JPS5925842B2 - Collar to replace disk removed from turbine shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to segmented collars, and more particularly to collars that replace disks in turbine rotors.

Large, low-pressure steam turbine rotors are formed by shrink-fitting disks onto stepped shafts.

When shrinkage is lost due to excessive speed increase or thermal transients, axial movement of the shrinkage-fastened disks can be limited by assembling the disks with a small axial gap between the disks. has been done.

When damage sustained by a disk necessitates its removal, it is desirable to mechanically remove the damaged disk in order to restore operation to the rotor.

In such cases, it may be necessary to insert a collar or spacer into the space after the damaged disk has been removed to prevent excessive axial movement of the adjacent disk and to prevent further damage to the turbine. be.

A collar replacing a disk removed from a turbine shaft, according to the invention, comprises a pair of arcuate, substantially semicircular first divisions having an axial dimension substantially equal to the axial dimension of the removed disk. a pair of arcuate and substantially semicircular second segment rings arranged to cover the first segment ring and a joint portion of the first segment ring; and first and second segment rings. and a plurality of radial bolts extending between the first and second split rings for connection into a continuous collar.

The joint of the split ring is provided with at least one groove in which a key is inserted and retained to prevent rotation of the collar with respect to the turbine axis.

The objects and advantages of the present invention will become more apparent from the following examples in conjunction with the accompanying drawings.

Referring to the drawings, FIG. 1 shows a portion of a low-pressure steam turbine having a rotor 3 consisting of a stepped shaft 5 on which a plurality of disks 7 are compressed and fastened. has been done.

One of the intermediate discs has already been removed by machining or other means.

Since the outer rotor 7 is shrink-fitted onto the shaft 5, it is impossible to remove them in the field, and during operation, due to excessive speed-up or thermal transients, the outer rotor 7 is inside the removed disc. The shrinkage fastening discs are released from their shrinkage fit and are allowed to slide axially due to the pressure difference between the rotary vanes 9 arranged on the discs 7.

Therefore, in order to prevent excessive axial movement of the inner disk 7 without removing the outer disk 7, a split collar 11 is placed on the shaft in place of the removed disk.

As shown in Figures 2-4, the divided collar 1
1 is formed from a pair of first split rings 13 and likewise a pair of second split rings 15 having an axial dimension substantially equal to the thickness of the removed disc.

All rings 13 and 15 are formed from flat bars that run in a gentle semicircular path and have a plurality of alignment holes 17 and 19 for receiving shoulder bolts 21.

The holes 17 in the inner first split ring 13 are threaded and counterbored to receive the stepped bolts 21, while the holes 19 in the outer second split ring 15 are dimensioned with approximately constant diameter. , and the stepped portion 2 of the stepped bolt 21
3 is aligned with the counterbore of the hole 17 into which the receiver is inserted.

Holes 17 and 19 are spaced apart to form two circumferential rows.

The joint of the inner split ring is approximately 90° from the joint of the outer split ring, which allows the split ring to be placed in position on the axis without additional removal of the disc.

A key 25 is also arranged between the collar 11 and the spacer ring 27 to provide a device for preventing rotation of the collar 11 with respect to the axis 5.

Grooves 31 and 33 are formed at the junction of each split ring forming the outer ring and are aligned with grooves 35 in the spacer ring 27 to capture the key 25 and allow it to pop out of the keyway as the rotor rotates. can be prevented.

Inner shroud extensions 37 are arranged to close the openings left between the fixed vanes 39 when the disc and its attached rotating vanes 9 are removed from the shaft.

As previously mentioned, the collar 11 allows for installation of the collar without additional disk removal, allows easy removal of the collar 11 for future inspection of adjacent disks, and prevents shaft welding, machining, Alternatively, since no drilling is required, the original shape of the shaft 5 is not damaged, and furthermore, when the turbine is removed from the operating line for a long time in the future, another disk 7 can be shrink-fastened onto the shaft 5. 18,

[Brief explanation of the drawing]

Figure 1 is a partial sectional view of a steam turbine equipped with a collar, Figure 2 is a partial sectional view taken along line ■-■ in Figure 1, and Figure 3 is a partial sectional view taken along line ■-■ in Figure 2. FIG. 4 is a partial cross-sectional view taken along line -IV in FIG. 3... Rotor, 5... Turbine shaft, 7... Disk, 9... Rotating blade, 11... Collar, 13...
First divided ring, 15...Second divided ring, 17.1
9... Hole, 21... Stepped bolt, 23... Step, 25... Key, 27... Spacer ring, 31,
33, 35...groove.

Claims (1)

[Claims] 1. A collar replacing a disk removed from a turbine shaft, said collar having an axial dimension equal to the axial dimension of the removed disk and having an arcuate and substantially semicircular pair. a first split ring, and a pair of arcuate and substantially semicircular second rings arranged to cover the first split ring and the joint portion of the first split ring.
In order to connect the split ring and the first and second split rings to form a continuous collar: between the first split ring and the second split ring, a large number of 11 radial boats are connected. a collar which stops and is provided with at least one groove in the joint of the splitting ring, into which a key is inserted and locked in order to prevent rotation of said collar with respect to the turbine shaft;