Segmented total assembly positioning method for rudder horn of LNG (Liquefied Natural Gas) ship

Abstract

The invention discloses an LNG (Liquefied Natural Gas) ship rudder horn subsection assembly positioning method, which comprises the following steps of: butting a middle subsection and a rudder horn subsection on a jig frame, then adjusting the rudder horn subsection from front, back, left and right directions, placing a concentricity measuring device right below a lower rudder hole after the rudder horn subsection is adjusted in place, hanging a conical plumb bob at the center of an upper rudder hole by utilizing a steel wire rope, and finally measuring the concentricity of the rudder horn subsection. Adjusting the height of an outer opening of a non-butt-joint part of the rudder horn section, and measuring the distance from the steel wire rope to the inner wall of the lower rudder hole by using a right-angle measuring ruler on the concentricity measuring device in the process, so as to ensure the vertical coplanarity of the circle center of the upper rudder hole and the circle center of the lower rudder hole; the concentricity measuring device can ensure that the conical plumb bob is always in a static state, so that the influence on the measuring precision caused by the movement of the conical plumb bob due to external interference in the measuring process can be avoided, the accuracy of measured data is ensured, and the positioning precision of rudder horn sections and the positioning precision of a rudder system are further ensured.

Description

Technical Field

[0001] The invention relates to the technical field of shipbuilding, and in particular to a method for positioning a sectional assembly of a rudder arm mounted on an LNG ship. Background Art

[0002] The total section where the rudder arm section is located can be divided into three sections: left, middle and right. It is temporarily replaced by P / C / S. P / S is the rudder arm section, and section C is the middle section. P / S is connected to section C respectively. There is a center line mark in the middle of section C. After the horizontal total assembly of section C is placed, the total assembly positioning of the rudder arm section begins. The rudder section is the section at the last end of the entire stern, and it is also the section where the zero rib is located. It has very high positioning accuracy requirements, among which the vertical coplanarity of the upper and lower centers of the rudder hole is particularly important. At present, the method of hanging a plumb bob is usually used to adjust the vertical coplanarity of the upper and lower centers of the rudder hole. However, the current section assembly is an outdoor operation. A slight wind or other interference outdoors will cause the wire rope that fixes the plumb bob to shake, resulting in inaccurate measurement data and a large accuracy error, thereby affecting the subsequent rudder system positioning accuracy. Summary of the invention

[0003] In view of this, the present invention provides a method for positioning a rudder arm segment assembly of an LNG ship, so as to solve the problem that the wire rope of the plumb bob is easily shaken under external interference when positioning the rudder arm segment assembly, thereby affecting the vertical coplanarity of the upper and lower center points of the rudder hole and the positioning accuracy of the rudder arm segment.

[0004] A method for positioning a rudder arm segment assembly on an LNG ship, specifically comprising the following steps:

[0005] S1. According to the construction drawings of the block assembly, determine the positions of the tire frames of the rudder arm block and the middle block, and according to the sizes of the rudder arm block and the middle block and the positions of the rudder holes, mark the zero rib position and the center line of the block on the ground, and mark the intersection between the zero rib position and the center line of the block;

[0006] S2, first hoist the middle section and place it on its tire frame, then place the rudder arm section against the middle section to achieve docking with the middle section;

[0007] S3, adjust the rudder arm sections from the front, rear, left and right directions. After the adjustment is in place, place a concentricity measuring device just below the lower rudder hole, and hang a conical plumb bob at the center of the upper rudder hole using a steel wire rope;

[0008] The conical plumb bob naturally hangs down and extends into the concentricity measuring device, and the concentricity measuring device is used to keep the conical plumb bob in a stationary state during the measurement process to avoid external interference causing the position of the conical plumb bob to move and thus affect the measurement accuracy;

[0009] The concentricity measuring device comprises a cylinder and a measuring ruler arranged on the top or inside of the cylinder, and the diameter of the upper opening of the cylinder is equal to the diameter of the rudder hole;

