A rotary sealing device suitable for high-temperature heat conducting oil equipment

Abstract

The application provides a rotary sealing device suitable for high-temperature heat conducting oil equipment, which comprises a rear end part, a middle part assembly and a front end part; the middle part assembly comprises a pipe ball with an annular flange; a ball ring is sleeved on the pipe ball and abuts against the right end surface of the annular flange of the pipe ball; a support ring, a positioning seat, a nickel-based high-temperature corrosion-resistant alloy spring and a column ring are sequentially abutted against the left end surface of the annular flange of the pipe ball and are sleeved on the pipe ball; the rear end part is sleeved outside the middle part assembly, and the rear end part comprises a shell, and the left end of the shell is fixedly connected with a rear end cover; the front end part is connected at the right end of the rear end part and is sleeved outside the middle part assembly, and the front end part comprises a front end cover abutting against the right end surface of the ball ring and a guide ring embedded in the front end cover and sleeved on the pipe ball; the guide ring is in clearance fit with the pipe ball, and the clearance fit state is maintained under the high-temperature 300 DEG C working condition. The application can improve the sealing reliability under the high-temperature working condition and avoid leakage.

Description

Technical Field

[0001] This invention relates to the field of rotary joint technology, and more specifically, to a rotary sealing device suitable for high-temperature heat transfer oil equipment. Background Technology

[0002] Many devices on the market currently require rotary joints that use high-temperature heat transfer oil for heating and insulation. The medium used is high-temperature heat transfer oil, and the maximum required temperature is between 280℃ and 300℃. However, the springs used in these rotary joints for high-temperature heat transfer oil are ordinary alloy or stainless steel springs, which lack sufficient temperature resistance. Under high-temperature heat transfer oil conditions, the spring force becomes unstable and decreases significantly, affecting the reliability of the rotary joint's seal. Simultaneously, the fit clearance between the outer diameter of the tube ball and the inner diameters of the cylindrical and guide rings is too small. Due to the difference in linear expansion coefficients between the tube ball material and graphite, the tube ball is prone to "jamming" at high temperatures, preventing it from rotating and causing seal failure. Therefore, rotary joints are prone to leakage under high-temperature conditions. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a rotary sealing device suitable for high-temperature heat transfer oil equipment, so as to overcome the defects in the prior art.

[0004] To achieve the above objectives, the present invention provides a rotary sealing device suitable for high-temperature heat transfer oil equipment, comprising a rear end, a middle assembly, and a front end; the rear end is sleeved outside the middle assembly, and the front end is sleeved outside the middle assembly and connected to the right end of the rear end; wherein, the middle assembly includes a tube ball with an annular flange; a ball ring sleeved on the tube ball abuts against the right end face of the annular flange of the tube ball, forming a tube ball sealing surface; a support ring sleeved on the tube ball abuts against the left end face of the annular flange of the tube ball to support the parallel tube ball; a positioning seat sleeved on the tube ball abuts against the left end face of the support ring; and a sleeved positioning seat abuts against the left end face of the positioning seat. A spring mounted on the tube ball is used for elastic force compensation; the spring is made of a nickel-based high-temperature and corrosion-resistant alloy to ensure elastic force stability at a high temperature of 300°C; the left end of the spring abuts against a cylindrical ring fitted on the tube ball to support the parallel tube ball; the rear end includes a housing and a rear end cover with a convex ring, the housing has a positioning end face, the convex ring of the rear end cover is engaged in the left end of the positioning end face of the housing, and a metal gasket for sealing the rear end cover is sandwiched between the housing and the rear end cover to form a rear end fitted outside the middle assembly; wherein, the positioning end face abuts against the left end face of the positioning seat of the middle assembly, and a second anti-rotation pin is inserted on the positioning seat. The left end of the second anti-rotation pin is embedded in the positioning end face of the housing to prevent rotation of the positioning seat; the rear end cover is sleeved on the outside of the column ring of the middle component and presses against the left end of the spring of the middle component; the rear end cover is embedded with a first anti-rotation pin, and the right end of the first anti-rotation pin is embedded in the left end face of the column ring to prevent rotation of the column ring; the front end includes a front end cover with a convex ring, and two first grooves are symmetrically provided on the right end face of the convex ring of the front end cover; a guide ring is embedded in the convex ring of the front end cover, and two second grooves are symmetrically provided on the right end face of the guide ring, the two second grooves corresponding to the two first grooves to form two combined grooves, each of the two combined grooves... A guide ring baffle is embedded, which is fixedly connected to the front end cover and presses against the guide ring to prevent rotation of the guide ring, forming a front end sleeved outside the middle component. The front end cover abuts against the right end face of the ball ring of the middle component to provide a seal and form an end cover sealing surface. The front end cover is fixedly connected to the right end of the rear housing, and a front end cover metal gasket for sealing is sandwiched between the housing and the front end cover. The contact surface between the guide ring and the tube ball of the middle component is clearance fit, and the clearance fit is maintained under high temperature conditions of 300°C to support the parallel tube ball and allow the tube ball to rotate and swing freely.

