Introduction

The present invention relates to an elongated hose unit for transferring a flowable medium between a first unit and a second unit in a marine environment. The hose unit comprises a first end portion adapted to be connected to the first unit and a second end portion adapted to be connected to the second unit. The hose unit further comprises a first conduit adapted to transfer the medium and a second conduit arranged around the first conduit so that a closed space is formed between the first conduit and the second conduit. The space extends along at least a part of the length of the hose unit and is adapted to receive the medium in case of a leakage.

The present invention further relates to a hose arrangement comprising the hose unit and a method for evacuating a leakage of the flowable medium from the hose unit.

Prior art

Hose units are used in variously industrial applications, such as marine environment, for transferring a flowable medium between a first unit and a second unit. For example, in off-shore oil production, large amount of flowable medium is produced that needs to be transported for further processing. Large amount of fluids are also used in the production and accordingly needs to be transferred to the production site. Flexible hose units are in particular suitable for transferring flow- able medium in a dynamic environment, such as between an oil rig and a vessel.

The flowable medium may be a liquid or a flowable solid, such as powder with grain size that enables it to be transferred using the hose unit. The flowable medium may also comprise a mixture of different phases, such as a slurry of liquid and solids. These solids may be abrasive and result in internal fractures in the hose unit. The medium is for example oil, water, drilling fluid, drilling mud, and etcetera.

A problem with prior art hose units is that it is difficult to detect small leakage of the hose unit during transferring the medium between the two units. Prior art leak detection is based on determining a difference between the amount of the medium transferred from one of the units and the amount received by the other of the two units. In that the hose unit normally is used for transferring large aammoouunntt ooff tthhee fflloowwaabbllee mmeeddiiuumm aatt aa hhiigghh ffllooww rraattee,, aa ssmmaallll lleeaakkaaggee ooff tthhee mmeeddiiuumm iiss uussuuaallllyy nnoott ddeetteeccttaabbllee..

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The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art. A first object of the invention is to provide a hose unit that enables a leakage of the medium to be evacuated. A second object of the invention is to provide a hose unit that enables small internal leakage of the medium to be detected. A third object of the invention is to provide a hose unit that enables a leakage of the medium to be notified and quantified.

These objects are achieved by means of an elongated hose unit according to claim 1. The hose unit is characterized in that the hose unit comprises an evacuation arrangement for evacuating the medium from the space, the evacuation arrangement comprises an inlet for injecting a gas into the space so that the space is pressurized to a first pressure and an outlet for removing the gas and possible medium from the space, wherein the outlet extends from the space to an outside that comprises a second pressure that is lower than the first pressure. The hose unit is a flexible arrangement for transferring the medium between the first and the second unit. Accordingly, the hose unit is configured to flexible extend between the two units and to be coiled on a drum for storage when the hose unit is not in use. The flexibility of the hose unit is of particular advantage for the transferring medium in a dynamic environment, such as between an oil rig and a vessel.

The space between the first and the second conduit is adapted to receive the medium in case of a fracture at the first conduit that results in an internal leakage. The evacuation arrangement is configured to evacuate the space from possible medium that has leaked into the space by means of that gas is injected through the inlet resulting in that the space is pressurized to a first pressure. The evacuation arrangement further comprises an outlet from the space to an outside that comprises a second pressure that is lower than the first pressure. The second pressure is for example the ambient air pressure and the pressure difference between the first and the second pressure is determined by the applied stream of the gas into the space. Possible medium that has leaked to the space is accordingly evacuated to the outside through the outlet due to the pressure difference between the first and the second pressure.

The invention has the advantage that medium that has leaked in to the space can be evacuated from the space while the hose unit is used for transferring the medium between the first and the second unit. In case of a small leakage, it is possible to fulfil the transferring operation of the medium before replacing and repairing the hose unit. Accordingly, the hose unit improves the operation of the hose unit. The invention has further the advantage that a leakage of the medium can be detected at an early stage before resulting in a catastrophic rupture of the hose unit with significant leakage of the medium to the surrounding.

