JP2004354183A - Liquid level detection device and submergence alarm device of vessel equipped with sounding pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid level detection device and a submergence alarm device of a vessel equipped with a sounding pipe capable of reducing the installation number of detectors of the liquid level by utilizing the sounding pipe, and reducing peripheral equipment attached to the detectors. <P>SOLUTION: This liquid level detection device of the vessel is equipped with a differential pressure detector 5 mounted on a part on an upper deck of the sounding pipe 3 provided from on the upper deck toward the vessel bottom, for detecting the differential pressure of the sounding pipe 3, and an arithmetic unit 14 for determining the liquid level from the differential pressure detected by the differential pressure detector 5. In the arithmetic unit, the operated liquid level is compared with a set alarm level and an alarm signal is issued when the liquid level reaches the alarm level. In the alarm device, an alarm is sounded by the alarm signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid level detection device and a flood alarm device of a ship provided with a sounding tube for detecting a liquid level of water accumulated in a hold or a ballast tank in a ship such as a bulk carrier having a sounding tube.
[0002]
[Prior art]
Water is accumulated in the holds and ballast tanks due to rain from the deck openings, seawater impingement, grounding, etc. The liquid level of the accumulated water is detected by a water level gauge (liquid level gauge), and an alarm is issued when the detected liquid level reaches the alert level. As a method for detecting the liquid level, a pressure type, a float type, a capacitance type, an air purge type and the like are known. For example, Patent Literature 1 discloses an inundation warning device for a small boat that detects an inundation state with a float sensor and issues an alarm.
[0003]
FIG. 8 is a wiring diagram and an installation diagram of a conventional detector of a cargo ship. In each cargo hold 2 partitioned by a partition wall, a contact type level switch 15 is arranged for each of a plurality of levels from the ship bottom to the upper deck. When the alarm level switch 15 is turned on, an ON signal is transmitted to the alarm device of the bridge 6 via a signal line, and an alarm is issued.
[0004]
There is also a method in which a sounding pipe is provided from the upper deck to the bottom of the ship, and a sounding rod is lowered into the sounding pipe to detect the liquid level at a wet position of the rope.
[0005]
[Patent Document 1]
JP 2002-225789 A
[Problems to be solved by the invention]
Since the detector used in the flood warning device of the bulk carrier uses a contact type level switch, n detectors are required to detect a plurality of levels (for example, n locations). . Since a bulk carrier has a cargo hold of multiple sections (for example, m sections) divided by horizontal bulkheads, n × m detectors are required for the entire ship, and the liquid level is the water level from the bottom of the ship. Therefore, not only must the power supply and signal line cables be lowered from the upper deck to the lower part of the cargo hold to install detectors, but also the detector, power supply and signal line cables must be loaded and vibrated. However, there is a disadvantage that additional equipment is required and equipment cost is required. Further, since the detector detects seawater, oil, and sludge water of powder of cargo, there is a problem that corrosion resistance is required and periodic cleaning is required.
[0007]
In addition, since it is necessary to mount the detector on the service ship at the port of call where the cargo hold is empty, there is also a problem that the operation is stopped during the mounting period, so that wasteful costs are incurred.
[0008]
Therefore, the present invention provides a liquid level of a ship equipped with a sounding pipe, which can reduce the number of liquid level detectors to be installed by using a sounding pipe and reduce peripheral equipment attached to the detector. A level detecting device and a flood alarm device are provided.
[0009]
[Means for Solving the Problems]
A liquid level detection device for a ship according to the present invention is a differential pressure detector attached to a portion of a sounding tube provided on the upper deck from the upper deck to the bottom of the ship, for detecting a differential pressure of the sounding tube. And an arithmetic unit for obtaining a liquid level from the differential pressure detected by the differential pressure detector.
[0010]
Further, the inundation warning device for a ship according to the present invention is a differential pressure detector that detects a differential pressure of the sounding tube attached to a portion of the sounding tube provided on the upper deck from the upper deck toward the ship bottom. An arithmetic unit that calculates a liquid level from the differential pressure detected by the differential pressure detector, compares the calculated liquid level with a set alarm level, and issues an alarm signal when the liquid level reaches the alarm level. And an alarm device for issuing an alarm by an alarm signal.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a plan view showing an arrangement of the liquid level detecting device of the present invention, FIG. 2 is a sectional view in the same longitudinal direction, and FIG. 3 is a sectional view in the same width direction.
[0012]
A sounding pipe 3 for guiding a sounding rod extends from the upper deck to the bottom of the ballast tank 4 on each of the port side and the starboard side of the cargo hold 2 partitioned by the bulkhead 1. A differential pressure detector 5 is mounted on an upper part of the sounding tube 3 protruding from the upper deck. The detection signal detected by the differential pressure detector 5 is transmitted to the arithmetic unit of the bridge 6 by a communication line cable or wirelessly. As an example of the transmission of the detection signal, there is a polling method or the like that periodically calls each of the detectors 5 from the monitoring device in order.
[0013]
FIG. 4 is a diagram showing a connection portion between a differential pressure detector and a sounding pipe. In FIG. 4, the upper part of the sounding pipe 3 is closed by a lid 7, and the differential pressure detector 5 is connected to the sounding pipe 3 through a pipe 7 on the side for measuring the internal pressure of the sounding pipe 3, and the pressure difference is measured by opening the atmospheric pressure side. Detect pressure. As the differential pressure detector 5, a known differential pressure gauge (for example, Sursense manufactured by Honeywell Data Instruments Co., Ltd.) can be used. The differential pressure detected by the differential pressure detector 5 is converted into a signal by the converter 9, and a detection signal is transmitted from the communication terminal 10 by the antenna 11.
