JPH0544481Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a steam seal structure employed in a connection part of a device that uses high-temperature, high-pressure steam, such as a steam turbine.

[Conventional technology]

Conventionally, as equipment for steam turbines that use high-temperature, high-pressure superheated steam, for example, at the connection between a steam strainer casing installed in the main steam pipe and a lid that closes the opening, there is one side between the two. When fixing the lid to the steam strainer casing by defining a cylindrical space whose end face is wedge-shaped, a ring-shaped packing having a cross-sectional shape approximately the same as that of the space is inserted therein. This force is transmitted to the gasket to bring the gasket into close contact with the peripheral wall of the space, thereby preventing leakage of steam.

As this packing, a ring-shaped metal packing having a cross-sectional shape substantially the same as the cross-section of the space has been used.

This will be explained below based on the drawings. FIG. 5 is a longitudinal sectional view of the steam strainer, and FIG. 6 is an enlarged view of part B thereof. In the figure, 10 is a steam strainer casing (hereinafter referred to as casing) which has a T-shaped tube shape, the upper opening of which is the steam outlet 12, the side opening 13 which is the steam inlet 11, and the lower opening 13 which is the steam inlet 11. It is designed to be closed by a lid 3 which will be described later. Inside it is a hollow cylindrical container-shaped unit holding part 3a fixed to the lid 3.
A hollow cylindrical strainer unit 1 whose one end is fitted and held and whose both end faces are open is accommodated in the housing. Therefore, the steam flowing in from the steam inlet 11 passes through the mesh of the strainer unit 1 to remove foreign matter mixed in the steam, and flows out to the steam outlet 12 as shown by the arrow.

The lid 3 is formed into a disc shape with a tapered part and a stepped part provided on its outer circumferential surface, and a unit holder for fitting and holding the lower end of the strainer unit 1 into its upper end surface. The portion 3a is fixed, and a plurality of studs 8 are arranged and planted in a circular shape on the lower end surface. Then, it is fitted and fixed into the lower opening 13 of the casing 10 in the manner described below.

That is, a ring groove 4a having a square cross section is cut into the inner circumferential wall of the lower opening 13 of the casing 10, into which a segment ring 4 formed by subdividing the ring having a square cross section into several parts can be fitted. Place the strainer unit 1 on the unit holding part 3a.
Insert the lid 3 fitted and fixed into the casing 10 from the lower opening 13 so that the strainer unit 1 stands upright, so that the outer peripheral surface of the lid 3 and the casing 10
A cylindrical space having a wedge-shaped upper end surface defined between the inner circumferential wall of A metal presser ring 5 is sequentially inserted and held by the segment ring 4 fitted into the ring groove 4a.

Next, a casing 10 is placed around the periphery of the flat ring.
A flat plate ring 2a is provided with a cutout portion 26 for fitting into the lower end open surface 13 of the casing, and a plurality of through holes for passing one end of the stud 8 implanted in the lid 3, and a casing. The outer circumferential upper end surface of the L-shaped notch 2d, where the lower corner of the segment ring 4 whose outer circumferential part is fitted into the ring groove 4a of the inner circumferential wall of the lower opening of 10 and whose remaining part protrudes above the inner circumferential wall surface, is abutted. The support ring 2c is placed on the surface of the flat plate ring 2a (top surface in the figure) so that both are concentric and their notches are in the same direction.
The retaining ring 2 joined to the lower end surface of c is inserted into the lower opening 13 of the casing 10, and the lower corner of the segment ring 4 is placed on the notch 2d to support it, and the retaining ring 2 is inserted through the through hole of the flat ring 2a. By screwing the nut 9 into the stud 8 planted on the protruding lid 3 and tightening it, the lid 3 interposes the metal packing 14 and the presser ring 5 between the segment ring 4 and the lid 3. The casing 10 is held and fixed by the segment ring 4 so as to be pulled toward the lower end thereof.

In this way, the casing 10 and the lid 3 are integrated, and the tightening force applied by the metal packing 14 allows them to come into close contact with the opposing wall surface, and the degree of adhesion is further increased by the steam pressure flowing inside the casing 10. This prevents steam from leaking from the connection between the lid 3 and the casing 10.

