US2287198A - Method of constructing horizontal cylindrical tanks - Google Patents

Description

J1me 1942- w. A. SANDBERG I METHOD OF CONSTRUCTING HORIZONTAL CYLINDRICAL TANKS Filed March 19, mm

2 Sheets-Sheet l WILLIAM A. SANDBERG //v VEN TOR TORNEY Juize 23, 1942. w. A. SANDBERG 2,287,198

' METHOD OF CONSTRUCTING HORIZONTAL CYLINDRICAL TANKS p V p INVENTOR M00; M.

\\ A TTORNEK Patented June 23, 1942 William A. Sandberg, Los Angeles, Calif., as-

signor-to Lacy Manufacturing Company, Los

Angeles, Calif., a corporation of California Application March 19, 1940, Serial No. 324,838

4 Claims. The invention relates to methods for constructing large cylindrical tanks in ahorizontal position.

Tanks of this form, for the storage of light liquids or of compressed gases; have now at- 5 temporaryrollers during the assembling of the tained great dimensions, as for example a diamshell; eter of thirty-two feet and a length of over two Fig. 5 is an end elevation on a reduced scal hundred feet, and the demand is for even larger of a fabricated ring showing a preferred method tanks. Because of their size, which renders it of temporarily staying it against deformation; impossible to move them any great distance, Figs. 6, 7, and 8 are elevations of a portion these containers must be constructed in the field, one-hal f the ank in va i us Stages of in the open air, and the methods conventionally sembling, and used in the shop for assembling of smaller cyl- Fig. 9 is an elevation of the entire tank at the inders either fail completely or become unduly stage at which the halves 'may be j i by the costly when applied under field conditions, 5 insertion of a single ring. p Tanks of this type are customarily made up Referring first to Figs. 1 and'2, the tank may of a plurality of rings joined end to end, the beconsidered as consisting of aplurality of ring longitudinal seams being staggered around the shaped sections |n |u- |n, aclosure in circumference and the heads being hemispheritwo girder rings l2-|2 and the two heads cal or otherwise outwardly. curved. They may I3l3.- be constructed with all the seams riveted, or a hs d rin is provided W th a ir r" M. with the longitudinal seams riveted and the shown as being placed outside the tank though roundabout seams welded, or with all the seams it y qu lly W ll be p d i The girder welded, as may be preferred, all of these alterrings a o P d W h Pa of brackets natives being found in prior practice. It is also I 5 wh h. wh n he nk is pl rest on Well known o rotate the t k at intervals, durexpansion rollers and enclosing boxes I 6 seated ing construction, to bring portions being worked on onc or o r Piers "I on into convenient locations, particularly to The first step in t e Construction o the tank bring seams to be welded into an approximat 1 is to erect on each of the foundations a girder horizontal position, ring I2 in or on which the girder has already Briefly stated, the method consists in first been perman n ly fix in p i ie ring the erecting on each of the permanent foundations n t u t p d these rings st on temp a ring-shaped section of the tank provided with a y l rs I8 su p rt f the tin s as a strong and rigid girder; in guying o br ing shown in Fig. 3. These rollers are so placed and these girder sections to prevent their being over proportioned that the k which is to be turned by a relatively small unbalanced weight; structed on them will be in its final position when in adding material (as prefabricated rings or inc mp AS Shown in Fi the r k l5 dividual sheets) on each side of each erected and expansion rollers av no ye bee section in such m nn as t avoid t great an placed at this stage. The rings are maintained overturning moment due to unbalanced weight, in an upright position by-suitable means, shown until the assembled portions of the shell ap- 4 guys though struts may be u 1 pre erre preach. to the at which the gap may be The next step is to add material on each side closed by the insertion of a single section or of i the sheets of which it is composed of each girder ring n such manner as to avo d wh an unbalanced condition exceeding the restrainerever girder .is referred to herein, ref- I in g capacity of the guying means provided. erenceismade to a circumferential girder, which This addition of material may be m the form may be inside h the shellof complete rings or of single plates, or both.

The h is 9'pl'lleiible t0 the Where complete rings are. added, which will of tanks iestins on one, two, or a greater number 0 be possible until the assembly projects at least of foundations, but'as the use of two foundations tw or three rings beyond the foundation, the I is ordinarily the best practice the method is so rings are fabricated on the ground and are illustrated in the attached drawings, in which: stayed or braced temporarily to permit them to Fig. 1 is a side elevation of the tank as cornbe lifted into position and bolted to the shell pleted and resting on its permanent foundations; sections already assembled. For this purpose Fig. 2 is a section as on the line 22 of Fig. 1;

Fig. 3 is an endelevation and Fig. 4 a side elevation of one of the girder rings resting on- I prefer the method of staying described and claimed in my copending application Serial No.

