JP5405670B2 - Floating body - Google Patents

Description

The present invention relates to a floating body used for a floating roof of a floating roof type storage tank for storing petroleum products such as crude oil and gasoline.
This application claims priority on January 14, 2011 based on Japanese Patent Application No. 2011-005735 for which it applied to Japan, and uses the content here.

  A floating roof type storage tank is generally known as a tank for storing a flammable liquid such as oil. This type of floating roof type storage tank has a structure in which a floating roof formed of a steel plate or the like is floated on this liquid so as to cover the liquid level of flammable liquid such as oil stored in the tank. . The floating roof has a pontoon having a hollow (floating chamber) inside, and the entire floating roof floats in a liquid by the buoyancy of the pontoon. The floating roof also moves up and down following the change in the liquid level due to the increase or decrease of the liquid stored in the tank, and the state where the liquid level of the stored liquid is always covered with the floating roof is maintained.

  By the way, in such a floating roof type storage tank, the pontoon of the floating roof formed of a steel plate may be damaged from the welded portion or the like due to vibration caused by sloshing (liquid level vibration) or the like. For example, in Patent Document 1 and Patent Document 2, even if the pontoon is damaged in this way and the liquid in the tank enters the pontoon, in order to maintain an appropriate buoyancy, It has been proposed to accommodate (floating). By accommodating the floating body in the pontoon in this way, even if liquid enters the pontoon, the entire floating roof is maintained in a state of floating in the liquid in the tank by the buoyancy of the floating body itself.

Japanese National Publication No. 58-24867 Japanese Unexamined Patent Publication No. 2006-143291

  In floating roof tanks that store oil, etc., even if a fire breaks out, the floating roof stays on the liquid level stored in the tank for the time required for extinguishing the fire (for example, about 48 hours). It is required that the floating state can be maintained. However, since the floating body used for the conventional floating roof is formed with bags, such as rubber and resin, it is inferior in fire resistance and cannot endure the high temperature at the time of a fire. For this reason, if the pontoon is damaged in the event of a tank fire, the floating roof cannot be kept floating on the liquid level of the liquid stored in the tank.

  Further, since the conventional floating body has a sealed structure, there is a risk that the internal gas expands due to heating during a fire and breaks, and further, there is a risk that the gas will shrink due to cooling after the fire is extinguished. For this reason, the conventional floating body may not be able to maintain an appropriate buoyancy due to a temperature change during a fire.

  This invention is made | formed in view of such a situation, and it aims at provision of the floating body which is excellent in fire resistance and can maintain appropriate buoyancy even if there is a temperature change of surrounding environment.

The present invention employs the following aspects in order to solve the above-described problems and achieve the object.
(1) One aspect of the present invention is a floating body that is accommodated in a floating chamber of a floating roof of a floating roof tank, and is made of a metal body that has an opening at least at one location and has an internal space. If, having an edge formed by spirally formed, covering the opening by the edge is engaged is seamed with respect to the opening, and receives from the periphery of the floating body external pressure Or a metal lid attached so as to move toward and away from the main body by internal pressure received from the inside of the floating body, and between the opening and the edge, The external space and the internal space are communicated with each other, allowing the approaching and separating operation between the main body and the lid without interposing a sealing material, and the lid is separated from the main body by the internal pressure. a first gap is formed when The first contact portion for blocking said first gap when approaching the lid is most to the body by the external pressure; is provided.
(2) In the floating body according to (1), the main body forms a cylinder having a pair of the openings; the lid body is fastened to each of the openings of the cylinder. The first gap is provided between one of the lids and one of the openings to which the one lid is attached, and between the other of the lids and the other of the openings. And the first contact portion is provided; a configuration may be employed.
(3) The floating body according to (1) or (2) may be a metal square can in which the cylindrical body is square and each lid body is square.
(4) In the floating body according to any one of (1) to (3), when the portion of the tightening is viewed in a cross section including the approaching / separating direction, the opening of the main body You may employ | adopt the structure which the said edge of the said cover body has latched.
(5) In the floating body according to any one of (1) to (4), the opening and the edge, wherein the first contact portion is formed in an annular shape along the opening. The line contact part between parts may be sufficient.
(6) In the floating body according to any one of (1) to (5) above, the number of windings may be two or more.
(7) In the case of the floating body according to (6) above, when the wound portion between the opening and the edge is viewed in a cross section along the approaching / separating direction, the first gap is A plurality of linear gap portions along the approaching / separating direction, and a folded back gap portion that folds the linear gap portions together to connect each other; When viewed in a cross section that intersects the approaching / separating direction at an intermediate position, the average gap size of these linear gap portions is in the range of 100 μm or more and 175 μm or less; the configuration may be adopted.
(8) In the floating body according to any one of (1) to (7), the thickness of the main body is in the range of 0.20 mm to 0.32 mm; the thickness of the lid is 0 Within the range of 20 mm to 0.32 mm; configuration may be employed.
(9) In the floating body according to any one of (1) to (8), the main body is formed by bending a rectangular metal plate into a cylindrical shape and joining two sides facing each other; The joint is wound and the two opposing sides are engaged , and the outer and inner pressures are wound so as to relatively move and move apart between the two sides. When the internal space and the external space of the main body are communicated between two sides and the approaching / separating operation between the two sides is allowed and the two sides are relatively separated by the internal pressure And a second abutting portion that blocks the second gap when the two sides are closest to each other by the external pressure. May be.
(10) In the case of the floating body described in (9) above, the number of windings between the two sides may be two or more.
(11) In the case of the floating body according to (9) or (10) above, the second contact portion may be a line contact portion between the two sides.
(12) Another aspect of the present invention is a floating body accommodated in a floating chamber of a floating roof of a floating roof type tank, and a rectangular metal plate is folded into a cylindrical shape and two opposite sides are joined to each other. A main body; a lid fixed to cover the opening of the main body, the joint being wound and the two opposing sides engaged , and the periphery of the floating body Between the internal space and the external space of the main body between the two sides, which are wound so as to be relatively close to and away from each other by an external pressure received from the inside or an internal pressure received from the inside of the floating body. the made to communicate with, a sealing material without interposing the well as permit the approach separating operation between the two sides, a third gap and said two sides are formed when relatively spaced apart by the internal pressure, the when the two sides to each other is closest to each other by external pressure A third contact portion for blocking said third gap; are provided.
(13) In the case of the floating body according to (12), the number of windings between the two sides may be two or more.
(14) In the case of the floating body according to (12) or (13) above, the third contact portion may be a line contact portion between the two sides.

