CZ20002759A3 - Axial coupling for turbine rotor torque transmission - Google Patents

Abstract

An axial connection (44) transmitting torque between the pair the adjacent impellers (38, 40) is comprised of a first an impeller (38) having a first set of axially extending the joints (48), wherein the first set of joints (48) is distributed circumferentially in an annular array around the first face with the first slots (54) between them and further from the second impeller (40) having a second set of axially extending joints (52), wherein the second set of joints (52) extends circumferentially in an annular array with second slits (50) therebetween. First the set of joints (48) is inserted into the second slots (50) and the second the set of joints (52) is inserted into the first slots (54). Everybody from of the first set of joints (48) engages with an adjacent joint (52) of the second set only on a single radial surface (66).

Description

Technical field

The present invention relates to an axial connection transmitting torque.

BACKGROUND OF THE INVENTION

Some gas turbines and compressor rotors were historically “stackable constructions, where a set of individual wheels and shafts were held together by a set of bolts directed axially through the stack. The tension in the bolts here compresses the wheels and shafts and holds them together, and the frictional forces then allow torque transmission across the interface without relying on the shear strength of the bolts. Significant changes in the friction coefficients of flange faces, bolt assemblies, and machine operation can lead to significant changes in rotor torque transfer capability. Continued operation at elevated temperatures may result in loosening the bolt tension and further reduce rotor torque transfer capacity.

The friction-driven torque capacity of driven machines is now approaching, due to higher operating temperatures associated with newer and higher compression ratios and high ignition temperatures of these machines. Furthermore, operation with low-heat synthetic fuels ("process fuels") increases the permissible power of the machines without simultaneously altering the rotor design. If the torque requirements of the rotor exceed its true capabilities, the wheels will slip relative to each other, usually resulting in a spiral or "eccentric rotor". The imbalance that results from this will cause the machine to shut down due to unacceptable vibration and will require time-consuming machine disassembly and reassembly.

Many different approaches to torque transmission, including friction, bolt shear strength, bolt radial gearing, bolt impeller gearing, etc., have been applied in industrial gas turbines or other rotary machines, but. they all had disadvantages in their own way.

The essence of the inventions

The present invention provides a system for positive torque transmission between rotor stages (both turbine and compressor stages), designed to improve the torque transmission capabilities of industrial gas turbines and to reduce the variability of these capabilities. The introduction of such a system often also reduces the need for higher pressure loads in the rotor set, thereby allowing a reduction in bolt stress and / or bolt diameter. This will increase the design span of the screws and reduce the rotor dead loads and mains load, or reduce weight.

An example of the present invention is one that consists of a set of axially extending "joints" machined in adjacent wheels to be joined. These joints

they join together across the flange face. The joints themselves have no radial or axial interface and are therefore used here in accordance with a rebate joint which maintains the radial alignment of the rotor. Axial bolts are still required to hold the whole structure together, but because the joints carry peripheral loads (torque), high compressive loads are not necessary and the bolt stresses or diameters can be reduced relative to the values currently used.

Accordingly, in a broader context, the present invention relates to an axial torque transmission connection between a pair of adjacent rotating machine impellers comprising a first impeller having a first set of axially extending joints, the first set of joints extending circumferentially in an annular field around the first face with the first slots between each other, and further from a second impeller having a second set of axially extending hinges, the second set of hinges extends circumferentially in an annular array with the second slots between each other, the essence being that the first set of hinges is inserted into the second slots and the second set of hinges are inserted into the first slots, each of the first set of hinges engaging the adjacent hinge of the second set, and only on a single radial surface.

List of figures in drawings

This The invention is further described with reference to examples pictures on the attached drawings, on which: Giant. 1 shows partial rust conventional axial compressor and gas turbine, Giant. 2 shows a partial cut in side view, led through torque transmission between rotor parts in

in accordance with the invention,

Giant. 3 shows a partial sectional view of the drive train shown in FIG. 2; and

Giant. 4 is a partial perspective view of the drive illustrated in FIG. 2 and FIG.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows in general the environment of the present invention. Specifically, the figure shows an axial compressor 10 and a gas turbine 12. Air from the compressor 10 is discharged into a ring of conventional combustion chambers 14 spaced circumferentially around the rotor 16. Only the final five degrees at the rear end of the compressor are shown and indicated generally by position 18 An axially elongated tightening bolt 20 is shown in part and several such bolts are spaced circumferentially around the rotor and keep the compressor stages 18 or impellers together.

