U.S. patent application number 12/904598 was filed with the patent office on 2011-02-03 for expandable metal membrane with orthogonally isotropic behavior.
This patent application is currently assigned to SAMSUNG HEAVY IND. CO., LTD. Invention is credited to CHANG-SEON BANG, SANG-EON CHUN, KI-HUN JOH, BU-GI KIM, BYOUNG-JUNG KIM, BYUNG-CHUL KIM, JIN-GYU KIM, PO-CHUL KIM, SEONG-SU KIM, DAI-GIL LEE, KWAN-HO LEE, SANG-WOOK PARK, SOON-HO YOON, HA-NA YU.
Application Number | 20110027604 12/904598 |
Document ID | / |
Family ID | 41217238 |
Filed Date | 2011-02-03 |
United States Patent
Application |
20110027604 |
Kind Code |
A1 |
JOH; KI-HUN ; et
al. |
February 3, 2011 |
EXPANDABLE METAL MEMBRANE WITH ORTHOGONALLY ISOTROPIC BEHAVIOR
Abstract
In a metal membrane for a low-temperature-fluid storage tank
wherein longitudinal and transverse corrugations are formed and
both corrugations intersect each other, a bidirectional expandable
member connected to each corrugation is formed in the intersection
of the corrugations so that the bidirectional expandable member is
longitudinally and transversely expandable. The bidirectional
expandable member is protruded and is shaped like a pyramid, a dome
or a cross. Each metal membrane is welded into a unit panel and the
edge of each metal membrane is welded with the common edge of
another adjacent metal membrane.
Inventors: |
JOH; KI-HUN; (GEOJE-SI,
KR) ; CHUN; SANG-EON; (SEOJE-SI, KR) ; BANG;
CHANG-SEON; (GEOJE-SI, KR) ; LEE; DAI-GIL;
(JEONMIN-DONG, KR) ; KIM; BYUNG-CHUL; (YEONJE-GU,
KR) ; KIM; BU-GI; (BUK-GU, KR) ; KIM;
JIN-GYU; (CHANGWON-SI, KR) ; YOON; SOON-HO;
(NAM-GU, KR) ; PARK; SANG-WOOK; (NAM-GU, KR)
; LEE; KWAN-HO; (SEOUL, KR) ; KIM; SEONG-SU;
(GEOJE-SI, KR) ; KIM; BYOUNG-JUNG; (SUNCHANG-GUN,
KR) ; KIM; PO-CHUL; (CHEONGDO-GUN, KR) ; YU;
HA-NA; (MUNGYEONG-SI, KR) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
SAMSUNG HEAVY IND. CO., LTD
SEOUL
KR
|
Family ID: |
41217238 |
Appl. No.: |
12/904598 |
Filed: |
October 14, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/KR2009/001946 |
Apr 15, 2009 |
|
|
|
12904598 |
|
|
|
|
Current U.S.
Class: |
428/573 |
Current CPC
Class: |
F17C 2223/0161 20130101;
F17C 2203/0617 20130101; F17C 2203/03 20130101; F17C 2260/013
20130101; F17C 13/004 20130101; F17C 2270/0107 20130101; F17C
2223/033 20130101; F17C 2201/0147 20130101; F17C 2260/011 20130101;
F17C 2209/221 20130101; Y10T 428/12201 20150115; F17C 2203/0685
20130101; F17C 2209/232 20130101; F17C 3/027 20130101; F17C
2221/033 20130101; F17C 2260/016 20130101; F17C 2203/0636 20130101;
F17C 2270/0105 20130101 |
Class at
Publication: |
428/573 |
International
Class: |
B21H 8/00 20060101
B21H008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 21, 2008 |
KR |
10-2008-0036754 |
Claims
1. A metal membrane with having orthogonally isotropic behavior in
a metal membrane of a low-temperature-fluid storage tank having
longitudinal and transverse corrugations which intersect each
other, wherein: a bidirectional expandable member connected to each
corrugation is formed so that the bidirectional expandable member
is longitudinally and transversely expandable at an intersection of
the corrugations; the bidirectional expandable member is protruded
in a pyramid shape, and first caved grooves are formed at corners
where lateral faces of the bidirectional expandable member are
connected; second caved grooves are formed on a top part of the
portion connected with the bidirectional expandable member in the
corrugations; and clamping parts protruded to be clamped by a
clamping unit are formed at both ends of the corrugations connected
to the bidirectional expandable member.
