KR102185713B1 - Method and system for managing ship - Google Patents

Abstract

A ship management method according to an embodiment of the present invention includes the steps of detecting a draft condition of a ship, setting a first reference temperature based on the draft condition, and a bush mounted at the rear of the ship. And outputting a warning alarm if the bush temperature detected at) is equal to or higher than the first reference temperature.

Description

Ship management method and system {METHOD AND SYSTEM FOR MANAGING SHIP}

The present invention relates to a ship management method and system.

A propeller to propel the ship is provided at the stern of the ship, and the propeller may be connected to a shaft capable of rotating motion. The shaft is connected to the engine and rotates to generate propulsion by rotating the propeller, and a bush for supporting the weight of the propeller may be installed in at least a portion of the shaft. The bush is usually provided in a cylindrical shape surrounding the shaft, and the shaft penetrates the space inside the bush. When the shaft is bent by the weight of the propeller, the shaft or bush is caused by friction between the shaft and the bush during rotational motion. There may be a problem that the back is damaged.

One of the problems to be achieved by the technical idea of the present invention is to detect a low draft condition in which the shaft is liable to bend by the weight of the propeller and output a warning alarm to the ship manager, etc., so that the shaft and/or bush, etc. It is to provide a ship management method and system that can prevent damage in advance.

A ship management method according to an embodiment of the present invention includes the steps of detecting a draft condition of a ship, setting a first reference temperature based on the draft condition, and a bush mounted at the rear of the ship. And outputting a warning alarm if the bush temperature detected at) is equal to or higher than the first reference temperature.

In some embodiments of the present invention, the setting step may set a second reference temperature higher than the first reference temperature.

In some embodiments of the present invention, when the bush temperature increases above the second reference temperature after outputting the warning alarm, the step of automatically lowering the rotation speed of the propeller connected to the bush may be further included.

In some embodiments of the present invention, if the bushing temperature increases above the second reference temperature after outputting the warning alarm, the method further includes automatically lowering a rotational speed of a propeller connected to the bush to stop the propeller. can do.

In some embodiments of the present invention, the draft condition may be detected by comparing the average value of the draft measured for a predetermined time with a predetermined reference draft.

In some embodiments of the present invention, if the average value of the draft is less than or equal to the reference draft, the draft condition may be determined as a low draft condition.

In some embodiments of the present invention, when the average value of the draft is less than or equal to the reference draft, the first reference temperature is determined as a first value, and the second reference temperature is determined as a second value greater than the first value, and If the average value of the draft is greater than the reference draft, the first reference temperature may be determined as a third value greater than the first value, and the second reference temperature may be determined as a fourth value greater than the third value. .

In some embodiments of the present invention, if the average value of the draft is less than or equal to the reference draft, the step of outputting a Low Draft notification to the ship's manager may be further included.

In some embodiments of the present invention, if the amount of change per unit time of the bushing temperature is equal to or greater than a predetermined first reference amount of change, outputting the warning alarm is further included.

In some embodiments of the present invention, if the change per unit time of the bush temperature is greater than or equal to the second reference change amount greater than the first reference change amount after the warning alarm is output, automatically lowering the rotation speed of the propeller connected to the bush. It includes more.

In the ship management system according to an embodiment of the present invention, a propeller of a ship is connected to a first end, and a second end other than the first end is a shaft connected to the engine of the ship, and surrounds and supports the shaft. Bush and the first reference temperature and the second reference temperature are set based on the draft condition of the ship, and the bush temperature detected in the bush when the ship operates in a low draft condition And a control device for outputting a warning alarm when is greater than the first reference temperature.

In some embodiments of the present invention, the second reference temperature is higher than the first reference temperature, and the first reference temperature and the second reference temperature may have different values according to the draft condition.

In some embodiments of the present invention, the control device may lower the rotational speed of the shaft or stop the rotational motion of the shaft when the bushing temperature increases above the second reference temperature after outputting the warning alarm. I can.

In some embodiments of the present invention, the control device may detect heat generated due to friction between the bush and the shaft as the shaft is bent under the low draft condition, as the bush temperature.

In some embodiments of the present invention, the control device may detect the draft condition by comparing the average value of the draft measured for a predetermined time with a predetermined reference draft.

In some embodiments of the present invention, when the average value of the draft is less than or equal to the reference draft, the control device may determine the draft condition as a low draft condition and output a low draft notification.

