The invention relates to a hose arrangement for transferring a flowable medium between a first unit and a second unit in a marine environment. The hose arrangement comprises a hose unit comprising 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.

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 flowable 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 arrangements is that it is difficult to empty the content of the medium in the first conduit while the hose unit is connected between the first unit and the second unit. Accordingly, after the operation of conducting the medium between the two units, there is a risk that the medium is discharged into the environment, such as the sea between the units or the deck of the vessel or the platform. Apart from the possible environmental consequences of such discharge, special adapted fluids, such as drill fluid, are expensive to replace. Even if this is prevented, the remaining medium in the first conduit must in any case be reintroduced into a container for the medium before the hose unit can be used for conducting a different medium or before storing the hose unit in a compact manner. WO2010041955A1 discloses a hose system comprising an inner hose, an outer hose and an air filled volume between the inner hose and the outer hose for providing buoyancy to the hose system.

WO2009/082241 A discloses a safety hose for transferring fluids between a floating structure and another fixed or floating structure.

Summary of the invention

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. In particular, an object of the invention is to provide a hose arrangement that enables the hose unit of a hose arrangement to be evacuated subsequently to its use while being connected between the two units.

These objects are achieved by means of a hose arrangement for transferring a flowable medium between a first unit and a second unit in a marine environment according to claim 1 , wherein the hose arrangement comprises a hose unit comprising 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, wherein 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 hose arrangement is characterized in that it comprises a loop arrangement comprising an inlet for injecting a gas into the space and an outlet for removing the gas from the space, and wherein the hose arrangement further comprises a control unit adapted to control the flow of the medium through the first conduit and the flow of the gas through the loop arrangement, wherein the control unit is adapted to control the flow of the medium through the first conduit and the flow of the gas through the loop arrangement in a shut down phase so that the flow of the medium through the first conduit is terminated before terminating the flow of the gas through the loop arrangement.

The control unit controls the flow of the medium through the first conduit and the gas through the loop arrangement. By means of the control unit, after terminating conducting the medium through the first conduit, gas is injected into the loop arrangement and pressurizing the space with the result that the first conduct is compressed flat within the second conduit. Thereby, the hose arrangement of the invention enable the medium to be evacuated from the first conduit while the hose unit is maintained connected between the first unit and the second unit. Accordingly, the risk of discharge of the medium to the environment is reduced. Furthermore, it is assured that the medium can be discharged to a designated container with reduced risks of spill.

According to an embodiment of the invention, the hose arrangement comprises pressure sensor means that is adapted to sense the pressure of the gas that is being conducted in the loop arrange- ment, and a logic unit adapted to receive information from the pressure sensor means and in dependency of said received information determine a significant change in the pressure that is related to a compressed state of the first conduit.

According to an embodiment of the invention, the significant change comprises a decrease in pressure that is related to a compressed state of first conduit.

According to an embodiment of the invention, the pressure sensor means is arranged to sense the pressure of the gas after that the gas has been conducted through the inlet and the outlet.

By means of determining the significant change in the pressure, the changed to the compressed state of the first conduit can be detected. Accordingly, it can be assured that the first conduit has been compressed to a sufficient degree before disconnecting the hose unit form the first unit and the second unit.

According to an embodiment of the invention, the hose arrangement comprises signalling means for creating an alarm signal and the logic unit is adapted to control the signalling means in dependency of the change to the compressed state of first conduit.

By means of the signalling means, the compressed state of the first conduit can be indicated to an operator of the hose arrangement. Accordingly, after the indicated compressed state of the first conduit, the hose unit can be disconnected from extension between the first unit and the second unit.

The objects of the invention is further obtained by a method for evacuating a hose unit of a hose arrangement. The method comprises the steps of:

- terminating the flow of the medium through the first conduit,

- feeding gas through the loop arrangement, thereby pressurizing the space, and

- maintaining pressurization of the space

According to an embodiment of the invention, the method comprises:

- receiving first information from the pressure sensor means and determining a first pressure,

- receiving second information from the pressure sensor means and determining a second pressure, and

- determining if a significant change in the pressure has occurred by comparing the first pressure and the second pressure.

According to an embodiment of the invention, the method comprises:

- determining the significant change in the pressure if the difference between the first pressure and the second pressure is positive and within a first range, wherein the significant change is related to the change to a compressed state of first conduit. According to an embodiment of the invention, the logic unit receives information on the first pressure and second pressure repeatedly over time.

The object of the invention is further obtain by means of use of a hose arrangement according to the invention.

Brief description of drawings

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

Fig. 6 discloses a flowchart of a first embodiment of a method for evacuating a hose unit of a hose arrangement after termination of conduction of the medium ; and

Fig. 7 discloses a flowchart of a second embodiment of a method for evacuating a hose unit of a hose arrangement after termination of conduction of the medium .

Detailed description of the invention

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 por- tion 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 1 0. 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 a loop arrangement 40 comprising 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 P1 . 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.

