CN221120124U - Gas turbine main machine box - Google Patents

Abstract

The utility model discloses a gas turbine main machine box body, which comprises: the box frame, set up in the sealing door group of box frame length direction both sides, set up output end plate and exhaust end plate and the roof that sets up in box frame top in box frame length direction both ends, the sealed encapsulation of bottom of box frame is located on the unit chassis. The output end plate is provided with an output port which is used for connecting an output shaft coupler of the generator and extends outwards. The exhaust end plate is provided with an exhaust port which is used for the outward extension of an exhaust pipe for exhausting. The both ends of roof have been seted up the ventilative import that admits air that is used for admitting air to ventilate respectively, and be used for the ventilative export that ventilates of airing exhaust, and the import that admits air sets up near the export end plate side, and ventilative export sets up near the exhaust end plate side. The novel box body is convenient for the model selection of the generator, has small overall size and compact structure, is convenient for installation and transportation, and can also enable the top air inlet ventilation flange to be convenient for installation and smooth ventilation in the box body.

Description

Gas turbine main machine box

Technical Field

The utility model relates to the technical field of gas turbines, in particular to a gas turbine main machine box.

Background

The domestic gas turbine QDR20B is used for the offshore platform, so that the method is an important means for gradually realizing the localization of the domestic gas turbine generator set applied to the offshore platform in China and breaking monopoly of the foreign gas turbine. The offshore platform is used for generating power, the gas turbine unit is in a box body form, and the offshore platform is characterized in that the offshore platform is mainly used for providing protection suitable for salt fog environments for gas turbines and accessories, meeting the requirements of sound insulation, noise reduction, ventilation and air intake of the unit and providing various external interfaces, and the size can be minimized.

The existing gas turbine generator sets with equivalent power for offshore platforms are foreign units and technologies and are not suitable for domestic gas turbines; the existing gas turbine generator set is only applied to land power generation projects before, and cannot meet the use environment requirements of offshore platforms. The total length of the existing unit box assembly body is 9.6 meters, the box assembly body comprises a gas turbine, accessories, a generator and accessories, the middle of the box assembly body is divided into a combustion engine room and a generator room by a partition plate, an output shaft coupler penetrates through the partition plate, and one end of a coupler protection cover is installed on the partition plate. The two sides of a box body of the existing gas turbine generator set are provided with silencing structures, the top of the box body is provided with a gas turbine air inlet, a gas turbine cabin ventilation inlet and outlet, a generator cabin ventilation outlet, an oil mist separator outlet pipe and the like, one end of the box body is a gas turbine exhaust port, the upper part of the other end of the box body is a generator cabin ventilation inlet, and the lower part of the box body is an electrical equipment junction box; the lower part of the box body is connected with a gas turbine installation base, and gas turbine maintenance is carried out from two sides of the box body through special tools without considering the disassembly and maintenance of the generator. The existing box has the following defects:

1) The existing box is only suitable for land gas turbine generator sets, the corrosion protection design cannot meet the requirements of offshore platforms, the existing box is used for installing generators in the box and is only suitable for water-cooled generators and is not suitable for air-cooled generators, the offshore platforms adopt air-cooled generators, and the box structure needs to be redesigned;

2) The existing box body is overlong in size, has more ventilation and air inlet interfaces, and cannot meet the requirements of compact arrangement and size minimization of a unit;

3) The existing box assembly body is divided into a combustion engine room and a generator room, and a partition plate between the two rooms cannot be sealed, so that the division of an explosion-proof area and the equipment model selection are not facilitated;

4) The existing box body is not provided with an observation window, so that the situation in the cabin is inconvenient to observe from the outside at any time;

5) The box body is integrated with various parts such as pipelines, cables, meters, illumination and the like, and most of the prior art is provided with a bracket or a support which is welded according to the need during assembly, so that the appearance is not attractive, and the standardization degree of the parts is not high;

6) The top of the box body is provided with an oil mist separator flange interface, the outlet is directly led out for emptying, the offshore platform does not allow oil gas to be directly emptied, and the oil gas is required to be led to a proper position;

7) The gas turbine maintenance is to remove from both sides of the box body through special tools, which are large in size and inconvenient to store.

Disclosure of utility model

The utility model provides a gas turbine main machine box body, which solves the technical problems that the existing box body is only suitable for a water-cooled generator and an air-cooled engine for an offshore platform, the structure needs to be redesigned, the box body is excessively long in size, ventilation and air inlet interfaces are large, and the requirements of compact arrangement and size minimization of a unit cannot be met.

