US3590870A

US3590870A - Loading arm

Info

Publication number: US3590870A
Authority: US
Inventors: Albert A Ashton
Original assignee: YOUNGSTOWN SHEET AHD TUBE CO
Current assignee: Oil States Industries Inc
Priority date: 1969-11-26
Filing date: 1969-11-26
Publication date: 1971-07-06
Anticipated expiration: 1988-07-06
Also published as: FR2072405A5; JPS508805B1; CA923785A; GB1323444A

Abstract

This patent discloses a loading arm in which packing in the swivel joints at the upper end of the riser pipe and at the innermost end of the inner arm may be readily and easily changed or serviced without disassembly of either swivel joint.

Description

I United States Patent 1 1 3,590,870

[72] Inventor Albert A. Ashton [56] References Cited D ll UNITED STATES PATENTS P 969 3,013,343 1/1963 Howell 1 1 1 1 i4l/387 E 5"? d 3' 3,085,593 4/1963 Sorensen l37/6l s an en 3,239,249 3 I966 A ht .i 285 152 [73) Assignee Youngstown Sheet and Tube Company 3 34 9' 3x9) 85y v i r v i H 371615 3,434,497 3/1969 Bily 137/61 5 Primary Examiner-Laverne D. Geiger Assistant Examiner-William H. Wright Attorneys-J. Vincent Martin, Joe E. Edwards, M. H. Gay,

Alfred H1 Evans and Jack R. Springgate [54] LOADING ARM SCI-nus nnwhgnss ABSTRACT: This patent discloses a loading arm in which [52] U.S. Ci [37/615 packing in the swivel joints at the upper end of the riser pipe [51 Int. Cl 867d 5/06 and at the innermost end of the inner arm may be readily and Field 0| fl l 7/ l5; easily changed or serviced without disassembly of either l4l/387; 248/280; 285/l52, IBI, 272

swiveljointr I 1 32 L 43 I 1 26 l 37 JR? v 24 i 23 2 25 A? u '9 1.

PATENTEUJuL sum SHEET 3 BF 5 lllhv n A w mm w w Mm w AW A EM m LOADING ARM This invention relates to loading arms.

In the recent years the trend in design of loading arms for transferring fluids between vessels and a shore station has been to the use of articulating rigid pipes. See the patents to Mowell U.S. Pat. No. 3,073,343 and Sorensen US. Pat. No. 3,085,598. These arms have become larger and larger in diameter and it is presently necessary to utilize heavy lifting equipment to support the inboard and outboard arm when it is desired to change the swivel joint packing at the inner end of the inboard arm and at the upper end of the riser pipe.

My US. Pat. No. 3,239,249 and the recent Bily U.S. Pat. No. 3,434,49l have suggested methods of servicing swivel joints at the inner end of the inboard arm. No previous way is known to service the swivel joint at the upper end of the riser pipe without utilizing heavy equipment to support the inner and outer arms while disassembling the swivel joint to replace the packing therein.

This invention provides a loading arm in which the packing at the swivel joint on top of the riser pipe and the packing at the inner end of the inboard arm may be readily serviced or replaced without disturbing the swivel joints; that is, during replacement of packing, the inner and outer anns of the loading arm are supported upon the riser pipe.

It is an object of this invention to provide a loading arm in which the packing in the swivel joint at the top of the riser pipe and the swivel joint at the inner end of the inboard arm may be changed without disassembly of either swivel joint, and while the inner and outer arms are supported upon the riser pipe.

Another object is to provide a loading arm having dual inboard arms which are supported on aligned-swivels at the inboard end of the arms in which the packing for these inboard swivels and the packing in the swivel on top of the riser pipe may be readily serviced or changed while the inner and outer arms are supported from the riser pipe through the swivel joints being serviced.

Another object is to provide a loading arm in which the packing in the swivel joint associated with the riser pipe, and the swivel joint at the inboard end of the inner arm may be changed by removing a single flow conductor member which extends between the riser pipe and the inboard arm.

Another object is to provide a special spacer to associate with the removable member as in the preceding object to facilitate ready removal of the member and servicing of the packing.

Other objects, features and advantages of this invention will be apparent from the drawings, the specifications and the claims.

