KR101944967B1 - Tank for liquid-filled transformers or inductors - Google Patents

Abstract

The present invention relates to an outer tank casing (2) comprising: a) an outer tank casing (2) comprising a bottom portion (3); b) an inner tank casing (5) enclosed by the outer tank casing (2) at a distance (4); the outer tank casing (2) and the inner tank casing (5) are formed of metal; c) is contained in the intermediate space (6) and is constrained by the inner surface (14) of the outer tank casing (2) and the inner surface (13) of the inner tank casing (5) D) a shearing force is transmitted between the outer tank casing 2 and the inner tank casing 5; e) the outer tank casing 2 and the inner tank casing 5 are made of plastic or polymer material 7, So that the transmission of the structure-borne sound, which occurs in the case of operation of the inner cylinder 10 arranged in the inner space 9 of the tank, between the plastic or polymer material and the inner surface 13, 14), characterized in that the adhesion of said plastic or polymeric material to the liquid-cooled transformer or the inductor is designed.

Description

[0001] TANK FOR LIQUID-FILLED TRANSFORMERS OR INDUCTORS [0002]

The present invention relates to tanks for liquid cooled transformers or inductors, such as those used in electric supply networks.

Electrical transformers or inductors, such as those used in electric power supply networks, typically include magnetic cores with electrical windings, which are insulated and cooled ) Liquid, e.g., a tank filled with oil.

The disadvantage here is that during operation of the transformer or inductor, the magnetism deforms the magnetic core and also the insulation and cooling liquid surrounding the forces acting on the individual conductors in the windings to vibrate. These vibrations propagate to the insulation and cooling liquids, causing unwanted sound radiation from the tank walls.

Passive measures for reducing operational sound absorption in transformers or inductors are known for a long time.

For example, the outer wall of the transformer tank is covered with plates made of flexible material, and the cavity located between the tank wall and the plate is sound-absorbed and / or sound- deadening materials are known from DE 23 09 564. In this case, it is recommended that foam-filling be performed by spraying a polyurethane foam material through individual injection openings into individual cells. Each cell is constrained by two metal reinforcements and, in each case, an outer plate connected via an elastic sealing strip. The disadvantage here is that the metal reinforcements and plates enlarge the external dimensions and thus interfere with the transport of power transformers, which often pass through the tunnels. In addition, the sound-absorbing device is composed of a plurality of discrete portions, which complicates its manufacture.

AT 23 77 31 proposes an air-borne sound deadening elastic transformer wall in which the polyurethane foam is formed to be sprayed or adhered in the form of plates on the exterior of the metal wall. In order to form a damping, a granular material such as steel particles or quartz sand is mixed into the polyurethane foam material. The disadvantage here is that the injected plastic is exposed to the environment without protection.

From GB 679 241 an arrangement for reducing noise emissions from a transformer is known, in which case the tank wall of the oil-filled transformer is surrounded by an additional housing on the outside. The intermediate space between the inner tank wall and the outer tank wall contains air. Again, this has the disadvantage that the external dimensions of the transformer are widened by sound absorbing measures.

So-called sandwich plate systems, in which the rigidity and strength of the metal structure can be increased by spraying an uncured plastic suitable for transferring shear forces between the metal layers between the two metal layers after curing, It is also known for the construction of ships or bridge decks. Structural laminates of this kind (also known as sandwich plate systems (SPS)) are described, for example, in WO 2003/101728, WO 01/32414 and WO 99/058 333.

Noise-deadening for high-power transformers and inductors is not always satisfactorily achieved. All passive approaches, including attaching sound-absorbing measures to the outside, can be carried out in the case of high-power mechanical devices, by transport, for example by a profile of a road or rail tunnel, Is limited by external dimensions.

It is an object of the present invention to disclose tanks for liquid charging transformers or inductors that are as small as possible without increasing the acoustic emissions of transformers or inductors during operation to an unacceptable size.

This object is achieved by means of a tank having the features of claim 1 and a method of manufacturing this kind of tank with the features of claim 10. Advantageous embodiments of the invention are defined in the respective dependent claims.

According to the basic idea of the present invention, a steel-plastic-steel sandwich construction known per se is used for the manufacture of double wall tanks. A double wall tank having this embodiment,

a) an outer tank casing comprising a bottom portion;

b) an inner tank casing enclosed by an outer tank casing at a distance - the outer tank casing and the inner tank casing are formed of metal;

c) a plastic or polymer material contained in the intermediate space and constrained by the inner surface of the outer tank casing and the inner surface of the inner tank casing and filling at least partially the intermediate space,

d) Shearing force is transmitted between the outer tank casing and the inner tank casing,

e) In order to prevent the transmission of structure-borne sound which occurs when an active part arranged in the inner space of the tank is operated between the outer tank casing and the inner tank casing,

Adhesion of the plastic or polymer material to the plastic or polymeric material and the plastic or polymeric material to the inner surface is designed.

