Marine inspection method for main bearings of catenary single-point mooring systems

Abstract

This invention relates to the field of bearing testing technology, specifically a method for marine testing of the main bearing of a catenary single-point mooring system. The method includes measuring the axial and radial clearance of the main bearing. A magnetic gauge holder is attached to the upper surface of the inner ring of the main bearing, and a dial indicator is placed against the upper surface of the outer ring. A hydraulic cylinder lifts the rotating part to measure the axial clearance of the main bearing. A magnetic gauge holder is also attached to the upper surface of the outer ring of the main bearing, and a dial indicator is placed against the inner diameter surface of the inner ring. A first chain hoist, a first force gauge, a second chain hoist, and a second force gauge are arranged radially along the same path as the magnetic gauge holder and dial indicator. The radial clearance of the main bearing is then measured. This method enables testing and evaluation of the catenary single-point mooring system while it is in service. Replacement parts and maintenance tools can be prepared based on the test results without downtime, shortening the downtime cycle of the catenary single-point mooring system and significantly reducing losses caused by downtime.

Description

Technical Field

[0001] This invention relates to the field of bearing testing technology, specifically a marine testing method for the main bearing of a catenary single-point mooring device. Background Technology

[0002] With its fewer operational restrictions, high operational efficiency, low cost, and short construction period, the catenary single-point mooring system has significant advantages over traditional island or breakwater terminals. It has become an important terminal type for transshipment of liquid cargo between liquid cargo ships and land tank farms and has a wide range of applications.

[0003] The main bearing is a critical component of a catenary single-point mooring system, connecting the rotating and stationary parts of the floating buoys. It is typically a three-row roller slewing bearing, responsible for achieving relative movement between the rotating and stationary parts and transmitting mooring forces from the liquid cargo vessel to the anchor point on the seabed. Due to the cumulative impact of enormous mooring forces over the years, the main bearing is the most vulnerable and critical component of a catenary single-point mooring system.

[0004] The catenary single-point mooring system has a design life of 25 years. To avoid unplanned downtime due to sudden main bearing failure during its service life, best practice is to schedule a planned downtime every 10 to 15 years, during which the floating buoy is towed back to land for a comprehensive inspection and overhaul of the main bearing. The traditional approach to this involves towing the floating buoy back to land, disassembling it, conducting a thorough inspection of the main bearing, procuring replacement parts for the overhaul, reinstalling the buoy, and then towing it back to sea for reinstallation. During the downtime of the catenary single-point mooring system, the transfer of liquid cargo between liquefied vessels and land-based tank farms is impossible, causing significant losses to related industries. Therefore, shortening the downtime of the catenary single-point mooring system is an inherent need for all stakeholders. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a marine inspection method for the main bearing of a catenary single-point mooring device. This method enables the inspection and evaluation of the catenary single-point mooring device while it is in service. The replacement parts and maintenance tools can be prepared based on the inspection results without stopping the device, thus shortening the downtime cycle of the catenary single-point mooring device and significantly reducing the losses caused by the downtime.

[0006] To achieve the above objectives, the present invention provides a method for marine inspection of the main bearing of a catenary single-point mooring device, comprising a floating buoy, wherein the floating buoy includes a rotating part and a fixed part, and a bearing system is connected to the rotating part and the fixed part respectively, so that the rotating part and the fixed part rotate relative to each other, wherein the bearing system includes a main bearing.

[0007] Marine inspection methods include methods for measuring the axial and radial clearance of main bearings;

[0008] The specific steps of the method for measuring the axial and radial clearance of the main bearing include:

[0009] S410: The magnetic base is attached to the upper end face of the inner ring of the main bearing, and the dial indicator is pressed against the upper end face of the outer ring of the main bearing. The rotating part is lifted by the hydraulic cylinder. The hydraulic cylinder is gradually pressurized to twice the overturning torque of the rotating part. The displacement of the outer ring of the main bearing is measured by the dial indicator. Half of the displacement is the axial clearance of the main bearing. Step S411 begins.

[0010] S411, The magnetic base is attached to the upper end face of the outer ring of the main bearing, and the dial indicator is pressed against the inner diameter surface of the inner ring of the main bearing, and step S412 or step S413 is started.