Similarly, the stages or impellers 22, 24, 26 and 28 of the gas turbine are interspersed by spacers 30, 32 and 34 and held together by a similar array of clamping screws (not visible), one of which has an axis 36.

Giant. 2 and 3 show joint properties in accordance with the present invention. Specifically, the two adjacent impellers 38 and 40 engage with each other at an interface along a surface 42 extending in the radial direction between the radially outer torque transmission coupling 44 and the radially inner axially centered rebate coupler 46 6. The radially outer torque transmission coupling 44 rotates consists of a circumferentially spaced array of intermeshing teeth or joints, wherein the joints 48 formed in the impeller 38 are inserted into the slots 50 between

between the joints 62 of the last adjacent joints 52 on the impeller 40. Similarly, the joints 52 formed in the wheel 40 are slid into the slots 54 between the adjacent joints 48 on the impeller. Since the joints 48 and 52 and the slots 50 and 54 are identical, only the impeller 38 will be described in more detail.

Referring also to FIG. 4, the joints 48 extend axially from the impeller 38 in the annular field. The radially inner surface 56 (below the hinge 48) projects axially beyond the radially outer surface 58 (above the hinges 48) to form axial slats or flanges 60 circumferentially aligned with the radially inner surface of said. However, the joints 52 on the wheel 40 will not be seated on the surface 60. In fact, the joints 48 and 52 have no radial or axial interference and engage only along opposite surfaces 64 and 66 (see also FIG. 3) in the direction of rotation of the rotor. 70 on the opposite side of the joints slightly offset from each other. In other words, the axial length of the slots 50 and 54 is greater than the axial length of the joints 48 and 52 to prevent axial interference. Similarly, the slots 50 and 54 are undercut slightly deeper radially than the radial inner surfaces of the joints 48 and 52 to prevent radial interference between the impellers. The rebate coupling shown in point 4 6 will provide a radial overhang / centering function and ensure that all impellers are on the center axis of the rotor.

The sides of the slots 50 and 54 and the joints 48 and 52 are machined radially in the impeller so that they can secure the wheels. This adjacent impeller can occur due to mechanical or thermal load. Since this property is not used for radial alignment of the rotor, the wear resulting from the relative motion of the differential motion slipping toward each other and adjacent the orbits of this relative motion is not used for radial rotor alignment, the wear resulting from this relative motion should be minimal (and less that arises on conventional types of connections).

The number of slots / joints must be an integral multiple of the number of holes 72 of the clamping screws (for the clamping screws shown in FIG. 2 by the dashed line at position 7 3). This will allow the rotor to be assembled with any orientation (clockwise or counterclockwise) as needed to balance the rotor. The actual number can be determined to provide adequate shear strength so that they can transmit the desired rotor torque. Note also that the circumferential orientation of the joints / slots must be controlled relative to the orientation of the holes 72 of the clamping screws.

Because the slots 50 and 54 are machined slightly wider than the joints 48 and 52 to avoid circumferential displacement of the impellers during the initial start of the machine, the assembly procedure should include the circumferential positioning of the impellers, and the rotation of each wheel in the direction an operationally applied torque as applied to the impellers. In this way, the only dimension of the slots and joints that need to be firmly controlled is the orientation of the loaded faces relative to the position of the bolt hole (slot depth, height and width are much less critical to steering). It is contemplated that for an impeller with a diameter of five feet, the joints may have an axial length from 1/2 (12.7 mm) to 1 inch (25.4 mm) and a circumferential width of about 3 inches (76.2 mm). These dimensions may vary, however, depending on the specific application.

The invention can be applied at any interface between adjacent impellers, both in compressors and in turbines. On the one hand, the interface at the rear end

The compressor and the front end of the turbine may benefit particularly from a torque transmitting drive device in an embodiment of the present invention. For example, in one of the preferred embodiments of the present invention, the rear 5 stages of the 18-stage compressor and at least the stages 2 and 3 of the turbine may incorporate the invention. In addition, the joint where the compressor is connected to the turbine may be similarly equipped.