2. The metal membrane having orthogonally isotropic behavior of
claim 1, wherein the upper part of the clamping part is more
protruded than the bottom part of the clamping part.
3. A metal membrane having orthogonally isotropic behavior in a
metal membrane of a low-temperature-fluid storage tank having
longitudinal and transverse corrugations which intersect each
other, wherein: a bidirectional expandable member connected to each
corrugation is formed so that the bidirectional expandable member
is longitudinally and transversely expandable at an intersection of
the corrugations; the bidirectional expandable member is protruded
in a dome shape; a neck part is formed at the portion where the
bidirectional expandable member is connected in the corrugations;
and clamping parts indented to be clamped by a clamping unit are
disposed at either sides of the bidirectional expandable member
between portions where the bidirectional expandable member and the
corrugation are connected.
4. A metal membrane having orthogonally isotropic behavior in a
metal membrane of a low-temperature-fluid storage tank having
longitudinal and transverse corrugations which intersect each
other, wherein: a bidirectional expandable member, protruded in a
cross shape and connected to each corrugation between branching
parts of the cross shape, is formed so that the bidirectional
expandable member is longitudinally and transversely expandable at
an intersection of the corrugations; and clamping parts are formed
in such a way that the clamping parts are clamped by a clamping
unit at either lateral face of the branching parts by having the
bidirectional expandable member protrude over the corrugations.
5. The metal membrane having orthogonally isotropic behavior of
claim 4, wherein a side shape of the bidirectional expandable
member is a fan shape.
Description
PRIORITY CLAIM
[0001] This application is a continuation and claims the benefit of
priority under 35 U.S.C. .sctn..sctn.120, 365, and 371 to Patent
Cooperation Treaty Patent Application No. PCT/KR2009/001946, filed
on Apr. 15, 2009. This application further claims the benefit of
priority to Korean Application No. 10-2008-0036754, filed Apr. 21,
2008. The disclosures of the above applications are incorporated
herein by reference in their entireties.
TECHNICAL FIELD
[0002] The present invention relates to a metal membrane with
orthogonally isotropic behavior having corrugations to be
expandable and thus suitable for storing cryogenic fluids such as
liquefied natural gas.
BACKGROUND
[0003] Liquefied natural gas ("LNG") is generally a cryogenic
liquid having a boiling point of approximately -162.degree. C.
under atmospheric pressure and stored in a multiple structured
storage tank for thermal isolation.
[0004] This LNG storage tank has a metal membrane inner tank and a
thermal isolation layer surrounding the inner tank to store
ultra-low-temperature LNG safely by preventing the loss of
evaporation.
[0005] Since metal membranes are in direct contact with the
ultra-low-temperature LNG, they must be made of metallic materials
having excellent resistance to brittle fracture in a low
temperature to respond against stress changes and have structure to
facilitate expansion and contraction in response to heat and load.
Each metal membrane is thus welded with the common edge of another
adjacent metal membrane to keep a cargo air-tight.
[0006] Conventional metal membranes of a LNG storage tank are
described below.
[0007] FIG. 1 and FIG. 2 are perspective views illustrating metal
membranes of a LNG storage tank according to a conventional
embodiment. U.S. Pat. No. 3,118,523 discloses "connecting element
for expansion joints" in which corrugations 1, 2 of a metal sheet
are connected with a top or cap portion 3 of square form at the
intersection of two corrugations.