[0010] S4, using the lifting equipment to adjust the height of the outer opening of the unjoined part of the rudder arm segment, wait until the conical plumb bob is stationary, use the measuring ruler on the cylinder to measure the distance from the steel wire rope to the inner wall of the lower rudder hole, and determine whether the distance from the steel wire rope to the inner wall of the lower rudder hole is equal to the radius of the lower rudder hole. If not, adjust the height of the rudder arm segment again until the distance from the steel wire rope to the inner wall of the lower rudder hole is equal to the radius of the lower rudder hole;

[0011] S5, perform restraint welding on the butt joint between the rudder arm segment and the middle segment. After welding, release the hook of the lifting equipment.

[0012] Preferably, in step S3, the specific steps of adjusting the rudder arm segments from the front, rear, left and right directions are:

[0013] First, adjust the horizontality of the rudder arm segment in the left and right directions according to the horizontality of the segment centerline of the middle segment and the hard stop positions at the four corners. The horizontality of the outer opening of the unjointed part of the rudder arm segment needs to be adjusted 10-20mm higher than that of the joint part.

[0014] Then, adjust the docking width and docking gap between the rudder arm segment and the middle segment according to the segment centerline of the middle segment, and adjust the front and rear direction of the stern cover plate of the rudder arm segment, so that the centerline of the overall segment of the overall assembly is aligned with the centerline of the overall segment drawn on the ground, and the rib position zero on the rudder arm segment is aligned with the rib position zero drawn on the ground.

[0015] Preferably, the butt joint width between the rudder arm segment and the middle segment refers to the distance between the center of the upper rudder hole and the segment centerline of the middle segment, and the butt joint gap between the rudder arm segment and the middle segment refers to the width of the butt joint between the two;

[0016] When adjusting the docking width and docking gap between the rudder arm section and the middle section, priority should be given to ensuring that the difference between the docking width and the theoretical data is within the allowable error range. If the difference between the docking width and the theoretical data between the rudder arm section and the middle section cannot be adjusted to within the allowable error range, adjust the position of the section centerline of the middle section until the requirements are met.

[0017] Preferably, when adjusting the position of the segment centerline of the middle segment, the offset distance of the segment centerline of the middle segment is within 3-5 mm.

[0018] Preferably, the alignment deviation between the center line of the total section of the total assembly and the center line of the total section drawn on the ground should be less than 2 mm, and the alignment deviation between the rib position zero on the rudder arm segment and the rib position zero drawn on the ground should be less than 2 mm.

[0019] Preferably, in step S3, a concentricity measuring device is placed directly below the rudder hole, and a conical plumb bob is hung at the center of the rudder hole. The concentricity measuring device is first placed directly below the rudder hole, and the bottom center of the concentricity measuring device is aligned with the intersection of the zero rib position and the center of the rudder hole;

[0020] Then, hang a conical plumb bob at the center of the rudder hole, and let it hang down naturally and extend into the cylinder of the concentricity measuring device;

[0021] Then, water is added to the cylinder of the concentricity measuring device until the water covers the plumb bob. After the water in the cylinder and the plumb bob are both still, step S4 is executed to adjust the concentricity.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention first docks the middle segment with the rudder arm segment on the tire frame, and then adjusts the rudder arm segment from the front, rear, left and right directions. After the adjustment is in place, a concentricity measuring device is placed directly below the lower rudder hole, and a conical plumb bob is hung at the center of the upper rudder hole using a steel wire rope. Then, the height of the outer opening of the undocking portion of the rudder arm segment is adjusted, and in the process, the distance from the steel wire rope to the inner wall of the lower rudder hole is measured using a right-angle measuring ruler on the concentricity measuring device to ensure the vertical coplanarity between the center of the upper rudder hole and the center of the lower rudder hole. Since the concentricity measuring device can ensure that the conical plumb bob is always in a stationary state, it can avoid external interference during the measurement process that causes the position of the conical plumb to move, thereby affecting the measurement accuracy, thereby ensuring the accuracy of the measurement data, and further ensuring the positioning accuracy of the rudder arm segment and the positioning accuracy of the rudder system.

