US2287197A - Method of constructing horizontal cylindrical tanks - Google Patents

Description

June 23, 1942. w, SANDBERG 2,287,197

METHOD OF CONSTRUCTING HORIZONTAL CYLINDRICAL TANKS Filed March 19, 1940 3 Sheets-Sheet 1 WILLIAM A. SANDBERG A TTORNE Y June 23, 1%42. w. A. SANDBERG 2,287,197

METHOD OF CONSTRUCTING HORIZONTAL CYLINDRICAL TANKS I Filed March 19, 1940 3 Sheets-Sheet 2 WILLIAM A. SANDBERG INVENTOR A TTORNEY June 23, 1942. w. A. SANDBERG 2,237,197

METHOD OF CQNSTRUCTING HORIZONTAL CYLINDRICAL TANKS Filed Mafch 19, 1940 3 SheetsSheet 3 WILLIAM A. SAN DB ERG INVENTOR A r TQRNE Y Patented June 23, 1942 METHOD OF CONSTRUCTING HORIZONTAL CYLINDRICAL TANKS William A. Sandber Los Angel'es, Calif., assignor to Lacy Manufacturing Company,

Los

Angeles, Calif., a corporation of California Application March 19, 1940, Serial No. 324,837

(Cl. 29-1482) s 3 Claims.

The invention relates to methods for constructing large cylindrical tanks in a horizontal position.

Tanks of this form, for the storage of light liquids or of compressed gases, have now attained great dimensions, as for example a diameter of thirty-two feet and a length of over two hundred feet, and the demand is for even larger tanks. Because of their size, which renders it impossible to move them anyv great distance, these containers must be constructed in the field, in the open airgand the methods conventionally used in the shop for the assembling of smaller cylinders either fail completely or become'unduly ccstly when applied under field conditions.

Tanks of this type are customarily-made up of a plurality of rings joined end to end, the longitudinal seams being staggered around the circumference and the heads being hemispherical or otherwise outwardly curved. They may be constructed with all theseams riveted, or with the longitudinal seams riveted and the roundabout seams welded, or with all the seams weld- The improvements making up the present invent'ion comprise:

(a) The assembling of the tank from completerings assembled and at least bolted up ina vertical position on the-ground, stayed against deformation and thereafter lifted into the horizontal position;

(b) A novel method for staying the rings'to prevent their deformation or collapse while being handled and assembled;

(c) A novel method and means for supporting the tank while under construction and for setting it accurately on its permanent foundations.

As the terms vertical" and horizontal are likely to be confusing when applied to rings of which the diameter may be four or more times the -length,it is premised that either term is applied herein solely to the 'cylindrical axis of the tank onto the ring rather than to thema advantages set forth in the accompanying drawings andthe following description thereof, in

which:

Fig. 1 is an elevation, on a minute scale, of a. completed tank on its permanent foundations;

Fig.'2 is a plan view, on the same scale, showing the location on the jack foundations;

Fig. 3 is a fragmentary sectional view showing the location of the jacks as regards the circumference of the tank;

Fig. 4 is a diagram showingthe manner of connecting the battery of jacks with the source of hydraulic fluid;

Fig. 5 is a sketch showing a single ring in the position in which it is constructed;

Fig. 6 is an end view of a ring illustrating the method of staying the rings against deformation;

Fig '7 is a detail of a means for securing the ends of the stay rodsto the ring, and

Fig. 8 is an elevation of a ring in position .on the jacks. and another ring approaching that position. v

Referring first to Fig. 1, the completed tank indicated generally at l0 consists of a plurality of rings ll-ll and the heads l2l2. The tank is provided with brackets |3l3 resting on expansion rollers l4l4 which in turn rest on structural steel or other columns l5-l5 supported by permanent concrete foundations |6l6. The tank is also provided with girdersv 36-36 which in this embodiment are shown as located inside the tank, though they may be placed outside if preferred.

