Bilge water alarm with optical sensor and flow meter

Abstract

A device for detecting a concentration of a substance in bilge water. The device is arranged for fluid communication with a conduit system (100) of a marine vessel in which bilge water is arranged to flow, the conduit system comprising an outlet arranged such that bilge water may flow out into the sea. The device comprises a casing (270), a pipe segment (230) arranged in the casing (270) for fluid communication with the conduit system (100) of the marine vessel for flow of bilge water therethrough and a radiation arrangement (210) arranged in the casing (270) for measuring the concentration of a substance in bilge water. The radiation arrangement (210) comprises radiation means arranged to emit electromagnetic radiation into the pipe segment (230), and detection means arranged to detect electromagnetic radiation originating from the radiation means. The device further comprises a flow meter arrangement (220) arranged in the casing (270) for measuring a flow of bilge water through the pipe segment (230), wherein the device is arranged to trigger a valve of the conduit system (100) to prevent a flow of bilge water through the outlet when the measured flow is below a predetermined flow value.

Description

BILGE WATER ALARM WITH OPTICAL SENSOR AND FLOW METERTechnical field

[0001] The present invention relates generally to equipment for analyzing bilge water in marine vessels. Particularly the invention relates to apparatuses and methods for detecting a composition of bilge water.Background art

[0002] In marine vessels such as boats and ships, the bilge is the part of the hull that, when the vessel is unsupported by water, would rest on the ground. Bilge also refers to the lowest compartments in the vessel on either side of the keel. Water which enters the ship, for example from rain or heavy sea, may collect in the bilge and is then referred to as bilge water. Bilge water collects different types of debris and dirt when passing through the ship on its way to the bilge such as oil, chemicals, sand, and may therefore not be let back into the sea without first going through a separator for removing unwanted substances.

[0003] Regulatory control of the bilge water which is let back into the sea is increasingly high. Bilge water conduits are therefore often arranged with bilge alarms for detecting a harmful level of an unwanted substance in the bilge water and notifying the crew.

[0004] After passing through the separator, the bilge water is transported in a main conduit which exits into the sea. Commonly, the bilge alarm is positioned after the separator such that it may analyze the bilge water to control that it is sufficiently clean. The bilge alarm may be arranged in direct connection to the main conduit, or the bilge alarm may for example be arranged in connection to a byline conduit, in which a smaller amount of the bilge water may be guided, such that analyzing the water does not interfere with the bilge water flow in the main conduit. The byline is then subsequently lead to reunite with the main conduit. Furthermore, the bilge alarm may be communicatively connected to a valve at an outlet of the main conduit which leads to the sea, such that when an elevated level of an unwanted substance is detected, the bilge alarm triggers the valve to closethe outlet, such that the bilge water cannot flow out into the sea. The bilge water may instead be led back to the separator, or to another part of the conduit system such as to a wastewater tank or back to the bilge.

[0005] A prior art bilge alarm arranged for detecting a harmful level of an unwanted substance in the bilge water is disclosed in EP1893995 B1 , in which unwanted substances are detected with optical means.

[0006] One problem with prior art bilge alarms is that there is a lack of control of the reliability of the analysis of the bilge water. Today, there is no way of knowing if the detected levels of unwanted substances are in fact correct, or if something is causing the bilge alarm to perform faulty measurements.

[0007] For example, there is a lack of control of the time at which the analyzed bilge water entered the bilge alarm, or for how long it has been in the analyzing space of the bilge alarm. For example, the flow of bilge water may be impeded or even stagnant in the analyzing space, such that the same volume of water is being analyzed several times. This may for example occur when the byline conduit is clogged, or if an inlet or outlet of the bilge alarm is clogged, such that flow into or out of the bilge alarm is hindered or stopped. There is therefore a risk that data provided from the alarm does not correspond to the current composition of the bilge water in the main conduit. This may lead to a false positive, wherein the bilge alarm signals that the bilge water is sufficiently clean to let out into the sea, when in reality it is not. It may also lead to a false negative, wherein the bilge alarm signals that the bilge water is not sufficiently clean to let out into the sea and the crew would be required manually analyze the composition of the bilge water, leading to unnecessary, time-consuming work.

[0008] Therefore, there is a need to increase the control of the bilge water passing through the bilge alarm, and an increased control of the reliability of the information provided by the bilge alarm. For example to ensure that the analyzed water corresponds to the water flowing in the main conduit and out into the sea.Summary of invention

[0009] An object of the present invention is to overcome at least some of the problems outlined above.

[0010] In an aspect of the invention there is provided a device for detecting a concentration of a substance in bilge water, the device being arranged for fluid communication with a conduit system of a marine vessel in which bilge water is arranged to flow, the conduit system comprising an outlet arranged such that bilge water may flow out into the sea. The device comprises a casing, a pipe segment arranged in the casing arranged for fluid communication with the conduit system of the marine vessel for flow of bilge water therethrough, a radiation arrangement arranged in the casing for measuring the concentration of a substance in bilge water. The radiation arrangement comprises radiation means arranged to emit electromagnetic radiation into the pipe segment, and detection means arranged to detect electromagnetic radiation originating from the radiation means. The device further comprises a flow meter arrangement arranged in the casing for measuring a flow of bilge water through the pipe segment, wherein the device is arranged to trigger / cause a valve of the conduit system to prevent a flow of bilge water through the outlet when the measured flow is below a predetermined flow value.

