JP4301409B2 - Ballast tank gas detector - Google Patents

Description

  The present invention relates to a gas detection device for detecting a test gas (for example, combustible gas) in a ballast tank of a tanker.

The tanker ballast tank is adjacent to the cargo tank. For this reason, if a crack or damage occurs on the cargo tank wall, cargo such as flammable liquid leaks into the ballast tank. It is dangerous if the flammable liquid vaporizes in the ballast tank and the flammable gas fills the ballast tank.
Therefore, conventionally, a gas detector for detecting combustible gas leaked into the ballast tank has been proposed (see, for example, Patent Document 1).

The gas detection device for a ballast tank is a device that sucks the atmosphere in the ballast tank with a suction pump through a suction path, and detects a test gas in the atmosphere by a gas detection unit provided in the suction path.
Therefore, when there is no ballast water in the ballast tank to be detected, the leakage of cargo (flammable liquid etc.) in the area should be detected.
However, since the ballast tank is filled with seawater depending on the cargo loading situation, there is a possibility that water will be accidentally inhaled when detecting gas leakage in the area for the following reasons (a) to (d). is there.
(A) When, for example, hydrocarbon gas is detected as the test gas in the ballast tank, the specific gravity of the test gas is heavier than air, so it is necessary to install an inlet for the atmosphere in the ballast tank at the bottom of the tank. In such a case, since the piping of the suction path is also laid near the bottom of the tank, water may remain in the suction path piping after draining the ballast tank.
(B) Since the ballast tank is originally a compartment with a lot of moisture, condensed water tends to be generated inside the suction path piping.
Normally, the residual water in the intake passage according to the above (a) and (b) is removed by the air purge operation. However, when the pressure and time of the air purge are not properly performed, the residual water is sucked.
(C) Since the ship repeatedly swings back and forth and left and right, the ballast tank cannot be completely drained, and water often remains in the detection area even when a drain complete signal is received. Therefore, residual water at the bottom of the tank may be sucked by the rocking of the ship.
(D) In addition to the case where the air purge is incomplete, water is also sucked in when a gas detection is performed in a section where water is stretched due to an erroneous operation of the air purge operation.
For the reasons described above, if water is mistakenly sucked when performing gas detection, the water reaches the gas detection unit or the like and causes a failure of the gas detection device.
Conventionally, a system for selecting the suction line of the gas detector in conjunction with the water level signal of the ballast tank has been put into practical use. However, the gas detection device is in a state in which the suction pipe is not sufficiently purged of air by mistake. May cause the device to malfunction.
JP 2003-170893 A

  SUMMARY OF THE INVENTION An object of the present invention is to prevent an apparatus failure caused by sucking water from a suction port in a ballast tank in a suction path.