The characteristics of the plastic arranged between the two tank walls are measured on the one hand to prevent conduction of the structural transmission sound from the outside space of the tank to the outside space. In operation, when the medium conductor, i.e. the soft magnetic core and the electric windings located thereon, are excited to excite the insulating liquid, these vibrations are attenuated when these vibrations reach the outer tank wall. As a result, the acoustic emissions from the transformer or inductor are low.

On the other hand, the connection between the plastic and the metal tank wall is such that a shear force can be transmitted between the inner tank wall and the outer tank wall. As a result, the sandwich structure also takes on a bearing function. As a result, the stiffeners can be designed smaller and occupy less space. Despite the sound absorption, the external dimensions are not enlarged. In contrast, since the internal stiffeners, which are normally required, can be designed to be smaller, the usable internal tank width also increases. This means that more space is available for the built-in components. A further advantage is that the tank can have a lighter weight overall overall.

To this end, during the manufacture of the tank, suitable plastics can be injected into the liquid (or not yet cured) state through the injection holes provided on the inner tank casing and / or the outer tank casing. Corresponding exit openings are provided for air leakage. In the cured state, the plastic applied in this manner between the walls of the double wall tanks functions in a manner similar to a box girder or an I-girder. This adheres strongly to the inner surfaces of the walls so that a shear force can be imparted, thereby contributing to the mechanical stability of the entire tank.

It may be advantageous that the thickness of the inner tank casing is smaller than the thickness of the outer tank casing.

It has now been found that it is advantageous that the thickness of the inner tank casing is half the thickness of the outer tank casing.

Depending on the composition and characteristics of the polymer material, the conduction of the structural transmission sound can be very effectively prevented if the distance between the inner tank casing and the inner surfaces of the outer tank casing is in the range of about 5 mm to 50 mm. Particularly preferably, in the case of a power transformer or power inductor, the thickness of the plastic or polymer material may be about 30 mm.

In the case of a transformer or an inductor, the insulation characteristics of the plastic between the walls of the tank are disadvantageous if the heat loss occurring during operation is diverted by the insulating liquid (e.g., transformer insulating liquid) into the outer space. To counteract this, it may be advantageous to add thermally conductive additives or similarly acting fillers to the plastic or polymer material of the sandwich structure. Here, it may also be advantageous that the cooling line is housed in an intermediate layer embedded in a plastic contained in the cooling system of the transformer or inductor.

In a preferred embodiment, the tank is formed of metal plates flush abutting the inner tank casing at substantially the same height, wherein the metal plates are welded to bars or other spacers Which are in turn welded to the inner surface of the outer tank casing. This embodiment is particularly desirable for the manufacture of power transformers. In the case of low electric power, it may also be advantageous that the inner tank is made in one piece and placed in a so-called pot-shaped outer tank, as an insert part.

BRIEF DESCRIPTION OF THE DRAWINGS For a further illustration of the present invention, the following sections of the specification refer to the drawings, from which those of further advantageous embodiments, details and improvements of the invention are shown by way of non-limiting exemplary embodiments . ≪ / RTI > The drawing is as follows.

1 is a tank according to an exemplary embodiment of the present invention in which an intermediate space formed between an inner tank casing and an outer tank casing is filled with plastic.
2 is a perspective view of the inner tank casing of FIG.
3 is a detailed view of "X" in Fig.
4 is a cross-sectional view taken from above, taken through the horizontal encircling reinforcement of FIG. 1, in a connection zone between the end side and the long side of the tank;
Figure 5 is a segment of the front wall of the tank viewed from the outside, shown in the vertical section.
Figure 6 is a segment of the front wall of the tank viewed from the inside, shown in the vertical section.
Figure 7 is a segment of the tank wall in the region of the pipe bushing through the tank wall, shown in the vertical section.
Figure 8 is a segment of the tank wall in the connector range for the insulating liquid, shown in the vertical section.
Figure 9 is a segment of a double walled tank showing the embedding of a cooling line in a plastic layer.

