Marine hose management system and method

Abstract

Provided is a marine hose management system and method that makes it possible to easily and accurately determine the level of fatigue of a reinforcement cord forming a marine hose, while achieving power saving. A detection unit 10 including an acceleration sensor 11, a storage unit 12, a control unit 13, and a battery 15 is installed on a marine hose 1. Each detection operation by the sensor 11 is set to a predetermined short period of time. The sampling frequency of detection data by the sensor 11 is set to 100 Hz - 200 Hz. A normal period in which the magnitude of acceleration in the detection data is less than or equal to a first threshold, a medium-scale rough period in which the magnitude is greater than the first threshold but less than or equal to a second threshold, and a large-scale rough period in which the magnitude is greater than the second threshold are defined, and the frequency of execution of the detection operation in each period is increased in this order of the periods. The detection operation is controlled to be executed at intervals of less than or equal to 120 minutes in the normal period. The level of fatigue of the reinforcement cord is determined by a computing device 16 on the basis of respective detection data stored in the storage unit 12.

Description

Marine hose management system and method

[0001] The present invention relates to a marine hose management system and method, and more particularly to a marine hose management system and method that can easily and accurately determine the degree of fatigue of a reinforcing cord that constitutes a marine hose while saving energy.

[0002] Marine hoses are repeatedly subjected to forces, primarily from waves, during use, causing them to bend in various directions. This gradually fatigues the reinforcing cords that make up the hose, and the hose must be replaced before the reinforcing cords exceed their fatigue limit. Because the degree of reinforcing cord fatigue cannot be determined from the hose's appearance, marine hoses are often replaced simply based on the length of time they have been used. However, because the degree of reinforcing cord fatigue varies greatly depending on the conditions under which the hose is used (such as the strength of the waves in the area where it is used), simply replacing the hose based on the length of time it has been used does not allow the hose to be used effectively without exceeding or deviating from the reinforcing cord's fatigue limit. As a result, marine hoses that still have plenty of use are often wasted.

[0003] It has been proposed to install an acceleration sensor in a marine hose to determine the forces acting on the marine hose (see Patent Document 1). However, simply detecting acceleration using an acceleration sensor installed in a marine hose is not enough to accurately determine the degree of fatigue of the reinforcing cords that make up the marine hose. Furthermore, a battery is used to operate the acceleration sensor. Since detecting acceleration frequently increases the power consumption of the acceleration sensor in order to accurately determine the degree of fatigue of the reinforcing cords, a larger battery is required to detect acceleration over a long period of time. Increasing the size of the battery installed in the marine hose increases the risk of the battery coming into contact with floating objects, etc., or falling off the marine hose. Therefore, there is room for improvement in a simple, energy-efficient method for accurately determining the degree of fatigue of the reinforcing cords that make up the marine hose.

[0004] Japanese Patent Application Publication No. 11-182748

[0005] An object of the present invention is to provide a marine hose management system and method that can easily and accurately determine the degree of fatigue of a reinforcing cord that constitutes a marine hose while saving power.

[0006] In order to achieve the above object, the marine hose management system of the present invention is a marine hose management system comprising a detection unit installed on the marine hose and a computing device installed outside the marine hose, wherein the detection unit has an acceleration sensor, a memory unit for storing detection data by the acceleration sensor, a control unit for controlling the acceleration sensor, and a battery for providing power to components of the detection unit, wherein the detection operation by the acceleration sensor is set to a predetermined short time each time, and the sampling frequency of the detection data by the acceleration sensor is set to 100 Hz or more and 200 Hz or less. The detection data is divided into a normal period in which the magnitude of acceleration is equal to or less than a first threshold, a medium-scale roughness period in which the magnitude of acceleration exceeds the first threshold and is equal to or less than a second threshold, and a large-scale roughness period in which the magnitude of acceleration exceeds the second threshold, and the detection operation is performed more frequently in each period in the order of the normal period, the medium-scale roughness period, and the large-scale roughness period, and the control unit controls the detection operation to be performed at intervals of 120 minutes or less in the normal period, and the arithmetic unit is configured to determine the degree of fatigue of the reinforcing cords that constitute the marine hose based on the detection data stored in the memory unit.