324,837, filed simultaneously herewith. This method consists briefly in placing radius rods 20 in tension between a centrally disposed disc or hub 2| and the inner face of the ring. These rods may be welded at their inner ends to the hub and also welded at their outer ends to the wall of the ring, or the rods may be passed through holes drilled in the ring and tightened and building them in place by adding a sheet ata time to the part of the shell already assembled will depend on the momentary relation between the projected length of the assembly and the strength of the guying or other restraining means.

l9. Assuming that the girder i4 is stiff enough to resist local deformation and maintain the girder ring truly circular, the projected portion of the uncompleted shell is a true cantilever beam and has no tendency to deform at its outer end. This, however, is true only as long as the plane of the girder ring is the sole plane of support. If any attempt is made to resist overturning force by supports placed under the projecting end, as

for exampleby means of blocking, the outer end of the shell will be deformed and it will be impossible to continue the'assembling. For this reason,

in following the method herein described, the guying means i9,'of whatever nature, is the sole means for resisting the tendency of the momentarily'heavier end of the shell to subside, and as the distance from the girder ring increases, this force correspondingly increases for any given increment of weight. Consequently, while it may be cheaper and more convenient to prefabricate the rings on the ground and add them as units, it is seldom or never possible to continue doing so for the entire length of the assembly, and at some point along this length (which will be determined solely by the judgment of the constructor) it will be necessary to fabricate the rings in place by adding one sheet at a time.

Whichever method of additionis followed, the unbalanced weight due to the addition of a ringor a sheet is immediately compensated by the addition to the opposite side of a corresponding element. This is illustrated in Figs. 6 to 9, inclusive. In Fig. 6 a first ring ill-ll has been bolted on the right hand of the girder ring 12; in Fig. '7 a second ring 1 2 has been added ,on the left hand, thus restoring the weight balance; in Fig. 8 three rings on each side of the girder ring have been completed and rings ll-I and "-8 have been startedby the addition of one sheet at each end of the assembly.

In Fig. 9 the shell is shown in the last stage of incompletion; the two halves (which may have beenconstructed simultaneously or successively) having approached each other until the gap can -be spanned by a single closure ring II. The

numbering of the rings on each half of the tank shows the two orders which may have been followed in adding rings or sheets. It will be noted that on the left half the order is right-left-leftright while on the right half the order is rightleft-right-left. The first order is usually more convenient. but otherwise they are strictly equivalent, the unbalance due to the addition of a single unit on one side being corrected by the following addition of a similar unit on the other '5 side of the plane of support.

As soon as the closure ring H has been bolted into place. the guying means ISmay be removed. The heads l3 are then placed and the assembling of the tank is completed. It may then be rotated 10 on the rollers It, as by means of a roundabout cable and a winch, for convenience in the ensuing operations of riveting and/or welding. The tank having thus been made tight is tested and, finally, the expansion rollers and boxes ii are placed on the piers, the brackets l5 are positioned on the boxes and attached to the girders, and the temporary rollers H! are then withdrawn, allowing the weight of the tank to rest on the brackets. The temporary rollers may be removed without lifting the tank if they are initially placed on wedges which may be driven out after completion of the job.

In case it is not desired to rotate the tank during the construction period, as for example if it is to be constructed by the addition ofsingle sheets to the girder ring and the welding of each seam as the sheet is placed, the use of the temporary rollers may be omitted. In such case the brackets l5 are attached to the girder ring when it is first erected, and the expansion rolls and enclosing boxes ii are placed between the brackets and the foundations at that time, thus bringing the girder ring into its final position at the time of erection.

If the completed tank is to be used for the storage of liquids,the girders which would be required to prevent deformation in use will be sufficiently strong and stiff to maintain the shell cylindrical during the assembling operation. It'should be noted, however, that if the tank is to be used for 40 the storage of gas under pressure, the girders calculated for the stresses existing in the use of the tank may be considerably too light to maintain the cylindrical form during assembly, and in calculating their section the stresses existing during construction should also be considered.

In the attached claims, the word foundation" is used in the singular to define the ultimate support for the tank in any one plane normal to the longitudinal axis, this ordinarily consisting of two piers which may or may not rest on a common footing.

I claim as my invention:

1. In the construction of horizontal cylindrical tanks: the step of projecting a self-supporting 5- cylinder from opposite sides of a girder-stiffened ring section resting in an erect position on a foundation, by successive additions of tank-shell material to opposite sides of said erect section,

the total weight of said section and said added" m material being transmitted through said-girder to said. foundation.

2. In the construction of horizontal. cylindrical tanks: the step of projecting a self-supporting cylindrical shell from opposite sides of a ring section stiffened by a circumferential girder and resting in an erectposition on a foundation, by successive additions of prefabricated rings of tank-shell material to opposite sides. of said erect section, said additions being made alternately on the two sides of said section, the total weight of said section and said added rings being transmitted through said girder tosaid foundation.

3. In the construction of a horizontal cylindrical tank, the steps comprising: erecting in an axially horizontal position a ring-shaped section drical tank, the stepscomprising: erecting in an 10 axially horizontal position a ring-shaped section of said tank including a stifl' circumferential. girder; bracing said girder to resist an overturning force; attaching prefabricated rings of tank shell material alternately at each end. of said section and thus forming a cylinder of progressively increasing length, and supporting said cylinder during said construction solely on a foundation bearing only against said girder-including section.

' WILLIAM A. SANDBERG.

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