US1852796A - Method of laying underwater pipe and apparatus therefor - Google Patents

Description

Ap ril'5, 1932. R. F. BENNETT 1,352,796

METHOD OF LAYING UNDERWATER PIPE AND APPARATUS THEREFOR Filed Sept. 21, 1929 2 Sheets--Sheet 1 I I F 'j- I l I 2 x k I a I? N N 1 i I hi N I 1 L I a f E 7 I Q ii- .i F6 I I I I.- I l I I V Inventor I llaymalltilfleauefi I I I j I Arm -1, A pril 5, 1932. R F. BENNE'YI'T 1,852,796

METHOD OF LAYING UNDERWATER PIPE AND APPARATUS THEREFOR F'iled Sept. 21, 1929 2 Sheets-Sheet /\5; W W I 5 T bar/0102701- flqylnoudfi'flezuzefl I 2 W I a] I Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE RAYMOND F. BENNETT, 0F PORTLAND, MAINE Application filed September 21, 1929. Serial No. 394,327.

My present invention relates to the laying of pipes or mains under water and particularly to such carefully ointed pipes as are intended for continuous mains for water supply or the like. 7

Such pipes or mains are usually laid in a trench dredged at sea bottom and frequently at considerable depth. The great problem is to getthe pipe sections carefully jointed together above water and deliver them at the bottom as a continuous main with certain flexibility without over-straining any of the joints.

It has been customary heretofore to assemble the pipe sections on a lighter'or scow and to slide the pipe so connected down an in-- clined chute from the lighter, but this has involved much diificulty on account of the movements of the lighter and chute on account of the waves and the variations of depth due to tides, and changes in elevation of the bottom, and on account of changes in slope of the bottom.

Furthermore, wherethe pipe is to be laid in a trench much difficulty has been experienced in holding alinement with it and it is of course important that the pipe be laid accurately as well as steadily. 1

My invention contemplates a difieren basis of operation, first, in that it isolates the assembly and delivery from a floating to a fixed support. Secondly, it conceives of a bottom level basis not only for pipe delivery but for trench digging. In the third place, it gains a basis of accuracy heretofore impossible at different depths and varying tides.

As illustrative of my invention I have shown in the accompanying drawings of apparatus and by diagram an installation characteristic of the problem and of individual importance in detail.

In the drawings, in which like reference characters are employed to indicate the parts discussed in the specification,

Fig. l is a somewhat diagrammatic side elevation of equipment in operation.

Fig. 2 is a diagrammatic plan view.

Fig. 3 is an end elevation, and

Fig. 4 is a detail of the pipe laying. As indicated in the drawings, the problem involved is that of assembling the pipe sec tions of a continuous main and usually in laying such sections in a trench indicated generally at T.

In accordance with my invention the-operation may he carried on in a substantially continuous manner, the trench being dug by any suitable dredging apparatus as indicated at D, and the pipe being assembled on a movable laying apparatus supported on the bottom and preferably spanning the trench alopg which it is progressed as the pipe is laic.

While such apparatus is capable of various structural embodiments, I have shown and will describe a simple and inexpensive equipment which I have found well adapted to meet difficult conditions and which well illustrates means for carrying out my concept of operation in accordance with my invention.

As shown in the drawings I preferably provide a pair of spaced bottom supports or shoes S. These are set at such distance apart as to span the trench and afford a stable base for the super-structure on which the pipe sec tions are to be assembled and from which they are to be laid as a continuous main. The bottom members or runners S which in the form shown are double timbers support front risers 4 and rear risers 5. The front risers are cross braced as at 6 and 7 and the rear risers similarly cross timbered as at 9 and 10. The side pairs 4 and 5 are braced diagonally as at 8. Centrally of this structure and rearwardly thereof I extend a brace 12 sloped downwardly to below the level of the bottom members S. This constitutesa support for the chute 1 down which the assembled pipe sections are delivered after assembly. The chute 1 comprises a curved section 1 which is curved on the arc of a circle on-a radiusjust sulficient to give the pipe the proper degree of fiexation after assembly. It is important that the pipe be thus initially flexed after assembly in order that there may be suflicient freedom in the joint to allow the main to accommodate itself to the bottom. At its upper end the chute 1 is disposed as tangent to this curved section and constitutes the assemreasonable regularity of depth.

bly area of the chute. This tangential section, if space is limited, or if it is desired to make the apparatus assmall as possible, may be depressed at its upper end from the point of tangency into a position parallel to a chord of the curved portion extending from this point of tangency one pipes length. I provide platform members 18-18 disposed on each side of this tangential portion of the chute and these platform members are cleated so as to provide a convenient assembly station for the men engaged in jointing up the pipe sections.