According to the floating body according to the aspect described in (1) of the present invention, it is excellent in fire resistance and can maintain an appropriate buoyancy even if there is a temperature change in the surrounding environment.
When this is demonstrated, since the floating body of this aspect is metal, it is excellent in fire resistance so that it cannot compare with the conventionally proposed resin floating body. It should be noted that the problem of the present application cannot be solved simply by making the conventionally proposed resin floating body simply made of metal.
That is, assuming a metal floating body that is simply sealed with air inside to obtain buoyancy, on the other hand, when heated by a flame such as when a fire occurs, the air sealed inside It cannot be forbidden that the internal pressure rises due to heating. Moreover, in the case of a metal floating body in which the degree of deformation when subjected to internal pressure is limited compared to that made of resin, there is a risk of damage if the internal pressure exceeds an allowable value.
On the other hand, in the floating body of this aspect, since the first gap that allows the approaching and separating operation between the main body and the lid body is provided, when an excessive increase in internal pressure occurs in the internal space, this internal pressure is used. The lid can be slightly separated from the main body so as to ensure the first gap. Then, excessive internal pressure in the internal space of the floating body can be released toward the external space via the first gap. In addition, this adjustment function is achieved only by tightening without using extra parts such as a safety valve, so it can be manufactured at low cost and contributes to the weight reduction of the floating body itself. doing.
Further, in the floating body of this aspect, even if there is no excessive increase in internal pressure due to heating when the liquid has entered the floating chamber, the liquid now acts as an external pressure on the floating body. Then, the lid body that has been subjected to the external pressure performs a slight approach operation as if pressed against the main body, and as a result, the first gap is automatically blocked at the first contact portion. Therefore, since air is sealed in the internal space of the floating body, sufficient buoyancy can be obtained.

  According to the floating roof using the floating body of the above aspect, even if there is a required temperature change in the floating chamber, there is less deformation such as expansion and contraction, and appropriate buoyancy can be achieved. A plurality of floating bodies that can be maintained are accommodated. Therefore, even if the floating chamber is damaged due to a fire or the like, the floating roof can be maintained in the liquid stored in the floating roof type tank by the buoyancy of the floating body.

It is a longitudinal cross-sectional view which shows the floating roof and the floating roof-type tank which accommodated the floating body which concerns on one Embodiment of this invention in the pontoon. It is a longitudinal cross-sectional view which shows the state in which the liquid store stored in the floating roof type tank shown in FIG. 1 infiltrated into the pontoon of the floating roof. It is a disassembled perspective view which shows the main body and lid which comprise the floating body which concerns on the same embodiment. It is a front view of the floating body. It is a figure which shows the opening part of the cylinder before winding of the floating body, and the edge part of a cover body, Comprising: It is sectional drawing to which the part corresponded to the A section of FIG. 3B was expanded. It is a figure which shows the opening part of the cylinder after winding of the floating body, and the edge part of a cover body, Comprising: It is an expanded sectional view of the A section of FIG. 3B. It is a figure which shows the shape of the opening part of the cylinder after winding of the floating body, Comprising: It is an expanded sectional view of the A section of FIG. 3B. It is a figure which shows the shape of the edge part of the cover body after winding of the floating body, Comprising: It is an expanded sectional view of the A section of FIG. 3B. It is a figure which shows the clearance gap which connects between the internal space and external space of a floating body, Comprising: It is an expanded sectional view of the A section of FIG. 3B. It is a figure which shows the state of the clearance gap when an external pressure is applied to a cylinder, Comprising: It is sectional drawing to which the part corresponded to the A section of FIG. 3B was expanded. It is a figure which shows the state of the clearance gap when an internal pressure is applied to a cylinder, Comprising: It is sectional drawing to which the part corresponded to the A section of FIG. 3B was expanded. It is a top view before attaching a cover body to the cylinder of the floating body. It is a figure which shows the state of the clearance gap when an external pressure is applied to a cylinder, Comprising: It is the plane sectional view which expanded the part corresponded to the B section of FIG. 7A. It is a figure which shows the state of the clearance gap when an internal pressure is applied to a cylinder, Comprising: It is the plane sectional view which expanded the part corresponded to the B section of FIG. 7A.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited only to the configurations of the following embodiments, and various modifications can be made without departing from the spirit of the present invention. Is possible. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for the sake of convenience. Not necessarily.

[First Embodiment]
FIG. 1 is a longitudinal sectional view showing a floating roof 200 in which the floating body 10 according to the first embodiment of the present invention is accommodated in a pontoon 220 and a floating roof type tank 100. In FIG. 1, reference sign CL indicates the central axis of the floating roof tank 100.

As shown in FIG. 1, a liquid storage product OL such as petroleum products is stored in a bottomed cylindrical floating roof tank 100 of the present embodiment, and floats on the liquid surface of the liquid storage product OL. The roof 200 is floating.
The floating roof 200 is formed of a steel plate, and is formed in a ring shape along the peripheral edge of the upper surface of the roof main body 210, and when viewed from the longitudinal section, the floating roof 200 is outward from the center of the ring. And a pontoon 220 that gradually increases in height.
The pontoon 220 is arranged so as to be coaxial with the outer wall 220a, which is a cylindrical outer wall 220a that is welded and fixed to the roof main body 210 so as to stand vertically upward from the peripheral edge thereof. A cylindrical inner wall 220b welded and fixed so as to stand vertically above the upper surface and a space between the outer wall 220a and the inner wall 220b are welded and fixed to the upper edges of the outer wall 220a and the inner wall 220b. A ring-shaped upper wall 220c. The pontoon 220 has a floating chamber E that is a ring-shaped cavity formed therein, and buoyancy can be generated by the air confined in the floating chamber E. Therefore, due to the buoyancy of the pontoon 220, the entire floating roof 200 floats over the upper surface of the liquid storage product OL stored in the floating roof tank 100.

  A predetermined gap G is provided between the outer peripheral surface 222 of the pontoon 220 and the inner peripheral surface 101 of the floating roof tank 100. A ring-shaped seal 221 is provided so as to be sandwiched in the gap G, and the upper opening of the floating roof tank 100 is sealed by filling the gap G. The seal 221 has a structure in which, for example, a cover sheet such as nitrile rubber (NBR) or fluorine rubber is formed in a floating ring shape and fixed to the outer peripheral surface 222 of the floating roof 200 (pontoon 220). The cover sheet has a compressed urethane foam.

  A large number of floating bodies 10 are accommodated in the floating chamber E of the pontoon 220. As these floating bodies 10, 18 liter cans made of metal and having a square shape (cuboid shape) are employed in the present embodiment. Such rectangular floating bodies 10 are accommodated in the floating chamber E of the pontoon 220 in a state where a plurality of rows of the floating bodies 10 are arranged and stacked in a plurality of stages. Thus, by adopting a square shape as the floating body 10 and stacking without gaps, a large number of floating bodies 10 can be accommodated in the floating chamber E with little spatial loss. As a result, the buoyancy of the floating roof 200 can be sufficiently secured even when the liquid storage product OL enters the floating chamber E.