[0007] A marine hose management method of the present invention uses a detection unit installed on the marine hose and a computing device installed outside the marine hose, the detection unit comprising an acceleration sensor, a memory unit in which detection data from the acceleration sensor is stored, a control unit for controlling the acceleration sensor, and a battery that serves as a power source for components of the detection unit, the method setting the duration of each detection operation by the acceleration sensor to a predetermined short time and setting the sampling frequency of the detection data from the acceleration sensor to be between 100 Hz and 200 Hz, dividing the magnitude of acceleration in the detection data into a normal period where the magnitude of acceleration is equal to or less than a first threshold, a medium-scale roughness period where the magnitude of acceleration is above the first threshold and equal to or less than a second threshold, and a large-scale roughness period where the magnitude of acceleration is above the second threshold, and increasing the frequency of the detection operation in each period in the order of the normal period, the medium-scale roughness period, and the large-scale roughness period, and controlling the control unit to execute the detection operation at intervals of 120 minutes or less during the normal period, and the computing device determining the degree of fatigue of the reinforcing cords that make up the marine hose based on the respective detection data stored in the memory unit.

[0008] According to the present invention, the acceleration sensor is configured to perform each detection operation for a predetermined short time, and the sampling frequency of the detection data is configured to be 100 Hz or more and 200 Hz or less. The detection operation is performed more frequently during the normal period, the medium-scale weather storm period, and the large-scale weather storm period, in that order. During the normal period, the detection operation is performed at intervals of 120 minutes or less. This allows for sufficient acquisition of detection data useful for estimating the fatigue level of the reinforcement cord while minimizing power consumption. The computation device determines the fatigue level of the reinforcement cord based on the acquired detection data, thereby saving power and improving the accuracy of the fatigue level estimation. This is advantageous for effectively using the marine hose without exceeding or deviating from the fatigue limit of the reinforcement cord. Furthermore, the battery can be prevented from becoming larger, which is advantageous for preventing damage to the battery (the detection unit) or its detachment from the marine hose. The fatigue level can be easily determined using the detection unit and the computation device.

[0009] FIG. 1 is an explanatory diagram illustrating an embodiment of a management system. FIG. 2 is an explanatory diagram illustrating an enlarged longitudinal cross-section of a portion of the marine hose of FIG. 1. FIG. 3 is an explanatory diagram illustrating an example of a portion of the marine hose taken along the A-A cross-section of FIG. 2. FIG. 4 is an explanatory diagram illustrating the interior of the detection unit of FIG. 2. FIG. 5 is an explanatory diagram illustrating the behavior of the marine hose in a plan view (X-Y plane). FIG. 6 is an explanatory diagram illustrating the behavior of the marine hose in a front view (X-Z plane). FIG. 7 is a graph illustrating the detection data obtained by the acceleration sensor and the frequency of the detection operation over time. FIG. 8 is a graph illustrating the relationship between the curvature of the hose in a repeated bending test and the number of bends until the reinforcement cord reaches its fatigue limit. FIG. 9 is a graph illustrating the relationship between the exercise intensity and exercise time of the marine hose. FIG. 10 is an explanatory diagram illustrating the relationship between the cumulative exercise time, replacement timing, and fatigue limit of the reinforcement cord of the marine hose. FIG. 11 is an explanatory diagram illustrating an enlarged longitudinal cross-section of a portion of a marine hose to which another embodiment of the management system is applied.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A marine hose management system (hereinafter referred to as a management system) and a management method according to the present invention will be described below based on an embodiment shown in the drawings.

[0011] The embodiment of the management system illustrated in FIG. 1 manages various types of marine hoses 1. The marine hose 1 illustrated in FIG. 1 is a floating type used while floating on the water's surface, but this management system can also be applied to submarine types used submerged. The marine hose 1 is composed of a cylindrical hose body and connecting fittings 2 connected to both longitudinal ends of the hose body. Each connecting fitting 2 has a nipple 2b extending longitudinally of the hose body and a flange 2a joined to one longitudinal end of the nipple 2b. The marine hoses 1 are connected to each other via the connecting fittings 2, and typically, approximately 10 marine hoses 1 are connected to form a hose line.