[0008] FIG. 3 is a perspective view illustrating a metal membrane
of a LNG storage tank according to another conventional embodiment.
U.S. Pat. No. 3,302,359 discloses "corrugated sheet-like yieldable
wall element and vessels or tanks made thereof" in which an
intersection area 203 is formed at the intersection of corrugations
202a, 202b of a metal sheet 201.
[0009] FIG. 4 is a perspective view illustrating a metal membrane
of a LNG storage tank according to further another conventional
embodiment. As shown in FIG. 4, a metal membrane 10 of a LNG
storage tank has longitudinal and transverse expandable
corrugations 11, 12 not to cause thermal stress due to extreme
thermal deviation of about 200.degree. C.
[0010] In addition to the metal membranes of a LNG storage tank
described above, expandable metal membranes have been developed
mainly for thermal isolation tanks of LNG carrier. JP Patent No.
Sho 50-21008 discloses a membrane having Y-shaped intersection in
which repeating hexagonal corrugations are formed with 120.degree.
. JP Patent No. Sho 60-14959 discloses a membrane having triangular
corrugations and trapezoid corrugations crossing to the triangular
corrugations. JP Patent No. Sho 60-32079 discloses a membrane
expansion structure in which corrugations protruded on the surface
are divergently arranged from at least one concentration
section.
[0011] Further, KR Patent Application No. 1994-11802 discloses
"membrane structure for LNG storage tank and method for
manufacturing the same" in which the membrane structure includes 4
corrugations forming a cross shape and a ring knot. KR Patent
Application No. 1994-11804 discloses "membrane structure for LNG
storage tank" including four legs each of which includes a
cross-sectioned insulating corrugation portion, a body portion
having indented joints, an expanded portion indented towards the
board member from an end portion of the body portion, and a valley
portion.
[0012] In addition, various metal membranes have been disclosed in
KR Patent Application No. 2003-83849 titled "Membrane Metal Panel
of Insulated Cargo Tanks of LNG Carrier", KR Patent Application No.
2003-83850 titled "Membrane Metal Panel of Insulated Cargo Tanks of
LNG Carrier", KR Patent Application No. 2003-92250 titled "Membrane
Metal Panel of Liquefied Natural Gas Storage Tanks", KR Patent
Application No. 2004-6648 titled "Membrane Metal Panel With Flat
Welding Joint Part for Insulated Cargo Tank of LNG Carrier", KR
Patent Application No. 2004-9306 titled "Membrane Metal Panel of an
Insulated Cargo Tank Storing a Low Temperature Liquid That Has Flat
Welding Joint", KR Patent Application No. 2004-21526 titled
"Membrane Metal Panel of LNG Storage Tanks", and U.S. Pat. No.
3,324,621 titled "Cold Liquid Container and Elements for Use in
Same".
[0013] As described above, the metal membrane of a LNG storage tank
according to a conventional embodiment in FIG. 4 has different
height of each intersection where corrugations intersect each
other. Plane rigidity in the longitudinal direction is thus 2 or
more times higher than that in the transverse direction due to
asymmetric shape at the intersections, which further causes
different thermal stress according to the direction at a low
temperature. Because the height of the corrugations in the
transverse direction is relatively higher than that in the
longitudinal direction at the intersection, they are expected to
collapse easily for pressure such as sloshing and the like.
[0014] The plane rigidity of a metal membrane is influenced by the
rigidity of bidirectional bent intersections rather than shape of
corrugations themselves. Even though since height and width of
transverse direction corrugations are higher, plane rigidity in the
longitudinal direction should be less than that in the transverse
direction in rigidity of conventional metal membranes according to
the direction, plane rigidity in the transverse direction is less.
This is caused by the shape of intersections of the conventional
metal membrane since more corrugations in the cross direction to
transverse direction corrugations are formed. A problem, that
thermal stress of a metal membrane in the transverse direction is
thus significantly higher than that in the longitudinal direction
during contraction at a low temperature, is created.
