A method of installing a pressure vessel head

Abstract

The present application relates to pressure vessel installation technical field, specifically to a kind of pressure vessel top cover installation method.The present application provides a kind of pressure vessel top cover installation method, including the first positioning structure and the second positioning structure are assembled to the corresponding first positioning hole structure and the second positioning hole structure in cylinder flange, sealing ring is fixed into the sealing groove in the bottom end of top cover.In the process of top cover installation, since the second positioning structure is set first and the corresponding through-hole structure is aligned, the general orientation of the top cover is ensured not to be offset, the top cover is continued to fall, and the position of the top cover is further determined by the alignment of the first positioning structure and the groove structure, which can significantly reduce the adjustment frequency and time of the top cover during installation, thereby shortening the construction period of the top cover installed on the pressure vessel cylinder and improving the construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of pressure vessel installation technology, and more specifically to a method for installing a pressure vessel top cover. Background Technology

[0002] High-temperature gas-cooled reactors (HTGRs) are advanced nuclear energy technologies with independent intellectual property rights in my country, possessing fourth-generation technological characteristics. They have inherent safety features, wide application areas, and very broad commercial prospects. The HTGR pressure vessel is one of the core components of a nuclear power plant and a crucial element for the safe operation of the reactor. Its top cover installation is a challenging aspect of the construction process and a critical path affecting the overall construction progress of the nuclear power plant.

[0003] Currently, when hoisting the top cover onto the pressure vessel shell, the positioning accuracy of the top cover is required to be high. Traditional positioning methods require a lot of time to repeatedly adjust the position of the top cover, resulting in low construction efficiency. Summary of the Invention

[0004] (i) The problem to be solved by the present invention is that when the cylinder is hoisted onto the pressure vessel cylinder, the positioning accuracy of the top cover is required to be high. The traditional positioning method requires a lot of time to repeatedly adjust the position of the top cover, resulting in low construction efficiency.

[0005] (II) Technical Solution This invention provides a method for installing a pressure vessel top cover, used to install a top cover onto a pressure vessel shell. The top cover includes a top cover flange, and the pressure vessel shell includes a shell flange. The method includes the following steps: S1. Assemble the first positioning structure and the second positioning structure into the corresponding first positioning hole structure and second positioning hole structure on the cylindrical flange. S2. Fix the sealing ring into the sealing groove at the bottom of the top cover; S3. Hoist the top cover to the top of the pressure vessel body; S4. Lower the top cover, align the second positioning structure with the through hole structure on the top cover, continue to lower the top cover, align the first positioning structure with the groove structure on the top cover, and position the top cover onto the pressure vessel cylinder. S5. Remove the second positioning structure; S6. Secure the top cover to the pressure vessel body using multiple fasteners.

[0006] According to an embodiment of the present invention, step S1 specifically includes: The first positioning structure includes multiple positioning pins, and the first positioning hole structure includes multiple pin holes opened on the cylinder flange, with each positioning pin being inserted into the corresponding pin hole. The second positioning structure includes multiple guide rods, and the second positioning hole structure includes multiple threaded holes opened on the cylinder flange, with the multiple guide rods screwed into the corresponding threaded holes.

[0007] According to one embodiment of the present invention, between steps S2 and S3, the following step is further included: A guide positioning sleeve is fixed in each bolt hole opened on the top cover flange.

[0008] According to one embodiment of the present invention, a guide positioning sleeve is fixed in each bolt hole opened on the top cover flange, and the specific steps are as follows: The guide positioning sleeve is coaxially inserted into the corresponding bolt hole, and the end of the guide positioning sleeve is fixed to the top cover flange by fastening bolts.

[0009] According to one embodiment of the present invention, between steps S1 and S2, the following step is further included: Place a layer of rubber on the sealing surface of the cylinder flange.

[0010] According to an embodiment of the present invention, step S3 specifically comprises: Connect one end of the sling to the lifting lug on the top cover and the other end to the crane hook. After that, lift the top cover, adjust its level, and then hoist it onto the top of the pressure vessel cylinder.

