Improved clutch box for hybrid train applications

Abstract

A hybrid train system is disclosed. The hybrid train system includes at least one gas turbine and a clutch box. The clutch box includes a torque limiting device disposed within a storage case of the clutch box itself. When the torque transmitted to the clutch exceeds a threshold value, the torque limiting device mechanically disengages the clutch from the gas turbine. A clutch box is also disclosed.

Description

Technical Field

[0001] The present disclosure relates to an improved clutch box system for hybrid train applications.

Background Art

[0002] Gas turbines are often used to provide torque to loads such as compressors, for example in the field of liquefied natural gas and generally in the oil and gas industry. A gas turbine is typically connected via a shaft to a load such as the compressor, pump, or any rotating equipment described above.

[0003] More specifically, referring to liquefied natural gas (LNG) processing, LNG is liquefied by a liquefaction process in which natural gas is cooled using a refrigeration cycle and as a result becomes a liquid for storage and transportation.

[0004] To cool the LNG, a refrigerant is cooled by a compressor and then the refrigerant is condensed and expanded to remove heat from the natural gas flowing through the heat exchanger. The compressor is typically driven by a gas turbine.

[0005] In recent years, electric machines have also been included in the above layout. A configuration in which a gas turbine, a load, and an electric machine are present along a shaft line is commonly known and is called a hybrid train configuration, a hybrid train system, a hybrid turbo compressor train, or simply a hybrid train. In such a configuration, the electric machine can operate as an electric motor such as a helper, for example to alternatively supply torque to a load (e.g., a compressor) when the gas turbine cannot operate, or to directly supply torque to the gas turbine, for example during a startup phase.

[0006] The electromechanical machine can also operate as a generator, for example, when the gas turbine generates more power than is normally required by the load. In this case, the power is converted into electrical energy by the electromechanical machine and injected, for example, into the public power grid.

[0007] Since the gas turbine and the electromechanical machine usually have different operating speeds and inertial forces, problems of transmitted torque arise when designing the hybrid train.

[0008] A first solution to address such technical design problems is to overdesign the shafts connecting the different components of the hybrid train, namely the gas turbine, the load, and the electric motor. However, this design approach has proven to be expensive. Also, between the gas turbine and the electromechanical machine, and between the electromechanical machine and the load, remotely controllable clutches are usually installed. The clutch enables the disconnection of different mechanical components of the hybrid train configuration. Usually, the hybrid train includes a clutch to facilitate the transmission of power from the gas turbine (or from the electromechanical machine) to the load. The clutch enables easier transmission of torque via the shaft.

[0009] Finally, as a good design practice, the hybrid train includes a torque limiting device (TLD) installed upstream of each connection, i.e., the clutch. The TLD is an automatic device aimed at protecting the mechanical components from damage that can occur in case of mechanical overload. More specifically, the TLD can limit torque in several ways. In a first example, the TLD can limit torque by slipping, as in the case of a friction plate slip clutch, or by disconnecting the load, as in the case of a shear pin type TLD. In the latter case, a mechanical component, i.e., the shear pin, is sacrificed to disconnect the moving and overloaded shaft.

[0010] The TLD installed within the coupling requires a suitable landing device that can enable a safe shutdown of the unit in the event of TLD intervention. Such a coupling between the TLD and the landing device is much heavier than a normal coupling, and as a result, the dynamic influence of the rotor on the driving and driven equipment / machinery occurs. As a result, the coupling can be selected according to the normal method (without TLD).

[0011] This means severe dynamic restrictions of the rotor on the compressor design and on the train operating range due to the heavier coupling. Also, a feasibility study is necessary to evaluate each train shaft line or the electro-mechanical rated torque to enable the accurate operation of the system. Furthermore, the detection of TLD intervention is more difficult.

