WO2017162542A1

WO2017162542A1 - Switchgear cabinet having improved cooling as a result of a zigzag-shaped or ondulated wall

Info

Publication number: WO2017162542A1
Application number: PCT/EP2017/056458
Authority: WO
Inventors: Laetitia DEPRE
Original assignee: Eaton Industries (Austria) Gmbh
Priority date: 2016-03-24
Filing date: 2017-03-17
Publication date: 2017-09-28
Also published as: DE102016105634A1

Abstract

Disclosed is a switchgear cabinet (1, 1a, 1b) comprising a housing (2, 6a..6g, 7, 8), at least one switching device (3) in the housing (2, 6a..6g, 7, 8), and current conductors (4, 5) that are electrically connected to the at least one switching device (3). According to the invention, at least one wall (6a..6g) of the housing (2, 6a..6g, 7, 8) has an ondulated or zigzag-shaped cross-section.

Description

CABINET WITH IMPROVED COOLING BY

ZIGZACK OR WAVY WALL

TECHNICAL AREA

The invention relates to a control cabinet which comprises a housing and at least one switching device arranged in the housing and thus electrically connected current conductors, in particular bare conductors.

STATE OF THE ART

A cabinet of the type mentioned is basically known. In general, such a cabinet on a frame or a frame in which said

Conductor especially housed in the form of busbars ("bus bars") and are electrically connected to the also arranged in the frame / frame switching devices. In a manner known per se, such a cabinet serves, for example, the distribution of electrical energy and / or the control of systems and motors. In addition to the aforementioned switching devices can therefore also other devices in

Cabinet be housed. To protect the system or the persons serving them, control cabinets are usually lined on all sides, for example with the help of sheet metal walls or panels. This has the consequence that the said devices are operated within a substantially closed volume and waste heat can often not be dissipated sufficiently without further measures. In order to improve the heat dissipation, for example, ventilation slots, in particular in connection with fans, and / or cooling fins may be provided. The disadvantage of this is the comparatively complex production and in the case of the ventilation slots, the opening of the control cabinet wall and thus

accompanied by the increased potential risk of electric shock. Cooling fins are either welded to the housing wall, which is problematic in terms of a delay of the component, or screwed onto the housing wall, which is manufacturing technically complex because of the many holes. DISCLOSURE OF THE INVENTION

It is therefore an object of the invention to provide an improved cabinet. In particular, the cabinet cooling should be produced by simple technical means and ensure good electrical insulation.

This object is achieved with a control cabinet of the type mentioned, in which at least one wall of the housing has a wavy or zigzag extending cross-section.

The proposed measures improve both the thermal and the mechanical properties of the cabinet. On the one hand, the special shape of the housing wall leads to an enlarged surface thereof and thus to an improved cooling effect, on the other hand, the housing wall is also more stable due to the selected cross-sectional shape, whereby the control cabinet is more stable or a frame / frame of the same can be made more fragile. Advantageously, openings in the housing wall can thus be avoided or at least reduced / reduced, so that the electrical insulation of the control cabinet takes place at a high level. Similarly, blowers can be avoided or at least reduced in size. Along with this, the (parasitic) energy consumption of the control cabinet also decreases. Finally, the housing wall can be easily manufactured, in particular in a production step, for example by bending or pressing. The drilling holes for the installation of cooling fins or the welding of cooling fins associated with the problematic thermal distortion can be omitted.

By "undulating" running cross-sections, in particular rounded shapes or shapes composed of round sections can be understood. For example, the cross-section may be sinusoidal based on periodic signals. Of course, the cross section can also be composed of parabolic or elliptical sections.

Under "zigzag" running cross sections can in particular angular

or forms composed of straight sections are understood. For example, the cross section may be based on periodic signals in particular triangular, sawtooth, rectangular or trapezoidal.

Of course, mixed forms of said forms are possible, that is, the cross section may also be composed of straight and round sections. In particular, the corners of the "zigzag" extending cross sections can be rounded. Generally, it can be said that the cross section is not straight but has a periodically recurring shape. In particular, said wall of the housing has the shape of a prism with one of the above-mentioned forms as

Floor space.