[0005] Through the above technical solution, the spring is made of nickel-based high-temperature and corrosion-resistant material with a maximum temperature of 500℃ to ensure that the spring force is stable at an oil temperature of 300℃, thereby ensuring the reliability and stability of the rotary joint seal. Due to the different materials of the tube ball and the guide ring, their coefficients of linear expansion are also different. Therefore, the gap between the contact surfaces of the tube ball and the guide ring must still be controlled within the clearance fit range under the high-temperature condition of 300℃, and cannot be within the transition fit or interference fit range. This ensures that the tube ball can rotate and swing freely at high temperatures without being stuck, thereby ensuring the reliability of the seal and solving the problem of leakage that is prone to occur under high-temperature conditions.

[0006] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the nickel-based high-temperature and corrosion-resistant alloy is Inconel 718.

[0007] Through the above technical solution, at an oil temperature of 300℃, Inconel718 has sufficient high-temperature mechanical stability and creep resistance, which can ensure the stable operation of the spring.

[0008] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the material of the end cap sealing surface and the tube ball sealing surface is 42CrMo.

[0009] Through the above technical solution, the material of the sealing surface on the end cap is replaced with heat-resistant steel 42CrMo (GB / T3077-2015 standard) instead of ordinary carbon steel 45#, which improves the hardness of the sealing surface, reduces the deformation of the sealing surface, and thus improves the wear resistance and sealing performance of the sealing surface.

[0010] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the end cap sealing surface and the tube ball sealing surface are subjected to quenching and tempering treatment so that the hardness of the sealing surface reaches 30-33 HRC.

[0011] Through the above technical solution, the sealing surface on the end cap has been heat-treated to further improve the hardness of the sealing surface and reduce the deformation of the sealing surface, thereby improving the wear resistance and sealing performance of the sealing surface.

[0012] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the end cap sealing surface and the tube ball sealing surface are ground to achieve a flatness of 0.1 μm and a smoothness of Ra0.25 on the sealing surfaces.

[0013] Through the above technical solution, when processing the end cap sealing surface, the flatness and smoothness of the sealing surface are improved by grinding the end cap sealing surface and the tube ball sealing surface, so that the flatness of the sealing surface can reach 0.1μm and the smoothness (i.e., surface roughness) can reach Ra0.25, thereby ensuring the reliability of the seal.

[0014] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the material of the tube ball is 42CrMo; and the material of the guide ring is antimony-impregnated graphite.

[0015] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the clearance fit to be maintained at a high temperature of 300°C is in the range of 0.0005D-0.0015D, where D is the nominal diameter of the sealing fit in mm.

[0016] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, the right end of the housing is provided with an integrally connected housing flange, on which six threaded holes are evenly arranged in a ring; the shape and size of the front cover metal gasket are adapted to the shape and size of the housing flange, and the front cover metal gasket is provided with six through holes evenly arranged in a ring; the left end of the front cover is a front cover flange, the shape and size of which are adapted to the shape and size of the housing flange, and the front cover flange is provided with six through holes evenly arranged in a ring; six external hexagonal bolts with spring washers are respectively passed through the through holes on the front cover flange and the through holes on the front cover metal gasket, and are threaded into the six threaded holes on the housing flange of the housing.