Each floating body 10 is moved into and out of the floating chamber E from a manhole 223 formed on, for example, the upper wall 220c of the pontoon 220, so that the floating body E can be moved into and out of the floating chamber E for installation or maintenance. It is possible to take out. When installing the floating bodies 10 in the floating chamber E of the pontoon 220, they may be simply stacked and may be bundled together so that the arrangement does not collapse. Furthermore, each floating body 10 after being bound may be fixed to an inner wall such as a bottom wall in the floating chamber E. However, since these bundling and fixing are not indispensable for exerting the buoyancy of the floating body 10, the present embodiment illustrates a configuration in which these bundling and fixing are not performed.
A large number of floating bodies 10 are accommodated in the floating chamber E of the pontoon 220. However, since the floating body 10 itself is hollow and lightweight, the buoyancy of the pontoon 220 as a whole can be maintained. The specific structure of the floating body 10 will be described later.

  FIG. 2 shows that the seal 221 is damaged and lost due to vibration caused by sloshing (liquid level vibration) or the like in the floating roof tank 100 shown in FIG. 4 is a longitudinal sectional view showing a state in which a liquid storage product OL has entered a floating chamber E. FIG.

  As shown in FIG. 2, when the liquid storage OL enters the pontoon 220 until the liquid level So of the liquid storage OL in the floating roof tank 100 and the liquid level Si in the pontoon 220 become substantially the same position. In the pontoon 220, a large number of floating bodies 10 that sink into the liquid storage OL try to float all at once due to their buoyancy. A large number of floating bodies 10 floating in the liquid reservoir OL that has entered the pontoon 220 hit the lower surface of the upper wall 220c of the pontoon 220 and support it from below. As a result, the weight of the floating roof 200 can be supported by the buoyancy of each floating body 10, so that the floating roof 200 remains floating in the liquid storage OL even when the liquid storage OL enters the pontoon 220. it can. That is, even if the liquid storage product OL enters the pontoon 220, it is possible to leave the entire surface of the liquid storage product OL covered with the floating roof 200 except for the gap G.

  Furthermore, when a fire occurs and the liquid storage product OL is ignited with the liquid storage product OL entering the pontoon 220 as described above, the air in the floating chamber E is heated to a high temperature. As a result, the floating bodies 10 in the pontoon 220 are heated from the surroundings by the high-temperature air. In this case, due to the fire resistance of the floating body 10 itself made of metal, each floating body 10 is maintained in buoyancy without being damaged such as melting. As a result, even if a fire occurs, the floating roof 200 as a whole can be kept floating in the liquid storage product OL stored in the floating roof tank 100.

  As described above, the floating roof 200 is stored in the floating roof tank 100 even if the pontoon 220 is damaged due to sloshing or the like and the liquid storage OL enters the floating chamber E. It is required to float while covering the upper surface of the OL. Further, even if a fire occurs in this state, the floating roof 200 is required to float over the liquid level of the liquid storage product OL stored in the floating roof tank 100. In order to satisfy these requirements, the floating body 10 itself accommodated in the floating chamber E of the pontoon 220 is required to satisfy both airtightness and fire resistance.

Then, the detailed structure of the floating body 10 of this embodiment is demonstrated below.
As shown in FIG. 3A, the floating body 10 (metal can) is made of a thin metal plate (for example, tin-plated steel plate, tin-free steel, etc.), and is a rectangular tube body (metal) with curved portions formed at four corners. And a pair of lid plates 12 and 13 (metal end plates forming a lid), which are also made of a thin metal plate, are integrally combined.

  Each of the cover plates 12 and 13 has the same shape as each other, and has a quadrangular shape in which four corners are curved so as to match the shape of the opening portion 11x of the quadrangular cylinder 11. The lid plate 12 is joined so as to close the upper opening portion 11x of the rectangular cylindrical body 11, while the lid plate 13 is joined so as to close the lower opening portion 11x of the rectangular cylindrical body 11. In this way, by closing the upper and lower openings 11x of the rectangular cylinder 11 with the cover plates 12 and 13, air can be enclosed in the floating body 10.

  On each of the four side wall surfaces 11 y of the rectangular cylindrical body 11, a pair of longitudinal reinforcing beads 111 formed between the upper and lower openings 11 x and a pair extending in a direction intersecting the longitudinal reinforcing beads 111. The horizontal reinforcing beads 112 and the rectangular reinforcing portions 113 (commonly called picture frames) formed so as to be surrounded by the vertical reinforcing beads 111 and the horizontal reinforcing beads 112 are formed by pressing. Each of the four side wall surfaces 11y is reinforced by the formation of the vertical reinforcing beads 111, the horizontal reinforcing beads 112, and the rectangular reinforcing portions 113, and as a result, the entire rectangular cylindrical body 11 is structurally reinforced.

  The square cylinder 11 and the cover plate 12 are joined by, for example, winding shown in FIGS. 4A and 4B. In addition, although joining of the other cover board 13 is not demonstrated in particular, it is joined to the square cylinder 11 by the double winding fastening similar to the cover board 12. FIG.

  In the state before the tightening, as shown in FIG. 4A, in the state before the tightening, the one opening portion 11x of the rectangular cylindrical body 11 expands while gently curving from the inside toward the outside. A flange 11a is formed. Further, the edge portion 12x of the cover plate 12 has an inclined portion 12x1 that rises obliquely upward along the inner surface of the flange 11a, and a parallel portion 12x2 that continues to the inclined portion 12x1 and is substantially parallel to the central portion of the cover plate 12. And a curled portion 12x3 that is continuous with the parallel portion 12x2 and is bent in an arc shape so as to go from the upper side to the lower side of the flange 11a.

In addition, when forming the flange 11a in the opening part 11x of the square cylinder 11, the said longitudinal reinforcement bead 111 (refer FIG. 3A) in which a front-end | tip part reaches the opening part 11x which is an edge of the square cylinder 11 is the concave shape. Is processed so as to be returned to a flat surface at the tip of the flange 11a.
Then, the cover plate 12 is attached to one opening portion 11x (end edge portion) of the rectangular tube body 11 in a state in which the curled portion 12x3 of the edge portion 12x of the cover plate 12 is covered with the flange 11a of the rectangular tube body 11. Set. In this state, the double winding is performed in a state where the edge portion 12x including the curled portion 12x3 of the cover plate 12 and the flange 11a of the rectangular tube body 11 are integrally overlapped by a double winding machine (not shown).
FIG. 4B shows a state after the double winding is performed in this manner. As shown in FIG. 4B, a winding portion 18 is formed at a joint portion between the opening portion 11 x of the rectangular tube body 11 and the edge portion 12 x of the cover plate 12. The portion of the vertical reinforcing bead 111 in the tightening portion 18 is crushed and further flattened during the tightening. Therefore, both ends of the longitudinal reinforcing bead 111 are processed flat by the above-described processing of the flange 11a and the above-described winding tightening, and the portion between the ends flattened in this way, that is, the winding is tightened. The part other than the part keeps the original dent and functions as a longitudinal reinforcing bead 111 for reinforcement.

