JPH0150084B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a natural convection cooling type tank for oil-filled electrical equipment.

In recent years, so-called corrugated tanks, in which corrugated fins are attached to the side plates of the tank, have come to be widely used in oil-filled electrical equipment, especially medium- and large-capacity oil-filled self-cooling transformers.

The corrugated fins installed at narrow pitches on the tank side plates of corrugated tanks help to reduce the size and weight of the tank due to their excellent heat dissipation effect, and their elastic deformation prevents volume changes in the insulating oil in the tank due to temperature changes. Since the tank has a pressure adjustment function to absorb oil, a special pressure adjustment device such as a conservator can be omitted as the tank is filled with insulating oil and sealed.

In this way, the adoption of corrugated tanks has played a major role in reducing the size and weight of oil-filled electrical equipment, simplifying maintenance management, and improving reliability.However, from the standpoint of cost reduction and increased resource utilization, the tank volume has been further reduced. ,
There is a need to conserve oil.

The present invention has been made in view of the above points,
The first purpose is to provide a corrugated tank for oil-filled electrical equipment that eliminates dead space at the corners of the tank and has a large oil-saving effect. To provide a corrugated tank for oil-filled electrical equipment which secures an inner width dimension of 1 and whose heat dissipation effect and pressure adjustment function are not impaired due to narrowing of the inner width of the corrugated fins. The third objective is to provide a corrugated tank for oil-filled electrical equipment that is inexpensive to manufacture and does not require special jigs or tools to process the corners of the tank or reduce the ease of assembling the tank. It is in.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a portion of the tank side plate of a corrugated tank. This tank side plate 1 has a large number of corrugated fins 2 made by continuously bending and forming a thin steel plate, and the upper and lower ends 2a and 2b of the corrugated fins 2 are closed and sealed by welding. In order to save the amount of oil and increase the cooling effect, the inner width w of the root portion of the corrugated fin 2 is made thin at 3 to 8 mm, and the height h is made larger than the inner width w. . The insulating oil in the tank, which has become warm by drawing heat from the heat-generating parts during the operation of electrical equipment, circulates inside the corrugated fins 2 by convection and radiates heat into the atmosphere. When rising, the corrugated fins 2 expand due to elastic deformation as indicated by broken lines 2' to absorb the pressure.

FIGS. 2 and 3 are plan views showing the shape of a conventionally used corrugated tank.

Figure 2 3 shows a general rectangular tank, whose four corners are right angles, so as shown in Figure 4, the iron core 5,
When the contents of an electrical device including the coil 6 are incorporated, the corner 7 with diagonal lines inside the tank becomes a dead space due to the relationship with the shape of the coil, which is uneconomical from the standpoint of saving oil.

FIG. 3 and 4 show an oil-saving tank whose four corners are rounded with radius R, and FIG. 5 shows an enlarged view of the corners of the tank side plate. If the corners of the tank are rounded to match the shape of the coil inside the electrical equipment, an oil-saving effect can be expected. Special jigs and tools are required to match the radius of curvature, which is disadvantageous in terms of cost if produced in small quantities. In addition, when assembling a tank by joining the bent tank side plate 1 with an upper flange and a tank bottom plate (not shown), the linear portions 1 on each side of the tank side plate 1
Since the boundaries between a and 1b and the curved portions 1c at the four corners are not constrained in any way in terms of mechanical strength, the dimensional deviations from the upper flange and the tank bottom plate are concentrated on the curved portions 1c at the four corners of the tank side plate, and the linear portion When there is a surplus in length of 1a and 1b, the internal width w of the originally narrow root portion of the corrugated fin 2 in the curved portion 1c is further narrowed as w' due to the surplus, and as a result, the corrugated fin 2 The flow of oil between the tank and the inside of the tank is obstructed, reducing the cooling effect. In addition, the waveform fin 2
The internal stress generated by the narrowing of the inner width acts to prevent elastic deformation of the corrugated fins 2 in response to an increase in internal pressure, and also reduces the pressure adjustment function of the corrugated fins. This tendency is particularly noticeable when corrugated fins with a high height h are provided on a tank with a small bending radius R at the corner, and spacers are inserted into the corrugated fin at the corner of the tank to ensure a predetermined internal width w. However, it is necessary to take measures such as removing the spacer after assembly.
As a result, the ease of assembling the tank decreases, leading to increased costs.

In order to solve the problems of the prior art, the present invention matches the outline of the tank side plate to the coil shape inside the electrical equipment, and at least each of the front, rear, left and right sides,
The tank side plate has a polygonal shape including linear sides located at the corners and intersecting the adjacent sides at obtuse angles, and corrugated fins are provided radially on each side. This is a corrugated tank.

FIGS. 6 and 7 show a tank structure according to an embodiment of the present invention.

Figure 6 is a diagram showing the tank side plate, upper flange, and tank bottom plate separated, and shows the tank side plate 11.
According to a known technique, a steel plate provided with a large number of corrugated fins 12 is bent between the corrugated fins and joined at at least one seam 13 along the entire circumference, so that the front, rear, left and right sides 11a, 11b are formed. ,11
c, 11d, and linear sides 11e, 11f, 11 located at their four corners and intersecting adjacent sides at obtuse angles.
g, 11h, and is shaped to have an octagonal outline with corrugated fins 12 arranged radially on each side. As shown in FIG. 1, the corrugated fins 12 have upper and lower ends closed together and sealed by welding.

