JPS6259882B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a tank for oil-filled electrical equipment whose body portion is constructed using a corrugated heat sink having a high cooling effect and made by continuously bending a thin steel plate. Figure 1 is a front view of a conventional oil-immersed transformer using this type of tank, Figure 2 is a cross-sectional view of the tank body,
FIG. 3 is an enlarged cross-sectional view of the corner of the tank. The tank 1 shown in these figures has upper and lower ends welded between each side of an upper frame body 5 provided with a flange for attaching a tank cover 4 and a lower frame body 6 to which a tank bottom plate is attached. The body is constructed by stretching a corrugated heat sink 2 having a large number of closed fin-like protrusions 3, and each corner 7 of the body is covered with a corrugated heat sink 2.
It is constructed by bending the corrugated heat sink 2 at right angles or by joining the ends of the corrugated heat sink 2 by welding. Tanks using this type of corrugated heat sink are mainly used for medium and small oil-immersed transformers, and are useful for reducing the size and weight of transformers, but when applied to transformers with larger capacity, etc. For the reasons stated above, there are restrictions on the height and number of fin-like overhangs of the corrugated heat sink.
There was a limit to miniaturization and weight reduction. In other words, this type of tank has insulating oil sealed inside to cool and insulate the electrical equipment body, and depending on the application, it is sealed with a space for pressure adjustment, so when the equipment is in use, the tank body is The static pressure caused by the head of the insulating oil and the dynamic pressure caused by the volumetric expansion of the internal air as the temperature rises act. In FIG. 3, the state in which the fin-like protruding portions of the corrugated heat sink in a conventional tank are deformed due to these internal pressures is shown by two-dot chain lines. This deformation appears symmetrically as δ ₁ with respect to point A in the abdomens 3 _a on opposite sides of the adjacent fin-like overhangs 3, and the amount of deformation is relatively small. However, corner 7
A larger deformation than δ ₁ , such as δ 2, occurs in the abdomen 3 _b facing the corner 7 side of the fin-like overhang ₃ located near . For example, plate thickness t = 1.2 mm, height of overhang (wave height) h = 315 mm, width of overhang (wave width) b = 10.4 mm, interval between overhangs (pitch) l ₁ =
37.5mm, distance from corner 7 to nearest overhang l ₂ =
When an internal pressure of 0.1 Kg/cm ² was applied to a tank using a corrugated heat sink with a vertical length of 50 mm and an overhang length l ₃ = 1524 mm, deformations of δ ₁ = 10 mm and δ ₂ = 20 mm were observed. Ta. The deformation of this fin-like overhang increases as the internal pressure increases, and eventually exceeds the elastic limit of the material and causes permanent deformation. Therefore, in such a tank structure in which the amounts of deformation of δ ₁ and δ ₂ are different, the allowable internal pressure etc. must be determined based on the value of δ ₂ . The reason why the amount of deformation of the fin-shaped protruding portion 3 near the corner is δ ₂ >δ ₁ can be explained as follows. As shown in FIG. 4, when an internal pressure of p per unit area is applied to each _part of the corrugated heat sink 2, _M =p·
A force of a (a: pressure receiving area) acts. Considering the moment around the center point A of the force M acting on the opposing abdomens _3a of adjacent fin-like overhangs 3,
The moment of force acting on these opposing abdomens _3a exerts a force in a direction that reduces the force M on the opposing abdomen _3a . For this reason, the abdomen 3 facing each other
The amount of deformation δ ₁ occurring in _a is symmetrical and relatively small, but the abdomen 3 _b facing the corner 7 side of the fin-like overhang 3 near the corner 7 has the opposing abdomen as described above. Since there is no force acting from 3 _a and the only force opposing M is the force N applied to the pressure receiving surface of the corrugated heat sink from the abdomen 3 _b to the corner 7, there is no balance as M>N, and as a result It is considered that δ ₂ > δ ₁ . This tendency becomes more pronounced as the ratio between the height h and the width b of the overhang increases. Distance from corner 7 to the nearest overhang
If l ₂ is increased to the same extent as the height h of the overhang, δ
₂ ≒ δ ₁ , but in order to do so, the number of projecting portions 3 must be reduced and the heat dissipation area must be sacrificed. In this way, in oil-filled electrical equipment tanks that use conventional corrugated heat sinks, there are restrictions on the height and number of fin-like protruding parts of the corrugated heat sinks, so the generated heat loss is limited compared to the size of the contents. Large to medium-sized equipment (as an example, an oil-immersed self-cooling transformer is 750kVA or more)
In order to secure the required cooling area, the length of the fin-shaped overhang part _L3 is increased, and if necessary for cooling, the dimensions x and y of the tank body shown in Fig. 2 are increased to create a corrugated heat sink. The installation space for the tank must be increased, resulting in an increase in the size and weight of the tank, making economical design difficult. As a countermeasure for this problem, the inventors have constructed joint plates 8 at each corner of the tank body with the same shape and size as the fin-like protruding parts 3 of the corrugated heat sink 2, as shown in FIG.
