cylinder and being movable in sealed relation against an inner wall surface thereof between a resting position and a position where a switch is first activated in response to the presence of said fluid flowing through said piston cylinder, said piston being constructed to block free flow of said fluid between said inlet port and said outlet port when positioned between said resting position and said position where said switch is first activated; (c) said switch being operatively disposed for activation upon movement of said piston to said position where said switch is first activated; (d) a vent hole extending through said piston to facilitate controlled dissipation of said fluid through said piston and the return of said piston to said resting position upon a stoppage of said fluid flowing through said piston cylinder; and (e) a piston biasing member carried within said piston cylinder for urging said piston toward said resting position upon a stoppage of said fluid flowing through said piston cylinder.