A construction accuracy control method for the cargo tank compartment of a gas carrier

Abstract

The present invention relates to the technical field of shipbuilding, and discloses a method for controlling the construction accuracy of a cargo tank compartment of a gas carrier, including setting a reference line for the cargo tank compartment; structural cutting design; when the span of a single cargo tank is less than or equal to four circumferential closing joints, adding operation allowances only at one circumferential closing joint of the cargo tank compartment; when the span of a single cargo tank along the length direction of the gas carrier is greater than four circumferential closing joints, adding operation allowances at two circumferential closing joints of the cargo tank compartment respectively; determining the extension value added in the length direction of the entire cargo tank compartment; adding closing welding compensation amounts at the stern openings of each section of the cargo tank compartment; constructing the cargo tank compartment in sections; respectively constructing the bottom section, the lower side section and the upper side section; sectional general assembly; respectively carrying out the ground general assembly of the bottom section and the ground general assembly of the side section; hoisting the cargo tank compartment; the present invention solves the problem of the installation accuracy of the cargo tank of the gas carrier by controlling the length accuracy of the cargo tank compartment of the gas carrier.

Description

Technical Field

[0001] The present invention relates to the technical field of shipbuilding, and particularly to a method for controlling the construction accuracy of a cargo tank hold of a gas carrier ship. Background Art

[0002] The sectional area of the cargo tank hold of a gas carrier ship is provided with cargo tank saddles, deck tank saddles, anti-floating structures, convex decks, etc., and its accuracy requirements are relatively high. The cargo tank saddles are related to the matching with the cargo tanks. Each cargo tank is to be placed on two saddles, the front and the rear, and the front and rear saddles are not on the same section. It is necessary to control the front and rear deviations of the saddles during the sectional stage and the general assembly and erection stage to ensure the matching with the cargo tanks. For the length values of the webs of the bow and stern saddles of the same cargo tank, the tolerance requirements are high, the process tolerance is 0 mm to +8 mm, and the final tolerance after welding is -3 mm to +5 mm; and the length of the saddle on the side shell section should correspond to the length of the saddle on the bottom section, and the deviation value between the two should not exceed 5 mm.

[0003] If the existing shipbuilding techniques and methods are adopted, operation allowances need to be added to each section in the cargo hold area. When it comes to general assembly or erection, the saddle lengths between the sections are measured on-site and then the allowances are cut. According to this approach, the non-allowance rate of shipbuilding will decrease significantly, and during the general assembly and erection of the sections, allowance cutting is required, which takes a long positioning time, occupies a lot of crane resources, is time-consuming and laborious, and greatly increases the construction cost. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the construction accuracy of a cargo tank hold of a gas carrier ship, and by controlling the length accuracy of the cargo tank hold of the gas carrier ship, to solve the problem of the installation accuracy of the cargo tanks of the gas carrier ship.

[0005] To achieve the above purpose, the present invention provides a method for controlling the construction accuracy of a cargo tank hold of a gas carrier ship, including the following steps:

[0006] Step 1, set the reference line of the cargo tank hold;

[0007] Step 2, structural cutting design;

[0008] The shrinkage data of the longitudinal girders, longitudinal trusses and floors to the main plate after welding are obtained through welding tests, and the shrinkage data of the longitudinal girders, longitudinal trusses and floors to the main plate after heat treatment adjustment are obtained through heat treatment adjustment tests, so as to determine the extension values added in the length direction of the entire cargo tank hold; when the span of a single cargo tank along the length direction of the gas carrier is less than or equal to four circumferential closing joints, an operation margin is added only at one circumferential closing joint of the cargo tank hold; when the span of a single cargo tank along the length direction of the gas carrier is greater than four circumferential closing joints, operation margins are added at two circumferential closing joints of the cargo tank hold respectively, and the two circumferential closing joints are not adjacent in the length direction of the cargo tank hold along the gas carrier; among them, the circumferential closing joint includes a bottom section closing joint and a side shell section closing joint in the same cross section in the cargo tank hold; a closing welding compensation amount is added at the stern or bow opening of each section of the cargo tank hold;

[0009] Step 3, sectional construction of the cargo tank hold; construct the bottom section, the lower side shell section and the upper side shell section respectively;

[0010] Step 4, sectional assembly; perform ground assembly of the bottom section and ground assembly of the side shell section respectively;

[0011] 4.1. Ground assembly of the bottom section, perform ground assembly of each bottom section to form a bottom sub-assembly;

[0012] 4.2. Side shell section assembly, the side shell section assembly includes upper and lower side shell section assembly and front and rear side shell section assembly; first, perform upper and lower assembly of the lower side shell section and the upper side shell section on the jig with the outer plate as the base surface to form side shell sections respectively, and then perform front and rear assembly of each side shell section to form a side shell sub-assembly;

[0013] Among them, the order of step 4.1 and step 4.2 is not in sequence;

[0014] Step 5, erection of the cargo tank hold, adjust the positioning accuracy of the bottom sub-assembly and the side shell sub-assembly.