[0012] Therefore, an improved torque transmission by a clutch would be welcomed in the art. More generally, it is desirable to provide a torque transmission mechanism that enables a reduction in the complexity and overall cost of a hybrid train. SUMMARY OF THE INVENTION

[0013] In one aspect, the subject matter disclosed herein relates to a hybrid train system having a load, such as a compressor or a pump driven by torque, and a gas turbine for generating a driving torque. The hybrid train system also includes a main transmission assembly having a clutch box. The clutch box has a storage case and a clutch. A first transmission shaft is mechanically connected at one end to the gas turbine and at the other end to the clutch box. A second transmission shaft is mechanically connected at one end to the clutch box. The clutch box includes a torque limiting device disposed within the storage case, and the torque limiting device is connected between the clutch and the first transmission shaft and / or the second transmission shaft, and when the torque transmitted to the clutch exceeds a threshold value, the torque limiting device is adapted to mechanically disconnect the clutch from the first transmission shaft and / or the second transmission shaft.

[0014] In another aspect, the subject matter disclosed herein relates to a torque limiting device having a body, a collar rotatably connected to a first transmission shaft, a sprocket rotatably connected to the clutch and disposed opposite the collar, and a shear pin connecting the collar and the sprocket. The shear pin is subjected to a shearing force when torque is transmitted from the collar to the sprocket. When the transmitted torque causes a force exceeding the shear strength threshold of the shear pin, the shear pin breaks and mechanically disconnects the gas turbine.

[0015] A further aspect of the present invention is directed to the fact that the clutch includes a first clutch disk connected to the first transmission shaft and a second clutch disk connected to the second transmission shaft. The second transmission shaft may be connected to the load.

[0016] In another aspect, the subject matter disclosed herein relates to a hybrid train system that includes an electromechanical machine and a further transmission assembly that mechanically connects the electromechanical machine and a load. The electromechanical machine can operate as both a motor and a generator.

[0017] In another aspect, the subject matter disclosed herein relates to a hybrid train system that includes an electromechanical machine. A second transmission shaft is connected to the electromechanical machine. The hybrid train system also includes an additional clutch box, a first transmission shaft having one end mechanically connected to the electromechanical machine and the other end mechanically connected to the clutch box, and a second transmission shaft having one end mechanically connected to the electromechanical machine and the other end mechanically connected to the load, and further includes a transmission assembly.

Brief Description of the Drawings

[0018] Many of the disclosed embodiments of the present invention, and the attendant advantages thereof, will be better understood and readily appreciated when considered in connection with the accompanying drawings, by reference to the following detailed description of the invention for carrying out the invention, a complete understanding will be easily obtained.

Figure 1

Figure 2

Figure 3

Figure 4

Detailed Description of the Invention

[0019] A gas turbine is used to drive loads such as a compressor connected to a shaft. In recent years, a so-called hybrid train system that also integrates an electric machine has become widespread in the market. The torque transmission of the hybrid train system is connected by a clutch, enabling smooth torque transmission between components with different operating speeds.

[0020] According to one aspect, the present subject matter is directed to a clutch box that integrates a torque limiting device, such that the torque limiting device can have both a function of protecting to enable a safe shutdown of the unit in case of intervention and a function of a stabilizer installed at a specific position instead of the stabilizing weights usually used in a normal clutch. Therefore, the TLD in the clutch box, which requires additional mass to stabilize the shaft between bearings, does not cause dynamic drawbacks of the rotor.

[0021] Referring now to the drawings, FIG. 1 shows a hybrid train system 1 according to Embodiment 1. The hybrid train system 1 includes a gas turbine 2 and a load 3 driven by the gas turbine 2.

[0022] The gas turbine 2 includes a gas compressor 21 capable of compressing air from the environment, and this compressed air is delivered to a combustor 22. In the combustor 22, fuel is added to the air stream to form a fuel / air mixture gas, which is then ignited. The combustion gas generated in the combustor is delivered to a high-pressure turbine 23, where it expands partially to generate mechanical power. The mechanical power generated by the high-pressure turbine 23 is used to drive the gas generator compressor 21.