The technical scheme adopted by the utility model is as follows:

A gas turbine mainframe box applied to an offshore platform for mounting a gas turbine and accessories, the mainframe box comprising: the gas turbine engine comprises a hollow box frame, sealing door groups arranged on two sides of the box frame in the length direction, an output end plate and an exhaust end plate arranged on two ends of the box frame in the length direction, and a top plate arranged on the top end of the box frame, wherein the bottom end of the box frame is hermetically sealed and arranged on an underframe of the gas turbine engine, and the box frame is combined with the underframe of the engine, the two sealing door groups, the output end plate, the exhaust end plate and the top plate to form a hollow and sealed box; the sealing door group is detachably connected with the box frame so as to allow the gas turbine and accessories to go in and out during overhaul; the output end plate is provided with an output port which is used for connecting an output shaft coupler of the generator and extends outwards; the exhaust end plate is provided with an exhaust port which is used for the outward extension of an exhaust pipe for exhausting outwards; the both ends of roof have been seted up the ventilative import that admits air that is used for admitting air to ventilate respectively, and be used for the ventilative export that ventilates of airing exhaust, and the import that admits air sets up near the export end plate side, and ventilative export sets up near the exhaust end plate side.

Further, the sealing door group, the output end plate, the exhaust end plate and the top plate are all double-layer filling sound insulation cotton structures.

Further, the sealing door group comprises a plurality of big doors and small doors, wherein the big doors are sequentially arranged along the length direction of the box frame, and the small doors are arranged on one big door; the upper end and the lower end of the gate post are respectively detachably connected with the box frame; sealing strips are respectively arranged between the outer side surface of the gate and the box frame and between the inner side surface of the gate and the box frame to form a double-layer sealing structure; one of the gates is also provided with perspective glass for outside personnel to observe the conditions in the box.

Further, the main case body also comprises two rainproof edges arranged at two sides of the width direction of the top end of the case frame; the rainproof border box frame extends along the length direction, the inner side edge of the rainproof border is fixed with the long edge of the corresponding side on the box frame, and the opposite outer side edge of the rainproof border box frame extends downwards in a tilting manner and then bends upwards.

Further, the exhaust end plate is made of high-temperature resistant materials, and the outer surface of the exhaust end plate is also coated with high-temperature resistant paint; the connecting pipe connected with the oil tank in the box body is led out to the exhaust port after penetrating through the interlayer of the sealing door group and the exhaust end plate.

Further, the output end plate is formed by splicing two output half end plates split in upper and lower halves along the output port, and the output half end plates are detachably fixed with the box frame.

Further, a partition plate for dividing the air inlet into an air inlet and an air inlet is arranged in the air inlet ventilation inlet, and the air inlet is close to the side of the output end plate; the periphery of the air inlet is provided with an air inlet flange which is arranged on the outer surface of the top plate and the partition plate, the air inlet flange is used for being connected with an external air inlet hose, the air inlet flange is used for being connected with the external air inlet hose, and the lower end of the air inlet is also connected with a flange of an air inlet volute of the gas turbine arranged in the box body; the air inlet is also internally fixed with a first simple hanging beam.

Further, the periphery of the ventilation outlet is also provided with a ventilation flange arranged on the outer surface of the top plate, and the ventilation flange is used for being connected with an external exhaust hose; a second simple hanging beam is also fixed in the ventilation outlet.

Further, the main case assembly further comprises a suspension assembly, wherein the suspension assembly comprises a fixed beam fixed on the lower surface of the top plate along the width direction of the case frame, two movable beams hinged with two ends of the fixed beam respectively, a limiting block arranged at the free end of the movable beam and used for preventing the trolley from sliding out of the movable beam, a first fastening piece used for fixing the movable beam with the top plate when the movable beam is not required to be used, and a second fastening piece used for fixing the movable beam when the movable beam is connected with the fixed beam in a same line; the first fastener and the second fastener are respectively arranged on the top plate.

Further, a plurality of mounting steel bars which are distributed and arranged for wiring and have a C-shaped section are also fixed on the box frame; a plurality of embedded steel pipes for outgoing lines are also embedded in the top plate.

