GB2164841A - Cleaning subsea surfaces - Google Patents

Cleaning subsea surfaces Download PDF

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Publication number
GB2164841A
GB2164841A GB08517343A GB8517343A GB2164841A GB 2164841 A GB2164841 A GB 2164841A GB 08517343 A GB08517343 A GB 08517343A GB 8517343 A GB8517343 A GB 8517343A GB 2164841 A GB2164841 A GB 2164841A
Authority
GB
United Kingdom
Prior art keywords
brush
scouring
subsea
cleaning
action
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08517343A
Other versions
GB8517343D0 (en
GB2164841B (en
Inventor
Tony James Sidney Green
Stephen Geoffrey Drake
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
OILFIELDS INSPECTION SERVICES
Original Assignee
OILFIELDS INSPECTION SERVICES
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by OILFIELDS INSPECTION SERVICES filed Critical OILFIELDS INSPECTION SERVICES
Publication of GB8517343D0 publication Critical patent/GB8517343D0/en
Priority to GB8605927A priority Critical patent/GB2174105B/en
Publication of GB2164841A publication Critical patent/GB2164841A/en
Application granted granted Critical
Publication of GB2164841B publication Critical patent/GB2164841B/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B59/00—Hull protection specially adapted for vessels; Cleaning devices specially adapted for vessels
    • B63B59/06—Cleaning devices for hulls
    • B63B59/08—Cleaning devices for hulls of underwater surfaces while afloat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B6/00—Cleaning by electrostatic means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C3/00—Abrasive blasting machines or devices; Plants
    • B24C3/02—Abrasive blasting machines or devices; Plants characterised by the arrangement of the component assemblies with respect to each other
    • B24C3/06—Abrasive blasting machines or devices; Plants characterised by the arrangement of the component assemblies with respect to each other movable; portable

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Cleaning In General (AREA)

Abstract

A method of cleaning a subsea surface of an electrically-conductive object e.g. the hull 10 of a vessel comprises scouring the surface e.g. by means of rotary brush 11 while simultaneously applying a D.C. voltage between scourer and surface to assist in removing material from the surface, the D.C. voltage being such that material is removed from the surface by electrolytic action and/or by spark action. The brush may be vibrated or an abrasive disc may be used instead. Alternatively, a jet of negatively charged electrolyte, which may or may not contain abrasive particles, may be used to clean the surface instead of brush or disc. <IMAGE>

