Peephole plug, air cylinder plugging structure and use method of peephole plug and air cylinder plugging structure

Abstract

The invention discloses a peephole plug, an air cylinder plugging structure and a using method thereof, and belongs to the technical field of structural design of gas turbines. The structure comprises a cylinder, a blade ring, a guide pipe, an outer plug, an inner plug, an upper magnet and a lower magnet, the guide pipe is arranged outside a peephole in the outer wall of the cylinder, and the height of the guide pipe is larger than the thickness of a thermal insulation layer. The blade ring is provided with a taper hole and a through hole, the spherical surface of the inner plug makes contact with the taper hole, the cylindrical boss is matched with the through hole, an upper magnet and a lower magnet are embedded in the outer plug and the inner plug respectively, the magnetic poles of the upper magnet and the lower magnet are the same, and homopolar repulsive force is utilized to enable the inner plug to press the blade ring to achieve sealing. During maintenance, the heat preservation layer does not need to be dismantled, the outer plug is lifted through threads, the inner plug is taken out through magnetic adsorption, and convenience is remarkably improved. The problems of thermal stress seizure, tedious disassembly and assembly of a heat preservation layer and the like of traditional rigid plugging are solved, reliable sealing and convenient overhauling under high temperature and high pressure are achieved, the overhauling efficiency is greatly improved, the maintenance cost is reduced, and the sealing device is suitable for sealing the peephole of the double-layer cylinder structure of the gas turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbine structural design, and particularly to a peephole plug and a cylinder sealing structure for a double-layer cylinder and a blade ring of a gas turbine, which are applicable to reliable sealing and convenient maintenance in a high-temperature and high-pressure environment. Background Art

[0002] As an efficient and clean power equipment, gas turbines are widely used in the fields of energy, aviation, etc. Endoscopic inspection is an indispensable technical means in its maintenance process, which can evaluate the status of key components such as compressors, turbines, and burners without opening the cylinder, providing a basis for the operation and maintenance of the unit. Since the compressors and turbines of gas turbines mostly adopt a double-layer cylinder structure, the endoscope needs to pass through the peepholes of the outer cylinder and the internal blade ring, so special requirements are put forward for the peephole sealing structure:

[0003] Problem of expansion difference of double-layer cylinders: During operation, different deformations and expansion amounts are generated between the outer cylinder and the internal blade ring due to the temperature gradient. Traditional rigid sealing structures (such as direct bolt connection) cannot adapt to this difference, easily leading to seal failure or structural damage.

[0004] Requirement for high-temperature and high-pressure sealing: If the sealing of the peephole in the high-temperature and high-pressure area fails, air leakage may occur, which not only causes a decrease in efficiency but also poses safety risks. For example, the leakage of high-temperature gas may cause damage to surrounding components or fire hazards.

[0005] Defects of existing sealing structures:

[0006] The peepholes of the outer cylinder generally adopt a rigid connection method of "sealing plate + screw", and the screws are directly screwed into the cylinder body. During long-term operation, the thermal stress causes the screws to seize with the cylinder threads, making disassembly difficult;

[0007] The outer surface of the cylinder is covered with a heat-insulating layer. During maintenance, the heat-insulating layer needs to be removed first, increasing the workload and prolonging the shutdown time;

[0008] Traditional structures rely on mechanical pressing force for sealing, requiring high installation accuracy, and unable to dynamically compensate for the relative displacement of the double-layer cylinder. The sealing reliability decreases with the operation time.

[0009] Maintenance efficiency and maintenance cost: The disassembly complexity of the existing structure leads to low maintenance efficiency. Frequent screw replacement and disassembly and assembly of the heat-insulating layer increase the maintenance cost, especially in large units, this problem is more prominent.

[0010] In view of the above deficiencies, there is an urgent need for a peephole sealing structure that can adapt to the expansion difference of the double-layer cylinder, is resistant to high temperature and high pressure, is easy to disassemble and assemble, and is not affected by the heat-insulating layer, so as to improve the maintenance convenience and operation reliability of gas turbines. Summary of the Invention

[0011] The present invention aims to overcome the above-mentioned disadvantages of the prior art and provides an installation structure of a carbon ring seal and a method for disassembly, assembly and replacement thereof.