[0017] The above technical solution involves using six external hexagonal bolts with spring washers, which pass through the through holes on the front cover flange and the front cover metal gasket, and are screwed into the threaded holes on the housing flange to firmly connect the front cover and the housing. When the six external hexagonal bolts are tightened evenly, the uniform distribution of the clamping force is ensured, avoiding sealing failure or flange deformation caused by insufficient or excessive local clamping force, and ensuring the sealing reliability of the front end connection.

[0018] As a further explanation of the rotary sealing device for high-temperature heat transfer oil equipment described in this invention, preferably, six threaded holes are evenly arranged in a ring on the left end face of the housing; the shape and size of the rear end cover metal gasket are adapted to the shape and size of the left end face of the housing, and six through holes are evenly arranged in a ring on the rear end cover metal gasket; the right end of the rear end cover is provided with an integrally connected rear end cover flange, the shape and size of the rear end cover flange are adapted to the shape and size of the left end face of the housing, and six through holes are evenly arranged in a ring on the rear end cover flange; six internal hexagonal bolts with spring washers are respectively passed through the through holes on the rear end cover flange and the six through holes on the rear end cover metal gasket, and are threaded into the six threaded holes on the left end face of the housing.

[0019] The above technical solution uses six socket head cap bolts with spring washers to pass through the through holes on the rear end cover flange and the rear end cover metal gasket, and screw them into the threaded holes on the left end face of the housing to firmly connect the front end cover and the housing together. When the six socket head cap bolts are tightened evenly, the uniform distribution of the clamping force is ensured, avoiding sealing failure or flange deformation caused by insufficient or excessive local clamping force, and ensuring the sealing reliability of the rear end connection.

[0020] The beneficial effects of this invention are as follows: 1) The spring of this invention uses a nickel-based high-temperature and corrosion-resistant material with a maximum temperature resistance of 500℃ to ensure that the spring force remains stable at an oil temperature of 300℃, thereby ensuring the reliability and stability of the rotary joint seal; 2) In this invention, the gap between the contact surfaces of the tube ball and the guide ring must still be controlled within the clearance fit range under high-temperature conditions of 300℃, and cannot be within the transition fit or interference fit range, in order to ensure that the tube ball can rotate and swing freely at high temperatures without being stuck, thereby ensuring the reliability of the seal; 3) The material on the sealing surface of the end cap of this invention... The material is heat-resistant steel 42CrMo instead of ordinary carbon steel 45#, and heat treatment is performed to improve the hardness of the sealing surface, eliminate the intramolecular stress in the sealing surface of the end cap, improve the various mechanical properties of the end cap, and reduce the deformation of the sealing surface, thereby improving the wear resistance and sealing performance of the sealing surface; 4) In the processing of the sealing surface of the end cap, the sealing surface of the end cap and the sealing surface of the tube ball are ground to improve the flatness and smoothness of the sealing surface of the end cap, so that the flatness of the sealing surface can reach 0.1μm and the smoothness can reach Ra0.25, so as to ensure the reliability of the seal. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the rotary sealing device of the present invention, applicable to high-temperature heat transfer oil equipment; Figure 2 for Figure 1 Exploded view; Figure 3 for Figure 1A magnified view of a portion of the image. Detailed Implementation

[0022] To further understand the structure, features, and other objectives of the present invention, a detailed description is provided below with reference to the accompanying drawings. The embodiments illustrated in these drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] like Figure 1 and Figure 2 As shown, this embodiment provides a rotary sealing device suitable for high-temperature heat transfer oil equipment, including a rear end 1, a middle component 2 and a front end 3; the rear end 1 is sleeved outside the middle component 2, and the front end 3 is sleeved outside the middle component 2 and connected to the right end of the rear end 1.