The first step in the construction of plurality of jack foundations |'I-l1 spaced approximately as shown in Figs. 2 and 3. That is to say, the longitudinal spacing is such that the centers of the blocks coincide with the centers of length of'the rings; the blocks are arranged in straight lines parallel to and equally spaced from the axis of the tank location, and the lateral spacing. is such that the centre of theblock is intersected by a radius which may be say 20/30 from the yertical. v I

On each of the foundation blocks is placed a hydraulic jack [8 which preferably but not necessarily carries at its upper end a roller l9.

These rollers; if used, facilitate the welding op erationv by, permitting the tank to be rotated in the cradle formed bythe two lines of rollers.

The entire assembly of jacks is connected as shown in Fig. 4 to any source of hydraulic fluid (preferably water) under pressure, as for exama tank by the method herein proposed is to .provide a riveted butt straps. Fig. shows such a com- 35. These are all manually operated valves, as

for example globe valves or water cocks.

It is essential that all of the jacks be connected to a common sourceof supply, and it is also most desirable that all of the valves above described be provided. The purpose in placing all the Jacks in communication, as they will be with all the valves except bleeder valves 35 open (their nor.- mal operating position) is to cause the jacks to exercise an equal lifting effect even though the surface against which the rollers bear is out of round and/or out of alignment longitudinally, or

- in case individual foundation blocks should sub-- side below their original level. This greatly reduces the cost of jack foundations as they can be relatively light and shallow.

The four valves 28-3l have two uses. With all the jacks in communication, a temporarily unbalanced load such as may be produced by a concentration of workers or machinery in one end of the shell may cause that end to subside below its normal level, correspondingly raising the other end. In such event the shell may be leveled by closing one pair of valves, as for example 29 and 3|, leaving the corresponding pair open and feeding a small amount of hydraulic fluid, and again opening these valves after level has thus been restored. Similarly, the shell may be moved over a short distance laterally by closing one pair of valves, as for example 30 and 3! and feeding hydraulic fluid through the opposite pair.

The individual inlet and bleeder valves 34 and 35 are used to collapse a single jack in order to pass it over an obstruction. For example, in rotating the tank, a butt strap or rivet head may engage a jack roller, and in such case a high 1'0- tating force is required to cause the roller to ride over the obstruction by displacing fluid into the remainder of the jacks. This application of force is avoided by closing valve 34 of this individual jack and opening bleeder valve 315, permitting the pleted ring H with the stay rods in place.

when the ring proper is completed, it must he stayed to prevent deformation, as the ratio of ring diameter to sheet thickness is so greatzthat- I the rings have no intrinsic stifiness whatever.

Heretofore stays in compression-i. e., timber or steel braces-have been used for similar purposes, but the weight and cost are excessive, and I have substituted braces in tension with a highly material economy and an increased ease of handling. Diametric stay rods even if arranged of equal angles do not answer the purpose, as while such stays maintain opposite points of the circumference equally distant, they do not necessarily maintain the circular form; in fact if the ring. be suspended at two points it assumes a pear-shaped outline which cannot be mated to the part of the shell already assembled. I have therefore devised the method of staying shown in Fig.6.

In this structure, 31 is a centrally'located disc of steel plate and 38-38 are radial tie rods welded or otherwise fastened to the plate as at 39. These rods may be threaded at their outer ends, passed through the clips (Rig. 7), and tightened by.means of nuts 4|. The clips may be welded or'bolted to the-ring or, if preferred, the rod ends themselves may be welded lightly thereto. The radial angles should be equal and any desired number of stay rods may be used, in-fact in very large rings it may be desirable to use two discs spaced one-third or one-half the length of the ring and a set of stay rods projected from each. This method of staying provides a ring which is stiif without being rigid; so that it may be lifted and swung into place without deforming while having enough local flexibility to permit it to be mated readily with the ring in place to which it is'to be joined. s

The next step in construction is to assemble the rings on the cradle formed by the jacks. Assembly may be started at any point along the length of the tank, usually at the end farthest from the ring assembling .platform. A ring Ila. is picked up by a crane, using the sling indicated at .42 in Fig. 8, is set in place on one pair of Jacks (the inlet valves on all being closed),

1 is lifted to the desired level for construction by found convenient, the jacks are set at such height that the tank constructed on them is clear of these foundations. If the main and service lines are laid and provided with valves, it is not necessary to put the jacks themselves into place until they are required, when they can be set in pairs I as rings are ready to be placed on them, thus keeping the working space substantially clear.

