Steam turbine high and medium pressure cylinder shaft seal body outer cylinder body spraying heat insulation material heat preservation structure

Abstract

The utility model discloses steam turbine high pressure cylinder and medium pressure cylinder shaft seal body outer cylinder body spraying heat insulation material heat preservation structure, including base layer, main heat insulation layer, transition layer, ceramic fiber suture line layer, anchor nail, heat reflection layer, ceramic fiber reinforced layer and protective surface layer. Base layer adopts nanometer silane interface agent to spray on the surface of cylinder body, and main heat insulation layer is nanocrystalline composite heat insulation material, and transition layer is composed of metal base layer, ceramic base layer and organic composite base layer, and the multiple suture lines of ceramic fiber suture line layer are orthogonal grid inlay in the surface of main heat insulation layer, and anchor nail top is equipped with barb structure and root installs elastic silicone rubber gasket, and heat reflection layer is the aluminum foil that etches nanometer level groove and is equipped with wave embossing, and ceramic fiber reinforced layer is sealedly installed paraffin, and protective surface layer adopts organic silicon modified acrylic resin material. The structure has solved the problems of easy cracking of heat insulation layer, easy breaking of heat preservation material, unreasonable shaft seal heat preservation and oil touch flammable etc, and has improved heat preservation performance, structural stability and safety.

Description

Technical Field

[0001] This utility model relates to the field of steam turbines, and in particular to a thermal insulation structure for the outer cylinder body of high and intermediate pressure cylinder shaft seals of steam turbines, which is coated with thermal insulation material. Background Technology

[0002] A type of ultra-supercritical, single-stage reheat, condensing steam turbine unit commonly used for power generation has a separate high- and intermediate-pressure cylinder structure. Currently, the outer cylinder of the high- and intermediate-pressure cylinder shaft seals uses the traditional method of insulation with aluminum silicate fiber felt and fiberglass cloth. In the existing technology, under the influence of gravity and vibration, the insulation layer of the outer cylinder of the high- and intermediate-pressure cylinder shaft seals is prone to peeling, delamination, and cracking, resulting in a decrease in insulation performance. After long-term operation of the steam turbine, the shaft seals inevitably wear, leading to steam leakage and extremely high temperatures at the shaft seals. Due to the negative pressure state inside the bearing housing, broken insulation material is easily sucked into the oil baffle. After high-temperature carbonization, it may cause dynamic and static friction, leading to unstable or increased shaft vibration. Inadequate insulation at the shaft seals causes heat and steam to accumulate at the oil baffle. When oil leakage occurs at the oil baffle, lubricating oil drips or splashes onto the insulation material or cylinder surface, which can easily cause a fire at high temperatures.

[0003] Therefore, it is necessary to propose a thermal insulation structure for the outer cylinder body of the high and intermediate pressure cylinder shaft seals of steam turbines by spraying thermal insulation material to solve the above problems. Utility Model Content

[0004] The purpose of this utility model is to provide a thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seal of a steam turbine, so as to solve the problems of easy cracking of the insulation layer, brittleness of the insulation material, unreasonable shaft seal insulation, and flammability of the insulation material when in contact with oil.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] The high and intermediate pressure cylinder shaft seal of a steam turbine is coated with thermal insulation material for the outer cylinder body. The structure includes a base layer sprayed onto the cylinder body surface. A main thermal insulation layer is located on the side of the base layer away from the cylinder body surface. A transition layer is tightly bonded between the base layer and the main thermal insulation layer. A ceramic fiber stitching layer is located on the transition layer near the main thermal insulation layer. Multiple anchors are welded to the cylinder body surface, with the other end of each anchor connected to the main thermal insulation layer. A heat-reflective layer is located on the outer surface of the main thermal insulation layer. A ceramic fiber reinforcement layer is located on the outer surface of the heat-reflective layer. A protective surface layer is located on the outer surface of the ceramic fiber reinforcement layer.

[0007] Preferably, the base layer is coated on the cylinder surface with a nano-silane interface agent.

[0008] Preferably, the main insulation layer is made of nanocrystalline composite insulation material.