[0012] 2 and 3, the hose body of the marine hose 1 is laminated in the following order from the inner periphery to the outer periphery: an inner surface layer 3, a first reinforcing layer 4, a main body wire layer 5, a fluid retention layer 7, a second reinforcing layer 6, a buoyancy layer 8, and an outer surface layer 9. The main body wire layer 5 can be provided as desired. Note that arrows X, Y, and Z in the figures indicate the longitudinal direction, depth direction (thickness direction), and height direction of the marine hose 1, respectively, and are oriented perpendicular to one another.

[0013] This marine hose 1 is of double carcass specification, having a fluid retention layer 7 between a first reinforcing layer 4 and a second reinforcing layer 6 laminated at a distance in the radial direction of the hose body. The inner peripheral region of the inner surface layer 3 forms a flow path 1a for the fluid L. Examples of the fluid L include crude oil, heavy oil, gasoline, LPG, water, seawater, and chemicals (alcohols refined from gasoline).

[0014] The inner surface layer 3 is made of a material that is selected appropriately depending on the type of fluid L and has excellent durability and erosion resistance against the fluid L. When the fluid L is crude oil, heavy oil, gasoline, or the like, the inner surface layer 3 is made of nitrile rubber or the like that has excellent oil resistance.

[0015] The first reinforcing layer 4 and the second reinforcing layer 6 are each constructed by laminating multiple reinforcing cord layers, each of which is made of a large number of parallel-arranged reinforcing cords coated with rubber. Repeated bending of the marine hose 1 causes fatigue in the reinforcing cords, so in this embodiment, the degree of fatigue of these reinforcing cords is monitored. The main body wire layer 5 is constructed by spirally winding metal wires at predetermined intervals around the outer circumferential surface of the first reinforcing layer 4. The first reinforcing layer 4, main body wire layer 5, and second reinforcing layer 6 are fixed to their respective nipples 2b using nipple wires 4w, 5w, and 6w at both ends of each layer and fixing rings 2c protruding from the outer circumferential surfaces of the nipples 2b at both ends of the hose body.

[0016] The fluid retention layer 7 formed between the first reinforcing layer 4 and the second reinforcing layer 6 serves as a space for storing fluid L leaked from the flow path 1a. The buoyancy layer 8 is made of a material, such as sponge rubber or foamed polyurethane, that exerts buoyancy to float the marine hose 1 on the sea surface. The outer surface layer 9 is made of a water-impermeable material, such as rubber. This marine hose 1 is a double-carcass type equipped with the fluid retention layer 7, but it may also be a single-carcass type that does not have the fluid retention layer 7.

[0017] This management system comprises a detection unit 10 installed in the marine hose 1 and a computing device 16 installed outside the marine hose 1. In this embodiment, the computing device 16 is installed in a location remote from the place where the marine hose 1 is used, but it may also be installed on a ship or the like in the sea area where the marine hose 1 is used. A well-known computer is used as the computing device 16, and various calculation processes are performed by the computing device 16 using input data. Detection data D from the acceleration sensor 11 that constitutes the detection unit 10 is also input to the computing device 16, and the degree of fatigue of the reinforcing cord that constitutes the marine hose 1 is calculated based on this detection data D.

[0018] In this embodiment, the detection unit 10 is mounted on the outer peripheral surface of the nipple 2b and is exposed on the surface of the marine hose 1. The entire detection unit 10 is housed in a waterproof case, but is generally installed so that it is positioned above water. The detection unit 10 can be installed in other positions, but it is preferably installed so that it does not protrude outward beyond the flange 2a to avoid problems such as damage due to collision with floating objects, etc.