The edge part 12x of the cover plate 12 and the one opening part 11x of the rectangular cylinder 11 are wound by the double tightening method by the double tightening machine, and the shape shown in FIG. 4B is obtained.
This shape will be described in detail. As shown in FIG. 4C, the opening 11x of the rectangular cylinder 11 after double winding is an inclined part that is inclined obliquely from the inside of the square cylinder 11 to the outside. 11x1, a first linear portion 11x2 that is continuous with the inclined portion 11x1 and is linearly formed along the longitudinal direction (vertical direction) of the rectangular cylindrical body 11, and a linear cylindrical body 11 that is continuous with the first linear portion 11x2. A first bent portion 11x3 folded in a U-shape from the inside to the outside, and a second bent portion 11x3 that is continuous with the first bent portion 11x3 and is linearly formed along the longitudinal direction (vertical direction). A straight portion 11x4.

  On the other hand, as shown in FIG. 4D, the edge portion 12x of the lid plate 12 after double winding is bent from the center portion of the lid plate 12 toward the longitudinal direction (vertical direction) of the rectangular cylinder 11. A portion 12x4, a third straight portion 12x5 continuous with the second bent portion 12x4 and linearly formed in the longitudinal direction, and continuous with the third straight portion 12x5 and externally from the inside of the rectangular cylindrical body 11 A third bent portion 12x6 folded in a U-shape toward the direction, a fourth straight portion 12x7 connected to the third bent portion 12x6 and linearly formed along the longitudinal direction (vertical direction), A fourth bent portion 12x8 that communicates with the fourth linear portion 12x7 and that is folded back in the U-shape from the outside to the inside of the rectangular cylindrical body 11, and the fourth bent portion 12x8. Wherein the fifth straight portion 12x9 formed linearly along the longitudinal direction (vertical direction), and a too.

When the edge portion 12x of the cover plate 12 and the one opening portion 11x of the rectangular tube body 11 are overlapped with each other, the winding portion 18 shown in FIG. 4B is formed. The In general, double winding refers to a method in which the curled portion 12x3 of the cover plate 12 is wound around the flange 11a of the quadrangular cylinder 11, and is crimped and joined. Since the cover plate 12 and the rectangular cylinder 11 are doubled, it is called double winding.
And in this coiling | tightening part 18, one opening part 11x (end edge part) of the square cylinder 11 folded back so that it may become a U-shaped cross section, and the cover plate formed in the spiral shape by folding twice The 12 edge portions 12x are engaged with each other. As a result, in the tightening portion 18, as shown in FIG. A gap path including gaps 151, 152, 153, 154 is formed.

  This gap path will be described in more detail. As shown in FIG. 5, the gap 151a that directly communicates with the internal space of the rectangular cylinder 11 and has a curved shape, and the longitudinal direction of the square cylinder 11 that is continuous with the gap 151a. A linear gap 151 extending in the (vertical direction), a gap 154a continuous with the gap 151 and folded back in a U-shape from the inside of the rectangular cylinder 11 to the outside, and continued to the gap 154a. In addition, a linear gap 154 extending along the longitudinal direction, a gap 153a continuous with the gap 154 and folded back in a U shape from the outside toward the inside, and a gap 153a continuous with the gap 153a. A linear gap 153 extending in the direction, and continuous to the gap 153 and folded in a U-shape from the outside toward the inside. The gap 152a returning includes said longitudinal direction extends along a linear gap 152 to further direct communication with the outer space of the rectangular tube body 11 with connected to the gap 152a, the.

  When the pontoon 220 is damaged and the liquid storage product OL enters the floating chamber E, as shown in FIG. 6A, the floating body 10 receives an external pressure P1 from the surroundings by the liquid storage product OL filling the external space. Since the external pressure P1 is applied to the outer surface of the cover plate 12, the edge 12x of the cover plate 12 is pressed against the opening 11x of the rectangular cylinder 11, so that a part of the gap path (the contact portion 161 shown in the drawing) 162), line contact occurs along the shape of the opening 11x, and as a result, the gap path is blocked. By this blocking, it is possible to suppress as much as possible the liquid storage product OL that fills the periphery of the floating body 10 from entering the internal space of the floating body 10, and thus the buoyancy of the floating body 10 is maintained.

On the other hand, for example, when a fire occurs and the floating body 10 is heated from the surroundings, as shown in FIG. 6B, the air confined in the inside is also heated to increase the pressure (internal pressure P2). Due to the internal pressure P2, the edge 12x of the cover plate 12 tends to be slightly separated from the opening 11x of the rectangular cylindrical body 11, so that the gap path is blocked (locations 161 and 162 described above). A gap is formed. As a result, the substantially spiral gap path that communicates between the internal space and the external space of the floating body 10 is formed, and the pressure increase in the internal space can be reliably released (exhausted) to the external space. . Therefore, the floating body 10 can maintain its buoyancy without being damaged. Even if the size of the gap path is very small, air (gas) has a lower viscosity than the liquid storage product OL (liquid), and therefore can easily be ventilated.
As described above, when the edge portion 12x of the cover plate 12 approaches and separates from the opening portion 11x of the square cylindrical body 11, the gap path is opened or closed.

In the case of manufacturing a metal can as a general can container, a sealing material is put in portions corresponding to the inclined portion 12x1, the parallel portion 12x2, and the curled portion 12x3 of the lid plate 12, and then the lid The plate 12 and the rectangular tube body 11 are wound together, and the sealing material is filled in the four gaps 151 to 154 formed in the wound portion 18 to improve the sealing performance. The sealing material is used because the function as a container cannot be exhibited at all when the liquid stored in the metal can leaks, and there is no structure without the sealing material.
On the other hand, when manufacturing a metal can as the floating body 10 of the present embodiment, it is preferable to put a sealing material in the inclined portion 12x1, the parallel portion 12x2, and the curled portion 12x3 of the lid plate 12 on the contrary. Absent. This is because if the sealing material is sandwiched, the gaps 151 to 154 are filled with the sealing material after tightening. Normally, metal cans are used as containers, so a sealing material is essential. However, in the floating body 10 of the present embodiment, conversely, a gap is positively formed without using a sealing material. A configuration that cannot be conceived is adopted.

  In addition, each clearance gap dimension of the said four clearance gaps 151-154 can be adjusted with increase / decrease in the winding pressure by the said double winding machine. When the tightening pressure is increased, the tightening thickness dimension T (hereinafter simply referred to as T dimension) of the tightening portion 18 shown in FIG. 5 is decreased, and the clearance dimensions of the four clearances 151 to 154 are decreased. On the other hand, when the tightening pressure is reduced, the T dimension of the tightening portion 18 is increased, and the gap dimensions of the four gaps 151 to 154 are increased. The four gaps 151 to 154 in the winding fastening portion 18 serve as a gas (air) flow path between the internal space and the external space of the floating body 10 that forms a metal can. Therefore, by setting each gap dimension of these gaps 151 to 154 to an appropriate value, the floating roof type tank is maintained while minimizing the intrusion of the liquid storage product OL (liquid) as much as possible (while maintaining the buoyancy as much as possible). The deformation of expansion and contraction of the floating body 10 due to heating at the time of 100 fires and cooling after quenching can be suppressed as much as possible.