According to an embodiment of the invention, the inlet comprises a third conduit.

According to an embodiment of the invention, the outlet comprises a fourth conduit.

According to an embodiment of the invention, the fourth conduit comprises a first opening to the space and a second opening to the outside, and where fourth conduit extends from the first opening to the second opening at the first end portion or the second end portion of the hose unit. By arranging the fourth conduit to one of the end portions of the hose unit, the medium is evacuated to the first or the second unit for further storing. According, in the event of a leakage, the medium is prevented from being released to the surrounding of the hose unit.

According to an embodiment of the invention, the first opening to the space is arranged at or in vicinity to a center of mass of the hose unit in its fully extended configuration in use. The hose unit is flexible in that it can be coiled, bended and guided to certain positions on the first and the second unit. When the hose unit extends between the first and the second unit, the center of mass of the hose unit will constitute the lowest point. Accordingly, in the event of a leakage, the medium will flow to the center of mass of the hose unit when the hose unit is in its fully extended configuration. Accordingly, by arranging the fourth conduit so that the first opening is starting at or in vicinity to a center of mass of the hose unit, when this is in its fully extended configuration, it is assured that the medium will be evacuated as soon as a leakage has occurred.

According to an embodiment of the invention, the fourth conduit extends along a major part of the length of the hose unit.

According to an embodiment of the invention, the third conduit comprises a third opening to the space and a fourth opening for providing the gas, and where the third conduit extends from the third opening to the fourth opening at the first end portion or the second end portion of the hose unit. By providing the pressurized gas at the first or the second end portions of the hose unit, the third conduit is arranged at a position at one of the first and second unit, where means for providing pressurized gas normally is available.

According to an embodiment of the invention, the third conduit extends along a major part of the length of the hose unit.

According to an embodiment of the invention, the fourth and third conduit extend from the respective first opening and third opening to the respective second opening and fourth opening at the same end portion of the hose unit. By arranging both the fourth and third conduit so they extends from the same end portion of the hose unit, only one of the two end portion is of special design and the other end portion can be of known standard.

According to an embodiment of the invention, the hose unit comprise a first hose portion, a second hose portion and a connection device between the first and the second hose portion, wherein the connection device comprises a stress release unit and at least a part of the space is arranged in the connection device and the respective opening of the iniet and the outlet is arranged in said at least part of the space. The stress release unit is normally arranged at a center of mass of the hose unit in its fully extended configuration in use.

According to an embodiment of the invention, the stress release unit is a breakaway unit adapted to release the connection between the first and the second hose portion in the event that the stress subjected to the breakaway unit exceed a certain level.

According to an embodiment of the invention, the outlet comprises one first opening at the first hose portion and another first opening at the second hose portion. The primary first opening is adapted to evacuate a possible leakage of the medium from the first hose portion. The secondary first opening is adapted to evacuate a possible leakage of the medium from the second hose portion.

According to an embodiment of the invention, the space has a dimension that enables at least a part of the hose unit to float at the surface of the sea when the space is provided with the gas.

According to an embodiment of the invention, a pressure difference between the first and the second pressure is in the range 0.5 - 20 bar, preferably 2-10 bar. The pressure difference to enable the medium to be evacuated is dependent on the mass of the medium, the difference in elevation between the space and the end portion of the hose unit to which the medium is to be evacuated, and etcetera.

The objects of the invention are further achieved by means of a hose arrangement according to claim 11 , The hose arrangement comprises a hose unit as described above, wherein the hose arrangement further comprises a compressor unit connected to the inlet for providing pressurized gas into the space.

According to an embodiment of the invention, the compressor unit is adapted to provide pressurised air into the space.

