JP4990816B2 - Exterior body for water storage tank - Google Patents

Description

  The present invention relates to a water tank exterior body that houses a water tank installed outdoors.

  In recent years, a natural refrigerant heat pump type electric water heater has been proposed in which heat in the atmosphere is taken in through a heat exchanger in a heat pump unit, and the taken-in heat is transferred to a water storage tank to make water hot. Water storage tanks in natural refrigerant heat pump type electric water heaters are usually installed outdoors, but in order to protect the control devices mounted on them from external forces such as rainwater and wind, such water storage tanks are housed in a water tank exterior body. There are many cases (see, for example, Patent Document 1).

  FIG. 8 shows an example of a conventional water tank exterior body 7. The water storage tank exterior body 7 has a rectangular cross section, and is provided with four circumferential walls 71 having a thickness of 1 mm or less. By the way, when attention is paid to one peripheral wall surface 71, it is assumed that it consists of a size of height H and width L.

For example, as shown in FIG. 9 (a), when the point load P acts on the inside of such a peripheral wall 71, it is bent inward over the deflection δ1 as shown by the dotted line in the figure. . Further, when a positive wind pressure of W (Pa = N / m ² ) acts on such a peripheral wall surface, the peripheral wall surface 71 having a width L is, for example, as shown by a dotted line in the drawing of FIG. 9B. In other words, bending deformation occurs inwardly over the deflection δ2. On the other hand, when a negative wind pressure is applied, it is bent and deformed over the outer deflection δ3 as indicated by the dotted line in FIG. 9C.

  In particular, since the water tank exterior body 7 is often transported by an operator's hand, a point load is often applied to the peripheral wall surface 71 as shown in FIG. As described above, since it is of the nature of being installed outdoors, as shown in FIGS. 9B and 9C, positive and negative wind pressures often act. At this time, the bending deformation as described above occurs, and the deflections δ1, δ2 or δ3 act in each case, and this deflection δ1, δ2 or δ3 is maximum at the central portion of the peripheral wall surface 71 in particular. It becomes. If the peripheral wall surface 71 is greatly bent, the water tank exterior body 7 cannot be transported in a stable state. Moreover, even if this is placed outdoors, the peripheral wall surface 71 is greatly deformed every time it receives positive or negative wind pressure, and the exterior body becomes unstable.

Further, in order to improve the out-of-plane bending rigidity in order to counter such wind pressure and point load by a human hand, a method of increasing the thickness of the peripheral wall surface 71 can be considered. However, increasing the thickness of the peripheral wall 71 increases the overall weight of the water tank exterior body 7, which causes problems in transporting it, and further increases the material cost. There was also a problem.
JP 2007-225198 A

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to improve the out-of-plane bending rigidity without increasing the thickness of the peripheral wall surface. The object of the present invention is to provide a water tank exterior body that is lighter than conventional ones.

In order to solve the above-described problems, a water tank exterior body to which the present invention is applied is a water tank exterior body that accommodates a water tank installed outdoors. Four peripheral wall surfaces having an angle of 90 ° between the mating surfaces, and an inclined surface interposed between the end portions of the adjacent peripheral wall surfaces and arranged to be inclined with respect to the peripheral wall surfaces, The inclined surface is provided in at least one or more of a total of four corners formed between the adjacent peripheral wall surfaces, and the adjacent circumference is provided in a corner where the inclined surface is not provided. The wall surfaces are extended and connected to each other. Further, when the smaller value of the distances between the opposed peripheral wall surfaces is Ls, and the width Dw / √2 of the inclined surface is D, D = α ₁ × Ls ........ (1), wherein alpha ₁ ≦ 0. Exterior body for water storage tank, which is a 93.

In order to solve the above-described problems, a water tank exterior body to which the present invention is applied is a water tank exterior body that accommodates a water tank installed outdoors. Four peripheral wall surfaces having an angle of 90 ° between the mating surfaces, and an inclined surface interposed between the end portions of the adjacent peripheral wall surfaces and arranged to be inclined with respect to the peripheral wall surfaces, The inclined surface is provided in at least 2 to 4 out of a total of 4 corners formed between the adjacent peripheral wall surfaces, and when the inclined surface is provided in 2 locations, one inclined surface is provided. This is provided at both ends of the wall, and the adjacent peripheral wall is extended and connected to each other at the corner where the inclined surface is not provided. Ls, and the width Dw / √ of the inclined surface The when the _{D, D = α 2 × Ls} ········ (2), _{where, 0.05 ≦ α 2 ≦ 1/} 2 - {(6M / σ cr) 1.5} / (24K) and α ₂ ≦ 0.293, A water tank outer packaging body.