[0019] A detection unit 10 can be installed on each marine hose 1 that makes up the hose line, but adjacent marine hoses 1 generally exhibit similar behavior. However, the behavior of the marine hose 1 differs between both longitudinal ends of the hose line and a position midway along the length. Therefore, it is recommended to install a detection unit 10 on each marine hose 1, 1 located at both longitudinal ends of the hose line, and on at least one marine hose 1 located midway along the length. Because the behavior of a marine hose 1 located in the longitudinal center of the hose line is likely to be large, it is recommended to install a detection unit 10 on one marine hose 1 located in that position.

[0020] As shown in Fig. 4, the detection unit 10 has an acceleration sensor 11, a memory section 12 in which detection data D from the acceleration sensor 11 is stored, a control section 13 that controls the acceleration sensor 11, and a battery 15. The battery 15 serves as a power source for the components of the detection unit 10. Various known memories are used for the memory section 12, and various known processors (CPUs) are used for the control section 13. In this embodiment, a memory that is detachable from the detection unit 10 is used as the memory section 12. Various known types of battery 15 can be used, and for example, a lightweight and compact lithium battery is used. The detection unit 10 with the built-in battery 15 may have a volume of, for example, 100 cm 3 Below (60cm 3 ~80cm 3 approximately 100g in weight (approximately 60g to 80g).

[0021] Various known types of acceleration sensor can be used as the acceleration sensor 11, such as a triaxial acceleration sensor, a two-axis acceleration sensor, etc. The triaxial acceleration sensor detects acceleration in the X, Y, and Z directions, while the two-axis acceleration sensor detects acceleration in the Y and Z directions.

[0022] As shown in Figures 5(A), (B), and (C), the marine hose 1 in use repeatedly bends in the Y direction in a plan view. Furthermore, as shown in Figures 6(A), (B), and (C), the marine hose 1 in use repeatedly bends in the Z direction in a front view. Along with these bends, the marine hose 1 also swings in the X direction. Such behavior of the marine hose 1 causes fatigue in the reinforcing cords that make up the marine hose 1.

[0023] The acceleration sensor 11 detects the acceleration acting on the marine hose 1 in accordance with this behavior. The magnitude of this acceleration is proportional to the force acting on the marine hose 1, and the direction, period, duration, etc. of this acceleration correspond to the state of the force acting on the marine hose 1. Therefore, the detection data D from the acceleration sensor 11 can be used to understand the degree of fatigue of the reinforcing cords that make up the marine hose 1. Therefore, in this embodiment, the detection data D (acceleration) is used to quantify the degree of wild movement of the marine hose 1. Note that fatigue of the reinforcing cords is mainly caused by bending of the marine hose 1, and is little affected by fluctuations in the longitudinal direction (X direction) of the marine hose 1. Therefore, the acceleration sensor 11 is not limited to a triaxial acceleration sensor, and a two-axis acceleration sensor can also be used.

[0024] Each detection operation by the acceleration sensor 11 is set in advance for a predetermined short period of time, for example, between one and two minutes. If each detection operation is performed for one minute or more, it is possible to accurately grasp the behavior of the marine hose 1 at that time (the magnitude and state of the force acting on the marine hose 1). Therefore, it is not necessary to perform the detection operation by the acceleration sensor 11 continuously. By performing the detection operation for a short period of time, between one and two minutes, at a predetermined execution frequency, it is possible to obtain useful detection data D while suppressing power consumption of the battery 15. The predetermined execution frequency for the detection operation is, for example, between 5 and 120 minutes, and will be described in detail below.

[0025] The sampling frequency of the detection data D by the acceleration sensor 11 is set to 100 Hz or more and 200 Hz or less. The sampling frequency is the number of times per second that the acceleration sensor 11 detects acceleration when performing a detection operation. The higher the sampling frequency, the more detailed the behavior of the marine hose 1 (the magnitude and state of the force acting on the marine hose 1) can be grasped, but the power consumption of the battery 15 increases. As a result of various studies, it was found that a sampling frequency of approximately 100 Hz or more can grasp the magnitude and state of the force acting on the marine hose 1 in a generally accurate manner. Therefore, by setting the sampling frequency to 100 Hz or more and 200 Hz or less, it is possible to accurately grasp the magnitude and state of the actual force acting on the marine hose 1 while suppressing the power consumption of the battery 15.

