US 3486286 A
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Dec. 30. 1969 w. SAMAGA 3,486,286
YIELDABLE WALL ASSEMBLY FOR THE TRANSPORTATION OF LOW-TEMPERATURE FLUI DS Filed April 12, 1968 3 Sheets-Sheet 1 INVENTOR.
WILHELM SAMAGA F l G 8 BY WxQ jbsi ATTORNEY Dec. 30. 1959 w. sAMAGA 3,486,286
YIELDABLE WALL ASSEMBLY'FOR THE TRANSPORTATION OF LOW-TEMPERATURE FLUIDS Filed April 12, 1968 I 3 Sheets-Sheet 2 INVENTOR.
WILHELM SAMAGA BY R99 ATTORNEY W. SAME GA YIELDABLE WALL ASSEMBLY FOR THE TRANSPORTATION Dec. 30, 1969 v 0F LOW-TEMPERATURE FLUIDS Filed April 12, 1968 3 Sheets-Sheet 5 FIG.5
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ATTORNEY United States Patent 3,486,286 YIELDABLE WALL ASSEMBLY FOR THE TRANSPORTATION OF LOW-TEMPERA- TURE FLUIDS Wilhelm Samaga, Trostberg, Germany, assignor to Linde Aktiengesellschaft, Wiesbaden, Germany, a corporation of Germany Filed Apr. 12, 1968, Ser. No. 721,043 Claims priority, application Germany, Apr. 25, 1967, L 56,338 Int. Cl. E0411 1/76; E0411 7/04 US. Cl. 52-410 10 Claims ABSTRACT OF THE DISCLOSURE A receptacle assembly for the retention of low-temperature fluids comprising a plurality of plates having parallel end edges and a pair of inwardly directed lateral edges, the edges being formed with upwardly and outwardly turned flanges welded together at their corners to form pans and to adjoining plates of corresponding configuration so that the junctions of the end edges of each row of plates is offset from the junctions of the end edges of an adjoining row, the plate is secured to a rigid wall, with interposition of a thermally insulating layer, via thermally nonconductive bolt assemblies anchored at the midpoint of the double trapezoids formed by each plate.
My present invention relates to containers for the transportation of low-temperature fluids and, more particularly, to a tank or compartment in a seagoing vessel for the transportation of liquefied gases at low temperature.
In the commonly assigned copending application Ser. No. 664,066, filed Aug. 29, 1967 by myself, Hans Pro'gler, Hermann Ehms and Rudolf Eickemeyer, entitled Tankship for Liquefied Gases, there is disclosed a tankship for the transportation of liquefied gases (e.g. liquid hydrocarbons such as methane, ethane or propane, or airrectification products such as nitrogen, or ammonia) whose hull forms a hold containing a plurality of tanks thermally insulated from the hull and separated therefrom by a continuous sheet-metal skin. The skin, which may flex in response to temperature fluctuations, is composed of plates welded together in fluid-tight relationship along their peripheries at upstanding flanges so that the welded peripheries form expansion joints or folds accommodating expansion and contraction of the skin. Between the sheet-metal skin and the hull of the ship, there is provided a layer of insulation preferably of load-supporting or relatively incompressible character. In addition, the system of that application provides parallel arrays of shear-rail assemblies supporting the tank in loadtransmitting relationship with the hull while thermally insulating the tank therefrom. The earlier application, Ser. No. 663,577, filed Aug. 28, 1967 by Rudolf Becker and also commonly assigned, describes an improvement in which insulating bolts attach the sheet metal outer wall of a double-wall assembly to the hull of the ship with an intervening layer of load-supporting insulation. As pointed out there, a further layer of insulation, preferably of the nonsupporting type, may be interposed between the inner wall of the vessel and this intermediate sheet-metal layer. The bolt assembly described in that application comprises a bolt head welded sealingly to the sheet-metal layer and whose shank is threaded into a cylindrical post of thermally insulating material, the post being threadedly anchored in a sleeve upstanding from and welded to the hull of the vessel.
