JP4088367B2 - Shaft end seal device for rotating machinery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seal device for a rotary shaft in a rotary machine such as a steam turbine.
[0002]
[Prior art]
FIG. 3 shows an example of the prior art of a shaft end seal device in a steam turbine.
In FIG. 3, 1 is a casing of a steam turbine, 2 is a rotor (rotating shaft) that is driven to rotate, and 3 and 11 are packing cases fixed to the casing 1. Reference numerals 6 and 7 denote annular packing rings attached to the inner periphery of the packing case 3, and 10 denotes an annular packing ring attached to the inner periphery of the packing case 11. The packing rings 6, 7, 10 are installed with a plurality of labyrinth fins (not shown in detail) provided along the axial direction on the inner periphery thereof in proximity to the outer periphery of the rotor 2.
[0003]
A seal steam pipe 4 is connected to a seal steam inlet space 33 formed between the packing rings 6 and 7, and supplies steam for sealing into the space 33. A space 31 is formed between the packing rings 7 and 10 and is connected to a ground capacitor 5 described later via a discharge pipe 34 and a condenser inlet pipe 35. Reference numeral 5 denotes a ground condenser for preventing the outside air from entering the vehicle interior 32, the inlet side being connected to the space 31 as described above, and the outlet side being connected to the ejector 8 via the outlet pipe 36. 37 is a working air introduction pipe of the ejector 8, and 38 is an ejector discharge pipe.
[0004]
During operation of the steam turbine having such sealing device, the pressure in the cabin interior 32 Pi, the space between the packing ring 7 and 10, i.e. when the pressure in the space 31 at the outlet side and P _2, the packing ring The space between 6 and 7, that is, the seal steam inlet space 33 passes through the seal steam pipe 4 and has a pressure P ₁ higher than the pressure Pi in the vehicle interior portion 32 and the pressure P _{2 in} the space 31 on the outlet side. Steam is being supplied.
The seal vapor seals the vehicle interior portion 32 side by leaking a small amount into the vehicle interior portion 32 through the inner circumferential clearance of the packing ring 6.
[0005]
The pressure P ₂ in the outlet-side space 31 connected to the ground capacitor 5 via the pipes 35 and 34 is sucked by the ejector 8 connected to the ground capacitor 5 and held at a negative pressure. ing.
Therefore, steam and air in the space 31 are discharged from the discharge steam pipe 4 and the inlet pipe 35 to the ground condenser 5 together with the seal steam introduced from the seal steam pipe 4 into the seal steam inlet space 33, and the atmosphere inside the turbine. Intrusion is prevented.
[0006]
Further, the air mixed in the ground condenser 5 is discharged into the atmosphere from the ejector discharge pipe 38 through the outlet pipe 36 and the ejector 8 by the suction action of the ejector 8. Further, the shaft end portion of the steam inlet side shaft end is also sealed by a pipe 9 connected to the seal steam pipe 4 and the ground condenser 5.
[0007]
[Problems to be solved by the invention]
In the prior art shown in FIG. 3, the ground capacitor 5 for adjusting the pressure of the space 31 on the outlet side and discharging the seal vapor and air is required.
For this reason, in this prior art, the ground condenser 5 main body and the ground condenser cooling water equipment attached to the ground condenser 5 are required, the structure of the apparatus is complicated, and the cost is increased. Installation space is required, and the plant space is enlarged.
[0008]
In view of the problems of the prior art, the present invention eliminates the need for a ground capacitor and its attached equipment while sufficiently maintaining the shaft end sealing function, simplifies the apparatus, reduces equipment costs, and further reduces plant space. An object of the present invention is to provide a shaft end seal device for a rotary machine that can be effectively used.
[0009]
[Means for Solving the Problems]
In order to solve such a problem, the present invention provides a first invention in which a first seal fluid such as steam is introduced into a vehicle interior through a seal member provided close to the outer periphery of the rotor. In a rotary machine having a single fluid inlet space, a second fluid inlet space into which a second seal fluid is introduced is provided between the first fluid inlet space and the atmosphere, and the outer periphery of the rotor is radially provided. A disk having a fluid passage extending and having an outlet end positioned on the outer peripheral side of the inlet end is provided, and the inlet end of the fluid passage of the disk communicates with the second fluid inlet space and the outlet of the fluid passage the end communicates with the space formed in the vehicle compartment outside of the disk, large in outer space formed in the vehicle compartment of said disk by boosting the second sealing fluid pumping action due to the rotation of said disk It caused the static pressure on the pressure or the sealing member is discharged to the atmosphere via a discharge pipe by the differential pressure between the static pressure and atmospheric pressure, to seal between the inlet side and the outlet side of the second sealing fluid A sealing device for a rotary machine, comprising:
[0010]
According to a second invention, in the first invention, the disk is formed separately from the rotor, and is fixed to the outer periphery of the rotor by a fixing means such as shrink fitting.