[0024] 2. When placing the concentricity measuring device just below the lower rudder hole, by aligning the center of the bottom of the cylinder with the intersection of the zero rib position and the segment center line, it can be ensured that the center of the bottom of the cylinder and the center of the lower rudder hole are on the same vertical line. In this way, the distance from the wire rope to the inner wall of the lower rudder hole can be quickly measured by the right-angle measuring ruler on the top of the cylinder. There is no need to climb to the high position where the lower rudder hole is located for measurement. The measurement process is simple, fast and convenient, and it can also ensure the personal safety of construction workers.

[0025] 3. The concentricity measuring device of the present application has a simple structure. It can use a common bucket or cylindrical barrel. It can solve the problem that the wire rope of the plumb bob is prone to shake under external interference when the overall assembly of the rudder arm segment is positioned, thereby affecting the vertical coplanarity of the upper and lower center points of the rudder hole and the positioning accuracy of the rudder arm segment through the simplest structural form, which greatly reduces the construction cost of the enterprise and improves the construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the bob hanging on the rudder arm section.

[0028] Figure 2 It is a front view of a concentricity measuring device placed just below the segmented rudder hole of the rudder arm.

[0029] Figure 3 It is a stereoscopic view of a concentricity measuring device placed just below the segmented rudder hole of the rudder arm.

[0030] Figure 4 It is a fetal position diagram of the rudder arm segments.

[0031] Figure 5 It is a three-dimensional schematic diagram of a concentricity measuring device.

[0032] Figure 6 It is a top view of the concentricity measuring device.

[0033] Figure 7 It is a top view of the rudder arm section and the middle section as a whole.

[0034] The meanings of the numbers in the figure are:

[0035] 1. The rudder arm is divided into sections, 2 is a conical plumb bob, 3 is a cylinder, 4 is a measuring ruler, 5 is a concentricity measuring device, 6 is a wire rope, 7 is a lower rudder hole, 8 is a middle section, 9 is an upper rudder hole, 10 is a butt joint gap, 11 is a section centerline of the middle section or a total section centerline, and 12 is a zero rib position. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0037] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0038] In order to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings.

[0039] The present invention provides a method for positioning a rudder arm segment assembly of an LNG ship, which specifically comprises the following steps:

[0040] S1. According to the construction drawings of the block assembly, determine the positions of the tire frames of the rudder arm block 1 and the middle block 8. According to the length and width of the rudder arm block and the middle block and the position of the rudder hole, mark the zero rib position 12 and the center line of the block 11 on the ground, and mark the intersection of the zero rib position and the center line of the block.

[0041] S2, first hoist the middle segment 8 and place it on its tire frame (the segment center line of the middle segment needs to be aligned with the total segment center line drawn on the ground), and then place the rudder arm segment 1 against the middle segment 8 to achieve docking with the middle segment.

[0042] S3, adjust the rudder arm sections from the front, back, left and right directions:

[0043] Specifically, first, adjust the horizontality of the left and right directions of the rudder arm segment 1 according to the horizontality of the segment centerline of the middle segment 8 and the four corner hard stop positions. The horizontality of the outer opening of the unjointed part of the rudder arm segment 1 needs to be raised by 10-20mm compared with the joint part. Use it after adjustment.

[0044] Then, according to the segment centerline of the middle segment 8, the docking width and the docking gap 10 between the rudder arm segment 1 and the middle segment 8 are adjusted, and the front and rear direction of the stern cover plate of the rudder arm segment 1 is adjusted, so that the centerline of the total segment of the overall assembly is aligned with the centerline of the total segment drawn on the ground, and the rib position No. 0 on the rudder arm segment 1 is aligned with the rib position No. 0 drawn on the ground. The alignment deviation between the centerline of the total segment of the overall assembly and the centerline of the total segment drawn on the ground should be less than 2mm, and the alignment deviation between the rib position No. 0 on the rudder arm segment and the rib position No. 0 drawn on the ground should be less than 2mm.

