US1965736A - Method of tank construction - Google Patents

Description

July 10, 1934. E. E. DILJMAN METHOD oF TANK coNsTRcTIoN Filed Jan. 26A. 1935 5 Sheets-Sheet 2 INVENTOR.

rlllllllllllllllill Ill ATTORNEY.

July l0, 1934. v E. E. DILLMAN' METHOD OF TANK CONSTRUCTION 5 Sheets-Sheet 3 Filed Jan. 26,- 1953 INVENTOR. f///z/Y/Wff,

BY v

ATTORNEY.

JUIY 10, 1934- E. E.VD1LLMAN I 1,965,736

METHOD OF TANK CONSTRUCTION Filed Jan. 26. 1933 5 Sheets-Sheet 4 July l0, 1934.

y E. E. DILLMAN METHOD OF TANK CONSTRUCTION Filed Jan. 26. 1933 5 Sheets-Sheet 5 11lIrllllllllllllllllllllllh ATTORNEY.

Patented July 1o,` 1934 UNITED STA-TES PATENT OFFICE 7 Claims. (Cl. 25J-148.2)

This invention relates to the construction of welded metal containers, such as`oil tanks, water tanks or containers of this nature for any subi ment of the plates or members of a tank can be` controlled during the welding of the tank, and to prevent them from assuming a curved shape.

Another objectof the improved methodV and means is to maintain the plates in contact at all times and in their assembled relations and to overcome the inherent shrinkage of a welded container, resulting in a symmetrical tank.

A further object of the method is that a bottom angle may be used in constructing a tank or container by preventing the stressing of the bottom angle during the welding method. Other important objects will be apparent hereinafter. The invention may be readilyy understood from a perusal of the following detailed description, taken in connection with the accompanying drawings', forming a part of this specification, and in the drawings:

Figure 1 is a side elevational view of a welded tank constructed in accordance with the improved means and method. l

Figure 2 is a plan view of a tank bottom including the bottom angle member of the tank.

Figure 3 is a vertical sectional view through the tank bottom, bottom angle member and a portion of the iirst ring or assemblage of plates, the

view being in broken formation for convenience of illustration.

Figure 4 is a View similar to Figure 3, but showing the tank parts in assembledposition `before welding, Figure 3 illustrating the tank after welding with consequent reduction of its diameter.

Figures 5, 6 and 'T are fragmentary detail sectional views respectively of modifications of overlapped construction susceptible of 'use with the method.

Figure 8 is aside elevationalview `in part of a tank wall, bottom angle member and `the tank bottom, after welding, or a developed bottom angle and first course in welded position.

showing the parts prior to welding, with the use `of devices for clamping the member in assembled position.

Figure lois a cross-sectional view on line 10-10 of Figure 8, and Figure 11 is a cross-sectional view 00 on line 11, Figure 9. y

Figure 12 is a detail view of a clamping device for holding the .plates in assembled position during the welding, the device being related but diierent from the device shown in Figure, 11.

`Figure 13 is an elevational view of the first course of shell plates in assembled position with developed bottom angle, before welding.

Figure 14 is a similar view to that of Figure 13, but showing the plates after the welding of 70. the horizontal seams.

Figure 15 is a view similar to Figures 13 and 14, but illustrating developed bottom angle and rst and second course -of shell plates after welding. 75

Figures 16 to 19, inclusive, represent diagrammatically the action and result of expansion forces and movements thereof.

Figure 20 illustrates in part the plan view of a tank bottom and its angle member, Figure 21 8G being a cross-sectional view on line 21-21 of Figure 20, these views for the purpose of illustrating faulty construction to be overcome.

Figures '22 and y23 are vertical sectional views of a tank bottom, angle member and the rst course of shell plates in position before welding, the latter (Figure 23) showing the completed bottom with the buckling removed.

Figures 24 to 29 inclusive are shown to illustrate tank construction not employed in this method and to make clear the purpose of this invention,-Figures 24, 25 and 26 .representing plan views in part of altank bottom and part of the tank shell', and Figures 27, 28 and 29 being crosssectional views of Figures 24., 25 and 26, respec- 95 tively.