In the drawing wherein like reference numerals indicate like parts, and wherein illustrative embodiments of this invention are shown;

FIG. I is a view in elevation of a loading arm constructed in accordance with this invention with a portion of the inboard am and the entire outboard arm omitted;

FIG. 2 is a view in vertical cross section through the upper end of the riser pipe and the inner end of the inboard arm;

FIG. 3 is a isometric of the structural member to which one bearing race of each swivel joint shown in FIG. 2 is attached and showing a portion of the structural member in dashed outline;

FIG. 4 is a view similar to FIG. 2 with the parts shown in exploded position;

FIG. 5 is an enlarged fragmentary section through the structure illustrating the swivel joint packing and the spacer between the packing and the removable elbow;

FIG. 6 is a side elevational view of a large-diameter loading arm utilizing two inboard arms;

FIG. 7 is a fragmentary elevational view of the inboard and outboard arms of the structure shown in FIG. 6 and a small portion of the riser pipe with all of the counterbalancing mechanism omitted;

FIG. 8 is a cross'sectional view through the upper end of the riser pipe and the inner ends of the inboard arms of the loading arm shown in FIGS. 6 and 7-,

FIG. 9 is an isometric view with parts shown in dashed lines of the structure member securing the swivel joints at the inner end of the inboard arms to the swivel joint at the top of the riser pipe;

FIG. I0 is a plan view of the structure shown in FIG. 8', and

FIG. 11 is a elevational view of the structure shown in FIG. 8.

Referring first to FIGS. 1 through 5, there is illustrated a form of this invention which utilizes a single inner arm. Abase 10 supports a riser pipe ll. At the upper end of the riser pipe a first swivel joint, indicated generally at I2, is provided to permit rotation of the remainder of the loading arm on the riser pipe about a vertical axis. In order to directly support the remainder of the loading arm from the swivel joint l2, a structural member indicated generally at I3 is supported on the swivel joint 12.

In order to provide for rotation of the inner arm 14 of the loading arm about a horizontal axis, it is supported on the structural member 13 by a second swivel joint indicated generally at I5. Fluid is conducted between the

swivel joints

12 and 15 through an elbow 16. The outer arm and its swivel connection with the inner arm 14 are not shown in these figures. The remainder of the inner arm and outer arm will be comparable to the arms shown in Sorensen US. Pat. No. 3,085,593.

The inner arm 14 carries a counterbalance support 17 on which the counterbalance I8 is rotatably mounted. A fine trim counterbalance is provided by the trim weights 19. For a full disclosure of the manner in which the counterbalance l8 counterbalances the weight of the inner and outboard arms of the loading arm, reference is made to the above-identified Sorensen patent.

The first swivel joint 12 has a first bearing race 2! which is nonrotatably secured to the upper end of the riser pipe 11 by any suitable means such as a ring of bolts, one of which is shown at 22. The swivel joint 12 has a second bearing race 23 which is rotatably supported on the riser 11 by a plurality of bearings. 24.

The structural member 13 is secured to the second bearing race 23 and is supported thereon by a plurality of bolts, one of which is shown at 25.

The structural member 13 includes an angle plate 26,

stiffening plates

27 and 28 secured to the side edges of the angle plate 26 as by welding, and reinforcing

members

29 and 30 at the extremities of the right-angle plate 26.

The structural member 13 has a ring of bolt holes 31 through which the bolts 25 extend to secure the horizontal run of the right-angle plate 26 to the second bearing race of swivel 12.

The second swivel joint 15 has a first bearing race 32, which is nonrotatably secured to the right-angle plate 26 by a plurality of bolts 33 which extend through a ring of holes 34 in the right-angle plate.

A plurality of bearings 35 in the second swivel joint I5 support a second bearing race 36 for rotation about a horizontal axis. The inner arm 14 of the loading arm is secured to the second bearing race as by a ring of bolts, one of which is shown at 37.

The structure thus described supports the inner arm 14 for rotation about the vertical axis of the first swivel joint 12 and for rotation about the horizontal axis of swivel joint 15, thus the second bearing race 36 of the second swivel joint 15 rotates in a plane which is normal to the plane of rotation of the second bearing race 23 of the first swivel joint 12.