[0024] The middle component 2 includes a tube ball 21 with an annular flange. A ball ring 22, fitted onto the tube ball 21, abuts against the right end face of the annular flange of the tube ball 21, forming a tube ball sealing surface B, as shown below. Figure 3 As shown. A support ring 23, sleeved on the tube ball 21, abuts against the left end face of the annular flange of the tube ball 21 to support the parallel tube ball 21. A positioning seat 24, sleeved on the tube ball 21, abuts against the left end face of the support ring 23. A spring 25, sleeved on the tube ball 21, abuts against the left end face of the positioning seat 24 for elastic force compensation. A cylindrical ring 26, sleeved on the tube ball 21, abuts against the left end of the spring 25 to support the parallel tube ball 21. The spring 25 is made of a nickel-based high-temperature and corrosion-resistant alloy, which is a precipitation-hardening nickel-chromium-iron alloy containing niobium and molybdenum. The spring 25 uses a nickel-based high-temperature and corrosion-resistant material that can withstand temperatures up to 500°C, such as Inconel 718 (or GH4169 in GB / T 14992-2025), to ensure that the elastic force of the spring 25 is stable at an oil temperature of 300°C, thereby ensuring the reliability and stability of the rotary joint seal. The mechanical properties of Inconel 718 at high temperatures have been confirmed in the literature, as shown in Table 1 (cited from *Mechanical Seal Technology*, Chemical Industry Press, page 70, Table 6-40). At 538℃, Inconel 718 maintains a creep rupture strength of 71.7 kgf / mm² after 100 hours and 60.5 kgf / mm² after 1000 hours, with a tensile strength of 116.7 kgf / mm² and a yield strength of 96.3 kgf / mm². At 649℃, the tensile strength is 105.5 kgf / mm² and the yield strength is 88.6 kgf / mm². Based on the general rule that material properties decrease with increasing temperature, the strength and creep resistance of alloy materials show a decreasing trend with increasing temperature. Therefore, at an oil temperature below 538℃ (300℃), Inconel 718 possesses sufficient high-temperature mechanical stability and creep resistance, ensuring stable spring operation.

[0025] Table 1 .

[0026] The rear end portion 1 includes a housing 11 and a rear end cover 13 with a raised ring. The housing 11 has a positioning end face, and the raised ring of the rear end cover 13 is engaged with the left end of the positioning end face of the housing 11. The rear end cover 13 is also fixedly connected to the housing 11. A metal gasket 12 for sealing is sandwiched between the housing 11 and the rear end cover 13, forming the rear end portion 1 fitted over the middle component 2. The positioning end face abuts against the left end face of the positioning seat 24 of the middle component 2. A second anti-rotation pin 27 (i.e., an elastic cylindrical pin) is inserted into the positioning seat 24, and the left end of the second anti-rotation pin 27 is embedded in the positioning end face of the housing 11 to prevent the positioning seat 24 from rotating. The positioning seat 24 also facilitates the addition of lubricating grease to protect the bearing. The rear end cover 13 is fitted over the cylindrical ring 26 of the middle component 2 and presses against the left end of the spring 25 of the middle component 2. The rear end cover 13 is fitted with a first anti-rotation pin 14 (i.e., an elastic cylindrical pin), and the right end of the first anti-rotation pin 14 is fitted into the left end face of the column ring 26 to prevent the column ring 26 from rotating.

[0027] The front end portion 3 includes a front end cap 31 with a raised ring. Two first grooves are symmetrically arranged on the right end face of the raised ring of the front end cap 31. A guide ring 32 is embedded in the raised ring of the front end cap 31. Two second grooves are symmetrically arranged on the right end face of the guide ring 32. After the guide ring 32 is assembled into the raised ring of the front end cap 31, the two second grooves align with the two first grooves to form two combined grooves. Each of the two combined grooves is fitted with a guide ring baffle 33. The guide ring baffle 33 is fixedly connected to the front end cap 31, preferably by a cylindrical screw 34. The portion of the guide ring baffle 33 within the second groove of the guide ring 32 is used to press the guide ring 32 to prevent rotation of the guide ring 32, thus forming the front end portion 3 sleeved outside the middle component 2. The front end cap 31 abuts against the right end face of the ball ring 22 of the middle component 2, providing a seal and forming the end cap sealing surface A. The front cover 31 is fixedly connected to the right end of the housing 11 at the rear end 1. A metal gasket 35 for sealing is sandwiched between the housing 11 and the front cover 31. The contact surface C between the guide ring 32 and the tube ball 21 of the middle component 2 (e.g., Figure 3 As shown, it is a clearance fit, and maintains the clearance fit state under high temperature of 300℃ to support the parallel tube ball 21 and allow the tube ball 21 to rotate and swing freely.

