A through-hole sealing device capable of sealing a through hole through whicha pipe is passed with a simple structure even if a pressure difference islarge, wherein a plurality stages of gland packings (26) are arranged on theouter periphery of a pipe (21), the gland packings (26) are pressed radiallyinwardly by tubes (24) through retainers (30), the tubes (24) press the glandpackings (26) against the outer peripheral surface of the pipe (21) by thepressure of a tightening gas fed through tightening gas access ports (31), theplurality stages of the tubes (24) and the gland packings (26) are held byring spacers (30) and an outer tube (25), the pressing force of the glandpackings (26) in sliding contact with the outer peripheral surface of the pipe(21) can be regulated easily by the regulation of the pressure inside thetubes (24), and a sealing performance can be increased easily with a simplestructure.
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