In order to solve the above problem, a gas detection apparatus of the ballast tanks of the present invention, sucked by the suction pump through the suction path of the ballast tank atmosphere tankers, provided the test gas in the atmosphere in the suction passage A gas detection device for detection by a gas detection unit,
In the suction path, a liquid sensor is provided on the ballast tank side with respect to the gas detection unit, and when the liquid is detected by the liquid sensor, the operation of the suction pump is stopped.
According to such a configuration, when liquid is sucked into the suction path, the liquid is detected by the liquid sensor provided on the ballast tank side of the gas detection unit in the suction path, and the operation of the suction pump is stopped. Will be.
Accordingly, the operation of the suction pump is stopped before the liquid reaches the gas detection unit, and the liquid is prevented from reaching the gas detection unit, thereby preventing the apparatus from being broken.
Also, the gas detector for a ballast tank according to the present invention sucks the atmosphere in the ballast tank of the tanker with a suction pump through the suction path, and detects the test gas in the atmosphere by the gas detection section provided in the suction path. A gas detector that performs
When a liquid sensor and a pressure sensor are provided on the ballast tank side of the gas detection unit in the suction path so that the liquid is detected by the liquid sensor and / or when the liquid is sucked into the suction path When the generated negative pressure is detected by the pressure sensor, the operation of the suction pump is stopped.
According to such a configuration, when liquid is sucked into the suction path, the liquid is detected by the liquid sensor provided on the ballast tank side of the gas detection unit in the suction path, and / or When the negative pressure generated in the suction path due to the suction of the liquid is detected by the pressure sensor provided on the ballast tank side of the gas detection section in the suction path, the operation of the suction pump is stopped.
Therefore, the operation of the suction pump is more reliably stopped before the liquid reaches the gas detection unit, and the liquid can be more reliably prevented from reaching the gas detection unit, thereby preventing an apparatus failure.
The above-described water suction prevention function using a pressure sensor is based on the premise that a relatively large amount of water / liquid enters the suction path and the suction resistance increases and the negative pressure in the suction path becomes excessive.
However, the negative pressure in the suction path does not become so large only by the residual water / condensation water in the suction path piping described in the above-mentioned factors (a), (b) (particularly (b)) causing water suction.
Therefore, if only a pressure sensor is provided in the suction path, water of the above factors (a), (b) (especially (b)) may be gradually sucked, and the suction of the water may be caused by the gas detection device. It may lead to failure.
On the other hand, the above-described water suction prevention function using the liquid sensor stops the operation of the suction pump only when the liquid reaches the liquid sensor portion.
Therefore, even if the liquid is sucked into the suction path, the suction pump continues to operate until the liquid reaches the liquid sensor.
For this reason, if only a liquid sensor is provided in the suction path, the operation of the pump does not necessarily stop promptly during liquid suction, depending on the position of the liquid sensor.
Therefore, depending on the installation position of the liquid sensor, the water sucked into the suction path may reach the gas detection unit.
In contrast, the water suction prevention function using the pressure sensor quickly stops the suction pump when a relatively large amount of water or liquid enters the suction path and the negative pressure in the suction path becomes excessive.
According to the present invention, the liquid sensor and the pressure sensor are provided on the ballast tank side of the gas detection unit in the suction path, and when the liquid is detected by the liquid sensor and / or the liquid is in the suction path. When the pressure sensor detects the negative pressure generated when suctioned, the suction pump stops operating. Therefore, when a relatively large amount of water / liquid enters the suction path and the negative pressure in the suction path becomes excessive. Even if the suction pump is quickly stopped by the operation of the pressure sensor and a relatively small amount of liquid is gradually sucked into the suction path, the suction pump is stopped by the operation of the liquid sensor.
Therefore, before the liquid reaches the gas detector, the suction pump is more reliably stopped, and the liquid can be more reliably prevented from reaching the gas detector, thereby preventing an apparatus failure.
In the present invention, preferably, an air filter is provided closer to the ballast tank than the pressure sensor, and the liquid sensor is provided closer to the ballast tank than the air filter.
If comprised in this way, the air filter provided in the ballast tank side rather than the pressure sensor can also prevent the very small liquid (mist liquid) from reaching the pressure sensor and the gas detection unit.
It is also possible to manually stop the suction pump by visually confirming the adhesion of droplets to the air filter (water trap air filter) in front of the pressure sensor.
In addition, by providing a liquid sensor further on the ballast tank side than the pressure sensor and the air filter, the liquid sensor is disposed closer to the suction port. It is possible to stop early.
In the present invention, it is preferable that the pressure setting value detected by the pressure sensor is a first setting value for detecting a slight negative pressure generated by the operation of the suction pump during normal operation, and a liquid is supplied to the suction path. The second set value for detecting the overnegative pressure generated when sucked is set, and the normal operation of the suction pump is monitored by detecting the slight negative pressure due to the first set value with the pressure sensor. The operation of the suction pump is stopped when an over-negative pressure due to the second set value is detected.
With this configuration, the pressure sensor can be used to monitor not only the operation of the suction pump when the liquid is sucked into the suction path but also the operation of the suction pump during normal operation.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a wiring / piping system diagram showing an embodiment of a gas detection device for a ballast tank according to the present invention, and FIG. 2 is a gas detection monitor panel content diagram.
As shown in these figures (mainly FIG. 1), the gas detection device 1 sucks the atmosphere in the ballast tank T of the tanker with the suction pump 20 through the suction path 10, and detects a test gas (for example, combustible gas) in the atmosphere. A gas detection unit 30 provided in the suction path.
In each section of the tanker ballast tank T (No. 1 WBT in FIG. 1, etc.), a collector 11 constituting a suction port of the suction path 10 is arranged. The collector 11 is connected to a pipe 14 in the gas detection monitor panel 40 (see FIG. 2) via a pipe 12 and a selection valve (close valve) 13 respectively.
The collector 11 is installed at the bottom of each section of the ballast tank T (for example, within 50 cm from the bottom).
The gas detection monitoring panel 40 is usually installed in a cargo handling control room of a tanker.
The selection valve 13 may be a manual valve or an automatic valve (electromagnetic valve). The same applies to each valve described later.