[0023] The load 3 is connected to the gas turbine by the transmission assembly 4. Specifically, the main transmission assembly 4 includes a first transmission shaft 41 with one end connected to the gas turbine 2, a second transmission shaft 42 with one end connected to the load 3, and a clutch box 5. In the illustrated layout of the hybrid train system 1, the clutch box 5 is connected to the first transmission shaft 41 and the second transmission shaft 42.

[0024] Two clutch disks 521 and 522 are schematically shown inside the clutch box 5, and are mechanically connected to the other end of the main transmission shaft 41 and the other end of the second transmission shaft 42 respectively. The clutch disks 521 and 522 are capable of participating in the transmission of power. The two clutch disks 521, 522 are stored in the storage case 51.

[0025] The hybrid train system 1 also includes an electromechanical machine 6 mechanically connected to the load 3 by a shaft 7, and the shaft 7 includes only the second shaft in this case. The electromechanical unit 6 can operate either to provide torque to the load 3 as an electric motor or to convert the torque received via the shaft 7 into electric power as a generator.

[0026] In the illustrated embodiment, the load is a compressor, but in other embodiments, the load can be a different load such as a pump.

[0027] Referring to FIGS. 2 and 3 here, a longitudinal cross-section of the clutch box 5 shown in more detail is shown. In particular, it can be seen that the clutch box 5 is provided with a support structure 53 for supporting the entire weight of the clutch box 5 itself and the first transmission shaft 41 and the second transmission shaft 42 connected to the clutch box 5. The clutch box 5 also includes a clutch 52, and as already described above, the clutch 52 includes two clutch disks 521 and 522 respectively connected to the first transmission shaft 41 and the second transmission shaft 42. The clutch 52 has a function of disconnecting the power transmission between the first transmission shaft 41 and the second transmission shaft 42 and mechanically disconnecting the gas turbine 2 from the clutch 52.

[0028] The clutch box 5 also includes a plurality of combined thrust bearings 54 arranged in the storage case 51. Specifically, in this embodiment, the number of the combined thrust bearings 54 is 4. The combined thrust bearings 541 and 542 are fixed to the support structure 53 and connected to the first transmission shaft 41, and the other two combined thrust bearings 543 and 544 are fixed to the support structure 53 and connected to the second transmission shaft 42.

[0029] The clutch box 5 also includes a torque limiting device 55 connected between the first transmission shaft 41 and the clutch disk 521 of the clutch 52. The torque limiting device 55 includes a main body 551, two journal bearings 552 each having an outer ring 5521 and an inner ring 5522 facing each other, and a plurality of spheres 5523 rolling between them.

[0030] The body 551 is connected to the journal bearing 552 and has a collar 5511 that rotates with it. A sprocket 5512 is connected to the clutch disk 521. The collar 5511 and the sprocket 5512 face each other and are connected by one or more shear pins 553. Thus, the shear pin 553 connects two rotating members, namely the collar 5511 and the sprocket 5512, and receives a shear force during torque transmission. It can be seen that the torque limiting device 55 is completely housed within the clutch box 5.

[0031] The introduction of the torque limiter device 55 makes it possible to avoid overdesign of the shaft line, which may limit the operating range of the hybrid train system 1. In fact, the mass of the torque limiter device 55 stabilizes the main shaft assembly 4 between the combined thrust bearings 543 and 544, thus preventing dynamic drawbacks of the rotor. The mass of the torque limiter device 55 replaces the normal mass applied to the shaft for shaft stabilization.

[0032] Specifically, in the clutch box 5, only the radial bearings support the weight of the rotor. All of these bearings are hydrodynamic sleeve bearings with a single combined thrust surface and need to operate under load for stabilization. Therefore, the stiffness and damping coefficients of the bearings are greatly affected by the load. To ensure that the bearings provide a minimum surface pressure and as the best way to stabilize, usually a mass is added between the two bearings of each shaft. Furthermore, in the case of high exceptional torque, a shaft with a larger minimum cross-sectional diameter will be used than when the torque is limited by the torque limiting device 55. Therefore, the diameters of the bearings 541, 542, 543, and 544 are directly related to the pick torque. The larger the diameter of the bearing, the lower the surface pressure of the bearing. Therefore, there is a strong interest in limiting exceptional torque to ensure the stability of the bearings by applying sufficient load to the bearings.