In some embodiments of the present invention, when the average value of the draft is greater than the reference draft, the control device sets each value of the first reference temperature and the second reference temperature, compared to when the average value of the draft is less than or equal to the reference draft. It can be set smaller.

According to an embodiment of the present invention, a predetermined reference temperature is set according to a draft condition of a ship, and a bush temperature detected in a bush surrounding a shaft connected to a propeller is compared with the reference temperature to output a warning alarm, or It is possible to reduce the rotational speed of the shaft. Accordingly, it is possible to effectively prevent damage to the shaft and/or the bush that may occur due to friction between the shaft and the bush in a low draft condition where the shaft is easily bent by the weight of the propeller.

The various and beneficial advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the course of describing specific embodiments of the present invention.

1 is a schematic view showing the stern structure of a ship according to an embodiment of the present invention.
2 and 3 are views provided to explain the bending phenomenon of the shaft that may occur in the ship according to an embodiment of the present invention.
4 is a view showing a result of a simulation predicting a load applied to a bush when a shaft is bent in a ship according to an embodiment of the present invention.
5 is a schematic block diagram of a ship management system according to an embodiment of the present invention.
6 and 7 are views provided to explain a ship management method according to an embodiment of the present invention.
8 and 16 are diagrams showing results of simulations performed to explain a ship management method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a schematic view showing the stern structure of a ship according to an embodiment of the present invention.

1, a stern portion of a ship 10 according to an embodiment of the present invention includes a ship body 11, a propeller 12, a shaft 13, and a bush (14-15, Bush), etc. Can include. The shaft 13 extends in one direction (the X-axis direction of FIG. 1), and may be connected to the propeller 12 at one end in the one direction, and connected to the engine at the other end. When the engine is driven, the propeller 12 rotates by the shaft 13 to generate a thrust, and the ship 10 may move forward by the thrust.

The bush 14-15 may have a cylindrical shape surrounding at least a portion of the shaft 13, and may support the shaft 13 while the propeller 12 and the shaft 13 are rotated by the engine. . The bush 14-15 may include a first bush 14 disposed close to the propeller 12 and a second bush 15 disposed relatively close to the engine. Accordingly, the shaft 13 and the first bush 14 or the shaft 13 and the second bush 15 may come into contact with each other due to the weight of the propeller 12 or vibration generated during rotational movement. In this case, the shaft Due to the rotation of (13), wear or damage may occur in the shaft 13 and/or the first bush 14, the second bush 15, and the like.

Such contact may occur mainly between the shaft 13 and the first bush 14, and may occur when the shaft 13 is bent by the load of the propeller 12 mounted at one end of the shaft 13 . In particular, the propeller 12 is not completely submerged in water draft When the ship 10 operates in the (Low Draft) condition, the load of the propeller 12 is strongly applied to the shaft 13 so that the shaft 13 can be easily bent. Therefore, low draft Under conditions, when the ship 10 runs for a long time or runs at a high speed, the possibility of damage to the shaft 13 and/or the first bush 14 may increase.

Work of the present invention In the example , In order to solve the above problems, the ship 10 is low draft When operating under conditions, the bush temperature may be detected by the first bush 14 and the bush temperature may be compared with a predetermined reference temperature. When the bushing temperature increases above the reference temperature, it is possible to prevent damage to the shaft 13 and/or the first bush 14 by outputting a warning alarm or by lowering the driving speed of the engine rotating the shaft 13. have.

2 and 3 are views provided to explain the bending phenomenon of the shaft that may occur in the ship according to an embodiment of the present invention.

First, the exemplary embodiment shown in FIG. 2(a) may correspond to a case where the shaft 13 is not bent by the load of the propeller 12. Therefore, while the engine is operating and the propeller 12 and the shaft 13 rotate, contact between the shaft 13 and the bush 14 may not occur, and as a result, heat generated by friction in the bush 14 Occurs or the bush 14 may not be damaged.

FIG. 2(b) may be a graph showing an action point of thrust generated by rotation of the propeller 12 in the embodiment shown in FIG. 2(a). In the graph of FIG. 2(b), the origin where the Y-axis and the Z-axis intersect may correspond to the rotation axis of the propeller 12 viewed from the Y-Z axis. When the shaft 13 is not bent by the propeller 12, the thrust acting point of the propeller may be defined as the first point 20 located above the Y axis. For example, when the ship 10 operates under a draft condition in which the propeller 12 is sufficiently immersed in water, a thrust action point may appear as shown in FIG. 2(b).