[0011]
According to a third invention, in the first invention, the disk is integrally provided on an outer periphery of the rotor.
[0012]
[0013]
[0014]
According to this invention, the second seal fluid is introduced into the second fluid inlet space formed between the fluid inlet space for sealing and the atmosphere, and the second seal fluid is provided in the radial direction provided on the disk. By flowing in the fluid passage from the inner circumference side to the outer circumference side, the total pressure is increased by the pumping action by the centrifugal force accompanying the rotation of the rotor, and then the dynamic pressure is recovered in the outer space to restore the atmospheric pressure. The above static pressure is generated, and the second seal fluid is discharged to the atmosphere by the difference between the static pressure and the atmospheric pressure, and the inlet side and the outlet side of the second seal fluid are sealed by a seal member. Thus, the shaft end can be reliably sealed without using a ground capacitor as in the prior art.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.
[0016]
FIG. 1 is a cross-sectional view of a main part of a shaft end seal device for a steam turbine according to an embodiment of the present invention, and FIG. 2 is a view taken along line AA in FIG.
1 and 2, reference numeral 1 denotes a steam turbine casing, 2 denotes a rotor (rotating shaft) that is driven to rotate, and 3 and 11 denote packing cases fixed to the casing 1. Reference numerals 6 and 7 denote annular packing rings attached to the inner periphery of the packing case 3, and 10 denotes an annular packing ring attached to the inner periphery of the packing case 11. The packing rings 6, 7, 10 are installed with a plurality of labyrinth fins (not shown in detail) provided along the axial direction on the inner periphery thereof in proximity to the outer periphery of the rotor 2.
[0017]
A seal steam pipe 4 is connected to a seal steam inlet space 33 formed between the packing rings 6 and 7, and supplies steam for sealing into the space 33.
Reference numeral 22 denotes an annular disk fixedly inserted on the outer periphery of the rotor 2 by shrink fitting or the like, and reference numeral 23 denotes a non-rotating screw for stopping the rotation of the disk 22 and the rotor 2. The disk 22 is provided in a space between the inner packing ring 7 and the packing ring 10 on the shaft end side, and a steam passage hole 26 penetrating in the radial direction is formed in the center (FIG. 2). reference).
[0018]
25 is a steam passage groove carved along the mating surface of the disk 22 of the rotor 2, and both end openings communicate with inner and outer spaces 41 and 43 of the disk 22, which will be described later. The portion communicates with the steam passage hole 26 of the disk 22.
[0019]
Reference numerals 16 and 17 denote packing rings installed outside the disk 22 with the open end of the steam passage hole 26 of the disk 22 interposed therebetween. The packing rings 16 and 17 are packing rings having labyrinth fins similar to the packing rings 6, 7, and 10. The packing ring 16 is fixedly supported on the vehicle compartment 1 via a packing case 15, and the packing ring 17 is fixedly supported on the packing case 11 together with the packing ring 10.
[0020]
A space 34 surrounded by the packing rings 16 and 17 is a space on the outlet side where the outer peripheral end of the steam passage hole 26 of the disk 22 opens. Further, an inner space 41, that is, a second fluid inlet space is formed between the packing ring 16 and the packing ring 7, and an outer space 43 is formed between the packing ring 10. 8 is an ejector similar to the prior art, 37 is an air introduction pipe of the ejector 8, 38 is an ejector discharge pipe, and the ejector 8 is used to seal the shaft end when the rotor 2 does not rotate.
[0021]
Reference numeral 19 denotes a pipe serving as a fluid line of steam and air, that is, a second fluid, connected to the second fluid inlet space 41. A pipe 28 is branched from the pipe 19 and connected to the inlet of the ejector 8. Reference numeral 14 denotes a discharge pipe that connects the space 34 and the atmosphere, and steam and air in the exhaust side seal portion that has passed through the steam passage groove 25 and the steam passage hole 26 in the space 34, and steam from the pipe 19. And exhaust air into the atmosphere.
[0022]
In the shaft end sealing device having such a configuration, the seal steam inlet space (first fluid inlet space) 33 passes through the seal steam pipe 4 and is higher than the pressure Pi in the vehicle interior portion 32 and the pressure P ₁ ′ in the space 41. Pressure seal steam (first fluid) is supplied. The seal steam seals the vehicle interior portion 32 side by leaking a small amount into the vehicle interior portion 32 through the inner circumferential clearance of the packing ring 6.
[0023]
Steam and air (second fluid) from the steam inlet side shaft end are guided to the pipe 19, and the steam and air are supplied into the second fluid inlet space 41, and the steam passage groove 25 and the steam passage hole are provided. 26 and flows into the space 34.
[0024]
During the flow of the steam and air, the static pressure P ₁ ′ at the inner peripheral opening ends of the steam passage groove 25 and the steam passage hole 26 at the position of the diameter D ₁ is the rotation of the rotor 2 and the disk 22 fixed thereto. Due to the pumping effect, the total pressure rises while the steam and air move to the outer peripheral outlet end of the steam passage hole 26 having the diameter D _2, that is, the opening end to the space 34.
