Detachable heat shield for lateral air inlet low-pressure inner cylinder

Abstract

The invention discloses a detachable heat shield for a lateral air inlet low-pressure inner cylinder, and relates to the technical field of steam turbines. The problems that an existing heat shield is provided with a thick heat preservation interlayer and is fixed through a large number of bolts and steel wires or glue, the heat preservation structure is often not detachable, and a unit is inconvenient to overhaul are solved. The whole heat shield adopts an upper and lower half structure according to the outer contour of the low-pressure inner cylinder and an upper and lower half split structure form, and is totally divided into five parts in order to be convenient to disassemble and assemble, and the parts are connected through bolts, so that the disassembly and assembly are convenient, and the maintenance of a unit is convenient; the heat shield is mainly used for preventing exhaust from directly contacting with the outer surface of the low-pressure inner cylinder, cooling the outer wall of the inner cylinder and reducing the temperature difference between the inner and outer surfaces of the inner cylinder; therefore, thermal stress and deformation of the inner cylinder are reduced, the strength performance of the inner cylinder is improved, and the service life is prolonged. The whole peripheries of the heat shield and the outer wall of the inner cylinder are connected through a plurality of bolts, and the heat shield is prevented from being damaged due to unstable airflow resonance. The invention is applicable to the technical field of turbines.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbines, and in particular to a detachable heat insulation cover for a side-intake low-pressure inner cylinder. Background Art

[0002] When designing the low-pressure cylinder of a large steam turbine or air turbine, a heat shield is typically installed on the outer surface of the low-pressure cylinder to reduce the temperature of the inner and outer surfaces, thereby minimizing thermal stress and deformation. This shield is typically welded from 3-5 mm thick steel plates and bolted to the outer surface of the cylinder. Its primary function is to prevent exhaust gas from directly cooling the outer surface of the cylinder, preventing heat loss from the outer surface and improving unit thermal efficiency. It also reduces the temperature difference between the inner and outer surfaces of the cylinder, thereby reducing thermal stress and deformation, thereby improving the cylinder's strength and extending its service life.

[0003] Because the heat shield operates in the low-pressure exhaust zone, where the airflow is highly unstable, it is subjected to alternating excitation forces. If the shield's natural frequency falls within the airflow's excitation frequency band, resonance will occur, causing existing shields to become welded, fall off, or otherwise damaged. Some insulation structures also feature thicker insulation layers secured with numerous bolts, wire, or glue. These structures are often non-removable, making them difficult to inspect and repair. Summary of the Invention

[0004] The present invention aims to solve the problem that the existing heat insulation cover has a thick insulation interlayer and is fixed with a large number of bolts and steel wires or glue. This insulation structure is often non-detachable and inconvenient for unit maintenance. Instead, a detachable heat insulation cover for a side-intake low-pressure inner cylinder is proposed.

[0005] The present invention provides a detachable heat shield for a side-intake low-pressure inner cylinder, comprising a heat shield upper left portion 16, a heat shield upper right portion 17, a heat shield lower right portion 18, an air intake cylinder 19, and a heat shield lower left portion 20.

[0006] The upper left portion 16 of the heat shield and the upper right portion 17 of the heat shield are connected by a plurality of No. 1 bolt assemblies to form the upper half of the heat shield. The lower left portion 20 of the heat shield and the lower right portion 18 of the heat shield are connected by a plurality of No. 2 bolt assemblies to form the lower half of the heat shield. An air intake 19 is provided at the bottom of the lower right portion 18 of the heat shield. The upper half of the heat shield and the upper half of the heat shield are fixedly connected by a plurality of bolts. The mechanical structure of the No. 1 bolt assembly is the same as that of the No. 2 bolt assembly.

[0007] Furthermore, the No. 1 bolt assembly includes a waist-shaped slot angle steel 3, an L-shaped slot angle steel 4, a bolt 5, a nut 6 and a locking washer 7;

[0008] The bottom surface of the waist-shaped groove angle steel 3 is welded and fixed to the outer surface of the upper left portion 16 of the heat shield, and the bottom surface of the horizontal section of the L-shaped groove angle steel 4 is welded and fixed to the outer surface of the upper right portion 17 of the heat shield. The vertical section end surface of the L-shaped groove angle steel 4 is processed with a U-shaped hole, and the bottom end of the bolt 5 passes through the U-shaped holes on the waist-shaped groove angle steel 3 and the L-shaped groove angle steel 4 in sequence, and is threadedly connected with the nut 6. A locking washer 7 is provided between the bottom surface of the nut of the bolt 5 and the vertical section end surface of the waist-shaped groove angle steel 3;