Figure 30 is a sectional view of a tank which has resulted from faulty construction, causing abnormal reduction of 'capacity and lack of symmetry-the view being shown for the purpose of Y making clear the improved method and means to be now more particularly described in detail.

In Figure 1 is shown a tank constructed in accordance with the improved method and in which the seams are overlapped or in which these seams` are a. modification of overlapped construction such as is shown in Figures 5, 6 and '7. Figure i shows the construction ofv a tank ascarried outl in the improved method and thetrue relation of the l plates 2 to each other in order thatthe tank or 110 l angle as at 3.

vau

. appear will b e in diiferent and symmetrical, must be vis caused by the welding of container will be symmetrical in shape. The courses, rings, or sections of a tank, to be thus in a true vertical plane and the 'top of eachring, course or section, each horizontal seam, tal plane, or in the planes as required bythe shape and form of the container. To obtain this result and at the same time produce astructurally sound tank is the object and purpose of the method and means herein described.

In constructing the improved tank and as shown in Figure 2 the bottom plates are held in position by light tack welds 3, after being properly assembled with the bottom angle 4, also similarly tack welded to the bottom plates 2. The only `continuous welding or strength welding done on these members at this time is the welding of the overlapped seams that fall under the bottom To these seams there is'no access for welding after the bottom angle is placed inv position. This lplan view thus shows the relative position -of these members in assembled relation before any strength welding takes place. Figure 4 shows therelative position of the plates 2 which constitute the shell of the tank in assembled position prior to welding, while Figure 3 illustrates the parts after welding, the dotted lines and arrow-heads indicating diameter before and after the welding has been done'.

As previously stated, to provide a symmetrical tank, the walls or sides must be in a vertical plane change in diameter, of the rst ring, course, or section, must be controlled. A certain portion of this shrinkage comes fromthe welding of the bottom plates to each other. This is relatively small, however, as the major portion of the shrinkage the bottom angle to the bottom plates. l f

The welding of a circular section, such as abottom angle or ring, to a flat plate, such as the bot-'- tom of a container such as shown in Figures 3 and 4 causes a contraction oi the diameter of this circular section. It the that is the equivalent of the change in bottom is a. complete unit, of a solid plate, the result diameter referred to 'above bottom will rise up from the foundation at some points, since there is morev area of plate in' the bottom than required by the smaller diameter depends on conditions such as heat of the welding arc and thicknessof the respective members, the exact amount of shrinkage cannot be determined before welding takes place. The procedure and methods oi' welding andassembly must compensate for this unknown factor. x

Assuming that the bottom of the tank is -in one piece, the con bottom after Welding is: the bottom plates will not rest evenly on the foundations after the welding takes placeJ The strength of the bottom to withstand a contractive -stress applied at the outside edge of the diameter tive stress, since the bottom is in one integral unit. As this plate is circular in shape, the buckles-that varied positions. In some cases they will be under the bottom angle andin" others towards the center of the bottom.- Yr"*'*As fa-result.oi?

bottom under the this buckling condition of the bottom anglefthetop vesige B 01 dure is carried out.

of the first ring, course or section,

=welded from the inside of the of the ring. Since this change `vauras assumed that a -necting the first ring to the bottom angle was ing'of the members by each other as` the circumthe bottom angle 4 would not lie in a horizontal plane, and the upstanding leg- 'I of the angle would be in or-outside of a vertical plane as indicated by the dotted lines and arrow-head in Figure 2l. This condition can only result in a tank that is not symmetrical and in which buckles will appear in the shell.

To overcome the condition shown in Figures 20 and 2l, which is caused by the buckling ofthe bottom plates, the following method and proce- In Figure 2 is shown the bot- Y' tom, composed of the plates 2 and the bottom angle 4 in place in the assembled position-. These members are heldin such positionby vthe light tack welds 3 as previously stated. To the bottom angle 4 is attached the first ring or section, that is the plates 2 in Figure 4. The first continuousweld the weld connecting the bottom angle4to the bottom plates 2. This is shown in detail in Figure l0. Attention is calledA to the. `fact that all plates in the bottom and the bottom angles are maintained in position by light tack welds 3.' It will beassumed that a satisfactory method of attaching the first ring or course to the bottom angle is used. This ring is attached before the weld are particularly weak against a contractive force applied at the extreme edge, the vertical force A that is, weight,- will hold the angle on the foundation1 ,This will be clear from Figure 22, the first ring being indicated at 8. This arrangement forges the buckles 9 to appear in the bottom away from the edges. At the completion of the welding o'f the bottom' angle to the bottom plate, all contraction 'from 110 this welding has taken place and'has resulted in buckles in the bottom.