[0012] The technical solution adopted by the present invention is as follows:

[0013] A peephole plug and a cylinder sealing structure, comprising:

[0014] A peephole penetrating through the outer wall of the cylinder, with a guide tube arranged outside the peephole;

[0015] A blade ring, arranged inside the cylinder, and the blade ring is provided with a tapered hole and a through hole corresponding to the position of the peephole;

[0016] An outer plug, with a T-shaped longitudinal section, inserted into the guide tube, having an annular boss and an internal thread at the top, and a groove at the bottom;

[0017] An inner plug, having a groove at the top, a spherical surface in the middle and lower part, and a cylindrical boss at the bottom, the spherical surface contacts the tapered hole of the blade ring, and the cylindrical boss is in small clearance fit with the through hole;

[0018] An upper magnet, installed in the groove of the outer plug;

[0019] A lower magnet, installed in the groove of the inner plug, and the upper magnet and the lower magnet have the same magnetic poles and repel each other in the installed state.

[0020] Further, it includes a compression plug provided with an external thread, and the top of the guide tube is provided with a matching internal thread. The compression plug is a tapered plug or a fine-pitch cylindrical plug, and has a flat-head, cross-head or hexagon socket countersunk hole at the top.

[0021] Further, a stud matching the internal thread of the outer plug is also provided at the bottom of the compression plug.

[0022] Further, a heat-insulating layer is provided on the outer wall of the cylinder, and the height of the guide tube is greater than the thickness of the heat-insulating layer.

[0023] Further, the guide tube is provided with a platform matching the T-shaped outer plug, and a sealing gasket is provided on the platform.

[0024] Further, the cross-sectional diameter of the upper magnet is greater than that of the lower magnet, and their projections in the height direction coincide.

[0025] Further, the upper magnet is connected to the outer plug by inlaying, pasting or clearance fit, and the lower magnet is connected to the inner plug by inlaying, pasting or clearance fit.

[0026] Further, a method for using a peephole plug and a cylinder sealing structure includes the following steps:

[0027] S1: Insert the inner plug into the blade ring to make the spherical surface contact the tapered hole;

[0028] S2: Install the sealing gasket on the platform of the guide pipe, insert the outer plug, and keep a gap between the upper magnet and the lower magnet with opposite magnetic poles.

[0029] S3: Tighten the compression plug, push and fix the outer plug through the compression plug, and press the inner plug against the blade ring by the repulsive force between the upper magnet and the lower magnet.

[0030] Furthermore, the removal steps are as follows: Remove the compression plug, screw the screw rod into the inner thread at the top of the outer plug, and take out the outer plug; Use a magnetic metal rod with a flat bottom and a diameter equivalent to that of the inner plug, insert it into the guide pipe, and take out the inner plug by magnetic adsorption.

[0031] Furthermore, after removing the outer plug and the inner plug, insert the endoscope into the internal flow path of the unit through the through hole of the blade ring to check the blades or the flow path surface of the blade ring.

[0032] After the inspection, use the installation method in steps S1 - S3 to reset the plugging structure.

[0033] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0034] Through the dynamic compensation of magnetic repulsive force and the optimized design of the structure, the present invention significantly improves the reliability and maintenance efficiency of the peephole plugging of gas turbines.

[0035] In terms of sealing performance, the line contact fit between the spherical surface of the inner plug and the conical hole of the blade ring, combined with the axial pressing force generated by the repulsive force of the same poles of the upper and lower magnets, can automatically adapt to the radial and axial expansion and deformation of the cylinder and the blade ring due to temperature differences, avoiding the sealing failure or structural damage caused by thermal stress concentration in traditional rigid plugging, and ensuring long-term reliable sealing under high-temperature and high-pressure environments.

[0036] In terms of maintenance convenience, the height of the guide pipe is greater than the thickness of the thermal insulation layer, moving the operation interface outside the thermal insulation layer, completely eliminating the process of removing the thermal insulation layer. The single-hole maintenance time is shortened from several hours of the traditional structure to within 10 minutes. The outer plug is quickly fixed through the compression plug, and the inner and outer plugs are disassembled without jamming by using thread lifting and magnetic adsorption respectively. Combined with the lightweight hollow structure design, the operation difficulty and labor intensity are significantly reduced.

