US3766742A

US3766742A - Submarine tethered working unit and method of manipulating

Info

Publication number: US3766742A
Application number: US00216037A
Authority: US
Inventors: M Smith; A Brun
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1972-01-07
Filing date: 1972-01-07
Publication date: 1973-10-23
Anticipated expiration: 1990-10-23
Also published as: GB1363798A; FR2167731B1; FR2167731A1; JPS4874002A; SE404054B; NL7217314A; CA965249A

Abstract

A submarine tethered working unit is lowered into proximity with an underwater apparatus requiring servicing. The working unit is then maneuvered under its own power into embracing guided relationship with the pylon of the apparatus and the unit then crawls upwardly on the pylon under its own power and locks itself rigidly to the pylon in a position near a removable module of the underwater apparatus. The working unit separates the module from the remainder of the apparatus and carries it to the surface of the water after separation from the pylon.

Description

1 1 Oct. 23, 1973 United States Patent Smith et a1.

SUBM ARINE TETHERED WORKING UNIT AND METHOD OF MANIPULATING 3,550,388 12/1970 Smith et 61/69 R Primary ExaminerJ. Karl Bell Md.; Andre George Brun, Paris, France ABSTRACT [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

Jan. 7, 1972 [22] Filed A submarine tethered working unit is lowered into proximity with an underwater apparatus requiring ser- Appl. No.: 216,037

vicing. The working unit is then maneuvered under its own power into embracing guided relationship with the pylon of the apparatus and the unit then crawls [52] US. 61/69 R, 114/16, 166/.5

upwardly on the pylon under its own power and locks itself rigidly to the pylon in a position near a removable module of the underwater apparatus. The work- 166/5 ing unit separates the module from the remainder of [56] References Cited the apparatus and carries it to the surface of the water after separation from the pylon. UNlTED STATES PATENTS I 3,163,221 12/1964 166/.6 15 Claims, 11 Drawing Figures PATENIEDHU 23 um v sum 1 (IF 4 FIGI f SUBMARINE TETHEREI) WORKING UNIT AND METHOD OF MANIPULATING BACKGROUND OF THE INVENTION Underwater manipulators and working units for use in servicing subsea oil well equipment and the like are known in the prior art, including entirely self-propelled submarine working units and units which are tethered from the surface of the water. Some examples of the prior art are contained in 11.8. Pat. Nos. 3,166,123; 3,381,485; and 3,550,388.

The need for the present invention arises from the requirement for a working unit which may be precisely positioned relative to underwater apparatus and more particularly relative to certain components of the apparatus which are removable. In order to constitute an improvement on the prior art, the working unit must possess in addition to the above ability to position itself precisely the additional ability to lock itself securely to the underwater apparatus in a primary working position so that the working unit will be able to exert sufficiently powerful forces on the apparatus to fulfill its mission.

These and other objectives of the invention will become apparent during the course of the following detailed description.

SUMMARY OF THE INVENTION The present invention isdirected to a submersible working unit to be utilized in'connection with underwater apparatus requiring periodic servicing. The submersible working unit features the ability to maneuver itself into engagement with a pylon body at the bottom of a body of water and to embrace, of clasp the pylon in such a manner that the working unit may be guided therealong. Following this, the working unit climbs or crawls under its own power toward the top of the pylon and locks itself firmly to the pylon in a primary working position, such as adjacent to a removable module of the underwater apparatus. -While in such position, the working unit may perform the required servicing of the apparatus and may separate and lift the removable module, transferring the same bodily to the working unit.-Following this, the-unit disengages the pylon and carries the apparatus module to the surface or to some other required transferpoint.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 10 is a plan view of a submersible working unit.

in accordance with a modification of the invention; and

FIG. 1 l is a similar plan view showing another modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing figures in detail and particularly to FIGS. 1 through 3, there is shown a submersible working unit having a box-like frame 20 within which may be mounted removably a diving bell or sphere 22 for service personnel or observers. The diving bell 22 is centered and cradled in the frame 20 by a circular array of elements 24 consisting of utility gas bottles, buoyancy elements and cushions.