The bottom longitudinaf seams 10 are now bottom angle to the center of the'bottom. Y As these seams are welded, 115 the light tack welds 3 break?, or are mechanically broken, which allows each plate to shift slightly, thus compensating for the change in diameter. This shifting can readily take place, as the crossseams 11 are not welded until thelongitudinal 120 seams 10are welded. This method results in a at bottom 12 resting evenly on the grade, and having the top edge of the bottom angle in a horizontal piane and the upstanding leg. thereof A'I in a vertical plane as show`n in Figure 23.

In the above description of the method used to procure a flat, ylevel bottom and bottom angle, it

satisfactory means .of conused. A perusal of Figures 8 and 9 will show the 130 rst and primary condition to be met if a safe and structurally sound tank is to be secured. Figure!) shows an elevational view in part of the first ring of a tank attached to the bottom angle in an assembled and developed position. Figure 135 8 shows that the bottom and the bottom angle have been welded. This is a developed section and has the change in circumference as the result of this welding. As the diameter of the bottom becomes smaller, the circumference becomes smaller.

Let it be assumed that the first ring is retained f -in position by some means that prevents a lateral movement-of the plates. that is, prevents the slidference .becomes smaller. This condition r`would be secured if holes were punched in the angle and `plates so that 4these holes would match bolts or rivets used'to hold the plates inposition. See Figure 24. 'I'he bolts are indicated-at 13 and 8 1 50 10o i 3 is made, see Figure 10. As thebottom plates represents the rst ring. This arrangement would result in the condition shown in Figure or in Figure 26,l depending upon which type of bottom angle construction is used. If the construction shown in Figure 25 is used, the plates must buckle between the bolt or rivet holes or h old the bottom angle to the assembled diameter of the bottom ring. If the construction shown in Figure 26 is used, the platesmlist buckle between the plates, as shown in the drawings. The position the plates -will take depends upon the strength to withstand buckling that the first ring plates will have. As the plates must buckle against the arch of the plates/and if theplates are relatively thick and the holes relatively close together, the condition shown in Figure 24 will probably maintain. If the condition is as shown in Figure 2501 Figure 26, buckles will appear on the first ring and the ring will not have the plates in vertical plane, and the top edge of the plates will not be in ahorizontal plane. In all cases in which the bottom angle is outside of the first ring, the symmetry of the tank will not be affected, but the safety of the structure would be affected. Since the tank must maintain its assembled diameter, and as it is assumed that the first ring is rigidly fixed to the bottom angle, stresses will be set up in the bottom angle. The bottom angle will tend to contract as it is welded. It must con,- tract against the first ring, which is fixed in diameter because of the bolts 13.' The resistance of the rst ring to contraction will cause the-bottom angle to maintain its position as assembled. Since this contraction of the bottom angle does not take place, a stress must be set up, either `in bottom angle Weld or the bottom angle. If this stress is in the bottom angle. it will be a tensile stress. As the stress in the bottom angle from the loads in the tank are tensile stresses, the -net result of the stress in the bottom angle from welding is to increase the stresses by that amount. Consequently, greater stresses are built up than called for in the design.

That this has been the case and the result of such design has been established by bottom angle failures where welded bottoms have been attached tof riveted shells. In the case of riveted shells and welded bottoms, this condition has been accentuated to a maximum degree, as the shell welded to the bottom plates.

contact.

diameter must be constant and the d'ameter of the bottom and bottom angle after Welding must be restrained to this degree.

