CENTRIFUGAL PUMP FOR HEATING FLUID BY EDDY CURRENT, AND SUBSEA TOOL FOR HEATING FLUID BY EDDY CURRENT

Abstract

The present invention provides a centrifugal pump for heating fluid by eddy current comprising a volute (29) and a cover (34), in which internally regarding the volute (29) there are provided: an impeller (33) positioned between two supporting annular disks (32) of magnets each comprising a plurality of permanent magnets (31); and two armatures (30) positioned at the ends of the internal assembly. In addition, the invention also provides a subsea tool for fluid heating by eddy current comprising: a centrifugal pump (1) driven by a hydraulic motor (3) by means of a shaft (11); a fluid storage tank (2) hydraulically connected to the centrifugal pump (1); at least one piloted on-off valve (4); piloted directional valves (12, 13); and a filter (7) hydraulically connected to the centrifugal pump (1).

Claims

1. A centrifugal pump for fluid heating by eddy current, comprising: a volute and a cover, in which internally regarding the volute there are provided; an impeller positioned between two supporting annular disks of magnets each comprising a plurality of permanent magnets; and two armatures positioned at the ends of the internal assembly.

2. The centrifugal pump according to claim 1, wherein the volute and the cover are made of a material with low thermal conductivity and high mechanical strength.

3. The centrifugal pump according to claim 2, wherein the impeller is made of a material with good thermal and electric conductivity, and the armature is made of a material with high magnetic permeability.

4. The centrifugal pump according to claim 1, wherein the magnets are positioned so as to have opposite polarity with respect to the neighboring magnets.

5. The centrifugal pump according to claim 1, the annular discs supporting the magnets comprise cavities with the same geometry as the magnets.

6. The centrifugal pump according to claim 1, wherein the impeller is rotated within a magnetic field generated by the magnets, generating an eddy current in the impeller body.

7. A subsea tool for fluid heating by eddy current, comprising: a centrifugal pump driven by a hydraulic motor by a shaft; a fluid storage tank hydraulically connected to the centrifugal pump; at least one piloted on-off valve; piloted directional valves; and a filter hydraulically connected to the centrifugal pump, wherein the centrifugal pump is as defined by claim 1.

8. The subsea tool according to claim 7, further comprising temperature sensors adapted to measure the temperature of the inlet fluid and the outlet fluid of the centrifugal pump; and a rotation sensor adapted to measure the rotation of the shaft of the hydraulic motor, wherein the data generated by the sensors are sent to an electronic bottle, wherein the electronic bottle-comprises a hermetic vessel, with elastomeric seals, resistant to the collapse pressure, wherein inside there are electronic pieces of equipment for interpreting the signals from the sensors, encoding and sending the same to the ROV.

9. The subsea tool according to claim 7, wherein the piloted on-off valve is of the two-way, two-position type, normally closed with spring return, and is hydraulically piloted by a pressure line.

10. The subsea tool according to claim 7, wherein the hydraulic motor comprises a feed line connected to the control valve and a feed line connected to the return line for the ROV tank.

11. The subsea tool according to claim 7, further comprising a directional valve installed upstream of the pump, wherein the directional valve is adapted to select the source of the fluid inserted into the pump through a fluid inlet opening, wherein the fluid can be drawn from the fluid storage tank or from the filter, and wherein the directional valve comprises hydraulic piloting in both directions, wherein the piloting of the directional valve is done by an ROV.

12. The subsea tool according to claim 7, further comprising a directional valve installed downstream of the pump, at the heated fluid outlet, adapted to direct the heated fluid outlet to the tank or to an external piece of equipment, wherein the valve is hydraulically piloted in both directions.

13. The subsea tool according to claim 7, wherein the fluid accumulation tank is of the compensated type, with variable internal volume, with coatings of materials that provide thermal insulation, and comprising thrust compensators.