A liquid sensor 50, an air filter 61, a pressure sensor 60, the gas detection unit 30, and the suction pump 20 are provided in the pipe 14 in the gas detection monitoring panel 40 from the ballast tank T side (upstream side of the suction flow). Has been.
As shown in FIG. 2, the gas detector 30 in this embodiment includes a combustible gas detector 30a and a hydrogen sulfide gas detector 30b.
In addition, 70 is a calibration port, 71 is a calibration port valve, 72 is an air purge pipe, 73 is an air purge valve, 74 is an air purge pressure regulator, 75 is a gas detection valve, 76 is a suction pressure adjustment valve, and 77 is the gas detection described above. Bypass piping for bypassing the section 30, 78 is a bypass needle valve, 79 is a flow meter for monitoring the flow rate to the gas detection section 30, and FA is a flame arrester.

3A and 3B are diagrams showing the liquid sensor 50, where FIG. 3A is a front view, and FIG. 3B is a cross-sectional view taken along line bb in FIG.
The liquid sensor 50 includes a transparent cup 51 communicating with the suction path 10 (pipe 14), an optical fiber unit 53 attached to a side surface of the transparent cup 51 with a fastening band 52, and an optical fiber 54 connected to the optical fiber unit 53. The optical fiber amplifier unit 55 is connected to a sequencer 80 (see FIGS. 1 and 2) provided in the gas detection monitoring panel 40.
As shown in FIG. 2B, the light projecting (L1) axis and the light receiving (L2) axis of the optical fiber unit 53 are substantially orthogonal.
Therefore, when there is no liquid in the transparent cup 51, or when no liquid droplet is attached to the inner wall surface of the transparent cup 51, the light projection L1 from the optical fiber unit 53 is reflected by the inner wall surface of the transparent cup 51 and reflected by the optical fiber. Although the light is received (L2) by the unit 53, if there is a liquid in the transparent cup 51 or if a droplet adheres to the inner wall surface of the transparent cup 51, the light projection L1 from the optical fiber unit 53 is the liquid or liquid. It is scattered by the droplets and does not reach the optical fiber unit 53.
Thereby, it is possible to detect that the liquid has been sucked into the suction path 10.
The optical fiber amplifier unit 55 photoelectrically converts light received from the optical fiber unit 53 and amplifies it. When the amount of received light becomes a predetermined value or less (that is, when liquid is detected), the detection signal is sent to the sequencer 80.
When the sequencer 80 receives the liquid detection signal, the sequencer 80 stops the suction pump 20.
Therefore, when the liquid is detected by the liquid sensor 50, the operation of the suction pump 20 is stopped.

4A and 4B are views showing the pressure sensor 60, where FIG. 4A is a front view and FIG. 4B is a side view.
The pressure sensor 60 includes a plurality of operation buttons 63 and a display 64 on the front surface of the main body 62, and a pressure receiving port 65 on the back side. The piping 14 is connected to the pressure receiving port 65 (see FIG. 2), and thereby the pressure in the piping 14 can be detected.
The detected pressure set value can be set by operating the operation button 63.
In this embodiment, as the detected pressure set value, the first set value (for example, −4 kPa) for detecting the slight negative pressure generated by the operation of the suction pump 20 during normal operation, and liquid in the suction path 10 are detected. A second set value (for example, −30 kPa) for detecting an overnegative pressure generated when the suction is performed is set.
The pressure sensor 60 is connected to a sequencer 80 provided in the gas detection monitor panel 40. When the pressure in the pipe 14 reaches (sets) the first set value, the first detection signal is output. When the pressure in the pipe 14 reaches the second set value, the second detection signal is sent to the sequencer 80.
When the sequencer 80 receives the first detection signal, the sequencer 80 includes a first monitor unit 81 (see FIG. 1) in which the gas detection monitoring panel 40 has an indication that the suction pump 20 is operating normally. When the second detection signal is received, the suction pump 20 is stopped.