In order to solve the above-described problems, a water tank exterior body to which the present invention is applied is a water tank exterior body that accommodates a water tank installed outdoors. Four peripheral wall surfaces having an angle of 90 ° between the mating surfaces, and an inclined surface interposed between the end portions of the adjacent peripheral wall surfaces and arranged to be inclined with respect to the peripheral wall surfaces, The inclined surface is provided at one of a total of four corners formed between the adjacent peripheral wall surfaces, or at two locations so as to be diagonal to each other, and the inclined surface is provided. The adjacent peripheral wall surfaces are extended and connected to each other at the corners not formed, and the smaller value of the interval between the opposing peripheral wall surfaces is Ls, and the width Dw / √2 of the inclined surface is when the _{D, D = α 3 × Ls} ····· ... (2), where, 0.05 ≦ α ₃ ≦ 1 - water, characterized in that a ^{_{{(6M / σ cr) 1.5}} } / (12K), and a alpha ₂ ≦ 0.293 Tank exterior.

Here, M = (w × Ls ² ) / 8, K = (5 × w × Ls ⁴ ) / (384 × E × δ)
σ _cr : Fatigue limit strength (N / mm ² ) of the material constituting the peripheral wall surface
w: Uniformly distributed load (N / mm) acting on the width of 1 mm at the center in the height direction of the peripheral wall surface
Ls: The smaller value (mm) of the distance between the opposing peripheral wall surfaces
E: Young's modulus of the peripheral wall surface (N / mm ² )
δ: Out-of-plane deformation (mm) allowed at the center in the height direction of the peripheral wall

  In the present invention having the above-described configuration, even when a point load is applied to the peripheral wall surface through the operator's hand, the peripheral wall surface is not greatly bent. For this reason, the exterior body for water storage tanks to which the present invention is applied can be realized as a configuration excellent in transportability.

  In addition, the outer casing for a water storage tank to which the present invention is applied can form a more stable outer casing because the peripheral wall surface is not greatly deformed even when wind pressure is applied. In addition, the exterior body for a water storage tank to which the present invention is applied can improve the out-of-plane bending rigidity without increasing the thickness of the peripheral wall surface. For this reason, it can be set as a suitable structure in aiming at weight reduction, but it becomes possible to improve an assembly workability | operativity and to set it as the structure excellent also in economical efficiency.

  Hereinafter, as a best mode for carrying out the present invention, a water tank exterior body that houses a water tank installed outdoors will be described in detail with reference to the drawings.

  FIG. 1 is an exploded perspective view of a water tank exterior body 1 to which the present invention is applied, and FIG. 2 is a horizontal sectional view of the water tank exterior body 1 to which the present invention is applied.

  This water tank exterior body 1 has a substantially octagonal cross section, and has four peripheral wall surfaces 11a to 11d whose opposing surfaces are substantially parallel to each other and whose angle between adjacent surfaces is approximately 90 °. And inclined surfaces 12 a to 12 d interposed between the end portions of the peripheral wall surfaces 11 a to 11 d, a bottom portion 13, and a lid 14. The bottom 13 and the lid 14 may be omitted from the configuration of the water tank exterior body 1.

  The peripheral wall surface 11 is made of a steel plate, has a height of H, and a width of l. The peripheral wall surface 11a is a surface facing the peripheral wall surface 11c, and these are substantially parallel to each other. The peripheral wall surface 11b is a surface facing the peripheral wall surface 11d, and these are substantially parallel to each other. Note that the interval between the opposed peripheral wall surfaces is Ls.

  The inclined surface 12 is made of a steel plate, has a height of H, and a width of Dw.