To overcome the condition described above, a clamp device is used that will hold the plates temporarily in the correct position.A Any clamp de# vice used must hold the members in contact through friction so that the members can slide by each other to compensate for the smaller dameter after welding and the smaller circumference. One type of such clamp device is shown in Figure 11.

It is imperative that the members be free to move by each other in order to compensate for the inherentl change in diameter due to the contraetion of the bottom angle or section when it is The clamp device must not allow the members to get away from the assembled position and must hold the members in This result is secured through frictional contact and as there are no means of connection through the members, they can slide by i each other as contraction takes place.

frictional force exerted by the clamp can be re- Since the contraction of the -diameter and ring, stresses cannot be builtA up in any of the welds or members. The members will be constantly in contact and will remain in their assembled relation.

Reference to'the drawings, Figures 13 to 15 inclusive, illustrates another necessary attribute of a fitting up device. Figure 13 shows a developed elevation of the first ring of a tank before welding. The plates 2 in this view are held in position byA a device that does not rest -against the edge of the horizontal seam, see Figure 1,2, as does the device shown in Figure 11. This device consists of an angular body 18 and a screw bolt 19 for frlctionally holding the bottom angle and the first ring together. Or let itV be assumed that any device maybe worked out that meets the requirements of the conditions described, and does not rest against the horizontal seam, either on the inside of the shell or Wall or on the outside. When the horizontal seam is Welded there will be a movement of the plate that is being welded, which will.

cause the plates to become curved as at 20, Figures 14 and l5, on the longitudinal edges. Figure 15 shows the same condition in the developed section of rings one above the other, or sections, of. the plates 2. By a ringis meant a circular row of plates 2. All other rings would be similarly conditioned. The result of this movement would cause the plates toshorten and result in the top of the rings falling inside of the vertical plane. The resultf of this condition would be that as the topof each ring fell inside of the vertical plane, -the finished tank would assume a shape similar to that shown in Figure 30. This form of tank would be inipractical because of the reduction in capacity, its lack of Asymmetry and the difficulty encountered in placing the supporting steel fol' the roof;

This curving'of the longitudinal edges of the plate is caused by the contraction of the plates along the edgesbeing welded. The heating caused by the welding tends to make the plate. 4

expand; but since this heat is localized at the point of welding and is gradually diffused into the colder portionsof the plate, this expansion takesplace against cold metal. This cold metal is very resistant to deformation. .As the metal at the point of welding is in a molten state, this expansion causes the vhot metal, which is much less resistant to a given force, to deform and the molecules to become closer together. The edge ofI the plate or member becomes shorter and causes the plate to take a curved position. This condition is inherent in the weldingprocess.l

In Figure 16 is shown a portion of one plate and a portion ofthe bottoni angle removed from thevshell or wall of a tank. Welding-has taken placel at the point A*. Figure 17 shows diagrammatically the expansion forces caused by the welding -resolved into vertical and horizontal forces. Similarly to Figure 17, Figure 18 shows the resultant movement of these forces. As the bottom angle is restrained by the foundation, all the movement will be in the plate, resulting in a downward and horizontal movement, as shown by the resultant. This movement will result in a deformation of the plate.

If a force is vintroduced that will oppose the vertical resultant R`V in Figure 18, the downward movement would be restrained and all movement would be in ahorizontal direction. Figure 19 shows graphically the introduction of such a forcent the point A. The bottom angle is reyic the members be allowed tion. Any other ring or course after the lower horizontal seam is Welded would also be restrained from a vertical movement, as any force tending to cause such movement would be transmitted to the foundations through the lower rings and bottom angle. This force FC as shown in Figure 19 requires that any device used be so designed and placed that any vertical force will be transmitted to members that are ilxed in position.

It becomes apparent that tack welding the plates together would satisfy the condition that a vertical movement be restrained. This method ofl erection would not satisfythe condition that to slide by each other as welding takes place. A shown in Figures 25 and the contraction due to condition similar to that 26 would result if such a a condition would jeopardize the structural integrity of thetank and must be avoided. f

A device, to be effective, must hold theplates together by friction, and this frictional` force must be vreadily adjustable so that a horizontal movement, 'vertical movement or any movement as-required by the shape and type of container can readily take place.. This movement will compensate ior the change in diameter that takes place -when the container is welded. A device must` rest on the'next lower member or be so designed that -a verticalmovement of the memb er being welded is restrained, and thus prevent a curvature of the member or plate being welded. In order to make effective vthe methods and devices described-.the vertical seams are not we1d.

eduntil all thehorizontal seams are welded.