[0025]
The steam and air having a static pressure P ₂ ′ at the outlet end of the steam passage hole 26 to the space 34 have a static pressure in the space 34 due to the recovery of the dynamic pressure accompanying the increase in the total pressure. It rises to P _B. Then, in order to release the steam and air having the static pressure P _B to the atmosphere through the discharge pipe 14, the pressure is set as in the following formula (1).
[0026]
P _B −P _C = P _E −ΔρgΔH (1)
Here, P _C = atmospheric pressure P _E = pressure loss of piping such as the discharge pipe 14 Δρ = (density of steam and air in the space 34) − (density of air at the outlet of the discharge pipe 14)
ΔH = (exit height of the discharge pipe 14) − (height of the upper end portion of the space 34)
It is.
[0027]
Accordingly, the shape and size of the steam passage groove 25 and the steam passage hole 26 are set so as to obtain the required pressure (static pressure) P _B due to the pumping effect, and the space is set so as to satisfy the equation (1). If the dimensions or points of the pipe 34 and the discharge pipe 14 are set, the steam and air that have entered the space 41 from the steam inlet side shaft end enter the space 34 through the steam passage groove 25 and the steam passage hole 26, and the space 34 Is smoothly discharged into the atmosphere through the discharge pipe 14.
[0028]
Further, by providing the packing rings 16 and 17 between the space 41 and the space 43 communicated with the space 41 via the steam passage groove 25 and the space 34 on the outlet side, respectively, steam and air to the discharge side space can be obtained. Reduce leakage.
[0029]
When the rotor 2 is not rotating, the valve 27 is opened and the ejector 8 is operated to suck the steam and air in the space 41 and the space communicating therewith, thereby sealing the shaft end.
[0030]
The present invention is not limited to the shaft end portion of the steam turbine according to the above embodiment, and can be widely applied to rotating machines that seal the shaft end portion using a sealing fluid, such as a gas turbine, an axial compressor, a pump, and the like. .
[0031]
【The invention's effect】
As described above, according to the present invention, the second seal fluid is guided to the second inlet space formed between the seal fluid inlet space and the atmosphere, and the second seal fluid is provided in the fluid passage provided in the disk. The static pressure in the space outside the fluid passage can be increased to an atmospheric pressure or higher by the pumping effect by flowing the gas in the radial direction, and the second seal fluid is removed from the atmosphere by the differential pressure between the static pressure and the atmospheric pressure. in together when discharged, by sealing the inlet side and the outlet side of the pre-Symbol second sealing fluid seal member, as in the prior art, reliably forms a seal of the shaft end without equipped ground capacitor be able to.
[0032]
Therefore, according to the present invention, the ground capacitor and its attached equipment can be omitted as described above, and the apparatus can be simplified and the apparatus cost can be reduced. Further, the plant space can be effectively utilized by omitting the ground capacitor .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an essential part of a shaft end seal device for a steam turbine according to an embodiment of the present invention.
FIG. 2 is a view taken along line AA in FIG.
FIG. 3 is a diagram corresponding to FIG. 1 showing the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cascade 2 Rotor 3, 11, 15 Packing case 4 Sealing steam pipe 6, 7, 10, 16, 17 Packing ring 8 Ejector 14 Exhaust pipe 19, 28 Piping 22 Disc 25 Steam passage groove 26 Steam passage hole 32 Car interior part 33, 34 Space 37 Air introduction pipe 38 Ejector discharge pipe 41 Space (inside)
43 Space (outside)

Claims (3)

In a rotating machine provided with a first fluid inlet space that is communicated via a seal member provided close to the outer periphery of the rotor in the vehicle interior and into which a first seal fluid such as steam is introduced.
Providing a second fluid inlet space into which a second sealing fluid is introduced between the first fluid inlet space and the atmosphere;
A disk is provided on the outer periphery of the rotor that is provided with a fluid passage that extends in the radial direction and has an outlet end positioned on the outer peripheral side of the inlet end;
Communicating the inlet end of the fluid passage of the disc to the second fluid inlet space and the outlet end of the fluid passage to a space formed in a casing outside the disc ;
The pressure of the second sealing fluid is increased by a pumping action caused by the rotation of the disk to generate a static pressure higher than the atmospheric pressure in a space formed in the casing outside the disk, and the difference between the static pressure and the atmospheric pressure Discharged to the atmosphere through the discharge pipe by pressure,
A seal device for a rotary machine, comprising a seal member for sealing between the inlet side and the outlet side of the second seal fluid.   2. The sealing device for a rotary machine according to claim 1, wherein the disk is formed separately from the rotor and is fixed to the outer periphery of the rotor by a fixing means such as shrink fitting.   The rotary machine sealing device according to claim 1, wherein the disk is integrally provided on an outer periphery of the rotor.

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