  The inclined surface 12a is interposed between the adjacent peripheral wall surface 11d and the end of the peripheral wall surface 11a, and is inclined at an angle of approximately 45 ° with respect to the adjacent peripheral wall surface 11d and the peripheral wall surface 11a. The inclined surface 12b is interposed between the end portions of the adjacent peripheral wall surface 11a and the peripheral wall surface 11b, and is inclined at approximately 45 ° with respect to the adjacent peripheral wall surface 11a and the peripheral wall surface 11b. The inclined surface 12c is interposed between the adjacent peripheral wall surface 11b and the end part of the peripheral wall surface 11c, and is inclined at approximately 45 ° with respect to the adjacent peripheral wall surface 11b and the peripheral wall surface 11c. The inclined surface 12d is interposed between the adjacent peripheral wall surface 11c and the end of the peripheral wall surface 11d, and is inclined at an angle of approximately 45 ° with respect to the adjacent peripheral wall surface 11c and the peripheral wall surface 11d. Moreover, when the projection length on the same plane as the peripheral wall surface 11 in these inclined surfaces 12 is set to D, since the inclined surface 12 is inclined substantially 45 degrees with respect to the peripheral wall surface 11, this D is It is expressed by Dw / √2. As shown in FIG. 2, the interval Ls between the peripheral wall surfaces is expressed by Ls = 2 × D + 1.

  In order to more efficiently realize the weight reduction of the water tank exterior body as the object of the present invention from the viewpoint of shortening the sectional development length of the peripheral wall surface, Most preferably, the angle formed by the surface is approximately 45 °. The reason will be described with reference to FIGS. 3A and 3B by taking the peripheral wall surfaces 11a and 11b and the inclined surface 12b narrowed by these as an example.

  In FIG. 3A, D1 is the projection length from one inclined surface 12b to one peripheral wall surface 11a, and D2 is the projection length from the inclined surface 12b to the other peripheral wall surface 11b. In FIG. 3B, the ratio of the width Dw of the inclined surface to the total value (D1 + D2) of these projection lengths (corresponding to the reduction rate of the cross-sectional development length at the corner of 1) is taken as the vertical axis, and the peripheral wall surface 11a , 11b and the inclined surface 12b, the relationship between the two is shown with the angle θ as the horizontal axis.

  From the tendency of FIG. 3 (b), it can be seen that as the value of Dw / (D1 + D2) is set smaller, the cross-sectional developed length of the water tank exterior body 1 can be more effectively reduced. For this reason, it can be said that the angle θ between the peripheral wall surface and the inclined surface is 45 °, which is most efficient. If the angle θ is 28 ° or more and 62 ° or less, the reduction effect is almost the same as the reduction effect in the case of 45 ° (the reduction rate reaches 95% or more of the reduction rate at 45 °). Further, if the angle θ is 35 ° or more and 55 ° or less, the reduction effect is almost the same value as in the case of 45 °. It can be seen from the tendency of the curve shown in FIG. 3B that the reduction rate at 45 ° reaches 98.5% or more by setting the angle θ to 35 ° or more and 55 ° or less.

  Further, as shown in FIG. 2, the water tank exterior body 1 is assumed to have a volume and shape that can accommodate a water tank 2 having a circular cross section represented by a dotted line. The water storage tank 2 is assumed to be, for example, a natural refrigerant heat pump type electric water heater that takes in heat from the atmosphere via a heat exchanger in the heat pump unit and transfers the taken heat to the tank to make water hot water. However, it is intended to include a water storage tank of any use that can be placed outdoors. The water storage tank 2 may be covered with a heat insulating material such as polystyrene foam on the outer periphery of the cylindrical tank.

Here, D may be based on the following equation (1).
D = α ₁ × Ls (1),
Here, α ₁ ≦ {1-tan (π / 8)} / 2 = 0.293
When this equation (1) is transformed, Dw is expressed by the following (1) ′.
Dw = √2 × α ₁ × Ls (1) ′

  As shown in FIGS. 7 (a) and 7 (b), the formula (1) ′ is provided at two to three of the four corners formed between the adjacent peripheral wall surfaces 11, When the inclined surfaces are provided at two places, as shown in FIG. 7 (b), the case where the inclined surfaces are provided at both ends of one peripheral wall surface 11 can be similarly expressed.

Further, this D may be based on the following equation (2).
D = α ₂ × Ls (2)
However, 0.05 ≦ α ₂ ≦ 1/2 − {(6M / σ _cr ) ^1.5 } / (24K) and α ₂ ≦ 0.293.