[0011] S412. The fixed part is connected to the first hand chain hoist, the first hand chain hoist is connected to the first tension gauge, the first tension gauge is connected to the rotating part, the fixed part is connected to the second hand chain hoist, the second hand chain hoist is connected to the second tension gauge, and the second tension gauge is connected to the rotating part; the first hand chain hoist, the first tension gauge, the second tension gauge, and the second hand chain hoist are all arranged on the same radial direction as the magnetic base and dial indicator described in step S411. The first hand chain hoist and the second hand chain hoist are symmetrically arranged, and the first tension gauge and the second tension gauge are symmetrically arranged. Start step S420.

[0012] S413. The fixed part is connected to the first hand chain hoist, the first hand chain hoist is connected to the first force gauge, the first force gauge is connected to the rotating part, the fixed part is connected to the second hand chain hoist, the second hand chain hoist is connected to the second force gauge, the second force gauge is connected to the rotating part, the fixed part is connected to the third hand chain hoist, the third hand chain hoist is connected to the third force gauge, and the third force gauge is connected to the rotating part; the first hand chain hoist and the first force gauge are arranged on the same radial direction as the magnetic base and dial indicator in step S411, the second hand chain hoist and the third hand chain hoist are symmetrically arranged on both sides of the same radial direction as the magnetic base and dial indicator in step S411, the second force gauge and the third force gauge are symmetrically arranged on both sides of the center line, and step S420 begins;

[0013] S420. First, put the second chain hoist in a relaxed state, and slowly increase the pulling force of the first chain hoist to twice the dial indicator reading when there is a significant displacement. Record the dial indicator reading.

[0014] Next, slowly release the first chain hoist to a slack state, then slowly increase the tension of the second chain hoist until it is twice the level when the dial indicator shows a significant displacement reading. Record the dial indicator reading.

[0015] Half of the difference between the two readings is the radial clearance of the main bearing;

[0016] S430. Repeat steps S410-S420 every 90 degrees along the circumference of the main bearing on the floating pontoon, and record the axial clearance and radial clearance of the main bearing. The axial clearance and radial clearance are used to compare with theoretical values ​​to evaluate the technical condition of the main bearing.

[0017] Furthermore, maritime inspection methods include pre-inspection preparation and safety confirmation methods.

[0018] The aforementioned pre-detection preparation and safety verification method includes the following specific steps:

[0019] S110. All electronic products used in the testing process meet explosion-proof requirements;

[0020] S120. Inquire about the basic status of the bearing system of the single-point mooring device operator of the catenary and check the maintenance records of the bearing system in order to have a basic understanding of the main bearing.

[0021] S130. Inquire about the local sea conditions from the operator of the catenary single-point mooring device, and check the input conditions of wind, waves and currents when the device was designed, paying particular attention to the high-frequency direction of wind, waves and currents.

[0022] S140. After the tools and equipment are prepared, conduct the inspection under conditions of calm wind and waves, and without any liquid cargo ships berthing.

[0023] S150. Before testing, replace any flammable or explosive liquid cargo in the pipeline of the catenary single-point mooring device with water or other non-flammable or non-explosive materials. Otherwise, a special safety risk assessment must be conducted and the consent of the catenary single-point mooring device operator must be obtained.

[0024] S160. Before testing, simultaneously shut off the liquid cargo transmission pipeline upstream of the floating buoy and the liquid cargo transmission pipeline downstream of the floating buoy; during testing, when the rotating part is not rotating, keep the rotating part and the fixed part locked, and connect the ground wire between the rotating part and the fixed part.

[0025] Furthermore, marine testing methods include rotational tests and torque measurement methods for the main bearings.

[0026] The specific steps of the rotation test and torque measurement method for the main bearing include:

[0027] S310. Drag the rotating part to rotate counterclockwise and clockwise to check if there is any obvious jamming or abnormal noise during rotation;

[0028] S320. One end of the hand chain hoist is connected to a fixed part, the other end of the hand chain hoist is connected to a force gauge, and the other end of the force gauge is connected to a rotating part. Pulling the hand chain hoist causes the rotating part to rotate, and the starting torque and rotational torque of the rotating part are measured.

[0029] S330. Repeat step S320 every 90 degrees along the circumference of the main bearing on the floating pontoon to measure the starting torque and rotational torque of the rotating part. The starting torque and rotational torque are used to compare with theoretical values ​​to evaluate the technical condition of the bearing.