[0033] In other embodiments, other types of torque limiting devices, such as torque locker types, etc., can be installed.

[0034] The hybrid train system 1 according to Embodiment 1 described above operates as follows.

[0035] When the gas turbine 2 operates, torque can be transmitted to the load 3 by the clutch 5, and the load 3 is a compressor. The two clutch disks 521 and 522 of the clutch can be separated from each other, in which case torque is not transmitted to the load 3. When the clutch disks 521 and 522 are connected, torque can be transmitted from the gas turbine 2 to the load 3, and the shear pin 553 receives a shear force. Then, the first transmission shaft 41 and the second transmission shaft 42 rotate, for example, according to the rotation arrow R (see FIG. 1).

[0036] When the transmitted torque causes a force that exceeds the shear strength of the pin, that is, a specific shear strength that can be preset by appropriate design, the shear pin 553 breaks, and the gas turbine 2 and the load 3 are mechanically disconnected.

[0037] Referring now to FIG. 4, an embodiment 2 of the drive unit 1' is shown. In this case, a different layout having two clutch boxes 5 is shown, as will be described in more detail below.

[0038] The hybrid train system 1' includes a gas turbine 2 and an electric motor 6 connected by a first clutch box 5 similar to the clutch box of Embodiment 1. The two clutch disks 521 and 522 of the clutch 52 are respectively connected to the first transmission shaft 41 and the second transmission shaft 42.

[0039] The load 3 is connected to the electromechanical machine 6 by a transmission assembly 8 having a clutch box 5 similar to the clutch box of Embodiment 1 of the hybrid train system 1 described above.

[0040] A further transmission assembly 8 includes a first transmission shaft 81, a second transmission shaft 82, and a clutch box 52. Two clutch disks 521 and 522 of the clutch 52 of the second clutch box 5' provided in the further transmission assembly 8 are connected to the first transmission shaft 81 and the second transmission shaft 82, respectively.

[0041] In the hybrid train system 1', the electromechanical machine 6 can operate as a helper to provide torque to the load 3 or as a generator that converts excess power generated by the gas turbine 2 and not required by the load 3 into electrical energy injected into, for example, the power grid G to which the electromechanical machine 6 can be connected.

[0042] In the hybrid train system 1', both the first clutch box 5 and the second clutch box 5' can break according to the same mechanism as that disclosed for the hybrid train system 1 according to Embodiment 1 when the gas turbine 2 or the electromechanical machine 6, or both, generate excessive torque on the transmission assemblies 4 and 8.

[0043] Thus, when the transmitted torque causes a force that exceeds the shear strength of the pin, i.e., a specific shear strength that can be preset by appropriate design, the shear pin 553 breaks and the gas turbine 2 or the load 3 is mechanically disconnected.

[0044] The advantage of implementing a torque limiter device is the advantage of being able to avoid overdesign of the shaft line, which, if such overdesign were to occur, could endanger the project's feasibility or limit the operating range of the turbocompressor train. Also, the shaft line is standardized regardless of the mechanical and electrical parameters of the electromechanical machine, i.e., regardless of the manufacturer. Therefore, a standardized train shaft line with the above characteristics, developed for a brownfield solution, can be easily replicated in a greenfield solution.

[0045] Another advantage of the present disclosure is the dynamic benefit of the rotor in both the design of the electromechanical machine and the compressor. Also, an enhanced operating mode spectrum (including "booster mode") is available.

[0046] A further advantage of the present disclosure is that the clutch box can be used in brownfield and greenfield solutions. Also, the validity of the shaft line can be easily confirmed without conducting a detailed feasibility study.

[0047] Also, an advantage of the present disclosure is obtaining standardized shaft line integration regardless of the electromechanical machine manufacturer, which may result in a commercial benefit.