To provide for fluid flow port 38 is provided in the horizontal leg of the member 26 in alignment with flowway 39 through the first swivel joint 12. A second port 41 is provided in the vertical leg of the right angle member 26 in alignment with the flowway 42 through the second swivel joint 15. The elbow 16 provides a removable flow conductor which communicates with

ports

38 and 41 to conduct flow therebetween. The elbow 16 is provided at its opposite ends with

suitable flanges

43 and 44 which are secured thereto in any desired manner, as by welding. The flange 43 is secured to the rightangle plate 26 by a plurality of bolts 45. The flange 44 is likewise secured to the right-angle member 26 by a ring of bolts which is shown at 46.

When the ring of

bolts

45 and 46 are removed, the elbow l6 may be moved laterally to the left of the drawings as viewed in FIG. 2 or vertically of the drawing as viewed in FIG. 2 to expose the packing assembly in the two swivel joints. In other words, there is a 90 arc in the right-angle plate 26 which permits the elbow 16 to be removed from the structural member as indicated in the exploded view FIG. 4.

Removable packing is provided in each of the swivel joints l2 and to prevent flow of fluid between the bearing races of each swivel joint. This packing is accessible for servicing or replacement without disassembly of the swivel joints upon removal of the flow conductor of elbow 16, as illustrated in FIG. 4.

It will be noted that each of the ports 38 and 4] in structural member I3 is of a slightly greater diameter than the inner diameter of the flowways 39 and 42 and the flowway in elbow 16. This enlarged diameter provides an access space for reaching the removable packing. Referring in particular to FIG. 5, the removable packing is provided by a U-shaped ring, preferably of Teflon, 47. The legs of the ring 47 are expanded by a spring 48.

In order to fill the space provided by the enlarged port 38 and provide a continuous flow passageway between the swivel joint passageway 39 and the elbow 16, a spacer 49 is provided in the port 38. The inner diameter of the spacer is substantially the same as the inner diameter of the swivel joint passageway 39. The spacer 49 has a lower plane surface Sl which engages the removable packing 47 and provides a sealing surface therewith. A plurality of holes shown in dashed outline at 52 are provided in which tools may be engaged to lift the spacer from the port 38.

In order to hold the spacer firmly in engagement with the upper end of the second race 23, resilient means are provided for urging the spacer downwardly into engagement with the bearing race. Preferably this resilient means is a flexible arm 490, which is an integral part of die spacer. 49. when in relaxed condition the arm 49a is at an angle relative to the bottom surface SI of the spacer. When the flange 43 is secured to the structural member I3, the arm 49a is flexed downwardly and held under tension to insure that the spacer remains seated on the bearing race 23. To seal between the spacer and flange 43 an O'ring 53 is preferably provided in the radially outer extremity of the arm 49a. The arm 49a has a slightly greater outer diameter than the main body portion of spacer 49 to fit within the counterbore 54 at the upper end of port 38. This prevents the spacer 49 from being inserted upside down and insures that in assembly the lower face 51 will be properly positioned for engagement by the removable seal 47.

When it is desired to service or change a packing, the rings of

bolts

45 and 46 are removed and the elbow l6 lifted to an out-of-the-way position as illustrated in FIG. 4. A suitable tool is inserted in the holes 52 provided in spacer 49 and the spacer 49 lifted from port 38. The seal 47 may then be removed and replaced. The parts are reassembled in the reverse order. It will be apparent from a study of FIG. 4 and the description of the assembly hereinabove that during replacement or servicing of the seal the swivel joints are not disturbed, and the inner and outboard arms are fully supported on the riser pipe. Thus, it is not necessary to employ a heavy lifting equipment capable of supporting the weight of the inboard and outboard anns while swivel joints are disassembled as in prior practice to ser vice these swivel joints packing. While the above description has been related to the servicing of the swivel joint packing immediately above the riser pipe II, it is apparent that when the elbow I6 is removed the swivel joint packing of swivel joint 15 may also be serviced if desired by removing the identi cal spacer ring 49 to gain access to the identical packing 47.

