Self-locking sealing structure and method for silicon carbide heat exchanger

Abstract

The invention relates to the technical field of heat exchangers, and discloses a self-locking sealing structure and method for a silicon carbide heat exchanger. The combined sealing ring consists of an upper polytetrafluoroethylene sealing seat, a lower polytetrafluoroethylene sealing seat and a locking ring; wherein the teflon upper sealing seat and the teflon lower sealing seat are respectively arranged at the upper end and the lower end of the locking ring; and the compression nut is matched with the step-shaped threaded pipe hole in the pipe plate and can be screwed in the step-shaped threaded pipe hole, and when the step-shaped threaded pipe hole is screwed, the compression nut compresses the combined sealing ring on the pipe plate to complete sealing. By adopting a self-locking structure and a multi-layer sealing design, the sealing effect is enhanced by utilizing medium pressure, an expensive perfluoroether O-shaped ring does not need to be used in a strong corrosive medium, the manufacturing, using and maintaining cost is reduced, more reliable sealing can be provided, and the sealing performance is kept under higher pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a self-locking sealing structure and method for a silicon carbide heat exchanger. Background Art

[0002] Silicon carbide heat exchange tubes have the characteristics of strong corrosion resistance, high thermal conductivity, high temperature and high pressure resistance, stable thermal shock performance, and long service life. Silicon carbide heat exchangers with silicon carbide heat exchange tubes as heat transfer elements are increasingly widely used in harsh working conditions such as strong corrosion. However, the sealing of the heat exchange tubes and tube sheets of silicon carbide heat exchangers has not been well solved. At present, fluororubber or perfluoroether O-ring sealing structures are generally used. In order to ensure the sealing effect, double-tube sheet multi-layer O-rings are often used. The large number of high-fluororubber or perfluoroether O-rings greatly increases the manufacturing cost of silicon carbide heat exchangers. Not only that, due to the easy aging of rubber, frequent replacement of O-rings makes the use and maintenance costs of silicon carbide heat exchangers high, which seriously affects the promotion and application of silicon carbide heat exchangers. Therefore, it is particularly important to develop a sealing structure with long service life, stable sealing performance, and low maintenance cost for the promotion and application of silicon carbide heat exchangers. Summary of the invention

[0003] In view of the above-mentioned technical deficiencies, the technical problem to be solved by the present invention is to provide a self-locking sealing structure for a silicon carbide heat exchanger, aiming to solve the problems of unstable sealing performance between heat exchange tubes and tube sheets of the current silicon carbide heat exchanger and high maintenance cost.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a self-locking sealing structure for a silicon carbide heat exchanger, comprising: A tube sheet provided with stepped threaded tube holes; Combined sealing ring consisting of a PTFE upper sealing seat, a PTFE lower sealing seat and a locking ring; Wherein, the PTFE upper sealing seat and the PTFE lower sealing seat are respectively arranged at the upper and lower ends of the locking ring; The compression nut matches the stepped threaded tube hole on the tube sheet and can be screwed into the stepped threaded tube hole. When screwed in, the compression nut presses the combined sealing ring onto the tube sheet to complete the sealing.

[0005] Furthermore, the longitudinal cross-section of the polytetrafluoroethylene upper sealing seat and the polytetrafluoroethylene lower sealing seat is a right triangle.

[0006] Furthermore, the longitudinal cross-section of the locking ring is a trapezoidal structure in which one end of two oblique sides is connected to one end of the corresponding long side through a side perpendicular to the corresponding long side.

[0007] Furthermore, the long side of the trapezoidal structure is in close contact with the outer wall of the silicon carbide heat exchange tube; and the two oblique sides are respectively matched with the polytetrafluoroethylene upper sealing seat and the polytetrafluoroethylene lower sealing seat.

[0008] Furthermore, the locking ring is formed by a soft polytetrafluoroethylene inner ring and a hard polytetrafluoroethylene outer ring which are nested in sequence from the inside to the outside.

[0009] Furthermore, the hard polytetrafluoroethylene outer ring is also provided with at least one beveled notch.

[0010] A self-locking sealing structure for a silicon carbide heat exchanger is used.

[0011] A self-locking sealing method for a silicon carbide heat exchanger comprises the following steps: Preset stepped threaded pipe holes on the tube sheet; Put the combined sealing ring into the pipe hole, and align the upper PTFE sealing seat and the lower PTFE sealing seat with the upper and lower positions of the pipe hole respectively; Install the locking ring between the PTFE upper seal seat and the PTFE lower seal seat, and ensure that the locking ring fits correctly with the PTFE upper seal seat and the PTFE lower seal seat; Use the compression nut to tighten the stepped threaded pipe hole on the tube sheet until the combined sealing ring is completely compressed; Check the combined seal ring for leakage. If leakage is found, adjust the tightening force of the compression nut or replace the damaged parts.

[0012] The beneficial effects of the present invention are: 1. The highly corrosive medium of the present invention does not need to use expensive perfluoroether O-rings, which can reduce the manufacturing, use and maintenance costs.

[0013] 2. The present invention adopts a self-locking structure, and the single-side medium pressure can squeeze the locking ring, making the sealing effect of the soft PTFE sealing ring more reliable.

[0014] 3. Compared with the O-ring sealing structure, the new structure of the present invention can withstand the sealing of higher pressure media. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic structural diagram of a self-locking sealing structure for a silicon carbide heat exchanger provided in an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of the explosion of the combined sealing ring.

[0018] Figure 3 for Figure 2 Top view of the middle locking ring.

[0019] Explanation of the reference numerals: 1. tube sheet; 2. compression nut; 3. combined sealing ring; 4. silicon carbide heat exchange tube; 31. PTFE upper sealing seat; 32. PTFE lower sealing seat; 33. locking ring; 331. hard PTFE outer ring; 332. soft PTFE inner ring; 331a. bevel notch. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1

[0022] like Figures 1 to 3 As shown, this embodiment provides a self-locking sealing structure for a silicon carbide heat exchanger, including: a tube sheet 1 provided with a stepped threaded tube hole; a combined sealing ring 3 composed of a polytetrafluoroethylene upper sealing seat 31, a polytetrafluoroethylene lower sealing seat 32 and a locking ring 33; wherein the polytetrafluoroethylene upper sealing seat 31 and the polytetrafluoroethylene lower sealing seat 32 are respectively arranged at the upper and lower ends of the locking ring 33; a clamping nut 2, which matches the stepped threaded tube hole on the tube sheet 1 and can be screwed into the stepped threaded tube hole. When tightened, the clamping nut 2 presses the combined sealing ring 3 on the tube sheet 1 to complete the sealing.

[0023] The longitudinal cross-sections of the PTFE upper sealing seat 31 and the PTFE lower sealing seat 32 are right triangles, which can form a V-shaped groove.

[0024] The longitudinal cross section of the locking ring 33 is a trapezoidal structure in which one end of two oblique sides is connected to one end of the corresponding long side through a side perpendicular to the corresponding long side.

[0025] It should be noted that the bevel design of this trapezoidal structure avoids sharp corners. First, it can better adapt to the outer wall shape of the silicon carbide heat exchange tube 4 when under pressure, ensuring the tight fit of the sealing interface; the bevel can provide a certain deformation space, so that the locking ring 33 can more evenly squeeze the soft polytetrafluoroethylene inner ring 332 inward when under pressure; in addition, the standard trapezoidal structure may produce stress concentration at sharp corners, which is easy to crack or damage in long-term use, while the trapezoidal structure can disperse stress and improve durability and service life through the design of bevel. Finally, this type of trapezoidal structure allows a certain degree of installation error. The design of the bevel can provide a certain tolerance space during the installation process. Even if the installation position is slightly deviated, it can be adjusted through the deformation of the bevel, thereby ensuring the sealing effect.

[0026] The long side of the trapezoidal structure is in close contact with the outer wall of the silicon carbide heat exchange tube 4 ; the two oblique sides are matched with the polytetrafluoroethylene upper sealing seat 31 and the polytetrafluoroethylene lower sealing seat 32 respectively.

[0027] The locking ring 33 is formed by a soft polytetrafluoroethylene inner ring 332 and a hard polytetrafluoroethylene outer ring 331 which are nested in sequence from the inside to the outside.

[0028] The hard PTFE outer ring 331 is also provided with at least one beveled notch 331a; the design of the beveled notch 331a helps to guide the silicon carbide heat exchange tube 4 into position correctly during installation, and promotes good contact between the hard PTFE sealing seat and the silicon carbide heat exchange tube 4 during the pressing process.

[0029] Example 2

[0030] Based on Example 1, this example further provides a silicon carbide heat exchanger, the sealing structure of which adopts a self-locking sealing structure for a silicon carbide heat exchanger in Example 1.

[0031] Example 3

[0032] Based on Example 1, this embodiment also provides a sealing method for a self-locking sealing structure of a silicon carbide heat exchanger, comprising the following steps: A stepped threaded tube hole is preset on the tube sheet 1; Place the combined sealing ring 3 into the pipe hole, and align the upper PTFE sealing seat 31 and the lower PTFE sealing seat 32 with the upper and lower positions of the pipe hole respectively; Install the locking ring 33 between the PTFE upper sealing seat 31 and the PTFE lower sealing seat 32 to ensure that the locking ring 33 is properly matched with the PTFE upper sealing seat 31 and the PTFE lower sealing seat 32; Use the compression nut 2 to tighten the stepped threaded pipe hole on the tube sheet 1 until the combined sealing ring 3 is completely compressed; Check whether the combined sealing ring 3 has any leakage. If leakage is found, adjust the tightening force of the clamping nut 2 or replace the damaged parts to achieve a satisfactory sealing effect.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A self-locking sealing structure for a silicon carbide heat exchanger, characterized in that: include: A tube sheet provided with stepped threaded tube holes; Combined sealing ring consisting of a PTFE upper sealing seat, a PTFE lower sealing seat and a locking ring; Wherein, the PTFE upper sealing seat and the PTFE lower sealing seat are respectively arranged at the upper and lower ends of the locking ring; The compression nut matches the stepped threaded tube hole on the tube sheet and can be screwed into the stepped threaded tube hole. When screwed in, the compression nut presses the combined sealing ring onto the tube sheet to complete the sealing.

2. A self-locking sealing structure for a silicon carbide heat exchanger according to claim 1, characterized in that: The longitudinal cross-sections of the polytetrafluoroethylene upper sealing seat and the polytetrafluoroethylene lower sealing seat are right-angled triangles.

3. A self-locking sealing structure for a silicon carbide heat exchanger according to claim 1, characterized in that: The longitudinal cross section of the locking ring is a trapezoidal structure in which one end of two oblique sides is connected to one end of the corresponding long side through a side perpendicular to the corresponding long side.

4. A self-locking sealing structure for a silicon carbide heat exchanger according to claim 3, characterized in that: The long side of the trapezoidal structure is in close contact with the outer wall of the silicon carbide heat exchange tube; and the two oblique sides are respectively matched with the polytetrafluoroethylene upper sealing seat and the polytetrafluoroethylene lower sealing seat.

5. A self-locking sealing structure for a silicon carbide heat exchanger according to claim 1, characterized in that: The locking ring is formed by nesting a soft polytetrafluoroethylene inner ring and a hard polytetrafluoroethylene outer ring in sequence from inside to outside.

6. A self-locking sealing structure for a silicon carbide heat exchanger according to claim 1, characterized in that: The hard polytetrafluoroethylene outer ring is also provided with at least one beveled notch.

7. A heat exchanger for silicon carbide, characterized in that: A self-locking sealing structure for a silicon carbide heat exchanger as described in claims 1 to 6 is adopted.

8. A sealing method for a self-locking sealing structure for a silicon carbide heat exchanger according to any one of claims 1 to 6, characterized in that: The following steps are involved: Preset stepped threaded pipe holes on the tube sheet; Put the combined sealing ring into the pipe hole, and align the upper PTFE sealing seat and the lower PTFE sealing seat with the upper and lower positions of the pipe hole respectively; Install the locking ring between the PTFE upper seal seat and the PTFE lower seal seat, and ensure that the locking ring fits correctly with the PTFE upper seal seat and the PTFE lower seal seat; Use the compression nut to tighten the stepped threaded pipe hole on the tube sheet until the combined sealing ring is completely compressed; Check the combined seal ring for leakage. If leakage is found, adjust the tightening force of the compression nut or replace the damaged parts.

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