Hereinafter, the result of actually manufacturing the floating body 10 and performing the water immersion test and the heating / cooling test will be described.
Using a rectangular tube 11 having a pair of openings 11x with a plate thickness of 0.27 mm, and lid plates 12 and 13 with a plate thickness of 0.32 mm, it is made of a square metal having the following size. A floating body 10 (18 liter square can) was produced by double winding (the number of windings was 2). And the said T dimension in the winding fastening part 18 of this floating body 10 was changed, and the water immersion test and the heating-cooling test of the floating body 10 were done.
・ External dimensions of three sides of the floating body 10: 350.0 mm × 238.0 mm × 238.0 mm (the error of each side is within ± 1.0 mm)
-Mass of floating body 10: 1019g
-Capacity of the internal space of the floating body 10: 19.5L (liter)

Note that the intermediate position in the length direction along the approaching / separating direction of the tightening portion 18 (explained in FIG. 5, when the length of the tightening portion 18 is ML, the end portion of the tightening portion 18 is 1 / The average gap size (thickness) of the gaps 151, 152, 153, and 154 in the plane cross section at the 2 × ML position) is defined as follows. The thickness of the rectangular cylinder 11 is S _{1 in the} unit of mm, the plate thickness of the cover plates 12 and 13 is the unit of S _{2 in the} unit of mm, the thickness of the tightening portion 18 is T in the unit of mm, and the tightening When the number of turns of the portion 18 is R, the average gap dimension (thickness) G is defined by the following formula 1 in units of μm.
_{G = 1000 × {T-S} 1 × R-S 2 × (R + 1)} ÷ 2R ··· ( Equation 1)

First, the water immersion test of the floating body 10 will be described.
The thickness T of the winding part 18 was changed by 0.10 mm within a range of 1.70 mm to 2.70 mm. The floating body 10 was immersed in water and left for 48 hours. Then, the amount of water that entered the internal space of the floating body 10 after 48 hours was measured. As the amount of water immersion, the test was performed 5 times, and the average value was obtained. Table 1 shows the thickness T of the tightening portion 18, the average gap size G calculated from Equation 1 above, and the amount of water immersion.

  As shown in Table 1, in the floating body 10 having T = 1.70 mm (G = 50 μm) and T = 1.80 mm (G = 75 μm), the amount of water immersion was less than 30 ml. In the floating body 10 with T = 1.90 mm (G = 100 μm), T = 2.00 mm (G = 125 μm), T = 2.10 mm (G = 150 μm) and T = 2.20 mm (G = 175 μm) The amount was approximately 100 ml. In the floating body 10 with T = 2.30 mm (G = 200 μm), T = 2.40 (G = 225 μm), and T = 2.50 mm (G = 250 μm), the amount of water immersion was about 200 ml to about 300 ml. In the floating body 10 with T = 2.60 mm (G = 275 μm) and T = 2.70 mm (G = 300 μm), the amount of water immersion was 113 ml and 33 ml.

  Table 2 shows the relationship between the amount of water injected into the internal space of the floating body 10 and the submergence depth of the floating body 10, which was performed for confirmation. Here, the submergence depth of the floating body 10 represents the degree of sinking when the floating body 10 in which an arbitrary amount of water has been poured into the internal space is left in the water, and is the most of the three sides of the floating body 10 described above. The depth is expressed by how long a long side (350.0 mm) is submerged from the water surface. As shown in Table 2, the floating body 10 that has been poured (submerged) by about 500 ml has substantially the same submerged depth as compared with the floating body 10 that is not poured. That is, with a water injection amount (submerged amount) of about 500 ml, the floating body 10 can maintain sufficient buoyancy without affecting the buoyancy of the floating body 10.

  Therefore, it can be determined that all the floating bodies 10 shown in Table 1 in which the thickness T of the tightening portion 18 is 1.70 mm to 2.70 mm have sufficient buoyancy. In particular, the floating body 10 having a thickness T of the tightening portion 18 of 2.20 mm or less (an average gap dimension G of 175 μm or less) is preferable because the buoyancy can be maintained by minimizing water immersion.

Furthermore, the heating / cooling test of the floating body 10 was performed, and the following test results were obtained.
(1) Test 1
The floating body 10 having T = 1.7 mm (G = 50 μm) and T = 1.9 mm (G = 100 μm) was heated to 750 ° C. and held for 8 hours 30 minutes using an electric furnace. Thereafter, it was gradually cooled to 80 ° C. in a furnace over 16 hours. When the temperature reached 80 ° C., the floating body 10 was taken out of the electric furnace and rapidly cooled in the air. As a result, some contraction deformation occurred in the floating body 10. However, this contraction deformation is not contraction enough to reduce the buoyancy of the floating body 10.
(2) Test 2
The floating body 10 with T = 1.8 mm (G = 75 μm) was heated to 750 ° C. and held for 8 hours 30 minutes using an electric furnace. Thereafter, it was gradually cooled to 30 ° C. in a furnace over 40 hours. When it became 30 degreeC, the floating body 10 was taken out from the electric furnace. As a result, shrinkage deformation did not occur in the floating body 10.
(3) Test 3
The floating body 10 having T = 2.0 mm (G = 125 μm) was heated to 750 ° C. using an electric furnace. Immediately after reaching 750 ° C., the heater of the electric furnace was turned off and cooled to 300 ° C. in the furnace over 30 minutes. When the temperature reached 300 ° C., the floating body 10 was taken out of the electric furnace and rapidly cooled in the air. As a result, at the time of removal from the electric furnace (floating body temperature 300 ° C.), the floating body 10 did not undergo shrinkage deformation, but some shrinkage deformation occurred in the floating body 10 during rapid cooling in air. However, this contraction deformation is not contraction enough to reduce the buoyancy of the floating body 10.
(4) Test 4
The floating body 10 having T = 2.1 mm (G = 150 μm) and T = 2.2 (G = 175 μm) was heated to 750 ° C. using an electric furnace. Immediately after reaching 750 ° C., the heater of the electric furnace was turned off and cooled to 300 ° C. in the furnace over 30 minutes. When the temperature reached 300 ° C., the floating body 10 was taken out of the electric furnace and rapidly cooled in the air. As a result, shrinkage deformation did not occur in the floating body 10.
(5) Ring Fire Experiment of Actual Machine Size Pontoon 220 Fire test was conducted with the floating body 10 of T = 1.8 mm (G = 75 μm) housed in the actual machine size pontoon 220. The pontoon 220 was burned in a ring shape for 12 hours along the outer periphery. At this time, the maximum temperature reached by the floating body 10 inside the pontoon 220 was 750 ° C. After the pontoon 220 was spontaneously extinguished, the upper plate of the pontoon 220 was cooled with water, and the upper plate of the pontoon 220 was opened to rapidly cool the inside of the pontoon 220 in the air. As a result, it was rapidly cooled at 400 ° C. for about 9 minutes from when natural fire extinguishes (floating body temperature 700 ° C.) to when the upper plate of the pontoon 220 was opened (floating body temperature 300 ° C.). It was. However, some shrinkage deformation occurred in the floating body 10 while the upper plate of the pontoon 220 was opened and the inside of the pontoon 220 was rapidly cooled in the air. However, this contraction deformation is not contraction enough to reduce the buoyancy of the floating body 10.