In the sheet-metal skin of the aforementioned copending applications, elasticity is gained by providing a 3,486,286 Patented Dec. 30, 1969 ice plurality of plates in contiguous relationship, the plates having upturned flanges at their peripheries welded at the corners to form individual pans. The flanges, which diverge upwardly, are welded together at outer lips to form a continuous partition or wall precluding passage of fluid therepast. The flanges or upwardly bent edge portions, when welded together, form folds in the continuous wall which permit expansion and contraction of the sheets in response to the high temperature fluctuations which are sustained by the walls upon filling of the tanks or discharging of the cargo. When the plates are generally retangular, they are characterized by a rigidity enhanced, in part, by the fact that the folds are lined up and are incapable of yielding satisfactorily in the longitudinal direction of these folds. As a consequence, the plates must sustain considerable stress which gives rise to a tendency to tearing at the locations at which the plates are aflixed to the hull structure or the outer rigid vessel wall.
It has been found that the individual mounting of the fixed point of an intermediate or inner sealed sheet-metal skin for tankships and receptacle structures accommodated within the hull of a seagoing vessel, as proposed heretofore, is relatively complex and expensive when accomplished in the manner described above.
It is, therefore, the principal object of the present invention to provide an improved yieldable wall structure for a vessel of the character described in which the stress applied to the plates is decreased and the mounting assembly prevents tearing of the sheets.
It is another object of the present invention to provide an improved mounting assembly for hermetically sealed sheet-metal walls spaced from the hull of a ship by a layer of load-supporting thermal insulation.
According to an important feature of this invention, the stress developed in the individual plates, which are peripherally welded together in contiguous relationship to form a continuous fluid-tight partition adapted to withstand low-temperature fluids, is relieved by offsetting the junctions between the plates, from plate to plate along the continuous skin. This is accomplished by imparting to the plates a geometric configuration which corresponds, substantially, to a double-trapezoid joined at the corresponding small base thereof. More specifically, the plates are provided with a pair of parallel end edges and a pair of inwardly directed lateral edges and are joined together in overlapping relationship so that the junction between a pair of ends of end-aligned plates is disposed substantially intermediate the ends of the neighboring side-aligned plates. Thus the plates of the present invention are connected end to end in adjacent rows which are offset substantially by about half the length of the plates and each plate is widest at its ends and narrowest at an intermediate region corresponding to the location of closest approach of the inwardly turned lateral sides. Preferably, this intermediate location lies at the center of the plate. As in the prior systems, each of the edges is formed with an upwardly and outwardly turned flange, the flanges along the periphery of each plate being welded together at their corners, A single bolt assembly (e.g. as described and claimed in my concurrently filed copending application Ser. No. 721,042 entitled Tank Assembly for the Transportation of Low-Temperature Fluids) secures the plate to the rigid wall at the center of the plate.
According to a more specific feature of this invention, the lateral edges of each plate include acute angles of 60-80 with the parallel ends and thereby intersect at an obtuse angle of substantailly -160 at the midsection of the plate so that an axial plane through the fastening-bolt assembly intersects the lateral edge of the plate at these junctions. This plane thus can be considered to divide each plate into a pair of mirror-symmetrical trapezoids formed integrally with one another at the short base corresponding to the line at which the plane intersects the plate.
According to still another feature of this invention, each of the upwardly and outwardly turned edge flanges is bent outwardly with a radius to form a lip whose flank lies perpendicularly to the body of the plate and is welded in abutting relationship to the confronting lip of the tapering plate.
It will be understood that the parallel end edges of the plates may be so widely spaced that the lateral edges are turned alternatively, inwardly and outwardly so as to encompass several pairs of back-to-back trapezoids and that the parallel edges themselves of a number of pans may be integral and the folds formed by bending the plates rather than welding plate sections together. This arrangement is particularly desirable when plates of up to meters in length are used.