At its lower end and forward corners, the frame. 20 carries rigid forwardly projecting arm structures 26, each of which is bifurcated as shown at 28 for the reception of power-operated engaging and positioning arms 30 which are pivotally attached to the rigid arm structures 26 through trunnions 32. The arms 30 are preferably somewhat curved longitudinally as best shown in FIG. 3 to enable them to clasp or embrace a cylindrical pylon 34 forming the subsea anchorage and support of apparatus requiring servicing by the unit 20. Such subsea apparatus will be referred to in greater detail as the description proceeds. The engaging and positioning arms 30 are pivoted horizontally about the axes of their trunnions 32 by power operators 36 in the form of a pair of extensible and retractable cylinder-piston units. The units 36 have their cylinder ends pivotally secured at 38 to the interior sides of rigid arm structures 26' and have their piston rod ends pivotally connected as indicated at 40'to the rear ends of the arms 30 in rearwardly spaced relation to the trunnions 32. It may be noted in FIGS. 2 and 3 that the engaging and positioning arms 30 are swingable between closed or active positions where these arms embrace the pylon 34 and open or inactive positions where the arms 30 are divergent. These two positions are shown in full lines and broken lines in FIG. 3.

Rota'tably mounted on the forward end of each arm 30 is a climbing and guiding wheel 42 forthe working unit having conventional power driving means, not shown. The wheels 42 have, a covering of suitable friction material on their peripheries to resist. slipping while under power and in contact with the pylon 34. Additional friction rollers 44 which may be powered-or unpowered are journaled on the top and bottom por-' tions of the rigid arm structures 26 so as to engage the rearward side of the pylon 34 in upper andlower pairs. The driving means, not shown,for the wheels 42 and rollers 4:4 may be of a conventional nature and may be located in the center area 46 at the forward side of the frame 26 between the upper and lower sets of rollers 44, FIG.; 2. when the arms 30are in the active pylonembracing positions, FIG. 3, the wheels 42 are disposed well forwardly'of the center verticalaxis of the-pylon and the rollers 44. are well rearwardly of this-axis.

Therefore, the working unit through its arm structure is embracing the vertical pylon at four approximately equidistantly spaced points around the circumference of the pylon. This very secure engagement of the work ing unit to the pylon enables the working unit to climb or crawl upwardly on the pylon with precision and stability. When the arms 30 are expanded to their open divergent positions shown in broken lines in FIG. 3, these arms are then generally aligned with the axes of the diverge'nt rollers 44, and together therewith are cabable of guiding or funneling the working unit' smoothly into contact with the vertical pylon, as when the unit initially engages the pylon after being lowered into the water. The rollers 44 are also adapted toform somewhat resilient bumpers for cushioning the engagement of the working unit with the rigid pylon.

Referring particularly to FIGS. 2 and 3, means is provided on the mobile working unit to lock the same rigidly to the pylon 34 in a primary working position adjacent to a removable module 48 of the subsea apparatus requiring servicing. As shown, the removable module 48 is normally atop the pylon 34 which is fixed to the sea bottom by known techniques. The locking means for the working unit comprises a vertically spaced pair of power-operated locking shoes 50 on the central portion of the frame 20 between the pairs of rollers 44. These shoes are thrust forwardly into firm contact with the rear side of the pylon 34 by conventional power actuator means, not shown, also contained on the frame 20. The shoes 50 are retracted from the pylon during the climbing movement of the working unit thereon and at all other times except when the unit is to be locked fixedly in the primary working position, for ex ample, as shown in FIGS. 1 and 6. Similar poweroperated extendable and retractable locking shoes 52 are located on the interior sides of the arms 30 near the centers of these arms. The shoes 52 are powered by conventional means, not shown. Preferably, the

shoes

50 and 52 are operated substantially in synchronism. The arrangement is such, FIG. 3, that when the working unit is locked in position on the pylon 34 the sets of

shoes

50 and 52 are engaging the pylon at three widely spaced circumferential locations. With the shoes 50 lying on the center line of the pylon, the other shoes 52 are positioned somewhat beyond a plane through the axis of the pylon so that it will not be possible for the working unit to be dislodged laterally of the pylon axis when in the locked position.

For maneuvering and propelling the submersible working unit in the water, as when approaching one side of the pylon 34, FIG. 4, while tethered from above, a pair of opposite side conventional propulsion units 52 are provided on the frame 20 near the tops of the arm structures 26 and near the center of the frame 20 as viewed from above, FIG. 3. Additionally, the frame 20 which constitutes the body of the working unit possesses other features such as side racks 54 for various portable tools and guide rollers 56 to facilitate mating with certain types of deep diving craft. Still additional utility features, not shown in the drawings, may be included in the working unit.