[0037] In terms of maintenance cost and lifespan, the magnet connection replaces the screw rigid connection, eliminating the problem of thread jamming and reducing the replacement frequency of vulnerable parts; the combined design of the sealing gasket and spherical seal improves the anti-vibration and anti-impact capabilities, extending the service life of the structural components. In addition, the magnet material selects a permanent magnet with a Curie temperature much higher than the operating temperature to ensure stable magnetism during long-term operation without additional maintenance. The overall structure takes into account sealing, adaptability, and convenience, providing an innovative solution for the efficient maintenance of gas turbines, and is expected to reduce the maintenance cost by more than 30% and improve the availability of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0039] Figure 2 is a schematic diagram of the structure of the blade ring peephole of the present invention;

[0040] Figure 3 is a schematic diagram of the structure of the guide pipe of the present invention;

[0041] Figure 4 is a schematic diagram of the structure of the outer plug of the present invention;

[0042] Figure 5 is a schematic diagram of the structure of the inner plug of the present invention

[0043] Figure 6 is a schematic diagram of the deformation of the outer plug of the present invention;

[0044] Figure 7 is a schematic diagram of the deformation of the inner plug of the present invention.

[0045] Reference numerals in the drawings:

[0046] 1 - cylinder, 2 - blade ring, 21 - tapered hole, 22 - through hole, 3 - compression plug, 4 - sealing gasket, 5 - guide pipe, 51 - top of the guide pipe, 52 - platform, 6 - outer plug, 61 - annular boss, 62 - internal thread, 63 - groove, 7 - inner plug, 71 - groove, 72 - spherical surface, 73 - cylindrical boss, 8 - upper magnet, 9 - lower magnet

[0047] SPECIFIC EXAMPLE

[0048] The present invention will be described in detail below with reference to the drawings.

[0049] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Example 1

[0051] In this embodiment, asFigure 1 As shown in the figure, a peephole plug and a cylinder sealing structure include:

[0052] A peephole penetrating through the outer wall of the cylinder, with a guiding tube arranged outside the peephole;

[0053] A vane ring, arranged inside the cylinder, and the vane ring is provided with a conical hole and a through hole corresponding to the position of the peephole;

[0054] An outer plug, with a T-shaped longitudinal section, inserted into the guiding tube, having an annular boss and an internal thread at the top, and a groove at the bottom;

[0055] An inner plug, having a groove at the top, a spherical surface in the middle and lower part, and a cylindrical boss at the bottom. The spherical surface contacts the conical hole of the vane ring, and the cylindrical boss is in small clearance fit with the through hole;

[0056] An upper magnet, installed in the groove of the outer plug;

[0057] A lower magnet, installed in the groove of the inner plug, and the upper magnet and the lower magnet have the same magnetic poles, and the two repel each other in the installed state.

[0058] Specifically: Cylinder: A peephole is penetrated through the outer wall, and a guiding tube is coaxially welded and fixed outside the peephole. The guiding tube is a hollow circular tube structure, and its axis coincides with the axis of the peephole.

[0059] Vane ring: Located inside the cylinder, a conical hole (the conical surface angle matches the spherical surface of the inner plug) and a through hole are machined circumferentially corresponding to the position of the peephole. The through hole is coaxial with the conical hole, and the diameter of the through hole is slightly larger than the outer diameter of the cylindrical boss, forming a small clearance fit of 0.05 - 0.1 mm.

[0060] Outer plug: The longitudinal section is T-shaped, composed of an upper disk and a lower cylinder (with a clearance fit with the inner diameter of the guiding tube). An annular groove is opened at the bottom of the cylinder, and the groove depth is the same as the height of the upper magnet. The upper magnet is embedded in the groove through clearance fit, forming a rigid connection with the outer plug.

[0061] Inner plug: A groove is opened at the top for installing the lower magnet, a spherical surface is machined in the middle and lower part, and the curvature radius of the spherical surface is the same as the curvature of the conical hole of the vane ring to ensure line contact sealing; The cylindrical boss at the bottom is inserted into the through hole of the vane ring, and the length of the boss is greater than the depth of the through hole to prevent tilting.

[0062] Magnet arrangement: Both the upper magnet and the lower magnet are cylindrical, and the magnetic pole directions are the same along the axis. After installation, the axes of the two magnets coincide, and a gap of 3 - 5 mm is maintained, using the repulsive force of the same poles to generate an axial pressing force.