[0009] Furthermore, the outer surfaces of the upper right portion 17 of the heat shield, the lower right portion 18 of the heat shield, and the air intake cylinder 19 are all processed with a plurality of rectangular grooves, and a U-shaped groove pad 8 is welded to the top of each rectangular groove. A hexagonal flange 9 is provided inside each rectangular groove, and a single-ear locking washer 10 is provided on the top surface of the hexagonal flange 9. The bottom of the countersunk bolt 11 passes through the single-ear locking washer 10, the hexagonal flange 9, and the U-shaped groove pad 8 in sequence, and is then threadedly connected to the mounting hole of the inner cylinder of the turbine.

[0010] Furthermore, a vertical plate 12 is provided on one side of the single-ear stop washer 10 on the top surface of the hexagonal flange 9;

[0011] Furthermore, a backing plate 2 is welded to both ends of the outer surface of the upper left portion 16 of the heat shield, the upper right portion 17 of the heat shield, the lower right portion 18 of the heat shield, and the lower left portion 20 of the heat shield, and a lifting ear 1 is provided at the top of each backing plate 2;

[0012] Furthermore, the lifting lug 1 is integrally provided with the backing plate 2;

[0013] Furthermore, a V-shaped rib plate 14 is provided on the upper half of the heat shield and inside the upper half of the heat shield, and an end plate 13 is provided on the bottom surface of the V-shaped rib plate 14;

[0014] Furthermore, a triangular rib 15 is welded between the end plate 13 and the inner wall of the heat shield.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention overcomes the shortcomings of the prior art. The heat insulation cover is welded with 6mm steel plates as a whole. According to the external contour of the low-pressure inner cylinder and the structural form of the upper and lower half dividing surfaces, the heat insulation cover also adopts an upper and lower half structure. In order to facilitate disassembly and assembly, it is divided into five parts in total. The parts are connected by bolts, which is convenient for disassembly and assembly and convenient for unit maintenance. The main function of the heat insulation cover is to prevent the exhaust gas from directly contacting the outer surface of the low-pressure inner cylinder, cooling the outer wall of the inner cylinder, and reducing the temperature difference between the inner and outer surfaces of the inner cylinder; thereby reducing the thermal stress and deformation of the inner cylinder, thereby improving the strength performance of the inner cylinder and extending the service life. The heat insulation cover and the outer wall of the inner cylinder are connected by bolts all around to ensure that the heat insulation cover and the inner cylinder are firmly connected and avoid damage to the heat insulation cover due to unstable resonance of the airflow. An anti-loosening structure is designed at the bolt fixing point to ensure safe and reliable connection and ensure that the unit will not loosen during long-term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic three-dimensional structural diagram of a detachable heat shield for a side-intake low-pressure inner cylinder according to the present invention;

[0018] Figure 2 This is a main cross-sectional view of a lifting ear structure in a detachable heat shield for a side-intake low-pressure inner cylinder according to the present invention;

[0019] Figure 3 It is a structural schematic diagram of a No. 1 bolt assembly and a No. 2 bolt assembly in a detachable heat shield for a side-intake low-pressure inner cylinder according to the present invention;

[0020] Figure 4 It is a cross-sectional view of a connection structure between a detachable heat shield and a steam turbine inner cylinder for a side-intake low-pressure inner cylinder according to the present invention;

[0021] Figure 5 yes Figure 4 A view of the connection structure between a detachable heat shield and a steam turbine inner cylinder for a side-intake low-pressure inner cylinder according to the present invention;

[0022] Figure 6 This is a schematic diagram of the connection between the middle end plate and the V-shaped rib plate of a detachable heat shield for a side-intake low-pressure inner cylinder according to the present invention;

[0023] Figure 7 This is a schematic diagram of the installation of a triangular rib in a detachable heat shield for a side-intake low-pressure inner cylinder described in the present invention. DETAILED DESCRIPTION

[0024] Specific implementation method 1: Combination Figure 1This embodiment describes a detachable heat shield for a side-intake low-pressure inner cylinder, comprising a heat shield upper left portion 16, a heat shield upper right portion 17, a heat shield lower right portion 18, an air intake cylinder 19, and a heat shield lower left portion 20.