At its top, the box-like frame 20 carries a pair of upstanding triangular rigid side extensions 58 to the tops of which is. pivoted a vertically swingable module manipulating frame 60. The opposite side members of the frame 60 are pivoted near their lower ends to the extensions 58 as shown at 62. Below this point, depending crank arms 64 on the frame 60 are pivotally connected as at 66 with power operators 68 in the form of extensible and retractable cylinder-piston units. These units are additionally attached pivotally at 70 to the frame 20 near the upper forward comers thereof. The power operators 68 may thus swing the frame 60 from a vertical position shown in full lines in FIG. 1 to a near horizontal working position shown in broken lines.

The manipulating frame 60 is provided at its top with a pivoted crosshead 72, turned on its pivot by another cylinder-piston unit 74 carried by the frame 60. A coupling head 76 for engaging and lifting the module 48 is provided on the frame 60 coupled with the crosshead 72 by flexible fluid supply hoses 78 through which certain servicing fluids can be delivered to the subsea apparatus from above through a hose 8G and a swivel coupling 82 on the crosshead 72. The coupling 76 along with the crosshead 72 is pivoted to the top of the frame 60 through a cross shaft 84. Also on the crosshead 72 an annular-type ram or jack 86 for raising and lowering the coupling 76 is provided and various portable tools can be passed through the center bore of this annular device so as to enter the interior of the subsea apparatus when the coupling 76 is in communication therewith as indicated in broken lines in FIG. 1.

In addition to pumping certain servicing liquids into the subsea apparatus and performing other known types of service operations, the pivoting frame 60 with the coupling 76 is utilized to bodily lift the module 48 from the top of the pylon 34 and to place the module at rest on a suitable seat 88 forming a part of the frame 20, after which the module may be transported to the surface of the water with the entire working unit. It should be clear that the frame 60 and associated components is operated in a similar but reverse manner to replace the module 48 on the top of the subsea apparatus or to install a new module.

The working unit can be tethered to a surface support vessel by the hose 80, which may be of the high tensile strength type. If preferred, the tethering may be done through a cable or a cable in addition to the hose. Electrical power may be supplied to the working unit through a suitable electrical cable, not shown. In cases where the working unit is not buoyant, the tethering hose or cable will support the weight of the unit, and in such a case a constant tension hoisting system is preferably employed on the surface. .1

OPERATION The method of utilizing and manipulating the abovedescribed working unit in connection with the required servicing of the underwater apparatus is as follows, referring particularly to FIGS. 4 through 9 of the drawings. In FIG. 4, the tethered working unit has been lowered to the approximate level of the middle of the pylon 34 and is spaced laterally from the pylon. Since the pylon is cylindrical and the working unit is self-guiding into engagement with the pylon, it may approach from any direction. The working unit will be subject to up and down movements of the surface vessel as caused'by sea conditions. No significant horizontal movements from above will be transmitted to the working unit.

Referring to FIG. 5, the working unit by usingits propulsion devices 52', whether propellers, jets or the like, now maneuvers itself horizontally toward the pylon 34 and can approach the same from any direction, asstated. The widely divergent arms 30 and rollers44 will I serve to gently guide the working unit into proper engagement with the fixed pylon .during theapproach, and the rollers 44 serve as buffers to cushion the contact.

When the working unit is at a maximum vertical position under influence of surface waves (zero vertical velocity), the arms 30 are closed around the pylon to their positions shown in full lines in FIG. 3'and also shown in FIG. 5. The driving means for the climbing

rollers

42 or 44, or both, is set into operation and the climbing mechanism creates a positive link between the unit and pylon and the unit now begins to propel itself upwardly along the pylon toward the primary working position shown in FIG. 6. During this period, the constant tension hoisting system on the surface ship will further absorb oscillations caused by wave action. The

tether 80 is now slacked off, FIG. 6, and the working unit is completely independent of the surface and continues its vertical climb on the pylon until it stops with precision at the predetermined working level. At this point, the locking

shoes

50 and 52 are activated and shift into locking engagement with the pylon and the working unit now is rigidly held on the pylon and stabilized for the performance of its various work functions under the most favorable conditions.