Another feature of the invention resides in the use of a snap-type junction between a supporting post and the sheet metal intermediate wall or skin by providing each of the sheet metal plates of the skin with a throughgoing aperture at its single fixed point and surmounting this aperture with a cap whose interior registers with the aperture and is peripherally welded to the sheet metal at a seam spacedly surrounding the aperture. The mounting assembly comprises an upstanding post of thermally insulating material, which may be threadedly received in a sleeve welded to the hull of the ship, the post being formed with an upstanding pin adapted to pass through the aperture of the sheet metal skin and to be received in the cap disposed thereabove. A spring ring is anchored in the cap and is designed to snap into a circumferential groove formed in the pin beyond a conical spreading head of the bolt whose small-diameter tip is receivable within the ring to expand the latter. Thus the inner diameter of the ring, in its relaxed condition, is less than the outer diameter of the spreading cone or tip at the upper end of the shank of the pin or both. The interior of the cap may be formed with an inwardly open circumferential groove receiving the ring and adapted to lock the ring and the pin against movement in the spread condition of the ring.
According to a more specific feature of the invention, the cap is provided with an outwardly extending peripheral flange whose axial face lies flush with the corresponding surface of the sheet metal skin and is peripherally welded thereto. The pin, according to the present invention, is anchored in an insulating post but need not be threaded into the latter. Thus, I provide a stepped bore in the insulating post with a smaller diameter portion registering with the aperture in the sheet metal skin and a larger diameter portion disposed between the smaller diameter portion and the tankship hull or outer wall of a double-wall tank. The junction between the larger and smaller diameter portions of the bore forms a shoulder against which the pin is seated at its end remote from the frustoconical camming portion.
The remote end of the pin may be provided with a head or, in accordance with still another specific feature of this invention, a frustoconical tip symmetrical with that head at the upper end of the pin and a corresponding groove in which a spring ring is anchored to retain a washer against the shoulder of the post.
The above and other objects, features and advantages of the present invention will be more readily apparent from the following description, reference being made to the adcompanying drawing in which:
FIG. 1 is a plan view of a portion of an intermediate sheet metal skin for tankships and the like embodying the present invention;
FIG. 2 is a detailed view, drawn to an enlarged scale of part of this skin;
FIG. 3 is a cross-sectional view taken along the line IIIIH of FIG. 2;
FIG. 4 is a cross-sectional view taken along the line IVIV of FIG. 2;
FIG. 5 is a cross-sectional view taken along the line VV of FIG. 1;
FIG. 6 is a view corresponding to FIG. 5 showing another embodiment of this invention;
FIG. 7 is a diagram of the snap-lock arrangement of this invention; and
FIG. 8 is a plan view illustrating another feature of the invention in diagrammatic form.
In FIGS. 1 and 2, I show a sheet metal intermediate skin adapted to yield with temperature variation (FIG. 2) and comprising a plurality of sheet metal plates 1 of double-trapezoidal configuration. The plates are formed with mutually parallel end edges 24, forming the longer bases of the two trapezoids constituting each plate, and with inwardly extending lateral edge portions 22 and 23 including acute angles with the respective bases and intersecting substantially at the welded seams 25'. The seams 25' constitute junctions between the edges 22 and 23 along each side of the plates 1. At the junctions between the portions 22 and 23 and the ends 24 of each plates, further welded seams 25 are provided. Each of the plates 1 thus forms an upwardly open pan as described earlier.
As will be apparent from FIG. 5, each of the lateral walls 22, 23 and the end walls 24 is constituted of upwardly and outwardly turned flanges 1d, 1e shown for the respective plates 1a, 1b and 10 illustrated to lie in contiguous relationship in FIG. 5. The flanges 1d and 1e are turned outwardly at angles of approximately 10 to 20 from the vertical (angle 5 in FIG. 3) and have bent-over lips 26 whose outer flanks 26 lie in the vertical plane P of each junction and are butt welded to the confronting flanks of the adjoining flanges.