Next, the embodiment shown in FIG. 3(a) may correspond to the case where the shaft 13 is bent by the load of the propeller 12. Therefore, while the engine is operating and the propeller 12 and the shaft 13 rotate, the shaft 13 and the bush 14 contact each other, and heat generation due to friction may occur in the shaft 13 and the bush 14. As a result, the shaft 13 and/or the bush 14 may be damaged. In particular, when the ship 10 operates in a low draft condition in which the load of the propeller 12 is concentrated on the shaft 13, a problem as shown in FIG. 3(a) may easily appear.

As shown in Figure 3 (a), when the shaft 13 is bent by the load of the propeller 12, the contact surface 15 of the shaft 13 and the bush 14 is adjacent to the propeller 12 It can occur at the end of the bush 14. When the ship 10 operates for a long time and/or at high speed while the shaft 13 and the bush 14 are in contact, the inner surface of the bush 14 or the shaft 13 is damaged, resulting in a large repair cost and repair period. Can cause.

3(b) may be a graph showing an action point of a thrust generated by rotation of the propeller 12 in the exemplary embodiment shown in FIG. 3(a). As in FIG. 2(b), the origin at which the Y-axis and the Z-axis intersect in the graph of FIG. 3(b) may correspond to the rotation axis of the propeller 12 viewed from the Y-Z axis. When the shaft 13 is bent by the propeller 12, the thrust action point of the propeller may be defined as the second point 30 located below the Y axis, not the first point 20 located above the Y axis. have. For example, when the ship 10 operates in a low draft condition in which the propeller 12 is not sufficiently submerged in water, a thrust action point may appear as shown in FIG. 3(b).

4 is a view showing a result of a simulation predicting a load applied to a bush when a shaft is bent in a ship according to an embodiment of the present invention.

As an example, FIG. 4 may correspond to a result of a simulation in which a load applied to a bush is predicted assuming a condition in which the shaft is bent and the thrust acting point of the propeller is located below the horizontal axis. Referring to FIG. 4, in the bush having a cylindrical shape, a high load may be applied to a portion close to the propeller. Depending on the position of the bush, the load applied can vary from several times to tens of thousands of times or more.

If the rotational motion of the bent shaft continues, the oil film existing between the inner surface of the bush and the outer peripheral surface of the shaft may be destroyed. After the oil film is destroyed, the inner surface of the bush and the outer circumferential surface of the shaft may be in direct contact, and thus, problems such as abrasion of the inner surface of the bush due to the rotational motion of the shaft, or damage to the inner surface of the bush may occur.

For example, when the ship is operated at low draft conditions and the propeller is locked by only about 60%, when the ship is operated at a high speed, high heat of about 70 degrees or more may be generated due to contact between the bush and the shaft. This may be a temperature sufficient to destroy the oil film existing between the bush and the shaft and damage the bush itself by contact between metals.

In an embodiment of the present invention, when a ship operates in a low draft condition, the bushing temperature may be detected from the bush, and the bushing temperature may be compared with a predetermined reference temperature. When the bushing temperature increases above the reference temperature, a warning alarm is output to the ship's manager or the like, or by automatically lowering the rotation speed of the shaft by the engine, other damage to the contact between the shaft and the bush can be effectively prevented. In addition, according to embodiments, it is possible to determine a warning alarm output and shaft rotation speed adjustment by comparing an increase amount of the bush temperature with a predetermined reference increase amount.

5 is a schematic block diagram of a ship management system according to an embodiment of the present invention.

Referring to FIG. 5, the ship management system 100 according to an embodiment of the present invention may include a sensor unit 110 and a control device 120. The sensor unit 110 may include a temperature sensor connected to a bush that surrounds and supports at least a portion of the shaft at the ship's stern. The control device 120 may be implemented as a computer device, and the temperature sensor of the sensor unit 110 may acquire a bush temperature detected from the bush. For example, the control device 120 may acquire the bushing temperature at every predetermined period, and the period may be long or short depending on the draft condition of the ship. For example, as the draft of the ship is smaller, the control device 120 may frequently obtain the bush temperature from the sensor unit 110.