According to an embodiment of the invention, the hose arrangement comprises a detection unit comprising a sensor device for detecting receipt of medium that has been removed from the space, signalling means and a logic unit that is adapted to receive information from the sensor device and generate a control signal in dependency of the received information to the signalling means for creating an alarm signal. By means of the detection unit, receipt of the medium from the space is detected and an operator is notified on the leakage by generating the alarm signal.

According to an embodiment of the invention, the signalling means is adapted to create the alarm signal in form of one of a visual signal, an audible signal, and a vibration signal, or a combination thereof. The signalling means is for example an indication lamp, a buzzer, a vibration device, and etcetera.

According to an embodiment of the invention, the pressurized gas is adapted to be injected continuously to the space. Thereby, a continuously detection of a possible leakage of the medium is obtained. Furthermore, in the event of a leakage, the space is evacuated immediately.

According to an embodiment of the invention, the detection unit comprises a display unit, and where the logic unit is adapted to determine an extent of the leakage of the medium based on information from the sensor device and transmit information on the determined leakage to the display unit, wherein the display unit is adapted to display said information.

According to an embodiment of the invention, the evacuation arrangement comprises a separation unit adapted to receive a mixture of the medium and the gas from the space, and separate the medium from the gas. By means of separating the medium from the gas, the medium can, after the leakage of the hose unit has been repaired or the hose unit has been replaced, again be transferred between the first and the second unit. The objection of the invention is further achieved by means of a method for evacuating a leakage of a flowable medium from a hose unit according to claim 15, wherein the hose unit comprises a closed space between a first conduit and a second conduit. The method comprises the steps of

- injecting a gas into the space so that the space is pressurized to a first pressure, and

- evacuating the gas and possible medium from the space by allowing the gas and possible medium to be conducted to an outside that comprises a second pressure that is lower than the first pressure.

According to an embodiment of the invention, the method comprises continuously injecting and evacuation the gas to/from the space.

According to an embodiment of the invention, the method further comprises the steps of

- measuring a physical property that is dependent on the receipt of medium that has been removed from the space,

- detecting a significant change in said physical property that corresponds to a leakage of the medium, and

- generating a control signal for creating an alarm signal in dependency of the detection of said significant change.

According to an embodiment of the invention, the method further comprises the steps of generating a further control signal for terminating a flow of the medium through the hose unit in dependency of said significant change. If the leakage of the medium exceeds certain level where a repair or replacement of the hose unit is desirable, the further control signal will be generated that terminates the flow of the medium. The generation of the control signal also assures that the flow of the medium is terminated in case of a catastrophic rupture of the hose unit.

According to an embodiment of the invention, the method further comprises the steps of

- measuring the physical property that is dependent on a quantity of the medium that has been removed from the space,

- determining the quantity of the medium that has been removed from the space during a period of time, and

- displaying the determined quantity of the medium that has been removed from the space during the period of time.

According to an embodiment of the invention, the method further comprises the steps of generating a further control signal for terminating a flow of the medium through the hose unit if the determined quantity of the medium that has been removed from the space during the period of time, exceeds a certain level. The control signal may be generated based on the amount of leakage of the medium.

According to an embodiment of the invention, the method further comprises the steps of generating yet another control signal for creating a further alarm signal if the determined quantity of the medi- urn that has been removed from the space during the period of time exceeds a certain level.

In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1 discloses a hose arrangement according to an embodiment of the invention, where a hose unit extends between a first and a second unit;

Fig. 2 discloses an example of the hose unit in fig, 1 ;

Fig. 3 discloses a cross section of an example of an intermediate portion of the hose unit in fig. 2;

Fig. 4a discloses a cross section of an example of a stress release unit of the hose unit in fig. 2, where the stress release unit is in an engaged state;

Fig. 4b discloses a cross section of the stress release unit in fig. 4a, where the stress release unit is in a disengaged state;

Fig. 5a discloses a cross section of an example of an end portion of the hose unit in fig. 2, where the end portion is connected to the connection device of the first unit;

Fig. 5b discloses a cross section of the end portion in fig. 5a, where the end portion is disconnected from the connection device of the first unit;

Fig. 6 discloses a schematic overview of the hose arrangement according to an embodiment of the invention;

Fig. 7 discloses a flowchart of a first embodiment of a method for evacuating a leakage of a flowable medium from a hose unit; and

Fig. 8 discloses a flowchart of a second embodiment of a method for evacuating a leakage of a flowable medium from a hose unit.