are arranged symmetrically with respect to the two sides of the body, and the perpendicular extensions 9 _a and 9 _b of the joint plate 8 are joined to the corrugated heat sink 2 at welded parts 10 _a and 10 _b , respectively. This was proposed previously (Patent Application No. 1983-21797). According to this configuration, when internal pressure is applied to the tank, the fins as shown in FIG. It is possible to eliminate the unbalance between the deformation amounts δ ₁ and δ ₂ of the shaped overhanging portions, resulting in a tank structure that is balanced in terms of strength, and also has the effect of increasing the heat radiation area because the joint plate 8 serves as a heat radiation plate. However, it was not sufficient in terms of effective use of the dead space in the corner of the tank. In view of the above points, an object of the present invention is to provide a tank for oil-filled electrical equipment that is balanced in terms of strength, has no dead space, and can be made smaller and lighter. Embodiments of the present invention shown in FIGS. 6 to 12 will be described below. As shown in detail in FIG. 11, the framework of the tank 11 according to the present invention includes an upper frame 12, a lower frame 1,
3. It consists of upper and lower joint plate parts 14, 15, a support column 16, and a base member 17. The upper frame 12 is formed by combining L-shaped members into a frame shape consisting of long sides and short sides to form a flange 18 that serves as a mounting seat for the tank cover, and has a flange 18 at each corner extending parallel to the long side. The upper joint plate portion 14 is formed by an extension of the long side L-shaped member. The lower frame body 13 is formed by bending a steel plate into a frame shape consisting of long sides and short sides, and a tank bottom plate 19 is integrally attached to the bottom frame body 13. At each corner, there is a frame having the same thickness as the upper joint plate part 14. The plates are joined by welding to form a lower joint plate portion 15 extending parallel to the long side. This lower frame body 13 is placed on a base member 17 made of a combination of U-shaped steels. The column 16 having an L-shaped cross section is connected so that its long side is parallel to the short sides of the upper and lower frames 12 and 13, and its short side is located on the extension of the long sides of the upper and lower frames 12 and 13. The tips of the plate parts 14 and 15 are bonded using a solution, and the lower ends are fixed onto the base member 17 by welding. The cross-sectional shape of the support column 16 is not limited to an L-shape, but may be any shape having two side surfaces that are overlapped and joined to side portions 24 and 25 of corrugated heat sinks 20 and 21, which will be described later. The corrugated heat sinks 20 and 21 are placed around the four sides of the frame constructed in this manner to constitute the tank body. The corrugated heat sinks 20 and 21 have a large number of fin-like protruding portions 22 and 23 formed by bending a thin steel plate into a corrugated shape, closing the upper and lower ends of the corrugated portions, and sealing them by welding.