The control device 120 may compare the bush temperature with a predetermined reference temperature. The reference temperature may have different sizes depending on the draft condition of the ship. The control device 120 may set the reference temperature to a smaller value when the vessel operates in a low draft condition. Alternatively, the reference temperature may be determined in inverse proportion to the vessel's draft value.

In an embodiment, the control device 120 may set a first reference temperature and a second reference temperature. The second reference temperature may be greater than the first reference temperature, and the control device 120 may sequentially compare the bush temperature with the first reference temperature and the second reference temperature. When the bush temperature is greater than the first reference temperature, the control device 120 may output a warning alarm to the ship's manager, etc., to notify that there is a possibility that damage may occur in the shaft and/or bush. Even after outputting the warning alarm, if the bush temperature continues to rise and becomes greater than the second reference temperature, the control device 120 automatically slows down or stops the engine, thereby lowering or stopping the rotational speed of the shaft, and It can prevent breakage.

6 and 7 are views provided to explain a ship management method according to an embodiment of the present invention.

First, referring to FIG. 6, the ship management method according to an embodiment of the present invention may begin with the control device detecting the draft condition of the ship (S10). For example, the control device may determine the draft condition of the ship by comparing the draft detected by the ship with a predetermined reference value. When the draft detected by the ship is less than the reference value, the control device may determine that the ship is operating in a low draft condition.

The control device may set the first reference temperature based on the draft condition detected in step S10 (S20). As described above, when it is determined that the vessel is operating under a low draft condition, the control device can lower the size of the first reference temperature, and if the vessel is not operating under a low draft condition, the magnitude of the first reference temperature is increased. I can make it. In addition, according to embodiments, the first reference temperature may be determined differently according to the actually measured draft even in a low draft condition. For example, the smaller the measured draft, the smaller the size of the first reference temperature may be determined.

The control device may detect the bushing temperature from the bush (S30) and compare the detected bushing temperature with the first reference temperature. If the bush temperature is higher than the first reference temperature, the control device may output a warning alarm to the ship's manager (S40). Accordingly, the ship's manager can quickly catch and cope with the contact and friction between the shaft and the bush, thereby minimizing the possibility of damage to the shaft and/or bush.

Next, referring to FIG. 7, the ship management method according to an embodiment of the present invention may begin with the control device measuring the draft of the ship for a predetermined time (S101). The control device may calculate an average value of the draft of the vessel measured for a certain time, and compare the average value with a predetermined reference draft (S102). As in steps S101 and S102, by comparing the average value of the measured draft for a certain time with the reference draft, the draft condition of the ship can be more accurately detected. For example, the control device may compare the average value of the measured draft over several minutes with the reference draft.

The control device may determine whether the average value calculated in step S102 is equal to or greater than the reference draft (S103). As a result of the determination in step S103, if the average value is greater than or equal to the reference draft, the control device may determine that the ship is operating in a low draft condition, and may output a low draft notification to the ship's manager (S104). Accordingly, the ship's manager may recognize the possibility of contact and friction between the shaft and the bush due to the weight of the propeller in advance by referring to the low draft notification output in step S104, and reduce the sailing speed of the ship.

Meanwhile, the control device may determine the first reference temperature as the first value and the second reference temperature as the second value (S105). For example, the second value may be greater than the first value. On the other hand, if it is determined that the average value is smaller than the reference draft in step S103, the first reference temperature may be determined as a third value and the second reference temperature may be determined as a fourth value (S106). The fourth value may be greater than the third value, and for example, the third value may be greater than the second value. However, the size and magnitude relationship of the first to fourth values may be variously modified in consideration of the material of the shaft and the bush, and the amount of heat generated by friction between the shaft and the bush.

The control device may compare the bushing temperature with the first reference temperature (S107). If it is determined in step S107 that the bush temperature is less than the first reference temperature, the control device determines that there is no or less possibility of damage to the shaft and/or bush, and may measure the draft of the ship again. On the other hand, if it is determined that the bush temperature is equal to or higher than the first reference temperature in step S107, the control device may determine that there is a possibility of damage to the shaft and/or bush and output a warning alarm (S108). The ship's manager can prevent damage to the shaft and/or the bush by lowering the operating speed of the ship or stopping the ship in response to the warning alarm output in step S108.

After outputting the warning alarm, the control device may compare the bush temperature with the second reference temperature (S109). For example, the control device may compare the bush temperature with the second reference temperature after a predetermined time has elapsed from the time when the warning alarm is output. As described above, the second reference temperature may be higher than the first reference temperature. Accordingly, it can be determined in step S109 whether the bush temperature is properly controlled by the action taken by the ship's manager in response to the warning alarm output in step S108.