The utility model has the following beneficial effects:

In the main case body, only the gas turbine and accessories are contained in the case body, so that the shape selection of the generator is facilitated, the whole case body design cannot be influenced due to the change of the external dimensions (such as a cooling mode, explosion prevention and the like), positive pressure design can be carried out in the case body, the explosion prevention area is arranged in the case body, the non-explosion prevention area is arranged outside the case body, and the case body is small in size, compact in structure and convenient to install and transport; in the main case body, the two ends of the top plate are respectively provided with the air inlet ventilation inlet and the air ventilation outlet, the air inlet ventilation inlet is arranged close to the output end plate side, and the air ventilation outlet is arranged close to the exhaust end plate side; in the main machine box body, the sealing door group is detachably connected with the box frame, so that the gas turbine and accessories can conveniently enter and exit during overhauling.

In addition to the objects, features and advantages described above, the present utility model has other objects, features and advantages. The present utility model will be described in further detail with reference to the drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. In the drawings:

FIG. 1 is a schematic illustration of a gas turbine engine case in accordance with a preferred embodiment of the present utility model;

FIG. 2 is a second schematic illustration of a gas turbine engine case in accordance with a preferred embodiment of the present utility model;

FIG. 3 is a bottom view of a gas turbine main case assembly of a preferred embodiment of the present utility model.

Description of the drawings

10. A box frame; 20. sealing the door group; 21. a gate; 22. a small door; 30. an output end plate; 301. an output port; 40. an exhaust end plate; 401. an exhaust port; 50. a top plate; 501. an air inlet; 502. an air inlet; 503. a ventilation outlet; 51. a partition plate; 52. a first simple hanging beam; 53. a second simple hanging beam; 61. perspective glass; 62. rain-proof edges; 63. installing steel bars; 64. embedding a steel pipe; 70. a suspension assembly; 71. a fixed beam; 72. a movable beam; 73. a limiting block; 74. a first fastener; 75. and a second fastener.

Detailed Description

Embodiments of the utility model are described in detail below with reference to the attached drawing figures, but the utility model can be practiced in a number of different ways, as defined and covered below.

Referring to FIGS. 1-2, a preferred embodiment of the present utility model provides a gas turbine main housing for use on an offshore platform for mounting a gas turbine and accessories, the main housing comprising: the box frame 10 of well box form, set up in the sealed door group 20 of box frame 10 length direction both sides, set up in the output end plate 30 and the exhaust end plate 40 of box frame 10 length direction both ends and set up in the roof 50 on box frame 10 top, the bottom seal of box frame 10 is located on the gas turbine unit chassis, and box frame 10 combines unit chassis, two sets of sealed door group 20, output end plate 30, exhaust end plate 40 and roof 50 to form hollow and sealed box. The sealing door set 20 is detachably connected with the box frame 10 for access during maintenance of the gas turbine and accessories. The output end plate 30 is provided with an output port 301 for the output shaft coupling of the generator to extend outwards. The exhaust end plate 40 is provided with an exhaust port 401 through which an exhaust pipe for exhausting outward extends. The two ends of the top plate 50 are respectively provided with an air inlet and ventilation inlet and an air outlet 503 for air inlet and ventilation, the air inlet and ventilation inlet are arranged near the output end plate 30 side, and the air outlet 503 is arranged near the exhaust end plate 40 side.

In the main case body, only the gas turbine and accessories are contained in the case body, so that the shape selection of the generator is facilitated, the whole case body design cannot be influenced due to the change of the external dimensions (such as a cooling mode, explosion prevention and the like), positive pressure design can be carried out in the case body, the explosion prevention area is arranged in the case body, the non-explosion prevention area is arranged outside the case body, and the case body is small in size, compact in structure and convenient to install and transport; in the main case body, the two ends of the top plate 50 are respectively provided with the air inlet ventilation inlet and the air ventilation outlet 503, the air inlet ventilation inlet is arranged close to the side of the output end plate 30, and the air ventilation outlet 503 is arranged close to the side of the exhaust end plate 40; in the main machine box body, the sealing door group 20 is detachably connected with the box frame 10, so that the gas turbine and accessories can conveniently enter and exit during overhauling.

In this alternative scheme, as shown in fig. 1, the size of the box body is 4360mm (length) ×2348mm (width) ×2515mm (height), the gas turbine and accessories thereof are protected, the positive pressure design is carried out in the box body, an explosion-proof area is arranged in the box body, a non-explosion-proof area is arranged outside the box body, the box body adopts a frame structure welded by rectangular pipe groups, the bottom of the box body is arranged on a machine unit underframe, and the box body is sealed by bolts and sealing strips.