[0030] Furthermore, the marine inspection method includes a visual inspection method for main bearings, wherein the specific steps of the visual inspection method for main bearings include:

[0031] S210. Open the waterproof cover and visually inspect whether the waterproof cover's protective function is normal, whether water has entered the main bearing housing, whether the lubrication system connection is intact, and whether the lubrication function is normal.

[0032] S220. Visually inspect the main bearing for rust and mechanical damage, and visually inspect the dust seal of the main bearing for damage, and whether the dust seal and the main bearing are tightly fitted.

[0033] S230. After completing the visual inspection of the main bearing, if there are no obvious unacceptable defects, lubricating grease is added to the main bearing, and the rotation test and torque measurement of the main bearing are carried out.

[0034] Furthermore, the marine testing method includes a particle size analysis method for main bearing grease, wherein the specific steps of the particle size analysis method for main bearing grease include:

[0035] S500. Collect the freshly drained grease from the main bearing and send it to the laboratory for particle size distribution analysis. Compare the analysis results with the particle size distribution of new grease of the same brand and model to evaluate the technical condition of the main bearing.

[0036] The beneficial effects of this invention are: it enables the inspection and evaluation of the catenary single-point mooring device while it is in service, and the replacement parts and maintenance tools can be prepared based on the inspection results without stopping the device, thus shortening the downtime cycle of the catenary single-point mooring device and significantly reducing the losses caused by the downtime of the catenary single-point mooring device. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the mooring system of a catenary single-point mooring device in one embodiment of the present invention;

[0038] Figure 2 for Figure 1A partial enlarged view of the bearing system;

[0039] Figure 3 This is a schematic diagram of the arrangement of the hand-operated hoist and the force gauge at the starting position of rotation during the measurement of starting torque and rotational torque in one embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of the arrangement of the hand-operated hoist and the force gauge at the end of the starting position during the measurement of starting torque and rotational torque in one embodiment of the present invention.

[0041] Figure 5 This is a schematic diagram of measuring the axial clearance of the main bearing in one embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram illustrating the measurement of the radial clearance of the main bearing in one embodiment of the present invention;

[0043] Figure 7 This is a schematic diagram of the arrangement of the hand-operated hoist and tension gauge when measuring the radial clearance of the main bearing in one embodiment of the present invention;

[0044] In the picture:

[0045] 100. Anchor point

[0046] 200. Underwater anchor leg

[0047] 300. Floating pontoon; 310. Rotating part; 320. Fixed part.

[0048] 400. Mooring lines,

[0049] 500. Floating hose

[0050] 600. Bearing system; 610. Main bearing; 611. Dustproof seal; 612. Upper end face of inner ring; 613. Upper end face of outer ring; 614. Inner diameter surface of inner ring; 620. Waterproof cover; 621. Main bearing housing; 630. Lubrication system.

[0051] 700. Liquid cargo transfer system

[0052] 10. Hand-operated chain hoist; 11. First hand-operated chain hoist; 12. Second hand-operated chain hoist; 13. Third hand-operated chain hoist.

[0053] 20. Force gauge, 21. First force gauge, 22. Second force gauge, 23. Third force gauge

[0054] 30. Magnetic gauge base; 31. Magnetic gauge base mounting position; 32. Same radial direction; 40. Dial indicator; 50. Hydraulic cylinder.

[0055] 90. Seabed; 91. Submarine pipeline; 92. Water surface. Detailed Implementation

[0056] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0057] See Figure 1 As shown, the mooring system of the catenary single-point mooring device includes an anchor point 100, underwater anchor legs 200, surface buoys 300, mooring lines 400, and floating hoses 500. The surface buoys 300 include a rotating part 310 and a fixed part 320. The rotating part 310 is connected to the liquid cargo vessel via the mooring lines 400 and the floating hoses 500. The fixed part 320 is connected to the seabed 90 via the underwater anchor legs 200 and the anchor point 100, thus securing the catenary single-point mooring device.