The above described supporting and operating elements having been provided, the first step in the actual construction of the tank is to set up and stay the rings ll of which it is composed,

these rings being built meet a time as they are assembled to form the complete shell. This operation is performed on a reasonably level surface at or near ground level, the curved sheets being placed vertically to form the ring and the ends joined in the preferred manner, ordinarily by manipulating the valves of the'two jacks supporting it. and-finally is guyed as at 43-43 in Fig. 8 to prevent it from overturning. The next ring lib is then picked up and swung into place on the next pair of jacks and fastened to the first ring. by the usual bolt clips 44, and this operation is repeated until the length of the shell is complete, admitting fluid to each pair of jacks as soon as the ring is in place over them. Only the first ring is guyed and the guys maybe removed as'soon as two or three rings are bolted together.

If it is desired to locate the girders inside the tank, as shown in this illustration, it is preferable to-place them in the appropriate rings while the latter are being constructed on the When the cylindrical portion of the shellhas been assembled and bolted up, the heads are placed and the tank is finished by any preferred riveting or welding operations. Ordinarilythe longitudinal seams will have been finishedin advance and only the roundabout seams will remain to be formed. During this operation, and particularly when welding, it is desirable to rotate the tank on the cradle formed by the jack rollers, so as to bring the seams being worked on into the most convenient position. This may be done by means of an encircling cable and a winch. To avoid tipping of the jacks while rolling the tank on them, it is desirable to connect them in pairs by beams such asindicated at 45 in Fig. 3.

The tank is now tested for tightness, usnsuy with air pressure, after which a part of the testing pressure is relieved and any external girders are placed and welded to the shell. The

tion, and assembling said rings end to end; resting each ring as assembled on two points of support; hydraulically applying a lifting effect to said supporting points as said rings are rested thereon and thereby bringing the adjacent ends of said rings into abutting position; joining said abutting ends to form a continuous cylinder and maintaining said lifting effects in hydraulic balance during said joining step to provide uniform support for said cylinder and prevent distortion thereof; attaching, heads to the ends of said cylinder to forms. substantially closed tank, and finally lowering said tank into its permanent position by withdrawing said hydraulic effect.

tank is then shifted, laterally and longitudinally I, as may be required, into its exact position over the permanent foundations, and is leveled; The

brackets 13 and expansion rollers M are then put into place and the brackets fastened to the tank, or to the outer face of the girder, according to the location of the girder. Finally, the hydraulic pressure is removed from the jacks, which are withdrawn; the tank is deflated; and the stays and hub plates are removed through a manhole. The clips 40 may be left in position 92' knocked oil as may be preferred, and the stays quired for the tank by joining the straight ends of arcuately curved sheets; staying-said rings to" prevent deformation when said rings are lifted;

' lifting said rings to an axially horizontal posiand hubs'salvaged for use in succeeding con- 2. A method of staying cylindrical tank sections against deformation while assembling said sections to form a cylinder which comprises: extending radial tension members from a common center to substantially equally spaced points adjacent the inner wall of said section, and (attaching'the outer ends of said members to said wall in such manner as to place all of said members in substantially equal tension.

3. In a method of constructing horizontal cylindrical tanks which consists substantially in joining the ends of preformed and stayed cylindrical rings while said rings are assembled in end abutment and in axially horizontal position: the steps of. resting each said ring during the assembling operation on two points .ofsupport,

of hydraulically applying a lifting effect to said completed.

WILLIAM A. SANDBERG.

Images