The operation procedure or operation of the gas detector as described above is as follows.
<Normal time>
The selection valve (stop valve) 13 in the connection portion of the suction pipe 10 with the gas detection monitoring panel 40 is operated to select which section of the ballast tank T is to be measured.
The water level of the ballast tank T is equipped with a monitoring device different from the present device, and the crew member determines which section to measure based on the information.
It should be noted that the measurement section selection can be automatically performed by the sequencer 80 by configuring the selection valve 13 with a solenoid valve as described above. The same applies to each valve described later.
When the measurement section is determined, all the selection valves 13 other than the measurement section are closed, and the suction path 10 of the measurement section is purged with air.
The air purge is performed by operating the pressure regulator 74 and the air purge valve 73 using the compressed air supplied from the ship. The air purge time varies depending on the size of the ship, air purge pressure, etc., but is approximately 5 minutes at 0.3 MPa with φ8 piping 100 m.
After the air purge is completed, the air purge valve 73 is closed and the gas detection valve 75 is opened. The calibration port valve 72 is closed.
The start switch 41 (see FIG. 1) of the gas detection monitor panel 40 is pressed to operate the suction pump 20, and measurement is started. By the operation of the suction pump 20, the atmosphere of the measurement section is sucked from the collector 11 and guided to the gas detection unit 30 through the suction path 10. At this time, the suction pressure adjusting valve 76 is adjusted so that the indicated value of the pressure sensor 60 is −8 to −10 kPa, and the indicated value of the flow meter 79 is about 1 liter / minute by operating the bypass needle valve 78. Adjust so that
And gas concentration is read with the indicator of the combustible instruction | indication unit 31 with which the gas detection part 30 is provided. The time required for the measurement varies depending on the size of the ship, but it requires 1 minute or more with φ8 piping 100m.
When changing the measurement section, press the stop switch 42 (see FIG. 1) of the gas detection monitoring panel 40 to stop the suction pump 20 to interrupt the measurement, open the selection valve 13 for the new measurement section, and select the old section. The valve 13 is closed. After performing the air purge operation for the new section, the start switch 41 is pressed to perform measurement. Thereafter, the above operation is repeated as necessary.

<When inhaling water>
If water is accidentally sucked in the process as described above and the suction path negative pressure exceeds −30 kPa, the second detection signal is sent from the pressure sensor 60 to the sequencer 80 and the suction pump 20 is stopped. At the same time, an alarm is issued from a speaker provided in the gas detection monitoring panel 40.
Further, when water enters the suction path 10 by gradually sucking water or the like, a liquid detection signal is sent from the liquid sensor 50 to the sequencer 80, the suction pump 20 is stopped, and the gas detection monitoring panel 40 is provided. An alarm is issued from the speaker.
In any case, after the stop switch 42 is pressed, the gas detection valve 75 is closed and the air purge valve 73 is opened to perform air purge of the suction path 10.
The water that reaches the liquid sensor 50 is discarded, and the transparent cup 51 is cleaned and restored.

According to the gas detector for a ballast tank of the embodiment as described above, the following operational effects can be obtained.
(1) In this gas detection device for a ballast tank, the atmosphere in the ballast tank T of the tanker is sucked by the suction pump 20 through the suction path 10, and the gas detection unit 30 provided in the suction path 10 with the test gas in the atmosphere. The pressure sensor 50 is provided on the suction path 10 on the ballast tank T side (upstream side) of the gas detection unit 30 in the suction path 10, and a negative generated when liquid is sucked into the suction path 10. When the pressure is detected by the pressure sensor 50, the operation of the suction pump 20 is stopped. Therefore, when the liquid is sucked into the suction path 10, a negative pressure generated in the suction path 10 is caused by this. 10 is detected by the pressure sensor 50 provided on the ballast tank side with respect to the gas detection unit 30, and the operation of the suction pump 20 is stopped.
Therefore, the operation of the suction pump 20 is stopped before the liquid reaches the gas detection unit 30, and the liquid is prevented from reaching the gas detection unit 30, thereby preventing an apparatus failure.