[0014]
FIG. 5 is a diagram showing the flow of the detection signal. A detection signal is transmitted from each of the slave stations 1 to 6 including the differential pressure detector 5, the converter 9, and the communication terminal 10 for each sounding tube. The transmitted signal is received by the antenna 13 of the communication terminal 12 serving as the master station of the bridge 6. The transmission and reception of the detection signal can be performed by wire. The detection signal received by the bridge 6 is subjected to data processing by the arithmetic unit 14 to calculate the liquid level.
[0015]
FIG. 6 is an explanatory diagram of the relationship between the differential pressure and the detection level. As the liquid level in the tank 4 rises due to the flooding, the liquid level in the sounding pipe 3 increases, and the differential pressure of the sounding pipe 3 also increases. The liquid level in the sounding pipe 3 is located below the liquid level in the tank 4 due to the internal pressure. Since the pressure difference of the sounding tube 3 and the liquid level in the tank 4 change in a proportional relationship as shown in the graph of FIG. 6B, the difference is obtained from the relationship between the pressure difference and the liquid level obtained in advance. The liquid level can be obtained by detecting the pressure.
[0016]
FIG. 7 is a diagram illustrating a change in the detection level. As shown in FIG. 7 (a), when the ship shakes and tilts due to the waves, the liquid level changes, and the differential pressure of the sounding pipe also changes. As a result, as shown in the detection level 1 of FIG. 7 (b). In addition, since the detection level also fluctuates, it is necessary to correct it. The correction is performed, for example, by calculating the average of the detection levels for a certain period of time by an arithmetic unit and setting the detection level as shown in FIG. 7 (c). Further, when the ship is tilted, as shown in FIG. Is different from the liquid level on the port side, the average of the detected level on the starboard side and the detected level on the port side is calculated by the arithmetic unit 14 of the bridge, and is used as the detection level in the horizontal state. The correction corrects not only for the inclination but also for the influence of the temperature. The level after the correction is obtained in advance and stored in the arithmetic unit.
[0017]
The liquid level in the tank 4 obtained by data processing by the arithmetic unit 14 is displayed on a bridge alarm display panel. The detection level is compared with the set alarm level. As a result of the comparison, when the alarm level is reached, an alarm signal is generated and an alarm is issued from the alarm device.
[0018]
【The invention's effect】
Since the present invention uses a sounding tube to determine the liquid level by differential pressure, the number of detectors to be installed is greatly reduced as compared to the conventional case where detectors are installed for each level in a cargo hold. I do. Further, since the detector is provided on the upper deck, signal cables and power supply lines in the cargo hold, and protection means for them are not required. In addition, when using existing sounding pipes, installation work can be performed without removing cargo from the cargo hold. As a result, the construction period can be shortened, and the cost saving effect is large.
[Brief description of the drawings]
FIG. 1 is a plan view showing an arrangement of a liquid level detecting device of the present invention.
FIG. 2 is a longitudinal sectional view showing the arrangement of the liquid level detecting device of the present invention.
FIG. 3 is a cross-sectional view in the width direction showing an arrangement of the liquid level detecting device of the present invention.
FIG. 4 is a diagram showing a connection portion between a differential pressure detector and a sounding pipe.
FIG. 5 is a diagram showing a flow of a detection signal.
FIG. 6 is an explanatory diagram of a relationship between an internal pressure and a detection level.
FIG. 7 is a diagram illustrating a change in a detection level.
8 (a) is a wiring diagram of a conventional detector of a cargo ship, and FIG. 8 (b) is a widthwise installation diagram of the arrangement of the detectors.
[Explanation of symbols]
1: bulkhead 2: cargo hold 3: sounding pipe 4: ballast tank 5: differential pressure detector 6: bridge 7: lid 8: pipe 9: converter 10: communication terminal 11: antenna 12: communication terminal 13: antenna 14: Arithmetic unit 15: Level switch

Claims (4)

A differential pressure detector for detecting a differential pressure of the sounding pipe, which is attached to a part on the upper deck of the sounding pipe provided from the upper deck toward the bottom of the ship, and a differential pressure detected by the differential pressure detector. A liquid level detecting device for a ship provided with a sounding pipe, comprising an arithmetic device for calculating a liquid level. 2. The liquid level detecting device for a ship provided with a sounding tube according to claim 1, wherein the arithmetic unit includes a correction means for correcting the detection level fluctuating according to the inclination of the ship by weighted averaging. The liquid level of a ship provided with a sounding tube according to claim 1 or 2, further comprising a communication device that periodically transmits a signal of the detected differential pressure to the differential pressure detector and receives the signal at the arithmetic device. Level detection device. A differential pressure detector attached to a portion of the existing sounding pipe on the upper deck provided from the upper deck toward the bottom of the ship, for detecting a differential pressure of the sounding pipe, and a differential pressure detected by the differential pressure detector. An arithmetic unit that calculates the liquid level from the pressure, compares the calculated liquid level with the set alarm level, and issues an alarm signal when the liquid level reaches the alarm level, and an alarm device that issues an alarm based on the alarm signal An inundation warning device for a ship, comprising:

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