The chute 1 is supported adjacent its lower end by the chute brace 12 before described. I provide suitable braces as indicated at 14, 15, 16 and l7 so that the lower end of the chute which in practice extends a considerable distance beyond the tower section is steadily braced. This lower end is continued doWn to the intended bottom level of the trench in which the pipe is to be laid.v As heretofore suggested, one of the difliculties has been to dredge a trench under water with It has been difficult to gage the proper dredging depth on account of variation in the bottom and variations in tide. By providing gage markings G on the superstructure of the pipe laying apparatus, I am able on account of its bottom supported nature to provide for a very accurate dredging for the depth of trench regardless of the depth of water in which the dredging is being done. By observing the j gage markmgs the dredge operator is able to tell exactly how much allowance to make in order to provide the trench of the desired depth so that the lower end of the chute 1 will trail at the bottom of the trench and thus deliver the pipe with a minimum of dis-.

As the pipe P is coupled on the straight portion of the chute 1 I find it important to secure an initial fiexation of the joints as the pipe is slid down into the curved section of the chute. For this purpose I provide a flexible cable attached at 2 to one of the supports 5 adjacent its base, this being passed over the pipe in chute 1 and through a block 3 on the opposite side. The cable 2 is conveniently provided with a loop 2 which when the cable is not in use is simply hooked over some portion of the assembly station. When the pipe is being slid down the joints are flexed by putting tension on the cable, as for example, by hooking the whip of the lighter indicated at L on to the loop and thus obtaining power to draw the pipe sections firmly against the chute. The lighter L may be located in any convenient manner. As shown, it is laid alongside of the pipe assembly station so that pipe sections can be delivered as desired. When it is desired to lay a section of assembled pipes, the whole pipe delivery apparatus is slightly lifted or eased from the bottom by the lighter derrick and the lighter warped forward by its line H. This advances the chute along the trench and at the same time permits the assembled pipe sections to slide down the chute delivering those adjacent its lower end into the trench where they soon become covered by the natu- The operation before described provides for what is really a continuous operation even though it be carried out somewhat intermi tently. It is continuous in the sense that the dredging can be carried on as rapidly as pipe sections can be assembled and the laying apparatus moved ahead to follow the trench. Such a method is very economical and very efficient. The mains can be laid at any stage of the tide and in almost any weather, and without danger of breakage. The apparatus and equipment indicated may of course be varied and obviously any convenient type of lighter or dredge may be used.

What I therefore claim and desire to secure by Letters Patent is:

1. A device for theuse in laying sectional mains in a preformed underwater trench, comprising a pair of tower supports secured in lateral spaced relation to rest on the bed of the water body on either side of the trench, respectively, a tower structure built upon and rising from said supports, a chute supporting brace secured at its forward end to said tower structure and extending rearwardly therefrom beyond the rear ends of said tower supports and at a downward inclination to rest at its rear end on the trench bottom, a chute supporting framework erected on said brace, and a downwardly and rearwardly directed chute mounted at its forward end on said tower and at its rear end on said framework and said brace for guiding pipe sections assembled on the front upper end thereof downwardly and into the trench when the device is moved forward.

2. A device as set forth in claim 1 in which the chute is in the form of a trough straight at its upper end and curved intermediate its ends, an in which a roller is provided for cooperation wth the curved portion of the trough to cause adjacent pipe sections to be moved from a position in axial alineinent to an axially disalined position during their movement down said trough.

3., In a device as set forth in claim 1 in which the chute is curved intermediate its ends and means is provided for cooperation with the curved portion of the chute to cause adjacent sections of the pipe to be moved from a position in axial alinement to an axially disalined position during their movement down said chute.

4. A device for use in laying sectional mains under water, comprislng a pair of tower supports secured in lateral spaced relation to rest on the bed of the water body on either side of the line of work, respectively, a tower structure built upon and rising from said supports, a chute supporting brace secured at its forward end to said tower structure and extending rearwardly therefrom beyond the rear ends of said tower supports and at a downward inclination to rest at its rear end on said bed, a chute supporting framework erected on said brace, and a downwardly and rearwardly directed chute mounted at its forward end on said tower and at its rear end on said framework and said brace for guiding the pipe sections as sembled on the front upper end thereof downwardly and into line when the device is moved forward.

In testimony whereof I aflix my signature.

RAYMOND F. BENNETT.

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