Proceeding to FIG. 7, the manipulating frame 60 is now activated to bring the coupling 76 into coupled engagement with the module 48 for the delivery of servicing fluids to the subsea apparatus through the

hoses

80 and 78, and so that other known types of servicing may be carried out. At the proper time, FIG. 8, the removable module 48 is bodily lifted from the top of the pylon 34 by raising the manipulating frame 60 back to the vertical. When this has been completed, the ram 86 is utilized to lower the module 48 onto its seat 88, FIG.

2, and the module is now safely stabilized at the top and,

at the bottom by the coupling 76 and the seat 88.

At this time, referring to FIG. 9, the locking

shoes

50 and 52 are retracted and the arms 30 are separated to release the pylon 34 and the working unit may back away somewhat from the pylon using its propulsion means 52' and may then be elevated to the surface with the module 48 thereon by utilizing the tether 80 and associated hoisting means.

' The invention permits particularly effective use of a tethered working unit, which unit has the advantage of being clear of the sea bottom at all times so that the propellers and other moving parts will not stir up sediment, thereby allowing the working unit to operate in clear water with good visibility for personnel in the bell or sphere 22. In some cases, however, the attaching,

vergent bumpers 110 which serve to guide the unit 104 smoothly into engagement with the pylon 34. The unit 104 has pivotally mounted on the arm structures 108 a pair of diametrically opposed vertically extending crawler mechanisms 112 to securely lock the working climbing and locking features of the invention may be applied to non-tethered submarine-type units. The greatest virtue of the invention lies in the ability of the working unit to reliably and securely locate and attach itself on'the pylon 34 and to climb up the pylon with precision and to stop thereon at a precise level, followed by secure locking which enables the unit to perform all interventions with reliability and efficiency.

Referring now to FIG. 10, a slightly modified form of working unit 90 is shown having a body portion or frame 92 adapted to receive and support the module 48 and a diving bell, such as the bell 22 in FIG. 2. The unit 90 has rigid diverging arm structures 94 on the forward 7 side thereof and pivoted power-operated engaging and positioning arms 96 corresponding to the arms 30 and being actuated by power means 98. The arms 96 at their leading ends carry pylon-engaging rollers 100 which may be unpowered guide rollers. In lieu of the diverging crawler rollers 44 of the prior embodiment, the working unit 90 is equipped with a vertically extending power-operated caterpillar-type crawler mechanism 102 which engages the adjacent side of the pylon 34, with the rollers 100 situated forwardly of the axial center of the pylon. A suitable positive locking means 102' similar to the shoes and 52 is also included in the unit 90. The general method above-described and illustrated in FIGS. 4 through 9 remains essentially unchanged in connection with the working unit 90.

FIG. 11 depicts a further modification in which a 6 working unit 104 having a body or frame 106 possesses diverging rigid arm structures 108 at its forward side. Associated with the arm structures 108 are forward diunit in the desired precise position on the pylon 34. Again, the method as described in connection with FIGS. 4 through 9 is essentially unchanged and a further description thereof is thought to be unnecessary for a full understanding of the invention.

While the present embodiments have been disclosed with certain degree of particularity, it should be observed that the present disclosure has been made by way of example only. It is not desired therefore that the invention be limited specifically to the disclosed embodiments but it is to be understood that all equivalents, alterations and modifications within the spirit and scope of the present invention are herein meant to be included.

We claim:

I. A method of servicing an underwater apparatus having a body portion secured to the bottom of a body of water, comprising the steps of:

maneuvering a submersible working unit in the water and thereby causing the working unit to engage said body portion of the apparatus; mechanically coupling the working unit movably to said body portion at an elevation below the top of thebody portion; and moving the working unit upwardly on the body portion under its own power by frictionally driving the working unit along the surface of the body portion, and then stopping and fixedly locking the working unit near the top of the body portion for the performance of servicing operations on the apparatus.

2. The method as defined by claim 1, and said mechanical coupling of the working unit to said body portion comprising coupling by embracing the body portion with movable arm means.

3. The method as defined in claim 2, and said moving of the working unit upwardly on the body portion consisting of frictionally driving the embracing arm means upwardly along the surface of the body portion.

- 4. The method as defined by claim 1, and the, additional step of separating a removable module from the top of the body portion by means of the working unit while the working unit is fixedly locked to the body portion; and t 1 transferring said module onto the working unit for transporting to a delivery location.