[0028] Because the tube ball 21 and the guide ring 32 are made of different materials, their coefficients of linear expansion are also different. Therefore, a clearance fit is used between the guide ring 32 and the tube ball 21. This clearance fit must be maintained even at a high temperature of 300°C, and cannot be within the range of an interference fit or a transition fit. This ensures that the tube ball 21 can rotate and swing freely at high temperatures without getting stuck, thus ensuring the reliability of the seal. In some embodiments, the tube ball 21 is made of heat-resistant steel 42CrMo, with a coefficient of linear expansion of 12.5 x 10⁻⁶. -6 / ℃ (the value is slightly lower than the standard value to allow for a safety margin); the guide ring 32 is made of antimony-impregnated graphite, and its coefficient of linear expansion is approximately 5.0 x 10⁻⁶. -6 / ℃ (see references such as "Antimony-Impregnated Graphite - A Novel Solid Lubricating Material"). The clearance fit design between the tube ball 21 and the guide ring 32 is as follows: the initial clearance at room temperature = the clearance to be maintained at high temperature + the difference in clearance change caused by temperature rise, to ensure that the tube ball 21 and the guide ring 32 always maintain a clearance fit under the high temperature of 300℃. The initial clearance at room temperature of the rotary sealing device does not have a uniform fixed range, but is specially designed according to the material pairing, working temperature, diameter, etc. The following is only an example of how to calculate a suitable initial clearance at room temperature through the law of thermal expansion deformation, and does not constitute any numerical limitation on the scope of protection of this invention. For the high temperature rotary sealing pair of 42CrMo tube ball and antimony-impregnated graphite guide ring described in this embodiment, in order to take into account the sealing performance and rotation flexibility under high temperature conditions, the single-sided clearance (clearance fit) to be maintained at 300℃ is set in the range of 0.0005D-0.0015D (D is the nominal diameter of the sealing fit, in mm). Then T 常温 At 20℃, T 高温 =300℃, temperature difference ΔT=280℃, linear expansion coefficient of 42CrMo tube sphere α1=12.5X10 -6 / ℃, the linear expansion coefficient α2 of antimony-impregnated graphite guide ring is 5.0 x 10⁻⁶. -6 At / ℃, based on the radial thermal expansion deformation law (refer to "Mechanical Design Handbook" (5th edition, Chemical Industry Press), the difference in unilateral clearance change Δδ caused by temperature rise at the mating parts is: Δδ=D·(α1-α2)·ΔT=DX7.5X10 -6 X280 = 0.0021D; The initial clearance on one side at room temperature is within the range of 0.0026D-0.0036D, which ensures a clearance fit throughout the entire process and allows for free rotation without jamming. Similarly, the column ring 26 and the support ring 23 are both made of the same antimony-impregnated graphite material as the guide ring 32, and their fit with the tube ball 21 also adopts the same clearance fit design principle, that is, a clearance fit must be maintained at a high temperature of 300℃ to ensure that the tube ball 21 can rotate and swing freely in all mating positions without being jammed.