[0015] As a preferred solution of the present invention, in the said step 3, the bottom section is constructed with the outer plate of the bottom section as the base surface; the lower side shell section is constructed with the inclined wall of the lower side shell section as the base surface; the upper side shell section is constructed with the outer plate of the upper side shell section as the base surface.

[0016] As a preferred solution of the present invention, in the said step 4.1, when controlling the accuracy in the length direction, by measuring and adjusting the length between the rib position inspection lines and the rib pitch at the closing joint, control the distance between the two saddles at the bow and stern of the bottom sub-assembly to be a preset value, so that the process tolerance of the length of the two saddles at the bow and stern before welding of the bottom sub-assembly is within 0 mm to +8 mm, and the tolerance after welding is within -3 mm to +5 mm;

[0017] When controlling the level accuracy, by measuring and adjusting the relative height values of the two saddles at the bow and stern of the bottom sub-assembly, and making the four corners of the upper mouth of the saddle web horizontal, and taking the measuring points on the T-beam panel near the saddle as reference points, control the level deviation of the bottom sub-assembly ≤ 8 mm;

[0018] When controlling the center line accuracy, control the deviation between the bow and stern center lines of the bottom sub-assembly and the preset center line ≤ 3 mm, and at the same time control the flatness deviation of the closing openings on the left and right sides of the bottom sub-assembly ≤ 5 mm.

[0019] As a preferred solution of the present invention, in the step 4.2, when controlling the accuracy of the overall assembly of the upper and lower side shell sub-assemblies, control the longitudinal wall level deviation of the side shell sub-assembly ≤ 8 mm, and add horizontal measuring points at the saddle position of the side shell sub-assembly as reference points; control the relative height value from the main deck of the side shell sub-assembly to the hull baseline within 0 mm to 5 mm, and add height measuring points at the anti-floating structure position of the side shell sub-assembly as reference points; measure the rib position inspection lines of the lower side shell sub-assembly and the upper side shell sub-assembly, make the rib position inspection lines of the lower side shell sub-assembly and the upper side shell sub-assembly in the same plane, control the deviation between the rib position inspection lines of the lower side shell sub-assembly and the upper side shell sub-assembly within ±2 mm, and control the front and rear deviation of the saddle web within ±2 mm.

[0020] As a preferred solution of the present invention, in the step 4.2, when controlling the accuracy of the overall assembly of the front and rear side shell sub-assemblies, measure the flatness of the longitudinal wall of the side shell sub-assembly, control the overall longitudinal wall level deviation of the side shell sub-assembly ≤ 8 mm, and control the straightness deviation of the main deck of the side shell sub-assembly ≤ 8 mm; control the overall level deviation of the T-beam panel of the side shell sub-assembly ≤ 8 mm, and the flatness deviation of the closing openings around the side shell sub-assembly ≤ 5 mm; measure the length between the rib position inspection lines of the side shell sub-assembly and the total length of the side shell sub-assembly, so that the process tolerance of the length of the two saddles at the bow and stern before welding of the side shell sub-assembly is within 0 mm to +8 mm, and the tolerance after welding is within -3 mm to +5 mm; and control the deviation between the length between the two saddles at the bow and stern of the side shell sub-assembly and the length between the two saddles at the bow and stern of the bottom sub-assembly ≤ 5 mm.

[0021] As a preferred solution of the present invention, in the step 5, when controlling the erection and positioning accuracy of the bottom sub-assembly,

[0022] In the control of level accuracy, measure the level of the bottom sub-assembly, additionally measure the level near the saddle, control the level deviation of the entire bottom sub-assembly ≤ 8 mm, and additionally measure the height value of the saddle web to ensure it is the same as the preset value;

[0023] In the control of center line accuracy, control the deviation between the center line of the bottom sub-assembly and the ground sample center line ≤ 3 mm, and measure and control the flatness deviation of the bow and stern openings of the sub-assembly ≤ 5 mm;

[0024] In the control of length accuracy, control the length deviation of the rib spacing at each closing joint of the bottom total section within 0 mm to +5 mm, and measure the length between the inspection line of each rib position and the saddle web to ensure it is the same as the preset value.