[0011] The disclosure is based on the insight that, when it is detected that the flow of bilge water through the device is lower than desired, there is a risk that measurements of the water, such as measurements of unwanted substances, are not representative and / or not accurate. Specifically, water may potentially be completely unmoving in the device. In such a case, a user may not know for how long the water in the device has been unmoving. This may produce both false positive output data and false negative output data. Therefore, the disclosure provides that water from the bilge is not let out into the sea unless it is certain that quality of the water is satisfactory, and that the measurements of the quality of the water are representative and / or accurate.

[0012] By arranging the pipe segment, radiation arrangement and flow meter arrangement in the casing, manipulation of the device and tampering with theelectronic equipment therein is prevented. To compare, if a flow meter would be arranged such that it is easily accessed, and it would be possible to tamper with the flow meter arrangement, for example, make it appear as the bilge water is cleaner than it really is and avoid regulatory demands.

[0013] In one embodiment, the radiation arrangement is arranged to measure the concentration at a first part of the pipe segment, and wherein the flow meter arrangement is arranged to measure the flow at a second part of the pipe segment, wherein the first part is arranged upstream of the second part, in a flow direction of the bilge water through the pipe segment.

[0014] In one embodiment, an inner diameter of the first part of the pipe segment is greater than an inner diameter of the second part.

[0015] The smaller the diameter where the flow is measured, the higher is the velocity of the flow at that position. The velocity is directly proportional to the potential difference being measured by the flow meter arrangement. Thus, a decreased diameter increases accuracy of the measurement by the flow meter. However, a relatively small diameter may not be as desirable where the concentration is measured since the flow volume needs to be sufficiently large to give an accurate measurement. Thus, it may be advantageous to have different diameters.

[0016] In one embodiment, the flow meter arrangement is a magnetic flow meter arrangement, comprising a magnet arranged to induce a magnetic field perpendicular to an extension of the pipe segment, and sensor means arranged to measure a voltage induced by the magnetic field, and to transfer a signal comprising voltage data of the measured voltage.

[0017] In one embodiment, the sensor means comprises two electrodes arranged on opposite sides of a diameter of the pipe segment, such that a voltage may be measured perpendicular to the induced magnetic field.

[0018] In one embodiment, the radiation arrangement is one of a Raman spectroscopy detector, an optical detector, or a fluorescent light detector.

[0019] One advantage of the present disclosure is that it is compatible with a variety of radiation arrangements for measuring the composition of bilge water.

[0020] In one embodiment, the device comprises a computing unit, arranged in the casing and to receive measurement data from the radiation arrangement and the flow meter arrangement, to process said received data, and to communicate with an external unit.

[0021] As such, the device may have a common communication to an external unit from the computing unit instead of for example communicating from the radiation arrangement and the flow meter arrangement separately. Furthermore, processing of the data, such as comparing measured values with threshold values, can be performed in the device instead of external to the device.

[0022] In one embodiment, the computing unit is arranged to process the received data to provide a single output signal being based on both the measurement data from the radiation arrangement and the flow meter arrangement, and communicate said output signal to an external unit.

[0023] This is advantageous because the external unit would require less processing power and consume less energy, since the information it is receiving is already processed. Furthermore, an advantage is that the device is compatible with units which may only be adapted to receive one kind of measurement values.

[0024] In one embodiment, the device comprises means for detecting whether the casing has been opened.

[0025] By providing means for detecting whether the casing has been opened, it is possible to detect unauthorized access to the components in the device, which is a sign that the components have been tampered with.

[0026] In one embodiment, the means for detecting whether the casing has been opened comprises a seal attached to the casing such that the casing cannot be opened without breaking the seal.

[0027] In a second aspect of the disclosure, there is provided an arrangement comprising a control unit and a device according to the disclosure being releasably attached to the control unit. The control unit is arranged to cause a valve of the conduit system to prevent a flow of bilge water through the outlet when at least one of the following criteria is fulfilled: a measured concentration received from the device is above a predetermined concentration value, and a measured flow received from the device is below a predetermined flow value.

[0028] Having the device releasably attached to the control unit provides that the device may be easily removed for example for maintenance or to be exchanged. It is thereby possible to have the control unit more securely attached to a structure of the marine vessel, and it is therefore not necessary to remove the control unit together with the device.

[0029] In one embodiment, the control unit comprises electrical circuitry for communicating with the conduit system for controlling valves of the conduit system.

[0030] In one embodiment, the control unit comprises at least one of a display, a loudspeaker, a light or a digital communication means for communication with a user of the apparatus.

[0031] Communicating with the user provides both that an alarm may be sent when the flow and or / concentration is at an undesired level. Furthermore, a user may change the settings of the apparatus, deepening for example on what substances are to be measured or changing threshold values or what valves are to be affected by the measurements.

[0032] In one embodiment, the arrangement comprises a computing unit, arranged in the casing of the device and to receive measurement data from the radiation arrangement and the flow meter arrangement, the computing unit being arranged to communicate with the control unit.