Furthermore, this D is especially when there is one inclined surface 12 as shown in FIG. 7 (c), and there are two inclined surfaces 12 as shown in FIG. 7 (d), and the two inclined surfaces. In the case where 12 are arranged diagonally so as to face each other, the following formula may be used.
D = α ₃ × Ls (2-1)

However, 0.05 ≦ α ₂ ≦ 1-{(6M / σ _cr ) ^1.5 } / (12K) and α ₂ ≦ 0.293.
Here, M = (w × Ls ² ) / 8, K = (5 × w × Ls ⁴ ) / (384 × E × δ)
σ _cr : Fatigue limit strength (N / mm ² ) of the material constituting the peripheral wall surface
w: Uniformly distributed load (N / mm) acting on the width of 1 mm at the center in the height direction of the peripheral wall surface
Ls: The smaller value (mm) of the distance between the opposing peripheral wall surfaces
E: Young's modulus of the peripheral wall surface (N / mm ² )
δ: Out-of-plane deformation (mm) allowed at the center in the height direction of the peripheral wall

  4 (a) shows δ as an out-of-plane deformation amount (mm) allowed in the central portion in the height direction of the peripheral wall surface, and FIG. 4 (b) shows a case where a point load P is applied. FIG. 4 (c) shows an example in which an evenly distributed load (N / mm) w acting on a width of 1 mm in the central portion in the height direction of the peripheral wall surface is applied. Hereinafter, a case where an evenly distributed load (N / mm) w is applied will be described as an example. However, when a point load P is applied, the same effect can be obtained by the same mechanism.

  First, when Expression (2) is transformed, Dw is expressed by the following (2) '.

Dw = √2 × α ₁ × Ls (2) ′

  Hereinafter, the reason for the numerical limitation in the exterior body 1 for a water storage tank to which the present invention is applied will be described in detail.

First as the top concept, geometrically, D is not able to greater than alpha _1. This is as defined in the above formula (1).

  Next, the minimum value of D for which the effect of the present invention can be found and the maximum value of D determined by the fatigue strength will be described.

Regarding the setting of the minimum value of D, α ₂ in the formula (2) needs to be 0.05 or more in order to enjoy a sufficient weight reduction effect. If α ₂ = 0.05, the plate thickness is independent of the Ls dimension and plate thickness, as compared to the conventional water tank exterior body 7 having a rectangular cross section as shown in FIG. Even when the thickness is reduced to 0.87 times, the deformation amount can be maintained substantially the same when the same load is applied. Specifically, by setting α ₂ = 0.05, when the thickness of the conventional water tank exterior body 7 is 1.0 mm, in the water tank exterior body 1 to which the present invention is applied, By setting the thickness to 0.9 mm, it is possible to suppress with almost the same deformation amount. In addition, by setting α ₂ = 0.05, when the plate thickness of the conventional water tank exterior body 7 is 0.9 mm, the water tank exterior body 1 to which the present invention is applied has a thickness of 0. By setting the thickness to 8 mm, it is possible to suppress the deformation with substantially the same amount of deformation. As described above, the water tank exterior body 1 to which the present invention is applied is compared with the conventional water tank exterior body 7, even if the thickness of the steel material is reduced by one size (approximately 0.1 mm), The amount of deformation when the same load is applied can be suppressed to approximately the same level.

Regarding the setting of the maximum value of D, as D is increased to α ₁ and α ₂ , the thickness of the peripheral wall surface 11 and the inclined surface 12 can be reduced to reduce the weight. However, when D is increased and the thickness of the peripheral wall surface 11 and the inclined surface 12 is reduced, the bending stress applied to the peripheral wall surface 11 and the inclined surface 12 increases. In particular, when a wind pressure is applied to the peripheral wall surface 11 and the inclined surface 12, a repeated load is applied, so that it is necessary to consider the problem of fatigue. Here, the value of D when the fatigue limit strength is σ _cr (N / mm ² ) is set to the maximum value. The reason is that when the value of D exceeds the fatigue limit strength, the peripheral wall surface 11 and the inclined surface 12 may be subject to fatigue failure. The fatigue limit strength σ _cr is based on the document “Fatigue Design Guidelines for Steel Structures / Comments / Edited by the Japan Steel Structure Association”, and σ _cr = 190 N / mm ² as a sufficiently safe value. This value is an engineered value on the assumption that even when the number of repetitions reaches 2 × 10 ⁶ times or more, it does not break due to fatigue, and it is considered that using this value is sufficiently safe.