[0058] See Figure 2 The bearing system 600 connects the rotating part 310 and the fixed part 320 of the floating buoy 300, and is responsible for the relative movement of the rotating part 310 and the fixed part 320, transmitting the force from the mooring cable 400 and the floating hose 500 to the anchor point 100. The bearing system 600 includes a main bearing 610, a waterproof cover 620 and a lubrication system 630. A main bearing housing 621 is formed inside the waterproof cover 620, and the main bearing 610 is housed within the main bearing housing 621.

[0059] A method for marine inspection of the main bearing of a catenary single-point mooring system, including...

[0060] Preparation and safety verification methods before testing, including specific steps:

[0061] Step S110: All electronic products used in the testing process meet explosion-proof requirements;

[0062] Step S120: Inquire about the basic status of the bearing system 600 from the operator of the catenary single-point mooring device, and check the maintenance records of the bearing system 600 in order to have a basic understanding of the main bearing 610.

[0063] Step S130: Inquire with the operator of the catenary single-point mooring device about the local sea conditions and check the input conditions of wind, waves and currents when the device was designed, paying particular attention to the high-frequency direction of wind, waves and currents.

[0064] Step S140: After the tools and equipment are prepared, conduct the inspection under conditions of calm wind and waves, and without any liquid cargo ships berthing.

[0065] Step S150: Before testing, replace the flammable and explosive liquid cargo in the pipeline of the catenary single-point mooring device with water or other non-flammable and non-explosive materials. Otherwise, a special safety risk assessment must be conducted and the consent of the operator of the catenary single-point mooring device must be obtained.

[0066] Step S160: Before testing, simultaneously shut off the liquid cargo transfer pipeline upstream and downstream of the floating buoy 300. During testing, when the rotating part 310 is not rotating, keep both the rotating part 310 and the fixed part 320 locked, and connect them with a wire to ensure that the two parts have equal potentials. The wire is the ground wire, used to connect the rotating part 310 and the fixed part 320 to ensure that the two parts have equal potentials, thus preventing electric sparks during maintenance and avoiding safety accidents. The ground wire itself is not a component of the buoy but an accessory, and its connection position is not fixed.

[0067] The floating pontoon 300 is connected to the mooring cable 400, as well as the liquid cargo transfer system 700 and the control system. The liquid cargo transfer system 700 consists of pipelines, specifically including a liquid cargo transfer pipeline upstream of the floating pontoon 300 and a liquid cargo transfer pipeline downstream of the floating pontoon 300, which is responsible for transferring liquid cargo from the ship to the subsea pipeline 91. The liquid cargo transfer system 700 has valves upstream and downstream of the floating pontoon 300. In step S160, the valves are closed to block the floating pontoon 300 from the upstream and downstream liquid cargo transfer pipelines, so as to prevent major liquid cargo spill accidents caused by misoperation or damage to the rotating parts.

[0068] It should be noted that the physical condition of the personnel involved in the testing, the wearing of personal protective equipment, the testing behavior, and the testing tools should all meet the safety management regulations of the operator of the catenary single-point mooring device, and metal-to-metal collisions should be avoided during the process to prevent the generation of electrical sparks.

[0069] See also Figure 2 The visual inspection method for main bearings includes the following specific steps:

[0070] Step S210: Open the waterproof cover 620 and visually inspect whether the protective function of the waterproof cover 620 is normal, whether water has entered the main bearing housing 621, whether the lubrication system 630 is properly connected, and whether the lubrication function is normal.

[0071] Step S220: Visually inspect the main bearing 610 for rust and mechanical damage, and visually inspect the dust seal 611 of the main bearing 610 for damage and whether the dust seal 611 and the main bearing 610 are tightly fitted.

[0072] Step S230: After completing the visual inspection of the main bearing 610, if there are no obvious unacceptable defects, apply grease to the main bearing 610 and conduct a rotation test and torque measurement of the main bearing 610.

[0073] The rotation test and torque measurement method for main bearing 610 includes the following specific steps:

[0074] Step S310: Use a tow wheel to tow the floating hose 500 or the rotating part 310 to rotate counterclockwise twice and clockwise twice. Check if there is any obvious jamming during rotation and listen for any abnormal noise.