[0033] In a third aspect of the invention, there is provided a method for detecting a concentration of a substance in bilge water. The method is performed by anarrangement in fluid communication with a conduit system of a marine vessel in which bilge water flows. The conduit system comprises an outlet arranged such that bilge water may flow out into the sea. The arrangement comprises a control unit, a casing releasably attached to the control unit, a pipe segment arranged in the casing in fluid communication with the conduit system of the marine vessel for flow of bilge water therethrough, a radiation arrangement arranged in the casing comprising radiation means emitting electromagnetic radiation into the pipe segment, and detection means detecting electromagnetic radiation originating from the radiation means, and a flow meter arrangement arranged in the casing. The method comprises measuring, by the radiation arrangement, a concentration of a substance in the bilge water, measuring by the flow meter arrangement a flow of the bilge water, causing, by the control unit, a valve of the conduit system to prevent a flow of bilge water through the outlet when at least one of the following criteria is fulfilled: the measured concentration is above a predetermined concentration value and the measured flow is below a predetermined flow value.

[0034] In one embodiment, the method comprises communicating to a user that the measured flow is below the predetermined flow value and / or measured concentration is above the predetermined concentration value.

[0035] In one embodiment, the flow meter arrangement is a magnetic flow meter arrangement, and the measuring of the flow comprises measuring a difference in electric potential, wherein the difference in electric potential is induced by a flow of bilge water through a magnetic field generated by the magnetic flow meter arrangement.

[0036] In one embodiment, the method comprises alternating the direction of the magnetic field generated by the flow meter arrangement at a first frequency.

[0037] In one embodiment, the measuring of the concentration comprises pulsing electromagnetic radiation into the pipe segment at a second frequency, and wherein the first frequency and the second frequency are in phase.

[0038] Both the magnetic field and the electromagnetic radiation are relatively weak which may cause interference therebetween. If the frequency of the two are set to be in phase, or equal, interference and / or the source of the interference may be determined with higher accuracy.

[0039] In one embodiment, the arrangement further comprises a computing unit, arranged in the casing and to receive measurement data from the radiation arrangement and the flow meter arrangement, the computing unit being arranged to communicate with the control unit, the method comprising: receiving, by the computing unit, a measured concentration value, receiving, by the computing unit, a measured flow value, processing the measured concentration value and the measured flow value, communicating a concentration value to the control unit, the communicated concentration value being determined based on at least the measured flow value.

[0040] In one embodiment, processing the measured concentration value and the measured flow value comprises: comparing the measured flow value to the predetermined flow value, when the measured flow is below the predetermined flow value, setting a concentration parameter to a value above the predetermined concentration value or to a maximum value, communicating the concentration value to the control unit by means of the computing unit.

[0041] Brief description of drawings

[0042] The invention is now described, by way of example, with reference to the accompanying drawings, in which:Fig. 1 displays a conduit system and an arrangement for detecting substance in water.Fig. 2 displays an arrangement for detecting substance in water.Fig. 3 displays a radiation arrangement.Fig. 4 displays a flow meter arrangement.Fig. 5 displays a method for detecting substance in water.Fig. 6 displays a method for detecting substance in water.Description of embodiments

[0043] In the following, a detailed description of an arrangement, a device and a method for detecting a substance in water is disclosed. Specifically, there is provided an arrangement, a device and a method for detecting an unwanted substance in bilge water in a marine vessel and for measuring a flow of bilge water through the arrangement / device. In the figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and do not in any way restrict the scope of the present disclosure.

[0044] With reference to Fig. 1 , there is displayed a conduit system 100 of a marine vessel. Preferably the conduit system 100 is a system for transport of bilge water. The conduit system 100 generally comprises a separator 110, a main conduit 120 and a control conduit 130. The separator 110 is arranged for cleaning bilge water from undesired substances such as oil, soot, debris, lubricants, sand. Bilge water deriving from the bilge enters the separator 110. Cleaned water exits the separator 110 out into the main conduit 120. The main conduit 120 transports bilge water from the separator 110 out into the sea. The control conduit 130 has an inlet 131 in fluid communication with the main conduit 120. The control conduit 130 furthermore has an outlet 132 which may be in fluid communication with the main conduit 120 downstream of the inlet 131 , such that a flow of water may be diverted from the main conduit 120 through the control conduit 130 and subsequently back to the main conduit 120. The outlet 132 of the control conduit 130 may alternatively be connected to a storage tank for wastewater. The outlet132 of the control conduit 130 may alternatively be reconnected to the bilge. As such, the water exiting the control conduit 130 may at a later point again be guided to the separator 110. The control conduit 130 may have a diameter smaller than that of the main conduit 120, such that the diverted water has a smaller volume than the water in the main conduit 120. Alternatively, the control conduit 130 may have a diameter essentially equal to that of the main conduit 120.

[0045] The purpose of the control conduit 130 is to divert water from the main conduit 120 for assessment of the quality of the water such that it is sufficiently clean to be let out into the sea. As such, the quality of the water may be assessed without the risk of interrupting the flow of water in the main conduit 120. The quality may be defined as the composition of the water. The quality may be defined as the oil concentration in the bilge water.

[0046] In an alternative embodiment, the conduit system does not comprise the control conduit, but the assessment of the quality of the bilge water is performed directly in the main conduit. Determining whether to provide a control conduit or not may be based on the size of the main conduit, such as the diameter. It can generally be said that the assessment may be performed directly on the water flowing through the main conduit for main conduits of smaller diameters, whereas a control conduit may be required for larger diameter main conduits.