[0026] Figure 7 shows a schematic example of acceleration data (detected data D) detected by the acceleration sensor 11 installed on the marine hose 1. The acceleration on the vertical axis of Figure 7 indicates the roughness of the sea area in which the marine hose 1 is used, i.e., the degree of movement of the marine hose 1 (the behavior of the marine hose 1). In Figure 7, the acceleration detected by the acceleration sensor 11 gradually increases over time, reaches a peak, and then gradually decreases. Figure 7 shows an example of detected data D when a typhoon gradually approaches, arrives, and then recedes into a calm sea area in which the marine hose 1 is used.

[0027] 7, the detection data D is divided into a normal period T1 where the magnitude of acceleration is equal to or less than a first threshold, a medium-scale rough period T2 where the magnitude of acceleration exceeds the first threshold and is equal to or less than a second threshold, and a severe rough period T3 where the magnitude of acceleration exceeds the second threshold. The normal period T1, medium-scale rough period T2, and severe rough period T3 correspond to normal conditions in the sea area where the marine hose 1 is used (a state in which there are no abnormal weather conditions such as typhoons in the surrounding area), rough conditions before and after the arrival of a typhoon, and severe rough conditions after the arrival of a typhoon, respectively. The magnitude of the force acting on the marine hose 1, which greatly affects the fatigue state of the reinforcing cord, and the associated force state, differ between the periods T1, T2, and T3, and therefore the periods T1, T2, and T3 are divided into these periods using the first and second thresholds.

[0028] Regarding the ratios of the normal period T1, the medium-rough period T2, and the severe-rough period T3 in a year, the normal period T1 is generally the longest, but the ratios of each period T1, T2, and T3 vary depending on the sea area. Since the roughness of the sea area differs depending on the sea area where the marine hose 1 is used, the first and second thresholds are appropriately set for each sea area based on past wave observation data for that sea area. The magnitude of the acceleration of the second threshold is often about three times the magnitude of the acceleration of the first threshold, so it is set, for example, in the range of two to four times the magnitude of the acceleration of the first threshold.

[0029] The rougher the sea area, the greater the force acting on the marine hose 1 and the greater the fluctuation of that force, causing the reinforcement cords constituting the marine hose 1 to fatigue more quickly. Furthermore, the more frequently the acceleration sensor 11 performs its detection operation, the greater the power consumption of the battery 15. Therefore, in this embodiment, in order to suppress the power consumption of the battery 15 and to more accurately grasp the degree of fatigue of the reinforcement cords, the control unit 13 controls the acceleration sensor 11 to perform its detection operation (detection frequency of detection data D) more frequently in each of the periods T1, T2, and T3, in that order: normal period T1, medium-scale rough period T2, and large-scale rough period T3.

[0030] 7, the execution frequencies of the detection operation by the acceleration sensor 11 during the normal period T1, the medium-scale rough sea period T2, and the severe rough sea period T3 are P1, P2, and P3, respectively, and are lowest during the normal period T1 and highest during the severe rough sea period T3 (P1<P2<P3). In this embodiment, the execution frequencies P1, P2, and P3 are set to 60 minutes, 15 minutes, and 5 minutes, respectively, but are not limited to these and may be appropriately set for each sea area. For example, the execution frequency P1 is 60 to 120 minutes, the execution frequency P2 is 15 to 30 minutes, and the execution frequency P3 is 5 to 10 minutes.

[0031] During the normal period T1, the force acting on the marine hose 1 is relatively small, but this force acts repeatedly over a long period of time. Therefore, the cumulative force acting on the marine hose 1 during the normal period T1 significantly affects the degree of fatigue of the reinforcing cord. Therefore, in order to more accurately grasp the degree of fatigue of the reinforcing cord, the execution frequency P1 of the detection operation by the acceleration sensor 11 is not set too low during the normal period T1, and the control unit 13 controls the detection operation to be performed at intervals of 120 minutes or less. In other words, the execution frequency P1 is set to 120 minutes or less.

