The invention discloses a magnetic fluid sealing device for a gasholder. The magnetic fluid sealing device is installed between a
piston of the gasholder and the inner wall of a holder body, and comprises an upper pole shoe, a
lower pole shoe, a permanent
magnet, pole teeth and a magnetic fluid, wherein the upper pole shoe and the
lower pole shoe are of an annular structure respectively, and located on the upper part and the lower part of a disc edge of the
piston respectively, and the upper pole shoe and the
lower pole shoe are both magnetic conductors; the permanent
magnet is clamped between the upper pole shoe and the lower pole shoe, is of an annular structure, and is out of touch with the
piston; the plurality of pole teeth are provided, and arranged on the end parts of the upper pole shoe and the lower pole shoe, a certain gap is kept between the end part of each pole tooth and the inner wall of the holder body, and the magnetic fluid is injected in each gap; the holder body is made of a
metal magnetic conductor material, the piston is made of a non-
metal non-magnetic conductive material, and the magnetic fluid is a magnetic liquid. The sealing device disclosed by the invention is bidirectional, applicable to gas holders with various capacities, simple in structure, high in stability, and convenient to maintain because only the magnetic fluid needs to be regularly supplemented; and with the adoption of the sealing device, the invalid capacity of the
gas holder is small, and the construction cost is greatly reduced.