With regard to the main load conditions and deformation, attention is paid to negative bending due to wind, that is, outward deflection. Here, the theoretical formula (approximation formula) of deformation is shown in formula (3).
δ = (5w × l ⁴ ) / (384 × E × I) (3)

  Here, l is a span serving as a reference for bending deformation. Since the wind load acts evenly or arbitrarily distributed on any surface of the exterior material, the exact calculation of δ needs to be based on the “theoretical formula for out-of-plane bending of the plate”. However, the deformation amount δ of the central portion of the peripheral wall surface 11 in the water tank exterior body 1 to which the present invention is applied approximates the “beam” in the central portion in the height direction as shown in the figure, so that the value thereof can be almost accurately Can be requested.

  Thereafter, the calculation proceeds based on the “beam model” set to a width of 1 mm.

When the formula (3) is arranged with respect to I under the condition of l = Ls (1-2α ₂ ) as the required stiffness and the required plate thickness, the following formula giving the required stiffness of the beam model is obtained.

Here, the required rigidity is the cross-sectional secondary moment I (mm ⁴ ) necessary for suppressing deformation at the center of the beam to be δ or less when the equally distributed load w acts on the beam model.
I = K (1-2α ₂ ) ⁴ (4)
Here, K = (5w × L ⁴ ) / (384 × E × δ), and α ₂ is the ratio of D to Ls (α ₂ = D / Ls).

On the other hand, when the thickness of the peripheral wall surface 11 is t, the retained rigidity of the beam model (the bending rigidity per unit width possessed by the beam model) is given by the following equation (5).
^{I = t 3/12 ········· (} 5)

From the formulas (4) and (5), the required plate thickness (the plate thickness t of the peripheral wall surface 11 required to exhibit the required rigidity shown in the formula (4)) is given by the following formula (6).
t = {12K (1-2α ₂ ) ⁴ } ^1/3 (6)

  Next, calculation of bending stress acting on the beam model will be described.

The acting force σa on the beam model is given by the following equation. Here, the “acting force” indicates a bending stress acting on the beam when it is deformed to the limit point of the required rigidity shown in the equation (4).
σa = M (1-2α ₂ ) ² × (6 / t ² ) (7)
Here M = w × ^L 2/8

By substituting equation (6) into equation (7), the following equation (8) is obtained.
^{σa = 6M (12K) -2/3 ×} (1-2α 2) -2/3 ········· (8)

Next, comparison with fatigue limit strength will be described. In the equation (6), σa is equal to the maximum bending stress generated when an evenly distributed load of w acts on the beam model. In order to take into account breakage of the plate due to fatigue, σa in the equation (8) must be smaller than the fatigue limit strength σ _cr . That is, it is necessary to satisfy the following formula (9).
^{6M (12K) -2/3 × (1-2α} 2) -2/3 ≦ σ cr ········· (9)

This is arranged for α ₂ to obtain the following equation.
α ₂ ≦ 1/2 − {(6M / σ _cr ) ^1.5 } / (24K) (10)
The basis of the maximum value of α ₂ is given by equation (10).

In particular, when there is one inclined surface as shown in FIG. 7 (c), there are two inclined surfaces as shown in FIG. 7 (d), and the two inclined surfaces are arranged to face each other. In this case, since the relationship between l and Ls described above is l = Ls (1-α ₃ ), equation expansion is omitted, but in equation (10), coefficients are rewritten as in the following equation: .
α ₂ ≦ 1-{(6M / σ _cr ) ^1.5 } / (12K) (10) ′
(10) The 'expression, the basis of the maximum value of the alpha _3.

  The water tank exterior body 1 to which the present invention having the above-described configuration is applied has a large deflection of the peripheral wall surface 11 even when a point load is applied to the peripheral wall surface 11 through a worker's hand. Disappears. For this reason, the exterior body 1 for a water storage tank to which the present invention is applied can be realized as a configuration excellent in transportability.

