JPS6098298A - Bent membrane corrugation - Google Patents

Abstract

PURPOSE:To remarkably reduce the length of weld by weldingly closing the gap between bent and rising parts, which are opposite to each other, only at the end parts, of a corrugation which is formed by bending a membrane in an inverted U-shape. CONSTITUTION:A membrane 1 is bent and formed into an inverted U-shape, forming a corrugation 2, in which the gap between bent and rising parts 2a, 2a, which are opposite to each other, is welded (w) and closed only at its end parts. Although the top part of the corrugation 2 is subjected to repeated stress due to the repetition of cooling and rising in temperature of a storage tank, the corrugation 2, which is bent and formed into an inverted U-shape, can reduce the stress concentration by force of its configuration.

Description

DETAILED DESCRIPTION OF THE INVENTION In a membrane type cryogenic liquid storage tank, corrugations are usually provided in the membrane in order to absorb excessive thermal strain caused by thermal contraction of the membrane.

When molding this corrugation, please refer to Figures 1 and 2.
L at each end of the opposing membrane (α) as shown in the figure.
Bend it into the shape to make the flange part (h), put the opposing flange parts (b) and (A) together, and weld the ends (
W) There is a way to close it.

This forming method is advantageous in that it does not require sophisticated processing equipment, but on the other hand, as the welded part becomes longer, the inspection length also becomes proportionally longer, which requires a great deal of effort to ensure product reliability. There is.

The present invention was proposed to solve these problems, and only at the terminal end of the corrugation formed by bending the membrane into an inverted U-shape, the opposing bent upright pieces are welded and closed. This relates to a folded membrane corrugation characterized by the following characteristics.

According to the present invention, the membrane is bent into an inverted U-shape to form a corrugation, and only the terminal ends of the corrugation are welded and closed between the opposing bent pieces, so the weld length is significantly reduced. reduced costs and improved reliability. In addition, the top of the corrugation is used to cool the storage tank.
When subjected to repeated stress due to thermal contraction and expansion due to repeated temperature increases, the stress concentration in the corrugations bent into an inverted U-shape is reduced, improving fatigue strength, and as a result, the service life of the corrugations is shortened. extends. In addition, in the present invention, a welded part is provided at the terminal end to make molding easier and cheaper, but since this part does not open or close due to heat shrinkage, there is no problem with strength, and the present invention The heat shrinkage function of the corrugation according to the invention is the same as that of the conventional method, and the proven corrugation arrangement pattern can be used as is.

The present invention will be described below with reference to the illustrated embodiments.

In FIG. 3, the membrane (1) is bent into an inverted U-shape to form corrugations (2).

Only at the terminal end of the corrugation (2), the opposing bent upright pieces (2α) (2α) are welded (W) and closed.

The connection length between the bent part and the welded part at the end of the corrugation (2) can be determined by inserting filler metal (3) as shown in Figures 5 and 6, or by inserting filler metal (3) as shown in (4). Squeeze and then press the rising piece (2αX2a
) are welded (W) and closed.

The corrugations shaped in this way do not intersect with each other, and the terminal end of one corrugation is placed as close as possible to the other corrugation.

Figure 7 shows a basic checkered pattern arrangement method as an example of corrugation arrangement, and is shown by a solid line (2A).
is the corrugation position before heat shrinkage, shown by the dotted line (2B)
shows the corrugation position after heat shrinkage, (2C) shows the terminal end of the corrugation, and (2D) shows the opening of the corrugation base opened by heat shrinkage. Further, (5) shows a state in which the membrane flat plate portions contract due to heat and, at the same time, adjacent flat plate portions invert each other.

Furthermore, Figure 8 shows a membrane (2) containing corrugations (2).
A part of 1) is shown three-dimensionally.

The top of the corrugation is subjected to repeated stress due to thermal contraction and thermal expansion due to repeated cooling and temperature rise of the storage tank, but in the illustrated embodiment, the corrugation (2i is
Since it is bent into a letter shape, stress concentration is reduced due to the shape and fatigue strength is improved.

As a result, the service life of the corrugations (2), which open and close through thermal contraction and expansion, is extended, and on the other hand, if the same service life as before is to be ensured, the spacing between the corrugations can be increased.

The spacing between the corrugations is determined by the temperature of the storage body, the amount of opening and closing of the corrugations, which is determined in proportion to the spacing between the corrugations, and the cyclic fatigue strength of the corrugations.

For example, in the example shown in FIG. 7, two corrugations are arranged in parallel because it is necessary to set the opening/closing amount of the corrugation to μ for the corrugation arrangement interval α, but according to the illustrated embodiment, the corrugation interval can be changed. Without, 1
It can also be arranged in rows.

As a result, it is possible to use the current corrugation arrangement Noreen, which has a proven track record, as is, and the Al of t:
There is no need to research and develop the entire menzolene system again.

In addition, the corrugation (2) is provided with welded parts at both ends in order to make molding easier and at a lower cost, but as shown in Figure 7, these parts do not open or close due to heat shrinkage. No strength problems occur.

Further, the bent corrugation (2) does not undergo compression due to hydraulic pressure or the like due to its shape, and the stability as a membrane is ensured in the same manner as in the conventional method.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a conventional membrane corrugation, FIG. 2 is a slope view thereof, FIG. 3 is a vertical sectional view showing an embodiment of the folded membrane corrugation according to the present invention, and FIG. 4 is a slope view thereof. 5 and 6 are respectively perspective views of the terminal ends of the corrugations, FIG. 7 is a plan view showing the arrangement of the corrugations, and FIG. 8 is a perspective view of the membrane in which two corrugations are arranged side by side. (1)...Membrane, (2+...Corrugation, (2α)...Folded rising piece, (3)...Filler metal, (4)...Crushing part Figure 7

Claims (1)

[Claims] A folded membrane corrugation characterized in that only the terminal end of the corrugation formed by bending and forming a membrane into an inverted U-shape is formed by welding and closing opposing folded rising pieces.