Referring again to FIGS. 1 and 2, it can be seen that the adjoining plates have their end junctions A, B, C offset from the junctions A, B, C' by approximately half the length of the plates 1 and that each of the plates 1 is retained upon the rigid wall by a single bolt assembly represented generally at 27 and located at the center of the respective plate. The bolt asesmbly is deisgned to prevent transfer of heat to and from the plates 1.
In FIGS. 2-4, the shrinkage and expansion of the plates is represented. In these figures, the position of the plates upon welding and after mounting the assembly is represented by solid lines while the position of the plates upon introduction of low-temperature fluid (e.g. liquefied gases) into the tankship hold is represented by dot-dash line. When the plates 1 are chilled, the shrinkage results in a contraction of the longitudinal edges 24 and a deflection of the lateral edges 22 and 23 into the dot-dash line position illustrated in FIG. 2, the edges 22 and 23 assuming an angle a. The angle or should range from 60 to The foreshortening of the plates causes the deflection of folds illustrated by dot-dash line 1n FIGS. 3 and 4. In FIG. 8, I show a system in which the end edges 34 are spaced up to 20 meters apart and may be welded to other plates or constitute the sides of the compartment as desired. In this case, the inwardly turned lateral edges 32 and 33 do not intersect directly but are spaced by intervening stretches 33' and 32' so as to provide a pair of double trapezoids separated by the dot-dash line 34'. A further fold, parallel to the folds 34 may be provided along this line, preferably unitarily with the plate 31. Referring again to FIG. 1, it can be seen that the intersecting seams 25 of the lateral edges 22, 23 coincide with the vertical plane P through the bolt assembly 27 (see FIG. 5).
As can be seen from FIGS. 5-7, between the sheet metal skin formed by plates 1 and the steel hull 8 of the ship, I provide a layer 8a of load-supporting thermal insulation, as described in application Ser. No. 664,066, to form a thermal barrier preventing heat loss from the tank compartment defined by the sheet metal skin to the wall 8 of the vessel.
A typical insulating material is Ferrozel (i.e. shearresistant and compression-resistant fiberglass-reinforced phenolic resinsee French Patent 1,490,834).
To secure the sheet metal plates 1 in place, I provide each with the assembly 27 which includes an upstanding internally threaded sleeve 9 having a height equal only to a small fraction of the spacing of the plates 1 from the hull 8 and welded to the latter along a seam 9a. A post 10 of load-supporting material of poor thermal conductivity (e.g. Ferrozel or a ceramic thermal insulator) has a threaded portion 10a screwed into the sleeve 9 so that the outer periphery of the post It) is flush with the outer periphery of this sleeve. The post 10 is formed with a stepped bore whose large-diameter portion 10b joins the small-diameter portion 100 at a shoulder 10d serving to anchor the head 11a of a pin 11 extending upwardly through the small-diameter portion 100 and having a frustoconical end 1117.
The sheet metal skin 1 is formed at each of its fixed points with an aperture 1 registering with the bore 10b, 10c and with the internal cavity 4 of a cap 3.
At its lower end, the cap 3 is formed with an outwardly extending flange 3a lying flat against the sheet metal skin 1 and peripherally welded thereto at 6. Within the interior 4 of the cap 3, I have provided an inwardly open peripheral groove 5 which receives a spring ring 14 adapted to be wedged outwardly by the frustoconical upper end 11b of the bolt 11 as the cap 3 is thrust over this bolt. Behind the frustoconical tip 11]), the bolt or pin 11 is formed with an outwardlly open circumferential groove 13 adapted to receive part of the ring 14 when the latter springs back after it has been wedged outwardly. To support the bolt 11, I provide a backing block 12 of thermally insulating material which fills the large diameter portion 16b of the bore of post 10 and is seated against the hull 8.
As can be seen from FIG. 7, the frustoconical end 11!) of the pin 11 has an outer diameter d which is less than the inner diameter D of the ring 14 in its relaxed position. After the caps 3 have been welded to the plates 1, the plates may be placed with their apertures 1g over the pins 11 and set by relatively light taps upon the caps 3. The taps drive the caps 3 over the frustoconical tips 11b of the bolt 11 until the rings 14, which initially are spread in the direction of arrows 1417, spring back into the grooves 13, thereby retaining the plates upon the pins. An extremely rapid rate of assembly is thus permitted.