[0015] The conventional inventions, including the inventions as
described in FIG. 1, FIG. 2 and FIG. 3, have tried to obtain a
symmetric shape in cross-directions or simplify welding lines to
resolve such problems. However, the problem of the plane rigidity,
which influences degree of thermal stress at an ultra low
temperature, has not been solved. There has been no introduction of
intersection structures efficiently expandable bidirectionally to
reduce the plane rigidity. Therefore, even though corrugations are
formed, it may not reduce the plane rigidity but cause significant
thermal stress if straight lines connecting both corners of a unit
panel along the surface of corrugations are formed or if straight
welding joint is formed.
[0016] Since there is no membrane structure clamping using a
clamping unit of an automatic welding robot, which is a major
consideration in manufacturing a storage tank using a metal
membrane as shown in FIG. 1, FIG. 2 and FIG. 3, problems are still
when applied in actual field.
[0017] The present invention is therefore provided to resolve such
problems as described above.
SUMMARY
[0018] An aspect of the present invention is to provide an
expandable metal membrane having orthogonally isotropic behavior in
a metal membrane of a low-temperature-fluid storage tank having
longitudinal and transverse corrugations which intersect each
other, wherein a bidirectional expandable member connected to each
corrugation is formed so that the bidirectional expandable member
is longitudinally and transversely expandable in the intersection
of the corrugations, the bidirectional expandable member is
protruded in a pyramid shape, and first caved grooves are formed at
corners where lateral faces of the bidirectional expandable member
are connected, second caved grooves are formed on a top part of the
portion connected with the bidirectional expandable member in the
corrugations, and clamping parts protruded to be clamped by a
clamping unit are formed at both ends of the corrugations connected
to the bidirectional expandable member.
[0019] Another aspect of the present invention is to provide an
expandable metal membrane having orthogonally isotropic behavior in
a metal membrane of a low-temperature-fluid storage tank having
longitudinal and transverse corrugations which intersect each
other, wherein a bidirectional expandable member connected to each
corrugation is formed so that the bidirectional expandable member
is longitudinally and transversely expandable in the intersection
of the corrugations, the bidirectional expandable member is
protruded in a dome shape, a neck part is formed at the portion
where the bidirectional expandable member is connected in the
corrugations, and clamping parts indented to be clamped by a
clamping unit are disposed at either sides of the bidirectional
expandable member between portions where the bidirectional
expandable member and the corrugation are connected.
[0020] Still another aspect of the present invention is to provide
an expandable metal membrane having orthogonally isotropic behavior
in a metal membrane of a low-temperature-fluid storage tank having
longitudinal and transverse corrugations which intersect each
other, wherein a bidirectional expandable member, protruded in a
cross shape and connected to each corrugation between branching
parts of the cross shape, is formed so that the bidirectional
expandable member is longitudinally and transversely expandable at
an intersection of the corrugations, and clamping parts are formed
in such a way that the clamping parts are clamped by a clamping
unit at either lateral face of the branching parts by having the
bidirectional expandable member protrude over the corrugations.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0021] FIG. 1 and FIG. 2 are perspective views illustrating metal
membranes of a LNG storage tank according to an embodiment of the
conventional arts.
[0022] FIG. 3 is a perspective view illustrating a metal membrane
of a LNG storage tank according to an embodiment of the
conventional arts.
[0023] FIG. 4 is a perspective view illustrating a metal membrane
of a LNG storage tank according to another embodiment of the
conventional arts.
[0024] FIG. 5 is a perspective view illustrating a metal membrane
of a LNG storage tank according to a first embodiment of the
present invention.
[0025] FIG. 6 is a partially magnified sectional view illustrating
an expandable metal membrane with orthogonally isotropic behavior
according to a first embodiment of the present invention.
[0026] FIG. 7 illustrates a clamping part of an expandable metal
membrane with orthogonally isotropic behavior according to a first
embodiment of the present invention.