[0045] The butt joint width between the rudder arm segment 1 and the middle segment mentioned above refers to the distance between the center of the upper rudder hole and the segment centerline of the middle segment, and the butt joint gap between the rudder arm segment 1 and the middle segment refers to the width of the butt joint between the two;

[0046] When adjusting the docking width and docking gap between the rudder arm segment 1 and the middle segment, priority should be given to ensuring that the difference between the docking width and the theoretical data is within the allowable error range, that is, first ensure the docking width, and then ensure that the docking gap meets the requirements when the docking width meets the requirements. The docking gap must be kept within 15mm, and the docking gap at a local position shall not exceed 20mm; if the difference between the docking width and the theoretical data between the rudder arm segment and the middle segment cannot be adjusted to within the allowable error range no matter how it is adjusted, then adjust the position of the segment centerline of the middle segment (that is, the segment centerline of the middle segment can be appropriately offset) until the requirements are met, and the offset distance of the segment centerline of the middle segment is within 3-5mm.

[0047] After the rudder arm segment 1 is adjusted in the front, rear, left and right directions, a concentricity measuring device 5 is placed directly below the rudder hole, and a conical plumb bob 2 is hung at the center of the rudder hole using a steel wire rope 6. The conical plumb bob 2 naturally droops and extends into the concentricity measuring device 5. The concentricity measuring device 5 is used to keep the conical plumb bob 2 in a stationary state during the measurement process to avoid external interference that causes the position of the conical plumb bob 2 to move and thus affect the measurement accuracy. In this embodiment, the concentricity measuring device 5 includes a cylinder 3, a right-angle measuring ruler or a straight ruler 4 arranged on the top of the cylinder 3 or on the inner wall of the cylinder. The right-angle measuring ruler 4 is used to measure the distance from the steel wire rope to the inner wall of the lower rudder hole. The upper opening diameter of the cylinder 3 is equal to the diameter of the lower rudder hole.

[0048] Preferably, the cylinder of the concentricity measuring device 5 can be a common water bucket or a cylindrical barrel, and the measuring ruler 4 can be fixed on the cylinder 3 by welding or by fasteners.

[0049] When setting the concentricity measuring device 5 and the conical plumb bob 2, first place the concentricity measuring device 5 directly below the lower rudder hole, and align the bottom center of the concentricity measuring device 5 with the intersection of the zero rib position and the center of the rudder hole (i.e., the orthographic projection of the center of the rudder hole on the ground); then, hang the conical plumb bob 2 at the center of the rudder hole, and let the conical plumb bob 2 droop naturally and extend into the cylinder of the concentricity measuring device 5; then, add water into the cylinder of the concentricity measuring device 5 until the water covers the plumb bob, and after the water and the plumb bob in the cylinder are both still, execute step S4 to adjust the concentricity.

[0050] S4, using a lifting device to adjust the height of the outer opening of the unjoined portion of the rudder arm segment 1, and after the conical plumb bob 2 is stationary, measure the distance from the steel wire rope to the inner wall of the lower rudder hole to determine whether the distance from the steel wire rope to the inner wall of the lower rudder hole is equal to the radius of the lower rudder hole; if not, adjust the height of the rudder arm segment again until the distance from the steel wire rope to the inner wall of the lower rudder hole is equal to the radius of the lower rudder hole;

[0051] S5, perform restraint welding on the butt joint between the rudder arm segment and the middle segment. After welding, release the hook of the lifting equipment.