In the embodiment of FIG. 6, a cap is provided to retain the sheet-metal skin 1' upon the bolt 11' in the manner illustrated in FIGS. 5 and 7. In this embodiment, however, the lower end of the bolt 11 is formed with a frustoconical tip 115' behind which a circumferential groove 15 is formed. A split ring 16 is snapped into this groove and bears against a backing washer 17 to anchor the bolt 11 against the shoulder 10d of the post 10 which otherwise has the configuration previously described. The cylindrical block 12 here supports the frustoconical end 11b of the bolt.
1. In a receptacle for the storage or transportation of low-temperature fluids wherein a fluid-tight elastic sheetmetal wall is spaced from a rigid wall by a layer of thermal insulation, the improvement wherein said elastic wall comprises a plurality of adjoining rows of generally similar plates, each of said plates having a pair of parallel end edges constituting relatively wide portions of the plate and inwardly turned lateral edges forming at a region of closest approach a relatively narrow portion of the plate, said edges each being provided with upwardly and outwardly turned flanges welded together at the corners of each plates to form a respective pan therefrom, the flanges of the lateral edges of said plates of each row being welded to the contiguous flanges of the lateral edges of the plates of an adjoining row being oflset relatively to dispose the ends of the plates of one row substantially at said regions of the plates of an adjoining row.
2. The improvement defined in claim 1, further comprising a bolt assembly of relatively low thermal conductivity securing each of said plates to said rigid wall at substantially the geometrical center of the plate.
3. The improvement defined in claim 2 wherein said flanges have outwardly turned lips welded to the juxtaposed lips of the flanges of the adjoining plates.
4. The improvement defined in claim 2 wherein the end edges of the plates on each row are welded together contiguously.
5. The improvement defined in claim 2 wherein each of said plates has the configuration of a double trapezoid With coincidental small bases.
6. The improvement defined in claim 5 wherein each of said bolt assemblies comprises a load-supporting post secured to said rigid wall and extending toward said elastic wall, a pin anchored in said post and extending therebeyond away from said rigid wall, each of said plates being provided at its geometrical center with an aperture receiving the corresponding pin and a cap sealingly anchored to the plate and having an interior registering with said aperture for receiving an end of the corresponding pin, each cap and pin being formed with spring-ring means for locking the cap onto the pin upon insertion of the pin into the cap.
7. The improvement defined in claim 6 wherein said cap is formed with an inwardly open peripheral groove, said spring-ring means including a resilient ring receiving said groove, said end of said pin having a frustoconical configuration and being receivable in the respective ring to expand same, each pin being provided with an outwardly open circumferential groove behind the frustoconical configuration of said end to receive said ring upon its expansion by said end of said pin.
8. The improvement defined in claim 7 wherein said post is formed with a stepped bore having a large diameter portion and a small diameter portion defining between them a shoulder anchoring said pin against movement in the direction of said elastic wall, said pin having another end spaced from said rigid wall, said assembly further comprising a thermally insulating block received in said large diameter portion of said bore and seated against the other end of said pin and said rigid wall.
9. The improvement defined in claim 8 wherein each of said caps is formed with an outwardly extending annular flange lying flat against the respective sheet-metal plate and being peripherally welded thereto.
10. The improvement defined in claim 8 wherein said assembly further comprises a sleeve welded to said other wall and threadedly receiving said post.
References Cited UNITED STATES PATENTS 3,367,699 2/1968 Witt 52- 110 X 3,302,358 2/1967 Jackson 52573 2,876,927 3/1959 Henning 52573 X 2,736,400 2/1956 Gay et al 52573 X FRANK L. ABBOTT, Primary Examiner S. D. BURKE III, Assistant Examiner US. Cl. X.R.