[0009] Preferably, the transition layer is provided with a metal base layer, a ceramic base layer, and an organic composite base layer in sequence from the base layer to the main insulation layer. The metal base layer is made of aluminum-iron alloy composite material, the ceramic base layer is made of aluminum oxide ceramic particles, and the organic composite base layer is made of organic resin material.

[0010] Preferably, the ceramic fiber suture layer includes ceramic fiber sutures, with multiple strands of ceramic fiber sutures distributed in an orthogonal grid, and the ceramic fiber sutures are embedded in the surface of the main insulation layer.

[0011] Preferably, the top of the anchor is provided with a barb structure, the anchor is embedded in the main heat insulation layer through the barb structure, and an elastic silicone rubber gasket is installed at the root position of the anchor near the bottom.

[0012] Preferably, the heat reflective layer is made of aluminum foil material, the surface of which is etched with nanoscale grooves, and the surface of the aluminum foil of the heat reflective layer is provided with wave-shaped embossing.

[0013] Preferably, the ceramic fiber reinforced layer has multiple pieces of paraffin wax internally sealed.

[0014] Preferably, the protective surface layer is made of silicone-modified acrylic resin material.

[0015] The technical effects and advantages of this utility model are as follows:

[0016] 1. By forming a chemical anchor between the base layer and the cylinder body, the transition layer achieves a gradient matching of the coefficient of thermal expansion, reducing interface stress; the ceramic fiber stitch layer is embedded in the main insulation layer with an orthogonal grid to form a three-dimensional stitch network, which improves shear strength and effectively prevents the insulation layer from peeling, delamination, and cracking due to gravity and vibration.

[0017] 2. Nanocrystalline composite thermal insulation materials can achieve better thermal insulation effects than traditional structures; the paraffin phase change material inside the ceramic fiber reinforcement layer absorbs heat and melts when the temperature rises sharply, suppressing local temperature rise and preventing the thermal insulation material from carbonizing and cracking due to high temperature.

[0018] 3. The silicone-modified acrylic resin protective surface layer is oleophobic and hydrophobic, preventing lubricating oil from penetrating and adhering; when oil leaks from the oil baffle, the surface layer can isolate the oil from contact with the high-temperature cylinder insulation material, preventing oil dripping and causing a fire.

[0019] 4. The anchor barb structure and the stitching network provide double fixation to prevent the insulation material from breaking and falling off; the protective surface layer and the ceramic fiber reinforcement layer are tightly bonded to form a closed system, preventing debris from being sucked into the negative pressure area of ​​the bearing box and eliminating the risk of dynamic and static collisions caused by carbonization. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the thermal insulation structure of the high and intermediate pressure cylinder shaft seals of the steam turbine, which is coated with thermal insulation material.

[0021] Figure 2 This is a schematic diagram of the installation structure of the ceramic fiber suture.

[0022] Figure 3 This is a schematic diagram of the waveform embossing structure of this practical application.

[0023] Figure 4 This is a schematic cross-sectional view of the ceramic fiber reinforced layer structure of this utility model.

[0024] In the diagram: 1. Base layer; 2. Main insulation layer; 3. Transition layer; 4. Ceramic fiber stitching layer; 5. Anchor; 6. Heat reflective layer; 7. Ceramic fiber reinforcement layer; 8. Protective surface layer; 9. Wave-shaped embossing; 10. Paraffin wax. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] This utility model provides, for example Figures 1-4 The heat insulation structure of the high and medium pressure cylinder shaft seal of the steam turbine, shown, includes a base layer 1, which is sprayed on the cylinder surface. A main heat insulation layer 2 is provided on the side of the base layer 1 away from the cylinder surface. A transition layer 3 is tightly bonded between the base layer 1 and the main heat insulation layer 2. A ceramic fiber stitching layer 4 is provided on the side of the transition layer 3 near the main heat insulation layer 2. Multiple anchors 5 are welded to the cylinder surface. The other end of the anchors 5 is connected to the main heat insulation layer 2. A heat reflective layer 6 is provided on the outer surface of the main heat insulation layer 2. A ceramic fiber reinforcement layer 7 is provided on the outer surface of the heat reflective layer 6. A protective surface layer 8 is provided on the outer surface of the ceramic fiber reinforcement layer 7.