[0047] The conduit system 100 furthermore comprises a main valve 140 at an outlet of the main conduit 120, downstream of where the main conduit 120 is connected to the inlet 131 of the control conduit 130. The main valve 140 is connected to a main system for controlling the main valve 140. The main system may control the main valve to open and close the outlet of the main conduit 120. The main system may furthermore control additional valves of the conduit system 100 in order to guide the bilge water into a desired conduit.

[0048] When the outlet of the main conduit 120 is closed, water from the main conduit 120 is not allowed to flow to the sea. A closed outlet may stop the flow of bilge water in the main conduit 120 or cause the bilge water to be guided into another conduit, for example leading to a storage space or back to the bilge or anadditional separator or leading back to the first separator 110 for additional cleaning. When the outlet of the main conduit 120 is open, the bilge water is allowed to flow to the sea.

[0049] In order to assess the quality of the bilge water, an arrangement 200 for detecting a concentration of a substance in water is arranged in fluid communication with the main conduit 120, for example via the control conduit 130. The arrangement 200 generally comprises a control unit 240 in communicative connection with the main system controlling the main valve 140, and a device for performing measurements. The control unit 240 comprises a user interface 241 such as a display, an audio alarm, a light or means for digital communication. The arrangement 200 is connected to the control conduit 130 by an inlet connection 250 and an outlet connection 260. The inlet connection 250 and outlet connection 260 may for example be a compression fitting, such as a threaded compression fitting. The inlet connection 250 and outlet connection 260 may comprise valves. The inlet connection 250 and outlet connection 260 are preferably arranged on the device.

[0050] The device comprises a radiation arrangement 210 and a flow meter arrangement 220, arranged in a casing 270. The device, and thus the radiation arrangement 210 and the flow meter arrangement 220 can be seen in Fig. 2. The control unit is arranged external to the casing.

[0051] The arrangement 200 comprises securing means 280 for securing the arrangement 200 to an existing structure of the marine vessel for simple connecting and disconnecting, for example during maintenance or installation.

[0052] With reference to Fig. 2, there is displayed the device of the arrangement 200 for detecting a concentration of a substance in water. The device generally comprises the radiation arrangement 210, the flow meter arrangement 220, and a pipe segment 230. The control unit 240 (seen in Fig. 1 ) is arranged to receive information from the radiation arrangement 210 and the flow meter arrangement 220. A cross-sectional plane A-A is represented by a dashed line in Fig. 2. The cross-sectional plane A-A represents a cross-section of the pipe segment 230, andis perpendicular to the extension of the pipe segment 230, and thus also perpendicular to the direction of the flow of bilge water, when it flows therethrough. The plane A-A can furthermore be seen in Fig. 4.

[0053] The device may furthermore comprise a computing unit (not displayed) arranged to process measurements from the radiation arrangement 210 and the flow meter arrangement 220. To this end, the computing unit is preferably arranged in the casing 270. The computing unit may be arranged to communicate measurement data to the control unit 240. The computing unit may communicate concentration measurement data and / or flow measurement data. The computing unit may receive measurement data from the flow meter arrangement 220 and determine if the flow of bilge water is below a predetermined flow value. The computing unit may be arranged to process concentration measurement data and flow measurement data and communicate information to the control unit being based on the processed data.

[0054] The inlet connection 250 and the outlet connection 260 connects the arrangement 200 in fluid communication with the control conduit 130 of the conduit system 100 seen in Fig. 1 . The pipe segment 230 is connected at one end to the inlet connection 250, and at another end to the outlet connection 260, such that bilge water from the control conduit 130 may flow therethrough. The inlet connection 250 and the outlet connection 260 furthermore provide that the arrangement 200 may be easily connected and disconnected from the conduit system 100. Specifically, the device may be connected and disconnected for example during maintenance of the device, or when installing or replacing the device.

[0055] The radiation arrangement 210, the flow meter arrangement 220 and the pipe segment 230 are provided in the casing 270. The casing is essentially completely sealed, meaning that an operator does not have access to the inside of the casing 270. The casing is furthermore preferably sealed from water and light. In one embodiment, the casing may be openable for example via a lid or cover. However, the lid or cover is not intended to be opened during use. In an alternativeembodiment, the casing 270 is permanently sealed. The radiation arrangement 210 and the flow meter arrangement 220 may be in communicative connection with the control unit 240 for example by means of magnetic communication or by optical communication. In the latter case, the casing 270 may comprise a small opening for radiation to pass therethrough. The casing 270 furthermore comprises fastening means 271 for fastening the casing 270, and thus the device, to the control unit 240. The fastening means 271 preferably provides releasable fastening of the casing 270 to the control unit 240, such that the device may be removed from the arrangement 200 to be separately replaced. This may for example be necessary if the radiation arrangement 210 and / or the flow meter arrangement 220 needs replacing.

[0056] The casing 270 prevents manipulation of the device, and thus the arrangement 200.

[0057] In one embodiment, the casing comprises a means for detecting manipulation of the device. In one embodiment, the means is for detecting if the casing 270 has been opened.

[0058] In one embodiment, the means for detecting if the casing 270 has been opened comprises a seal, for example in the form of a label or sticker. The seal is attached to the casing such that the casing 270 cannot be opened without breaking the seal. For example, the casing 270 may comprise an openable lid or cover, and the seal may be placed over a joint of the lid or cover, such that the lid or cover cannot be opened without breaking the seal.