Further advantageous embodiments and modifications of the invention will become apparent from the dependent claims and from the description in conjunction with the figures.

It is favorable if said wall is formed as a rear wall and

is arranged opposite a door of the cabinet. As a result, the cooling effect is maintained, even if several cabinets are lined up side by side. In addition, due to the other smooth walls, a cleaning of the cabinet can be done easily.

It is advantageous if the said cross-section is in a horizontal plane when the switchgear cabinet is ready for operation and generators which are normal to the cross-section are vertically aligned. That is, the longitudinal direction of the waves is aligned vertically. On the one hand, a high mechanical stability is thereby achieved, in particular with a bending load about a horizontal axis, on the other hand, a substantially laminar vertically from bottom to top extending air flow can be formed, which favors the heat transfer of the cabinet to the environment by convection.

But it is also advantageous if said cross-section is in the operational control cabinet in a vertical plane and are aligned horizontally on the cross-section normal standing generators. That is, the longitudinal direction of the waves is aligned horizontally. On the one hand, this also achieves a high mechanical stability, in particular with a bending load of one vertical axis, on the other hand form in a vertically from bottom to top extending air flow vortex, which can also promote the heat transfer of the cabinet to the environment by convection.

It is particularly advantageous if a wavelength of the wave-shaped / zigzag-running cross-section is in a range of 1 mm to 50 mm inclusive. The term "wavelength" is to be seen on the basis of periodic signals and designates in cross section the smallest longitudinal distance between two points which are at the same height. The cross-sectional profile is repeated accordingly at the distance of

Wavelength. A distance in a range of inclusive 1 mm up to and including 50 mm has been found to be particularly advantageous for the thermal and mechanical

Properties, in particular the lower limit of the specified range.

It is also particularly advantageous if a height of the cross section is in a range of 1 mm to 20 mm inclusive. Based on periodic signals, the height of the cross section is the "peak-to-peak value" or twice the "amplitude". A cross-sectional height in a range of from 1 mm to 20 mm inclusive has proven to be particularly advantageous for the thermal and mechanical

Properties, in particular the lower limit of the specified range.

It is also favorable if the at least one wall is made of metal, for example made of sheet steel. On the one hand, the housing wall can thereby be easily manufactured, for example by swaging, on the other hand, by the use of the metal and a good heat conduction from the interior of the

Cabinet achieved to the environment.

Furthermore, it is advantageous if at least 90% of the at least one wall has a wave-shaped or zigzag-running cross-section. In this way, a significant improvement in the cooling effect and the mechanical properties can be achieved.

Finally, it is also advantageous if the undulating or zigzag cross section extends over at least two periods. This also contributes to a significant improvement in the cooling effect and the mechanical properties of the Cabinet at. The term "period" is again to be seen in accordance with periodic signals.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will be explained in more detail with reference to the exemplary embodiments indicated in the schematic figure of the drawing. It shows:

1 shows an exemplary cabinet in front view.

Fig. 2 shows an exemplary cabinet with vertically in the rear wall

running waves seen from obliquely behind;

Fig. 3 shows an exemplary cabinet with horizontally in the rear wall

running waves seen from obliquely behind;

Fig. 4 shows the triangular cross-section of the rear wall of

Switch cabinets of Figures 2 and 3;

5 shows a trapezoidally extending cross section of a control cabinet wall;

6 shows a rectangular cross-section of a control cabinet wall;

7 shows a sawtooth-shaped cross-section of a control cabinet wall;

8 shows a sinusoidally extending cross section of a control cabinet wall and

Fig. 9 is a composite of straight pieces and curved pieces course of a cross section of a cabinet wall.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows an exemplary cabinet 1 in front view. The switchgear cabinet 1 comprises a frame or a frame 2 and a switching device 3 arranged in the frame 2. The switchgear 3 can be used, for example, as a circuit breaker,

Disconnector or circuit breaker may be formed. In the cabinet 1 (bare) power conductors 4 and 5 are also arranged (so-called "bus bars"), which are electrically connected to the switching device 3. The current conductors 4 extend vertically, the current conductors 5 horizontally. In addition, the current conductors 4, 5 for different Voltage potentials provided. For example only, the current conductors 4 and 5 are assigned to the phases LI, L2 and L3 of a three-phase system. Of course, a neutral could be provided and of course the current conductors 4 and 5 could be assigned to other voltage potentials.

