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BR-112022006436-B1 - PRESSURE COMPENSATOR AND ASSEMBLY COMPRISING A SUBMARINE INSTALLATION AND SUCH PRESSURE COMPENSATOR

BR112022006436B1BR 112022006436 B1BR112022006436 B1BR 112022006436B1BR-112022006436-B1

Abstract

PRESSURE COMPENSATOR AND ASSEMBLY COMPRISING A SUBMARINE INSTALLATION AND SUCH PRESSURE COMPENSATOR. The invention proposes a double barrier pressure compensator to achieve pressure compensation between seawater surrounding a subsea installation and a medium filling a volume of the subsea installation. Said pressure compensator comprises: - a housing (20) with a first opening (202b) and a second opening (30); - a first bellows (4) and a second bellows (5) arranged one above the other within the housing (20) and each watertightly fixed to the housing (20) at its distal ends (43, 53); - movable separation element (6) adapted to move within the housing (20) and watertightly fixed to each of the proximal ends (44, 54) of the first and second bellows (4, 5), so as to separate a first compartment (21) from a second compartment (22) of the housing (20), sealing one from the other. The said pressure compensator (2) further comprising a third compartment (23) formed by a space between the housing (20) and the first and second bellows (4, 5), the first compartment (21) being arranged to be fluidly connected to the subsea installation (1) through the second opening (30), the second compartment (22) being arranged to be in communication with seawater through the first opening (202b), and (...).

Inventors

  • Stein Folkner

Assignees

  • TechnipFMC Norge AS

Dates

Publication Date
20260310
Application Date
20201001
Priority Date
20191002

Claims (15)

  1. 1. DOUBLE BARRIER PRESSURE COMPENSATOR FOR ACHIEVING PRESSURE COMPENSATION BETWEEN SEAWATER SURROUNDING A SUBMARINE INSTALLATION (1) AND A MEDIUM FILLING A VOLUME OF THE SUBMARINE INSTALLATION (1), characterized in that said pressure compensator (2) comprises: - a housing (20) having a first opening (202b) and a second opening (30); - a first bellows (4) and a second bellows (5) arranged one above the other within the housing (20); - a movable separation element (6) adapted to move within the housing (20), opposite locations of said movable separation element (6) being watertightly fixed to the proximal ends (44, 54) of the first and second bellows (4, 5), so as to separate a first compartment (21) from a second compartment (22) of the housing (20), each of the first bellows (4) and second bellows (5) having a distal end (43, 53) fixed in a watertight manner to the housing (20), and wherein said first compartment (21) and second compartment (22) are sealed from each other, said pressure compensator (2) further comprising a third compartment (23) formed by a space between the housing (20) and the first and second bellows (4, 5), wherein the first compartment (21) is arranged to be fluidly connected to the subsea installation (1) through the second opening (30), the second compartment (22) being arranged to be in communication with seawater through the first opening (202b), and said third compartment (23) being filled with a barrier medium.
  2. 2. PRESSURE COMPENSATOR, according to claim 1, characterized in that the housing (20) comprises a cylinder extending between a first cross plate (203) and a second cross plate (204) of the housing (20), said first cross plate (203) being provided with said first opening (202b), and said second cross plate (204) being provided with said second opening (30).
  3. 3. PRESSURE COMPENSATOR, according to claim 1 or 2, characterized in that the movable separation element is a movable plate.
  4. 4. PRESSURE COMPENSATOR, according to any one of claims 1 to 3, characterized in that the first and second bellows (4, 5) have individual closed ends joined together to form the movable separation element (6).
  5. 5. PRESSURE COMPENSATOR, according to any one of claims 1 to 4, characterized in that the first and second bellows (4, 5) are welded, brazed and/or flanged in a leak-tight manner to the housing (20) and to the movable separating element (6) at their respective two ends (44, 54; 43, 53)).
  6. 6. PRESSURE COMPENSATOR, according to any one of claims 1 to 5, characterized by comprising a rod (7) fixed to the movable separation element (6) and projecting from the housing (20) through an orifice (202a) disposed therein, the rod (7) being designed to monitor the level of the medium inside the housing (20).
  7. 7. PRESSURE COMPENSATOR, according to claim 6, characterized in that said orifice (202a) is an axial orifice.
  8. 8. PRESSURE COMPENSATOR, according to claim 6 or 7, characterized by the orifice (202a) for the rod (7) being adapted to guide the movement of the rod (7) and, in this way, the rod (7) aligns and guides the movement of the movable separation element (6).
  9. 9. PRESSURE COMPENSATOR, according to any one of claims 1 to 8, characterized in that the movable separating element (6) comprises an extension configured to be in contact with an inner side face (201) of the housing (20) so as to help guide the movement of the movable separating element (6).
  10. 10. PRESSURE COMPENSATOR, according to any one of claims 1 to 9, characterized by comprising an elastic element (8) sandwiched between the housing (20) and the movable separation element (6) in the second compartment (22) which communicates with the first opening (202b) to preload the compensator.
  11. 11. PRESSURE COMPENSATOR, according to claim 10 and any of claims 6 to 9, characterized in that the elastic element is a spring (8) mounted on the rod (7).
  12. 12. PRESSURE COMPENSATOR, according to any one of claims 1 to 11, characterized by comprising a second pressure compensator (11) with a bellows or a bag, connected to the pressure compensator (2) to compensate for variations in the volume of the barrier medium in the third compartment (23).
  13. 13. PRESSURE COMPENSATOR, according to any one of claims 1 to 12, characterized in that the medium and/or the barrier medium is a dielectric fluid.
  14. 14. SUBMARINE ASSEMBLY characterized by comprising a submarine installation (1) and a pressure compensator (2) defined in any of the preceding claims and connected to the installation.
  15. 15. SUBMARINE ASSEMBLY, according to claim 14, characterized in that the housing (20) of the pressure compensator (2) is mounted in the subsea installation (1), the second opening (30) being common to the pressure compensator (2) and a tank (10) of the subsea installation (1).

