Shaft-seal device for high-temperature fluid

摘要

A shaft-seal device for high-temperature fluid including a seal case (2) formed as a metallic cylindrical structure of a single unit and comprised of a main body portion (2a, 2b, 2c), first and second holding portions (2d, 2e), first and second partition portions (2f, 2h), a channel formation portion (2g) forming a minute annular channel (27) with the outer circumference surface of a rotary shaft (1), and an o-ring holding portion (2i). The seal case is installed in an apparatus housing (8) with first and second o-rings (2m, 2n) in between. The intra-seal case region (A1), in which sealing rings (31, 32, 41, 42, 51, 52) of mechanical seals (3, 4, 5) are provided, and the high-temperature fluid region, which is an intra-apparatus housing region (A), are partitioned by a cooling chamber (28) into and from which coolant (82) is supplied and discharged via feed/discharge coolant paths (80, 81).

主权项

1. A shaft-seal device for high-temperature fluid having a primary seal, a secondary seal, and a tertiary seal disposed at equal intervals to form a mechanical seal in a seal case installed in an apparatus housing,
the mechanical seal exhibiting a sealing performance through a relative rotation effect between sealing end-faces that are facing end-faces of:
rotational sealing rings fixed to a rotary shaft passing through the seal case, andstationary sealing rings fit and held in the seal case with O-rings in between and facing the rotational sealing rings in a displaceable manner in an axis direction of said rotary shaft, and seal water whose pressure is lower than a fluid pressure of an intra-apparatus housing region being circulated and supplied to each of a first sealed space formed between the primary seal and the secondary seal and a second sealed space formed between the secondary seal and the tertiary seal, wherein the seal case takes a metal structure comprising
a main body portion that is a cylindrical body,a first holding portion that is a cylindrical body, extending from an inner-circumference edge portion of an end portion of said main body portion toward an intra-apparatus housing region direction as a single unit,a second holding portion that is an annular plate, extending from an end portion of the first holding portion in a radial direction inwardly as a single unit,a first partition portion that is an annular plate, extending from an inner-circumference end portion of the second holding portion in a radial direction inwardly as a single unit,a channel formation portion that is a cylindrical body extending from an inner-circumference end portion of the first partition portion in an intra-apparatus housing region direction as a single unit and forms a minute annular channel between an outer circumference surface of said rotary shaft,a second partition portion that is an annular plate, extending from an end portion of the channel formation portion toward a radial direction outwardly as a single unit, andan O-ring holding portion that is an annular plate extending from an outer-circumference end portion of the second partition portion in a radial direction outwardly as a single unit and has an outside diameter coincide with the main body portions; and wherein the seal case is fitted in the apparatus housing in a state in which first and second O-rings are interposed between inner- and outer-circumference edge portions of the O-ring holding portion and a sealing member of the apparatus housing, a cooling chamber is provided as an indentation formed between main body portion and the O-ring holding portion and closed by a feed and discharge path formation portion set up in the apparatus housing, a coolant is supplied to and discharged from the cooling chamber through feed/discharge coolant paths formed in the feed and discharge path formation portion, and an intra-seal case region, in which said sealing rings are provided, and a high-temperature fluid region, which is an intra-apparatus housing region, are partitioned by a cooling chamber section that is an inner-circumference section of said cooling chamber and surrounded by both partitioned sections and the channel formation portion, and said shaft-seal device further comprises a first water feed/discharge means for circulating and supplying the seal water to the first sealed space and a second water feed/discharge means for circulating and supplying the seal water to the second sealed space, each of which being comprised of
a feed water path formed in the main body portion of the seal case,a discharge water path formed in said main body portion,an annular feed water channel formed in an inner-circumference surface of said main body portion and communicating with the feed water path,an annular discharge water channel formed on an inner-circumference surface of said main body portion and communicating with the discharge water path,a shower ring installed in an inner-circumference surface of said main body portion to close and seal openings of the feed/discharge water channels,feed water holes that are multiple through-holes communicating with a feed water channel and provided in the shower ring at equal intervals in a circumferential direction thereof, anddischarge water holes that are multiple through-holes communicating with the discharge water channel and provided in the shower ring at equal intervals in a circumference direction thereof; and each of the first and second water feed/discharge suppresses a pulsing phenomenon of the seal water accompanying a supply and circulation in the sealed space by
supplying the seal water supplied from the feed water path to the feed water channel to all feed water holes in the sealed space, anddischarging the seal water in the sealed space from all discharge water holes to the discharge water path through the discharge water channel, and wherein in the second water feed/discharge means,
the feed water holes are provided facing an outer-circumference surface of one of the rotational and stationary sealing rings in the tertiary seal, andthe discharge water holes are provided facing an outer-circumference surface of another one of the rotational and stationary sealing rings in the tertiary seal.