[0025] The upper left portion 16 of the heat shield and the upper right portion 17 of the heat shield are connected by a plurality of No. 1 bolt assemblies to form the upper half of the heat shield. The lower left portion 20 of the heat shield and the lower right portion 18 of the heat shield are connected by a plurality of No. 2 bolt assemblies to form the lower half of the heat shield. An air intake 19 is provided at the bottom of the lower right portion 18 of the heat shield. The upper half of the heat shield and the upper half of the heat shield are fixedly connected by a plurality of bolts. The mechanical structure of the No. 1 bolt assembly is the same as that of the No. 2 bolt assembly.

[0026] In this specific embodiment, the heat shield is welded from 6mm steel plates. According to the external contour of the low-pressure inner cylinder and the structural form of the upper and lower half mid-sections, the heat shield also adopts an upper and lower half structure. In order to facilitate disassembly and assembly, it is divided into five parts in total. The parts are connected by bolts, which makes disassembly and assembly easy and facilitates unit maintenance.

[0027] Specific implementation method 2: Combination Figure 1 and Figure 3 This embodiment is described as a further limitation of the heat shield described in the first embodiment. This embodiment is a detachable heat shield for a side-intake low-pressure inner cylinder. The first bolt assembly includes a waist-shaped groove angle steel 3, an L-shaped groove angle steel 4, a bolt 5, a nut 6, and a retaining washer 7.

[0028] The bottom surface of the waist-shaped groove angle steel 3 is welded and fixed to the outer surface of the upper left part 16 of the heat insulation cover, and the bottom surface of the horizontal section of the L-shaped groove angle steel 4 is welded and fixed to the outer surface of the upper right part 17 of the heat insulation cover, and the vertical section end face of the L-shaped groove angle steel 4 is processed with a U-shaped hole, and the bottom end of the bolt 5 passes through the U-shaped holes on the waist-shaped groove angle steel 3 and the L-shaped groove angle steel 4 in turn, and is threadedly connected with the nut 6, and a stop washer 7 is provided between the bottom surface of the nut of the bolt 5 and the vertical section end face of the waist-shaped groove angle steel 3.

[0029] Specific implementation method three: Combination Figure 1 、 Figure 4 and Figure 5The present embodiment is described. The present embodiment is a further limitation of the heat shield described in the first embodiment. The present embodiment describes a detachable heat shield for a side-intake low-pressure inner cylinder. The outer surfaces of the upper right portion 17 of the heat shield, the lower right portion 18 of the heat shield and the air intake cylinder 19 are all processed with multiple rectangular grooves, and a U-shaped groove pad 8 is welded on the top of each rectangular groove. A hexagonal head flange 9 is provided inside each rectangular groove, and a single-ear stop washer 10 is provided on the top surface of the hexagonal head flange 9. The bottom of the countersunk bolt 11 passes through the single-ear stop washer 10, the hexagonal head flange 9 and the U-shaped groove pad 8 in sequence, and is then threadedly connected to the mounting hole of the turbine inner cylinder.

[0030] Specific implementation method four: Combination Figure 1 、 Figure 4 and Figure 5 This embodiment is described as a further limitation of the heat shield described in the third embodiment. This embodiment describes a detachable heat shield for a side-intake low-pressure inner cylinder, and a vertical plate 12 is provided next to the single-ear retaining washer 10 on the top surface of the hexagonal head flange 9.

[0031] Specific implementation method five: Combination Figure 1 and Figure 2 This embodiment is described as a further limitation of the heat shield described in the first embodiment. This embodiment is a detachable heat shield for a side-intake low-pressure inner cylinder. A backing plate 2 is welded to both ends of the outer surface of the upper left portion 16, the upper right portion 17, the lower right portion 18, and the lower left portion 20 of the heat shield, and each backing plate 2 is provided with a lifting ear 1 at the top end.

[0032] In this specific embodiment, lifting ears are symmetrically provided on each part of the heat insulation cover, which facilitates lifting during installation and disassembly.

[0033] Specific implementation method six: combination Figure 1 and Figure 2 This embodiment is described as a further limitation of the heat shield described in the fifth embodiment. This embodiment describes a detachable heat shield for a side-intake low-pressure inner cylinder, in which the lifting lug 1 and the pad 2 are integrally provided.