[0011] According to an embodiment of the present invention, the through-hole structure in step S4 includes a plurality of bolt holes formed on the top cover flange, and the groove structure includes a plurality of circular grooves formed on the top cover flange. Step S4 specifically includes the following steps: S41. The top cover slowly descends, and the alignment of each guide rod with the bolt hole is checked. If there is any interference, the top cover is adjusted until each guide rod can be fully inserted into the bolt hole. S42. The top cover continues to fall slowly. When the positioning pin is about to enter the corresponding round groove, check the alignment between the positioning pin and the round groove. S43. The top cover continues to descend slowly until it is finally positioned on the flange of the cylinder.

[0012] According to an embodiment of the present invention, the through-hole structure in step S4 includes a plurality of central holes opened in the guide positioning sleeve, and the groove structure includes a plurality of circular grooves opened on the top cover flange. Step S4 specifically includes the following steps: S41. The top cover with the through hole structure falls slowly. Check the alignment of each guide rod with the center hole of the guide positioning sleeve. If there is any interference, adjust the top cover until each guide rod can be fully inserted into the center hole of the guide positioning sleeve. S42. The top cover continues to fall slowly. When the positioning pin is about to enter the corresponding circular groove, check the alignment between the positioning pin and the circular groove. S43. The top cover continues to fall slowly. When the conical part of the positioning pin enters the corresponding circular groove, the guide positioning sleeve is removed.

[0013] S44. Continue to slowly lower the top cover until it is finally in place on the flange of the pressure vessel body.

[0014] According to one embodiment of the present invention, between step S5 and step S6, the following step is further included: Double-check that the top cover axis corresponds to the pressure vessel cylinder axis.

[0015] According to an embodiment of the present invention, step S6 specifically includes: Fasteners include bolts, nuts, and washers. The bolts with nuts are passed through the washers and corresponding bolt holes in sequence and then screwed into the threaded holes.

[0016] The beneficial effects of this invention are: During the installation of the top cover, the second positioning structure is first aligned with the corresponding through hole structure to ensure that the approximate position of the top cover will not shift. The top cover continues to be lowered, and the position of the top cover is further determined by the alignment and cooperation of the first positioning structure and the groove structure. During the installation process, the number of adjustments to the top cover and the time required can be greatly reduced, thereby shortening the construction period for installing the top cover onto the pressure vessel cylinder and improving construction efficiency. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the top cover installation process provided in an embodiment of the present invention; Figure 2 A cross-sectional view of the top cover provided in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of the top cover flange, the cylindrical flange, the locating pin, the guide rod, and the guide locating sleeve provided in an embodiment of the present invention; Figure 4 This is a schematic diagram showing the connection between the guide positioning sleeve and the top cover flange provided in an embodiment of the present invention; Figure 5 This is a structural diagram of the positioning pin and the top cover provided in an embodiment of the present invention; Figure 6 This is a structural diagram of the top cover provided in an embodiment of the present invention.

[0019] Icons: 1. Top cover flange; 2. Cylinder flange; 3. Locating pin; 4. Guide rod; 5. Guide positioning sleeve; 6. Fastening bolt; 7. Lifting lug; 8. Circular groove; 9. Bolt hole; 10. First fuel loading / unloading nozzle; 11. Second fuel loading / unloading nozzle. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: like Figures 1-6 As shown, one embodiment of the present invention provides a method for installing a pressure vessel top cover, for installing a top cover onto a pressure vessel shell. The top cover includes a top cover flange 1, and the pressure vessel shell includes a shell flange 2. The method includes the following steps: S1. Assemble the first positioning structure and the second positioning structure into the corresponding first positioning hole structure and second positioning hole structure on the cylindrical flange 2. S2. Fix the sealing ring into the sealing groove at the bottom of the top cover; S3. Hoist the top cover to the top of the pressure vessel body; S4. Lower the top cover, align the second positioning structure with the through hole structure on the top cover, continue to lower the top cover, align the first positioning structure with the groove structure on the top cover, and position the top cover onto the pressure vessel cylinder. S5. Remove the second positioning structure; S6. Secure the top cover to the pressure vessel body using multiple fasteners.