[0075] Step S320: Connect the rotating part 310 and the fixed part 320 using a hand chain hoist 10 and a force gauge 20. Specifically, one end of the hand chain hoist 10 is connected to the fixed part 320, the other end of the hand chain hoist 10 is connected to the force gauge 20, and the other end of the force gauge 20 is connected to the rotating part 310. Pull the hand chain hoist 10 to rotate the rotating part 310 of the float 300. Figure 3 and Figure 4 As shown, Figure 3 A schematic diagram of the hand chain hoist 10 and the force gauge 20 at the starting position of rotation. Figure 4 The diagram shows the final position of the chain hoist 10 and the force gauge 20. The chain hoist 10 is the driving device. Pulling the chain hoist 10 drives the force gauge 20, which in turn causes the rotating part 310 and the fixed part 320 to rotate relative to each other. The starting torque and the torque during low-speed smooth rotation of the rotating part 310 and the fixed part 320 are measured. Generally, the starting torque is slightly greater than the torque during low-speed smooth rotation. The starting torque is the torque at the instant of starting. The torque during low-speed smooth rotation is the torque during uniform rotation after starting. In specific operation, the starting torque and the torque are determined by the weight of the rotating part 310 and the bearing friction coefficient. The starting torque is the reading of the force gauge 20 when the rotating part 310 and the fixed part 320 just begin to rotate relative to each other. The torque during rotation is the reading of the force gauge 20 when the relative motion between the rotating part 310 and the fixed part 320 enters the low-speed smooth (uniform) rotation stage.

[0076] Step S330: On the floating pontoon 300, repeat step S320 every 90 degrees along the circumference of the main bearing 610 in both clockwise and counterclockwise directions to measure the starting torque and the rotational torque of the rotating part 310 during smooth low-speed rotation. This is used to compare with theoretical values ​​and evaluate the technical condition of the bearing.

[0077] After completing the rotation test and torque measurement of the main bearing 610, and provided there are no obvious unacceptable defects, the axial and radial clearance of the main bearing 610 are measured.

[0078] The method for measuring the axial and radial clearance of the main bearing 610 includes the following specific steps:

[0079] Step S410: Lock the rotating part 310 in the direction of the mooring cable 400 in the downward direction of the high-frequency wind and wave current. Starting from the direction of the rotating part 310 connected to the mooring cable 400, measure the axial and radial clearance of the main bearing 610 every 90 degrees. The downward direction of the high-frequency wind and wave current refers to the direction of the combined action of wind, waves, and current, usually the opposite direction of the incoming wind, waves, and current, but the specific direction is determined by the combination of the wind, waves, and current. Details are as follows:

[0080] Axial clearance measurement steps: as follows Figure 5 As shown, the magnetic base 30 is attached to the upper end face 612 of the inner ring of the main bearing 610, and the dial indicator 40 is pressed against the upper end face 613 of the outer ring of the main bearing 610. The rotating part 310 is lifted by the hydraulic cylinder 50, and the hydraulic cylinder 50 is gradually pressurized to twice the overturning torque of the rotating part 310. The outer ring displacement of the main bearing 610 is measured by the dial indicator 40. Half of the outer ring displacement is the axial clearance of the main bearing 610, and step S411 begins. The overturning torque is calculated from the weight of the rotating part 310 and the bearing diameter.

[0081] Radial clearance measurement steps: as follows Figure 6 As shown, in step S411, the magnetic base 30 is attracted to the upper end face 613 of the outer ring of the main bearing 610, and the dial indicator 40 presses against the inner diameter surface 614 of the inner ring of the main bearing 610, thus starting step S412 or step S413; in step S412, the fixed part 320 is connected to the first hand chain hoist 11, the first hand chain hoist 11 is connected to the first force gauge 21, the first force gauge 21 is connected to the rotating part 310, and the fixed part 320 is connected to the second hand chain hoist 12. If the opposite sides of the first hand chain hoist 11 and the first force gauge 21 are... If there is no structure, the fixed part 320 is connected to the second hand chain hoist 12, the second hand chain hoist 12 is connected to the second force gauge 22, and the second force gauge 22 is connected to the rotating part 310; the first hand chain hoist 11, the first force gauge 21, the second hand chain hoist 12 and the second force gauge 22 are all set on the same radial direction 32 as the magnetic base 30 and the dial indicator 40 in step S411. The first hand chain hoist 11 and the second hand chain hoist 12 are symmetrically arranged, and the first force gauge 21 and the second force gauge 22 are symmetrically arranged. Step S420 begins.