[Problem that the invention attempts to solve]

As explained above, when using a metal gasket with a wedge-shaped top for steam sealing,
Although it has the advantage of concentrating the force applied to the wedge-shaped part and improving the sealing performance, there is a risk of damaging the contact surface of the other side (in this case, the lid 3 and the casing 10). etc., must be coated on the wedge-shaped part of the metal gasket, which increases manufacturing costs.Also, in the case of metal gaskets, the tip of the gasket must be made to yield, which causes problems such as fatigue and leakage over time. However, there were problems such as high maintenance costs, such as having to make a new one when reassembling it during periodic inspections.

The object of the present invention is to provide an inexpensive steam seal structure that does not leak due to fatigue over time and has a sufficient sealing effect.

[Means for solving problems]

The present invention relates to a reinforced graphite packing formed by covering a cylindrical wedge-shaped cylindrical shape with one end surface inclined, and covering the wedge-shaped top with a tangled body made of thin metal wires; A ring-shaped graphite packing with a rectangular cross section that is molded at a high density of 1.5 times or more than the packing and a presser ring that is a ring with a square cross section are placed in the space defined at the connection between the casing and the lid. An eye packing, a high-density graphite packing, and a presser ring are inserted in this order to form a packing part, and a part of the packing part is fitted into a ring groove provided on the inner circumferential wall surface of the casing opening to hold it; The whole is held by a segment ring projecting above the peripheral wall surface, and is further attached to a stud planted on the outer bottom surface of the lid via a retaining ring whose outer peripheral edge is supported by the end surface of the casing opening. By screwing the nut together, the lid is held by the segment ring, and the tightening force of the nut screwing is applied to the packing part to maintain the steam sealing force, thereby achieving the above purpose. be.

[Effect]

The present invention has a cylindrical space having a wedge-shaped top defined at the connection between the lid 3 and the lower opening 13 of the casing 10, and a cylindrical space having a wedge-shaped shape with one end surface inclined. A reinforcing graphite packing is formed by covering the periphery of the wedge-shaped top with a tangled body made of thin metal wires, and a ring-shaped graphite with a square cross section is formed with a density more than 1.5 times that of the reinforced graphite packing. The packing part consisting of the eye packing and the retaining ring, which is a ring with a square cross section, is replaced, and it is held by a segment ring fitted into the ring groove of the casing, and the lid is closed by tightening bolts through the retaining ring. By holding the segment ring in place, the elasticity of graphite at high temperatures and the steam pressure flowing through the steam strainer concentrate on the wedge part, and the lid, reinforcing graphite packing, and high-density graphite In addition to increasing the degree of adhesion with the gasket, the characteristics of the gasket, such as horizontal expansion, are effectively utilized to improve sealing performance.

〔Example〕

Embodiments to which the present invention is applied will be described below based on the drawings.

Fig. 1 is a longitudinal cross-sectional view of a steam strainer having a cylindrical steam seal portion with one end face shaped like a wedge; Fig. 2 is an enlarged view of section A in Fig. 1;
4 are partial perspective views of a reinforced graphite packing and a ring-shaped graphite packing. Note that the same parts as in the conventional example shown in FIGS. 5 and 6 are given the same reference numerals, and explanations of the overlapping parts will be omitted.

In Figures 1 to 4, 6 is a reinforced graphite packing, as shown in Figure 3.
The graphite cylinder consists of a cylindrical body 6a which is compression molded into a cylindrical shape with one end surface exhibiting a wedge shape, and a cloth tape-like entangled body 6b knitted with thin metal wires, such as stainless steel wires. It is integrally formed by covering the wedge-shaped top of 6a with a tangled body 6b. In addition, the ring-shaped graphite packing 7 is a ring with a rectangular cross ^section as shown in FIG.
It is formed to have a bulk density of 1.6 to 2.1 gr/cm ² .

The above-mentioned reinforcing graphite packing 6 and ring-shaped graphite packing 7 are constructed by inserting the strainer unit 1 into the inside of the casing 10 and inserting the lid 3 into the casing via the segment ring 4 in order to close the lower opening 13 of the casing 10. In order to prevent leakage of steam from the contact portion between the lid 3 and the casing 10 when the lid 3 is fixed to the inner circumferential surface of the casing 10, a packing portion is formed together with the presser ring 5. That is, it is located and formed under the contact portion between the lid 3 and the casing 10. First, a reinforcing graphite packing 6 is inserted into a cylindrical space with a wedge-shaped upper part and an open lower part so that its top fits into the wedge-shaped part of the space, and then a ring-shaped graphite packing 6 is inserted The gasket 7 is inserted, and the presser ring 5 is further inserted to fill the space and form the gasket part.

