JPS58122305A - Variable nozzle mechanism for radial type turbine - Google Patents

Abstract

PURPOSE:To simplify the structure of a suction casing, cause a working fluid to uniformly flow into nozzles and enhance the efficiency of a radial turbine, by extending the driving shaft of a variable nozzle mechanism for the radial turbine toward its discharge side so that the shaft penetrates the casing. CONSTITUTION:Shafts 13 are attached to blade-shaped members 4 provided at nozzles 12 in a turbine casing 9 and are interlocked with one another by a linkage 14. One of the shafts 13 is a long driving shaft 13a which extends toward the discharge side of a turbine through the flange of a discharge casing 9c and is turned through an arm 16. The driving shaft 13a does not hinder the flow of a working fluid in a suction casing 9a. Since the connection of the driving shaft 13a and the arm 16 and the vicinity thereof are enclosed with a cover 26 and an antifreezing solution is filled therein, operation is prevented from becoming impossible due to clinging water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable nozzle mechanism for a radial steam turbine equipped with a variable nozzle mechanism for controlling exhaust pressure, and is particularly suitable for application to a radial steam turbine that uses steam as a working fluid. It is.

The variable nozzle mechanism in a conventional radial turbine is generally a slide ring type as shown in FIG.

Its structure is such that an airfoil member 4 is provided between a fixed ring 2 and a slide ring 3 that can rotate.
A hole 7 into which a pinning pin 5 attached to the fixing ring 2 is inserted and an elongated hole 8 into which a pin 6 attached to the slide ring 3 is slidably inserted are provided on the end face of the ring. An operating rod 1 connected to an external operating device is attached to the slide ring 3, and by moving the operating rod 1 up and down,
The slide ring 3 is rotated, and as the slide ring 3 rotates, the bin 6 slides within the elongated hole 8 of the airfoil member 4, and at this time, the airfoil member 4 rotates around the fixed bin 5. Nozzle opening degree can be changed.

Next, the relationship between the operating rod 1 and the suction casing in the slide ring system described above will be explained with reference to FIG. 2.

As shown in this figure, in the conventional variable nozzle mechanism (slide ring method), the operating rod 1 is connected to the suction casing 9a.
It has a structure that penetrates the steam flow path inside. In this way, in the conventional one, the operating rod 1 penetrates the steam flow path immediately in front of the nozzle part 12, so that the nozzle part 1
Compared to No. 2, this had the disadvantage that it prevented the steam from flowing in uniformly.

In order to prevent the operating rod 1 from penetrating the steam flow path, it is also possible to replace the positions of the slide ring 3 and fixed ring 2 shown in FIG. 2 and take out the operating rod 1 from the gear device 10 side. However, this has the following two problems. First, in order for the rotational movement of the slide ring 3 to be performed without uneven contact, the operating rod 1 must
It is necessary that the i-continuation point to the slide ring 3 be located near the center of the slide ring 3 in the width direction. Therefore, the operating rod 1 passes through the wall of the suction casing 9a. Since the operating rod 1 moves up and down while swinging laterally, a large hole is drilled in the suction casing 9a in consideration of the range of movement of the operating rod 1, and a seal for steam (working fluid) is required. Considering also,
The structure of the suction casing 9a becomes very complicated.

In addition, since the strength of the suction casing 9a is reduced due to the hole for penetrating the operating rod 1, the strength of the suction casing 9a is reduced accordingly.
1 has to be made larger, but the gear device 10
A certain amount of space is required between the casing 15 that covers the suction casing 9a and the suction casing 9a for maintenance reasons.For this reason, when the thickness of the suction casing 9a is increased, the axial length of the overhanging turbine shaft 11 is must also be made longer. Therefore, the critical speed of the turbine shaft 11 decreases, resulting in an unfavorable condition for turbine operation. In this way, in the conventional system, even if a structure is adopted in which the operating rod 1 does not penetrate inside the steam flow path, the structure of the suction casing 9a becomes complicated or the critical speed is reduced (critical speed and There was a drawback that the difference in operating speeds became small.

The present invention has been made based on the above-mentioned matters, and it is possible to uniformly flow the working fluid into the nozzle section for adjusting exhaust pressure, and to avoid complicating the structure of the suction casing and reducing the critical speed of the turbine shaft. The purpose of this is to obtain a variable nozzle mechanism for a radial turbine that does not reduce the exhaust pressure.In a radial turbine equipped with a variable nozzle mechanism that controls exhaust pressure, the shaft and connecting the respective shafts so as to interlock with each other by a link mechanism, at least one of the shafts being a drive shaft, and extending the drive shaft in the direction of the discharge side of the turbine to penetrate the casing, The purpose is to allow the drive shaft to rotate.

That is, in the present invention, the drive shaft of the airfoil member is extended in the direction of the discharge side so that the member operating the airfoil member does not penetrate into the flow path of the suction casing. Therefore, the working fluid uniformly flows into the exhaust pressure adjusting nozzle portion, thereby improving the efficiency of the radial turbine.

Further, since the drive shaft of the maple-shaped member does not penetrate the suction casing, there is an effect that the structure of the suction casing is not complicated and the critical speed of the turbine shaft is not reduced.

An embodiment of the present invention will be described below with reference to FIGS. 3 to 6. In the figures, parts given the same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts.

In FIG. 3, 9 is a cage/g of the turbine section, and 9a
9b is a suction casing, 9b is an intermediate casing, and 9C is a discharge casing. Reference numeral 13 denotes a shaft attached to each airfoil member 4 provided in the nozzle portion 12, and each shaft 13 is connected by a link mechanism 14 so as to interlock with each other.

The airfoil member 4 and the shaft 13 are integrated by welding or the like, and one of the shafts x% is used as a driving shaft 13a having a long shaft length, and the other shaft is used as a driven shaft 13b.

The drive shaft 13a extends in the direction of the discharge side of the turbine, passes through the flange portion of the discharge casing 9C, and the shaft end is connected to the arm 16 by an operating rod 17 that is operated from the outside.
are connected via. Therefore, the operating rod 17
By operating the nucleus movement axis 1 via the arm 16
331 can be rotated. The drive shaft 13g is supported by an oil-free bush bearing 18 built into the intermediate casing 9b and a roller bearing 19 provided at the 7 flange portion of the discharge casing 9C.
The driven shaft 13b is an oil-free type bush bearing 18.
Supported only by As mentioned above, each shaft 13 is connected by a horizontal link 14, the details of which will be explained with reference to FIG. 4. A rotatable guide ring 20 is provided on the inner peripheral side of each shaft 13, and an arm 22 is attached to each shaft 13, and this arm 22 and the guide link 20 are connected like a turnbuckle. Connecting member 2
1. The connecting member 21 includes a connecting rod 21a having a left-hand thread at its end and rotatably attached to the guide link 20, and an arm 22 having a right-hand thread at its end.
The connecting rod 21b is rotatably attached to the connecting rod 21B, and a special nut 21C having a left-hand threaded portion and a right-handed threaded portion is used to connect the connecting rods 21M and 21b. With this configuration, when the drive shaft 13m is rotated by the operating rod 17 provided externally, the guide ring 20 is rotated by the nine arms 22 and the connecting member attached to the drive shaft 13M, and the kite ring rotates 200 times. Each connecting member 21 and arm 22
Each driven shaft 13b can be rotated via. Therefore, by operating the operating rod 17, the mounting angles of all the airfoil members 4 attached to each shaft 13 can be changed simultaneously, and thereby the opening degree of the nozzle portion 12 can be changed.

Figure 5 is an enlarged view of the part where the drive shaft 13a penetrates the discharge casing 9C and protrudes to the outside, and this part is shown in the electric diagram because it becomes considerably cold due to the expanded steam (working fluid). As such, the water vapor contained in the surrounding air freezes, and an ice layer 23 comes to cover the discharge casing 9C. If the ice layer 23 adheres to the drive shaft 13a, the rotational movement of the drive shaft 13a will be hindered, and it is also expected that the opening degree of the nozzle portion 12 may become impossible to adjust. Therefore, in this embodiment, as shown in FIG. 3 and FIG.
5 is provided at a portion of the drive shaft 13Fl that passes through the discharge casing 9C. This antifreeze means 25 protects the parts of the drive shaft 13a and arm 16 that are considered to be covered with ice 123, that is, the part of the drive shaft 13a that protrudes outside through the discharge casing 9C, and the drive shaft 13a of the arm 16. A cover 258 is attached to the discharge casing 9C so as to cover the vicinity of the connecting portion, and the cover 25a is filled with a liquid 25b such as hydraulic oil having a low freezing temperature. With this configuration, arm 1
6 and the drive shaft 13a, the liquid 25b does not freeze and maintains fluidity even in a low temperature state, so that the rotation of the drive shaft 13a can always be performed smoothly.

The effects of the embodiments described above are summarized as follows.

l) Since the drive shaft 13a of the airfoil member 4 is extended in the discharge side direction, the member that operates the airfoil member 4 is connected to the suction casing 9a.
Since the working fluid can be prevented from penetrating the inside of the flow path, and therefore the working fluid can uniformly flow into the exhaust pressure adjusting nozzle section, the efficiency of the radial turbine can be improved.

2) The drive shaft 13a of the airfoil member 4 is connected to the suction casing 9-a
, the structure of the suction casing 9a is not complicated and the critical speed of the turbine shaft 11 is not reduced.

3) Since the antifreeze means 25 is provided, the drive shaft 13a
Rotational movement can always be performed smoothly.

4) In the conventional slide ring method, the airfoil member 4 needs to be long enough for the pin to slide.
Whereas only thick airfoil members could be used, in this invention, the shaft 13 is attached to the airfoil member 4, so it is now possible to use thin airfoil members as well. Therefore, in the present invention, the nozzle portion 12
This has the effect that the shape can be freely selected.

5) Since each shaft 13 and the guide lifter 20 are connected by a connecting member 21 such as a turnbuckle, the opening degree of the nozzle portion 12 can be easily adjusted even after the variable nozzle mechanism is assembled. There is an effect.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing a variable nozzle mechanism in a conventional radial turbine. Figure 1 is a partially cutaway perspective view showing only the main parts, and Figure 2 is a variable nozzle mechanism shown in Figure 1. 31 to 6 are views for explaining one embodiment of the present invention, FIG. 3 is a longitudinal sectional view thereof, and FIG. A side view to clarify in detail the part of the link mechanism shown in the figure, and Figure 5 is an enlarged cross-sectional view showing the part where the drive shaft penetrates the discharge casing and discharges to the outside, without anti-freezing means. FIG. 6 is a sectional view showing the same part as FIG. 5, and is a diagram showing the case where anti-freezing means is provided. 4... Airfoil member, 9... Casing, 9C... Discharge casing, 12... Nozzle portion, 13... Shaft, 1
3a... Drive shaft, 14... Link mechanism, 25...
Freeze prevention means, 25J! ...Cover, 25b...Liquid (hydraulic oil). Agent Patent Attorney Toshiyuki Usuda - 1st day η 2nd) F13 Figure 18 ′yfI4 (2)

Claims (1)

[Claims] 1. In a radial turbine equipped with a variable nozzle mechanism for controlling exhaust pressure, a shaft is attached to each airfoil member provided in the nozzle part, and each shaft is interlocked with each other by a link mechanism. At least one of the shafts is used as a drive shaft, and the drive shaft is extended in a direction toward the discharge side of the turbine to penetrate the casing and rotate the drive shaft. Variable nozzle mechanism for radial turbines. 2. The radial turbine according to claim 1, characterized in that the radial turbine according to claim 1 is provided with anti-freeze means for preventing the portion of the drive shaft that protrudes outside through the discharge side casing from freezing. Variable nozzle mechanism. & A cover is attached to the casing so as to cover the portion of the drive shaft that penetrates the casing and protrudes to the outside, and the cover is filled with a liquid having a low freezing temperature, thereby configuring the antifreeze means. A variable nozzle mechanism in a radial turbine according to claim 2. t. The variable nozzle mechanism in a radial turbine according to claim 3, characterized in that hydraulic oil is used as the liquid with a low freezing temperature.