[0082] See Figure 7 In this embodiment, the first chain hoist 11 and the first force gauge 21 have structures on opposite sides and cannot be placed symmetrically. In order to ensure that they are opposite to the first chain hoist 11 and the first force gauge 21, this embodiment starts step S413.

[0083] Step S413: The fixed part 320 is connected to the first hand chain hoist 11, the first hand chain hoist 11 is connected to the first force gauge 21, the first force gauge 21 is connected to the rotating part 310, the fixed part 320 is connected to the second hand chain hoist 12, the second hand chain hoist 12 is connected to the second force gauge 22, the second force gauge 22 is connected to the rotating part 310, the fixed part 320 is connected to the third hand chain hoist 13, the third hand chain hoist 13 is connected to the third force gauge 23, and so on. The three force gauges 23 are connected to the rotating part 310; the first hand chain hoist 11 and the first force gauge 21 are set on the same radial direction 32 as the magnetic base 30 and the dial indicator 40 in step S411; the second hand chain hoist 12 and the third hand chain hoist 13 are symmetrically set on both sides of the center line with the same radial direction 32 as the center line of the magnetic base 30 and the dial indicator 40 in step S411; the second force gauge 22 and the third force gauge 23 are symmetrically set on both sides of the center line; and step S420 begins.

[0084] It should be noted that in this embodiment, a second chain hoist 12, a second force gauge 22, and a third chain hoist 13 and a third force gauge 23 are respectively arranged on both sides of the structure opposite to the first chain hoist 11 and the first force gauge 21. When tightening the second chain hoist 12 and the third chain hoist 13, the second chain hoist 12 and the third chain hoist 13 need to be tightened simultaneously, and the readings of the second chain hoist 12 and the third chain hoist 13 should be kept as similar as possible. The second chain hoist 12 and the second force gauge 22 should ideally be arranged symmetrically with the first chain hoist 11 and the first force gauge 21 on the same radial direction 32, so that only one set of chain hoists and force gauges arranged on the opposite side of the first chain hoist 11 and the first force gauge 21 is needed. In this embodiment, since there is a structure on the opposite side, it is inconvenient to arrange them. Therefore, two sets of chain hoists and force gauges are arranged on the opposite side. In actual operation, the arrangement method in step S412 or step S413 can be selected according to the specific situation.

[0085] Step S420: First, put the two sets of second chain hoists 12 and 13 into a relaxed state. Slowly increase the pulling force of the first chain hoist 11 to twice the value when the dial indicator 40 shows a significant displacement reading, with a maximum of no more than 3.2 tons. In this embodiment, 3.2 tons is a preset value in the design stage of this type of single-point mooring device. The maximum threshold in this step is determined according to the preset value in the design stage of the single-point mooring device to be measured. Record the reading of the dial indicator 40. Second, slowly release the first chain hoist 11 to a relaxed state. Slowly increase the pulling force of the two sets of second chain hoists 12 and 13 to twice the value when the dial indicator 40 shows a significant displacement reading, with a maximum of no more than 3.2 tons. Record the reading of the dial indicator 40. Half of the difference between the two readings is the radial clearance of the main bearing 610.

[0086] Step S430: Repeat steps S410-S420 every 90 degrees along the circumference of the main bearing 610 on the floating pontoon 300, and record the axial clearance and radial clearance of the main bearing 610.

[0087] The axial and radial clearances of the main bearing are recorded for comparison with theoretical values ​​to assess the technical condition of the main bearing 610.

[0088] The particle size analysis method for main bearing grease includes the following steps:

[0089] Step S500: Collect the newly discharged grease from the main bearing 610 and send it to the laboratory for particle size distribution analysis. The analysis results are compared with the particle size distribution of new grease of the same brand and model to evaluate the technical condition of the main bearing 610.

[0090] The technical condition of the main bearing 610 is comprehensively evaluated based on the results of the above four dimensions of testing, the overhaul plan for the main bearing 610 is determined, and replacement parts are procured in advance.