[0025] As a preferred solution of the present invention, in step 5, when controlling the positioning accuracy of the side shell total section during the accuracy control in the half-width direction, measure the half-width of the upper and lower openings of the side shell total section, and control the half-width deviation of the upper and lower openings of the inner longitudinal wall of the side shell total section within 0 mm to +5 mm;

[0026] In the height direction accuracy control, measure the height at the main deck of the side shell total section and the height at the anti-floating block of the side shell total section, and control the mounting and positioning height deviation of the side shell total section within 0 mm to +5 mm;

[0027] In the length direction accuracy control, measure the rib inspection line of the side shell total section and the saddle web of the side shell total section, and control the front and rear deviation of the saddle of the side shell total section and the saddle web of the bottom total section within 0 mm to +5 mm;

[0028] When installing the bulk anti-floating structure, measure and control the gap between the anti-floating wooden blocks of the cargo tank and the anti-floating structure backing plate, and control the deviation of the bulk anti-floating structure within ±5 mm in the up and down direction, within ±5 mm in the left and right direction, and within ±5 mm in the front and rear direction.

[0029] As a preferred solution of the present invention, in step 2, the operating allowance added at the annular closing joint is 20 mm.

[0030] As a preferred solution of the present invention, in step 2, the extension value is 0.3 mm / rib position.

[0031] As a preferred solution of the present invention, in step 2, the closing welding compensation amount added at the stern or bow of each section of the cargo tank is 4 mm.

[0032] As a preferred solution of the present invention, in step 3, control the tolerance of the bottom section within ±5 mm in length, within ±5 mm in width, within ±5 mm in height, and within ≤8 mm in flatness;

[0033] Control the tolerance of the lower side shell section within ±5 mm in length, within ±5 mm in width, within ±5 mm in height, and within ≤8 mm in flatness;

[0034] Control the tolerance of the upper side shell section within ±5 mm in length, within ±5 mm in width, within ±5 mm in height, and within ≤8 mm in flatness.

[0035] Compared with the prior art, the beneficial effect of the construction accuracy control method for the cargo tank hold of a gas carrier in an embodiment of the present invention lies in that:

[0036] Through the preliminary scheme design, the present invention sets the reference line during the sectional construction process, and determines the number of additional annular closure openings according to the number of cargo tanks straddling the annular closure opening. The shipbuilding non-surplus rate is such that there is no need for surplus cutting during the sectional assembly and erection, and the surplus, extension value, and closure welding compensation amount of the annular closure opening are reasonably added. Moreover, the process control during the sectional construction process and the process control during the sectional assembly and erection are carried out to ensure that the tolerances of the bow and stern saddles of a single cargo tank meet the accuracy requirements, achieving one-time completion of the cargo tank hoisting, reducing rework, improving the construction efficiency, and reducing the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below.

[0038] Figure 1 is a schematic structural diagram of the bottom section provided by the present invention;

[0039] Figure 2 is a schematic structural diagram of the lower side section in the state of not installing the outer plate on the jig provided by the present invention;

[0040] Figure 3 is a schematic structural diagram of the lower side section after turning over provided by the present invention;

[0041] Figure 4 is an exploded view of the upper side section provided by the present invention;

[0042] Figure 5 is a schematic structural diagram of the upper side section provided by the present invention;

[0043] Figure 6 is a schematic structural diagram of the bottom sub-assembly provided by the present invention;

[0044] Figure 7 is a schematic structural diagram of multiple connected lower side sections provided by the present invention;

[0045] Figure 8 is a schematic structural diagram of the side section provided by the present invention;

[0046] In the figure, 1 is the bottom segment; 11 is the outer plate of the bottom segment; 12 is the longitudinal and transverse T-beam structure of the bottom segment; 13 is the transverse rib plate of the bottom segment; 14 is the small box structure at both ends of the saddle of the bottom segment; 15 is the structural patch plate part of the bottom segment; 16 is the saddle of the bottom segment; 2 is the lower side segment; 21 is the prefabricated middle component of the inclined longitudinal wall of the lower side segment; 22 is the rib plate of the lower side segment; 23 is the prefabricated middle component of the platform of the lower side segment; 24 is the outer plate of the lower side segment; 25 is the saddle part structure of the lower side segment; 3 is the upper side segment; 31 is the outer plate of the upper side segment; 32 is the prefabricated small component of the transverse rib plate of the upper side segment; 33 is the prefabricated small component of the longitudinal wall plate of the upper side segment; 34 is the prefabricated small component of the platform plate of the upper side segment; 35 is the prefabricated small component of the transverse rib plate of the upper side segment; 36 is the prefabricated middle component of the main deck of the upper side segment; 37 is the prefabricated middle component of the longitudinal wall plate and stiffener of the upper side segment. Detailed implementation manners

[0047] The following combines the drawings and embodiments to further describe in detail the detailed implementation manners of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0048] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0049] As Figures 1 to 8 shown, a method for controlling the construction accuracy of a cargo tank compartment of a gas carrier in a preferred embodiment of the present invention includes the following steps:

[0050] Step 1: Set the reference line of the cargo tank compartment;

[0051] Step 2: Structural cutting stock design;

[0052] In order to offset the welding shrinkage and thermal straightening shrinkage during the sectional construction process, the welding shrinkage data of the longitudinal frames, longitudinal girders and floors to the main plate after welding are obtained through welding tests, and the thermal straightening shrinkage data of the longitudinal frames, longitudinal girders and floors to the main plate after thermal straightening are obtained through thermal straightening tests, so as to determine the elongation values added in the length direction of the entire cargo tank hold; when the span of a single cargo tank along the length direction of the gas carrier is less than or equal to four ring joint openings, operation allowances are added only at one ring joint opening of the cargo tank hold; when the span of a single cargo tank along the length direction of the gas carrier is greater than four ring joint openings, operation allowances are added at two ring joint openings of the cargo tank hold respectively, and the two ring joint openings are not adjacent to each other along the length direction of the cargo tank hold of the gas carrier; among them, the ring joint openings include the bottom sectional joint opening and the side sectional joint opening in the same cross-section in the cargo tank hold; in order to offset the welding shrinkage problem of the entire ring joint opening during the sectional assembling and erection process, closing welding compensation amounts are added at the stern openings of each section (i.e., each bottom section, each lower side section and each upper side section) of the cargo tank hold. Of course, closing welding compensation amounts can also be added at the bow openings of each section (i.e., each bottom section, each lower side section and each upper side section) of the cargo tank hold.

[0053] Step 3: Sectional construction of the cargo tank hold; construct the bottom section, the lower side section and the upper side section separately.

[0054] Step 4: Sectional assembling; conduct the ground assembling of the bottom section and the ground assembling of the side section separately.

[0055] 4.1 Ground assembling of the bottom section: Assemble each bottom section on the ground to form the bottom total section.

[0056] 4.2 Side section assembling: The side section assembling includes the upper and lower side section assembling and the front and rear side section assembling; first, assemble the lower side section and the upper side section on the jig with the outer plate as the base surface for upper and lower assembling to form the side sections respectively, and then assemble each side section for front and rear assembling to form the side total sections (the left side total section and the right side total section).

[0057] Among them, the order of step 4.1 and step 4.2 is not in sequence.

[0058] Step 5: Erection of the cargo tank hold; adjust the positioning accuracy of the bottom total section and the side total section.

[0059] Exemplarily, in step 4.1, when controlling the accuracy in the length direction, by measuring and adjusting the length between the rib position inspection lines and the rib distance at the butt joint, specifically using a total station to measure the distance between the rib position inspection lines at the bottom section, the rib distance at the bottom section butt joint, and the distance at the saddle center line, the distance between the bow and stern saddles of the bottom assembly is controlled to be a preset value. Specifically, measure the distance between the bow and stern saddles of the bottom assembly along the left side of the bottom assembly, measure the distance between the bow and stern saddles of the bottom assembly along the right side of the bottom assembly, and measure the distance between the bow and stern saddles of the bottom assembly along the center line of the bottom assembly. This ensures the accuracy of the measured distance between the bow and stern saddles of the bottom assembly, such that the process tolerance of the length of the bow and stern saddles before welding of the bottom assembly is within 0 mm to +8 mm, and the tolerance after welding is within -3 mm to +5 mm;

[0060] When controlling the level accuracy, by measuring and adjusting the relative height values of the bow and stern saddles of the bottom assembly, and making the four corners of the upper mouth of the saddle web horizontal, and using the measurement points near the T-beam panel of the saddle as reference points, the level deviation of the bottom assembly is controlled to be ≤8 mm; the specific operation is as follows: Place the bottom assembly on the gantry bench, set one of the bottom sections in the bottom assembly as the reference section. Thus, the bottom assembly uses this reference section bottom section as a reference to level the reference point (the double-circle position in the figure) of this reference section. Use a laser theodolite or a total station to measure its levelness.