[0032] An example of a procedure for determining the degree of fatigue of the reinforcing cords that make up the marine hose 1 using this management system will now be described.

[0033] 1 and 2, a detection unit 10 is installed on a marine hose 1, and acceleration is detected by an acceleration sensor 11 with a sampling frequency set to 100 Hz or more and 200 Hz or less. Data D detected by the acceleration sensor 11 is sequentially stored and accumulated in a memory unit 12. The magnitude of acceleration in each piece of detection data D is sequentially compared with a first threshold value and a second threshold value by a control unit 13.

[0034] As illustrated in Figure 7, when the magnitude of acceleration in the detection data D is equal to or less than the first threshold (normal period T1), the control unit 13 controls the acceleration sensor 11 to perform a one-minute detection operation at an execution frequency P1 (60 minutes / time). When the magnitude of acceleration in the detection data D exceeds the first threshold and is equal to or less than the second threshold (medium-scale roughness period T2), the control unit 13 controls the acceleration sensor 11 to perform a detection operation at an execution frequency P2 (15 minutes / time). When the magnitude of acceleration in the detection data D exceeds the second threshold (large-scale roughness period T3), the control unit 13 controls the acceleration sensor 11 to perform a one-minute detection operation at an execution frequency P3 (5 minutes / time). Note that the acceleration during periods when the acceleration sensor 11 is not performing a detection operation (between detection operations) can be estimated and supplemented based on the detection data D from the detection operations performed before and after that period.

[0035] At predetermined times, such as once a year or every six months, after the start of the detection operation by the acceleration sensor 11 described above, the memory 12 in which the detection data D is accumulated is removed from the detection unit 10, and the detection data D accumulated in this memory 12 is input to the arithmetic device 16. After the memory 12 is removed from the detection unit 10, the accumulated detection data D is copied or transferred and then this memory 12 is attached to the arithmetic device 16, or a new memory 12 is attached to the arithmetic device 16, and new detection data D continues to be stored and accumulated in the same manner.

[0036] The computing device 16 calculates the degree of fatigue of the reinforcing cords constituting the marine hose 1 based on each piece of detection data D stored in the memory unit 12. Each piece of detection data D indicates the magnitude and state of the force acting on the marine hose 1 during the period in which that detection data D was detected. As described above, the acceleration sensor 11 performs each detection operation for a predetermined short time, and the sampling frequency of the detection data D is set to 100 Hz or more and 200 Hz or less. The detection operation is performed more frequently in the order of normal period T1, medium-scale rough weather period T2, and large-scale rough weather period T3, and the detection operation is performed at intervals of 120 minutes or less during the normal period T1. Therefore, a sufficient amount of detection data D useful for estimating the degree of fatigue of the reinforcing cords is obtained while suppressing power consumption of the battery 15.

[0037] It is believed that the greater the cumulative magnitude of the detection data D (acceleration), the more fatigued the reinforcement cord is. Therefore, the degree of fatigue of the reinforcement cord can be calculated based on the cumulative magnitude of the detection data D (acceleration). This is advantageous for accurately estimating the degree of fatigue of the reinforcement cord while saving power. As a result, the replacement timing of the marine hose 1 can be appropriately determined depending on the usage conditions of the marine hose 1. In other words, the marine hose 1 can be used without exceeding or falling short of the fatigue limit (service life) of the reinforcement cord for each usage condition of the marine hose 1, preventing the wasteful disposal of a marine hose 1 that still has sufficient usable life.

[0038] Furthermore, since it is possible to avoid increasing the size of the battery 15, this is advantageous in preventing the battery 15 (detection unit 10) from colliding with floating objects or an adjacent marine hose and being damaged, or from falling off the marine hose 1. Even though a small battery 15 is used, it is possible to operate the detection unit 10 for as long as possible with the battery 15. Furthermore, the degree of fatigue of the reinforcement cord can be easily calculated using the detection unit 10 and the computing device 16.