[0059] In one embodiment, the means for detecting if the casing 270 has been opened comprises an electronic means. The electronic means may for example be a photocell or an electronic switch. For example, the casing 270 may comprise an openable lid or cover, and the electronic means is arranged to transmit a signal when detecting that the lid or cover has been opened. The signal may for example be transmitted to the computing unit or control unit.

[0060] In one embodiment, the means for detecting manipulation comprises an interference detector for detecting if the casing is exposed to an interference radiation or interference signal, such as a wireless electrical signal attempting to tamper with the flow meter arrangement or radiation arrangement. The interference detector may be arranged to transmit a signal when detecting interference. The signal may for example be transmitted to the computing unit or control unit.

[0061] In one embodiment, the casing 270 is made of metal. The metal contributes to shielding of components arranged in the casing. This prevents intentional or accidental manipulation of the electronic components the device, such as by an interference radiation or interference signal. Specifically, manipulation of the radiation arrangement 210 and / or a flow meter arrangement 220 and / or computing unit can be prevented. In one embodiment the casing is made from aluminum or an alloy thereof.

[0062] In one embodiment, the casing 270 comprises a shielding layer on at least one surface thereof. The shielding layer may be attached to or formed together with the casing 270. The shielding layer prevents intentional or accidental manipulation of the electronic components of the device.

[0063] The radiation arrangement 210 is arranged to measure a concentration of a substance in the bilge water flowing through the pipe segment 230. To this end, the radiation arrangement 210 is arranged in connection to a first part 231 of the pipe segment 230. The radiation arrangement 210 generally comprises radiation means arranged to emit electromagnetic radiation and detection means arranged to detect radiation. The radiation arrangement 210 may be an optical measuring arrangement, a Raman measuring arrangement, a fluorescence measuring arrangement or another suitable measuring arrangement. An embodiment of the radiation arrangement 210 in the form of an optical measuring arrangement 211 can be seen in Fig. 3.

[0064] The optical measuring arrangement 211 seen in Fig. 3 comprises at least one radiation emitter 212 arranged to emit electromagnetic radiation into andthrough the pipe segment 230. To this end, the first part 231 of the pipe segment 230 is formed by a transparent material such as glass, plastic or quartz. The first part 231 of the pipe segment 230 may be a cuvette. The at least one radiation emitter 212 may be arranged such that radiation is emitted in a direction essentially perpendicular to the extension of the pipe segment 230. The radiation emitter 212 may emit continuous radiation or pulsing at regular or irregular intervals. Furthermore, a frequency of the intervals may be controlled, preferably by the control unit 240.

[0065] The optical measuring arrangement 211 comprises at least one radiation detector 213 arranged to detect radiation emitted from the at least one radiation emitter 212.

[0066] During use, when bilge water flows through the pipe segment 230, radiation from the at least one radiation emitter 212 passes through the flow of bilge water. Properties of the radiation which reaches the at least one radiation detector 213 after passing through the water is dependent on the composition of the bilge water. In one embodiment, the radiation is reflected in different angles depending on the composition, the radiation detector 213 thus detects the amount of radiation which reaches the radiation detector 213. In one embodiment, the radiation reacts with the water, such that a wavelength of the radiation is altered depending on the composition, the radiation detector 213 thus detects a wavelength of the radiation which reaches the radiation detector 213.

[0067] A plurality of emitter-detector pairs may be provided, such that concentrations of a plurality of substances may be detected by the optical measuring arrangement 211 . Additional optical components may be provided such as optical filters or prisms.

[0068] The flow meter arrangement 220 according to the disclosure is seen in Fig. 4. The flow meter arrangement 220 is arranged to measure the flow of bilge water thorough the pipe segment 230. To this end, the flow meter arrangement 220 is arranged in connection to a second part 232 of the pipe segment 230.

[0069] In the embodiment displayed in Fig. 4, the flow meter arrangement 220 is a magnetic flow meter. Generally, a magnetic flow meter measures the flow of a liquid through a pipe by measuring an induced potential difference in the liquid when it passes through a magnetic field B generated by the magnetic flow meter. The flow meter arrangement 220 may be an electromagnetic flow meter.

[0070] The flow meter arrangement 220 comprises a magnet 221 . The magnet 221 may be an electromagnet. In the embodiment in Fig. 4 the magnet 221 is provided in the form of a magnetic core extending along at least part of the circumference of the pipe segment 230. A coil 222 is provided surrounding a part of the core. The coil 222 is preferably a copper coil in which an electric current may be induced. To this end, the flow meter further comprises electric circuitry for inducing an electric current through the coil 222. When an electric current is induced in the coil 222, a magnetic field B is generated between a first and second end of the core, which then become a first and second magnetic pole, respectively. The second part 232 of the pipe segment 230 is arranged between the first and second end of the core, such that the generated magnetic field B passes through the pipe segment 230 in a direction of a diameter thereof, and thus a direction perpendicular to an extension of the pipe segment and the flow of bilge water therethrough. In one embodiment, the current through the coil 222 is arranged to alternate at a given frequency, such that the direction of the magnetic field B alternates at the same given frequency.