[0091] The above-mentioned method for inspecting the main bearing of the catenary single-point mooring device at sea differs from traditional practices. While the catenary single-point mooring device is in service at sea, the main bearing 610 is inspected using the device's own conditions, through visual, auditory, measurement, and sampling instrumental analysis. This method is used to assess the technical condition of the main bearing 610, formulate a major overhaul plan for the main bearing 610, and procure the necessary replacement parts during the service life of the catenary single-point mooring device.

[0092] Compared with traditional methods, the inspection of the main bearing 610 and the procurement of replacement parts are carried out while the catenary single-point mooring device is in service. After the replacement parts and maintenance tools are ready, the catenary single-point mooring device is shut down and the buoy is towed back to land for maintenance. This greatly shortens the downtime of the catenary single-point mooring device and significantly reduces the losses caused by the downtime of the catenary single-point mooring device.

[0093] The above-mentioned marine inspection method for the main bearing of the catenary single-point mooring device utilizes the inherent conditions of the catenary single-point mooring device. It conducts inspections in four dimensions: visual inspection of the main bearing 610, rotation test and torque measurement of the main bearing 610, axial and radial clearance measurement of the main bearing 610, and particle size distribution measurement of the main bearing 610 grease. These methods are used to assess the technical condition of the main bearing 610 and determine the maintenance plan for the main bearing 610.

[0094] The aforementioned catenary single-point mooring device allows the inspection and evaluation of the main bearing 610 to be carried out during the service life of the equipment. It allows the inspection and overhaul to be separated and organized separately, providing a basis for more accurate overhaul planning and a reference and basis for maintenance and upkeep during the service life of the equipment.

[0095] In addition, the inspection of the main bearing 610 and the procurement of replacement parts can be carried out during the service of the equipment, which greatly shortens the downtime of the catenary single-point mooring device due to major overhaul and significantly reduces the losses caused by the downtime of the catenary single-point mooring device.

[0096] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0097] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0098] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0099] In this invention, unless otherwise explicitly specified and limited, "above" or "below" a second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of a second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" a second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. It should be noted that when an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "above," "below," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

Claims

1. A method for marine inspection of the main bearing of a single-point mooring device for a catenary, comprising a floating buoy, the floating buoy including a rotating part and a fixed part, a bearing system connected to the rotating part and the fixed part respectively, so that the rotating part and the fixed part rotate relative to each other, the bearing system including a main bearing, characterized in that: Marine inspection methods include methods for measuring the axial and radial clearance of main bearings; The specific steps of the method for measuring the axial and radial clearance of the main bearing include: S410: The magnetic base is attached to the upper end face of the inner ring of the main bearing, and the dial indicator is pressed against the upper end face of the outer ring of the main bearing. The rotating part is lifted by the hydraulic cylinder. The hydraulic cylinder is gradually pressurized to twice the overturning torque of the rotating part. The displacement of the outer ring of the main bearing is measured by the dial indicator. Half of the displacement is the axial clearance of the main bearing. Step S411 begins. S411, The magnetic base is attached to the upper end face of the outer ring of the main bearing, and the dial indicator is pressed against the inner diameter surface of the inner ring of the main bearing, and step S412 or step S413 is started. S412. The fixed part is connected to the first hand chain hoist, the first hand chain hoist is connected to the first tension gauge, the first tension gauge is connected to the rotating part, the fixed part is connected to the second hand chain hoist, the second hand chain hoist is connected to the second tension gauge, and the second tension gauge is connected to the rotating part; the first hand chain hoist, the first tension gauge, the second tension gauge, and the second hand chain hoist are all arranged on the same radial direction as the magnetic base and dial indicator described in step S411. The first hand chain hoist and the second hand chain hoist are symmetrically arranged, and the first tension gauge and the second tension gauge are symmetrically arranged. Start step S420. S413. The fixed part is connected to the first hand chain hoist, the first hand chain hoist is connected to the first force gauge, the first force gauge is connected to the rotating part, the fixed part is connected to the second hand chain hoist, the second hand chain hoist is connected to the second force gauge, the second force gauge is connected to the rotating part, the fixed part is connected to the third hand chain hoist, the third hand chain hoist is connected to the third force gauge, and the third force gauge is connected to the rotating part; the first hand chain hoist and the first force gauge are arranged on the same radial direction as the magnetic base and dial indicator in step S411, the second hand chain hoist and the third hand chain hoist are symmetrically arranged on both sides of the same radial direction as the magnetic base and dial indicator in step S411, the second force gauge and the third force gauge are symmetrically arranged on both sides of the center line, and step S420 begins; S420. First, put the second chain hoist in a relaxed state, and slowly increase the pulling force of the first chain hoist to twice the dial indicator reading when there is a significant displacement. Record the dial indicator reading. Next, slowly release the first chain hoist to a slack state, then slowly increase the tension of the second chain hoist until it is twice the level when the dial indicator shows a significant displacement reading. Record the dial indicator reading. Half of the difference between the two readings is the radial clearance of the main bearing; S430. Repeat steps S410-S420 every 90 degrees along the circumference of the main bearing on the floating pontoon, and record the axial clearance and radial clearance of the main bearing. The axial clearance and radial clearance are used to compare with theoretical values ​​to evaluate the technical condition of the main bearing.