14. The subsea tool according to claim 7, wherein the tool is installed on a structure attached to an ROV, wherein the structure is located at the bottom or at the rear of the ROV.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0033] The detailed description presented below makes reference to the attached figures and their respective reference numbers.

[0034] FIG. 1 illustrates a schematic diagram of an optional configuration of the subsea tool for fluid heating by eddy current of the present invention.

[0035] FIG. 2 illustrates a view of an electronic bottle according to an optional configuration of the present invention.

[0036] FIG. 2a illustrates the fluid storage tank illustrated in FIG. 1 in the empty condition.

[0037] FIG. 3 illustrates a centrifugal pump with fluid heating by eddy current function according to an optional configuration of the present invention.

[0038] FIG. 3a schematically illustrates the polarity arrangement of the magnets responsible for inducing eddy currents in the pump impeller illustrated in FIG. 3.

[0039] FIGS. 4a and 4b illustrate two possible embodiments of mounting the tool of FIG. 1 in the structure of an ROV.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Preliminarily, it should be noted that the following description will start from a preferred embodiment of the invention. As will be apparent to any technician skilled on the subject, however, the invention is not limited to that particular embodiment.

[0041] Considering the demand for more effective methods of dissociating hydrates in an external environment to the subsea pieces of equipment, cleaning surfaces and removing heat-sensitive scales (paraffins, greases, resins and the like), and also considering the space restriction available in the structure of the ROV and the availability of hydraulic power, the invention that will be described below consists of a simple tool, installed and operated by an ROV.

[0042] FIG. 1 illustrates a schematic diagram of an optional configuration of the subsea tool for fluid heating by eddy current of the present invention. In this figure, it is possible to observe the interconnection between the various components of the tool.

[0043] In general, the tool comprises: a modified centrifugal pump with heating function 1; a fluid storage tank 2; a hydraulic motor 3; a piloted on-off valve 4; piloted directional valves 12, 13; a filter 7; temperature sensors 8, 14; and a rotation sensor 10.

[0044] FIG. 2 illustrates a view of an electronic bottle 28 according to an optional configuration of the present invention. FIG. 2a illustrates the fluid storage tank 2 of FIG. 1 in the empty condition.

[0045] More generally, the fluid storage tank 2 comprises a hermetic bottle 28, resistant to collapse, containing the electronics responsible for reading signals from sensors that make up the invention.

[0046] The details of these elements will be presented and described in detail later in this specification.

[0047] FIG. 3 illustrates a centrifugal pump 1 with fluid heating by eddy current function according to an optional configuration of the present invention. FIG. 3a schematically illustrates the polarity arrangement of the magnets responsible for inducing eddy currents in the pump impeller.

[0048] It is observed that the pump consists of a volute 29 and a cover 34, optionally manufactured in a material of low thermal conductivity and good mechanical strength. The pump 1 further comprises internally regarding the volute 29 an impeller 33 positioned between two annular support discs 32 of magnets each comprising a plurality of permanent magnets 31, and two armatures 30 positioned at the ends of the internal assembly.

[0049] Thus, the volute 29 and the cover 34 provide good thermal insulation to the pump 1, preventing heat loss to the external environment and increasing the efficiency in heating the pumped liquid, as will become more evident with the following description.

[0050] In addition, the impeller 33 is preferably made of a material with good thermal and electric conductivity.

[0051] The ring disks 32 of magnet support have the function of holding the magnets 31 and reducing free spaces.

[0052] The armature 30 optionally consists of a material with good magnetic permeability.

[0053] From this configuration, the heating principle of the pumped liquid is given by the combination of the effects of induced electric current (eddy or Foucault current), Joule effect and heat transfer, mainly by the forced convection between the impeller (hot part) and the fluid (cold part). Also, the induced electric current is due to the positioning of the magnets, as will be further detailed in this specification.

[0054] In this way, inside the modified pump, the fluid is pumped while generating and transferring heat to the same.

