Fluid switch

A fluid switching element comprising:

• a housing formed of first and second members defining a cavity therebetween and having a pair of ports, one of said ports having a fluid pressure applied thereto, said housing having a venting port for enabling said cavity to communicate with ambient;
• a conduit disposed within said housing and extending between said ports for fluid to flow therethrough, the diameter of said conduit being of sufficient dimension with the pressure and viscosity of said fluid such that laminar flow occurs, said conduit having a gap therein determined by said cavity and across which said fluid flows in laminar flow;
• a piston disposed in said cavity in the absence of separate sealing means and having a transverse channel selectively alignable with said conduit, said piston being biased to a quiescent position and being actuated to a displaced position, one of said quiescent and displaced positions having said channel in alignment with said conduit;
• and
• a lever pivotally mounted in said housing and having an actuating head externally of said housing for receiving a minimum actuation force to swing said lever about said pivot mount and thereby exert a force on said piston to displace same from said quiescent position to said displaced position.

A fluid switching element comprising:

• a housing formed of first and second members defining a cavity therebetween and having a pair of ports, one of said ports having a fluid pressure applied thereto, said housing having a venting port for enabling said cavity to communicate with ambient;
• a conduit disposed within said housing and extending between said ports for fluid to flow therethrough, the diameter of said conduit being of sufficient dimension with the pressure and viscosity of said fluid such that laminar flow occurs, said conduit having a gap therein determined by said cavity and across which said fluid flows in laminar flow;
• a piston disposed in said cavity in the absence of separate sealing means and having a transverse channel selectively alignable with said conduit, said piston being biased to a quiescent position and being actuated to a displaced position, one of said quiescent and displaced positions having said channel in alignment with said conduit;
• and
• an actuator responsive to a minimum actuation force to thereby exert a force on said piston to displace same from said quiescent position to said displaced position, said actuator including electromagnetic means for causing said piston to displace when energized.

A fluid switch, comprising:

• a housing having a cavity therein;
• at least one inlet port and at least one outlet port in said housing, said inlet port receiving fluid of predetermined kinetic viscosity and pressure;
• an inlet conduit in said housing coupled at one end to an inlet port through which fluid flows in response to said pressure, said inlet conduit having a predetermined diameter to permit said fluid having said predetermined kinetic viscosity and pressure to flow therethrough in laminar flow;
• an outlet conduit in said housing aligned with said inlet conduit and coupled at one end to an outlet port, said outlet conduit having said predetermined diameter, said inlet and outlet conduits having respective other ends communicating with said cavity and spaced from each other by a gap defined by said cavity, said gap being less than that wherein said laminar flow changes to turbulent flow;
• a piston movable in said cavity in response to a force exerted thereon and having a transverse channel therethrough, said channel having said predetermined diameter, and said piston being movable to selectively align said transverse channel with said inlet and outlet conduits so that said laminar flow passes therethrough, said piston having one wall through which said transverse channel passes, said one wall being slidable along the wall of said cavity to selectively block said inlet conduit, and said piston having a boss on another wall opposite to said one wall and through which said transverse channel passes, said boss being of limited dimension and slidable along the wall of said cavity to selectively position said transverse channel therein in alignment with said outlet conduit, said piston additionally having an upper edge and a lower shoulder;
• said cavity being provided with a first shoulder to contact said piston upper edge and a second shoulder to contact said piston lower shoulder, thereby to determine the selective alignment of said transverse channel with said inlet and outlet conduits;
• and
• means for exerting a force on said piston to selectively urge said upper edge against said first shoulder and said lower shoulder against said second shoulder.