In known manner, such a cabinet 1 is for example the

Distribution of electrical energy and / or the control of plants and engines. In addition to the aforementioned switching devices 3, therefore, even more switching devices 3 and / or other devices can be accommodated. For the protection of the cabinet 1 and the persons serving it this is covered on all sides, for example by means of sheet metal walls or panels. In Fig. 1, however, this walls / panels is removed to look into the interior of the

Release control cabinet 1. The cabinet 1 may be closed at the front, in particular with a door.

Fig. 2 shows an exemplary cabinet la from obliquely behind, in which the housing walls are mounted. In the example shown, the rear wall 6a of the housing has a wavy or zigzagging cross section. The

Side walls 7 and the roof 8, however, are smooth (but may have beads for reinforcement). The mentioned cross-section is ready for operation

Cabinet la in a horizontal plane X, and on the cross-section normal standing generators q are aligned vertically. The rear wall 6a can in particular be arranged opposite a control cabinet door (not visible in FIG. 2) and made of metal, for example bent or pressed. The housing of the cabinet la comprises in this example the rear wall 6a, the side walls 7, the roof 8, the door (not shown) and the frame, respectively, the frame 2.

The proposed measures both the thermal and the mechanical properties of the cabinet la are improved. On the one hand, the special shape of the housing wall 6a leads to an enlarged surface thereof and thus to an improved cooling effect; on the other hand, the housing wall 6a is also more stable due to the selected cross-sectional shape, as a result of which the control cabinet la becomes more stable or the frame / frame 2 can be made more fragile. Advantageously, openings in the housing wall 6a can thus be avoided or at least reduced / reduced, so that the electrical insulation of the control cabinet 1a takes place at a high level. Similarly, blowers can be avoided or at least reduced in size. Along with this, the (parasitic)

Energy consumption of the cabinet la. The housing wall 6a can also be easily manufactured, in particular in a production step, for example by bending or pressing. The drilling of holes for the mounting of cooling fins or the welding of cooling fins can be omitted.

It is favorable if said wall 6a, as shown in FIG. 2, is designed as a rear wall and is arranged opposite a door of the control cabinet 1a. As a result, the cooling effect is maintained, even if several cabinets la are lined up side by side. In addition, due to the other smooth walls and a cleaning of the cabinet la can be done in a simple manner.

By the orientation of the generators q is in this embodiment

reaches a high mechanical stability especially at a bending stress about a horizontal axis. In addition, a substantially laminar vertically from bottom to top extending air flow can form, which

Heat output of the cabinet la favors the environment by convection. In addition, by using metal for the rear wall 6a, a good heat conduction from the interior of the cabinet la to the environment is achieved.

The vertical orientation of the generators q is by no means the only conceivable possibility. Rather, it is also conceivable that the wave-shaped or zigzag-running cross-section of the switch cabinet lb ready for operation lies in a vertical plane Y and the generators q which are normal to the cross-section are aligned horizontally, as shown in FIG. That is, the longitudinal direction of the waves is aligned horizontally. As a result, a high mechanical stability is achieved, in particular in the case of a bending load about a vertical axis. In addition, they form in a vertical from bottom to top

Air flow vortex, which can also promote the heat transfer of the cabinet la to the environment by convection. FIG. 4 now shows in detail the cross-section used in FIGS. 2 and 3 for the rear wall 6a, 6b. Specifically, it is a triangular, zigzag cross section. This can be made very easy.