[0027] Furthermore, the base layer 1 is coated with a nano-silane interface agent on the cylinder surface;

[0028] Before spraying the nano-silane interface agent onto the cylinder surface, the cylinder surface is first derusted using sandblasting equipment to improve surface roughness and adhesion, and prevent the material from falling off.

[0029] Furthermore, the main insulation layer 2 is made of nanocrystalline composite insulation material;

[0030] Nanocrystalline composite thermal insulation materials possess a unique nanoscale crystalline structure that significantly hinders heat conduction paths and reduces heat transfer efficiency. With a thermal conductivity as low as ≤0.03 W / (m・K), they achieve superior insulation performance at the same thickness compared to traditional insulation materials. This effectively reduces heat loss from the outer cylinder body of the high- and intermediate-pressure cylinder shaft seals in steam turbines, keeping surface temperatures within a reasonable range and preventing energy waste and equipment malfunctions caused by heat loss.

[0031] Furthermore, the transition layer 3 is provided with a metal base layer, a ceramic base layer, and an organic composite base layer in sequence from the base layer 1 to the main insulation layer 2. The metal base layer is made of aluminum-iron alloy composite material, the ceramic base layer is made of aluminum oxide ceramic particles, and the organic composite base layer is made of organic resin material.

[0032] From the base layer 1 to the main insulation layer 2, the materials are aluminum-iron alloy composite material, aluminum oxide ceramic particle material, and organic resin material in sequence. The coefficient of thermal expansion changes gradually. The thermal expansion coefficient of aluminum-iron alloy composite material is similar to that of cylinder metal, while the thermal expansion coefficient of organic resin material is more matched with that of nanocrystalline composite insulation material of the main insulation layer 3. This gradient design can effectively reduce interfacial stress, avoid cracking and falling off of the insulation structure due to thermal expansion and contraction, and improve the stability and durability of the overall structure.

[0033] The metal base layer has good thermal conductivity, which can evenly distribute heat on the cylinder surface; the ceramic base layer has low thermal conductivity, which can effectively inhibit heat transfer; the organic composite base layer further reduces heat conduction. The three layers of materials form a gradient thermal resistance, which gradually attenuates the heat flow from the cylinder surface to the main insulation layer, avoids local overheating, and improves the thermal insulation effect of the insulation structure.

[0034] Furthermore, the ceramic fiber suture layer 4 includes ceramic fiber sutures, with multiple strands of ceramic fiber sutures distributed in an orthogonal grid, and the ceramic fiber sutures are embedded in the surface of the main heat insulation layer 2;

[0035] The installation of ceramic fiber suture layer 4 needs to be carried out simultaneously with the spraying process of the main insulation layer 2. The suture and the insulation material are tightly fitted by layered implantation and grid positioning.

[0036] Multi-strand ceramic fiber stitching is distributed in an orthogonal grid with a spacing of 50mm×50mm, penetrating the surface of the main insulation layer to form a "stitching network". This tightly binds loose insulation material particles or interlayer structures, transforming the main insulation layer from a "layered structure" to an "integrated mesh structure", improving shear strength and effectively preventing delamination and peeling caused by vibration or thermal stress.

[0037] Furthermore, the top of the anchor 5 is provided with a barb structure, and the anchor 5 is embedded in the main heat insulation layer 2 through the barb structure. An elastic silicone rubber gasket is installed at the root position of the anchor 5 near the bottom.

[0038] After the barbed structure is embedded in the main insulation layer 2, it forms a "mechanical lock" with the nanocrystalline composite insulation material, which enhances the anchoring force. When the main insulation layer deforms due to thermal expansion and contraction, the barbed structure can limit the displacement of the insulation layer through the multi-directional constraint force embedded in the material, thus preventing interlayer voids or detachment. The silicone rubber gasket is installed between the anchor root and the cylinder surface, which can effectively buffer the high-frequency vibration during the operation of the steam turbine.