[0039] The detected data D can be used to calculate the degree of fatigue of the reinforcing cords using various methods, but for example, the data shown in Figures 8 and 9 are used. Figure 8 shows the results of a bending test in which a test sample of the marine hose 1 (a small-diameter hose) was repeatedly bent. The vertical axis represents the curvature when the hose is bent, and the horizontal axis represents the number of bends N until the hose (the reinforcing cords that make up the hose) reaches its fatigue limit. Figure 8 is a semi-logarithmic graph in which the common logarithm of the number of bends N is used as the scale on the horizontal axis. In this way, the relationship between the curvature and the number of bends N when the marine hose 1 is repeatedly bent is grasped in advance.

[0040] FIG. 9 shows the relationship between the exercise intensity S of the marine hose 1 and the exercise time M until the reinforcing cords constituting the marine hose 1 reach their fatigue limit. FIG. 9 is a semi-logarithmic graph using the common logarithm of the exercise time M as the horizontal axis scale. This exercise intensity S represents the degree of movement of the marine hose 1 and can be equated with the magnitude of the detected data D (acceleration). For example, known dynamic analysis software for the behavior of the marine hose 1 is used to understand the correlation between the exercise intensity S of the marine hose 1 and the hose curvature in the bending test shown in FIG. 8 and calculate the data shown in FIG. 9. From the data shown in FIG. 9, the exercise time M until the reinforcing cords reach their fatigue limit can be estimated using the exercise intensity S calculated based on the detected data D. That is, the exercise time M until the reinforcing cords reach their fatigue limit at each exercise intensity S is determined. The higher the exercise intensity S, the shorter the exercise time M until the reinforcing cords reach their fatigue limit, and the lower the exercise intensity S, the longer the exercise time M until the reinforcing cords reach their fatigue limit.

[0041] Of the three periods T1, T2, and T3, the exercise intensity S in period T1 is the lowest. Therefore, using the exercise intensity S (exercise time M) for one hour in period T1 as a reference, the exercise time M for one hour in period T2 can be converted as ka times (e.g., 2,500 times) the exercise time M for one hour in period T1. Similarly, the exercise time M for one hour in period T3 can be converted as kb times (e.g., 10,000 times) the exercise time M for one hour in period T1. As illustrated in FIG. 10 , the cumulative exercise time is calculated by accumulating the exercise time M for period T1 and the exercise times M (converted exercise times) for periods T2 and T3 converted based on the exercise intensity S (exercise time M) for one hour in period T1. This cumulative exercise time indicates the fatigue state of the reinforcing cords constituting the marine hose 1 at that time. The useful life of the marine hose 1 is reached when the reinforcing cords reach their fatigue limit, so the time to replace the marine hose 1 is set slightly before the useful life expires. By determining the replacement timing of the marine hose 1 in this manner, it becomes possible to use the marine hose 1 effectively without exceeding or deficient the fatigue limit of the reinforcing cord, even if the marine hose 1 is used under various different conditions.

[0042] The embodiment of the management system illustrated in Fig. 11 is substantially the same as the previous embodiment except that a transmitter 14 is added to the detection unit 10 of the previous embodiment and a communicator 17 is provided that is installed outside the marine hose 1. The storage unit 12 can be a memory that is detachable from the detection unit 10, or a memory that is not detachable from the detection unit 10.

[0043] The transmitter 14 wirelessly transmits the detection data D stored in the memory 12 to the communicator 17. The detection data D wirelessly transmitted to the communicator 17 is input to the arithmetic unit 16. If power from the battery 15 is used to transmit the detection data D from the communicator 17 from the transmitter 14, the power saving effect will be reduced. Therefore, it is preferable to use a known passive type transmitter 14.

[0044] The communicator 17 transmits outgoing radio waves R1 to the passive transmitter 14. The transmitter 14 generates power from the received outgoing radio waves R1 and uses this power to transmit reply radio waves R2 to the communicator 17. The reply radio waves R2 are received by the communicator 17, and wireless communication is performed between the transmitter 14 and the communicator 17. The detection data D stored in the memory 12 is transmitted from the transmitter 14 to the communicator 17 together with the reply radio waves R2.