[0071] In an alternative embodiment, a first and second magnet is provided. The second part 232 of the pipe segment 230 may then be arranged between a pole of the first magnet and a pole of the second magnet, such that a magnetic field generated between the two poles passes through the second part 232 of the pipe segment 230 in a direction of a diameter thereof, and thus a direction perpendicular to the flow of bilge water. Each of the first and second magnet is provided with a coil such that, when an electric current is induced in the respective coil, the magnetic field B is generated. In order to for a magnetic field B to be generated, the directions of the respective currents are such that the pole of the first magnet which is directed towards the second part 232 of the pipe segment230 is of opposite polarity compared to the pole of the second magnet which is directed towards the second part 232 of the pipe segment 230. In one embodiment, the current through each coil is alternating at a given frequency, such that the direction of the magnetic field B alternates at the same given frequency.

[0072] In an alternative embodiment, the magnet is a permanent magnet. When a permanent magnet is provided, no coil and associated electrical circuitry is needed to generate the magnetic field B.

[0073] The magnetic flow meter furthermore comprises sensor means 223. The sensor means 223 comprises two electrodes arranged to measure a difference in electric potential between them, wherein the difference in electric potential is induced by a flow of bilge water through the second part 232 of the pipe segment 230. The electrodes are arranged opposite each other, on the outer circumference of the second part 232 of the pipe segment 230. The electrodes are arranged to measure the potential difference E where the magnetic field B is generated. Preferably, the potential difference E is measured between the electrodes, along the dashed line B-B in Fig. 4. The line B-B is preferably essentially parallel to a diameter if the pipe segment 230 and thus perpendicular to the extension of the pipe segment 230. The line B-B preferably lies in the plane A-A.

[0074] In one embodiment, the radiation arrangement 210 is arranged to measure the concentration at the first part 231 of the pipe segment 230, and the flow meter arrangement 220 is arranged to measure the flow at the second part 232 of the pipe segment 230, wherein the first part 231 is upstream of the second part 232 in a flow direction of the bilge water through the pipe segment 230.

[0075] In one embodiment a diameter of the first part 231 is larger than a diameter of the second part 232. In a flow of a liquid such as water, the induced potential difference E may be low and difficult to measure. Decreasing the diameter provides that a flow rate V of the liquid increases, the flow rate V is in turn directly proportional to the induced potential difference E. Thus, the potential difference E increases and is therefore easier to measure. It is advantageous thatthe second part 232, having the smaller diameter, is arranged downstream of the first part 231 . This is to avoid formation of gas bubbles in the flowing bilge water when the diameter, and thereby the pressure, changes.

[0076] The control unit 240 (seen in Fig 1 ) generally comprises processing circuitry, a memory and means for communicating with the device, such as with the radiation arrangement, the flow meter arrangement and / or the computing unit. The communication means is arranged to receive measurement data relating to the bilge water quality from the radiation arrangement 210, optionally via the computing unit. Such measurement data may be for example the concentration of oil or other substances in the bilge water. The measurement data may be data relating to detected radiation from the radiation detector 213. In one embodiment, the communication means is furthermore arranged to receive measurement data relating to the flow of the bilge water through the pipe segment 230, received from the flow meter arrangement 220, optionally via the computing unit. Such measurement data may be for example voltage data. The memory contains instructions executable by the processing circuitry. The control unit may determine, based on at least one received measurement, that a quality of the bilge water is insufficient or that a flow of bilge water through the arrangement 200 is insufficient. The control unit may have stored, predetermined values with which measurement data is compared to determine that a quality of the bilge water is insufficient or that a flow of bilge water through the arrangement 200 is insufficient. The control unit furthermore comprises the user interface 241 , seen in Fig. 1. By means of the user interface 241 , a user may receive an alarm or notification from the arrangement 200, for example when a quality of the bilge water is insufficient or when a flow of bilge water through the arrangement 200 is insufficient.

[0077] In one aspect of the present disclosure, there is provided a method for detecting a concentration of a substance in bilge water, seen in Fig. 5. The method may be performed by the arrangement 200 according to the present disclosure.

[0078] A first, general embodiment of the method comprises performing at least one measurement of a concentration of a substance in bilge water by means ofthe radiation arrangement and performing at least one measurement of the flow of bilge water by means of the flow meter arrangement, wherein the measurements may be performed together and / or independently of each other. Measurement data is communicated to the control unit, wherein the data may be communicated together and / or independently of each other. The control unit determines if the measured concentration is above a predetermined concentration value, and / or if the measured flow is below a predetermined flow value. If at least one of the criteria is determined to be true, the control unit is triggered to cause a valve of the conduit system to prevent bilge water to flow into the sea, for example by closing the main valve of the conduit system.

[0079] In one embodiment of the method, the control unit bases the determination only on concentration data, wherein the concentration data comprises information both relating to concentration and indirectly to the flow. To achieve this, the device may comprise the computing unit which may receive both measurement data relating to the concentration and measurement data relating to the flow. In this embodiment, the computing unit determines if the measured flow is below the predetermined flow value, and in that case sets a parameter representing the measured concentration to a maximum value, and subsequently communicates the concentration value to the control unit. The control unit compares the received concentration value to a predetermined concentration value and inevitably determines that the concentration value is above the predetermined concentration value. The control unit thus prevents bilge water to flow into the sea. One advantage of this embodiment is that the control unit would only need to be capable of receiving / processing information relating to the measured concentration. This is advantageous because the control unit would require less processing power and consume less energy. Furthermore, an advantage is that the device according to the invention would be compatible with older / other models of control units, which may not be adapted to receive measurement data relating to the flow, but only to the concentration. The embodiment of the method may be described in the following steps:

[0080] S1 a: Performing at least one measurement of a concentration of a substance in bilge water by means of the radiation arrangement.