From the above results, the following was found.
(1) T = 1.7 mm (G = 50 μm), T = 1.8 mm (G = 75 μm), T = 1.9 mm (G = 100 μm), T = 2.0 mm (G = 125 μm), T = 2 .1 mm (G = 150 μm) and T = 2.2. None of the floating bodies 10 of mm (G = 175 μm) are damaged by heating up to 750 ° C.
(2) If any of the floating bodies 10 are gradually cooled after the heating, the floating body 10 does not undergo shrinkage deformation (dents).
(3) The floating body 10 having T = 2.1 mm (G = 150 μm) and T = 2.2 mm (G = 175 μm) does not undergo shrinkage deformation (dent) even by rapid cooling after heating.
(4) T = 1.7 mm (G = 50 μm), T = 1.8 mm (G = 75 μm), T = 1.9 mm (G = 100 μm), and T = 2.0 mm (G = 125 μm) A certain floating body 10 is contracted and deformed by rapid cooling after heating, but is not contracted so as to reduce the buoyancy of the floating body 10.

  Generally, the larger the tightening thickness dimension T of the tightening portion 18, the larger the average gap dimension (thickness) G in the tightening portion 18, and the space between the internal space and the external space of the floating body 10. The distribution path of gas (air) becomes wider. Therefore, expansion and contraction deformation of the floating body 10 during heating and cooling are reduced. On the other hand, the smaller the T dimension, the smaller the average gap dimension (thickness) G, and the higher the airtightness of the floating body 10. Therefore, liquid intrusion from the external space of the floating body 10 is suppressed, and the buoyancy of the floating body 10 can be properly maintained for a long time.

  In other words, the performance required for the floating body 10 depends on whether emphasis is placed on buoyancy (sealing performance) or expansion / shrinkage deformation (air permeability) during heating and cooling. It is preferable to set the dimension and the average gap dimension G. All of the floating bodies 10 used in the above-described tests satisfy the performance related to the buoyancy (sealing property) and the expansion / contraction deformation (air permeability) required for the floating body 10. However, when the performance of either sealing performance or air permeability is regarded as important, the T dimension and the average gap dimension G of the floating body 10 may be appropriately set according to the request. As a result, deformation such as expansion and contraction due to temperature changes during a fire is reduced, and proper buoyancy can be maintained for a long period of time.

  According to the results of the above-described water immersion test and heating / cooling test, the floating body 10 (18 liter square can) used in the above test has a smaller amount of liquid ingress while ensuring a certain degree of gas (air) air permeability. Therefore, the T dimension is preferably 1.90 mm or more and 2.20 mm or less, that is, the average gap dimension G is 100 μm or more and 175 μm or less. In particular, in order to maintain the buoyancy of the floating body 10 appropriately by minimizing the expansion and contraction deformation of the floating body 10 and suppressing the liquid intrusion into the floating body 10 in the event of a fire of the floating roof tank 100, More preferably, the dimension is 2.1 mm or more and 2.2 mm or less, that is, the average gap dimension G is 150 μm or more and 175 μm or less.

  The preferable range of the T dimension is a value that varies depending on the thickness of the rectangular cylinder 11 and the cover plates 12 and 13 used for the floating body 10 and the number of windings. Since the range of the average gap dimension G is the average dimension (thickness) of the gap, it is a value that does not depend on the plate thickness, the number of windings, etc. of the floating body 10. Therefore, when using the floating body 10 having a plate thickness and the number of windings other than those used in the above test, the average gap dimension G of the floating body 10 is controlled to be within the above-described preferable range. That's fine.

In the above test, a metal can (18 liter square can) was used as the floating body 10, but the present invention is not limited to this, and a metal body having a fire resistance and a metal lid are wound together. Any structure may be used as long as the internal space is hollow.
Moreover, in the said test and the said embodiment, the winding with which the square cylinder 11 (metal cylinder) and the cover plates 12 and 13 (metal end plate) are double-tightening (the number of turns is 2). Although the body 10 is used, the number of windings of the floating body 10 is not limited to this, and the number of windings may be changed as necessary.

  Moreover, in the said test and said embodiment, both the two opening parts 11x of the square cylinder 11 are used as the cover plates 12 and 13 using the square cylinder 11 and the cover plates 12 and 13 which have a pair of opening part 11x. And the floating body 10 was formed. However, the floating body 10 is not limited to two places to be tightened, and it is sufficient that an opening is formed at least at one place and the space between the main body having the internal space and the lid body is tightened. In this case, since the overall length of the gap formed annularly along the opening 11x of the floating body 10 changes, the average gap dimension G may be controlled accordingly.

  The thickness of each of the rectangular cylinder 11 and the cover plates 12 and 13 is not limited to the plate thickness used in the above test (the tube thickness 0.27 mm and the lid plate thickness 0.32 mm), and as necessary. May be changed. However, it is preferable that each of the plate thickness of the rectangular cylinder 11 and the plate thicknesses of the cover plates 12 and 13 is 0.20 mm to 0.32 mm. When a material having a thickness within this range is used, it is possible to manufacture the floating body 10 by winding the rectangular tube body 11 and the cover plates 12 and 13 using an existing can manufacturing process manufacturing apparatus. . Therefore, the capital investment cost can be suppressed and the manufacturing cost can be reduced.

  Furthermore, in the said test and embodiment, although the square-shaped (cuboid shape) floating body 10 was used, the shape of the floating body 10 is not limited only to this. The shape of the floating body 10 may be a round shape (cylindrical shape such as a drum can) or other shapes. However, as described above, by forming the floating body 10 in a square shape, the plurality of floating bodies 10 can be accommodated in the floating chamber E of the pontoon 220 with less spatial loss. Therefore, it is preferable because a larger buoyancy of the pontoon 220 can be secured.