Optionally, as shown in fig. 1, the sealing door set 20, the output end plate 30, the exhaust end plate 40 and the top plate 50 are all of double-layer filled sound insulation cotton structure, so as to reduce the noise of the unit below 85dB (a) (1 m outside the unit, 1.2m above the ground).

Alternatively, as shown in fig. 1, the sealing door group 20 includes a plurality of gates 21 disposed in sequence along the length direction of the box frame 10, and a small gate 22 disposed on one of the gates 21. The upper and lower ends of the gate post of the gate 21 are detachably connected with the box frame 10 respectively; in this alternative, each side includes three gates 21, gate 21 and gate post are all removable, and each side headroom is not less than 4000mm (long) after demolishing for maintenance of the gas turbine inlet and outlet box. Sealing strips are respectively arranged between the outer side surface of the gate 21 and the box frame 10 and between the inner side surface of the gate 21 and the box frame 10 to form a double-layer sealing structure, so that the sealing of the box body is ensured. One of the gates 21 is also provided with a perspective glass 61 for outside personnel to observe the conditions in the box; in this alternative, the perspective glass 61 is a double-layer vacuum glass, and an outside person can conveniently observe the internal condition of the case when the gas turbine is running, and also has a condition of preventing malfunction of the detector in the case due to factors outside the case.

Optionally, as shown in fig. 1, the main chassis assembly further includes two rain-proof edges 62 disposed on both sides of the top width direction of the chassis frame 10. The rain-proof edge 62 extends along the length direction of the box frame 10, and the inner side edge of the rain-proof edge 62 is fixed with the long edge of the corresponding side on the box frame 10, the opposite outer side edge of the rain-proof edge extends downwards in a slanting manner and then bends upwards, and the rain-proof edge 62 is used for preventing rainwater from entering the box body through the sealing door set 20.

Alternatively, as shown in fig. 2, the exhaust end plate 40 is formed of a high temperature resistant material, and is further coated with a high temperature resistant paint on its outer surface. The connecting pipe connected with the oil tank in the box body is penetrated in the interlayer of the sealing door group 20 and the exhaust end plate 40 and then led out to the exhaust port 401, so that the oil mist of the oil mist separator is discharged along with tail gas, and the top of the box body is prevented from being emptied.

Alternatively, as shown in fig. 1, the output end plate 30 is formed by splicing two output half end plates split up and down along the output port 301, and the output half end plates are detachably fixed with the box frame 10, so that the output shaft coupling and the protective cover are convenient to install and remove, and the outer side of the output end plate 30 and the generator are sealed by a protective cover through flange surfaces.

Optionally, as shown in fig. 1, a partition plate 51 for dividing the inlet into an air inlet 501 and an air inlet 502 is provided in the inlet ventilation inlet, and the air inlet 501 is near the output end plate 30 side. The periphery of the air inlet 501 is provided with an air inlet flange arranged on the outer surface of the top plate 50 and the partition plate 51, the periphery of the air inlet 502 is provided with an air inlet flange arranged on the outer surface of the top plate 50 and the partition plate 51, the air inlet flange is used for being connected with an external air inlet hose, the air inlet flange is used for being connected with the external air inlet hose, the lower end of the air inlet 502 is also connected with a flange of an air inlet volute of the gas turbine arranged in the box body, and the air inlet part directly leads to the box body; the structural design not only can meet the requirements of gas turbine gas inlet and ventilation, but also can ensure that the size of the box body is minimum, and simultaneously can ensure that the top gas inlet flange and the gas inlet flange are convenient to install and the ventilation in the box body is smooth. A first simple hanging beam 52 is also fixed in the air inlet 501 and is used for maintaining the coupling of the output shaft of the gas turbine.

Optionally, as shown in fig. 1, the ventilation outlet 503 is further provided with a ventilation flange disposed on the outer surface of the top plate 50, and the ventilation flange is used for connecting with an external exhaust hose. A second simple hanging beam 53 is also fixed in the ventilation outlet 503 for maintenance of the exhaust end of the gas turbine.