[0061] When controlling the center line accuracy, control the deviation between the bow and stern center lines of the bottom assembly and the preset center line to be ≤3 mm, and at the same time control the flatness deviation of the butt joints on the left and right sides of the bottom assembly to be ≤5 mm. The specific operation is as follows: Set one of the bottom sections in the bottom assembly as the reference section. Thus, the bottom assembly uses this reference section bottom section as a reference, and use a total station to measure the deviation between the center line of the entire bottom assembly and the center line of the reference section; ensure high accuracy of the bottom assembly after the ground total assembly of the bottom section is completed, and ensure the accurate position of the bow and stern saddles;

[0062] Exemplarily, in step 4.2, when controlling the precision of the overall assembly of the upper and lower side shell sections, control the horizontal deviation of the longitudinal wall of the side shell section to be ≤8 mm, and add horizontal measurement points at the saddle positions of the side shell section as reference points; control the relative height value from the main deck of the side shell section to the hull baseline to be within 0 mm to 5 mm, and add height measurement points at the buoyancy prevention structure positions of the side shell section as reference points; measure the rib inspection lines of the lower side shell section and the upper side shell section, so that the rib inspection lines of the lower side shell section and the upper side shell section are in the same plane, control the deviation between the rib inspection lines of the lower side shell section and the upper side shell section to be within ±2 mm, and control the front and rear deviation of the saddle web to be within ±2 mm. Specifically, measure the front and rear deviation values of the saddle web at the upper part of the saddle web, measure the front and rear deviation values of the saddle web in the middle of the saddle web, and measure the front and rear deviation values of the saddle web at the lower part of the saddle web, so as to ensure the accuracy of the data of the saddle web of the side shell section measured. Specifically, it can be measured by a laser theodolite or a total station, ensuring high precision of the side shell section after the overall assembly of the upper and lower side shell sections.

[0063] Exemplarily, in step 4.2, when controlling the precision of the overall assembly of the front and rear side shell sections, measure the flatness of the longitudinal wall of the side shell section as a whole, control the overall horizontal deviation of the longitudinal wall of the side shell section to be ≤8 mm, and control the straightness deviation of the main deck of the side shell section to be ≤8 mm; control the overall horizontal deviation of the T-beam panel of the side shell section to be ≤8 mm, and the alignment deviation of the butt joints around the side shell section to be ≤5 mm. The specific operation is as follows: Place the side shell section on the gantry bench, set one of the side shell sections in the side shell section as the reference section, so that the side shell section is based on this reference side shell section, level the reference points (the double-circle positions in the figure) of this reference section, and measure its levelness by a laser theodolite or a total station; measure the flatness of the deck surface of the side shell section and the alignment at the butt joint of the side shell section by a total station; measure the length between the rib inspection lines of the side shell section as a whole and the total length of the side shell section as a whole by a total station, so that the process tolerance of the length of the two saddle seats at the bow and stern before welding is within 0 mm to +8 mm, and the tolerance after welding is within -3 mm to +5 mm; and control the length deviation between the two saddle seats at the bow and stern of the side shell section as a whole and the length between the two saddle seats at the bow and stern of the bottom section to be ≤5 mm.

[0064] Specifically, it can be measured by a laser theodolite or a total station, ensuring high precision of the side shell section as a whole after the overall assembly of the front and rear side shell sections, and ensuring the accurate positions of the bow and stern saddle seats.

[0065] Exemplarily, in step 5, when controlling the positioning precision of the bottom section during mating and installation,

[0066] In the horizontal accuracy control, measure the levelness of the bottom total section, additionally measure the levelness near the saddle, control the levelness deviation of the entire bottom total section ≤ 8 mm, and additionally measure the height value of the saddle web to ensure it is the same as the preset value;

[0067] In the center line accuracy control, control the deviation between the center line of the bottom total section and the ground sample center line ≤ 3 mm, and measure and control the flushness deviation of the bow and stern openings of the section ≤ 5 mm;

[0068] In the length accuracy control, control the rib spacing length deviation of each joint of the bottom total section within 0 mm to +5 mm, and measure the length between the inspection lines of each rib position and the saddle web to ensure it is the same as the preset value.

[0069] Exemplarily, in step 5, when controlling the erection and positioning accuracy of the side shell total section,

[0070] In the half-width direction accuracy control, measure the half-width of the upper and lower openings of the side shell total section, and control the half-width deviation of the upper and lower openings of the inner longitudinal wall of the side shell total section within 0 mm to +5 mm;

[0071] In the height direction accuracy control, measure the height at the main deck of the side shell total section and the height at the anti-floating block of the side shell total section, and control the erection and positioning height deviation of the side shell total section within 0 mm to +5 mm;

[0072] In the length direction accuracy control, measure the rib inspection line of the side shell total section and the saddle web of the side shell total section, and control the front and rear deviation between the saddle of the side shell total section and the saddle web of the bottom total section within 0 mm to +5 mm;

[0073] When installing the bulk anti-floating structure, measure and control the gap between the anti-floating wooden blocks of the cargo tank and the anti-floating structure backing plates, control the deviation of the bulk anti-floating structure in the up and down direction within ±5 mm, in the left and right direction within ±5 mm, and in the front and rear direction within ±5 mm, ensure that the saddle accuracy matches well with the laminated wood line of the cargo tank, and the tank dropping time can be controlled within 1 hour to complete (including the epoxy pouring process), without any rework or repair situations;

[0074] As the last process to control the overall length of the cargo tank hold, erection must be carried out strictly in accordance with the construction process to ensure that the overall length of the cargo tank meets the requirements after section erection, and the length of the stern saddle of the same cargo tank is within the tolerance range.