Fig. 5 discloses a schematic overview of the hose arrangement 1 according to an embodiment of the invention. The hose arrangement 1 comprises a compressor device 70 for injecting compressed gas into that the loop arrangement 40. Preferably, the compressor device 70 is adapted to inject a stream of air into loop arrangement 40.

The hose arrangement 1 comprises control unit 75 adapted to control the flow of the medium through the first conduit 20 and the flow of the gas through the loop arrangement 40. For example, the control unit 75 controls valves 77, 78 on connections to supply means for the medium and the gas.

The control unit 75 is adapted to control the flow of the medium through the first conduit 20 and the flow of the gas through the loop arrangement 40 in a shut down phase so that the flow of the medium through the first conduit 20 is terminated before terminating the flow of the gas through the loop arrangement 40. By means of conducting the gas through the loop arrangement 40 after terminating the conduction of the medium, the first conduit 20 is compressed by the pressurization of the space 24. Accordingly, medium contained with the first conduit 20 is evacuated from the first conduit 20 while allowing the hose unit 3 to be maintained connected to the first unit 5 and the second unit 7.

The hose arrangement 1 comprises pressure sensor means 80 that is adapted to sense the pressure of the gas that is being conducted in the loop arrangement 40. The pressure sensor means 80 is for example a piezoresistive pressure gauge, a capacitive pressure gauge, an electromagnetic pressure gauge, a piezoelectric pressure gauge, a potentiometric pressure gauge, a resonant pressure gauge, a thermal pressure gauge and an ionization pressure gauge. The pressure sensor means 80 is preferably arranged to sense the pressure of the gas after that the gas has been conducted through the inlet 42 and the outlet 44.

The hose arrangement 1 further comprises a logic unit 82 adapted to receive information from the pressure sensor means 80 and in dependency of said received information determine a significant change in the pressure that is related to a change to a compressed state of first conduit 20. The significant change in the pressure is determined if the difference between the first pressure and the second pressure is positive and within a first range.

During operation of the hose unit, a leakage entering the space 24 is adapted to be evacuated from the hose unit 3 by means of the flow of the gas in the loop arrangement 40. The hose arrangement 1 further comprises a container 90 to which the leakage is adapted to be evacuated. Furthermore, hose arrangement 1 comprises leakage sensor means 92 for sensing a receipt of said leakage in the container 90. The logic unit 82 is adapted to receive information from the leakage sensor means 92 and determine a significant change relating to receipt of the leakage in the container 90.

The leakage sensor means 92 is for example a liquid sensor that detects receipt of a liquid based on change in conductivity, capacitance, optical interface, and etcetera. Alternatively, the leakage sensor means 92 comprises 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.

Preferably, the leakage sensor means 92 is configured to measure an amount of the medium and the logic unit 82 is adapted to determine an extent of the leakage of the medium based on information from the leakage sensor means 92 over time.

In the disclosed embodiment, the hose arrangement 1 further comprise a separation unit 94 in fluid communication with the outlet 44 and means for discharging medium that has been evacuated from the space 24. The separation unit 94 is adapted to separate the medium from the gas. In fig. 5, the hose arrangement 1 comprises a further container 96 and a discharge conduit 98 that is adapted to guide medium from the separation unit 94 to the further container 96 further in the event of extensive leakage that has been evacuated from the space 24.

The hose arrangement 1 further comprises signalling means 99 for creating an alarm signal and the logic unit is adapted to control the signalling means 99 in dependency of the determined significant change. The signalling means 99 is for example 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 99 is for example an indication lamp, a buzzer, a vibration device, and etcetera.

In fig. 6 a flowchart of a first embodiment of a method for evacuating a hose unit 3 of a hose arrangement 1 after termination of conduction of the medium is disclosed.

The method comprises, in a step 1 10, terminating the flow of the medium through the first conduit 20, and in a subsequent step 120, conducting the medium through the first conduit 20. The method further comprises, in a step 120, feeding gas through the loop arrangement 40, thereby pressurizing the space 24, wherein a step 130 comprises maintaining pressurization of the space 24, such as for a predetermined period of time known to be sufficient to compress the first conduit 20 to flat state and thereby evacuating the medium contained therein. In fig. 7 a flowchart of a second embodiment of a method for evacuating a hose unit 3 of a hose arrangement 1 after termination of conduction of the medium is disclosed. The second embodiment in fig. 7 differs from the first embodiment in that the method further comprises, in a step 140, receiving first information from the pressure sensor means 80 and determining a first pressure, and in a step 150, receiving second information from the pressure sensor means 80 and determining a second pressure. The method further comprises the in a step 160 determining if a significant change in the pressure has occurred by comparing the first pressure and the second pressure. The significant change in the pressure is determined if the difference between the first pressure and the second pressure is positive and within a first range. The significant change is related to the change to a compressed state of first conduit 20. The method further comprises, in a step 170, if the significant change has been determined, terminating feeding gas through the loop arrangement 40. By means of the second embodiment, the evacuation of the hose unit 3 after termination of conduction of the medium can be executed in an automated manner.

It should be noted that the above-mentioned embodiments illustrate 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.