[0081] S2a: Communicating concentration data of the concentration measurement to the control unit by means of the radiation arrangement or the computing unit.

[0082] S3a: Performing at least one measurement of the flow of bilge water by means of the flow meter arrangement.

[0083] S4a: Comparing the flow data to a predetermined flow value by means of the computing unit.

[0084] S5a: When a flow is below the predetermined flow value, setting a concentration parameter to a maximum value.

[0085] S6a: Communicating the concentration parameter to the control unit by means of the computing unit.

[0086] S7a: Comparing the concentration data and / or parameter to a predetermined concentration value by means of the control unit.

[0087] S8a: Causing the main valve to prevent a flow of bilge water through the outlet of the main conduit when the concentration data / concentration parameter exceeds a predetermined concentration value.

[0088] The steps S1a-S2a, and S3a-S6a respectively, may be performed simultaneously and / or subsequently and / or independently of each other.

[0089] The steps S7a-S8a are triggered when the control unit receives concentration data / concentration parameter from the device.

[0090] In an alternative embodiment of the method, both the flow measurement data and the concentration measurement data are communicated to the control unit, wherein the control unit determines if either the measured concentration is above a predetermined concentration value, or the measured flow is below apredetermined flow value. If at least one of them is true, the control unit causes the main valve to prevent a flow of bilge water through the outlet of the main conduit. The embodiment of the method may be described in the following steps:

[0091] S1 b: Performing at least one measurement of a concentration of a substance in bilge water by means of the radiation arrangement.

[0092] S2b: Communicating concentration data of the measurement to the control unit by means of the radiation arrangement or the computing unit.

[0093] S3b: Comparing the concentration data to a predetermined concentration value.

[0094] S4b: Causing the main valve to prevent a flow of bilge water through the outlet of the main conduit when the concentration data exceeds the predetermined concentration value.

[0095] S5b: Performing at least one measurement of the flow of bilge water by means of the flow meter arrangement.

[0096] S6b: Communicating flow data of the flow measurement to the control unit by means of the flow meter arrangement or the computing unit.

[0097] S7b: Comparing the flow data to a predetermined flow value.

[0098] S8b: Causing the main valve to prevent a flow of bilge water through the outlet of the main conduit if the flow data is below the predetermined flow value.

[0099] The steps S1 b-S4b, and S5b-S8b respectively, may be performed simultaneously and / or subsequently, and / or independently of each other.

[0100] The method according to the disclosure may furthermore comprise communicating that a decreased flow of bilge water has been detected if the flow data is below the predetermined flow value and / or communicating that an increased concentration of a substance has been detected if the concentration data exceeds the predetermined concentration value. Communicating maycomprise communicating with a user of the arrangement through a user interface, wherein the interface may comprise a visual means such as a display or a light, an audible means or a digital means for further processing, or another communication means known to the skilled person.

[0101] The method may be repeated a plurality of times.

[0102] Performing at least one measurement of a concentration of a substance may be by means of optical measuring, Raman spectroscopy measuring, florescence measuring, or another measuring method know to the skilled person. The substance may be oil or another fatty substance. The substance may be sand or other solid particles. The concentration data may be data relating to detected radiation by the radiation arrangement. As such, the predetermined concentration value may be a radiation threshold value.

[0103] Performing at least one measurement of the flow may comprise measuring the potential difference. The flow data may be a potential difference measured by the flow meter arrangement. As such, the predetermined flow value may be a potential difference threshold value.

[0104] Performing a measurement of the flow may comprise alternating the direction of magnetic field at a first frequency. The step of performing a measurement of the concentration may comprise pulsing radiation into the pipe segment at a second frequency. In one embodiment the first frequency is equal to the second frequency. In one embodiment the first frequency and the second frequency are in phase.

[0105] An arrangement, a device and a method for detecting a concentration of a substance in bilge water has now been described. All examples herein should be seen as part of the general description and are therefore possible to combine in any way in general terms. Individual features of the various embodiments may be combined or exchanged unless such combination or exchange is clearly contradictory to the overall function. Modifications and variations may be apparent to the person skilled in the art.

Claims

CLAIMS1 . A device for detecting a concentration of a substance in bilge water, the device being arranged for fluid communication with a conduit system (100) of a marine vessel in which bilge water is arranged to flow, the conduit system comprising an outlet arranged such that bilge water may flow out into the sea, the device comprising: a casing (270), a pipe segment (230) arranged in the casing (270), arranged for fluid communication with the conduit system (100) of the marine vessel for flow of bilge water therethrough, a radiation arrangement (210) arranged in the casing (270), for measuring the concentration of a substance in bilge water, the radiation arrangement (210) comprising: radiation means arranged to emit electromagnetic radiation into the pipe segment (230), and detection means arranged to detect electromagnetic radiation originating from the radiation means, and a flow meter arrangement (220) arranged in the casing (270), for measuring a flow of bilge water through the pipe segment (230), wherein the device is arranged to trigger a valve of the conduit system (100) to prevent a flow of bilge water through the outlet when the measured flow is below a predetermined flow value.

2. The device according to claim 1 , wherein the radiation arrangement (210) is arranged to measure the concentration at a first part (231 ) of the pipe segment (230), and wherein the flow meter arrangement (220) is arranged to measure the flow at a second part (232) of the pipe segment (230), wherein the first part (231) is arranged upstream of the second part (232), in a flow direction of the bilge water through the pipe segment (230).