[0022] Before the top cover is installed, a first positioning hole structure and a second positioning hole structure need to be opened on the cylinder flange 2, and the first positioning structure and the second positioning structure are respectively assembled into the corresponding first positioning hole structure and the second positioning hole structure. During the installation of the top cover, the second positioning structure is first aligned with the corresponding through hole structure to ensure that the approximate position of the top cover will not shift. The top cover continues to be lowered, and the position of the top cover is further determined by the alignment and cooperation of the first positioning structure and the groove structure. During the installation process, the number of adjustments to the top cover and the time required can be greatly reduced, thereby shortening the construction period for installing the top cover onto the pressure vessel cylinder and improving construction efficiency.

[0023] It should be noted that after the second positioning structure and the first positioning structure are assembled onto the cylindrical flange 2, the height of the second positioning structure is higher than that of the first positioning structure, and the second positioning structure enters the through hole structure first.

[0024] According to an embodiment of the present invention, step S1 specifically includes: The first positioning structure includes multiple positioning pins 3, and the first positioning hole structure includes multiple pin holes opened on the cylindrical flange 2, with each positioning pin 3 being inserted into the corresponding pin hole. The second positioning structure includes multiple guide rods 4, and the second positioning hole structure includes multiple threaded holes opened on the cylindrical flange 2, with one end of the multiple guide rods 4 screwed into the corresponding threaded holes.

[0025] During the process of hoisting the top cover onto the pressure vessel shell, centering adjustment is performed by setting guide rod 4 to ensure multi-point synchronization of hoisting, avoid the accumulation of single-point deviations, and reduce installation risks.

[0026] According to one embodiment of the present invention, between steps S1 and S2, the following step is further included: Place a layer of rubber on the sealing surface of the cylinder flange 2.

[0027] Confirm that there are no visible defects such as dents or scratches on the sealing surfaces of the pressure vessel body and top cover.

[0028] In step S2, the sealing ring is fixed into the sealing groove at the bottom of the top cover. Specifically, the cleanliness of the sealing ring is checked, and it is installed into the corresponding sealing groove at the bottom of the top cover. The sealing ring is fixed in the sealing groove by the fixing clip. After assembly, the sealing ring can be firmly fixed in the sealing groove, and the fixing clip is not higher than the top surface of the sealing groove. Tighten the screw torque to fix the fixing clip to the bottom of the top cover. After completion, remove the two tilted first fuel loading and unloading nozzle 10 end caps and temporarily protect them with wooden boards. Replacing them with wooden boards is beneficial for subsequent construction.

[0029] It should be noted that the top cover has structures such as a first fuel loading and unloading nozzle 10, a second fuel loading and unloading nozzle 11, a manhole nozzle, a material irradiation monitoring nozzle, and a neutron source nozzle. This is existing technology and will not be described in detail.

[0030] According to an embodiment of the present invention, step S3 specifically includes: Connect one end of the sling to the lifting lug 7 on the top cover and the other end to the crane hook. After completion, lift the top cover, adjust its level, and then hoist it to the top of the pressure vessel cylinder.

[0031] Multiple lifting lugs 7 are spaced apart along the circumference of the top cover, and all are connected to the crane hook via slings.

[0032] According to an embodiment of the present invention, when the through-hole structure includes a plurality of bolt holes 9 formed on the top cover flange 1, and the groove structure includes a plurality of circular grooves 8 formed on the top cover flange 1, step S4 specifically includes the following steps: S41. Use a crane to slowly lower the top cover and check the alignment of each guide rod 4 with the bolt hole 9. If there is any interference, adjust the top cover until each guide rod 4 can be fully inserted into the bolt hole 9. S42. The top cover continues to fall slowly. When the positioning pin 3 is about to enter the corresponding circular groove 8, check the alignment of the positioning pin 3 and the circular groove 8. If they are not aligned, adjust them until they are aligned. S43. The top cover continues to descend slowly until it is finally positioned on the flange of the cylinder.

