Gas-phase deposition furnace and installation method of packing seal structure

Abstract

The present application provides an installation method for a chemical vapor deposition furnace and a packing seal structure. The chemical vapor deposition furnace includes a furnace tube, a lower tube sheet, and a packing seal structure. The furnace tube passes through the lower tube sheet, and the furnace tube and the lower tube sheet are sealed by the packing seal structure. The packing seal structure includes packing, a tube seat, a gland, and an ear structure. The tube seat is fixedly connected to the lower tube sheet. The ear structure includes a nut, a connecting plate, and a screw rod. The connecting plate is fixedly connected to the gland. The screw rod can pass through the connecting plate. One end of the screw rod is fixedly connected to the lower tube sheet. The screw rod and the nut are connected by a threaded fit. The position of the connecting plate in the axial direction of the screw rod can be restricted by the nut.

Description

Technical Field

[0001] The present application relates to a chemical vapor deposition furnace, and particularly to a chemical vapor deposition furnace with a packing seal structure and an installation method of the packing seal structure. Background Art

[0002] As a complete set of process technology devices for green and efficient preparation of catalysts, the deposition process occurring in the chemical vapor deposition furnace requires the uniformity of the feed of each furnace tube and the uniform temperature distribution inside the furnace tube. At the same time, when hydrogen chloride generated by the reaction during the deposition process leaves the high-temperature area, there is a certain possibility that it will condense with water vapor in the air to form hydrochloric acid, causing corrosion. Therefore, it is required that the seal between the furnace tube and the tube sheet is reliable to prevent hydrogen chloride from leaking.

[0003] In an existing technology, the chemical vapor deposition furnace includes a heating chamber, an upper tube sheet above the heating chamber, a lower tube sheet below the heating chamber, and 90 furnace tubes with a diameter of 159 mm passing through the lower tube sheet, the heating chamber, and the upper tube sheet. As Figure 1 shown, the furnace tube 1 is welded to the upper tube sheet (not shown), and the furnace tube 1 and the lower tube sheet 2 are sealed through a packing seal structure. Specifically, the packing seal structure in the existing technology includes a tube seat 51, a gland 61, packing 4 (such as graphite), and a gasket 3. The tube seat 51 has a fine thread internal thread of M200 and is welded to the lower tube sheet 2. The gland 61 has a fine thread external thread of M200, and the gland 61 is screwed into the tube seat 51 through thread engagement to compress the packing 4. The packing 4 is radially tightened under the action of the axial force of the gland 61, thereby playing a sealing role.

[0004] The existing technology has the following problems:

[0005] 1. The assembly requirements for thread engagement are relatively high, and the operation posture during assembly is upward (installing from bottom to top), which is not conducive to assembly and poses a safety hazard. In addition, this solution requires special tooling and multiple operators. For example, one person holds the tooling and two people screw it in. It occupies a large operating space and is time-consuming and laborious.

[0006] 2. Welding stress will exist when the tube seat 51 is welded to the lower tube sheet 2, which may cause changes in thread dimensions, roundness, etc., resulting in the gland 61 being blocked from screwing in and unable to evenly extrude the packing 4, affecting the sealing state.

[0007] 3. The temperature of the furnace tube 1 is relatively high (for example, reaching 700 °C). Under continuous high temperature, the thread of the tube seat 51 will be deformed, resulting in the gland 61 being blocked from screwing in and unable to evenly extrude and compress the packing 4, affecting the sealing state.

[0008] 4. The lower tube sheet 2 and the furnace tubes 1 may not be completely perpendicular, resulting in the furnace tubes 1 and the tube sockets 51 being non-concentric and the gaps between the furnace tubes 1 and the tube sockets 51 being uneven after the tube sockets 51 are welded to the lower tube sheet 2. As a result, the gland 61 is difficult to screw in, making it difficult to uniformly extrude and compress the packing 4 and affecting the sealing state. Moreover, during the temperature rise and fall cycle of the heating chamber during operation, the furnace tubes 1 will undergo telescopic deformation and displacement. The non-concentricity of the furnace tubes 1 and the tube sockets 51 and the uneven gaps between the furnace tubes 1 and the tube sockets 51 will cause slight bending of the furnace tubes 1 during the movement and expansion of the furnace tubes 1, further affecting the sealing between the furnace tubes 1 and the tube sockets 51. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present application proposes an installation method for a chemical vapor deposition furnace and a packing seal structure.

[0010] The chemical vapor deposition furnace proposed by the present application includes furnace tubes, a lower tube sheet, and a packing seal structure. The furnace tubes pass through the lower tube sheet, and the furnace tubes and the lower tube sheet form a seal through the packing seal structure.

[0011] The packing seal structure includes packing, tube sockets, a gland, and an ear structure. The tube sockets are fixedly connected to the lower tube sheet.

[0012] The ear structure includes a nut, a connecting plate, and a screw. The connecting plate is fixedly connected to the gland. The screw can pass through the connecting plate. One end of the screw is fixedly connected to the lower tube sheet. The screw and the nut are connected by a threaded fit. The position of the connecting plate in the axial direction of the screw can be limited by the nut.

[0013] In at least one embodiment, the screw is welded to the lower tube sheet.

[0014] In at least one embodiment, the connecting plate is welded to the gland.

[0015] In at least one embodiment, at least a part of the gland is inserted into the tube socket, and the gland and the tube socket are in clearance fit.

[0016] In at least one embodiment, the packing seal structure includes multiple groups of the ear structures, and the position of the gland in the axial direction is adjusted by adjusting the positions of the multiple nuts on their corresponding screws.

[0017] In at least one embodiment, the gland and the tube socket are coaxially arranged.

[0018] In at least one embodiment, the connecting plate has a hole, and the diameter of the hole is larger than the diameter of the screw, so that the screw can displace and tilt relative to the connecting plate.

[0019] The packing seal structure in the installation method of the packing seal structure proposed in this application is the packing seal structure of the aforementioned vapor deposition furnace. The furnace tube and the lower tube plate of the vapor deposition furnace are sealed through the packing seal structure.

[0020] The installation method of the packing seal structure includes:

[0021] The gland is pre-installed into the socket, and the screw passes through the connecting plate and is placed beside the gland to determine the fixed position of the screw;

[0022] The screw is fixedly connected to the lower tube plate of the vapor deposition furnace;

[0023] The connecting plate is fixedly connected to the gland; and

[0024] The nut is screwed with the screw, and the position of the gland in the axial direction is adjusted by changing the position of the nut.

[0025] In at least one embodiment, the packing seal structure includes multiple groups of the lug structures. By adjusting the positions of the nuts of some of the multiple groups of the lug structures on the screw, the position and posture of the gland are adjusted.

[0026] This application cancels the thread engagement between the socket and the gland in the prior art. The position of the gland is restricted by the lug structures fixedly connected to the gland and the lower tube plate respectively, realizing the cooperation between the socket and the gland, and avoiding or improving the problem that the packing cannot be evenly extruded due to the thread engagement connection, affecting the sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shows a cross-sectional schematic view of a packing seal structure for a vapor deposition furnace in the prior art.

[0028] Figure 2 Shows a cross-sectional schematic view of a packing seal structure for a vapor deposition furnace according to an embodiment of the present application.

[0029] Figure 3 is Figure 2 a bottom view of.

[0030] Explanation of Reference Numerals

[0031] 1 Furnace tube; 2 Lower tube plate; 3 Gasket; 4 Packing; 51 Socket; 52 Socket; 61 Gland; 62 Gland; 7 Lug structure; 71 Nut; 72 Connecting plate; 73 Screw;

[0032] A Axial direction; R Radial direction. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The exemplary embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, rather than to exhaust all feasible ways of the present application, nor to limit the scope of the present application.

[0034] As Figure 2 , 3 shown, the present application provides a chemical vapor deposition furnace, which includes a heating chamber (not shown), an upper tube sheet (not shown) at the upper part of the heating chamber, a lower tube sheet 2 at the lower part of the heating chamber, and a furnace tube 1 passing through the lower tube sheet 2, the heating chamber, and the upper tube sheet. For the convenience of describing the direction, the present application introduces the axial direction A and the radial direction R of the furnace tube / screw (introduced later).

[0035] The chemical vapor deposition furnace further includes a packing seal structure. The packing seal structure includes a gasket 3, packing 4, a tube seat 52, a gland 62, and an ear structure 7. The furnace tube 1 is fixedly connected to the upper tube sheet (not shown), and the tube seat 52 is fixedly connected to the lower tube sheet 2. The axis of the tube seat 52 is substantially perpendicular to the lower tube sheet 2. It can be understood that it is difficult to ensure that the axis of the tube seat 52 is absolutely perpendicular to the lower tube sheet 2 when the tube seat 52 and the lower tube sheet 2 are connected by welding. The furnace tube 1 and the lower tube sheet 2 are sealed by the packing seal structure. The gasket 3 and the packing 4 are located inside the tube seat 52, and the gland 62 is at least partially inserted into the tube seat 52. When the packing 4 is subjected to the axial force of the gland 62, it expands radially, thereby playing a sealing role. The packing 4 can be graphite.

[0036] The ear structure 7 may include a nut 71, a connecting plate 72, and a screw 73. The connecting plate 72 has a hole, and the diameter of the hole is larger than the diameter of the screw 73. The screw 73 passes through the connecting plate 72, so that the screw 73 can displace and rotate relative to the connecting plate 72. The connecting plate 72 is fixedly connected to the gland 62, that is, the position of the gland 62 can be adjusted by adjusting the position of the connecting plate 72. For example, the connecting plate 72 and the gland 62 can be connected by welding.

[0037] The screw 73 can pass through the connecting plate 72, that is, the connecting plate 72 can move relative to the screw 73 in the axial direction A. One end (the upper end in the axial direction A) of the screw 73 is fixedly connected to the lower tube sheet 2. The position of the connecting plate 72 in the radial direction R can be determined by the fixed position of the screw 73. The screw 73 and the nut 71 are connected by a threaded fit. The connecting plate 72 is located between the nut 71 and the lower tube sheet 2. By adjusting the nut 71, the connecting plate 72 can be pushed to move along the axial direction A, so that the gland 62 presses the packing 4.

[0038] The packing seal structure may include multiple groups of lug structures 7, and the multiple groups of lug structures 7 may be evenly arranged along the circumferential direction of the gland 62. For example, one gland 62 corresponds to three or four groups of lug structures 7. By adjusting the positions of the nuts 71 of some of the lug structures in the multiple groups of lug structures on the screw rods 73, the position and posture of the gland 62 can be adjusted (such as moving and tilting). By adjusting the position and posture of the gland 62 through the nuts 71 of the multiple groups of lug structures, the coaxiality between the gland 62 and the pipe socket 52 can be more easily controlled and it is not easy to get stuck.

[0039] During the heating and cooling process, the furnace tube 1 may move in the radial direction R. In this application, the position and posture of the gland 62 are adjustable, so that the gland 62 and the pipe socket 52 are coaxial, which to a certain extent avoids the furnace tube 1 from being blocked during movement, causing the furnace tube 1 to bend, and can also maintain the sealed state between the furnace tube 1 and the pipe socket 52 when the furnace tube 1 moves.

[0040] The installation method of the above-mentioned packing seal structure includes:

[0041] Install the packing 4 and the gasket 3 inside the pipe socket 52. The packing 4 and the gasket 3 are arranged alternately, and the packing 4 is separated by the gasket 3;

[0042] The gland 62 is pre-installed into the pipe socket 52, and the screw rod 73 passes through the connecting plate 72 and is placed beside the gland 62 to determine the fixed position of the screw rod 73;

[0043] The screw rod 73 is fixedly connected to the lower tube sheet 2;

[0044] The connecting plate 72 is fixedly connected to the gland 62;

[0045] The nut 71 and the screw rod 73 are screwed together, so that the nut 71 presses the connecting plate 72, and the position of the gland 62 in the axial direction A is adjusted by changing the position of the nut 71.

[0046] The pipe socket 52 is welded to the lower tube sheet 2, so it is difficult to ensure the position and posture of the pipe socket 52. Through the installation method of the above-mentioned packing seal structure, the fixed position of the screw rod 73 can be determined one by one according to the position of each pipe socket 52 in the vapor deposition furnace and the inclination degree of the pipe socket 52, so that the coaxiality between the pipe socket 52 and the gland 62 can be better controlled, and further ensure that the temperature difference stress and axial stress of the furnace tube 1 are uniform under high-temperature working conditions. When the furnace tube 1 expands, contracts and moves, the sealing performance between the furnace tube 1 and the pipe socket 52 is ensured, the furnace tube 1 is not damaged, the stable operation of the equipment is ensured, the replacement of the furnace tube and unnecessary shutdown maintenance are reduced, the production capacity of the equipment is effectively improved, and the economic benefits are improved.

[0047] It can be understood that the clearance fit between the gland 62 and the pipe socket 52 can better adjust the position and posture of the gland 62 to achieve the above effects.

[0048] In existing production practices, there are usually multiple furnace tubes (e.g., 90 tubes). If a threaded engagement gland and tube seat fitting method that requires precise fitting is adopted, special processing equipment and large-diameter high-precision inspection tools are needed. The thread processing technology is relatively complex and the cost is high. Welding and high temperatures can also affect the roundness and dimensions of the threads, and even cause thread deformation, which may lead to inability to assemble. The packing seal structure adopted in this application has simple processing and assembly of each component, reduces costs, saves time and effort, and is safe to operate.

[0049] The material of the furnace tube 1 of the chemical vapor deposition furnace can be Inconel 601 alloy. This alloy has the following characteristics: excellent oxidation resistance at high temperatures; good carburization resistance; can well resist sulfur-containing gas oxidation; has good mechanical properties at both room temperature and high temperatures; good stress corrosion cracking resistance. Due to the control of the carbon content and grain size, Inconel 601 alloy has a high creep rupture strength and is therefore suitable for use in environments above 500 °C. The heating temperature of the chemical vapor deposition furnace in this application can reach 700 °C.

[0050] Due to the better coaxiality of the gland and tube seat in this application, and the gland can adjust its position and posture to protect the furnace tube, the furnace tube in this application can withstand higher temperatures than the prior art, such as higher than 700 °C.

[0051] The above are the preferred embodiments of this application. It should be noted that for those skilled in the art, without departing from the principle of this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. An installation method of a stuffing box seal structure, characterized in that, The packing seal structure is the packing seal structure of a vapor deposition furnace. The vapor deposition furnace includes a furnace tube (1), a lower tube sheet (2), and a packing seal structure. The furnace tube (1) passes through the lower tube sheet (2), and the furnace tube (1) and the lower tube sheet (2) are sealed by the packing seal structure. The packing seal structure includes packing (4), a tube seat (52), a gland (62), and an ear structure (7). The tube seat (52) is welded to the lower tube sheet (2). The packing seal structure further includes a plurality of gaskets (3) disposed radially inside the tube seat (52). The ear structure (7) includes a nut (71), a connecting plate (72), and a screw (73). The connecting plate (72) is fixedly connected to the gland (62). The gland (62) is at least partially inserted into the tube seat (52) and presses one of the gaskets (3) against the lower tube sheet (2). The screw (73) can pass through the connecting plate (72). One end of the screw (73) is fixedly connected to the lower tube sheet (2). The screw (73) and the nut (71) are connected by a threaded fit. The position of the connecting plate (72) in the axial direction (A) of the screw (73) can be limited by the nut (71). The installation method of the packing seal structure includes: The gland (62) is pre-installed into the tube seat (52), and the screw (73) passes through the connecting plate (72) and is placed beside the gland (62) to determine the fixed position of the screw (73). The screw (73) is fixedly connected to the lower tube sheet (2) of the vapor deposition furnace. The connecting plate (72) is fixedly connected to the gland (62). The nut (71) and the screw (73) are screwed together, and the position of the gland (62) in the axial direction (A) is adjusted by changing the position of the nut (71).

2. The installation method of the stuffing box seal structure according to claim 1, characterized in that, The screw (73) is welded to the lower tube sheet (2).

3. The installation method of the packing seal structure according to claim 1, characterized in that The connecting plate (72) is welded to the gland (62).

4. The installation method of the packing seal structure according to claim 1, characterized in that The gland (62) has a clearance fit with the tube seat (52).

5. The installation method of the packing seal structure according to claim 1, characterized in that The packing seal structure includes multiple groups of the ear structures (7), and the position of the gland (62) in the axial direction (A) is adjusted by adjusting the positions of the multiple nuts (71) on their corresponding screws (73).

6. The installation method of the stuffing box seal structure according to claim 1, characterized in that The gland (62) and the tube seat (52) are coaxially arranged.

7. The installation method of the packing seal structure according to claim 1, characterized in that The connecting plate (72) has a hole, and the diameter of the hole is larger than the diameter of the screw (73), so that the screw (73) can displace and tilt relative to the connecting plate (72).

8. The installation method of the packing seal structure according to claim 1, characterized in that The stuffing box sealing structure includes multiple groups of the lug structures (7). By adjusting the positions of the nuts (71) of some of the lug structures (7) in the multiple groups of the lug structures (7) on the screw rods (73), the position and posture of the gland (62) are adjusted.

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