[0075] Exemplarily, in the step 2, the operating allowance added at the annular closing opening is 20 mm. In this embodiment, a single cargo tank spans three annular closing openings along the length direction of the gas carrier. Therefore, only 20 mm of allowance is added at one annular closing opening of the cargo tank compartment, that is, 20 mm of allowance is added to the entire annular closing opening of the stern opening of the bottom section, the stern opening of the lower side shell section, and the stern opening of the upper side shell section (of course, 20 mm of allowance can also be added to the entire annular closing opening of the bow opening of the bottom section, the bow opening of the lower side shell section, and the bow opening of the upper side shell section).

[0076] Exemplarily, in the step 2, in order to offset the welding shrinkage and heat treatment shrinkage during the sectional construction, an elongation value is added to the entire length direction of the cargo hold. The elongation value is 0.3 mm / frame. Through the collection and research of welding shrinkage and heat treatment shrinkage data, the shrinkage amount of the longitudinal girder / longitudinal truss on the main plate is 0.1 mm / m, and the shrinkage amount of the floor plate on the main plate is 0.2 mm / space. Therefore, the elongation value to be added per FR (hull frame) = (section length x 0.1 mm / m + number of floor plate spaces x 0.2 mm / space) / total number of frames. After calculation and rounding for this ship, it is 0.3 mm / frame.

[0077] Exemplarily, in the step 2, in order to offset the welding shrinkage problem of the entire annular closing opening during the sectional assembly and erection, through data research, it is found that the shrinkage amount at each closing opening varies according to the plate thickness. The specific shrinkage data is shown in the following table:

[0078]

[0079] In order to better ensure the positive tolerance of the entire closing, therefore, the closing welding compensation amount added at the stern opening or bow opening of each section of the cargo tank compartment is 4 mm as the welding shrinkage compensation.

[0080] Exemplarily, in the step 3

[0081] When constructing the bottom section, the bottom section is constructed with the outer plate of the bottom section as the base surface, and all structures are installed according to the reference line. The specific installation is as follows:

[0082] (1) The longitudinal girders and the outer plate 11 are prefabricated and assembled onto the jig;

[0083] (2) The longitudinal and transverse T-beam structures 12 are assembled in small groups and then assembled onto the jig for medium assembly;

[0084] (3) The saddle pressing wood groove lower support transverse floor plate 13 is installed;

[0085] (4) The small box-type structures 14 at both ends of the saddle are installed;

[0086] (5) Other small T-section structures are assembled in small groups and then installed onto the jig, and the structural patch plates 15 are installed onto the jig;

[0087] (6) Saddle 16, for bulk loading;

[0088] Among them, the tolerances of the bottom segment in terms of length are within ±5 mm, in terms of width are within ±5 mm, in terms of height are within ±5 mm, and in terms of flatness are within ≤8 mm.

[0089] In the said step 3, when constructing the lower side segment, the lower side segment is constructed with the inclined wall of the lower side segment as the base surface, and all structures are installed according to the reference line. The specific installation is as follows:

[0090] (1) Prefabricated intermediate component 21 of the inclined longitudinal wall, used as the jig plate;

[0091] (2) Bulky installation of the rib plate 22;

[0092] (3) Installation of the prefabricated intermediate component 23 of the platform;

[0093] (4) Bulky installation of the outer plate 24;

[0094] (5) Structure 25 of the saddle part after the segment is turned over (the cargo tank pressing groove structure is installed after the overall assembly with the upper side segment);

[0095] Among them, the tolerances of the lower side segment in terms of length are within ±5 mm, in terms of width are within ±5 mm, in terms of height are within ±5 mm, and in terms of flatness are within ≤8 mm.

[0096] In the said step 3, when constructing the upper side segment, the upper side segment is constructed with the outer plate of the upper side segment as the base surface, and all structures are installed according to the reference line. The specific installation is as follows:

[0097] (1) The outer plate 31 and the stiffeners are placed on the jig plate of the prefabricated intermediate assembly jig;

[0098] (2) Installation of the prefabricated small component 32 of the transverse rib plate;

[0099] (3) Installation of the prefabricated small component 33 of the longitudinal wall plate;

[0100] (4) Installation of the prefabricated small component 34 of the platform plate;

[0101] (5) Installation of the prefabricated small component 35 of the transverse rib plate;

[0102] (6) Installation of the prefabricated intermediate component 36 of the main deck;

[0103] (7) Installation of the prefabricated intermediate component 37 of the longitudinal wall plate and the stiffeners;

[0104] Among them, the tolerance of the upper side section in terms of length is within ±5 mm, the tolerance in terms of width is within ±5 mm, the tolerance in terms of height is within ±5 mm, and the tolerance in terms of flatness is within ≤8 mm.