In this way, the packing part filling the space between the lid 3 and the casing 10 is attached to the casing 10.
Ring groove 4a provided in the lower opening 13 of
into the lower opening 1 of the casing 10 and partially into the lower opening 1 of the casing 10
Segment ring 4 protruding from the inner wall surface of 3
At the same time, a plurality of studs 8 planted on the lower end surface of the lid 3 are made to pass through the bolt holes arranged in the retainer ring 2 and protrude below the retainer ring 2, and a nut 9 is screwed into the studs 8. By fitting and tightening, the lid 3 is pulled toward the lower end surface of the casing 10 through the retainer ring 2 and held by the segment ring 4, and the lower opening 13 of the casing 10 is airtightly closed by the lid 3. Let it happen.

By tightening in this manner, initial tightening surface pressure is applied to both the reinforcing graphite packing 6 and the ring-shaped graphite packing 7 that are inserted between the lid 3 and the segment ring 4 via the presser ring 5. The force causes both to expand in the horizontal direction and fit into the walls of the lid 3 and the casing 10 and come into close contact with them. Therefore, when steam is vented, steam pressure acts on the lid 3, which acts on the wedge-shaped portion of the reinforced graphite packing 6, making the sealing performance even more effective.

After the initial ventilation, the nut 9 is tightened again to apply tightening surface pressure to both the gaskets 6 and 7 to completely prevent steam leakage from the steam strainer.

[Effect of idea]

As explained above, according to the present invention, in the cylindrical space defined at the connection between the casing and the lid, a reinforced graphite packing whose wedge-shaped top is protected by an intertwined body, and a high-density ring-shaped A graphite packing and a metal retaining ring are inserted in this order to form a three-layer packing part, and the packing part is held by a segment ring that is partially fitted into the inner circumferential wall of the lower opening of the casing. At the end of the opening, screw the nut onto the planted stud via the retainer ring, pull the lid downward, and hold it with the segment ring to create surface pressure for steam sealing. It is retained. In particular, by using a high-density graphite ring in the middle of the packing part, it is possible to increase the graphite's resistance to oxidation and to exhibit elasticity at high temperatures, thereby improving sealing performance.

Therefore, compared to conventional metal packings, most of the packing parts that contact the inner wall of the casing and the outer circumferential surface of the lid are made of soft graphite, so they do not damage the other party, and the cost is also significantly lower than that of conventional ones. In addition, since the tip of the packing part does not undergo plastic deformation, it can be reused and maintenance costs can be reduced, making it possible to provide an extremely economical steam seal structure.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a steam strainer casing according to an embodiment of the present invention, Fig. 2 is an enlarged view of section A in Fig. 1, and Figs. 3 and 4 are the reinforced graphite packing and A partial perspective view of a ring-shaped graphite packing; FIG. 5 is a vertical cross-sectional view of a steam strainer casing using a conventional packing;
FIG. 6 is an enlarged view of section B in FIG. 2... Retainer ring, 3... Lid, 4... Segment ring, 5... Holder ring, 6... Reinforced graphite packing, 7... Ring-shaped graphite packing, 8... Stud, 9... Nut, 10...
...Steam strainer casing (casing), 1
4...Metal packing.

Claims (1)

[Scope of utility model registration request] In order to seal the connection between the casing of the device through which steam flows and the lid that closes the opening of the casing, one end surface formed at the connection has an inclined wedge shape. In a steam seal structure in which a gasket is enclosed in a cylindrical space, the cylindrical shape has a wedge shape with one end surface slanted, and the tangled body made of thin metal wires is formed around the top of the wedge shape. A reinforced graphite packing formed by covering the reinforcing graphite packing, a ring-shaped graphite packing formed with a high density of 1.5 times or more than the reinforced graphite packing and having a rectangular cross section, and a presser ring which is a ring with a rectangular cross section are placed in the space. A reinforcing graphite packing, a ring-shaped graphite packing, and a presser ring are inserted in this order to form a packing part, and the packing part is partially fitted into a ring groove provided on the inner peripheral wall surface of the casing opening. The remaining portion is held by a segment ring projecting above the peripheral wall surface, and the outer bottom surface of the lid is further held by a retaining ring whose outer peripheral edge is supported by the end surface of the casing opening. By screwing a nut onto the planted stud, the lid is held by the segment ring, and the tightening force of screwing the nut acts on the packing part to maintain steam sealing power. A steam seal structure characterized by: