JPS6147287B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a double flow diaphragm structure in a steam turbine that prevents the diaphragm from floating when an upper casing is removed.

[Background of the invention]

FIG. 1 shows the structure around a double-flow diaphragm that has been commonly used in conventional low-pressure steam turbines. In the figure, O-O indicates the central axis position,
The figure shows a state in which the low-pressure turbine is cut in the axial direction. The working steam 7 introduced into the steam turbine passes through the nozzle blades 4, performs work with the blades 5, and flows to the next stage. Double flow type diaphragm 1
is arranged concentrically with the axle 3, and engages with the axle 3 via a packing 14, as shown in FIG. Further, a convex portion is formed on the outer circumference of the double flow type diaphragm 1, and is loosely inserted into a diaphragm insertion groove formed on the inner surface side of the compartment 2. In addition, vehicle compartment 2
The insertion portions of the double flow type diaphragm 1 and the double flow type diaphragm 1 are in contact with each other at a joint surface 6 as shown in FIG. Figure 2 shows
This is a cross section taken along line AA in FIG. 1. As clearly shown in the figure, the axle 3, the casing 2, and the nozzle blade 4
and the double flow type diaphragm 1 are all arranged concentrically. The double flow type diaphragm 1 is divided into two parts along its diametrical cross section into an upper half diaphragm 1a and a lower half diaphragm 1b, which are screwed together by upper and lower tightening bolts 9. Lower half diaphragm 1b
A diaphragm fixing device 11 is installed near the diametrical end of the joint with the upper half diaphragm 1a. As shown in detail in FIG. 3, this diaphragm fixing device 11 is disposed across both a support bar groove 11h formed in the lower half casing 2b and a support bar groove 11g formed in the lower half diaphragm 1b. A support bar 11a is provided, a bolt 11d is fixed to the lower half diaphragm 1b using the groove 11g, a shim 11b is fixed to the bottom of the groove 11h with a bolt 11e, and a bolt is attached to the upper end of the support bar 11a. It consists of a liner 11c fixed with a liner 11f.

The support bar 11a is connected to the lower half diaphragm 1b.
When the diaphragm 1b is assembled into the lower half casing 2b, its lower end engages with the upper end of the shim 11b to position the lower diaphragm 1b and to support the rotational reaction force generated on the diaphragm during turbine operation. be.

Further, the position of the lower half diaphragm 1b in the circumferential direction is adjusted by the center pin 12.

The liner 11c adjusts the gap between the upper half casing 2a and the lower half diaphragm 1b. Also,
The shim 11b is for adjusting the height of the lower half diaphragm 1b.

On the other hand, when the steam turbine is disassembled, the upper half casing 2a is lifted up. At this time, the upper half of the cabin 2a is lifted while maintaining its horizontal state, but due to the heavy cabin weight of several tens of tons and the deformation of the cabin due to lifting, the cabin tilts slightly from front to back and from side to side. It will be hoisted up. Therefore, as shown in FIG. 4, the joint surface 6 between the casing 2 and the double-flow diaphragm 1 is pressed in the direction of the arrow. Therefore, a force is applied to the double flow type diaphragm 1 that tends to lift it together with the compartment 2. Further, the joint surface 6 is likely to be seized by steam during turbine operation.
This seizure increases the frictional force of the joint surface 6, and the force that tends to lift the double flow type diaphragm 1 increases. Upper half diaphragm 1a and lower half diaphragm 1
The joint surface with b is screwed with the upper and lower tightening bolts 9 as described above in order to minimize the leakage of steam from this joint surface and increase the efficiency of the turbine. Therefore, when lifting the upper half compartment 2a,
The force that lifts up the upper half diaphragm 1a is applied to the lower half diaphragm 1b via the upper and lower tightening bolts 9, causing the lower half diaphragm 1b, which should not normally be lifted, to float. On the other hand, as shown in FIG. 7, a packing ring 14 is inserted into the inner diameter portion of the diaphragm 1. This packing ring 14 is arranged in a ring shape with respect to the axle 3, and the comb teeth of the packing ring 14 and the axle 3 are assembled so as to maintain a gap of usually 2 mm or less to prevent steam leakage. Therefore, as described above, when the lower half diaphragm 1b floats up due to lifting of the vehicle compartment 2, the comb teeth of the diaphragm gasket 14 collide with the axle 3, damaging the diaphragm gasket 14, which may lead to an accident. will occur.

[Purpose of the invention]

The present invention was proposed to solve the above-mentioned drawbacks, and its purpose is to:
To provide a double flow type diaphragm structure capable of preventing damage caused by interference between an axle and a packing ring without causing the diaphragm to float even when a vehicle compartment is lifted.