[0052] It should be clear that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A method for positioning the rudder arm of an LNG ship in sections, characterized in that: The specific steps include: S1. According to the construction drawings of the block assembly, determine the positions of the tire frames of the rudder arm block and the middle block, and according to the sizes of the rudder arm block and the middle block and the positions of the rudder holes, mark the zero rib position and the center line of the block on the ground, and mark the intersection of the zero rib position and the center line of the block; S2, first hoist the middle section and place it on its tire frame, then place the rudder arm section against the middle section to achieve docking with the middle section; S3, adjust the rudder arm sections from the front, rear, left and right directions. After the adjustment is in place, place the concentricity measuring device just below the rudder hole, and hang a conical plumb bob at the center of the upper rudder hole using a steel wire rope; The conical plumb bob naturally hangs down and extends into the concentricity measuring device, and the concentricity measuring device is used to keep the conical plumb bob in a stationary state during the measurement process to avoid external interference causing the position of the conical plumb bob to move and thus affect the measurement accuracy; The concentricity measuring device comprises a cylinder and a measuring ruler arranged on the top of the cylinder or inside the cylinder, and the diameter of the upper opening of the cylinder is equal to the diameter of the lower rudder hole; S4, using the lifting equipment to adjust the height of the outer opening of the unjoined part of the rudder arm segment, wait until the conical plumb bob is stationary, use the measuring ruler on the cylinder to measure the distance from the steel wire rope to the inner wall of the lower rudder hole, and determine whether the distance from the steel wire rope to the inner wall of the lower rudder hole is equal to the radius of the lower rudder hole. If not, adjust the height of the rudder arm segment again until the distance from the steel wire rope to the inner wall of the lower rudder hole is equal to the radius of the lower rudder hole; S5, perform restraint welding on the butt joint between the rudder arm segment and the middle segment. After welding, release the hook of the lifting equipment.

2. The method for positioning the LNG ship-mounted rudder arm segment assembly according to claim 1 is characterized in that: In step S3, the specific steps of adjusting the rudder arm segments from the front, rear, left and right directions are: First, adjust the horizontality of the rudder arm segment in the left and right directions according to the horizontality of the segment centerline of the middle segment and the hard stop positions at the four corners. The horizontality of the outer opening of the unjointed part of the rudder arm segment needs to be adjusted 10-20mm higher than that of the joint part. Then, adjust the docking width and docking gap between the rudder arm segment and the middle segment according to the segment centerline of the middle segment, and adjust the front and rear direction of the stern cover plate of the rudder arm segment, so that the centerline of the overall segment of the overall assembly is aligned with the centerline of the overall segment drawn on the ground, and the rib position zero on the rudder arm segment is aligned with the rib position zero drawn on the ground.

3. The method for positioning the LNG ship-mounted rudder arm segment assembly according to claim 2 is characterized in that: The butt joint width between the rudder arm segment and the middle segment refers to the distance between the center of the upper rudder hole and the segment centerline of the middle segment, and the butt joint gap between the rudder arm segment and the middle segment refers to the width of the butt joint between the two; When adjusting the docking width and docking gap between the rudder arm section and the middle section, priority should be given to ensuring that the difference between the docking width and the theoretical data is within the allowable error range. If the difference between the docking width and the theoretical data between the rudder arm section and the middle section cannot be adjusted to within the allowable error range, adjust the position of the section centerline of the middle section until the requirements are met.

4. The method for positioning the LNG ship-mounted rudder arm segment assembly according to claim 3 is characterized in that: When adjusting the position of the segment center line of the middle segment, the offset distance of the segment center line of the middle segment is within 3-5 mm.

5. The method for positioning the LNG ship-mounted rudder arm segment assembly according to claim 2 is characterized in that: The alignment deviation between the center line of the total section of the total assembly and the center line of the total section drawn on the ground should be less than 2mm, and the alignment deviation between the zero rib position on the rudder arm segment and the zero rib position drawn on the ground should be less than 2mm.

6. The method for positioning the LNG ship-mounted rudder arm segment assembly according to claim 1 is characterized in that: In step S3, a concentricity measuring device is placed directly below the rudder hole, and a conical plumb bob is hung at the center of the rudder hole. First, place the concentricity measuring device just below the rudder hole, and align the bottom center of the concentricity measuring device with the intersection of the zero rib position and the center of the rudder hole; Then, hang a conical plumb bob at the center of the rudder hole, and let it hang down naturally and extend into the cylinder of the concentricity measuring device; Then, water is added to the cylinder of the concentricity measuring device until the water covers the plumb bob. After the water in the cylinder and the plumb bob are both still, step S4 is executed to adjust the concentricity.

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