[0029] To address the issue of ordinary carbon steel being used for the end cap sealing surface without heat treatment to control its hardness, leading to deformation and insufficient hardness causing wear and leakage, some embodiments use heat-resistant steel 42CrMo instead of ordinary carbon steel 45# for both the end cap sealing surface A and the tube ball sealing surface B. This increases the hardness of the sealing surface, reduces deformation, and improves wear resistance and sealing performance. 42CrMo possesses excellent high-temperature stability, strength, and wear resistance, significantly reducing deformation under high-temperature conditions. In other embodiments, the end cap sealing surface A and the tube ball sealing surface B undergo quenching and tempering treatment to further enhance hardness. Quenching and tempering refers to a double heat treatment process involving quenching followed by high-temperature tempering of the steel. The typical process for quenching and tempering is as follows: 42CrMo is heated to 840~880℃ and quenched (oil-cooled or water-based quenching fluid-cooled), followed by high-temperature tempering at 550~650℃ for 2-4 hours to obtain a uniform tempered sorbite structure. Before quenching and tempering, the basic hardness of the 42CrMo blank material is 16-18 HRC on the Rockwell, while after quenching and tempering, the hardness of the sealing surface is increased to 30-33 HRC, ensuring both sufficient wear resistance and deformation resistance.

[0030] To address the problem of insufficient machining precision of the sealing surface, resulting in compromised smoothness and flatness and potential leakage, in some embodiments, the end cap sealing surface A and the tube ball sealing surface B are ground to achieve a flatness of 0.1 μm and a smoothness (i.e., surface roughness) of Ra0.25, thereby ensuring reliable sealing. Specifically, when machining the end cap sealing surface, commercially available grinding equipment can be used, as long as it can achieve a flatness of 0.1μm and a surface finish of Ra0.25 on the sealing surface. Examples include the JX-610BXQ grinding machine from Shenzhen Jinxin Precision Machinery Co., Ltd., and the YH2M8195 grinding machine from Yuhuan CNC. Place the workpiece to be ground on its ductile iron cast circular grinding disc, add the prepared grinding paste to the disc, adjust the rotation speed of the disc to 50-60 rpm using a frequency converter, and press the disc onto the workpiece using a cylinder extending from above the disc. The pressure is adjusted according to the size of the workpiece and via a pressure regulating valve. Grind for about 10 minutes, then remove the disc and polish the surface. Finally, use an optical flat to check its flatness; the surface should have at least three light bands.

[0031] In some embodiments, such as Figure 2 As shown, the right end of the housing 11 is provided with an integrally connected housing flange, on which six threaded holes are evenly arranged in a ring. The shape and size of the front cover metal gasket 35 are adapted to the shape and size of the housing flange, and the front cover metal gasket 35 is provided with six through holes evenly arranged in a ring. The left end of the front cover 31 is a front cover flange, the shape and size of which are adapted to the shape and size of the housing flange, and the front cover flange is provided with six through holes evenly arranged in a ring. Six external hexagonal bolts 36 with spring washers are respectively inserted into the through holes on the front cover flange of the front cover 31 and the through holes on the front cover metal gasket 35, and are threaded into the six threaded holes on the housing flange of the housing 11. By passing six external hex bolts with spring washers through the through holes on the front cover flange and the front cover metal gasket, and screwing them into the threaded holes on the housing flange, the front cover and the housing are firmly connected together. When the six external hex bolts are tightened evenly, the uniform distribution of the clamping force is ensured, avoiding sealing failure or flange deformation caused by insufficient or excessive local clamping force, and ensuring the sealing reliability of the front end connection.

[0032] In some embodiments, such as Figure 2As shown, six threaded holes are evenly arranged in a ring on the left end face of the housing 11. The shape and size of the rear end cover metal gasket 12 are adapted to the shape and size of the left end face of the housing 11, and six through holes are evenly arranged in a ring on the rear end cover metal gasket 12. The right end of the rear end cover 13 is provided with an integrally connected rear end cover flange, the shape and size of which are adapted to the shape and size of the left end face of the housing 11, and six through holes are evenly arranged in a ring on the rear end cover flange. Six socket head cap bolts 15 with spring washers are respectively inserted into the through holes on the rear end cover flange of the rear end cover 13 and the six through holes on the rear end cover metal gasket 12, and are threaded into the six threaded holes on the left end face of the housing 11. By passing six socket head cap bolts with spring washers through the through holes on the rear end cover flange and the rear end cover metal gasket, and screwing them into the threaded holes on the left end face of the housing, the front end cover and the housing are firmly connected together. When the six socket head cap bolts are tightened evenly, the uniform distribution of the clamping force is ensured, avoiding sealing failure or flange deformation caused by insufficient or excessive local clamping force, and ensuring the sealing reliability of the rear end connection.