[Summary of the invention]

In order to achieve the above object, the present invention has a method in which a bolt is screwed into the lower half of the diaphragm fixing device, and the tip of the bolt engages with the bottom surface of a support bar groove formed in the lower half of the diaphragm. This restricts the floating of the lower half diaphragm.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. In FIG. 5, as in the case of the conventional example, the outer peripheral convex portion of the lower half diaphragm 1b is connected to the lower half casing 2b.
The diaphragm insertion groove 1c is inserted into the inner surface of the diaphragm insertion groove 1c, and the two are engaged with each other by a support bar 11a.
A support bar groove 11h is formed in the lower half chamber 2b near the diametric end of the joint surface between the lower half diaphragm 1b and the upper half diaphragm 1a. Lower compartment 2b
A stopper bolt 16a is inserted through the diaphragm insertion groove 1c side from the steam flow path side. The stopper bolt 16a is fixed to the lower compartment 2b by a washer 16b. Figure 6 shows the fifth
The stopper bolt 1 is shown in the EE cross section of the figure.
6a and the lower half diaphragm 1b are displayed in detail. The size of the stopper bolt 16a is such that the size of the stopper bolt 16a is such that the diaphragm 1a is
It shall have sufficient shear strength against a force greater than the frictional force acting on the joint surface 6 between the upper half compartment 2a and the upper half casing 2a. The insertion side outer peripheral surface of the stopper bolt 16a is installed so as to have a minute gap 17 with the bottom surface of the support bar groove 11g of the lower half diaphragm 1b. This gap 17 is set smaller than, for example, a packing ring gap 15 between the comb teeth of the packing 14 inserted into the inner groove of the diaphragm 1 and the outer periphery of the axle 3, as shown in FIG.

In the diaphragm structure as described above, when lifting the upper half casing 2a during turbine disassembly, the upper half diaphragm 1a and the lower half diaphragm 1b are integrated by tightening bolts 9. When the upper casing 2a is lifted, a large frictional force is generated at the fitting portion between the upper casing 2a and the upper diaphragm 1a, and this force causes the lower diaphragm 1b to float upward through the tightening bolts 9. It will act as a force to

However, when the bottom surface of the support bar groove 11g of the lower half diaphragm 1b comes into contact with the outer periphery of the stopper bolt 16a, the force that lifts the lower half diaphragm is transmitted to the lower half compartment 2b via the stopper bolt 16a. lower half diaphragm 1b
does not rise any further, and therefore the axle 3 and packing 14 do not come into contact with each other.

When the upper half compartment 2a is removed, the tightening bolt 9 is removed, the upper half diaphragm 1a is disassembled, the axle 3 is removed, and the stopper bolt 16a is removed, the lower half diaphragm 1b is removed from the lower half compartment 2b. Can be disassembled.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when the turbine is disassembled, the diaphragm can be prevented from floating together with the casing, and the packing ring inserted between the axle and the diaphragm can be completely prevented from being damaged. It is possible to increase the effectiveness of prevention.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the area around a conventional double-flow diaphragm, Figure 2 is a cross-sectional view taken along line A-A in Figure 1, Figure 3 is a cross-sectional view taken along line B-B in Figure 2, and Figure 4 is a cross-sectional view taken along line B-B in Figure 2. FIG. 1 is a detailed sectional view of section C in FIG. 1, FIG. 5 is a plan view showing the configuration around a diaphragm showing an embodiment of the present invention, FIG. 6 is a sectional view taken along line E--E in FIG. 5, and FIG. F in Figure 1
- Detailed sectional view of section F. DESCRIPTION OF SYMBOLS 1...double flow type diaphragm, 1a...upper half diaphragm, 1b...lower half diaphragm, 2...compartment, 2a...upper half compartment, 2b...lower half compartment, 3...
...Axle, 6...Joint surface, 11a...Support bar, 11h, 11g...Support bar groove, 14...
... Packing ring, 15... Packing ring gap, 16a... Stopper bolt, 16b...
Watsusha, 17...Gap.

Claims (1)

[Scope of Claims] 1. Has a cylindrical inner surface concentric with the axle of the steam turbine, has a diaphragm insertion groove formed on the inner surface, and is divided into an upper half casing and a lower half casing by its diameter cross section. a casing, an upper half diaphragm and a lower half diaphragm that are loosely inserted into the diaphragm insertion grooves of the upper half casing and the lower half casing, respectively, and each have a packing ring at their inner peripheral end; and the upper half diaphragm and the lower half diaphragm. and a support bar groove formed in both diameter ends of the lower half diaphragm near the joint surface of the upper half diaphragm, and a support formed in the lower half casing opposite to the groove. In a double flow type diaphragm having a support bar which is arranged astride both the bar groove and the support bar which is fixed to the lower half diaphragm, it is screwed into a part of the lower half casing from the steam flow path side of the lower half casing. A stopper bolt is provided, the tip of which extends into the support bar groove of the lower half diaphragm, and the stopper bolt and the bottom surface of the support bar groove of the lower half diaphragm are opposed to each other through a small gap, so that the lower half diaphragm is A double flow type diaphragm structure characterized in that floating is prevented by the stopper bolt. 2. The minute gap described in claim 1 is
A double-flow diaphragm structure characterized in that the radial gap between the packing ring and the turbine axle is smaller than the minimum gap between the packing ring and the turbine axle.