The upper flange 14 and the tank bottom plate 15 also have the same octagonal outline as the tank side plate 11, and the upper and lower edges of the tank side plate 11 are joined by welding to the corresponding sides of the upper flange 14 and the tank bottom plate 15, respectively, to form a corrugated tank. Configure.

FIG. 7 is an enlarged view of the corner of the tank side plate 11. In this figure, the bending angle between the linear side 11e of the corner and the adjacent sides 11a, 11c is 135°, but the bending angle is is not limited to a specific angle. The length of the side 11e is selected so that a substantially constant distance necessary for insulation is maintained between each side of the tank side plate 11 including the side 11e and the coil inside the electrical device.

With this configuration, there is no dead space in the tank as shown with diagonal lines in FIG. 4, and the amount of oil can be saved significantly. Moreover,
Since the corrugated tank according to this embodiment has all straight sides, the tank side plate 11, upper flange 14, and tank bottom plate 15 can be bent using a normal bending machine regardless of the size of the tank. Unlike the conventional example shown in FIG. 3, special jigs and tools for rounding the corners of the tank are not required.

In addition, as shown in Fig. 7, the linear side 1 of the corner
The boundary between 1e and adjacent sides 11a and 11c is a fold 16,
17, so when assembling the tank, the tank side plate 11, upper flange 14, and tank bottom plate 1
If the folds 5 are aligned and joined, the dimensional error on each side of the tank side plate 11 will be absorbed by the expansion and contraction of each side, and as in the conventional example shown in FIG.
A predetermined inner width w can be ensured without causing the dimensional errors of 1a and 11c to be concentrated in the corners and narrowing the inner width of the corrugated fins 12 in the corners. Therefore, by using a corrugated fin with a height h, it is possible to exhibit good heat dissipation effect and pressure adjustment function of the corrugated fin around the entire circumference including the tank corner. There is no need for troublesome work such as inserting a spacer into the tank and removing the spacer after assembly, which improves the efficiency of tank assembly.

Further, according to this embodiment, by providing the straight sides 11e to 11h at the corners of the tank, the rigidity of the tank side plate and the upper flange is increased, and an effect of reinforcing the tank against internal pressure can be expected.

FIG. 8 shows an example of oil-filled electrical equipment using a corrugated tank according to this embodiment. After storing the contents of an electrical device having an iron core 5 and a coil 6 in a corrugated tank consisting of a tank side plate 11, an upper flange 14, and a tank bottom plate 15, a tank cover 20 with a primary bushing 18 and a secondary bushing 19 attached is attached to the upper flange 14. They are joined in an oil-tight manner by welding, and the tank is completely filled with insulating oil 21 from an oil filler port (not shown) of the tank cover 20, and the oil filler port is sealed, thereby sealing the inside of the tank. In such a completely sealed oil-type electric device, the absorption of the volume change of the insulating oil depends on the elastic deformation of the corrugated fins 12, so that the effects of the present invention can be best exhibited.

FIG. 9 shows another embodiment of the invention. In this embodiment, a recess 2 is formed with straight sides in the middle of the long side of the corrugated tank to match the shape of the coil inside the electrical equipment.
2 is provided to further enhance the oil saving effect, and the other configuration is the same as the previous embodiment.

From the above explanation, according to the present invention, it is possible to provide a corrugated tank for oil-filled electrical equipment that has a large oil-saving effect and is low cost, without impairing the good heat dissipation effect and pressure adjustment function unique to the corrugated tank. be understood.

[Brief explanation of drawings]

Figures 1 a and b are a perspective view and a cutaway plan view showing a part of a tank side plate used in a corrugated tank;
3 and 3 are plan views showing conventional examples of corrugated tanks, FIG. 4 is a corner sectional view of oil-filled electrical equipment using the corrugated tank shown in FIG. 2, and FIG. FIG. 6 is an exploded perspective view of a corrugated tank according to an embodiment of the present invention, FIG. 7 is an enlarged view of a corner of a tank side plate according to this embodiment, and FIG. 8 is an enlarged view of a corrugated tank according to this embodiment. FIG. 9 is a partially cutaway side view of the oil-filled electrical equipment used and a plan view showing another embodiment of the present invention. 11...Tank side plate, 11a, 11b, 11c,
11d...front, left, and right sides of tank side plate, 11e, 1
1f, 11g, 11h...straight edge at the corner, 12
...Corrugated fin, 14...Top flange, 15...Tank bottom plate, 16, 17...Folds of tank side plate.

Claims (1)

[Scope of Claims] 1. An upper flange, a tank bottom plate, and a heat dissipation fin that share a polygonal outline including at least front, rear, left, and right sides and straight sides located at the corners thereof and intersecting adjacent sides at obtuse angles. In the tank for electrical equipment, the side plate includes a plurality of continuously bent waveform fins, is bent to match the polygonal contour, and the bent portion is connected to the upper flange and the tank bottom plate. A tank for oil-filled electrical equipment, characterized in that the tank is joined so as to coincide with the corner of the tank, and is joined by a joint along the side.