Fig. 1 discloses an overview of a hose arrangement 1 according to an embodiment of the invention. The hose arrangement 1 comprises an elongated hose unit 3 for transferring a flowable medium between a first unit 5 and a second unit 7. The hose unit 3 extends between the first unit 5 and the second unit 7. The hose unit 3 further comprises a stress release unit 10, such as a breakaway unit. In fig. 1 , the first unit 5 comprises an oil rig and the second unit 7 comprises a vessel.

The hose unit 3 comprises a first end portion 12 connected to the first unit 5 and a second end portion 14 connected to the second unit 7. In fig. 2, the embodiment of the hose unit 3 in fig. 1 is disclosed in further details, where a part of the hose unit 3 is stored on a storage drum 16.

Fig. 3 discloses a cross section at an example of an intermediate portion 18 of the hose unit 3 in fig. 2. The intermediate portion 18 of the hose unit 3 constitutes a main part of the extension of the hose unit 3. The hose unit 3 comprises a first conduit 20 adapted to guide the medium when the medium is transferred between the first unit 5 and the second unit 7. The hose unit 3 further comprises a second conduit 22 arranged around the first conduit 20 in order to protect the first conduit 20 from fracture due to abrasion or hits to its exterior surface. The second conduit 22 is further arranged so that a closed space 24 is formed between the first conduit 20 and the second conduit 22. The space 24 extends along the extension of the hose unit 3. Preferably, the first conduit 20 and the second conduit 22 comprise a uniform wall thickness along the extension of the hose unit 3. Accordingly, the space 24 is preferably uniformly arranged along the extension of the hose unit 3.

Referring to fig. 1 , 2, 4a and 4b, the hose unit 3 comprises a first hose portion 26 and a second hose portion 28 that are connected with each other by means of the stress release unit 10. The stress release unit 10 has the function to release the connection between the first hose portion 26 and the second hose portion 28 in the event that stress release unit 10 is subjected to a stress that exceeds a certain value, in fig. 4a the stress release unit 10 is in an engaged state, where the first hose portion 26 and the second hose portion 28 are connected. In fig. 4b the stress release unit 10 is in a disengaged state, where the first hose portion 26 and the second hose portion 28 are disconnected from each other.

An example of a cross section of the stress release unit 10 is disclosed in further detail in fig. 4a and 4b. The hose unit 3 comprises a further portion 30 of the space 24 that is adapted to receive the medium in case of a leakage of the first conduit 20. In particular, the further portion 30 of the space 24 is adapted to be arranged at a centre of mass M of the hose unit 3 in its fully extended configuration. Accordingly, when the hose unit 3 extends between the first unit 5 and the second unit 7, the further portion 30 of the space 24 will constitute the lowest point of the hose unit 3. In case of a leakage anywhere along the length of the hose unit 3, the medium will flow to the further portion 30 of the space 24.

The hose unit 3 further comprises an evacuation arrangement 40 for evacuating the medium from the space 24. The evacuation arrangement 40 comprises an inlet 42 to the space 24 and an outlet 44 from the space 24. The inlet 42 is adapted to guide a stream of pressurized gas, such as air, into the space 24. The outlet 44 is adapted to guide the gas and possible leakage of the medium out of the space 24.

The injection of the stream of gas is into the space 24 is adapted to pressurize the space 24 to a first pressure PL The outlet 44 is arranged extending to an outside that comprises a second pressure P2 that is lower than the first pressure P1. Accordingly, due to the pressure difference be- tween the space 24 and the outside, possible leakage of the medium will be transferred to the outside by means of the outlet 44 of the evacuation arrangement 40. Preferably, the second pressure P2 relates to the ambient air pressure and the first pressure P1 is set by the rate of injection of the stream of gas.