[0105] In summary, through the preliminary scheme design of the present invention, the reference line is set during the sectional construction process, and the number of additional annular closing joints is determined according to the number of cargo tanks straddling the annular closing joint. The non-residue rate of ship construction is achieved, avoiding the cutting of residues during the sectional assembly and erection. The residues, extension values, and closing welding compensation amounts of the annular closing joints are reasonably added, and the process control during the sectional construction process and the sectional assembly and erection process are carried out to ensure that the tolerances of the bow and stern saddles of a single cargo tank meet the accuracy requirements, realizing the one-time completion of the cargo tank hoisting, reducing rework, improving the construction efficiency, and reducing the construction cost.

[0106] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0107] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A method for controlling the construction accuracy of the cargo tank compartment of a gas carrier, characterized in that, it includes the following steps: Step 1: Set the reference line of the cargo tank compartment; Step 2: Structural cutting design; Obtain the welding shrinkage data of the longitudinal stiffeners, longitudinal girders and floors to the main plate after welding through welding tests, and obtain the heat treatment shrinkage data of the longitudinal stiffeners, longitudinal girders and floors to the main plate after heat treatment through heat treatment tests, and then determine the elongation value added in the length direction of the entire cargo tank compartment; when the length of a single cargo tank across the gas carrier is less than or equal to four ring joints, add operation allowances only at one ring joint of the cargo tank compartment; when the length of a single cargo tank across the gas carrier is greater than four ring joints, add operation allowances at two ring joints of the cargo tank compartment respectively, and the two ring joints are not adjacent in the length direction of the cargo tank compartment along the gas carrier; wherein, the ring joint includes the bottom section joint and the side shell section joint in the same cross-section in the cargo tank compartment; add closing welding compensation at the stern or bow of each section of the cargo tank compartment; Step 3: Segment construction of the cargo tank compartment; construct the bottom section, the lower side shell section and the upper side shell section respectively; Step 4: Sub-assembly; perform bottom section ground sub-assembly and side shell section ground sub-assembly respectively; 4.

1. Bottom section ground sub-assembly, perform ground sub-assembly on each bottom section to form a bottom sub-assembly; 4.

2. Side shell section sub-assembly, the side shell section sub-assembly includes the upper and lower side shell section sub-assembly and the front and rear side shell section sub-assembly; first perform upper and lower sub-assembly on the lower side shell section and the upper side shell section on the jig with the outer plate as the base surface to form side shell sections respectively, and then perform front and rear sub-assembly on each side shell section to form a side shell sub-assembly; wherein, the order of Step 4.1 and Step 4.2 is not in sequence; Step 5: Erection of the cargo tank compartment, adjust the positioning accuracy of the bottom sub-assembly and the side shell sub-assembly.

2. The method for controlling the construction accuracy of the cargo tank compartment of a gas carrier according to claim 1, characterized in that, in the said Step 3, the bottom section is constructed with the outer plate of the bottom section as the base surface; the lower side shell section is constructed with the inclined wall of the lower side shell section as the base surface; the upper side shell section is constructed with the outer plate of the upper side shell section as the base surface.

3. The method for controlling the construction accuracy of the cargo tank compartment of a gas carrier according to claim 1, characterized in that, in the said Step 4.1, when controlling the accuracy in the length direction, by measuring and adjusting the length between the rib position inspection lines and the rib spacing at the joint, control the distance between the two saddles at the bow and stern of the bottom sub-assembly to be a preset value, so that the process tolerance of the length of the two saddles at the bow and stern before welding is within 0mm to +8mm, and the tolerance after welding is within -3mm to +5mm; when controlling the levelness accuracy, by measuring and adjusting the relative height values of the two saddles at the bow and stern of the bottom sub-assembly, and making the four corners of the upper mouth of the saddle web horizontal, and using the measuring points on the T-beam panel close to the saddle as reference points, control the levelness deviation of the bottom sub-assembly ≤8mm; when controlling the center line accuracy, control the deviation of the bow and stern center lines of the bottom sub-assembly from the preset center line ≤3mm, and at the same time control the flatness deviation of the joint on the left and right sides of the bottom sub-assembly ≤5mm.