In welding the Avertical seams last, any movement e of the members will be restrained to a horizontal A. plates when -the curb. -r'nem to the bottom movement, which will be compensated for by; the open, unjoinede seams. -The welded. horizontal seams will restrain the vertical seams to the assembled position and .insure a symmetrical tank.

'I'lie methodherein described and illustrated when used with the general type of `clamping device shown in Figure 12 will result in a sym- 'metrical and structurally, sound container. 'I'he invention is intended to embrace variations in the method of. lap welding of tanks as'stated and the clamping means may also. be alt-erated and mod ied to an extent in keeping with the appended claims, *a

What is claimed asnew isz. 1. A method oi' constructing a multi-platetank which comprises assembling plates in over-lapped position to form a bottom,

attaching a ring or section of wall platesto y the bottom angle iron, permanently welding the bottom angle iron th permanently plates. A

2. A method of makinga multi-plate structure,

vwhich comprises assembling plates in rows and in overlapped position at all meeting edges, each temporarily row comprising a pluralitywf plates, uniting the .plates by light tack welds, placing a curb member on `the plates, securing the curb memberagainst distortion'by the buckling ofthe rfshrinks in diam'- method was used. Such,v

plates, permanently welding ilrst.` Ilongitudinal seams of the bottom -plates, then ,f welding the cross .seams ot saidc 1,9ers,'z'seA strained from a vertical movement by the funda- 3. A method of constructing a multipl'ate tank accordingto c1aim.6 ,which consists. of adding additional'rings or sections to the ilrst ring or' section attached tothe curb member or bottom angler'lron by means of' -friction clamp members vrto permit lateral movement of the plates when welded .together and to prevent the plates from assuming a curvature, and welding iirst the longitudinal seams ofthe side plates, then welding the cross'seams of said plates.

4. A method of constructing a multi-plate tank which4 consists of assembling bottom plates in over-lapped relation, tack welding `the`p1ates,

placing permanent welding in the seams of thel plates; which wi1l come under a curb member, seating a curb'member with attached first ring side plates on the bottom plates, permanently welding the/curb member to the bottom plates,

Welding the longitudinal seams, and then the cross seams of the bottom plates; then using frictional means for-holding successive side wall sections of plates to said rst ring of plates, to prevent vertical movement of the member being welded to avoid curvature of the side plates, and then welding rst the horizontal seams and then the vertical seams to form the completed tank.

"5. A method of constructing a multi-plate tank which comprises attaching by means of frictional clamps the plates of the Side wall Sections or rings to a lcurb angle on theassembledbottom plates of the tank,pror to the Welding of said bottom plates, then similarly and by means oi' i'rictional lclamps attaching the plates of successive side wall sections to the next lower adjacent side wall section, said clamps being adjustable to permit adjustment of the frictional force holding the plates in contact, in order that the plates, may adjust themselves to the nal dimensions of the tank after welding.

' 6. A method of making a hollow sheet metal structure which comprises attaching by means of frictional clamps the plates of a side wallsection or ringtoa lower section or ring, then similarly.an'd by means of frictional clamps attaching ios successive side wall sections each tothe next lower section, said clamps being adjustable to temporarily uniting the plates bytack welds, placing a' bottom angle iron on the plates, retaiingthebottom angle -iron` in. position by light tack welds,

permit adjustment of the vfrictional force holding the plates in contact, in order that `the plates may adjust themselves to the ilnal dimensions of the structure after welding.

7. Av method of making va hollow sheet. metal structure vwhich comprises attaching by means of frictional clamps the plates of a side w'all section or ring. toa lower section or ring, then similarly and by means of fritional clamps attaching successive sidewall sections each to the next lower section, said clamps being adjustable to permit adjustment of the frictional force holding that the plates ilnal dimensions Welding the cirwelding the cross

Images