If it is determined that the bushing temperature is lower than the second reference temperature as a result of the comparison in step S109, the control device may measure the draft of the ship again without any additional operation. On the other hand, if it is determined in step S109 that the bushing temperature is equal to or higher than the second reference temperature, the control device may determine that the bushing temperature has increased even though the warning alarm is output. Accordingly, the control device may forcibly slow or stop the operation of the engine, thereby reducing the rotation speed of the shaft or stopping the rotation of the shaft (S110).

In the ship management method according to an embodiment of the present invention, it is possible to determine whether to output a warning alarm by comparing the bush temperature detected by the bush of the ship with the first reference temperature. In addition, after the bushing temperature is determined to be higher than the first reference temperature and a warning alarm is output, the bushing temperature is compared with the second reference temperature again to determine whether the ship's manager recognizes the warning alarm and takes appropriate control measures. can do. If the detected bush temperature after outputting the warning alarm is determined to be abnormal in the second reference temperature, the control device may automatically intervene in the engine control of the ship to lower the rotation speed of the shaft or stop the rotation of the shaft. Accordingly, the shaft is bent by the load of the propeller and the rotational motion is continued in contact with the bush, thereby preventing the problem that the oil film is removed from the bush and heat is generated and the bush is damaged.

Meanwhile, in an embodiment of the present invention, the first reference temperature and the second reference temperature may be differently determined according to the draft condition of the ship. That is, by appropriately selecting the size of each of the first reference temperature and the second reference temperature according to the draft condition of the vessel, the vessel can be controlled under the optimum conditions.

8 to 16 are views showing results of simulations performed to explain a ship management method according to an embodiment of the present invention.

First, the exemplary embodiment illustrated in FIG. 8 may show the result of a simulation of detecting oil film and pressure of a bush when the ship is operating at full sailing speed (Nav. Full) under a draft condition in which the propeller of the ship is submerged by 75%. . The graph (a) of FIG. 8 shows the thickness of the oil film detected by the bush, and the graph (b) of FIG. 8 may be the detection of the pressure applied to the bush. For example, referring to the graph (a) of FIG. 8, the thickness of the oil film may be 10 μm or less in a region where contact between the shaft and the bush may occur. In addition, referring to the graph (b) of FIG. 8, a maximum pressure of 450 bar or more may be applied to the bush in a region where contact between the shaft and the bush may occur.

In other words, if only 75% of the propellers are operated at full speed of the ship's voyage under the condition that only 75% of the propellers are submerged in water, there will be a point where a sufficient oil film is not formed between the bush and the shaft and excessive pressure is applied to the bush by the contact between the shaft and the bush. I can. For example, the minimum thickness of the oil film required to prevent damage to the shaft and the bush may be defined as about 30 μm. Accordingly, the shaft and/or bush may be damaged by friction between the shaft and the bush, but damage of the shaft and/or bush may be prevented by applying the ship management method according to an embodiment of the present invention.

9 and 10 show the results of simulations of detecting oil film and pressure of the bush when the ship operates at half speed or dead slow in the port under a draft condition in which the propeller of the ship is submerged by 75%, respectively. Can be indicated. Like the exemplary embodiment illustrated in FIG. 8, in FIGS. 9 and 10, graph (a) shows the thickness of the oil film detected by the bush, and graph (b) may be the detection of pressure applied to the bush. First, referring to the graph (a) of FIG. 9, the minimum oil film thickness between the shaft and the bush may be about 10 μm, and the maximum pressure applied to the bush may be about 310 bar. Next, referring to graph (a) of FIG. 10, the minimum thickness of the oil film may be about 28 μm. Further, referring to the graph (b) of FIG. 10, a maximum pressure of about 95 bar may be applied to the bush in a region where contact between the shaft and the bush may occur.