Optionally, as shown in fig. 3, the main chassis box further includes a suspension assembly 70, the suspension assembly 70 including a fixed beam 71 fixed to a lower surface of the top plate 50 in a width direction of the chassis frame 10, two movable beams 72 hinged to both ends of the fixed beam 71, a stopper 73 provided at a free end of the movable beam 72 for preventing the trolley from sliding out of the movable beam 72, a first fastener 74 for fixing the movable beam 72 to the top plate 50 when the movable beam 72 is not in use, and a second fastener 75 for fixing the movable beam 72 when the movable beam 72 is connected in-line with the fixed beam 71. The first fastener 74 and the second fastener 75 are provided on the top plate 50, respectively. In this alternative, the first fastening member 74 and the second fastening member 75 are fastening screws, and the fastening screws penetrate through the top plate 50 and then connect with the corresponding movable beams 72, thereby fixing the movable beams 72 at a defined position. When the gas turbine is in operation, three H-shaped steel arranged at the top of the gas turbine, namely a fixed beam 71 and two movable beams 72, are used as tools for the gas turbine to enter and exit the box body, wherein the middle H-shaped steel is directly welded at the box top, the H-shaped steel of which the two sides extend out of the box body is designed into a rotatable structure, and when the gas turbine is not in use, the gas turbine is rotated for 90 degrees and is vertical to the middle H-shaped steel, and the free end of the gas turbine is fixed at the box top by a first fastener 74; when the gas turbine is used, the gas turbine is rotated to be collinear with the middle H-shaped steel, the rotation position is limited by a second fastener 75, and the gas turbine can be transported out of the box body by the travelling trolley, and a limiting block 73 is arranged at the free end of the movable beam 72 and used for preventing the travelling trolley from sliding out of the movable beam 72.

Optionally, as shown in fig. 1, in order to facilitate the installation of accessories such as a cable bridge, a pipeline, an instrument, a lighting device, a detector, and the like, a plurality of installation steel bars 63 which are arranged in a scattered manner and are used for wiring and have a C-shaped section are fixed on the box frame 10, so that the interference condition during crossing is avoided, the standardization rate of parts is improved, and the standardized design of a unit is facilitated. A plurality of embedded steel pipes 64 for outgoing lines are embedded in the top plate 50, so that the problem that the sound insulation layer of the top plate is damaged by direct outgoing lines is avoided, and the sealing problem of the oversized box body with concentrated outgoing line openings is simplified.

Optionally, after the whole box body is welded, paint treatment is carried out according to CX standard requirements, so that corrosion at the places where surface treatment cannot be carried out is avoided, the whole box body is welded fully, and the places where deformation is easy to occur are reinforced by adding reinforcing ribs; through holes cannot be formed in all the closed cavities, so that salt spray corrosion is avoided in the cavities; all removable parts and accessories that cannot be painted use a zinc-impregnated member.

The utility model is designed for realizing that the 2MW gas turbine generator set is applied to an offshore platform, providing protection applicable to salt fog environment for a gas turbine and accessories thereof, reducing the noise of the generator set to be below 85dB (1 m outside the generator set and 1.2m above the ground), and meeting the ventilation and air intake requirements of the generator set. The utility model fills the application blank of the domestic small-sized gas turbine generator set in the offshore platform by utilizing the QDR20B gas turbine generator set, and the QDR20B gas turbine generator set is applied to the offshore platform as the domestic small-sized gas turbine with the power of 2000 kW.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (10)

1. A gas turbine mainframe box for use on an offshore platform for mounting a gas turbine and accessories, the mainframe box comprising:

The gas turbine unit comprises a hollow box-shaped box frame (10), sealing door groups (20) arranged on two sides of the box frame (10) in the length direction, an output end plate (30) and an exhaust end plate (40) arranged on two ends of the box frame (10) in the length direction, and a top plate (50) arranged on the top end of the box frame (10), wherein the bottom end of the box frame (10) is hermetically arranged on a gas turbine unit underframe, and the box frame (10) is combined with the unit underframe, the two sealing door groups (20), the output end plate (30), the exhaust end plate (40) and the top plate (50) to form a hollow and sealed box;

The sealing door group (20) is detachably connected with the box frame (10) so as to allow the gas turbine and accessories to go in and out during overhauling;

An output port (301) for the output shaft coupler connected with the generator to extend outwards is formed in the output end plate (30);

An exhaust port (401) which is used for the outward extension of an exhaust pipe for exhausting is arranged on the exhaust end plate (40);

The two ends of the top plate (50) are respectively provided with an air inlet ventilation inlet and an air ventilation outlet (503), wherein the air inlet ventilation inlet and the air ventilation outlet are used for air inlet ventilation, the air inlet ventilation inlet is arranged close to the side of the output end plate (30), and the air ventilation outlet (503) is arranged close to the side of the exhaust end plate (40).