Alternatively, a zigzag-extending cross section may also be trapezoidal, as shown in FIG. 5, rectangular (see FIG. 6) or for example also sawtooth-shaped (see FIG. 7). Fig. 8 shows a representative of the undulating

extending cross sections, here specifically with sinusoidal course. Of course, the cross section may also be composed of other curve segments, for example parabolas, elliptical segments or hyperbolas. It is also conceivable that the cross section of straight sections and curve segments is composed, as shown by the example of FIG. 9.

In general, it should be noted that sharp corners in zigzagging cross sections are usually not produced and not desirable. In particular, when bending from the sheet minimum radii must be adhered to, so as not to risk breaking the material. The boundaries between zigzagging respectively out

Straight pieces composite cross-sections and wave-shaped respectively composed of curved sections cross sections are therefore fluent. As a rule, due to the technically caused corner radii a mixed form is present.

As mentioned, the special shape of the housing walls 6a..6g leads to an increased surface area and thus to a larger surface area compared to the prior art

improved cooling effect. Particularly great is the gain in the examples shown in Figures 6, 8 and 9, slightly smaller in the examples shown in Figures 4, 5 and 7.

It is particularly advantageous in accordance with periodic signals when a

"Wavelength" 1 of the undulating / zigzag cross section is in a range of 1 to 50 mm inclusive. The "wavelength" 1 denotes in cross section the smallest longitudinal distance between two points which are at the same height. The

Cross-sectional profile is repeated accordingly at a distance of wavelength 1 (see Fig. 4). The specified range has been found to be particularly advantageous for the thermal and mechanical properties, in particular its lower limit. It is also particularly advantageous if a height y of the cross section is in a range from 1 to 20 mm inclusive. Based on periodic signals, the height h of the cross section is the "peak-to-peak value" or the double "amplitude" (see FIG. 4). The specified range has been found to be particularly advantageous for the thermal and mechanical properties, in particular its lower limit.

Hereinafter, the improved heat dissipation is calculated on a concrete example, in particular, for a rear wall 6a having a triangular cross section (see FIGS. 2 and 4). For simplicity, only the

Heat transfer calculated by convection. The heat radiation is neglected because of its small share of about 20% -30% of the output power.

For the calculation, an interior temperature of Ti = 343 ° K, a

External temperature of Ta = 299 ° C and a back wall temperature of Ts = 317 ° K assumed, or these values are obtained from a simulation. Because of the only small thickness of the back wall 6a, 6b of 2 mm, the temperature Ts is assumed to be constant over the entire cross section. Of the

Heat transfer coefficient h for vertical panels with a height> 30 cm is h = 1,78 ^■ AT ⁰ ^'25 [W / m ^{2 ■} K]

The heat flow Q is thus calculated to

Q = h - A - AT [W]

Q = 1.78 ^■ A ^■ (Ti - Ts) ⁰ ^{'25 ■} (Ti - Ts) + 1.78 ^■ A ^■ (Ts - Ta) ⁰ ' ^{25 ■} (Ts - Ta) Q = 1.78 ^■ A ^■ [(Ti - Ts) ¹ ^'25 + (Ts - Γα) ¹ · ²⁵ ] Q = 1.78 ^■ A ^■ [(343 - 317) ¹ · ²⁵ + (317 - 299) ¹ · ²⁵ ] Q = 1 , 78 - A ^■ [58.71 + 37.08] Q = 170.5 ^■ .4 [W]

The length of a straight section of the cross section 6a is calculated at y = 10mm and 1 = 10mm

s = 11.18 mm

The relative gain r of the area A is thus

11.18

r = 1

10/2 r = + 123%

The absolute gain of the heat flow AQ is at a height of the cabinet of H = 2m and a width of B = Im thus

AQ = 170.5 - r ^■ A

AQ = 170.5 - r - H - B

AQ = 170.5 ^■ 1.23 - 2 - 1

AQ = 419 [W]

This means that with the same volume of cabinet la an additional power of 419 W can be delivered to the environment, which, as mentioned, corresponds to a relative gain of + 123%.