[0039] Furthermore, the heat reflective layer 6 is made of aluminum foil material, and the surface of the aluminum foil is etched with nano-level grooves. The surface of the aluminum foil of the heat reflective layer 6 is provided with wave-shaped embossing 9.

[0040] The groove structure increases the surface roughness, which further weakens the heat radiation penetration ability through multiple reflections; the wave embossing transforms the aluminum foil from a planar structure to a three-dimensional wave shape, which improves the bending stiffness and can effectively resist the compressive stress generated by the thermal expansion of the main insulation layer 2, thus avoiding the aluminum foil from wrinkling or breaking.

[0041] The embossed structure allows the aluminum foil to self-adjust through wave-like elastic deformation within ±2mm of thermal expansion displacement, preventing interlayer cracking caused by rigid deformation.

[0042] Furthermore, the ceramic fiber reinforced layer 7 has multiple pieces of paraffin wax 10 installed inside for internal sealing;

[0043] Paraffin wax absorbs heat and melts at high temperatures, absorbing the instantaneous heat from sudden steam leakage or abnormal operating conditions of the shaft seal, thus suppressing a sudden rise in local temperature. When the temperature drops, the paraffin wax solidifies and releases heat, compensating for heat loss, reducing temperature fluctuations on the cylinder surface, and improving thermal stability.

[0044] Furthermore, the protective surface layer 8 is made of silicone-modified acrylic resin material;

[0045] When oil seepage occurs at the oil baffle, the protective surface layer 8 can prevent lubricating oil from penetrating into the internal structural layer, thus avoiding an increase in the thermal conductivity of the insulation material due to oil immersion.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A thermal insulation structure for the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine, characterized in that: The system includes a base layer (1), which is sprayed onto the cylinder surface. A main heat insulation layer (2) is provided on the side of the base layer (1) away from the cylinder surface. A transition layer (3) is tightly bonded between the base layer (1) and the main heat insulation layer (2). A ceramic fiber stitch layer (4) is provided on the side of the transition layer (3) near the main heat insulation layer (2). Multiple anchors (5) are welded to the cylinder surface. The other end of the anchors (5) is connected to the main heat insulation layer (2). A heat reflection layer (6) is provided on the outer surface of the main heat insulation layer (2). A ceramic fiber reinforcement layer (7) is provided on the outer surface of the heat reflection layer (6). A protective surface layer (8) is provided on the outer surface of the ceramic fiber reinforcement layer (7).

2. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The base layer (1) is coated on the cylinder surface with a nano-silane interface agent.

3. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The main insulation layer (2) is made of nanocrystalline composite insulation material.

4. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The transition layer (3) is provided with a metal base layer, a ceramic base layer and an organic composite base layer in sequence from the base layer (1) to the main insulation layer (2). The metal base layer is made of aluminum-iron alloy composite material, the ceramic base layer is made of aluminum oxide ceramic particles, and the organic composite base layer is made of organic resin material.

5. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The ceramic fiber suture layer (4) includes ceramic fiber sutures, with multiple strands of ceramic fiber sutures distributed in an orthogonal grid, and the ceramic fiber sutures are embedded in the surface of the main heat insulation layer (2).

6. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The top of the anchor (5) is provided with a barb structure, and the anchor (5) is embedded in the main heat insulation layer (2) through the barb structure. An elastic silicone rubber gasket is installed at the root position of the anchor (5) near the bottom.

7. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The heat reflective layer (6) is made of aluminum foil material, and the surface of the aluminum foil is etched with nano-level grooves. The surface of the aluminum foil of the heat reflective layer (6) is provided with wave-shaped embossing (9).

8. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The ceramic fiber reinforced layer (7) is internally sealed with multiple pieces of paraffin wax (10).

9. The thermal insulation structure for spraying thermal insulation material onto the outer cylinder body of the high and intermediate pressure cylinder shaft seals of a steam turbine according to claim 1, characterized in that: The protective surface layer (8) is made of silicone-modified acrylic resin material.

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