4. The construction accuracy control method for the cargo tank compartment of a gas carrier ship as claimed in claim 1, characterized in that, in step 4.2, during the overall assembly accuracy control of the upper and lower side shell sections, control the horizontal deviation of the longitudinal wall of the side shell section ≤ 8 mm, and add horizontal measurement points at the saddle positions of the side shell section as reference points; control the relative height value from the main deck of the side shell section to the hull baseline within 0 mm to 5 mm, and add height measurement points at the floating prevention structure positions of the side shell section as reference points; measure the rib position inspection lines of the lower side shell section and the upper side shell section, so that the rib position inspection lines of the lower side shell section and the upper side shell section are in the same plane, control the deviation between the rib position inspection lines of the lower side shell section and the upper side shell section within ±2 mm, and control the front and rear deviation of the saddle web within ±2 mm.

5. The construction accuracy control method for the cargo tank compartment of a gas carrier ship as claimed in claim 1, characterized in that, in step 4.2, during the overall assembly accuracy control of the front and rear side shell sections, measure the flatness of the longitudinal wall of the side shell total section, control the overall horizontal deviation of the longitudinal wall of the side shell total section ≤ 8 mm, and control the straightness deviation of the main deck of the side shell total section ≤ 8 mm; control the overall horizontal deviation of the T-beam panel of the side shell total section ≤ 8 mm, and the alignment flatness deviation of the joints around the side shell total section ≤ 5 mm; measure the length between the rib position inspection lines of the side shell total section and the total length of the side shell total section, so that the process tolerance of the length of the two saddles at the bow and stern before welding of the side shell total section is within 0 mm to +8 mm, and the tolerance after welding is within -3 mm to +5 mm; and control the length deviation between the two saddles at the bow and stern of the side shell total section and the length between the two saddles at the bow and stern of the bottom total section ≤ 5 mm.

6. The construction accuracy control method for the cargo tank compartment of a gas carrier ship as claimed in claim 1, characterized in that, in step 5, during the erection and positioning accuracy control of the bottom total section, in the horizontal accuracy control, measure the levelness of the bottom total section, additionally measure the levelness near the saddle, control the overall levelness deviation of the entire bottom total section ≤ 8 mm, and additionally measure the height value of the saddle web to ensure it is the same as the preset value; in the center line accuracy control, control the deviation between the center line of the bottom total section and the ground sample center line ≤ 3 mm, and measure and control the alignment flatness deviation of the bow and stern openings of the section ≤ 5 mm; in the length accuracy control, control the length deviation of the rib spacing at each joint of the bottom total section within 0 mm to +5 mm, and measure the lengths between each rib position inspection line and the saddle web to ensure they are the same as the preset values.

7. The construction accuracy control method for the cargo tank compartment of a gas carrier ship as claimed in claim 1, characterized in that, in step 5, during the erection and positioning accuracy control of the side shell total section, in the half-width direction accuracy control, measure the half-width of the upper and lower openings of the side shell total section, control the half-width deviation of the upper and lower openings of the inner longitudinal wall of the side shell total section within 0 mm to +5 mm; in the height direction accuracy control, measure the height at the main deck of the side shell total section and the height at the floating prevention block of the side shell total section, control the erection and positioning height deviation of the side shell total section within 0 mm to +5 mm; In the length direction precision control, measure the rib inspection line of the side shell total section and the saddle web of the side shell total section, and control the front-back deviation between the saddle of the side shell total section and the saddle web of the bottom total section within 0 mm to +5 mm. During the installation of the bulk floating prevention structure, measure and control the gap between the floating prevention wooden blocks of the cargo tank and the pads of the floating prevention structure, and control the deviation of the bulk floating prevention structure in the up-down direction within ±5 mm, in the left-right direction within ±5 mm, and in the front-back direction within ±5 mm.

8. The construction precision control method for the cargo tank hold of a gas carrier as claimed in claim 1, characterized in that, in the step 2, the operation allowance added at the circular closing joint is 20 mm.

9. The construction precision control method for the cargo tank hold of a gas carrier as claimed in claim 1, characterized in that, in the step 2, the stretch value is 0.3 mm / rib position.

10. The construction precision control method for the cargo tank hold of a gas carrier as claimed in claim 1, characterized in that, in the step 2, the closing welding compensation amount added at the stern opening or bow opening of each section of the cargo tank hold is 4 mm.

11. The construction precision control method for the cargo tank hold of a gas carrier as claimed in claim 1, characterized in that, in the step 3, control the tolerance of the bottom section in length within ±5 mm, in width within ±5 mm, in height within ±5 mm, and in flatness within ≤8 mm; control the tolerance of the lower side shell section in length within ±5 mm, in width within ±5 mm, in height within ±5 mm, and in flatness within ≤8 mm; control the tolerance of the upper side shell section in length within ±5 mm, in width within ±5 mm, in height within ±5 mm, and in flatness within ≤8 mm.

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