Side portions 24 and 25 are formed at both left and right ends, respectively, and are bent approximately parallel to the fin-like protruding portions 22 and 23. As shown in FIGS. 6 to 8, the corrugated heat sink 20 on two of the four sides has a length equal to the length of the long side of the upper and lower frames 12, 13 plus the length l of the upper and lower joint plate parts 14, 15. difference
It has _a horizontal width _equal to They are overlapped and joined in an oil-tight manner by welding, and the left and right side portions 24 are overlapped with the long side surfaces of the column 16, and their three edges are joined in an oil-tight manner by welding. The other two corrugated heat sinks 21 are the upper and lower frames 12 and 1.
The upper and lower ends are overlapped with the short sides of the upper and lower frames 12 and 13 and are oil-tightly joined by welding, and the three ends of the left and right sides 25 are The edge is welded and oil-tightly joined to the other side surface of the upper and lower joint plate parts 14, 15 and the short side side surface of the support column 16 formed on the same surface. FIG. 9 is a sectional view of the tank body configured in this manner taken along the line A-A in FIG. 7, and FIG. 10 is a sectional view taken along the line A-B in FIG. In the cross-sectional view taken along the line, 26 _a and 26 _b in the figure show welds between the corrugated heat sinks 20 and 21 and the upper and lower joints 14 and 15, and 26 _c and 26 _d show welds between the corrugated heat sinks 20 and 21 and the struts 16. It shows the part. According to the above configuration, as seen in FIGS. 9 and 10, upper and lower joint plate portions 1 are provided at each corner of the tank 11.
An oil pipe 27 is formed, which is surrounded on three sides by the support 16 and the extension part 20 _b of the corrugated heat sink 20 and covered on both sides by the extension part 20 b of the corrugated heat sink 20 and the side part 25 of the corrugated heat sink 21. The oil in the tank passes through the oil pipe 27 into the fin-like projection 22 formed on the extension 20 _b of the corrugated heat sink 20 and on the side portion 24 of the corrugated heat sink 20.
It flows into the gap between the and support column 16 as shown by the arrow in FIG. For this reason, the extension portion 20 of the corrugated heat sink 20 has the same external dimensions as the conventional tank shown in FIGS. 1 to 3.
The heat dissipation area increases by an amount corresponding to _b , and the dead space in the corner of the tank, which conventional tanks had, can be utilized to the maximum as a heat dissipation surface. In addition, when this tank 11 receives internal pressure, a force corresponding to M shown in FIG.
4 and 25, the moment of this force acts on the abdomens 22 b , 23 _b of the fin-like protruding portions 22 , 23 facing the side portions 24 , ₂₅ in opposition to M. Similarly, the abdomens 22 _b of the fin-like protruding parts 22 and 23 facing the side parts 24 and 25 are also
23 An opposing force acts from _b . As a result, a nearly symmetrical deformation (bulge) occurs in the abdomens of the fin-like overhangs 22 and 23 and the side parts 24 and 25, and the amount of deformation δ ₂ is determined by the direction of the fin-like overhangs. The amount of deformation δ ₁ occurring in the fitted abdomens 22 _a and 23 _a is approximately the same (δ ₂ ≈ δ ₁ ), and is significantly smaller than in the case where the side portions 24 and 25 are not provided. This results in
It is possible to obtain a tank with balanced strength without the unbalanced amount of deformation as in the past, and to reduce the restrictions from the strength aspect on the height and number of fin-like overhangs, and to increase the heat dissipation area. becomes possible. Furthermore, according to the above structure, since the highly rigid support column 16 is provided on the outermost side of the tank, the support column 16 is provided with a hanging ear part 28 and a pull hole 29 for pulling the roller, and the base member 17 is fixed to the support column. By providing the jack receiving part 30 under the tank, there is no unbalanced force applied to the corrugated heat sink of the tank body when equipment is lifted, rolled, or pushed up by jacks, which can cause oil leakage. It can prevent cracking of welding beats. The support column 16 extends upward from the upper frame body 12, and has a hanging ear portion 28 at its upper end. This way, the first
As shown in Figure 2, when the shackle 32 of the hanging rope 31 is hooked onto the hanging ear part 28, the hanging rope and shackle come into contact with the upper structure such as the tank cover 33, the bushings attached thereto, and the terminal box. This can be avoided. As shown in FIG. 1, in a conventional tank in which a hanging ear part 34 is provided on the upper frame body 5, it is necessary to increase the height m of the upper frame body 5 in order to hang a rope on the hanging ear part 33. However, if the hanging ear part 28 is provided at the upper end of the support column 16 as described above, the height m of the frame 12 can be made smaller (to give an example of the dimension m, compared to the conventional
Although it was 110 mm, in the present invention, it may be about 50 mm). As a result, the height of the tank can be lowered and the rigidity of the frame 12 can be increased, so deformation of the upper frame 12 due to tank internal pressure is reduced, which occurs at the weld between the upper frame and the corrugated heat sink. It is possible to reduce stress and increase the pressure resistance of the tank. The jack receiving portion 30 is formed by cutting out a part of the ground surface of the base member 17 in order to improve workability. The dimensions and weight of equipment using the conventional tank and the tank according to the present invention shown in Figures 1 to 3 are summarized in three phases.