[0063] Sealing principle: The spherical surface of the inner plug contacts the conical hole of the blade ring to form an initial sealing surface. The repulsive force between the upper magnet and the lower magnet is transmitted through the outer plug and the guiding tube, pressing the inner plug tightly against the blade ring to compensate for the expansion difference between the double-layer cylinder. Even if there is an axial or radial relative displacement between the cylinder and the blade ring, the magnetic repulsive force always maintains the contact pressure between the inner plug and the blade ring, preventing air leakage.

[0064] The guiding tube moves the installation position of the outer plug to the outside of the thermal insulation layer, so there is no need to remove the thermal insulation layer during maintenance; the magnetic repulsive force is a non-rigid connection method, allowing a certain degree of relative movement, which solves the problem of screw jamming caused by inconsistent thermal expansion in traditional rigid plugging.

[0065] Furthermore, it includes a compression plug with an external thread. The top of the guiding tube is provided with an internal thread that matches it. The compression plug is a tapered plug or a fine-threaded cylindrical plug, and a flat head, cross head, or hex socket countersunk hole is provided at the top.

[0066] Guiding tube: The inner wall of the top is machined with an internal thread (tapered thread or fine-threaded straight thread can be selected), and the thread length is not less than the thread section length of the compression plug.

[0067] Compression plug: A tapered plug or a fine-threaded cylindrical plug is used. A countersunk hole (such as a hex socket) is opened at the top of the plug, and the depth of the countersunk hole is adapted to a special tool (such as a hex key); the bottom surface of the plug contacts the annular boss at the top of the outer plug to form an axial positioning surface.

[0068] Connection and sealing: When tightening the compression plug, the plug moves downward through thread rotation, pushing the outer plug to compress the sealing gasket, and at the same time squeezing the upper magnet downward, increasing the repulsive force on the lower magnet to ensure the stability of the pressure on the sealing surface of the inner plug.

[0069] The countersunk hole design facilitates the quick disassembly and assembly using standard tools. The fine-threaded or tapered thread increases the sealing performance and anti-loosening performance of the connection, avoiding the loosening problem caused by vibration of traditional coarse-threaded screws.

[0070] Furthermore, a stud that matches the internal thread of the outer plug is also provided at the bottom of the compression plug.

[0071] Compression plug: A stud extends from the center position at the bottom. The outer diameter of the stud matches the internal thread at the top of the outer plug, and the length of the stud is slightly less than the depth of the internal thread of the outer plug.

[0072] Outer plug: An internal thread is opened at the center of the annular boss at the top, forming a threaded connection with the stud at the bottom of the compression plug.

[0073] Double fixation: The compression plug not only presses the outer plug through the end face, but also the stud at its bottom meshes with the internal thread of the outer plug, forming a "thread + end face" double fixation structure. During the operation of the unit, vibration and thermal stress are dispersed through the stud and the thread, avoiding the circumferential rotation or axial movement of the outer plug caused by single-end face contact.

[0074] Anti-loosening mechanism: The fit between the stud and the internal thread increases the shear resistance of the connection, especially suitable for high-temperature and high-frequency vibration environments. Compared with the traditional structure that only relies on end-face pressing, the risk of loosening of the external plug is significantly reduced.

[0075] Furthermore, a heat-insulating layer is provided on the outer wall of the cylinder, and the height of the guide pipe is greater than the thickness of the heat-insulating layer.

[0076] Cylinder: The outer wall is covered with a heat-insulating layer with a thickness of D; the height H of the guide pipe (5) is designed as D + 20 mm to ensure that the top of the guide pipe is completely exposed outside the heat-insulating layer and an operating space is reserved.

[0077] Detachable heat-insulating layer: During maintenance, the operator can directly contact the compression plug and the external plug at the top of the guide pipe outside the heat-insulating layer without removing the heat-insulating layer. In the traditional structure, the heat-insulating layer needs to be peeled off first for operation. This design moves the operation interface outward, saving the time for disassembling and assembling the heat-insulating layer, and at the same time avoiding damage to the heat-insulating layer and degradation of the heat-insulating performance caused by repeated disassembly.

[0078] The height of the guide pipe keeps the top thread away from the high-temperature surface of the cylinder, reducing the influence of thermal stress on the thread and lowering the probability of screw seizure.

[0079] Furthermore, the guide pipe is provided with a platform matching the T-shaped external plug, and a sealing gasket is provided on the platform.