[0055] FIGS. 4a and 4b illustrate two possible embodiments of mounting the tool of FIG. 1 on the structure of an ROV 35. According to these optional embodiments, the tool can be applied to a structure attached to the bottom (FIG. 4a), or to a structure attached to the rear (FIG. 4b) of an ROV 35.

[0056] The details and alternative configurations will be presented below, based on the configurations shown in the attached figures.

[0057] Optionally, the control valve (piloted on-off valve 4) of the subsea tool for fluid heating by eddy current represented in FIG. 1 is of the two-way, two-position type, normally closed with spring return, and is hydraulically piloted through the pressure line 18.

[0058] The function of the piloted on-off valve 4 is to allow the passage of hydraulic fluid from the high pressure/high flow rate line 21 of the ROV to feed the hydraulic motor 3. In other words, the hydraulic line 18, when pressurized, has as a final objective to turn on the modified bomb 1.

[0059] The subsea tool for fluid heating by eddy current further comprises a hydraulic motor 3 comprising feed lines connected to the control valve 4 and the return line 22 to the ROV tank. The hydraulic motor has the function of supplying mechanical energy to a shaft 11 of the modified pump 1.

[0060] The shaft 11 of the modified pump 1 has the main function of transmitting mechanical power to the impeller 33 of the pump 1. In addition, the shaft 11 can serve as a monitoring element for the rotation of the pump 1 with the use of a rotation sensor 10.

[0061] Thus, a rotation sensor 10 can also be adopted with the function of detecting the movement of the shaft 11 and sending the recorded signals to an electronic bottle 28, through an electric cable 19, or another form of communication.

[0062] The centrifugal pump 1 of the present invention is adapted to perform the pumping of liquid by means of a centrifugal impeller 33, as already presented earlier in this specification, which is positioned between two matrices of permanent magnets 31.

[0063] In addition, the magnets 31 are arranged so that an electric current is induced in the impeller. In other words, the magnets 31 are positioned so as to comprise opposite polarity with respect to neighboring magnets.

[0064] Additionally, an armature 30 consisting of a material with good magnetic permeability is in contact with the magnets 31.

[0065] Thus, the annular disks 32 of supporting magnets 31 have the function of holding the magnets 31 in their positions and filling the spaces between the same. For this, the annular disks 32 supporting the magnets 31 optionally comprise cavities with the same geometry as the magnets 31.

[0066] Thus, during the operation of the centrifugal pump 1, the impeller 33 is rotated within a magnetic field generated by the magnets 31, in order to generate an eddy current in the impeller body 33, an effect known as Foucault current.

[0067] Combined with the Joule effect, electric energy is converted into heat, which heats the impeller 33, so that heat is transferred to the pumped fluid by thermal dissipation. Thus, the fluid is heated extremely efficiently and without the need for a large expenditure of energy.

[0068] The subsea tool for fluid heating by eddy current further comprises a directional valve 12 installed upstream of the pump 1, adapted to select the origin of the fluid inserted into the pump 1 through the fluid inlet opening 26. Thus, fluid can be drawn from the fluid storage tank 2 or from the filter 7.

[0069] Optionally, as seen in FIG. 1, the directional valve 12 has hydraulic piloting in both directions, in which the piloting of this valve 12 is done by the ROV 35.

[0070] Thus, when the hydraulic line 16 is pressurized at the same time as the hydraulic line 6 is depressurized, the pump 1 collects the fluid from the filter 7.

[0071] On the other hand, when the hydraulic line 16 is depressurized at the same time as the hydraulic line 6 is pressurized, the pump 1 collects the fluid from the tank 2.

[0072] A second directional valve 13 can still be installed downstream of the pump, at the heated fluid outlet 25, to direct the outlet of the heated fluid. The fluid can also be directed to the tank 2 or to the external piece of equipment 19.

[0073] As seen in FIG. 1, the valve 13 has hydraulic piloting in both directions. The piloting of this valve is also done by the ROV 35, according to the preferred embodiment described herein.

