Passive heave compensator

Patent metadata

Field	Value
Publication number	US-2016002012-A1
Application number	US-201414766230-A
Country	US
Kind code	A1
Filing date	Feb 5, 2014
Priority date	Feb 7, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A passive heave compensator comprising: a main hydraulic cylinder, including a moveable piston having a piston rod extendible through the main hydraulic cylinder and a piston head, a gas phase above the piston head, and at least one oil phase below the piston head separated by a boundary; an upper connection point associated with the main hydraulic cylinder and a lower connection point associated with the piston rod; and at least one accumulator, the or each accumulator having a moveable separator to divide the accumulator between a gas phase above the separator, and an oil phase below the separator, and the or each oil phase being in communication with an oil phase in the main hydraulic cylinder; characterized in that the main hydraulic cylinder further comprises a cylinder sleeve co-axial with the piston head to provide, in co-ordination with the piston head, the boundary between the gas phase and the at least one oil phase in the main hydraulic cylinder. In this way, the variation in the coordination between the shape, longitudinal position, or both of the piston head, which naturally must be smaller in cross-section than the cross-section of the main hydraulic cylinder, and the transverse extent of the cylinder sleeve, provides variation in the cross-sectional area of oil volume in the main hydraulic cylinder, and thus different damping effects along the length of the main hydraulic cylinder, which are available to the user.

First claim

1 . A passive heave compensator comprising:
a main hydraulic cylinder, including a moveable piston having a piston rod extendible through the main hydraulic cylinder and a piston head, a gas phase above the piston head, and at least one oil phase below the piston head separated by a boundary; an upper connection point associated with the main hydraulic cylinder and a lower connection point associated with the piston rod; and at least one accumulator, the or each accumulator having a moveable separator to divide the accumulator between a gas phase above the separator, and an oil phase below the separator, and the or each oil phase being in communication with an oil phase in the main hydraulic cylinder; wherein the main hydraulic cylinder further comprises a cylinder sleeve co-axial with the piston head to provide, in co-ordination with the piston head, the boundary between the gas phase and the at least one oil phase in the main hydraulic cylinder.

2 . A passive heave compensator as claimed in claim 1 wherein the cylinder sleeve is moveable.

3 . A passive heave compensator as claimed in claim 2 wherein the cylinder sleeve is at least in part moveable in line with movement of the piston head.

4 . A passive heave compensator as claimed in claim 1 , wherein the main hydraulic cylinder has a first oil phase below the piston head and a second oil phase below the cylinder sleeve.

5 . A passive heave compensator as claimed in claim 4 wherein the first and second oil phases are in fluid communication.

6 . A passive heave compensator as claimed in claim 4 where in the first and second oil phases are separate.

7 . A passive heave compensator as claimed in claim 4 , wherein each oil phase in the main hydraulic cylinder is in fluid communication with a separate accumulator.

8 . A passive heave compensator as claimed in claim 7 wherein each accumulator provides a different compensation to the main hydraulic cylinder.

9 . A passive heave compensator as claimed in claim 1 , wherein the piston head and cylinder sleeve provide multi-step compensation to the compensator.

10 . A passive heave compensator as claimed in claim 1 , wherein the cylinder sleeve has transverse longitudinal side walls forming an inner cylinder for the piston head.

11 . A passive heave compensator as claimed in claim 1 , wherein the piston head and cylinder sleeve have different displacements within the main hydraulic cylinder.

12 . A passive heave compensator as claimed in claim 1 having the cylinder sleeve with depending transverse longitudinal side walls forming an inner cylinder for the piston head, to provide a first oil phase below the piston head and a second oil phase defined by the cylinder sleeve side walls and inner wall of the main hydraulic cylinder.

13 . A passive heave compensator as claimed in claim 1 , having the cylinder sleeve with upstanding transverse longitudinal side walls forming an upstanding inner cylinder for the piston head, and a first oil phase below the piston head and above the cylinder sleeve in fluid communication with the first accumulator, and a second oil phase below the cylinder sleeve and in fluid communication either with the same accumulator as the first oil phase, or optionally with a separate accumulator.

14 . A passive heave compensator as claimed in claim 1 , having the cylinder sleeve with upstanding transverse longitudinal side walls forming an upstanding inner cylinder for the piston head, and a single oil phase below the piston head and cylinder sleeve in fluid communication with a single accumulator.

15 . A passive heave compensator comprising:
a main hydraulic cylinder, including a moveable piston having a piston rod extendible through the main hydraulic cylinder and a piston head, a gas phase above the piston head, and at least one oil phase below the piston head separated by a boundary; an upper connection point associated with the main hydraulic cylinder and a lower connection point associated with the piston rod; and at least one accumulator, the or each accumulator having a moveable separator to divide the accumulator between a gas phase above the separator, and an oil phase below the separator, and the or each oil phase being in communication with an oil phase in the main hydraulic cylinder; wherein the cross-section of the boundary changes depending upon the position of the piston head along the length of the main hydraulic cylinder.

16 . A passive heave compensator as claimed in claim 15 wherein the main hydraulic cylinder further comprises a cylinder sleeve co-axial with the piston head wherein the piston head provides a first oil phase having a first cross-sectional area, and the cylinder sleeve provides a second oil phase having a second cross-sectional area.

17 . A passive heave compensator as claimed in claim 16 wherein the coordination of the cylinder sleeve and the piston head provides a third oil phase with a third cross-sectional area.

18 . A passive heave compensator as claimed in claim 15 , wherein each oil phase is in fluid communication with a separate accumulator.

19 . A method of providing variable compensation to a passive heave compensator as defined in claim 1 , comprising the steps of:
(a) providing loading to the passive heave compensator through the lower connection point; (b) displacing oil in at least one oil phase from the main hydraulic cylinder to at least one accumulator by displacement of at least one of the cylinder sleeve, piston head, or both.

Assignees

• Technip France

Inventors

• Cannell David
• Labbe Christophe
• Odigie Eric
• Riddell Shaun

Classifications

• F16F9/065

  Expansion chamber provided on the upper or lower end of a damper, separately there from or laterally on the damper · CPC title

• E21B19/006

  including heave compensators · CPC title

• B66C23/53 Primary

  including counterweight or means to compensate for list, trim, or skew of the vessel or platform (counterweights or supports for balancing lifting couples B66C23/72; equipment to decrease unwanted vessel movements B63B39/00) · CPC title

• B63B39/03 Primary

  by transferring liquids · CPC title

• B66C13/06

  for minimising or preventing longitudinal or transverse swinging of loads · CPC title