[0048] Although aspects of the invention have been described with respect to various specific embodiments, it will be apparent to those skilled in the art that many modifications, changes, and omissions are possible without departing from the spirit and scope of the claims. Additionally, unless otherwise specified herein, the order or arrangement of any process or method steps may be changed or rearranged according to alternative embodiments.

[0049] Detailed reference has been made to embodiments of the present disclosure, and one or more of these examples are illustrated in the drawings. Each example is provided as an illustration of the present disclosure and not as a limitation thereof. It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope or spirit of the present disclosure. References throughout this specification to "one embodiment" or "an embodiment" or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosed subject matter. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Also, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0050] When presenting elements of various embodiments, the articles "a", "an", "the", and "said" are intended to mean that there is one or more of the elements. The terms "comprising", "including", and "having" are intended to be non-exclusive and mean that additional elements other than the listed elements may exist.

Claims

1. A load driven by torque, a gas turbine that generates a driving torque for driving the load, and a main transmission assembly, a clutch box including a storage case and a clutch disposed within the storage case, a first transmission shaft having one end mechanically connected to the gas turbine and the other end mechanically connected to the clutch box, and a second transmission shaft having one end mechanically connected to the clutch box, A hybrid train system comprising a main transmission assembly having, The clutch box includes a torque limiting device disposed within the storage case, The torque limiting device is connected between the clutch and the first transmission shaft and / or the second transmission shaft, When the torque transmitted to the clutch exceeds a threshold value, the torque limiting device mechanically disengages the clutch from the first transmission shaft and / or the second transmission shaft. A hybrid train system.

2. The torque limiting device includes a body, a collar rotatably connected to the first transmission shaft, a sprocket rotatably connected to the clutch and disposed opposite the collar, one or more shear pins connecting the collar and the sprocket so as to receive a shear force when torque is transmitted from the collar to the sprocket, including When the transmitted torque causes a force exceeding the shear strength threshold of the shear pin, the shear pin breaks and mechanically disengages the gas turbine. The hybrid train system according to claim 1.

3. The clutch includes a first clutch disk connected to the first transmission shaft and a second clutch disk connected to the second transmission shaft. The hybrid train system according to claim 1.

4. The collar is connected to the first transmission shaft by a journal bearing, The sprocket is connected to the second shaft by a journal bearing. The hybrid train system according to claim 3.

5. The other end of the second transmission shaft is connected to the load, the hybrid train system according to claim 3.

6. An electromechanical machine and a further transmission assembly for mechanically connecting the electromechanical machine and the load, the electromechanical machine being configured to operate as an electric motor to transmit torque to the load and to operate as a generator to receive torque from the load, the hybrid train system according to claim 1.

7. Comprising an electromechanical machine, The second transmission shaft is connected to the electromechanical machine, The hybrid train system is a further transmission assembly, An additional clutch box, A first transmission shaft having one end mechanically connected to the electromechanical machine and the other end mechanically connected to the clutch box, A second transmission shaft having one end mechanically connected to the electromechanical machine and the other end mechanically connected to the load, the hybrid train system according to claim 3 comprising a further transmission assembly having the same.

8. The load is a compressor or a pump, the hybrid train system according to claim 1.

9. A storage case, A clutch disposed within the storage case, A clutch box comprising the same, The clutch box comprises a torque limiting device disposed within the storage case, The torque limiting device is connectable between the first transmission shaft and the clutch, When the torque transmitted to the clutch exceeds a threshold value, the torque limiting device mechanically disengages the clutch from the first transmission shaft, the clutch box.

10. The torque limiting device, A main body, A collar rotatably connectable to the first transmission shaft, A sprocket rotatably connected to the clutch and disposed opposite the collar, One or more shear pins connecting the collar and the sprocket so as to receive a shear force when torque is transmitted from the collar to the sprocket, When the transmitted torque causes a force exceeding the shear strength threshold of the shear pin, the shear pin breaks and mechanically disengages the clutch, the clutch box according to claim 9.

11. The color can be connected to the first transmission shaft by a journal bearing, The hybrid train system according to claim 9, wherein the sprocket can be connected to the second shaft by a journal bearing.

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