Reference is now made to FIGS. 6 through II which illustrate a form of this invention utilizing a double inner arm. The base 61 supports a riser pipe 62. At the upper end of the riser pipe, a first swivel joint 63 provides for rotation about a vertical axis. Through a suitable structural member indicated generally at 64, a plurality of trunnion swivel joints, such as shown at 65 and 66, are supported directly from the riser pipe swivel joint 63. Inner arms extend from each of the trunnion swivel joints. In the form illustrated, inner arm 67 extends from second swivel joint 65, and inner arm 68 extends from third swivel joint 66. The swivel joints 65 and 66 are spaced from each other in parallel relationship and rotate about a common axis in planes which are normal to the plane of rotation of the swivel joint 63.

The double inner arm carries a single outer arm 69 through a suitable Y-type swivel connection indicated generally at H. The first swivel joint 63 has a first bearing race 72 which is nonrotatably secured to the upper end of the riser pipe 62. The bearing race 72, through suitable bearings 73, rotatably supports a second bearing race 74. It will be noted that the bearing race 72 necks down to a small diameter relative to the size of the riser pipe. The diameter through the bearing race 72 at its smallest dimension provides a flow area approximately equal to the combined flow area of the two inner arms. A larger diameter riser pipe and first swivel joint 63 are utilized for strength in supporting the weight of the remainder of the loading arm.

A structural member indicated generally at 64 is carried by the rotatable bearing race 74 and provides a direct support for the inner and

outer arms

67, 68, and 69. FIG. 9 shows the structural member to be generally boxlike in form with an open top. A baseplate 76 at the bottom of the structural member is provided with a plurality of boltholes 77 through which a plurality of bolts 78 extend to secure the structural member to the rotatable bearing race 74. A port 78 is provided in the baseplate which aligns with the flowway 79 through the swivel joint and is slightly larger than the flowway 79 to receive the removable seal 8] and the spacer 82 in the same manner as in the form illustrated in FIGS. I through 5.

The structural member is provided with parallel spaced

end plates

83 and 84. These plates have a plurality of boltholes 85 through which bolts 86 extend to secure the second and third swivel joints 65 and 66 to the structural member. A port 87 is provided in end plate 83, and a like port 88 is provided in end plate 84. These ports are slightly larger than the flowways 89 and 91 through the swivel joints 65 and 66, respectively, so as to receive the packing spacer 82 in the manner hereinbefore explained.

In the single inboard arm form of this invention, an L- shaped plate 26 secured the riser swivel joint with a trunnion swivel joint. In this form of the invention, a member corresponding to an essentially U-shaped plate made up of the baseplate and the two end plates serves the same function and supports second and third swivel joints 65 and 66 on the first swivel joint 63. Sideplates 92 and 93 extend between the baseplate and the two end plates on opposite sides to complete a boxlike structure with an open top.

The second swivel joint 65 has a first bearing race 94 which is secured to the structural member by bolts 86. A second bearing race 95 is supported by bearings 96 for rotation in a plane normal to the plane of rotation of the second bearing race 74 of the first swivel 63. The inner arm 67 is secured to the rotatable bearing race 95.

In like manner, the third swivel joint 66 has a first bearing race 97 which is secured to the structural member by the bolts 86. This bearing race supports a rotatable bearing race 98 through bearings 99. The two rotatable bearing races 95 and 98 of the second and third swivels rotate in spaced parallel planes which are nonnal to the plane of rotation of the second bearing race 74 of the first swivel joint. The bearing races 95 and 98 rotate about a common axis which is perpendicular to the axis of rotation of the bearing race 74 of the first swivel joint. Thus, through the structural member the inner and outer arms of the loading arm are supported on the riser pipe through the structural member.

The removable packing II and the spacer 82 are identical to the corresponding packing and spacer shown in FIG. 5.

A removable flow conductor means indicated generally at llll provides for flow of fluid between the riser pipe 62 and the two

inner arms

67 and 68. The flow conductor has an annular flange 102 at its lower end which is connected to the structural member by bolts I03. A central bore [04 is provided through the flange section 102, preferably of equal diameter with the inner diameter of the first swivel joint bearing race 72. The flow conductor has an outlet 105 which communicates with the second swivel joint 65, and a second outlet 106 which communicates with the third swivel joint 66. Preferably, a divider 107 extends down through the flow conductor to divide the flow into two streams. This is particularly useful when fluid is flowing from the riser pipe into the inboard arm. The curved upper ends I08 and 109 of the flow conductor thus may readily turn the fluid into the inner arms.