2. The method for marine inspection of the main bearing of a catenary single-point mooring device according to claim 1, characterized in that: Marine inspection methods include pre-inspection preparation and safety confirmation methods. The aforementioned pre-detection preparation and safety verification method includes the following specific steps: S110. All electronic products used in the testing process meet explosion-proof requirements; S120. Inquire about the basic status of the bearing system of the single-point mooring device operator of the catenary and check the maintenance records of the bearing system in order to have a basic understanding of the main bearing. S130. Inquire about the local sea conditions from the operator of the catenary single-point mooring device, and check the input conditions of wind, waves and currents when the device was designed, paying particular attention to the high-frequency direction of wind, waves and currents. S140. After the tools and equipment are prepared, conduct the inspection under conditions of calm wind and waves, and without any liquid cargo ships berthing. S150. Before testing, replace any flammable or explosive liquid cargo in the pipeline of the catenary single-point mooring device with water or other non-flammable or non-explosive materials. Otherwise, a special safety risk assessment must be conducted and the consent of the catenary single-point mooring device operator must be obtained. S160. Before testing, simultaneously shut off the liquid cargo transmission pipeline upstream of the floating buoy and the liquid cargo transmission pipeline downstream of the floating buoy; during testing, when the rotating part is not rotating, keep the rotating part and the fixed part locked, and connect the ground wire between the rotating part and the fixed part.

3. The method for marine inspection of the main bearing of a catenary single-point mooring device according to claim 1, characterized in that: Marine testing methods include rotational testing and torque measurement of main bearings. The specific steps of the rotation test and torque measurement method for the main bearing include: S310. Drag the rotating part to rotate counterclockwise and clockwise to check if there is any obvious jamming or abnormal noise during rotation; S320. One end of the hand chain hoist is connected to a fixed part, the other end of the hand chain hoist is connected to a force gauge, and the other end of the force gauge is connected to a rotating part. Pulling the hand chain hoist causes the rotating part to rotate, and the starting torque and rotational torque of the rotating part are measured. S330. Repeat step S320 every 90 degrees along the circumference of the main bearing on the floating pontoon to measure the starting torque and rotational torque of the rotating part. The starting torque and rotational torque are used to compare with theoretical values ​​to evaluate the technical condition of the bearing.

4. The method for marine inspection of the main bearing of a catenary single-point mooring device according to claim 1, characterized in that: The marine inspection method includes a visual inspection method for main bearings, the specific steps of which include: S210. Open the waterproof cover and visually inspect whether the waterproof cover's protective function is normal, whether water has entered the main bearing housing, whether the lubrication system connection is intact, and whether the lubrication function is normal. S220. Visually inspect the main bearing for rust and mechanical damage, and visually inspect the dust seal of the main bearing for damage, and whether the dust seal and the main bearing are tightly fitted. S230. After completing the visual inspection of the main bearing, if there are no obvious unacceptable defects, lubricating grease is added to the main bearing, and the rotation test and torque measurement of the main bearing are carried out.

5. The method for marine inspection of the main bearing of a catenary single-point mooring device according to claim 4, characterized in that: The marine testing method includes a particle size analysis method for main bearing grease, wherein the specific steps of the particle size analysis method for main bearing grease include: S500. Collect the freshly drained grease from the main bearing and send it to the laboratory for particle size distribution analysis. Compare the analysis results with the particle size distribution of new grease of the same brand and model to evaluate the technical condition of the main bearing.

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