The table below shows a comparison example of 1000kVA oil-immersed transformers.

[Table] As explained above, according to the present invention, it is possible to eliminate the unbalance in the deformation of the corrugated heat sink due to the internal pressure of the tank, reduce the constraints on the height and number of fin-like protrusions from the viewpoint of strength, and We placed corrugated heat sinks in the dead spaces at the four corners of the conventional tanks shown in Figures 1 to 3 to increase the heat radiation area, making it suitable for tanks for medium to large capacity oil-filled electrical equipment. By effectively utilizing this type of corrugated heat sink, equipment can be made smaller and lighter.

[Brief explanation of the drawing]

Figure 1 is a front view of a transformer with a conventional tank using a corrugated heat sink, Figure 2 is a cross-sectional view of the body of a conventional tank, Figure 3 is an enlarged view of its main parts, and Figure 4 is a conventional transformer. Explanatory diagram of deformation due to internal pressure of mold tank, 5th
The figures are cross-sectional views of main parts showing other conventional examples of tanks for oil-filled electrical equipment using corrugated heat sinks, Figures 6 and 7.
8 are respectively a front view, a side view, and a plan view of a tank for oil-filled electrical equipment according to the present invention, FIG.
The figure is a sectional view of the main part taken along line B-B in figure 6 and line C-C in figure 9, figure 11 is a perspective view showing a part of the tank framework and a corrugated heat sink, and figure 12 is a hanging ear part. It is a figure showing the usage state of. 11...Tank, 12...Upper frame, 13...
Lower frame body, 14... Upper joint plate part, 15... Lower joint plate part, 16... Support column, 17... Base member,
20, 21... Corrugated heat sink, 20 _b ... Extension of the wave heat sink 20, 22, 23... Fin-like protrusion,
24, 25... side parts of the corrugated heat sinks 20, 21,
27...oil pipe, 28...hanging part.

Claims (1)

[Scope of Claims] 1. An oil-immersed electrical appliance whose body portion is constructed by stretching a corrugated heat sink having a large number of fin-like protrusions closed at the upper and lower ends between each side of the upper frame and the lower frame. In equipment tanks, upper and lower joint plates extend from each corner of the upper frame body and the lower frame body in parallel with one side of both frames, and are joined to these joint plate parts and have their lower ends placed on top of the base member. A fixed support is provided, and the extended portion of the corrugated heat sink stretched between each side of both frames and the side portions bent approximately parallel to the fin-like overhang portions of the two joint plate portions are provided. The end edges are oil-tightly joined by overlapping one side and one side of the support column, and the corrugated heat sink is folded almost parallel to the fin-like protruding portion of the corrugated heat sink stretched between the other sides of both frames. A tank for oil-filled electrical equipment, characterized in that the bent side portion is stacked on the other side of the double joint plate portion and the other side of the support column, and the end edges are joined in an oil-tight manner. . 2. The tank for oil-filled electrical equipment according to claim 1, wherein the support column extends upward from the upper frame body and has a hanging ear portion at its upper end.