Preferably, the removable flow conductor 10! is collapsible along the axis of the second and third swivel joints 65 and 66 to provide clearance between the flow conductor 10] and the

end plates

83 and 84 of the structural member adjacent the ports 87 and 88 in the structural member. This clearance permits the flow conductor to be easily removed through the open top of the structural member. Preferably, each end of the flow conductor 10] surrounding the

ports

105 and 106 is slightly retractable or collapsible to provide clearance. Such clearance may be provided by a telescoping joint between the outer telescoping sleeve 1 l0 and the inner telescoping sleeve III which surround the outlet I06. A suitable seal I12 seals between the members 110 and Ill. The members may telescope relative to each other for a short distance when the bolts 1 13 are removed. A like telescoping arrangement is provided about the flowway 105 in the removable flow conductor by providing the inner telescoping member 114 within the outer telescoping sleeve 115 with a sliding seal 116 therebetween. When the bolts 113 are removed, the member 114 may be retracted slightly to provide clearance with the end plate 83.

In the use of the double inner arm form of invention, the bolts 103 and l [3 are removed, the telescoping members 111 and .114 forced back into the flow conductor 10! a slight distance, and the flow conductor 10] lifted vertically out through the open top of the structure member. It will be appreciated that by providing two telescoping collapsible sections, the flow conductor may be readily removed even though one collapsible section cannot be collapsed as the flow conductor is free to shift laterally within the structural member once all of the bolts I03 and 113 are removed.

Once the flow conductor 10] is removed, the several spacers 82 may be removed to provide access to the packing 81 without disassembly of the three swivel joints. The inner and

outer arms

67, 68, and 69 will be supported from the first swivel joint on top of the riser pipe during the time that the packing is being serviced, and there is no necessity for providing heavy lifting equipment to support the inboard and outboard arms during change of packing.

As these loading arms may have inboard and outboard arms on the order of 100 feet in total length, and an outboard arm diameter of 24 inches, it will be appreciated that the weight of the arms plus the counterweight assembly indicated generally at 117 is very substantial. This invention avoids the need for massive equipment to support the arms during a change of packing. This is particularly important where the loading arms are on offshore docks and the lifting equipment must be brought along side by means of barges.

It will be appreciated that the particular packing and the packing spacer arrangement illustrated are preferred, but other packing arrangements which might or might not employ a spacer of the type illustrated might be used.

While a telescoping joint is provided for collapsing the flow conductor, any other collapsible type structure might be substituted.

While a structure, such as shown in FIGS. 6 through 11, is preferred for a double inner arm structure, it is apparent that a double-elbow structure might be utilized. An adapter plate of the same size would be substituted for annular flange 102. The adapter plate would have a pair of ports therein. Elbow-type flow conductors would extend from each port to the second and third swivel joints 65 and 66, respectively, in the manner taught in FIGS. 1 through S.

It will be appreciated that instead of the collapsing or telescoping structural member, a member having internal wedge-shaped confronting end wall surfaces diverging upwardly might be utilized. A flow conductor having opposite facing end surfaces of matching taper would provide for ease of removal of the structural member. The spacers with resilient arms would reduce the tolerance problem with such a structure. The telescoping structure is preferred as tolerance problems are held to a minimum.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.

What I claim is:

1. A loading arm comprising,

a riser pipe.

a first swivel joint at one end of the riser pipe having a first bearing race nonrotatably secured to the riser pipe and a second bearing race rotatable relative thereto,

a structural member secured to the second bearing race for supporting the remainder of the loading am,

said structural member having a first port in alignment with the flowway through the first swivel joint,

at least one additional swivel joint having a first bearing race nonrotatably secured to said structural member and a second bearing race rotatable relative thereto in a plane normal to the plane of rotation of the second bearing race of said first swivel joint,

an inner arm secured to the second bearing race of each additional swivel joint,

said structural member having a port in alignment with the flowway through each additional swivel joint,

removable flow conductor means releasably secured to said structural member between said first port and each said port in alignment with each said additional swivel joint,

and removable packing preventing flow of fluid between the bearing races of each swivel joint said removable packing being accessible for replacement without disassembly of said swivel joints when said removable flow conductor is removed.