[0045] For example, an operator approaching the marine hose 1 (detection unit 10) by boat operates the communicator 17 to communicate wirelessly between the transmitter 14 and the communicator 17. Alternatively, the communicator 17 can be mounted on a drone and brought close to the marine hose 1 (detection unit 10) to communicate wirelessly between the transmitter 14 and the communicator 17. By using a passive transmitter 14 in this manner, it is possible to ensure power saving effects for the battery 15 while reducing the labor required to acquire the detection data D stored in the memory unit 12 from the detection unit 10. In this embodiment, the various configurations described in the previous embodiments can also be employed.

[0046] REFERENCE SIGNS LIST 1 Marine hose 1a Flow path 2 Connecting fitting 2a Flange 2b Nipple 2c Fixing ring 3 Inner surface layer 4 First reinforcing layer 4w Nipple wire 5 Main body wire layer 5w Nipple wire 6 Second reinforcing layer 6w Nipple wire 7 Fluid retention layer 8 Buoyancy layer 9 Outer surface layer 10 Detection unit 11 Acceleration sensor 12 Memory unit 13 Control unit 14 Transmitter 15 Battery 16 Calculating device 17 Communication device

Claims

1. A marine hose management system comprising a detection unit installed on a marine hose and a computing device installed outside the marine hose, wherein the detection unit has an acceleration sensor, a memory unit for storing detection data from the acceleration sensor, a control unit for controlling the acceleration sensor, and a battery for providing power to components of the detection unit, wherein the detection operation by the acceleration sensor is set to a predetermined short time in advance, and the sampling frequency of the detection data by the acceleration sensor is set to between 100 Hz and 200 Hz, a marine hose management system configured such that the magnitude of acceleration in the detection data is divided into a normal period where the magnitude of acceleration is equal to or less than a first threshold, a medium-scale roughness period where the magnitude of acceleration exceeds the first threshold and is equal to or less than a second threshold, and a large-scale roughness period where the magnitude of acceleration exceeds the second threshold, the detection operation is executed more frequently in each period in the order of the normal period, the medium-scale roughness period, and the large-scale roughness period, and the detection operation is executed at intervals of 120 minutes or less in the normal period, and the arithmetic device is able to determine the degree of fatigue of the reinforcing cords that make up the marine hose based on the detection data stored in the memory unit.

2. A marine hose management system according to claim 1, wherein the magnitude of the second threshold acceleration is set to be between two and four times the magnitude of the first threshold acceleration.

3. A marine hose management system as described in claim 1 or 2, wherein a memory that is detachable from the detection unit is used as the storage unit, the memory in which the detection data is stored is detached from the detection unit at a predetermined time, and the detection data stored in the memory is input to the arithmetic device.

4. A marine hose management system as described in any one of claims 1 to 3, wherein the detection unit has a transmitting unit that wirelessly transmits the detection data stored in the memory unit to a communication device outside the marine hose, and the detection data wirelessly transmitted to the communication device is input to the arithmetic device.

5. A marine hose management method using a detection unit installed on the marine hose and a computing device installed outside the marine hose, wherein the detection unit is equipped with an acceleration sensor, a memory unit that stores detection data from the acceleration sensor, a control unit that controls the acceleration sensor, and a battery that serves as a power source for the components of the detection unit, wherein the duration of each detection operation by the acceleration sensor is set to a predetermined short time in advance, and the sampling frequency of the detection data by the acceleration sensor is set to between 100 Hz and 200 Hz, and the magnitude of acceleration in the detection data is divided into a normal period where the magnitude of acceleration is equal to or less than a first threshold, a medium-scale roughness period where the magnitude of acceleration in the detection data is above a first threshold and equal to or less than a second threshold, and a large-scale roughness period where the magnitude of acceleration in the detection data is above the second threshold, and the detection operation is performed more frequently in each of the normal periods, the medium-scale roughness period, and the large-scale roughness period in that order, and the control unit controls the detection operation to be performed at intervals of 120 minutes or less during the normal periods, and the computing device determines the degree of fatigue of the reinforcing cords that make up the marine hose based on the detection data stored in the memory unit.

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