[0027] FIG. 8 is a perspective view illustrating an expandable
metal membrane with orthogonally isotropic behavior according to a
second embodiment of the present invention.
[0028] FIG. 9 is a partially magnified sectional view illustrating
an expandable metal membrane with orthogonally isotropic behavior
according to a second embodiment of the present invention.
[0029] FIG. 10 is a perspective view illustrating an expandable
metal membrane with orthogonally isotropic behavior according to a
third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Bent intersections determining the plane rigidity of a metal
membrane may be shaped like a pyramid, a dome or a cross to reduce
plane rigidity and, at the same time, equalize plane rigidity of
two intersecting directions so the metal membrane is easily clamped
by a clamping unit of a welding robot or a transfer device.
[0031] Hereinafter, certain embodiments of the present invention
will be described in detail with reference to the accompanying
drawings. Throughout the description of the present invention, when
describing a certain technology is determined to evade the point of
the present invention, the pertinent detailed description will be
omitted.
[0032] FIG. 5 is a perspective view illustrating a metal membrane
of a LNG storage tank according to a first embodiment of the
present invention and FIG. 6 is a partially magnified sectional
view illustrating an expandable metal membrane with orthogonally
isotropic behavior according to a first embodiment of the present
invention. As shown in FIGS. 5 and 6, an expandable metal membrane
with orthogonally isotropic behavior 100 according to a first
embodiment includes corrugations 120 and 130, formed in the
longitudinal direction and the transverse direction and
intersecting each other, on a panel 110 made of metal, and a
bidirectional expandable member 140 at the intersection of the
corrugations 120 and 130, in which the bidirectional expandable
member 140 is protruded and has a pyramid shape.
[0033] The corrugations 120 and 130 includes a first corrugation
120 and a second corrugation 130 whose cross sections form a fillet
with the flat part and intersect each other on the panel 110,
preferably orthogonally.
[0034] A plurality of the first corrugations 120 are formed to be
parallel with each other in the longitudinal direction on the panel
110 so that they are expandable in the transverse direction of the
panel 110.
[0035] A plurality of the second corrugations 130 are formed to be
parallel with each other in the transverse direction on the panel
110 so that they are expandable in the longitudinal direction of
the panel 110.
[0036] The bidirectional expandable member 140 is connected to each
of the front and back and the left and right of the first and the
second corrugations 120 and 130 at the intersection of the first
and the second corrugations 120 and 130. Four (4) sides 141 having
a pyramid shape are protruded upward like the first and the second
corrugations 120 and 130, and are connected to each of the first
and the second corrugations 120 and 130. The bidirectional
expandable member 140 is thus able to let the corrugations be
longitudinally and transversely expandable by changing the pyramid
shape.
[0037] The bidirectional expandable member 140 includes first caved
grooves 142 to provide expandability to the corners where the sides
141 are connected.
[0038] The first groove 142 may be clamped by a clamping unit of a
welding robot instead of a clamping part 150 which will be
described later, or a clamping unit of a transfer device which
moves the metal membrane 100 along a guide rail.
[0039] The corrugations 120 and 130 include second caved grooves
121 and 131, respectively, to provide expandability to the top part
of the portion connected with the bidirectional expandable member
140.
[0040] The bidirectional expandable member 140 may include the
clamping part 150 to couple a clamping unit of a welding robot or a
clamping unit of a guide rail to the membrane.
[0041] The clamping part 150 is formed to be protruded at both ends
of the corrugations 120 and 130 to which the bidirectional
expandable member 140 is connected to be clamped by a clamping
unit. As shown in FIG. 5, the clamping unit is provided to be
clamped in the "A" and "B" directions.
[0042] The upper part of the clamping part 150 is more protruded
than the bottom part to prevent a breakaway when a clamping unit is
clamped as shown in FIG. 7.