[0080] Guide pipe: An annular platform is machined in the middle of the inner wall, and the width of the platform matches the outer diameter of the sealing gasket; the sealing gasket can be a metal wound gasket (high-temperature area) or a flexible graphite gasket (medium-temperature area), with a gasket thickness of 0.5 - 2 mm, and is embedded in the platform groove during installation.

[0081] External plug: The horizontal shoulder of the T-shaped structure contacts the platform, and when compressed, the shoulder squeezes the sealing gasket to form a radial seal.

[0082] Sealing mechanism: After the external plug is inserted into the guide pipe, the compression plug pushes the external plug downward, so that the shoulder of the external plug generates an axial pressure on the sealing gasket, and the gasket undergoes elastic deformation to fill the gap, preventing gas from leaking from the mating surface between the guide pipe and the external plug.

[0083] Flexible or rigid gaskets are selected according to different temperature regions. Metal gaskets are suitable for high-temperature regions above 600°C, and non-metal gaskets are suitable for low-temperature regions, ensuring sealing reliability under all working conditions. Compared with single-material sealing, the application range is wider.

[0084] Furthermore, the cross-sectional diameter of the upper magnet is greater than the cross-sectional diameter of the lower magnet, and their projections in the height direction coincide.

[0085] Upper magnet: The cross-sectional diameter is D1, and the cross-sectional diameter of the lower magnet is D2. It is designed that D1 > D2, and D1 - D2 = 2 - 5 mm; the axial projections of the two magnets completely coincide (i.e., the edge of the upper magnet covers the edge of the lower magnet).

[0086] Expansion compensation: When there is an axial expansion difference between the cylinder and the blade ring (such as the expansion amount of the cylinder is less than that of the blade ring), the inner plug moves downward with the blade ring, and the axial distance between the upper magnet and the lower magnet increases. However, due to the larger diameter of the upper magnet, their projections in the height direction always coincide, ensuring that the action line of the magnetic repulsion force does not shift.

[0087] Stable sealing: The coincident projection avoids the attenuation of the repulsive force caused by the edge effect of the magnet. Even when the relative displacement of the double-layer cylinder reaches 1 - 3 mm, the repulsive force still remains above 90% of the design value, maintaining the stable pressing of the inner plug on the blade ring and preventing the sealing failure caused by the magnetic circuit shift.

[0088] Furthermore, the upper magnet is connected to the outer plug by inlaying, pasting or clearance fit, and the lower magnet is connected to the inner plug by inlaying, pasting or clearance fit.

[0089] Upper magnet and outer plug: Adopt clearance fit (clearance amount 0.02 - 0.05 mm). A circular groove is machined on the outer side of the magnet, and a convex rib is provided on the inner wall of the groove of the outer plug. The convex rib is embedded into the magnet groove to form a mechanical lock; or it is pasted through a high-temperature resistant adhesive (such as ceramic glue), and the thickness of the glue layer is 0.1 mm to ensure that it does not fall off under long-term high temperature.

[0090] Lower magnet and inner plug: Adopt the inlaying method. A positioning pin is provided at the bottom of the groove of the inner plug, and a corresponding pin hole is provided on the bottom surface of the magnet. After insertion, it is fixed by a pin, or it is directly pressed in by using a small clearance fit.

[0091] Reliable fixation: The combination of mechanical connection (clearance, inlay) and gluing ensures that the magnet does not loosen under high temperature (500 - 700 °C) and vibration environments. The traditional single gluing method may fail due to high temperature, and the composite fixation method of this design reduces the risk of magnet detachment.

[0092] Integrated design: The magnet and the plug move as a whole, avoiding the pole shift caused by the independent displacement of the magnet, ensuring that the direction of the repulsive force is always along the axis, and maintaining the stability of the sealing structure.

[0093] Embodiment 2

[0094] A method for using a peephole plug and a cylinder sealing structure includes the following steps:

[0095] S1: Positioning of the inner plug

[0096] Vertically align the inner plug with the tapered hole of the blade ring and slowly insert it until the spherical surface completely fits the tapered hole. The cylindrical boss enters the through hole, and the small clearance between the boss and the through hole allows slight radial movement while restricting the tilting of the inner plug.

[0097] S2: External plug pre-installed

[0098] Place a sealing gasket on the guide tube platform and insert the outer plug into the guide tube, ensuring that the upper magnet and the lower magnet are aligned in the axis and that a gap of 3-5 mm is maintained (controlled by the insertion depth of the outer plug).

