RU10422U1 - TURBINE SEAL - Google Patents

Abstract

The utility model relates to power engineering, in particular to turbine engineering,

A useful model solves the problem of creating a turbine seal, characterized by high operational reliability with ease of manufacture and operation.

To solve the problem in turbine sealing, we include a housing in which at least one annular groove is made, in which a ring is placed and rigidly fixed, having a protrusion on the outer surface and an antenna on the inner surface, and a protrusion and antenna made of the same material as the ring, it is proposed, according to the present utility model, that the ring is made of a material based on fluoropolymer with one radial section.

RF Mi

Description

UOLOIGMZHSHMZH

The utility model relates to power engineering, in particular to turbine engineering.

As you know, turbines in the places where the shaft exits the housing, between the shaft, the housing and the diaphragms have seals.

Depending on the installation site, three types of seals are distinguished: end (external), over-band and diaphragm.

External seals are designed to reduce leakage of the working fluid (steam, gas) at a pressure above atmospheric, or to prevent the penetration of outside air into the body at a pressure below atmospheric.

Diaphragm seals should prevent leakage through the gap between the diaphragms and the shaft.

End seals are known of three types: coal, water, labyrinth.

Coal seals have gained some popularity on small-capacity turbines in which steam leakage occurs in a narrow shaft; ate between the carbon ring and the sleeve worn on the shaft.Each ring is cut into three to four parts and pulled together by a spring. The carbon rings are installed in the housing so that there is a gap between the ring and the shaft. L.1, p. 165.

11 / t

The rings are placed in a housing (clip), which, in turn,

set in a common box, rigidly connected to the turbine body L. 2, p. 83.

Typically, sealing steam is supplied to the coal seals from the low pressure side 9, which contributes to the rusting of the springs and, consequently, the wear of the rings and the breakdown of the rusted springs.

In this case, spring breakdowns are detected only when several rings fail with a strong suction of air into the condenser, opening the seal reveals a worn shaft neck, which requires grinding and even grooving.

Coal seals of this type required a landing on the shaft of removable alloy steel sleeves, which due to the weakening of the landing are characterized by relatively low reliability L. 2, s. 84.

Labyrinth-coal seals L. 2, p. 85 allowed the initial installation of seals to produce without gaps. The ridges of the bushings, mounted on the shaft, pierced small grooves in the liners, in which the steam is throttled.

However, due to the rapid wear of the liners, labyrinth-coal seals are not widely used in domestic turbine construction.

Water (hydraulic) seals provide complete impermeability with a small length of the device, however, they are associated with the cost of turbine power, which leads to a decrease in efficiency, require increased attention in operation, determined by the ability to work only when the shaft rotates, cannot balance

significant pressure difference. Steam has to be supplied to it, and it is also necessary to replenish with condensate a special make-up tank L. 1, p. 165-167.

Due to the reasons described above, hydraulic seals in combination with labyrinth ones have not found practical application, but I have; in practice, cases of their transfer to the labyrinth seals of the simplest type do not give the expected result and sometimes lead to accidents in the case of seals being seized by bushings mounted on the shaft L .2, p. 85.

The principle of the labyrinth seal is the passage of steam and gas through a series of small gaps, each of which is followed by a relatively large chamber. Passing through small gaps in a zigzag fashion, the steam loses some of the pressure, changes the kinetic energy of the jet to heat, increasing specific volumes and decreasing the speed of vortex motion.

The design of the labyrinth seal is determined

radial gaps and antennae, the number of which is straight along the length

in proportion to the clearance.

All known labyrinth seals are characterized by design complexity, determined by safety conditions due to the impact of the rotor shaft by the seal. At the same time, the problem of deflection of the shaft in operation when the rotor is touched by the seal remains unsolved.

The complication of seal designs, on the one hand, the use of various materials in them to reduce gaps, is sometimes negated by the practice of installation, commissioning and repair of seals, when due to insufficient qualifications of specialists

the gaps instead of the minimum are set to maximum, sharply reduces the efficiency of the turbine.

A labyrinth seal is known, consisting of a housing having recesses, in which there are usually six (three by half) segments of the Christmas tree type, where the antennae are machined for high and medium pressure cylinders along with the rings, and in low pressure cylinders, brass antennae are made from sheet brass L. 3, p. 331.

2 mm thick, stamped antennae after winding into the grooves of the rings are choked and pierced L. 4, p. 78-79. Each o-ring from segments tightly fitted to each other is pressed to the center on the seating surface of the grooves with leaf springs.

Springs should not be too rigid and should

to allow deflection of the segment by hand: and should not be too elastic, since otherwise the correct installation of the rings L, 5, s will not be ensured. 42.