While the invention has been described in connection with what is currently considered to be the most practical and preferred embodiment, it is clear that the invention is not limited to this clarified embodiment but, on the contrary, is intended to cover various modifications and equivalent arrangements included in the invention. within the scope of the appended claims.

Claims (12)

PATENT CLAIMS An axial connection (44) transmitting torque between a pair of adjacent impellers (38, 40), comprising a first impeller (38) having a first set of axially extending joints (48), the first set of joints (48) being distributed. circumferentially in the annular array around the first face with the first slots (54) therebetween, and further from a second impeller (40) having a second set of axially elongated joints (52), the second set of hinges extends circumferentially in the annular array with the second slots ( 50) between each other, characterized in that the first set of hinges (48) is inserted into the second slots (50) and the second set of hinges (52) is inserted into the first slots (54), each of the first set of hinges (48) engaging the an adjoining joint (52) of the second set and only on a single radial surface (66). The torque transmitting axial connection (44) of claim 1, wherein the first impeller and the second impeller have radially inner and outer surfaces (56, 58), said radial surface (62) protruding axially outside said radially an outer surface (58). The torque transmitting axial connection (44) of claim 2, wherein said axial surface (60) separating the radially inner and radially outer surfaces (56, 58) is flush with the inner surface (62) of each hinge (62). 48) and thus forms the bottom of said slots (54). The torque transmitting axial connection (44) of claim 1, further comprising a rebate coupling (46) between said first impeller and the second impeller. 5. The axial connection (44) transmitting the torque * • • • ·· • • ♦ ··· • · • 9 • • • 9 • · E E • · • • • 9 • · ·· · • · • 9 · according to claim and., characterized s e that first orbiting bike and the second impeller (40, 40) forms the first and second degree (22, (24) gas turbines (12). The torque transmitting axial connection (44) according to claim. 4. characterized in that the first and second sets of joints (48, 52) are spaced radially outwardly from said rebate connection (46). The torque transmitting axial connection (44) of claim 6, further comprising a plurality of tightening screws (73) extending axially between at least said first and second impellers (38, 40). The torque transmitting axial connection (44) of claim 7, wherein said plurality of tightening screws (73) is disposed radially between said first and second sets of hinges (48, 52) and said rebate coupling (46). . The torque transmission axial connection (44) of claim 1, wherein the first and second impellers (38, 40) comprise adjacent stages (18) of the compressor (10). A turbine (14) having a multistage compressor (18) and a multistage turbine (22, 24, 26, 28), characterized in that an axial connection (44) is used between at least two adjacent stages of the compressor and between at least two adjacent stages of the turbine. torque transmitting including intermeshing axially extending teeth (48, 52) with adjacent teeth engaging only along the radial surfaces (64, 66) of said adjacent teeth. The turbine of claim 10, further comprising a rebate coupling (46) between the at least two compressor stages and between the at least * • • · • • « • » • • ·· • · •> • • • • • · • • · • • • • * ·· ··· ·· • ·· ·· two stage turbines. The turbine of claim 10, further comprising corresponding sets of tightening bolts (20, 73) for pulling at least two compressor stages and at least two turbine stages together in an axial direction. 9 9 99 99 • 9 9 9 9 9 * » 9 9 • 9 9 9 9 · '9 9 9 9 • · 99 9 999 9 9 9 99 9 • 9 9 9 9 99 9 Axial compressor 10, gas turbine 12, combustion chamber 14, rotor 16, compressor stage 18, clamping screw 20, impeller 22 gas turbines, impeller 24 gas turbines, impeller 26 gas turbines, impeller 28 gas turbines, distance wheel 30, distance wheel 32, distance wheel axis 36, impeller 38, impeller 40, surface 42, 34, torque-transmitting axial connection 44, radially inner axially centered rebate coupling 46, hinge 48, slot 50, hinge 52, slot 54, radially inner surface 56, flange 60, radially inner surface 62, surface 64, surface 66, tightening screw hole 72 , clamping screw 73,