2. The gas turbine main engine case of claim 1, wherein,

The sealing door group (20), the output end plate (30), the exhaust end plate (40) and the top plate (50) are all of double-layer filling sound insulation cotton structures.

3. The gas turbine main engine case of claim 1, wherein,

The sealing door group (20) comprises a plurality of big doors (21) which are sequentially arranged along the length direction of the box frame (10), and small doors (22) which are arranged on one big door (21);

The upper end and the lower end of a gate post of the gate (21) are respectively detachably connected with the box frame (10);

Sealing strips are respectively arranged between the outer side surface of the gate (21) and the box frame (10) and between the inner side surface of the gate (21) and the box frame (10) to form a double-layer sealing structure;

one of the gates (21) is also provided with a perspective glass (61) for outside personnel to observe the conditions in the box.

4. The gas turbine main engine case of claim 1, wherein,

The main case body also comprises two rainproof edges (62) arranged on two sides of the top end of the case frame (10) in the width direction;

The rainproof edge (62) extends along the length direction of the box frame (10), the inner side edge of the rainproof edge (62) is fixed with the long edge of the corresponding side on the box frame (10), and the opposite outer side edge of the rainproof edge extends downwards in a tilting manner and then bends upwards.

5. A gas turbine main tank as claimed in claim 2, wherein,

The exhaust end plate (40) is made of high-temperature resistant material, and the outer surface of the exhaust end plate is also coated with high-temperature resistant paint;

the connecting pipe connected with the oil tank in the box body is penetrated in the interlayer of the sealing door group (20) and the exhaust end plate (40) and then led out to the exhaust port (401).

6. The gas turbine main engine case of claim 1, wherein,

The output end plate (30) is formed by splicing two output half end plates split in an upper half and a lower half along the output port (301), and the output half end plates are detachably fixed with the box frame (10).

7. The gas turbine main engine case of claim 1, wherein,

A partition plate (51) for dividing the air inlet into an air inlet (501) and an air inlet (502) is arranged in the air inlet ventilation inlet, and the air inlet (501) is close to the side of the output end plate (30);

An air inlet flange arranged on the outer surface of the top plate (50) and the partition plate (51) is arranged on the periphery of the air inlet (501), an air inlet flange arranged on the outer surface of the top plate (50) and the partition plate (51) is arranged on the periphery of the air inlet (502), the air inlet flange is connected with an external air inlet hose, the air inlet flange is connected with the external air inlet hose, and the lower end of the air inlet (502) is also connected with a flange of an air inlet volute of the gas turbine arranged in the box body;

The air inlet (501) is also internally fixed with a first simple hanging beam (52).

8. The gas turbine main engine case of claim 1, wherein,

The periphery of the ventilation outlet (503) is also provided with a ventilation flange arranged on the outer surface of the top plate (50), and the ventilation flange is used for being connected with an external exhaust hose;

A second simple hanging beam (53) is also fixed in the ventilation outlet (503).

9. The gas turbine main engine case of claim 1, wherein,

The main box body further comprises a suspension assembly (70), wherein the suspension assembly (70) comprises a fixed beam (71) fixed on the lower surface of the top plate (50) along the width direction of the box frame (10), two movable beams (72) hinged with two ends of the fixed beam (71) respectively, a limiting block (73) arranged at the free end of the movable beam (72) and used for preventing the trolley from sliding out of the movable beam (72), a first fastener (74) used for fixing the movable beam (72) with the top plate (50) when the movable beam (72) is not needed to be used, and a second fastener (75) used for fixing the movable beam (72) when the movable beam (72) is connected with the fixed beam (71) in a same line;

The first fastener (74) and the second fastener (75) are respectively arranged on the top plate (50).

10. The gas turbine main engine case of claim 1, wherein,

A plurality of mounting steel bars (63) which are distributed and arranged for wiring and have a C-shaped section are also fixed on the box frame (10);

A plurality of embedded steel pipes (64) for outgoing lines are also embedded in the top plate (50).