The principle of operation of a seal of any design, both coal and labyrinth, is to provide a minimum vapor pass through a number of small gaps, therefore, the requirements for the reliability of the seal are quite high, and the main task of the developer of such seals is to provide a seal having radial gaps, characterized by ease of assembly, simplicity of repair and ease of disassembly with minimal labor both for the manufacture of seals and for their repair.

manufacturing, as well as the complexity of operation with a relatively low operational reliability.

A useful model solves the problem of creating a turbine seal, characterized by high operational reliability with the simplicity of its manufacture and operation.

To solve the problem in sealing a turbine, the contents of the housing in which at least one annular groove is made, in which a ring is placed and rigidly fixed, has a protrusion on the outer surface and antennae on the inner surface, the protrusion and antennae are made of of the same material as the ring, it is proposed, according to the present utility model, to make the ring from a material based on fluoropolymer, with one radial section.

The utility model is illustrated by an example implementation.

In FIG. 1 shows a radial section of the claimed

seals; in FIG. 2 - the lower part of the seal; in FIG. 3 - section through

A - A in FIG. 2; in FIG. 4 is a view along arrow B in FIG. 3; in FIG. 5 is a view of FIG. 1

The seal contains a housing made of two parts: upper 1 and lower 2. Inside the housing, rings 3 are installed, the number of which can be any. In particular, as discussed in FIG. 1 and 2 of the example, the number of rings 3 is equal to brilliance. Rings 3 are made of a material based on fluoropolymer, for example, fluoroplast -4, etc. and placed in the annular grooves 4, made in the inner surface of the housing (its both the upper part 1 and the lower part 2). On the inner surface of each of the rings 3 there are antennae 5 made, like the rings 3 themselves, of material based

fluoropolymer. The configuration of the shaft, made smooth, with ridges, with mounted bushings determines the reciprocal form of the seal. Each of the rings 3 has a straight radial cut 6, or this cut can be made of various shapes, for example, such as a dovetail, the ends of the rings can be rigidly connected to each other, for example by welding. The ring in the housing to prevent rotation is fixed by means of a lock in the form of a strap 7 made of the same material as the ring itself, located in the recess of the lower part of the housing and the section of the ring.

The material for the ring is selected from among fluorine-containing polymers. Such material, in particular, can be: polytetrafluoroethylene, fluoroplast-4, compositions based on fluoroplast-4 with coke, types F4K 20 and F4K15M5, composition F4GR25, including graphite with a fibrous structure. The difference in technology, heat treatment to ensure the solidity of materials, high structural physical and mechanical properties of the rings.

The seal assembly is carried out in the following sequence:

1 / the ring is bred at the ends in the axial direction to a value exceeding the diameter of the shaft, one of the spaced ends encircle the shaft with a ring;

2 / the ring is installed in the lower part 2, which is fixed; 3 / set the bar 7;

4 / close the strip 7 with the ring connector and deepen the section of the ring into the lower part of the housing;

6 / fasten the case.

When disassembling the seal, remove the upper part of the housing, release the lower part, and then remove the ring from the shaft

The seal is installed on the shaft with a gap determined by the design features of the location.

In the process, the antennae of the ring located on the inner surface, being sharpened, do not wear out the smooth surface of the shaft and its other structural ridges.

In accordance with the claimed decision, a seal was made, which was tested at one of the TPPs of the Sverdlovsk region. Seal test results are positive.

The simplicity of the claimed design solution, its manufacture, high operational applicability and reliability, absolute density in the axial direction, eliminating shaft wear in emergency situations, with ease of assembly and disassembly, without repair and replacement, will provide it with wide practical application in steam and gas turbines, as well as in compressors and other rotating machines. Moreover, the claimed seal can be applied both to newly created turbines and to turbines that are currently in operation during repairs of the latter.

Literature:

L A.V. Scheglyaev. Steam Turbines, M., Energy, 1967

2. S.M. Losev. Steam Turbines, ML, Gosenergoizdat, 1959

Z.N.Ya.Bauman, M.I.Yakovlev, I.N. Svechkov Production technology of steam and gas turbines, M., Mechanical Engineering, 1973.

4. Steam turbine K-500/240 KhTGZ, edited by V.N. Savvina, M., Energoatomizdat, 1984

5.L.I. Tubyansky and L.D. Frenkel High-pressure steam turbines LMZ, ML, Gosenergoizdat, 1956

Claims (1)

A turbine seal comprising a housing in which at least one annular groove is made, in which a ring having a protrusion on the outer surface and an antennae on the outer surface is located, and the protrusion and antennae are made of the same material as a ring, characterized in that the ring is made of a material based on a fluoropolymer and has a radial section.