[0099] S3: Press and fix

[0100] Use a special tool (such as an Allen wrench) to tighten the compression screw plug. The screw plug moves downward to push the outer plug. While compressing the sealing gasket, the upper magnet approaches the lower magnet, the same-pole repulsion increases, and the inner plug is tightly pressed against the cone hole of the blade ring (contact stress ≥ 50MPa).

[0101] Step-by-step sealing: Initial sealing is first achieved through mechanical positioning (spherical surface + boss), and then dynamic compensation is achieved through magnetic repulsion. This ensures that even if there are slight processing errors during installation, the position of the inner plug can be automatically adjusted through magnetic repulsion to form a reliable seal.

[0102] No rigid contact: The inner plug and the outer plug are not in direct contact, and the pressure is transmitted only through magnetic repulsion, which avoids the stress concentration caused by expansion difference in traditional rigid connection and improves the life of the structure.

[0103] Further, the removal steps are as follows: remove the external plug

[0104] Screw a screw into the internal thread at the top of the external plug, pull the external plug upward through the screw, and use the shoulder of the T-shaped structure to cooperate with the inner wall of the guide tube to remove it smoothly (to avoid tilting and jamming).

[0105] Adsorption internal plug

[0106] Use a magnetic metal rod with a flat bottom (such as an iron rod) to insert it into the guide tube. The metal rod is adsorbed by the lower magnet (magnetic force ≥ 50N). Pull out the inner plug vertically upwards to separate the spherical surface from the tapered hole, and the disassembly is completed.

[0107] Magnetic adsorption is used instead of traditional mechanical grabbing to avoid damage to the surface of the inner plug; the internal thread design of the outer plug provides a reliable fulcrum, and compared with the traditional hooking method, the disassembly efficiency is increased by more than 50%.

[0108] The inner wall of the guide tube is smooth, and the T-shoulder of the external plug is precisely matched with the inner diameter of the guide tube to reduce friction. Even after long-term operation, the disassembly torque remains within 1.2 times the initial value, solving the problem of difficult disassembly caused by traditional screws biting.

[0109] Further, after removing the internal and external plugs, insert the endoscope probe into the unit flow path through the through-hole of the blade ring. The probe can rotate 360°, take high-definition images of the stator blades and the blade ring flow path surface, and transmit the images to an external display in real time to detect defects such as cracks and wear.

[0110] Reset the plug

[0111] After the inspection is completed, operate in reverse according to the installation steps S1 - S3: first insert the internal plug, install the sealing gasket and the external plug, and tighten the compression plug to ensure that the magnetic repulsive force is re-established, the spherical surface of the internal plug fits tightly with the tapered hole, and the sealing state is restored.

[0112] During the entire inspection process, there is no need to disassemble the insulation layer and complex mechanical components. The single-hole maintenance time is shortened, and the maintenance efficiency of the unit is greatly improved.

[0113] Reversible design: After resetting, the magnetic repulsive force and the mechanical seal structure return to the initial state, and the sealing performance is the same as when newly installed, ensuring that the structural reliability does not decrease after multiple inspections and reducing the long-term maintenance cost.

[0114] For ease of installation, the external plug and the internal plug can be designed to be lightweight, including but not limited to using a hollow structure or reducing the diameter at the straight section, such as Figure 6 and Figure 7 shown.

[0115] Through the triple innovation of "mechanical positioning + magnetic repulsive force compensation + external operation interface", the present invention solves the contradictions of double-layer cylinder expansion difference, high-temperature sealing, and maintenance convenience.

[0116] Mechanical positioning: The line contact between the spherical surface of the internal plug and the tapered hole of the blade ring provides an initial sealing surface; the clearance fit between the cylindrical boss and the through-hole restricts roll and guides axial movement.

[0117] Magnetic repulsive force compensation: The repulsive force of like-pole magnets forms a dynamic compression force, automatically adapting to the relative displacement between the cylinder and the blade ring, avoiding stress concentration in rigid connections, and achieving "gapless sealing".

[0118] External operation interface: The guide tube moves the plugging structure outside the insulation layer. The operation does not require damaging the insulation layer. The thread and magnetic design simplify the disassembly and assembly process, fundamentally solving the pain points of the traditional structure.