That is, even under the same draft condition, the pressure applied to the bush and the minimum thickness of the oil film between the shaft and the bush may vary according to the operating speed of the ship. For example, as the sailing speed of the ship decreases, the contact position between the shaft and the bush may move away from the propeller, the pressure applied to the bush may decrease, and the minimum thickness of the oil film may increase. However, as shown in Figs. 8 to 10, under the condition that only 75% of the propeller is submerged in water, a sufficient oil film is not formed regardless of the sailing speed of the ship, and excessive pressure is applied to the bush due to the contact between the shaft and the bush. A point of application can occur. For example, the minimum thickness of the oil film required to prevent damage to the shaft and the bush may be defined as about 30 μm. Accordingly, the shaft and/or bush may be damaged by friction between the shaft and the bush, but damage of the shaft and/or bush may be prevented by applying the ship management method according to an embodiment of the present invention.

Next, the embodiments shown in FIGS. 11 to 13 are simulations of detecting oil film and pressure of the bush when the ship operates at full sailing speed, half speed in port, and lowest speed in port under a draft condition in which the propeller of the ship is submerged by 50%. Can represent the result of. In each of FIGS. 11 to 13, graph (a) shows the thickness of the oil film detected by the bush, and graph (b) may be the detection of pressure applied to the bush.

Compared with the embodiments shown in FIGS. 8 to 10, the embodiments shown in FIGS. 11 to 13 may correspond to a case where the draft of the ship is smaller. Accordingly, a relatively large load of the propeller may be applied to the shaft, the thickness of the oil film between the shaft and the bush may decrease, or the pressure applied to the bush by the shaft may increase. For example, in the embodiments shown in FIGS. 11 to 13, the minimum thickness of the oil film may be all about 10 μm regardless of the sailing speed of the ship. This is a value that is less than the minimum thickness of the oil film required to prevent damage to the shaft and the bush, and thus the shaft and/or the bush may be damaged if the ship is running for a long time.

In addition, when the vessel operates at full speed, half speed in port, and lowest speed in port, respectively, the maximum pressure received by the bush can be measured at about 850 bar, 330 bar, and 130 bar, respectively. That is, when compared with the graphs of FIGS. 8 to 10 that assume a draft condition in which the propeller is submerged by 75%, the pressure received by the bush increases, and thus the possibility of damage to the shaft and/or bush may increase. In order to solve the above problems, a ship management method according to an embodiment of the present invention may be applied, and damage to the shaft and/or bush may be prevented.

Next, the embodiments shown in FIGS. 14 to 16 are simulations that detect oil film and pressure of the bush when the ship operates at full sailing speed, half speed in port, and lowest speed in port under a draft condition in which the propeller of the ship is submerged by 25%. Can represent the result of. In each of FIGS. 14 to 16, graph (a) shows the thickness of the oil film detected by the bush, and graph (b) may be the detection of pressure applied to the bush.

Like the embodiments of FIGS. 8 to 13 described above, in the embodiments shown in FIGS. 14 to 16, an oil film is not formed to have a sufficient thickness between the shaft and the bush, and excessive pressure may be applied to the bush. 14 to 16, the minimum thickness of the oil film is about 10 μm when the ship operates at full speed and half speed in the port, and the minimum thickness of the oil film is about 24 μm when the ship operates at the lowest speed in the port. Can be. When the vessel operates at the lowest speed in the port, the minimum thickness of the oil film increases somewhat, but this may be less than the minimum thickness of the oil film required for stable operation. For example, as described above, the minimum thickness of the oil film required for stable operation may be defined as about 30 μm.

In addition, when the vessel operates at the full voyage speed, the half speed in the port, and the lowest speed in the port, respectively, the maximum pressure received by the bush can be measured at about 170 bar, 150 bar, and 110 bar, respectively. Since the maximum pressure as described above is applied to the bush in an oil film state in which the minimum thickness required for stable operation is not secured, the shaft and/or the bush may be easily damaged. In order to solve the above problems, a ship management method according to an embodiment of the present invention may be applied, and damage to the shaft and/or bush may be prevented.

As described with reference to FIGS. 8 to 16, if all of the propellers are not submerged in water, the oil film between the shaft and the bush may not have a sufficient thickness, which is due to an increase in calorific value due to friction between the shaft and the bush. Can lead. In addition, in addition to the amount of heat generated, the shaft and/or the bush may be damaged due to an impact caused by friction between the shaft and the bush.

As described above, in an embodiment of the present invention, the size of the first reference temperature and the second reference temperature may be determined by detecting a draft condition of a ship that is related to the degree to which the propeller is submerged, and the bush detected by the bush The temperature may be sequentially compared with the first reference temperature and the second reference temperature. For example, the second reference temperature may be greater than the first reference temperature.