[0033] In this embodiment, the rotary sealing device for high-temperature heat transfer oil equipment operates as follows: the housing 11 connects to the inlet pipe, the right end of the tube ball 21 connects to the equipment, and the column ring 26, support ring 23, and guide ring 32 support the parallel tube ball 21, which rotates relative to the housing 11. A constant axial preload is provided by a nickel-based high-temperature and corrosion-resistant alloy spring 25, ensuring that the annular flange on the tube ball 21 and the ball ring 22, as well as the ball ring 22 and the front end cover 31, form a sealing surface that remains tightly fitted, achieving a double seal. By using materials with different expansion coefficients for the tube ball 21 and the guide ring 32 and maintaining a clearance fit, thermal expansion and compression jamming at 300°C are avoided. Each sealing surface uses a high-strength 42CrMo sealing end face to reduce high-temperature deformation and improve wear resistance. The positioning seat 24, the second anti-rotation pin 27, and the column ring 26 cooperate to achieve circumferential limiting, ensuring structural stability and reducing offset and shaking. The overall rotary sealing device structure is adapted to high-temperature heat transfer oil conditions of 280-300°C, reducing the probability of leakage. To prevent damage to the sealing surface from media deterioration, the high-temperature heat transfer oil must be able to withstand temperatures above 300℃. If the heat transfer oil cannot withstand temperatures above 300℃, it is prone to coking and carbonization under high-temperature conditions of 280℃-300℃, making the sealing surface easily scratched and causing leakage. At the same time, it is necessary to ensure that when the annular flange on the tube ball 21 and the ball ring 22, and the ball ring 22 and the front end cover 31 are ground together, a continuous closed sealing bright band (i.e., an annular mirror contact band formed after grinding) is formed on the sealing surface to ensure the stability of the seal.

[0034] It should be stated that the above-described invention content and specific embodiments are intended to demonstrate the practical application of the technical solution provided by this invention and should not be construed as limiting the scope of protection of this invention. Those skilled in the art can make various modifications, equivalent substitutions, or improvements within the spirit and principles of this invention. The scope of protection of this invention is defined by the appended claims.