  In addition, the water tank exterior body 1 to which the present invention is applied can form a more stable exterior body because the peripheral wall surface 11 is not greatly deformed even when wind pressure is applied. Moreover, the water tank exterior body 1 to which the present invention is applied can improve the out-of-plane bending rigidity without increasing the thickness of the peripheral wall surface 11. For this reason, it can be set as a suitable structure in aiming at weight reduction, but it becomes possible to improve an assembly workability | operativity and to set it as the structure excellent also in economical efficiency.

  FIG. 5 shows an example in which D is increased to the maximum. In the form shown in FIG. 4 as well, the expected effect described above is obtained.

  Next, another embodiment of the water tank exterior body 1 to which the present invention is applied will be described. As shown in FIG. 6, it is considered that a total of four corners 15 are virtually formed between the four peripheral wall surfaces 11. Specifically, among the four peripheral wall surfaces 11a to 11d, between the peripheral wall surface 11a and the peripheral wall surface 11b, between the peripheral wall surface 11b and the peripheral wall surface 11c, between the peripheral wall surface 11c and the peripheral wall surface 11d, The corners 15 are virtually formed between the wall surface 11d and the peripheral wall surface 11a.

  An inclined surface 12 is provided in the virtually formed corner 15. In the form of FIG. 2 mentioned above, the example which provided the inclined surface 12 in all four places among the corner parts 15 of a total of four places is shown. However, this inclined surface 12 should just be provided in at least 1 place among the corner parts 15 of a total of 4 places.

  FIG. 7A shows an example in which the inclined surfaces 12 are provided at three places out of a total of four corners 15. FIGS. 7B and 7D show an example in which the inclined surfaces 12 are provided at two places out of the four corners 15 in total. FIG. 7C shows an example in which the inclined surface 12 is provided at one of the four corners 15 in total.

  In addition, it is set as the structure where the adjacent surrounding wall surface 12 was extended and connected mutually in the corner part 15 in which the inclined surface 12 is not provided.

  Thus, it is not necessary that the inclined surfaces 15 are provided in all the corners 15, and it is a matter of course that the above-described advantageous effects of the present invention can be obtained if the inclined surfaces 15 are provided in at least one place. is there.

  Of course, the rectangle drawn by extending the peripheral wall surfaces 11a to 11d may be a square or a rectangle.

The basic external dimensions of the water supply tank are 700 × 750 mm, that is, Ls = 700 (mm), the load due to wind pressure is W = 1500 (Pa), and converted to a beam model, w = 0.015 (N / mm ), The allowable deformation amount is δ = 30 (mm), the Young's modulus of the peripheral wall surface 11 made of steel is E = 205000 (MPa), and the circumference made of steel is Consider the case where the fatigue limit strength of the wall surface 11 is σ _cr = 190 (MPa).

In this case, the minimum value of D: 0.05 × 700 = 35 (mm)
Maximum value of D: One of the following values is smaller.
Calculation based on equation (10): 0.23 × 700 = 161 (mm)
Calculation based on equation (1): 0.293 × 700 = 205.1 (mm)
In this case, it is preferable to set D in the range of 35 mm to 161 mm.

The basic external dimensions of the water supply tank are 730 × 630 mm, that is, Ls = 630 (mm), the load by wind pressure is W = 1000 (Pa), and converted to a beam model, w = 0.015 (N / mm ), The allowable deformation amount is δ = 15 (mm), the Young's modulus of the peripheral wall surface 11 made of steel is E = 205000 (MPa), and the circumference made of steel is Consider the case where the fatigue limit strength of the wall surface 11 is σ _cr = 190 (MPa).

In this case, the minimum value of D: 0.05 × 630 = 31.5 (mm)
Maximum value of D: One of the following values is smaller.
Calculation based on equation (10): 0.378 × 630 = 238.1 (mm)
Calculation based on equation (1): 0.293 × 630 = 184.6 (mm)
In this case, it is preferable to set D in the range of 31.5 mm to 184.6 mm.