When the bushing temperature is higher than the first reference temperature, a warning alarm for notifying the possibility of damage to the shaft and/or bush may be output. If a predetermined time elapses after the warning alarm is output, the bushing temperature is detected again and compared with the second reference temperature. I can judge. Accordingly, when the bushing temperature is higher than the second reference temperature, the control device of the ship can effectively prevent damage to the shaft and/or bush by forcibly stopping the operation of the ship engine or lowering the operating speed.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited by the appended claims. Therefore, various types of substitutions, modifications and changes will be possible by those of ordinary skill in the art within the scope not departing from the technical spirit of the present invention described in the claims, and this also belongs to the scope of the present invention. something to do.

10: ship
11: ship body
12: propeller
13: shaft
14: bush

Claims (17)

Detecting a draft condition of the ship;
Setting a first reference temperature based on the draft condition; And
Outputting a warning alarm when a bush temperature detected by the first bush among the first bush mounted at the rear of the ship and disposed close to the propeller and the second bush disposed close to the engine is higher than the first reference temperature; Including,
A ship management method in which the period for acquiring the bush temperature is adjusted according to the draft condition of the ship.
The method of claim 1,
In the setting step, the ship management method of setting a second reference temperature higher than the first reference temperature.
The method of claim 2,
Automatically lowering a rotation speed of a propeller connected to the bush when the bushing temperature increases above the second reference temperature after outputting the warning alarm; Ship management method further comprising a.
The method of claim 3,
When the bush temperature increases above the second reference temperature after outputting the warning alarm, automatically lowering a rotation speed of a propeller connected to the bush to stop the propeller; Ship management method further comprising a.
The method of claim 2,
A ship management method for detecting the draft condition by comparing the average value of the draft measured for a certain time with a predetermined reference draft.
The method of claim 5,
If the average value of the draft is less than or equal to the reference draft, the ship management method of determining the draft condition as a low draft condition.
The method of claim 5,
If the average value of the draft is less than or equal to the reference draft, the first reference temperature is determined as a first value, and the second reference temperature is determined as a second value greater than the first value,
When the average value of the draft is greater than the reference draft, the first reference temperature is determined as a third value greater than the first value, and the second reference temperature is determined as a fourth value greater than the third value. Way.
The method of claim 5,
If the average value of the draft is less than the reference draft, outputting a Low Draft notification to the ship's manager; Ship management method further comprising a.
The method of claim 1,
Outputting the warning alarm when the amount of change per unit time of the bushing temperature is greater than or equal to a predetermined first reference change amount; Ship management method further comprising a.
The method of claim 9,
Automatically lowering a rotational speed of a propeller connected to the bush if the amount of change per unit time of the bush temperature is greater than or equal to a second reference change amount greater than the first reference change amount after the warning alarm is output; Ship management method further comprising a.
The propeller of the ship is connected to the first stage, and the second stage other than the first stage is connected to the engine of the ship, and at least a portion of the area is mounted at the rear of the ship and is placed close to the propeller. A shaft supported by a bush including a second bush disposed close together;
A sensor unit detecting a bush temperature from the first bush; And
A control that sets a first reference temperature and a second reference temperature based on the draft condition of the vessel, and outputs a warning alarm when the vessel operates under a low draft condition and the bush temperature is greater than the first reference temperature Device; Including,
The control device is a vessel that adjusts the period of acquiring the bushing temperature according to the draft condition of the vessel.
The method of claim 11,
The second reference temperature is higher than the first reference temperature,
The control device determines values of the first reference temperature and the second reference temperature according to the draft condition.
The method of claim 12,
The control device lowers the rotational speed of the shaft or stops the rotational motion of the shaft when the bushing temperature increases above the second reference temperature after outputting the warning alarm.

The method of claim 11,
The control device is a vessel that detects heat generated by friction between the bush and the shaft as the shaft is bent under the low draft condition, as the bush temperature.
The method of claim 11,
The control device detects the draft condition by comparing the average value of the draft measured for a predetermined time with a predetermined reference draft.
The method of claim 15,
When the average value of the draft is less than or equal to the reference draft, the control device determines the draft condition as a low draft condition and outputs a low draft notification.
The method of claim 16,
When the average value of the draft is greater than the reference draft, the control device sets each value of the first reference temperature and the second reference temperature to be smaller than when the average value of the draft is less than or equal to the reference draft.

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