[0119] Through material selection (such as high Curie temperature magnets), structural optimization (such as T-shaped external plugs, stepped through-holes), and mechanical design (such as clearance fit, contact stress), each component forms a complete solution for plugging the peephole under high-temperature and high-pressure environments, combining reliability, convenience, and economy.

[0120] The above are only the preferred embodiments of the invention, and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A peephole plug and a cylinder sealing structure, characterized in that: Comprising: A viewing hole penetrating and provided on the outer wall of the cylinder (1), with a guiding tube (5) provided outside the viewing hole; a blade ring (2) provided inside the cylinder (1), and a conical hole (21) and a through hole (22) corresponding to the position of the viewing hole are provided on the blade ring (2). An outer plug (6) with a T-shaped longitudinal section, inserted into the guiding tube (5), having an annular boss (61) and an internal thread (62) at the top, and a groove (63) at the bottom. An inner plug (7) with a groove (71) at the top, a spherical surface (72) in the middle and lower part, and a cylindrical boss (73) at the bottom. The spherical surface (72) contacts the conical hole (21) of the blade ring (2), and the cylindrical boss (73) is in small clearance fit with the through hole (22). An upper magnet (8) installed in the groove (63) of the outer plug (6). A lower magnet (9) installed in the groove (71) of the inner plug (7), and the upper magnet (8) and the lower magnet (9) have the same magnetic poles and repel each other in the installed state.

2. The peephole plug and cylinder sealing structure according to claim 1, characterized in that: Comprising a compression plug (3) provided with an external thread, and the top (51) of the guiding tube is provided with a matching internal thread. The compression plug (3) is a conical plug or a fine-thread cylindrical plug, and has a flat, cross-shaped or hexagon socket head at the top.

3. The peephole plug and cylinder sealing structure according to claim 2, characterized in that: A stud matching the internal thread (62) of the outer plug (6) is further provided at the bottom of the compression plug (3).

4. A peephole plug and a cylinder sealing structure according to claim 1, characterized in that: A heat insulation layer is provided on the outer wall of the cylinder (1), and the height of the guiding tube (5) is greater than the thickness of the heat insulation layer.

5. The peephole plug and cylinder sealing structure according to claim 1, wherein: The guiding tube (5) is provided with a platform (52) matching the T-shaped outer plug (6), and a sealing gasket (4) is provided on the platform (52).

6. The peephole plug and cylinder sealing structure according to claim 1, characterized in that: The cross-sectional diameter of the upper magnet (8) is greater than the cross-sectional diameter of the lower magnet (9), and their projections in the height direction coincide.

7. A peephole plug and a cylinder sealing structure according to claim 1, characterized in that: The upper magnet (8) is connected to the outer plug (6) by inlaying, pasting or clearance fit, and the lower magnet (9) is connected to the inner plug (7) by inlaying, pasting or clearance fit.

8. A method of using a peephole plug and a cylinder sealing structure, which is applied to the peephole plug and the cylinder sealing structure according to any one of claims 1-7, and is characterized in that: Comprising the following steps: S1: Insert the inner plug (7) into the blade ring (2) so that the spherical surface (72) contacts the conical hole (21). S2: Install the sealing gasket (4) on the platform (52) of the guiding tube (5), insert the outer plug (6) so that the upper magnet (8) and the lower magnet (9) maintain a gap and have opposite magnetic poles. S3: Tighten the compression plug (3), push and fix the outer plug (6) through the compression plug (3), and press the inner plug (7) against the blade ring (2) by the repulsive force between the upper magnet (8) and the lower magnet (9).

9. The method of using a peephole plug and a cylinder sealing structure according to claim 8, characterized in that: The removal steps are as follows: Remove the compression plug (3), screw a screw rod into the internal thread (62) at the top of the outer plug (6), and take out the outer plug (6); use a magnetic metal rod with a flat bottom and a diameter equivalent to that of the inner plug (7), insert it into the guiding tube (5), and take out the inner plug (7) by magnetic adsorption.

10. The usage method of a peephole plug and a cylinder sealing structure according to claim 9, characterized in that: After removing the outer plug (6) and the inner plug (7), insert an endoscope into the internal flow passage of the unit through the through hole (22) of the blade ring (2) to check the blades or the blade ring flow passage surface. After the inspection, use the installation method of steps S1 - S3 to reset the sealing structure.

Images