It is a disassembled perspective view of the exterior body for water storage tanks to which the present invention is applied. It is a horizontal sectional view of the exterior body for water storage tanks to which the present invention is applied. It is a figure for demonstrating the reason why it is most desirable to comprise the angle which a surrounding wall surface and an inclined surface make at about 45 degrees. It is a figure shown about the span used as the reference | standard of bending deformation. It is a figure which shows the example at the time of extending D to the maximum in the exterior body for water tanks to which this invention is applied. It is a figure for demonstrating other embodiment in the exterior body for water storage tanks to which this invention is applied. It is a figure which shows the example which provided the inclined surface in 1-3 places among the corner parts of a total of 4 places. It is a perspective view of the conventional exterior body for water storage tanks. It is a figure for demonstrating the behavior when a load is loaded with respect to the exterior body for water storage tanks in the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior body for water storage tank 2 Water storage tank 11 Circumferential wall surface 12 Inclined surface 13 Bottom portion 14 Lid 15 Corner portion

Claims (3)

In a water tank exterior body that houses a water tank installed outdoors,
Four peripheral wall surfaces whose opposing surfaces are substantially parallel to each other and whose angle between adjacent surfaces is approximately 90 °;
An inclined surface interposed between the end portions of the adjacent peripheral wall surfaces, and inclined with respect to the peripheral wall surface,
The inclined surface is provided at 1 to 4 locations out of a total of 4 corners formed between adjacent peripheral wall surfaces,
In the corner where the inclined surface is not provided, the adjacent peripheral wall surfaces are extended and connected to each other,
Further, when the smaller value of the distance between the opposing peripheral wall surfaces is Ls and the width of the inclined surface is Dw, Dw = √2 × α ₁ × Ls (1), where α ₁ ≦ 0.293
An exterior body for a water storage tank. In a water tank exterior body that houses a water tank installed outdoors,
Four peripheral wall surfaces whose opposing surfaces are substantially parallel to each other and whose angle between adjacent surfaces is approximately 90 °;
An inclined surface interposed between the end portions of the adjacent peripheral wall surfaces, and inclined with respect to the peripheral wall surface,
The inclined surface is provided in at least 2 to 4 out of a total of 4 corners formed between the adjacent peripheral wall surfaces, and when the inclined surface is provided in 2 locations, one inclined surface is provided. This is provided at both ends of the wall,
In the corner where the inclined surface is not provided, the adjacent peripheral wall surfaces are extended and connected to each other,
The width Dw of the inclined surface is expressed by the following equation (2): Dw = √2 × α ₂ × Ls (2)
However, 0.05 ≦ α ₂ ≦ 1/2 − {(6M / σ _cr ) ^1.5 } / (24K), and α ₂ ≦ 0.293, characterized in that α ₂ ≦ 0.293 .
Here, M = (w × Ls ² ) / 8, K = (5 × w × Ls ⁴ ) / (384 × E × δ)
σ _cr : Fatigue limit strength (N / mm ² ) of the material constituting the peripheral wall surface
w: Uniformly distributed load (N / mm) acting on the width of 1 mm at the center in the height direction of the peripheral wall surface
Ls: The smaller value (mm) of the distance between the opposing peripheral wall surfaces
E: Young's modulus of the peripheral wall surface (N / mm ² )
δ: Out-of-plane deformation (mm) allowed at the center in the height direction of the peripheral wall In a water tank exterior body that houses a water tank installed outdoors,
Four peripheral wall surfaces whose opposing surfaces are substantially parallel to each other and whose angle between adjacent surfaces is approximately 90 °;
An inclined surface interposed between the end portions of the adjacent peripheral wall surfaces, and inclined with respect to the peripheral wall surface,
The inclined surface is provided at at least one of the four corners formed between the adjacent peripheral wall surfaces, or at two locations so as to be diagonal to each other,
In the corner where the inclined surface is not provided, the adjacent peripheral wall surfaces are extended and connected to each other,
The width Dw of the inclined surface is expressed by the following equation: Dw = √2 × α ₃ × Ls ()
However, 0.05 ≦ α ₃ ≦ 1-{(6M / σ _cr ) ^1.5 } / (12K) and α ₃ ≦ 0.293, wherein the water tank exterior body is characterized in that:
Here, M = (w × Ls ² ) / 8, K = (5 × w × Ls ⁴ ) / (384 × E × δ)
σ _cr : Fatigue limit strength (N / mm ² ) of the material constituting the peripheral wall surface
w: Uniformly distributed load (N / mm) acting on the width of 1 mm at the center in the height direction of the peripheral wall surface
Ls: The smaller value (mm) of the distance between the opposing peripheral wall surfaces
E: Young's modulus of the peripheral wall surface (N / mm ² )
δ: Out-of-plane deformation (mm) allowed at the center in the height direction of the peripheral wall

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