Patent ID: 6887048

Claim:
A liquid pump assembly, comprising: a motor casing for an electric motor having a cylindrical frame; a rotating motor shaft extending from said casing; a rotary base member fixed to said rotary shaft and having a lower surface; a pump casing attached to said cylindrical frame and having a pump chamber enclosed in a watertight manner by said cylindrical frame; a vertically sliding member between said rotary base member and said pump casing, and having an upper surface; an impeller fixed to a tip of said rotating shaft and located in said pump chamber; and a sealing mechanism disposed in an air chamber between said motor casing and said pump casing, said sealing mechanism including an annular rotating sealing member and a flexible stationary sealing member disposed around said rotating shaft and including movable and stationary magnets with N-poles and S-poles opening and closing said sealing mechanism by joining and separating said sealing members, respectively, by magnetic force of said magnets, said rotating sealing member being attached to said lower surface of said rotary base member, said stationary sealing member being fixed on said upper surface of said vertically sliding member, said movable magnets being disposed and displaceable in said rotary base member by centrifugal force created by rotation of said rotating shaft and said rotary base member, said stationary magnet being disposed on said upper surface of said vertically sliding member; whereby, when said rotating shaft is stopped, one pole of said movable magnet is in a stopped position adjacent an opposite pole of said stationary magnet to attract and move said vertically sliding member upwardly until upper surface of said flexible stationary sealing member contacts a lower surface of said annular rotating sealing member to seal said air chamber; and whereby said rotating shaft is rotating at least a predetermined number of rotations, said pair of sealing members are controlled so that the same poles of said movable magnet is displaced from said stopped position by centrifugal force, such the pole of said stationary magnet repels the pole of said movable magnet to depress said vertically sliding member downward, and to separate said upper surface of said stationary seal from said lower surface of said annular rotating seal to unseal said chamber.