2. The loading arm of claim 1 wherein said flow conductor means holds and said packing in operating position.

3. The loading arm of claim 1 wherein each port through the structural member is greater in diameter than the inner diameter of the removable flow conductor immediately adjacent each port to provide an access space,

a spacer is removably positioned in each access space and is held therein by said removable flow conductor,

and said removable packing is accessible upon removal of said removable flow conductor and spacers.

4. The loading arm of claim 3 wherein said spacers provide seal surfaces engaged by said packing and said spacers have a resilient member which bears against said removable flow conductor and cooperates with stop means to properly position the seal engaging surface of said spacers in contact with said packing.

5. A leading arm comprising a riser pipe,

a structural member secured to the second bearing race for supporting the remainder of the loading arm,

a second swivel joint having a first bearing race nonrotatably secured to said structural member and a second bearing race rotatable relative thereto in a plane normal to the plane of rotation of the second bearing race of said first swivel joint,

an inner ann secured to the second bearing race of said second swivel joint,

said structural member having a second port in alignment with the flowway through said second swivel joint,

removable flow conductor means releasably secured to said structural member between said first and second ports,

and removable packing preventing flow of fluid between the bearing races of each swivel joint,

said removable packing being accessible for replacement without disassembiy of said swivel joints when said removable flow conductor is removed.

6. The loading arm of claim wherein said flow conductor means holds said packing in operating 7. The loading arm of claim 5 wherein each port through the structural member is greater in diameter than the inner diameter of the removable flow conductor immediately adjacent each port to provide an access space,

and said removable packing is acceuible upon removal of said removable flow conductor and spacers.

8. The loading arm of claim 5 wherein said spacers provide seal surfaces engaged by said packing and said spacers have a resilient member which bears against said removable flow conductor and cooperates with stop means to properly position the seal engaging surface of said spacers in contact with said packing.

9. The loading arm of claim 5 wherein said removable flow conductor means is a 90 elbow.

It). A loading arm comprising,

a riser pipe,

said structural member having a first port means in alignment with the flowway through the first swivel joint,

second and third swivel joints each having first bearing races secured to said structural member and supporting second bearing races in spaced parallel relationship for rotation about a common axis in planes normal to the plane of rotation of the second bearing race of said first swivel joint,

inner arms secured to said second bearing races of said second and third swivel joints,

said structural member having a second port in alignment with said second swivel joint and a third port in alignment with said third swivel joint,

removable flow conductor means releasably secured to said structural member between said first port means and each of said second and third ports,

said removable packing being accessible for replacement without disassembly of said swivel joints when said removable flow conductor is removed.

II. The loading arm of claim 10 wherein said flow conductor means holds said packing in operating position.

12. The loading arm of claim 10 wherein each port and port means through the structural member is greater in diameter than the inner diameter of the removable flow conductor immediately adjacent each port to provide an access space,

13. The loading arm of claim 10 wherein said spacers provide seal surfaces engaged by said packing and said spacers have a resilient member which bears against said removable flow conductor and cooperates with stop means to properly position the seal engaging surface of said spacers in contact with said packing.

l4. The loading arm of claim 10 wherein said removable flow conductor is collapsible along the axis of said second and third swivel joints to provide clearance between the removable flow conductor and said structural member adjacent the second and third ports.

[5. The loading arm of claim 10 wherein said removable flow conductor is provided with at least one telescoping section adjacent one of said second and third ports to provide clearance between the removable flow conductor and said structural member adjacent the second and third ports to provide clearance between the removable flow conductor and said structural member adjacent the second and third ports.