[0043] The expandable metal membrane with orthogonally isotropic
behavior 100 according to a first embodiment of the present
invention allows longitudinal and transverse expansion at
intersection of the corrugations 120 and 130 by providing the
expandable pyramid-shaped bidirectional expandable member 140 at
the intersection of the corrugations 120 and 130 so that it reduces
plane rigidity throughout the panel 110. Expandability in the
longitudinal direction and the transverse direction of the panel
110 is kept by connecting the corrugations 120 and 130 to the
bidirectional expandable member 140 to maintain continuity.
Expandability is even improved and plane rigidity is significantly
reduced by providing the first grooves 121 and 131 each formed at
the first and the second corrugations 120 and 130, respectively,
and the second grooves 142 formed at the bidirectional expandable
member 140.
[0044] Further, a clamping unit of a welding robot or a transfer
device may clamp the clamping part 150, which are formed at the
both ends of the corrugations 120 and 130 where the bidirectional
expandable member 140 is connected, at the "A" and "B" direction as
shown in FIG. 5.
[0045] FIG. 8 is a perspective view illustrating an expandable
metal membrane with orthogonally isotropic behavior according to a
second embodiment of the present invention and FIG. 9 is a
partially magnified sectional view illustrating an expandable metal
membrane with orthogonally isotropic behavior according to a second
embodiment of the present invention. As shown in FIG. 8 and FIG. 9,
an expandable metal membrane with orthogonally isotropic behavior
200 according to a second embodiment includes corrugations 220 and
230 formed in the longitudinal direction and the transverse
direction intersecting each other on a panel 210 made of metal, a
bidirectional expandable member 240 at the intersection of the
corrugations 220 and 230, in which the bidirectional expandable
member 240 protrudes and is a dome shape.
[0046] The corrugations 220 and 230 are composed with first
corrugations 220 formed in the longitudinal direction and second
corrugations 230 formed in the transverse direction as described in
the first embodiment.
[0047] The bidirectional expandable member 240 is connected to each
of the front and back and the left and right of the first and the
second corrugations 220 and 230 at the intersection of the first
and the second corrugations 220 and 230. The bidirectional
expandable member 240 is protruded upward and has a hemispherical
dome shape having an appropriate radius. Accordingly, the
bidirectional expandable member 240 allows the corrugations 220 and
230 to be expandable in the longitudinal direction and the
transverse direction by having a dome shape to be flexible toward
any direction.
[0048] The corrugations 220 and 230 include neck parts 221 and 231
which are narrower compared to other portions, at the portion where
they are connected to the bidirectional expandable member 240 so
that the corrugations 220 and 230 are easily expandable to the
longitudinal direction and the transverse direction with the
bidirectional expandable member 240 due to the expandability of the
neck parts 221 and 231 provided by their folding and
flattening.
[0049] The membrane may include clamping parts 250 at both sides of
the bidirectional expandable member 240 to couple a clamping unit
of a welding robot or a clamping unit of a guide rail to the
membrane.
[0050] The clamping parts 250 are positioned to face each other
between the portions connected to the corrugations 220 and 230 as
shown in FIG. 8 and include indented part 251 for the clamping unit
to clamp to the "A" and "B" directions.
[0051] The clamping unit may have a shape corresponding to the
shape of the clamping part 250 to clamp the clamping part 250
easily.
[0052] As shown in FIG. 8, the expandable metal membrane with
orthogonally isotropic behavior 200 according to a second
embodiment of the present invention allows longitudinal and
transverse expansion at intersection of the corrugations 220 and
230 by providing the dome-shaped bidirectional expandable member
240 expandable at the intersection of the corrugations 220 and 230
so that it reduces plane rigidity throughout the panel 210.
Expandability in the longitudinal direction and the transverse
direction of the panel 210 is kept by connecting the corrugations
220 and 230 to the bidirectional expandable member 240 to maintain
continuity. Expandability is even improved and plane rigidity is
significantly reduced by providing the neck parts 221 and 231 of
the corrugations 220 and 230.