(2) This gas detection device for the ballast tank is provided with a liquid sensor 60 on the suction path 10 on the ballast tank T side of the gas detection unit 30, and when the liquid sensor 60 detects the liquid, Since the operation is stopped, when a liquid is sucked into the suction path 10, the liquid is detected by the liquid sensor 60 provided on the ballast tank side of the gas detection unit 30 in the suction path 10. Thus, the operation of the suction pump 20 is stopped.
Therefore, the operation of the suction pump 20 is stopped before the liquid reaches the gas detection unit 30, and the liquid is prevented from reaching the gas detection unit 30, thereby preventing an apparatus failure.

(3) This gas detection device for a ballast tank is provided with a liquid sensor 50 and a pressure sensor 60 on the suction path 10 closer to the ballast tank than the gas detection unit 30, and when the liquid is detected by the liquid sensor 50, When the negative pressure generated when the liquid is sucked into the suction path 10 is detected by the pressure sensor 60, the operation of the suction pump 20 is stopped, so that the liquid is sucked into the suction path 10. And the negative pressure generated in the suction path 10 when the liquid is detected by the liquid sensor 50 provided on the ballast tank side of the gas detection unit 30 in the suction path 10 and / or by suction of the liquid. Is detected by a pressure sensor 60 provided on the side of the ballast tank with respect to the gas detection unit 30 in the suction path 10. So that the operation of the 20 stops.
Therefore, the suction pump 20 is more reliably stopped before the liquid reaches the gas detection unit 30, and the liquid is prevented from reaching the gas detection unit 30 more reliably, thereby preventing an apparatus failure.

The water suction prevention function using the pressure sensor 60 described above is based on the premise that a relatively large amount of water / liquid enters the suction path 10 and the suction resistance increases to increase the negative pressure in the suction path 10. .
However, the negative pressure in the suction path 10 is not so large with only the residual water / condensation water in the suction path piping described in the above-mentioned factors (a), (b) (particularly (b)) that cause water suction. No.
Therefore, if the pressure sensor 60 is merely provided in the suction path 10, the water of the above factors (a), (b) (particularly (b)) may be gradually sucked, and the suction of the water is detected by the gas detection. It may lead to equipment failure.
On the other hand, in the water suction preventing function using the liquid sensor 50 described above, the operation of the suction pump 20 is stopped only when the liquid reaches the liquid sensor 50.
Therefore, even if the liquid is sucked into the suction path 10, the suction pump 20 continues to operate until the liquid reaches the liquid sensor 50.
For this reason, if a liquid sensor is simply provided in the suction path 10, depending on the installation position of the liquid sensor 50 (for example, when the liquid sensor 50 is provided close to the gas detection unit 30), the liquid sensor 50 is not necessarily at the time of liquid suction. The pump does not stop immediately.
Therefore, depending on the installation position of the liquid sensor, the water sucked into the suction path 10 may reach the gas detection unit 30.
On the other hand, in the water suction prevention function using the pressure sensor 60, when a relatively large amount of water / liquid enters the suction path 10 and the negative pressure in the suction path 10 becomes excessive, the suction pump 20 is quickly stopped.
According to this embodiment, the liquid sensor 50 and the pressure sensor 60 are provided in the suction path 10 on the ballast tank side with respect to the gas detection unit 30, and when the liquid is detected by the liquid sensor 50 and / or the suction. When the negative pressure generated when the liquid is sucked into the passage 10 is detected by the pressure sensor 60, the operation of the suction pump 20 is stopped. Therefore, a relatively large amount of water / liquid enters the suction passage 10 and the negative of the suction passage 10 is detected. When the pressure becomes excessive, the suction pump 20 is quickly stopped by the operation of the pressure sensor 60, and even if a relatively small amount of liquid is gradually sucked into the suction path 10, the suction pump is operated by the operation of the liquid sensor 50. 20 will stop.
Therefore, before the liquid reaches the gas detection unit 30, the suction pump 20 is more reliably stopped, and the liquid reaching the gas detection unit 30 is more reliably prevented, thereby preventing an apparatus failure. The