5. Apparatus for 'servicing'an underwater apparatus having a body portion secured to the bottom of a body of water comprising:

a submersible unit maneuverable in the water relative to the body portion of said apparatus; propulsion means on said unit to move the unit'toward one side of said body portion;

engaging arms extending from said unit and closing about said body portion in an embracing mode when said unit moves into engagement with the body portion;

power drive means on the unit frictionally engaging the exterior surface of the body portion and positively propelling the unit upwardly over the exterior surface to an apparatus servicing position on the body portion;

and additional power means on said unit engaging the body portion to lock the unit fixedly thereto in said apparatus servicing position.

6. The invention as defined by claim 5, and a mechanical manipulator means on said unit capable of performing servicing operations while the unit is in said servicing position.

7. The invention as defined by claim 5, and said engaging arms including at least a pair of divergent arms pivotally secured to one side of said unit; and

power operating means for said arms causing them to close about said body portion after the divergent arms have guided the unit into properly centered engagement with the body portion.

8. The invention as defined by claim 7, and roller means on said engaging arms having direct contact with the exterior surface of said body portion.

9. The invention as defined by claim 5, and said power drive means on the unit comprising power driven roller means having frictional contact with the exterior surface of the body portion when said arms are closed about the body portion in said embracing mode.

10. The invention as defined by claim 9, and said power drive means including at least one crawler type traction device on said unit frictionally engaging the exterior surface of said body portion when said engaging arms are closed about the body portion.

11. The invention as defined by claim 5, and wherein said additional power means to lock the unit fixedly to the body portion comprises plural power-operated locking shoes movable substantially radially of the body portion into rigid clamping engagement therewith at widely spaced points around the circumference of the body portion, the body portion comprising a substantially cylindrical pylon.

12. The invention as defined by claim 5, and said submersible unit having a frame body portion; and

a diving bell mounted removably within the frame body portion.

13. The invention as defined by claim 6, and said mechanical manipulator means comprising a pivoted frame on the top of said unit; and

the latter to be moved relative to said frame.

i i II! II

Claims

1. A method of servicing an underwater apparatus having a body portion secured to the bottom of a body of water, comprising the steps of: maneuvering a submersible working unit in the water and thereby causing the working unit to engage said body portion of the apparatus; mechanically coupling the working unit movably to said body portion at an elevation below the top of the body portion; and moving the working unit upwardly on the body portion under its own power by frictionally driving the working unit along the surface of the body portion, and then stopping and fixedly locking the working unit near the top of the body portion for the performance of servicing operations on the apparatus.

4. The method as defined by claim 1, and the additional step of separating a removable module from the top of the body portion by means of the working unit while the working unit is fixedly locked to the body portion; and transferring said module onto the working unit for transporting to a delivery location.

5. Apparatus for servicing an underwater apparatus having a body portion secured to the bottom of a body of water comprising: a submersible unit maneuverable in the water relative to the body portion of said apparatus; propulsion means on said unit to move the unit toward one side of said body portion; engaging arms extending from said unit and closing about said body portion in an embracing mode when said unit moves into engagement with the body portion; power drive means on the unit frictionally engaging the exterior surface of the body portion and positively propelling the unit upwardly over the exterior surface to an apparatus servicing position on the body portion; and additional power means on said unit engaging the body portion to lock the unit fixedly thereto in said apparatus servicing position.

7. The invention as defined by claim 5, and said engaging arms including at least a pair of divergent arms pivotally secured to one side of said unit; and power operating means for said arms causing them to close about said body portion after the divergent arms have guided the unit into properly centered engagement with the body portion.

12. The invention as defined by claim 5, and said submersible unit having a frame body portion; and a diving bell mounted removably within the frame body portion.

13. The invention as defined by claim 6, and said mechanical manipulator means comprising a pivoted frame on the top of said unit; and a power operator connected with said frame to swing it between generally horizontal and generally vertical positions.

14. The invention as defined by claim 13, and a coupling head pivotally mounted upon said frame and adapted for attachment to a removable module on the underwater apparatus, whereby said module may be Lifted and transferred onto said unit.

15. The invention as defined by claim 14, and a power actuator for said pivoted coupling head allowing the latter to be moved relative to said frame.