[0034] Specific implementation method seven: combination Figure 1 and Figure 6 This embodiment is described as a further limitation of the heat shield described in the first embodiment. This embodiment is a detachable heat shield for a side-intake low-pressure inner cylinder. A V-shaped rib 14 is provided on the upper half of the heat shield and inside the upper half of the heat shield, respectively. An end plate 13 is provided on the bottom surface of the V-shaped rib 14.

[0035] In this embodiment, a V-shaped rib plate 14 is provided on the upper half of the heat shield and inside the upper half of the heat shield, and an end plate 13 is provided on the bottom surface of the V-shaped rib plate 14 to improve the overall strength and rigidity.

[0036] Specific implementation method eight: combination Figure 1 and Figure 7 This embodiment is described as a further limitation of the heat shield described in the seventh embodiment. This embodiment describes a detachable heat shield for a side-intake low-pressure inner cylinder, wherein a triangular rib 15 is welded between the end plate 13 and the inner wall of the heat shield.

Claims

1. A detachable heat shield for a side-intake low-pressure inner cylinder, characterized by: It includes a left upper portion of the heat shield (16), a right upper portion of the heat shield (17), a right lower portion of the heat shield (18), an air intake cylinder (19) and a left lower portion of the heat shield (20); The upper left portion (16) of the heat shield and the upper right portion (17) of the heat shield are connected by a plurality of No. 1 bolt assemblies to form the upper half of the heat shield. The lower left portion (20) of the heat shield and the lower right portion (18) of the heat shield are connected by a plurality of No. 2 bolt assemblies to form the lower half of the heat shield. An air intake cylinder (19) is provided at the bottom of the lower right portion (18) of the heat shield. The upper half of the heat shield and the upper half of the heat shield are fixedly connected by a plurality of bolts. The No. 1 bolt assembly and the No. 2 bolt assembly have the same mechanical structure.

2. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 1, characterized in that: The No. 1 bolt assembly comprises a waist-shaped slot angle steel (3), an L-shaped slot angle steel (4), a bolt (5), a nut (6) and a stop washer (7); The bottom surface of the waist-shaped groove angle steel (3) is welded and fixed to the outer surface of the upper left part (16) of the heat shield, the bottom surface of the horizontal section of the L-shaped groove angle steel (4) is welded and fixed to the outer surface of the upper right part (17) of the heat shield, and the vertical section end face of the L-shaped groove angle steel (4) is processed with a U-shaped hole, and the bottom end of the bolt (5) passes through the U-shaped holes on the waist-shaped groove angle steel (3) and the L-shaped groove angle steel (4) in turn, and is threadedly connected to the nut (6), and a stop washer (7) is provided between the bottom surface of the nut of the bolt (5) and the vertical section end face of the waist-shaped groove angle steel (3).

3. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 1, characterized in that: The outer surfaces of the upper right portion (17) of the heat shield, the lower right portion (18) of the heat shield and the air inlet cylinder (19) are all processed with a plurality of rectangular grooves, and a U-shaped groove pad (8) is welded on the top of each rectangular groove, and a hexagonal flange (9) is provided inside each rectangular groove, and a single-ear stop washer (10) is provided on the top surface of the hexagonal flange (9). The bottom of the countersunk bolt (11) passes through the single-ear stop washer (10), the hexagonal flange (9) and the U-shaped groove pad (8) in sequence, and is then threadedly connected to the mounting hole of the inner cylinder of the turbine.

4. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 3, characterized in that: A vertical plate (12) is provided on one side of the single-ear stop washer (10) on the top surface of the hexagonal flange (9).

5. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 1, characterized in that: A backing plate (2) is welded to both ends of the outer surfaces of the upper left portion (16), the upper right portion (17), the lower right portion (18) and the lower left portion (20) of the heat shield, and a lifting lug (1) is provided at the top end of each backing plate (2).

6. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 5, characterized in that: The lifting lug (1) and the pad (2) are integrally arranged.

7. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 1, characterized in that: A V-shaped rib plate (14) is provided on the upper half of the heat shield and inside the upper half of the heat shield, respectively, and an end plate (13) is provided on the bottom surface of the V-shaped rib plate (14).

8. The detachable heat shield for a side-intake low-pressure inner cylinder according to claim 7, characterized in that: A triangular rib plate (15) is welded between the end plate (13) and the inner wall of the heat shield.

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