[0033] It should be noted that the bolt holes 9 and guide rods 4 are set one-to-one, and the circular grooves and positioning pins 3 are set one-to-one. Preferably, there are four guide rods 4 and four positioning pins 3.

[0034] According to one embodiment of the present invention, when the step S2 and S3 are combined, the following step is further included: A guide positioning sleeve 5 is fixed in each bolt hole 9 opened on the top cover flange 1. Specifically, the sleeve body of the guide positioning sleeve 5 is coaxially inserted into the corresponding bolt hole 9, and the end of the guide positioning sleeve 5 is fixed to the top cover flange 1 by fastening bolts 6.

[0035] Compared to the guide rod 4 directly contacting the bolt hole 9, the guide positioning sleeve 5 is designed and installed to serve as a limit mark for the top cover to be in place, and at the same time reduce the friction between the bolt hole 9 and the guide rod 4 during the falling of the top cover, thus reducing wear on the main body.

[0036] Correspondingly, the through-hole structure includes multiple central holes opened within the guide positioning sleeves 5, and the groove structure includes multiple circular grooves 8 opened on the top cover flange 1. Therefore, step S4 changes compared to not using the positioning guide sleeves, specifically including the following steps: S41. Use a crane to slowly lower the top cover and check the alignment of each guide rod 4 with the center hole of the guide positioning sleeve 5. If there is any interference, adjust the top cover until each guide rod 4 can be fully inserted into the center hole of the guide positioning sleeve 5. S42. The top cover continues to fall slowly. When the positioning pin 3 is about to enter the corresponding circular groove 8, check the alignment of the positioning pin 3 and the circular groove 8. If they are not aligned, make adjustments until they are aligned. S43. The top cover continues to fall slowly. When the cone-shaped part of the positioning pin 3 enters the corresponding circular groove 8, the guide positioning sleeve 5 is removed.

[0037] S44. Continue to slowly lower the top cover until it is finally in place on the flange of the pressure vessel body.

[0038] It should be noted that the bolt holes 9, guide positioning sleeves 5, and guide rods 4 are set in a one-to-one correspondence, and the circular grooves and positioning pins 3 are set in a one-to-one correspondence. Preferably, there are four guide rods 4 and four positioning pins 3.

[0039] According to one embodiment of the present invention, between step S5 and step S6, the following step is further included: Double-check that the top cover axis corresponds to the pressure vessel cylinder axis.

[0040] According to one embodiment of the present invention, in step S5, the second positioning structure is removed, that is, the other end of the guide rod 4 located on the upper side of the top cover flange 1 is held by a tool or by hand, and the other end of the guide rod 4 is screwed out from the corresponding threaded hole.

[0041] According to an embodiment of the present invention, step S6 specifically includes: Fasteners include bolts, nuts, and washers. The bolts with nuts are passed through the washers and the corresponding bolt holes 9 in sequence and then screwed into the threaded holes.

[0042] In practical use, bolts and nuts can be assembled in advance, reducing on-site assembly time and thus shortening the construction period.

[0043] Preferably, both the pin hole and the threaded hole are blind holes.

[0044] In the description of this invention, it should be noted that the terms "upper" and "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for installing a pressure vessel top cover, used to install a top cover onto a pressure vessel shell, the top cover including a top cover flange (1), and the pressure vessel shell including a shell flange (2), characterized in that, Includes the following steps: S1. Assemble the first positioning structure and the second positioning structure into the corresponding first positioning hole structure and the second positioning hole structure on the cylindrical flange (2); S2. Fix the sealing ring into the sealing groove at the bottom of the top cover; S3. Hoist the top cover to the top of the pressure vessel body; S4. Lower the top cover, align the second positioning structure with the through hole structure on the top cover, continue to lower the top cover, align the first positioning structure with the groove structure on the top cover, and position the top cover onto the pressure vessel cylinder. S5. Remove the second positioning structure; S6. Secure the top cover to the pressure vessel body using multiple fasteners.