The floating body 10 of the present embodiment described above is summarized below.
(1) The floating body 10 of this embodiment is accommodated and used in the floating chamber E of the floating roof 200 of the floating roof type tank 100. And the opening part 11x is formed in two places, and the metal square cylinder 11 (main body) which has internal space, and the opening part 11x are covered, and the edge part 12x is wound around this opening part 11x. Attached metal lid plates 12 and 13 (lid body) are provided. And between the opening part 11x and the edge part 12x, between the external space of the square cylinder 11 (main body) and the said internal space, the square cylinder 11 (main body) and the cover plates 12 and 13 are communicated. The gap path (first gap) that allows the approaching / separating operation between the (cover bodies); and the gap path (when the lid plates 12 and 13 (cover body) are closest to the rectangular cylinder 11 (main body)) Contact portions 161 and 162 (first contact portions) that block the first gap) are provided.

(2) And the square cylinder 11 (main body) has comprised the cylinder which has a pair of opening part 11x. Further, lid plates 12 and 13 (lid bodies) are provided by the above-described tightening with respect to the respective openings 11x of the cylindrical body. Further, the gap path (the first path) between both the lid plate 12 and the one opening 11x to which the lid plate 12 is attached and between the lid plate 13 and the other opening 11x to which the lid plate 13 is attached. A clearance) and contact portions 161 and 162 (first contact portions) are provided.

(3) The floating body 10 of the present embodiment is a metal square can in which the cylindrical body 11 is square and the lid plates 12 and 13 (lid bodies) form a quadrangle.
(4) When the tightening portion 18 (the portion to be tightened) is viewed in the cross section of FIG. 5 including the approaching and separating direction, the opening 11x of the rectangular cylinder 11 (main body) and the cover plate 12, 13 (lid) 12x is engaged with the edge 12x.
(5) And each of the contact parts 161, 162 (first contact part) is formed in a ring shape along the opening part 11x, and the line contact part between the opening part 11x and the edge part 12x. It is.
(6) And the number of windings of the winding is 2. As described above, the number of windings may be further increased as necessary.

(7) Then, when the winding portion 18 (winded portion) between the opening portion 11x and the edge portion 12x is viewed in the cross section of FIG. 1 gap) connects the four gaps 151, 152, 153, 154 (linear gap portions) along the approaching / separating direction and the gaps 151, 152, 153, 154 (linear gap portions). There are three gaps 154a, 153a, and 152a (folding gap portions) that are folded back. Further, the gaps 151, 152, 153, and 154 (linear gap portions) are intermediate positions in the length direction of the gaps, and are positions of cross sections intersecting the approaching / separating direction. , The average gap dimension of these gaps 151, 152, 153, 154 (linear gap portions) is in the range of 100 μm or more and 175 μm or less.

(8) And the plate | board thickness of the square cylinder 11 (main body) exists in the range of 0.20 mm-0.32 mm. Furthermore, the plate | board thickness of the cover plates 12 and 13 (cover body) exists in the range of 0.20 mm-0.32 mm.

[Second Embodiment]
Then, the floating body 10 which concerns on 2nd Embodiment of this invention is demonstrated below. In the present embodiment, the structure of the rectangular cylinder 11 (main body) is particularly different from that of the first embodiment. Therefore, the differences will be mainly described, and the other structures are assumed to be the same as those of the first embodiment. A duplicate description is omitted.

  The rectangular cylinder 11 of the first embodiment has a structure in which a rectangular metal plate is bent and formed into a quadrangular rectangular shape, and then two opposite sides are overlapped and welded. As described above, in this embodiment, winding is used instead of welding. This will be described below with reference to FIGS. 7B and 7C.

  As shown in FIGS. 7B and 7C, the rectangular cylinder 11 has a cylindrical shape having a pair of the opening portions 11x by connecting the opposing two sides 19x and 19y of the rectangular metal plate 19 to each other. Yes. Then, this connection is a tightening, and the two sides 19x, 19y that communicate with each other between the inner space and the outer space of the rectangular cylindrical body 11 between the two sides 19x, 19y that are tightened are opposed to each other. A cylindrical gap 20 that allows an approaching / separating operation therebetween and cylindrical contact portions 211 and 212 that block the cylindrical gap 20 when the opposing two sides 19x and 19y are closest to each other are provided. Moreover, although it is preferable that the number of windings is 2 or more, this embodiment illustrates double winding. You may change the winding number of winding as needed.

In the floating body 10 of the present embodiment, in addition to the tightening between the opening 11x of the rectangular cylinder 11 and the edge 12x of the cover plates 12 and 13, a sealing material is similarly applied to the rectangular cylinder 11 itself. The winding structure which provided the clearance gap without interposing is employ | adopted. With such an additional structure, the air pressure in the internal space can be more reliably discharged by heating received in the event of a fire or the like.
That is, as shown in FIG. 7B, for example, when the pontoon 220 is damaged and the liquid storage product OL enters the floating chamber E, the floating body 10 applies an external pressure from the surroundings by the liquid storage product OL filling the external space. receive. Since the two sides 19x and 19y of the rectangular cylinder 11 are pressed by this external pressure, the rectangular cylinder 11 has a portion of the cylindrical gap 20 (the cylinder abutting portions 211 and 212 shown in the drawing). Line contact along the longitudinal direction occurs, and as a result, communication between the internal space and the external space of the rectangular tube 11 is blocked. By this blocking, it is possible to suppress as much as possible the liquid storage product OL that fills the periphery of the floating body 10 from entering the internal space of the floating body 10, and thus the buoyancy of the floating body 10 is maintained.
Moreover, as shown in FIG. 7C, for example, when a fire occurs and the floating body 10 is heated from the surroundings, the air confined in the internal space is also heated to increase the pressure. Due to this internal pressure, the two sides 19x and 19y of the rectangular cylinder 11 which are wound up tend to be slightly separated from each other, so that a gap is formed at the blocked location (the locations of the above-mentioned reference numerals 211 and 212). . As a result, the substantially spiral cylindrical gap 20 that communicates between the internal space and the external space of the floating body 10 is formed, and the pressure in the internal space is reliably released (exhausted) to the external space. Can do. Therefore, the floating body 10 can maintain its buoyancy without being damaged. Even if the separation distance is very small, air (gas) has a lower viscosity than the liquid storage product OL (liquid) and can be easily ventilated.

The floating body 10 of the present embodiment described above adopts the following configuration in addition to the configuration of the first embodiment.
(9) The rectangular cylinder 11 (main body) is formed by folding a rectangular metal plate 19 into a rectangular cylinder and joining two sides 19x and 19y facing each other. Furthermore, this joining is made by winding, and the space between the two sides 19x and 19y thus tightened is communicated between the internal space and the external space of the rectangular cylinder 11 (main body), and the two sides When the cylinder gap 20 (second gap) that allows an approaching and separating operation between 19x and 19y and the two sides 19x and 19y are closest to each other, the cylinder gap 20 (second gap) is blocked. Cylinder contact portions 211 and 212 (second contact portions) to be provided.
(10) The number of windings between the two sides 19x and 19y is two. As described above, the number of windings may be further increased as necessary.
(11) The cylindrical body contact portions 211 and 212 (second contact portions) are line contact portions between the two sides 19x and 19y.