Claims

1. A loading arm comprising, a riser pipe, a first swivel joint at one end of the riser pipe having a first bearing race nonrotatably secured to the riser pipe and a second bearing race rotatable relative thereto, a structural member secured to the second bearing race for supporting the remainder of the loading arm, said structural member having a first port in alignment with the flowway through the first swivel joint, at least one additional swivel joint having a first bearing race nonrotatably secured to said structural member and a second bearing race rotatable relative thereto in a plane normal to the plane of rotation of the second bearing race of said first swivel joint, an inner arm secured to the second bearing race of each additional swivel joint, said structural member having a port in alignment with the flowway through each additional swivel joint, removable flow conductor means releasably secured to said structural member between said first port and each said poRt in alignment with each said additional swivel joint, and removable packing preventing flow of fluid between the bearing races of each swivel joint said removable packing being accessible for replacement without disassembly of said swivel joints when said removable flow conductor is removed.

3. The loading arm of claim 1 wherein each port through the structural member is greater in diameter than the inner diameter of the removable flow conductor immediately adjacent each port to provide an access space, a spacer is removably positioned in each access space and is held therein by said removable flow conductor, and said removable packing is accessible upon removal of said removable flow conductor and spacers.

5. A loading arm comprising a riser pipe, a first swivel joint at one end of the riser pipe having a first bearing race nonrotatably secured to the riser pipe and a second bearing race rotatable relative thereto, a structural member secured to the second bearing race for supporting the remainder of the loading arm, said structural member having a first port in alignment with the flowway through the first swivel joint, a second swivel joint having a first bearing race nonrotatably secured to said structural member and a second bearing race rotatable relative thereto in a plane normal to the plane of rotation of the second bearing race of said first swivel joint, an inner arm secured to the second bearing race of said second swivel joint, said structural member having a second port in alignment with the flowway through said second swivel joint, removable flow conductor means releasably secured to said structural member between said first and second ports, and removable packing preventing flow of fluid between the bearing races of each swivel joint, said removable packing being accessible for replacement without disassembly of said swivel joints when said removable flow conductor is removed.

6. The loading arm of claim 5 wherein said flow conductor means holds said packing in operating position.

7. The loading arm of claim 5 wherein each port through the structural member is greater in diameter than the inner diameter of the removable flow conductor immediately adjacent each port to provide an access space, a spacer is removably positioned in each access space and is held therein by said removable flow conductor, and said removable packing is accessible upon removal of said removable flow conductor and spacers.

9. The loading arm of claim 5 wherein said removable flow conductor means is a 90* elbow.

10. A loading arm comprising, a riser pipe, a first swivel joint at one end of the riser pipe having a first bearing race nonrotatably secured to the riser pipe and a second bearing race rotatable relative thereto, a structural member secured to the second bearing race for supporting the remainder of the loading arm, said structural member having a first port means in alignment with the flowway through the first swivel joint, second and third swivel joints each having first bearing races secured to said structural member and supporting second bearing races in spaced parallel relationship for rotation about a common axis in planes normal to the plane of rotation of the second bearing race of said first swivel joint, inner arms secured to said second bearing races of said second and third swivel joints, said structural member having a second port in alignment with said second swivel joint and a third port in alignment with said third swivel joint, removable flow conductor means releasably secured to said structural member between said first port means and each of said second and third ports, and removable packing preventing flow of fluid between the bearing races of each swivel joint, said removable packing being accessible for replacement without disassembly of said swivel joints when said removable flow conductor is removed.

11. The loading arm of claim 10 wherein said flow conductor means holds said packing in operating position.

12. The loading arm of claim 10 wherein each port and port means through the structural member is greater in diameter than the inner diameter of the removable flow conductor immediately adjacent each port to provide an access space, a spacer is removably positioned in each access space and is held therein by said removable flow conductor, and said removable packing is accessible upon removal of said removable flow conductor and spacers.

14. The loading arm of claim 10 wherein said removable flow conductor is collapsible along the axis of said second and third swivel joints to provide clearance between the removable flow conductor and said structural member adjacent the second and third ports.

15. The loading arm of claim 10 wherein said removable flow conductor is provided with at least one telescoping section adjacent one of said second and third ports to provide clearance between the removable flow conductor and said structural member adjacent the second and third ports to provide clearance between the removable flow conductor and said structural member adjacent the second and third ports.