Claims

1. A rotary sealing device suitable for high-temperature heat transfer oil equipment, characterized in that, It includes a rear end (1), a middle component (2), and a front end (3); the rear end (1) is fitted over the middle component (2), and the front end (3) is fitted over the middle component (2) and connected to the right end of the rear end (1); wherein, The middle component (2) includes a tube ball (21) with an annular flange; a ball ring (22) fitted on the tube ball (21) abuts against the right end face of the annular flange of the tube ball (21) and forms a tube ball sealing surface (B); a support ring (23) fitted on the tube ball (21) abuts against the left end face of the annular flange of the tube ball (21) to support the parallel tube ball (21); a positioning seat (24) fitted on the tube ball (21) abuts against the left end face of the support ring (23); a spring (25) fitted on the tube ball (21) abuts against the left end face of the positioning seat (24) for elastic force compensation; the spring (25) is made of nickel-based high temperature and corrosion resistant alloy to ensure elastic force stability at a high temperature of 300°C; a column ring (26) fitted on the tube ball (21) abuts against the left end of the spring (25) to support the parallel tube ball (21). The rear end (1) includes a housing (11) and a rear end cover (13) with a protruding ring. The housing (11) has a positioning end face. The protruding ring of the rear end cover (13) is engaged in the left end of the positioning end face of the housing (11). A metal gasket (12) for sealing is sandwiched between the housing (11) and the rear end cover (13) to form the rear end (1) sleeved outside the middle component (2). The right end of the positioning end face abuts against the left end of the positioning seat (24) of the middle component (2). On the side, a second anti-rotation pin (27) is inserted into the positioning seat (24), and the left end of the second anti-rotation pin (27) is embedded in the positioning end face of the housing (11) to prevent the positioning seat (24) from rotating; the rear end cover (13) is sleeved on the outside of the column ring (26) of the middle component (2) and presses against the left end of the spring (25) of the middle component (2); the rear end cover (13) is embedded with a first anti-rotation pin (14), and the right end of the first anti-rotation pin (14) is embedded in the left end face of the column ring (26) to prevent the column ring (26) from rotating. The front end portion (3) includes a front end cap (31) with a convex ring. Two first grooves are symmetrically provided on the right end face of the convex ring of the front end cap (31). A guide ring (32) is embedded in the convex ring of the front end cap (31). Two second grooves are symmetrically provided on the right end face of the guide ring (32). The two second grooves correspond to the two first grooves to form two combined grooves. A guide ring baffle (33) is embedded in each of the two combined grooves. The guide ring baffle (33) is fixedly connected to the front end cap (31) and presses the guide ring (32) to prevent the guide ring (32) from rotating, so as to form the front end portion (3) sleeved outside the middle component (2). The front end cap (31) abuts against the right end face of the ball ring (22) of the middle component (2) to seal with the ball ring (22) and form the end cap sealing surface (A); the front end cap (31) is fixedly connected to the right end of the housing (11) of the rear end (1), and a front end cap metal gasket (35) for sealing is sandwiched between the housing (11) and the front end cap (31); the contact surface (C) between the guide ring (32) and the tube ball (21) of the middle component (2) is clearance fit, and the clearance fit is maintained under the working condition of high temperature 300℃ to support the parallel tube ball (21) and allow the tube ball (21) to rotate and swing freely.

2. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The nickel-based high-temperature and corrosion-resistant alloy is Inconel 718.

3. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The end cap sealing surface (A) and the tube ball sealing surface (B) are made of 42CrMo.

4. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The end cap sealing surface (A) and the tube ball sealing surface (B) are heat-treated to achieve a hardness of 30-33 HRC.

5. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The end cap sealing surface (A) and the tube ball sealing surface (B) are ground to achieve a flatness of 0.1μm and a smoothness of Ra0.

25.

6. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The tube ball (21) is made of 42CrMo; the guide ring (32) is made of antimony-impregnated graphite.

7. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The clearance fit to be maintained at 300℃ is set to be within the range of 0.0005D-0.0015D, where D is the nominal diameter of the sealing fit in mm.

8. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The right end of the housing (11) is provided with an integrally connected housing flange, and the housing flange is provided with six threaded holes evenly arranged in a ring; The shape and size of the front cover metal gasket (35) are adapted to the shape and size of the housing flange, and six through holes are uniformly arranged on the front cover metal gasket (35); The left end of the front cover (31) is the front cover flange. The shape and size of the front cover flange are adapted to the shape and size of the housing flange. The front cover flange is provided with six through holes in a uniform ring. Six external hex bolts (36) with spring washers are respectively inserted into the through holes on the front cover flange of the front cover (31) and the through holes on the front cover metal gasket (35), and are threaded into the six threaded holes on the housing flange of the housing (11).

9. The rotary sealing device for high-temperature heat transfer oil equipment as described in claim 1, characterized in that, The left end face of the housing (11) is provided with six threaded holes evenly arranged in a ring; The shape and size of the rear end cover metal gasket (12) are adapted to the shape and size of the left end face of the housing (11), and six through holes are uniformly arranged on the rear end cover metal gasket (12); The right end of the rear cover (13) is provided with an integrally connected rear cover flange. The shape and size of the rear cover flange are adapted to the shape and size of the left end face of the housing (11). The rear cover flange is provided with six through holes in a uniform ring. Six socket head cap bolts (15) with spring washers are respectively inserted into the through holes on the rear end cover flange of the rear end cover (13) and the six through holes on the rear end cover metal gasket (12), and are threaded into the six threaded holes on the left end face of the housing (11).

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