Description

SPECIFICATION Cleaning subsea surfaces
Description: This invention is concerned with a method and apparatus for cleaning subsea surfaces.
It is known to machine workpieces by electrochemical machining. In electrochemical machining, a liquid electrolyte, e.g. sea water, may be passed between the surface of a metal workpiece and a tool electrode while a D.C. voltage is applied across electrolyte in the gap between tool and workpiece so that metal is removed from the workpiece.
It is an object of the present invention to provide an improved method and apparatus for cleaning subsea surfaces.
According to the invention, a method for cleaning a subsea surface of an electricallyconductive object comprises subjecting the surface to the action of scouring means while simultaneously applied a D.C. voltage between the scouring means and the surface to assist in removing material from the surface, the D.C. voltage being such that material is removed from the surface by electrolytic action and/or by spark action.
The invention also provides apparatus for cleaning a subsea surface of an electricallyconductive object, which apparatus comprises scouring means for acting on said surface, and means for applying an electric potential difference between the scouring device and the surface to assist in removing material from the surface.
The scouring means may comprise a brush or a member (e.g. a disc) with an abrasive or other uneven working surface and means for rotating or vibrating the brush or member or otherwise causing it to move over and exert a scouring action on the subsea surface.
In one form of the invention, the scouring means comprises a brush with bristles of steel wire or other electrically conductive material or a member with electrically conductive projections providing an abrasive or other uneven working surface, and spark cleaning action is caused when bristles or projections leave or approach the surface being cleaned. The spark action may or may not be accompanied by some electrolytic cleaning action.
Alternatively, the scouring means may comprise means for projecting a jet of negatively charged electrolyte (e.g. sea water) on to said subsea surface. Means may be provided for injecting abrasive material into said jet.
Means are preferably provided for scanning the scouring means over the subsea surface.
If desired, more than one scouring means may be provided.
The following is a description, by way of example, of embodiments of the invention, reference being made to the accompanying schematic drawing.
The drawing shows an electrically-conductive workpiece 10 in the form of the hull of a vessel or other subsea structure. A brush 11 with electrically-conductive bristles is traversed over the surface of the workpiece to clean it.
The bristles of the brush contact the surface and extend substantially parallel to and are disposed around an axis normal to the surface. The brush is rotated on said axis by a suitable motor (e.g. a water motor). Electric current is supplied from the surface by a supply rail 12 to a subsea power supply unit 13 which may typically have a pulsed D.C. output of 200 amps and 12v. The positive output terminal of the power supply unit is connected to the workpiece and the negative output terminal is connected to the brush. Thereby, cleaning of the surface by the scouring action of the brush is assisted by electrolytic action and/or spark action of the kind which occurs in electrochemical machining. The brush may be air irrigated and work in an enclosure, primarily to reduce drag. In use, the brush is scanned over the surface of the structure.
Instead of being rotated, the brush may be mounted to vibrate.
If desired, a disc with an abrasive or similar uneven surface may be used instead of a brush.
In another embodiment, the brush or disc may be replaced or supplemented by a jet of negatively charged electrolyte which is scanned over the surface of the structure.
Abrasive material in particulate form may be injected into the jet to aid surface cleaning and the removal of non-metallic debris.
CLAIMS 1. A method for cleaning a subsea surface of an electrically-conductive object comprising subjecting the surface the action of scouring means while simultaneously applying a D.C.
voltage between the scouring means and the surface to assist in removing material from the surface, the D.C. voltage being such that material is removed from the surface by electrolytic action and/or by spark action.
2. A method according to claim 1 in which the scouring means comprises a brush or a member with an abrasive or other uneven working surface, which brush or member is moved over said subsea surface.
3. A method according to claim 1 in which the scouring means is a jet of negatively charged electrolyte.
4. A method according to claim 3 in which abrasive material is injected into said jet.
5. A method according to any preceding claim in which the scouring means is scanned over said subsea surface.
6. Apparatus for cleaning a subsea surface of an electrically-conductive object comprising scouring means for acting on said surface, and means for applying an electric potential difference between the scouring device and
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Cleaning subsea surfaces Description: This invention is concerned with a method and apparatus for cleaning subsea surfaces. It is known to machine workpieces by electrochemical machining. In electrochemical machining, a liquid electrolyte, e.g. sea water, may be passed between the surface of a metal workpiece and a tool electrode while a D.C. voltage is applied across electrolyte in the gap between tool and workpiece so that metal is removed from the workpiece. It is an object of the present invention to provide an improved method and apparatus for cleaning subsea surfaces. According to the invention, a method for cleaning a subsea surface of an electricallyconductive object comprises subjecting the surface to the action of scouring means while simultaneously applied a D.C. voltage between the scouring means and the surface to assist in removing material from the surface, the D.C. voltage being such that material is removed from the surface by electrolytic action and/or by spark action. The invention also provides apparatus for cleaning a subsea surface of an electricallyconductive object, which apparatus comprises scouring means for acting on said surface, and means for applying an electric potential difference between the scouring device and the surface to assist in removing material from the surface. The scouring means may comprise a brush or a member (e.g. a disc) with an abrasive or other uneven working surface and means for rotating or vibrating the brush or member or otherwise causing it to move over and exert a scouring action on the subsea surface. In one form of the invention, the scouring means comprises a brush with bristles of steel wire or other electrically conductive material or a member with electrically conductive projections providing an abrasive or other uneven working surface, and spark cleaning action is caused when bristles or projections leave or approach the surface being cleaned. The spark action may or may not be accompanied by some electrolytic cleaning action. Alternatively, the scouring means may comprise means for projecting a jet of negatively charged electrolyte (e.g. sea water) on to said subsea surface. Means may be provided for injecting abrasive material into said jet. Means are preferably provided for scanning the scouring means over the subsea surface. If desired, more than one scouring means may be provided. The following is a description, by way of example, of embodiments of the invention, reference being made to the accompanying schematic drawing. The drawing shows an electrically-conductive workpiece 10 in the form of the hull of a vessel or other subsea structure. A brush 11 with electrically-conductive bristles is traversed over the surface of the workpiece to clean it. The bristles of the brush contact the surface and extend substantially parallel to and are disposed around an axis normal to the surface. The brush is rotated on said axis by a suitable motor (e.g. a water motor). Electric current is supplied from the surface by a supply rail 12 to a subsea power supply unit 13 which may typically have a pulsed D.C. output of 200 amps and 12v. The positive output terminal of the power supply unit is connected to the workpiece and the negative output terminal is connected to the brush. Thereby, cleaning of the surface by the scouring action of the brush is assisted by electrolytic action and/or spark action of the kind which occurs in electrochemical machining. The brush may be air irrigated and work in an enclosure, primarily to reduce drag. In use, the brush is scanned over the surface of the structure. Instead of being rotated, the brush may be mounted to vibrate. If desired, a disc with an abrasive or similar uneven surface may be used instead of a brush. In another embodiment, the brush or disc may be replaced or supplemented by a jet of negatively charged electrolyte which is scanned over the surface of the structure. Abrasive material in particulate form may be injected into the jet to aid surface cleaning and the removal of non-metallic debris. CLAIMS
1. A method for cleaning a subsea surface of an electrically-conductive object comprising subjecting the surface the action of scouring means while simultaneously applying a D.C.
voltage between the scouring means and the surface to assist in removing material from the surface, the D.C. voltage being such that material is removed from the surface by electrolytic action and/or by spark action.
2. A method according to claim 1 in which the scouring means comprises a brush or a member with an abrasive or other uneven working surface, which brush or member is moved over said subsea surface.
3. A method according to claim 1 in which the scouring means is a jet of negatively charged electrolyte.
4. A method according to claim 3 in which abrasive material is injected into said jet.
5. A method according to any preceding claim in which the scouring means is scanned over said subsea surface.
6. Apparatus for cleaning a subsea surface of an electrically-conductive object comprising scouring means for acting on said surface, and means for applying an electric potential difference between the scouring device and
the surface to assist in removing material from the surface.
7. Apparatus according to claim 6 in which the scouring means comprises a brush or a member with an abrasive or other uneven working surface and means for moving said brush or member over said subsea surface.
8. Apparatus according to claim 6 in which the scouring means comprises a brush with bristles of steel wire or other electrically conductive material or a member with electrically conductive projections providing an abrasive or other uneven working surface, and spark cleaning action is caused when bristles or projections leave or approach the surface being cleaned.
9. Apparatus according to claim 6 in which the scouring means comprises means for projecting a jet of negatively charged electrolyte on to said subsea surface.
10. Apparatus according to claim 8 in which said scouring device includes means for injecting abrasive material into said jet.
11. Apparatus according to any of claims 6 to 10 in which scanning means are provided for scanning said scouring means over said subsea surface.
12. A method for cleaning a subsea surface substantially as hereinbefore described with reference to the accompanying drawing.
13. Apparatus for cleaning a subsea surface substantially as hereinbefore described with reference to the accompanying drawing.
GB08517343A 1984-07-11 1985-07-09 Cleaning subsea surfaces Expired GB2164841B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8605927A GB2174105B (en) 1985-03-11 1986-03-11 Cleaning subsea surfaces