Fig. 1 shows a tank 1 having a casing constructed in the form of a double-walled tank. The double walls 2, 5 are formed by an outer tank casing 2 and an inner tank casing 5 arranged at a distance 4 from each other. Between these two casings 2 and 5 there is a circulating intermediate space 6 in which a plastic or polymer material 7 is filled according to the invention. The outer tank casing 2 continues tapering down to the bottom portion 3. The bottom part 3 is based on elastic supports 19 on a foundation. Electrical connections 23 (bushings) are arranged on a cover 8. Before the transformer / inductor is activated, a vacuum is typically generated in the internal space 9. In order to ensure the mechanical stability of the tank during vacuuming, various stiffeners are attached to the inside and outside of the tank; For clarity, FIG. 1 shows stiffeners 16 arranged externally only. The reinforcements 16 surround the tank casing. An insulating liquid (transformer oil) 24 is filled in the inner space 9 of the tank 1. The insulating liquid 24 surrounds the core 10 arranged in the inner space 9. [ In the case of a transformer, and in the case of an inductor, this core contains a soft magnetic core, around which an electrical winding is wound. For the sake of clarity, the middle tongue 10 is no longer described in detail in the drawing of Fig. As is known, during operation of a transformer or inductor, the magnetic core is excited to vibrations by magnetostriction. These vibrations propagate into the insulating liquid 24. During operation, the conductors of the electric windings are also excited, which also acts on the surrounding insulating liquid. Sound waves are formed in the insulating liquid 24 and also affect the inner casing 5. [ According to the present invention, a plastic having the property of inhibiting the propagation of the structure-borne sound on the outer casing 2 is now provided in the intermediate space 6. [ This reduces the excitations in the outer casing 2 and reduces the sound emissions.

Fig. 2 shows a perspective view of the inner tank casing 5. Fig. The inner casing 5 is formed by long sides and end sides facing each other. Each of these sides consists of discrete metal plates 18, which are facing each other at the joints of the plates. They are placed flush to one another and in each case form a level side surface or end face. During fabrication of the tanks according to the invention, these metal plates 18 are welded onto the bars 17 (see Fig. 4) and the bars are welded to the outer tank casing 2 Is welded to the inner surface (14). The access hatch 26, which is closed by the hatch cover 20 (see Fig. 5) in the assembled state of the tank, can be seen on one end side. An intermediate space (6) between the inner tank casing (2) and the outer tank casing (5) is bounded by the end bar (20).

3 shows an enlarged cross-sectional view of the detail of "X" in FIG. The thickness 12 of the wall of the outer tank casing 2 is larger than the thickness 11 of the wall of the inner tank casing 5. [ The adhesion of the plastic 7 to the inner surfaces 13 and 14 and the physical properties thereof are measured so that a shearing force can be transmitted between the two walls 5 and 2. Thus, the metal-plastic combination contributes to mechanical stability, which allows the stiffener 16, which prevents the implosion of the tank in the application of vacuum, to have smaller dimensions and thus occupy less space.

Fig. 4 shows a cross-sectional view taken through a horizontally orientated kinking stiffener 16. Fig. The plates 18 fastened to the bars 17 by the welded connection 25 can be seen. As already mentioned, the bars 17 are, in turn, welded on the outer tank casing 2. The ribs 28 are again reinforced in the stiffener 16 in turn.

5 shows a vertical section taken through the front wall of the tank viewed from the outside. It is possible to see the previously mentioned access hatch 27 perimeter region where the cavity formed by the double wall structures 2 and 5 is closed at the edge by the circulating end bar 20. [ It is also possible to see externally arranged ribs 28 and reinforcements 16.

Figure 6 shows a vertical section through the front wall of the tank viewed from the inside. This shows the lower reinforcing ribs 16 arranged on the outer side of the tank casing and the reinforcing ribs 28 arranged in the inner space 9 towards the metal plate 18 side. The double wall structure is continuous to the bottom portion 3 on the end wall. On the long side of the cuboid inner tank 5, the metal plate 18 ends and tapers from the transverse section to the bottom part 3.

Figure 7 shows a segment through the tank wall in the region of the pipe bushing 21 provided to discharge the insulating liquid. The intermediate space formed by the double wall structures (2, 5) is again closed by the end bar (20).

Figure 8 shows a segment of the tank wall in the region of the connector for the cooling system. A connecting pipe 22 is used to provide a connection to the heat exchanger, which is not shown in any further detail. Here, the sealing edge of the intermediate space is provided by the actual connecting pipe 22, not by a sealing strip.

Figure 9 shows an enlarged view of a preferred embodiment of a double wall tank. A filler 15 having a relatively better thermal conductivity is mixed into the plastic 7 so as to enable better heat dissipation from the internal space 9. [ This also shows an embodiment in which an insulating liquid (e.g., a transformer oil) flows through the cooling line 30 in addition to or as an alternative thereto. The cooling line 30 rests on the inner wall 13 of the inner tank casing 5 and is secured by clasps (not shown in more detail). Reference numeral 29 denotes an example of one of several injection openings or air exit openings 29 in the inner tank 5, which is closed again after introduction of the plastic 7 (see, for example, , By welding).