In the example shown in FIG. 6, the improvement of the mechanical stability is also subsequently calculated, specifically the axial area moment of inertia I _x about an axis of symmetry running horizontally in FIG. 6. The

Area moment of inertia I _x for a rectangle

_b - h ³ where b is the width and h here the height of said rectangle. Due to Steiner's theorem, b-hr results from a displacement of the rectangle from the x-axis

+ b ^■ h - y.

12 where y _s indicates the centroid distance of the rectangle to the x axis. For 1 = 10mm and a Blechstäre s = 2 mm results in an even back wall an axial

Area moment of inertia I _x of b - h ³ l - s ³ 10 - 2 ^Ξ

6,67 mm ⁴

12 12 12

For a "wavelength" 1 = 10 mm of the cross section 6d, on the other hand, at a height y = 10 mm y ³ (/ - 2 s) - s ³ results

+ + (Z - 2s) ^■ s ^■ y

12 12

2 ^■ 10 ³ 6 ^■ 2 ³

+ - + 6 ^■ 2 ^■ 4 ² 725 mm ⁴

12 12

The axial moment of inertia I _x is thus increased to about 109 times.

As could be shown, both the thermal and the mechanical properties of the control cabinet 1, 1a, 1b are significantly improved by the proposed measure.

In the examples according to FIGS. 2 and 3, the rear walls 6a, 6b have a wavy or zigzagging cross section over their entire surface. In principle, however, it is also conceivable that the structure shown is interrupted or does not extend to the edge of the rear wall 6a, 6b, for example at

To attach fasteners or the like. In any case, it is advantageous if at least 90% of the at least one wall 6a, 6b have a wave-shaped or zigzag-shaped cross-section, as a result of which the above-mentioned improvements are particularly evident. It is cheap in this

Correlation also when the undulating or zigzag running

Cross section extends over at least two periods. Finally, it is noted that the illustrated cabinet 1, la, lb respectively whose components are not necessarily shown to scale and therefore may have other proportions. Furthermore, a control cabinet 1, la, lb also comprise more or fewer components than shown. Location information (eg "top", "bottom", "left", "right", etc.) are based on the respective figure described and are mutatis mutandis adapt to a new position to the new situation. Finally, it is noted that the above refinements and developments of the invention can be combined in any desired manner.

Claims

claims

1. control cabinet (1, la, lb), comprising

a housing (2, 6a..6g, 7, 8),

at least one switching device (3) arranged in the housing (2, 6a..6g, 7, 8) and electrically connected current conductors (4, 5),

characterized in that

at least one wall (6a..6g) of the housing (2, 6a..6g, 7, 8) has a wave-shaped or zigzagging cross-section.

2. Switchgear cabinet (1, la, lb) according to claim 1, characterized in that said wall (6a..6g) formed as a rear wall and opposite a door of the cabinet (1, la, lb) is arranged.

3. Switchgear cabinet (1, la, lb) according to claim 1 or 2, characterized in that said cross section in the ready-to-use control cabinet (1, la, lb) in a horizontal plane (X) and normal to the cross-section standing generator (q ) are vertically aligned.

4. switchgear cabinet (1, la, lb) according to claim 1 or 2, characterized in that said cross section in the ready-to-use control cabinet (1, la, lb) in a vertical plane (Y) and on the cross-section normal standing generatrix (q ) are aligned horizontally.

5. control cabinet (1, la, lb) according to one of claims 1 to 4, characterized

characterized in that a wavelength (1) of the undulating / zigzag cross section is in a range of 1 mm to 50 mm inclusive.

6. Switching cabinet (1, la, lb) according to one of claims 1 to 5, characterized in that a height (y) of the cross section is in a range of 1 mm to 20 mm inclusive.

7. switchgear cabinet (1, la, lb) according to one of claims 1 to 6, characterized

in that the at least one wall (6a..6g) is made of metal.

8. Switching cabinet (1, la, lb) according to one of claims 1 to 7, characterized

in that at least 90% of the at least one wall (6a..6g) has a wavy or zigzagging cross section.

9. switch cabinet (1, la, lb) according to one of claims 1 to 8, characterized

in that the undulating or zigzag cross section extends over at least two periods.