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB848417656A GB8417656D0 (en) 1984-07-11 1984-07-11 Cleaning subsea surfaces

Publications (3)

Publication Number Publication Date
GB8517343D0 GB8517343D0 (en) 1985-08-14
GB2164841A true GB2164841A (en) 1986-04-03
GB2164841B GB2164841B (en) 1988-02-17

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
GB848417656A Pending GB8417656D0 (en) 1984-07-11 1984-07-11 Cleaning subsea surfaces
GB08517343A Expired GB2164841B (en) 1984-07-11 1985-07-09 Cleaning subsea surfaces

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB848417656A Pending GB8417656D0 (en) 1984-07-11 1984-07-11 Cleaning subsea surfaces

Country Status (1)

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GB (2) GB8417656D0 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2174105A (en) * 1985-03-11 1986-10-29 Oilfield Inspection Services Cleaning subsea surfaces
WO2000068070A1 (en) * 1999-05-07 2000-11-16 Dennis Mason Method and apparatus for removing marine organisms from a submerged substrate

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WO 85/02869 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2174105A (en) * 1985-03-11 1986-10-29 Oilfield Inspection Services Cleaning subsea surfaces
GB2174105B (en) * 1985-03-11 1989-06-21 Oilfield Inspection Services Cleaning subsea surfaces
WO2000068070A1 (en) * 1999-05-07 2000-11-16 Dennis Mason Method and apparatus for removing marine organisms from a submerged substrate

Also Published As

Publication number Publication date
GB8517343D0 (en) 1985-08-14
GB8417656D0 (en) 1984-08-15
GB2164841B (en) 1988-02-17

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PCNP Patent ceased through non-payment of renewal fee