Description

Field of Invention [0001] The present invention relates to a pressure compensator for a subsea installation. The invention also relates to an assembly comprising a subsea installation and such a pressure compensator. History of the Invention [0002] Subsea installations refer to assemblies used underwater. Such subsea installations may, in particular, include compressors, pumps, motors, transformers and any other electrically powered subsea equipment. [0003] Such subsea installations, for example, transformers, may be installed in water depths of 3,000 m or more, so that they are exposed to pressures of up to or even exceeding 300 bar. To protect these components from seawater and to cope with the high pressures prevailing in such a subsea environment, these components are fitted with subsea enclosures. To provide relatively compact and lightweight enclosures, pressure-compensated enclosures may be used. The pressure-compensated enclosure is generally filled with a medium, and the components operated within the pressure-compensated enclosure are designed to function under high pressures. For example, such installations are placed inside a tank that is filled with a medium, for example, a dielectric medium such as transformer oil, in order to protect the installations and ensure ideal working conditions. The tank is generally filled with the medium at 20°C and atmospheric pressure. Once the tank is full, the pressure inside the tank is substantially equal to normal atmospheric pressure. [0004] Variations in water temperature, hydrostatic pressure, and heat produced by the subsea installation during operation also result in variations in the volume of the medium within the subsea installation. Such volume variations can cause deterioration of the tank or equivalent containing the medium, as it is generally rigid. [0005] In this context, the use of pressure compensators is known. Document EP 2 169 690 discloses such a pressure compensator comprising two bellows arranged one inside the other, thus providing a double barrier separating the oil from the surrounding seawater. [0006] The configuration of the disclosed pressure compensator is such that there is always a need to compensate for volume variations within the space between the two bellows. [0007] Furthermore, even with a double barrier, such a compensator remains fragile, especially with regard to side impacts. [0008] The invention seeks to provide a dual barrier pressure compensator that is capable of resolving at least one of the aforementioned drawbacks. Summary of the Invention [0009] The invention proposes a double barrier pressure compensator to achieve pressure compensation between seawater surrounding a subsea installation and a medium filling a volume of the subsea installation. [0010] According to the invention, said pressure compensator comprises: - a housing having a first opening and a second opening; - a first bellows and a second bellows arranged one above the other within the housing; - a movable separation element adapted to move within the housing, opposite locations of said movable separation element being securely fixed to the proximal ends of the first and second bellows so as to separate a first compartment from a second compartment of the housing. [0011] Each of the first and second bellows has a distal end securely fixed to the housing. [0012] According to the invention, said first compartment and second compartment are sealed from each other. Said pressure compensator further comprises a third compartment formed by a space between the housing and the first and second bellows, where the first compartment is arranged to be fluidly connected to the subsea installation through the second opening, the second compartment is arranged to be in communication with seawater through the first opening, and said third compartment is filled with a barrier medium. [0013] Thanks to these aspects, the pressure compensator is compact, provides a double barrier for the first bellows by virtue of the housing and the airtight seal between the three compartments, does not require the use of an additional compensator for the third compartment in most situations, and provides lateral protection of the bellows thanks to the housing. [0014] In addition, such a pressure compensator avoids the risk of blockage that can occur with the multiplicity of rods in document EP 2 169 690. [0015] According to the advantageous aspects of the present invention, which can be combined: - the housing comprises a cylinder extending between a first cross plate and a second cross plate of the housing, said first cross plate being provided with said first opening and said second cross plate being provided with said second opening. - the movable separating element is a movable plate. - the first and second bellows have individual closed ends joined together to form the movable separating element. - The first and second bellows are welded, brazed, and/or flanged in a tight fit to