The inlet 42 comprises a third conduit 50 and the outlet 44 comprises a fourth conduit 52, see fig. 3. The fourth conduit 52 extends between a first opening 54 to the space 24 and a second opening 56 at the first end portion 12 of the hose unit 3. The third conduit 50 extends between a third opening 58 to the space 24 and a fourth opening 60 at the first end portion 12 of the hose unit 3.

The evacuation arrangement 40 is arranged so that the third opening 58 to the space 24 and the first opening 54 from the space 24 are separated from each other by a distance within the space 24. In fig. 4a and 4b the third opening and the first opening 54 are arranged at the further portion 30 of the space 24. In fig. 4a and 4b, the outlet 44 comprises two first opening 54 to the space 24, one at the first hose portion 26 and another at the second hose portion 28. Thereby, the invention enables the space 24 of both the first hose portion 26 and the second hose portion 28 to be evacuated.

In fig. 4a and 4b, the stress release unit 10 comprises means for closing openings to the first conduit 20, the third conduit 50 and the fourth conduit 52 in the event that the stress release unit 10 is changed from the engaged state to the disengaged state.

The first conduit 20, the second conduit 22, third conduit 50 and fourth conduit 52 comprise mainly an elastic material that enables the hose unit 3 to be bended for facilitating connection to specific locations on the first unit 5 and the second unit 7, and to be coiled on the storage drum 16. The material comprises for example mainly a polymeric material, such as one of nylon, polyurethane, polyethylene, PVC, and synthetic or natural rubbers, or mixture thereof. Fig. 5a discloses a cross section of the first end portion 12 of the hose unit 3 in fig, 2, where the first end portion 12 is connected to a connection unit 70 of the first unit 5. Fig. 5b discloses a cross section of the first end portion 12 of the hose unit 3 in fig. 2, where the first end portion 12 is disconnected from the connection unit 70.

The first end portion 12 comprise means for being connected to a connection unit of the first unit 5. The first end portion 12 comprise means for connecting the first conduit 20, the third conduit 50 and the fourth conduit 52 to a respective corresponding conduit 20a, 50a, 52a of the connection unit 70. The connection unit 70 further comprises a further inlet 80 and a further outlet 82 for providing a controllable quick release coupling of the hose unit to the first unit 5 or the second unit 7.

In fig. 5b, the first end portion 12 of the hose unit 3 has been disconnected from the connection unit 70. The flow of the medium in the first conduit 20 has been terminated. Likewise has the injection of gas through the third conduit 50 and removal of gas and possible leakage of the medium been terminated.

Fig. 6 discloses a schematic overview of the hose arrangement 1 according to an embodiment of the invention. The hose arrangement 1 comprises a compressor device 100 for injecting compressed gas to the space 24 of the hose unit 3 by means of the inlet 42 to the second end portion 28 so that the space 24 is pressurized to the first pressure P1 , Preferably, the compressor device 100 is adapted to inject a stream of air into the space 24.

The hose arrangement 1 further comprise a separation unit 105 in fluid communication with the outlet 44 and means for discharging medium that has been evacuated from the space 24. The separation unit 105 is adapted to separate the medium from the gas. In fig. 6, the hose arrangement 1 comprises a container 110 and a discharge conduit 112 that is adapted to guide medium from the separation unit 105 to the container 1 10 in the event of a leakage that has been evacuated from the space 24.

The hose arrangement 1 further comprises a detection unit 120 for detecting receipt of medium that has been removed from the space 24. The detection unit 120 comprises a sensor device 121. In the disclosed embodiment of the invention, the sensor device 121 is arranged in a further container 114. The sensor device 121 is for example a liquid sensor that detects receipt of a liquid based on change in conductivity, capacitance, optical interface, and etcetera.