[0074] Accordingly, when the hydraulic line 15 is pressurized at the same time as the hydraulic line 5 is depressurized, the pump 1 sends heated and pressurized fluid to the external piece of equipment 19.

[0075] On the other hand, when the hydraulic line 15 is depressurized at the same time as the hydraulic line 5 is pressurized, the pump 1 sends the heated fluid to the tank 2.

[0076] The invention further provides that the piloting of valves 12, 13 is not limited only to the described configuration (by hydraulic pressure). Piloting can also be performed by solenoids. A technician skilled on the subject will be able to determine the best form of embodiment according to each application.

[0077] Optionally, a pump output temperature sensor 9 is installed downstream of the pump 1, where the signal from the temperature sensor 9 is sent to the electronic bottle 28 via the electric cable 14.

[0078] Additionally, a pump inlet temperature sensor 8 can be installed upstream of the pump 1. The signal from the temperature sensor 8 is also sent to the electronic bottle 28 via the electric cable 17.

[0079] The electronic bottle 28 receives this designation because it is a hermetic vessel, with elastomeric seals, resistant to the collapse pressure, wherein inside there are contained electronic pieces of equipment responsible for interpreting the signals from the sensors 8, 9, 10 via the electric cables 14, 17, 19, encoding and sending the same to the ROV via the electric cable 27.

[0080] Thus, the electronic bottle 28 represents a data control and interpretation system, contained in a water and pressure resistant container, which can control several elements of the described system.

[0081] The fluid accumulation tank 2 is optionally of the compensated type, with variable internal volume via piston with seals. In this case, the tank 2 would be of the tight type, with coatings of special materials that provide thermal insulation and thrust compensators (floats). Thus, the tank would be able to maintain the temperature and pressure of the liquid inside the same constant, or within desirable ranges during operation.

[0082] The description in the previous paragraph can be better observed by comparing the tank 2 illustrated in FIGS. 1 and 2a, presented above. In FIG. 1, the tank 2 is illustrated with the piston extended, a situation that occurs when the tank 2 is full. In FIG. 2a, in turn, the tank 2 is shown with the plunger retracted, in which case tank 2 would be empty.

[0083] Thus, according to everything described so far, the combination of the states of the valves 12, 13 of the subsea tool for heating fluid by eddy current of the present invention allows the following operating conditions: [0084] a) filling the tank by collecting fluid by means of the filter 7 and ejecting it into the tank via the inlet opening 24 of the tank 2; [0085] b) emptying the tank 2 by means of the collection of fluid internal to the tank 2, via the outlet opening 23 of the tank 2 and ejection to the piece of equipment 19; [0086] c) fluid recirculating by means of fluid collection via the outlet opening 23 of the tank 2 and ejection to the tank 2 via the inlet opening 24; and [0087] d) continuously ejecting by means of the collection of fluid by means of the filter 7 and direct ejection to the piece of equipment 19.

[0088] In all the operations described in the previous paragraphs, the fluid is directed to the centrifugal pump 1 with the function of heating the fluid by eddy current described above so that the heating of the fluid is performed.

[0089] As any technician with minimal knowledge of the subject would know, the collection inlet 20 of the filter 7 can be opened to the seabed or be connected to another tank via a hose and/or hot stab connectors. It can work with different types of fluids: sea water, glycols or water-based hydraulic fluids.

[0090] Additionally, the output of the piece of equipment 19 can be connected to a hose with or without thermal insulation, with its open end or with a hot stab connector, for discharge of the heated fluid on the surface of the subsea piece of equipment or injection into the same.

[0091] The components of the invention described were sized to be installed in structures attached to an ROV 35, which may be structures at the bottom of the ROV 35 (FIG. 4a) or at the rear of the same (FIG. 4b).

[0092] Numerous variations falling under the scope of protection of this application are allowed. Accordingly, it reinforces the fact that the present invention is not limited to the particular configurations/embodiments described above.