3. The device according to claim 2, wherein an inner diameter of the first part (231 ) of the pipe segment (230) is greater than an inner diameter of the second part (232).

4. The device according to any one of the preceding claims, wherein the flow meter arrangement (220) is a magnetic flow meter arrangement (220), comprising: a magnet (221 ) arranged to induce a magnetic field perpendicular to an extension of the pipe segment (230), sensor means (223) arranged to measure a voltage induced by the magnetic field, and to transfer a signal comprising voltage data of the measured voltage.

5. The device according to any one of the preceding claims, wherein the radiation arrangement (210) is one of a Raman spectroscopy detector, an optical detector, or a fluorescent light detector.

6. The device according to any one of the preceding claims, further comprising a computing unit, arranged in the casing and to receive measurement data from the radiation arrangement (210) and the flow meter arrangement (220), to process said received data, and to communicate with an external unit.

7. The device according to claim 6, wherein the computing unit is arranged to process the received data to provide a single output signal being based on both the measurement data from the radiation arrangement and the flow meter arrangement, and communicate said output signal to an external unit.

8. The device according to any one of the preceding claims, further comprising means for detecting whether the casing (270) has been opened.

9. The device according to claim 8, the means for detecting whether the casing (270) has been opened comprising a seal attached to the casing such that the casing (270) cannot be opened without breaking the seal.

10. An arrangement (200) comprising: a control unit (240), and a device according to any one of the preceding claims , being releasably attached to the control unit (240), wherein the control unit (240) is arranged to cause a valve of the conduit system to prevent a flow of bilge water through the outlet when at least one of the following criteria is fulfilled: a measured concentration received from the device is above a predetermined concentration value, and a measured flow received from the device is below a predetermined flow value.

11. The arrangement (200) according to claim 10, wherein the control unit (240) comprises electrical circuitry for communicating with the conduit system (100) for controlling valves of the conduit system (100).

12. The arrangement (200) according to any one of the preceding claims 10- 11 , wherein the control unit (240) comprises at least one of a display, a loudspeaker, a light or a digital communication means for communication with a user of the arrangement (200).

13. The arrangement (200) according to any one of the preceding claims 10- 12 further comprising a computing unit, arranged in the casing of the device and to receive measurement data from the radiation arrangement (210) and the flow meter arrangement (220), the computing unit being arranged to communicate with the control unit (240).

14. A method for detecting a concentration of a substance in bilge water, wherein the method is performed by an arrangement (200) arranged in fluid communication with a conduit system (100) of a marine vessel in which bilge water flows, the conduit system comprising an outlet arranged such that bilge water may flow out into the sea, the arrangement (200) comprising: a control unit (240), a casing (270) releasably attached to the control unit (240),a pipe segment (230) arranged in the casing (270), in fluid communication with the conduit system (100) of the marine vessel for flow of bilge water therethrough, a radiation arrangement (210) arranged in the casing (270) comprising: radiation means emitting electromagnetic radiation into the pipe segment (230), and detection means detecting electromagnetic radiation originating from the radiation means, and a flow meter arrangement (220) arranged in the casing (270), the method comprising: measuring (S1 a; S1 b), by the radiation arrangement (210), a concentration of a substance in the bilge water, measuring (S3a; S5b), by the flow meter arrangement (220), a flow of the bilge water, causing (S7a; S4b, S8b), by the control unit (240), a valve of the conduit system (100) to prevent a flow of bilge water through the outlet when at least one of the following criteria is fulfilled: the measured concentration is above a predetermined concentration value, and the measured flow is below a predetermined flow value.

15. The method according to claim 14, further comprising communicating (S4b, S8b) to a user that the measured flow is below the predetermined flow value and / or measured concentration is above the predetermined concentration value.

16. The method according to any one of claims 14-15, wherein the flow meter arrangement (220) is a magnetic flow meter arrangement (220), and the measuring (S3a; S5b) of the flow comprises measuring a difference in electric potential, wherein the difference in electric potential is induced by a flow of bilge water through a magnetic field generated by the magnetic flow meter arrangement (220).

17. The method according to claim 16, further comprising alternating the direction of the magnetic field generated by the flow meter arrangement (220) at a first frequency.

18. The method according to claim 17, wherein the measuring (S1a; S1 b) of the concentration comprises pulsing electromagnetic radiation into the pipe segment (230) at a second frequency, and wherein the first frequency and the second frequency are in phase.

19. The method according to any one of claims 14-18, wherein the arrangement (200) further comprises a computing unit, arranged in the casing and to receive measurement data from the radiation arrangement (210) and the flow meter arrangement (220), the computing unit being arranged to communicate with the control unit (240), the method comprising: receiving, by the computing unit, a measured concentration value, receiving, by the computing unit, a measured flow value, processing the measured concentration value and the measured flow value, communicating a concentration value to the control unit, the communicated concentration value being determined based on at least the measured flow value.

20. The method according to claim 19, wherein processing the measured concentration value and the measured flow value comprises: comparing the measured flow value to the predetermined flow value, when the measured flow is below the predetermined flow value, setting a concentration parameter to a value above the predetermined concentration value or to a maximum value, communicating the concentration value to the control unit by means of the computing unit.

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