2. The method for installing a pressure vessel top cover according to claim 1, characterized in that, The S1 step specifically includes: The first positioning structure includes multiple positioning pins (3), and the first positioning hole structure includes multiple pin holes opened on the cylindrical flange (2), and each positioning pin (3) is inserted into the corresponding pin hole; The second positioning structure includes multiple guide rods (4), and the second positioning hole structure includes multiple threaded holes opened on the cylindrical flange (2), and the multiple guide rods (4) are screwed into the corresponding threaded holes.

3. The method for installing a pressure vessel top cover according to claim 2, characterized in that, Between steps S2 and S3, the following steps are also included: A guide positioning sleeve (5) is fixed in each bolt hole (9) opened on the top cover flange (1).

4. The method for installing a pressure vessel top cover according to claim 3, characterized in that, A guide positioning sleeve (5) is fixed in each bolt hole (9) opened on the top cover flange (1). The specific steps are as follows: The sleeve of the guide positioning sleeve (5) is coaxially inserted into the corresponding bolt hole (9), and the end of the guide positioning sleeve (5) is fixed to the top cover flange (1) by fastening bolts (6).

5. The method for installing a pressure vessel top cover according to claim 1, characterized in that, Between steps S1 and S2, the following steps are also included: Place a layer of rubber on the sealing surface of the cylindrical flange (2).

6. The method for installing a pressure vessel top cover according to claim 1, characterized in that, The S3 step specifically includes: Connect one end of the sling to the lifting lug (7) on the top cover and the other end to the crane hook. After completion, lift the top cover, adjust its level, and then hoist it to the top of the pressure vessel cylinder.

7. The method for installing a pressure vessel top cover according to claim 2, characterized in that, The through-hole structure in step S4 includes multiple bolt holes (9) opened on the top cover flange (1), and the groove structure includes multiple circular grooves (8) opened on the top cover flange (1). Step S4 specifically includes the following steps: S41. The top cover slowly falls down. Check the alignment of each guide rod (4) with the bolt hole (9). If there is any interference, adjust the top cover until each guide rod (4) can be fully inserted into the bolt hole (9). S42. The top cover continues to fall slowly. When the positioning pin (3) is about to enter the corresponding circular groove (8), check the alignment of the positioning pin (3) and the circular groove (8). S43. The top cover continues to descend slowly until it is finally positioned on the flange of the cylinder.

8. A method for installing a pressure vessel top cover according to claim 3, characterized in that, The through-hole structure in step S4 includes a central hole opened in a plurality of guide positioning sleeves (5), and the groove structure includes a plurality of circular grooves (8) opened on the top cover flange (1). Step S4 specifically includes the following steps: S41. The top cover with the through hole structure falls slowly. Check the alignment of each guide rod (4) with the center hole of the guide positioning sleeve (5). If there is any interference, adjust the top cover until each guide rod (4) can be fully inserted into the center hole of the guide positioning sleeve (5). S42. The top cover continues to fall slowly. When the positioning pin (3) is about to enter the corresponding circular groove (8) on the top, check the alignment of the positioning pin (3) and the circular groove (8). S43. The top cover continues to fall slowly. When the cone-shaped part of the positioning pin (3) enters the corresponding circular groove (8), the guide positioning sleeve (5) is removed. S44. Continue to slowly lower the top cover until it is finally in place on the flange of the pressure vessel body.

9. A method for installing a pressure vessel top cover according to claim 1, characterized in that, Between step S5 and step S6, the following steps are also included: Double-check that the top cover axis corresponds to the pressure vessel cylinder axis.

10. A method for installing a pressure vessel top cover according to claim 1, characterized in that, The S6 step is specifically as follows: Fasteners include bolts, nuts and washers. The bolts with nuts are passed through the washers and the corresponding bolt holes (9) in sequence and then screwed into the threaded holes.

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