(4) Since the air filter 61 is provided on the ballast tank side with respect to the pressure sensor 60 and the liquid sensor 50 is provided on the ballast tank side with respect to the air filter 61, the air provided on the ballast tank side with respect to the pressure sensor 60 is provided. The filter 61 can also prevent the extremely small liquid (mist liquid) from reaching the pressure sensor 61 and the gas detection unit 30.
Further, the suction pump 20 can be manually stopped by visually confirming the adhesion of droplets to the air filter (water trap air filter) 61 in front of the pressure sensor 60.
In addition, by providing the liquid sensor 50 further on the ballast tank side than the pressure sensor 60 and the air filter 61, the liquid sensor 50 is disposed closer to the suction port (collector 11), and more quickly. The suction pump 20 can be stopped early by detecting the liquid suction.

(5) As a detected pressure set value by the pressure sensor, a first set value for detecting a slight negative pressure generated by the operation of the suction pump 20 during normal operation, and an excess generated when the liquid is sucked into the suction path 10. The second set value for detecting the negative pressure is set, and the normal operation of the suction pump is monitored by detecting the slight negative pressure by the first set value by the pressure sensor 60, and the over negative pressure by the second set value is detected. Since the operation of the suction pump 20 is stopped when the pressure is detected, the pressure sensor 60 is used to not only stop the suction pump operation when liquid is sucked into the suction path 10 but also the suction pump 20 during normal operation. Operation can also be monitored.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately modified within the scope of the gist of the present invention.

The wiring and piping system figure which shows one Embodiment of the gas detection apparatus of the ballast tank which concerns on this invention. Gas detection monitoring board contents diagram. It is a figure which shows the liquid sensor 50, (a) is a front view, (b) is bb sectional drawing in figure (a). It is a figure which shows the pressure sensor 60, (a) is a front view, (b) is a side view.

Explanation of symbols

T Ballast tank 1 Ballast tank gas detector 10 Suction path 20 Suction pump 30 Gas detector 50 Liquid sensor 60 Pressure sensor 61 Air filter

Claims (4)

A gas detection device that sucks an atmosphere in a ballast tank of a tanker with a suction pump through a suction path, and detects a test gas in the atmosphere by a gas detection unit provided in the suction path,
A gas in the ballast tank, wherein a liquid sensor is provided on the ballast tank side of the gas detection unit in the suction path, and when the liquid is detected by the liquid sensor, the operation of the suction pump is stopped. Detection device. A gas detection device that sucks an atmosphere in a ballast tank of a tanker with a suction pump through a suction path, and detects a test gas in the atmosphere by a gas detection unit provided in the suction path,
When a liquid sensor and a pressure sensor are provided on the ballast tank side of the gas detection unit in the suction path so that the liquid is detected by the liquid sensor and / or when the liquid is sucked into the suction path A gas detection device for a ballast tank, wherein when the generated negative pressure is detected by the pressure sensor, the operation of the suction pump is stopped. 3. The ballast tank according to claim 2 , wherein an air filter is provided on the ballast tank side with respect to the pressure sensor, and the liquid sensor is provided on the ballast tank side with respect to the air filter. Gas detector. As a detected pressure set value by the pressure sensor, a first set value for detecting a slight negative pressure generated by the operation of the suction pump during normal operation, and an overnegative pressure generated when liquid is sucked into the suction path The second set value for detecting the pressure is detected, and the normal operation of the suction pump is monitored by detecting the slight negative pressure by the first set value by the pressure sensor, and the overload by the second set value is detected. 4. The ballast tank gas detection device according to claim 2 , wherein when the pressure is detected, the operation of the suction pump is stopped.

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