  As a modification of the floating body 10 of the present embodiment described above, joining between each opening 11x of the rectangular cylinder 11 and each edge 12x of the cover plates 12 and 13 is made by welding, and The rectangular cylinder 11 may employ a configuration in which the joining between the opposing two sides 19x and 19y of the rectangular metal plate 19 is joined by winding. In this case, the cylinder gap 20 that allows the relative approaching and separating operation between the two opposite sides 19x and 19y and the cylinder that blocks the cylinder gap 20 when the two opposite sides 19x and 19y are closest to each other. The contact portions 211 and 212 satisfy the performance of the buoyancy of the floating body 10 (sealing property when immersed in the pontoon) and suppression of expansion / contraction deformation (air permeability when heated from the surroundings).

That is, in this modification, the following configuration can be adopted.
(12) The floating body 10 of the present modification is housed and used in the floating chamber E of the floating roof 200 of the floating roof type tank 100. Then, the rectangular metal plate 19 is folded into a quadrangular cylindrical shape, and the rectangular cylinder 11 (main body) in which two sides 19x and 19y facing each other are joined; and the opening 11x of the rectangular cylindrical body 11 (main body) is covered. A fixed lid plate 12, 13 (lid body); and the joining is performed by tightening, and the rectangular cylinder 11 (main body) is provided between the two sides 19x and 19y that are tightened. A cylindrical gap 20 (third gap) that allows communication between the internal space and the external space and allows the approach and separation between the two sides 19x and 19y; and the two sides 19x and 19y are mutually connected And cylinder contact portions 211 and 212 (third contact portions) that block the cylinder gap 20 (third gap) when they are closest to each other.
(13) The number of windings between the two sides 19x and 19y is 2 or more. As described above, the number of windings may be further increased as necessary.
(14) The cylindrical contact portions 211 and 212 (third contact portions) are line contact portions between the two sides 19x and 19y.

  According to the above aspect of the present invention, it is possible to provide a floating body that is excellent in fire resistance and can maintain an appropriate buoyancy even if there is a temperature change in the surrounding environment, and thus has high industrial applicability. .

10 Floating body (floating body, metal square can)
11 Square cylinder (main body, cylinder)
11a Flange 11x Opening 12, 13 Lid (lid)
12x Edge portion 12x1 Inclined portion 12x2 Parallel portion 12x3 Curl portion 151, 152, 153, 154 Clearance (linear gap portion, first gap)
152a, 153a, 154a Gap (folding gap part, first gap)
161, 162 Contact portion (first contact portion)
18 Tightening part 19 Metal plate 19x, 19y Opposing two sides 20 Cylindrical gap (second gap, third gap)
211, 212 Cylinder contact portion (second contact portion, third contact portion)
DESCRIPTION OF SYMBOLS 100 Floating roof type tank 200 Floating roof 210 Roof main body 220 Pontoon 221 Seal 223 Manhole E Floating chamber T Tightening thickness dimension

Claims (14)

A floating body accommodated in a floating chamber of a floating roof tank,
A metal body having an internal space in which an opening is formed in at least one place; and
Has an edge formed by spirally formed, covering the opening by the edge is engaged is seamed with respect to the opening, and external pressure or the receiving from the periphery of the floating body A metal lid attached so as to move toward and away from the main body by an internal pressure received from the inside of the floating body ;
Between the opening and the edge,
The external space of the main body and the internal space communicate with each other, and without allowing a sealing material to be interposed, the main body and the lid body are allowed to approach and separate , and the internal pressure causes the lid body to move from the main body. A first gap formed when spaced apart ;
A first abutting portion that blocks the first gap when the lid is closest to the main body by the external pressure ;
The floating body characterized by being provided. The main body forms a cylinder having a pair of the openings;
The lid body is provided by tightening with respect to each of the openings of the cylindrical body;
One of the lids and one of the openings to which the one lid is attached, and between the other of the lids and the other of the openings, the first gap and the first 1 abutment is provided;
The floating body according to claim 1.   The floating body according to claim 1, wherein the floating body is a metal square can.   The said opening part of the said main body and the said edge part of the said cover body are latching, when the said fastening part is seen in the cross section containing the said approaching / separating direction, The said edge part of the said cover body has latched. The floating body as described in any one of 3.   The said 1st contact part is a line contact part between the said opening part and the said edge part formed cyclically | annularly along the said opening part, The any one of Claims 1-4 characterized by the above-mentioned. The floating body as described in.   The floating body according to any one of claims 1 to 5, wherein the number of windings of the tightening is 2 or more. When the wound portion between the opening and the edge portion is viewed in a cross section along the approaching / separating direction, the first gap is a plurality of linear gap portions along the approaching / separating direction. And a folded back gap portion that folds the straight gap portions together to fold back;
When each of the linear gap portions is viewed at a cross-section intersecting the approaching / separating direction at an intermediate position in the length direction, an average gap size of these linear gap portions is in a range of 100 μm or more and 175 μm or less. Is within;
The floating body according to claim 6. The thickness of the main body is in the range of 0.20 mm to 0.32 mm;
The lid has a thickness of 0.20 mm to 0.32 mm;
The floating body as described in any one of Claims 1-7 characterized by the above-mentioned. The main body is formed by folding a rectangular metal plate into a cylindrical shape and joining two opposite sides;
The joint is wound and the opposing two sides are engaged, and the two sides are tightened so as to relatively move toward and away from each other by the external pressure or the internal pressure . Between the two sides, the internal space and the external space of the main body are communicated with each other, and an approaching / separating operation between the two sides is allowed, and the two sides are relatively separated by the internal pressure. A second gap sometimes formed ;
A second contact portion that blocks the second gap when the two sides are closest to each other by the external pressure ;
The floating body according to claim 1, wherein the floating body is provided.   The floating body according to claim 9, wherein the number of windings between the two sides is two or more.   The floating body according to claim 9 or 10, wherein the second contact portion is a line contact portion between the two sides. A floating body accommodated in a floating chamber of a floating roof tank,
A main body obtained by folding a rectangular metal plate into a cylindrical shape and joining two sides facing each other;
A lid secured over the opening of the body;
With
The joining is wound and the two opposing sides are engaged, and the two sides are relatively moved by the external pressure received from the periphery of the floating body or the internal pressure received from the inside of the floating body. Between the two sides wound so as to move toward and away from each other ,
When the internal space and the external space of the main body are communicated to allow the approaching and separating operation between the two sides without interposing a sealing material, and the two sides are relatively separated by the internal pressure. A third gap formed in ;
A third contact portion that blocks the third gap when the two sides are closest to each other by the external pressure ;
The floating body characterized by being provided.   The floating body according to claim 12, wherein the number of windings between the two sides is two or more.   The floating body according to claim 12 or 13, wherein the third contact portion is a line contact portion between the two sides.

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