According to a preferred embodiment of the invention, the detection unit 120 comprises a chamber with a float that is adapted to be displaced between a first and a second position relating to no leakage and a leakage of the medium respectively. According to an alternative embodiment, the evacuated medium is transferred back to its original source, such as a tank. In this case, the sensor unit 120 may for example comprise an optical sensor.

The detection unit 120 further comprises a logic unit 122 and signalling means 124. The logic unit 122 is adapted to receive information from the sensor device 121 and generate a control signal to the signalling means 124 in dependency of the received information. The signalling means 124 is adapted to generate an alarm upon receipt of the control signal. The signalling means 124 is for example an indication lamp, a buzzer, a vibration device, and etcetera.

The sensor device 121 is configured to measure an amount of the medium and the logic unit 122 is adapted to determine an extent of the leakage of the medium based on information from the sensor device 121 over time. The detection unit 120 further comprises a display unit 126 that is adapted to receive information on the determined rate of leakage and transmit information on the determined rate of leakage for display by the display unit 126.

Fig. 7 discloses a flowchart of a first embodiment of a method for evacuating a leakage of a flowa- ble medium from a hose unit 3. The method is initiated in a step 210 by injecting a gas into the space 24 and a step 220 by evacuating the gas and possible medium from the space 24. The gas is injected so that the space 24 is pressurized to a first pressure P1. The evacuation of the space 24 is arranged by enabling the gas and possible medium to be conducted to an outside that comprises a second pressure P2 that is lower than the first pressure P1. The process of injecting and evacuating of the gas to/from the space 24 are preferably performed simultaneously. Likewise, the injection and evacuation of the gas to/from the space 24 are preferably performed continuously.

In a step 230, the method comprises measuring a physical property that is dependent on the receipt of medium that has been removed from the space 24. In a step 240, the method comprises detecting a significant change in the physical property that corresponds to a leakage of the medium. The measuring of the physical property and detection of the significant change is preferably performed simultaneously.

In a step 250, if the significant change has been detected, the method proceeds to a step 260 in which an alarm signal is generated by means of that the logic unit 122 generates a control signal to the signalling means 124 for creating the alarm signal. If no significant change is detected, the method is iterated from step 210. Step 260 is followed by a step 270 in which the logic unit 122 generates a further control signal for terminating the flow of the medium through the hose unit 3. Thereafter the method is stopped.

Fig. 8 discloses a flowchart of a second embodiment of a method for evacuating a leakage of a flowable medium from a hose unit 3.

The method in fig. 8 differs from the embodiment in fig. 7 in that the method further comprises steps 262, 264, 266, 268 and 269. After the significant change has been detected and the control signal in step 260 has been generated for creating an alarm signal, the method proceeds in a step 262 by measuring a physicai property that is dependent on a quantity of the medium removed from the space 24. In a step 264, the method comprises determining the quantity of the medium that has been removed from the space 24 during a period of time.

The physical property may be the same as is used for detecting the significant change that is dependent on receipt of the medium. Alternatively, a separate physical property may be used for determining the quantity of the medium removed from the space 24.

In a step 266, the method comprises displaying the quantity of the medium that has been removed during the period of time. The quantity per period of time is for example volume per time unit, such as mL/minute, mass per time unit, such as kg/minute, and etcetera.

In a step 268, the method comprises determining if the quantity exceeds a predetermined level in which operation of the hose unit 3 is not desirable. If the quantity exceeds the predetermined level, the method proceeds to a step 269 in which the logic unit 122 generates a yet another control sig- nai to the signalling means 124 for creating a further alarm signal. If the determined quantity does not exceed the certain level, the method is iterated from step 210. Step 269 is followed by a step 270 in which the logic unit 122 generates a further control signal for terminating the flow of the medium through the hose unit 3. Thereafter the method is stopped. It should be noted that the above-mentioned embodiments iliustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.