Among the procedures for manufacturing the tank according to the invention, at first, the external tank 2 is manufactured in a manner known per se. This is typically done by a welded structure. For the exemplary embodiment described above, in the next manufacturing step, the bars 17 are attached to the inner surface 14 of the outer tank casing 2. During this, the bars 17 are welded with a fillet weld on the outer tank casing 2 to a distance corresponding to the width of the metal plates 18 arranged on the inner surface 14. Thereafter, the metal plates 18 are successively disposed on the bars 17 and are also welded by fillet welding. This results in an internal tank casing 5 with matching flat end and side surfaces. Then, the plastic is now injected into the plastic through the injection holes 29; Thereafter, curing and subsequent adhesion of a fixed connection with the inner surfaces 13, 14 is followed. The injection holes and air outlet openings 29 are then closed, for example welded. The number and arrangement of injection openings / exit openings 29 required for penetration of the plastic is determined by the size and distance 4 of the metal plates 18.

Although the present invention has been illustrated and described in more detail by the preferred exemplary embodiments, the present invention is not limited to the disclosed examples, and other variations may be derived by those skilled in the art without departing from the protection scope of the present invention.

For example, the exemplary embodiment depicts an internal tank casing that does not have a bottom portion. Clearly, it is conceivable that the inner casing also has a bottom portion and the intermediate space is also filled with plastic. In the case of this embodiment, the two casings are similar to a pot and a matching pot container.

The plastics in the intermediate space need not include a single material but may obviously consist of different plastic layers and also plastic structural elements. It is also conceivable that the cover is embodied as a double wall structure.

1: tank
2: External tank casing
3: bottom portion
4: Distance
5: Internal tank casing
6: Intermediate space
7: Plastic or polymer material
8: Cover portion
9: Interior space
10: active part
11: Casing thickness of inner tank casing
12: Casing thickness of outer tank casing
13: inner surface of inner tank casing
14: inner surface of outer tank casing
15: filler
16: reinforcement
17: Bars
18: metal plate
19: Support
20: terminal bar
21: Outflow pipe
22: Connecting pipe (heat exchanger)
23: electrical connections (bushings)
24: insulating liquid (e.g., transformer oil)
25: Welded connection
26: Access hatch
27: Hatch cover
28: Lip
29: injection opening
30: Cooling line

Claims (14)

a) an outer tank casing (2) having a bottom part (3);
b) an inner tank casing (5) enclosed by the outer tank casing (2) at a distance (4); the outer tank casing (2) and the inner tank casing (5) are formed of metal;
c) is contained in an intermediate space (6) delimited by an inner surface (14) of the outer tank casing (2) and an inner surface (13) of the inner tank casing (5) , Plastic or polymer material (7) which fills the cavity
After curing, the plastic or polymer material 7 is connected to the inner surfaces 13,14 in a fixed manner by adhesion,
Characterized in that the inner tank casing (5) or the outer tank casing (2) comprises closable openings (29) for the injection of plastic or polymer material (7)
Liquid-cooled transformers or tanks for inductors.
The method according to claim 1,
Characterized in that the casing thickness (11) of the inner tank casing (5) is less than the casing thickness (12) of the outer tank casing (2)
Liquid-cooled transformers or tanks for inductors.
3. The method of claim 2,
Characterized in that the casing thickness (11) of the inner tank casing (5) is half the casing thickness (12) of the outer tank casing (2)
Liquid-cooled transformers or tanks for inductors.
4. The method according to any one of claims 1 to 3,
Characterized in that the distance (4) between the inner surfaces (13, 14) is selected in the range of 5 to 50 mm.
Liquid-cooled transformers or tanks for inductors.
4. The method according to any one of claims 1 to 3,
Characterized in that a line (30) carrying cooling medium is arranged in the intermediate space (6)
Liquid-cooled transformers or tanks for inductors.
6. The method of claim 5,
Characterized in that the plastic or polymer material (7) comprises a filler (15) having a lower thermal resistance than the plastic or polymer material (7)
Liquid-cooled transformers or tanks for inductors.
4. The method according to any one of claims 1 to 3,
The inner tank casing 5 is formed of metal plates 18 flush abutting at the same height,
Characterized in that the metal plates (18) are welded by means of a welded connection to the bars (17), which are in turn welded to the inner surface (14) of the outer tank casing (2)
Liquid-cooled transformers or tanks for inductors.
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