[0053] Further, a clamping unit of a welding robot or a transfer
device may clamp the indented part 251, which are formed at the
both sides of the bidirectional expandable member 240, at "A" and
"B" directions as shown in FIG. 8.
[0054] FIG. 10 is a perspective view illustrating an expandable
metal membrane having orthogonally isotropic behavior according to
a third embodiment of the present invention. As shown in FIG. 10,
an expandable metal membrane having orthogonally isotropic behavior
300 according to a third embodiment includes a plurality of
corrugations 320 and 330 formed in the longitudinal direction and
the transverse direction on a panel 310 made of metal, a
bidirectional expandable member 340 at the intersection of the
corrugations 320 and 330, in which the bidirectional expandable
member 340 is protruded and has a cross shape and clamping parts
350 formed at both sides of the branching part 341 of the cross
shape to couple a clamping unit of a welding robot or a clamping
unit of a guide rail to a membrane.
[0055] The corrugations 320 and 330 are composed of first
corrugations 320 formed in the longitudinal direction and second
corrugations 330 formed in the transverse direction as described in
the previous embodiments.
[0056] The bidirectional expandable member 340 is protruded as a
cross shape at the intersection of the first and the second
corrugations 320 and 330 and each of the first and the second
corrugations 320 and 330 is connected smoothly to a branching part
341. When the first and the second corrugations 320 and 330
intersect each other, the branching part 341 forms a 45.degree.
with the first and the second corrugations 320 and 330. Expansion
in the longitudinal direction and the transverse direction is
provided by the deformation of the cross shape.
[0057] The side shape of the branching part 341 is a fan shape and
each of the first and the second corrugations 320 and 330 is
positioned near the vertex of the fan shape to be easily
transformable against compression and tension.
[0058] The membrane may include clamping parts 350 at the branching
part 341 of the bidirectional expandable member 340 to be clamped
by a clamping unit of a welding robot or a clamping part of a
transfer device which moves a metal membrane 300 along a guide
rail.
[0059] The clamping parts 350 are formed at both sides of the
branching part 341 by forming the bidirectional expandable member
340 to be more protruded than the corrugations 320 and 330 as shown
in FIG. 10 and are formed for the clamping unit to clamp to the "A"
and "B" directions.
[0060] The expandable metal membrane with orthogonally isotropic
behavior 300 according to a third embodiment of the present
invention allows longitudinal and transverse expansion at
intersection of the corrugations 320 and 330 by providing the
cross-shaped bidirectional expandable member 340 expandable at the
intersection of the corrugations 320 and 330 so that it reduces
plane rigidity throughout the panel 310. Expandability in the
longitudinal direction and the transverse direction of the panel
310 is kept by connecting the corrugations 320 and 330 to the
bidirectional expandable member 340 to maintain continuity.
Deformation according to compression and tension is easily made,
expandability is even improved, and plane rigidity is significantly
reduced by providing the fan shaped side of the branching part 341
of the bidirectional expandable member 340 having the same radii
from the arc-shaped edges to the corrugations 320 and 330.
[0061] Further, a clamping unit of a welding robot or a transfer
device may clamp the clamping part 350, which are formed at the
both sides of the branching part 341 of the bidirectional
expandable member 340, at "A" and "B" directions as shown in FIG.
10.
[0062] As described above, each metal membrane is welded into a
unit panel and the edge of each metal membrane is welded with the
common edge of another adjacent metal membrane to keep a cargo
warehouse air-tight, and ultra-low-temperature LNG is stored inside
the cargo warehouse, so when the metal membrane contracts due to
thermal deviation, the present invention reduces plane rigidity
and, at the same time, equalizes plane rigidity of two intersecting
directions.
[0063] While it has been described with reference to particular
embodiments, it is to be appreciated that various changes and
modifications may be made by those skilled in the art without
departing from the spirit and scope of the embodiment herein, as
defined by the appended claims and their equivalents. As such, many
embodiments other than that set forth above can be found in the
appended claims.
* * * * *