Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K5/00—Casings, cabinets or drawers for electric apparatus
  • H05K5/02—Details
  • H05K5/0213—Venting apertures; Constructional details thereof

Definitions

• Housing component for a device to be ventilated
• the invention relates to a housing component for a device to be ventilated with a flat wall section and a perforated passage in the wall section, which has a plurality of openings and webs lying between the openings.
• housings In order to ensure adequate cooling of such devices, their housings generally have at least one perforated passage in a housing wall which has a plurality of openings and webs lying between the openings in order to allow air to flow through the housing. While optimal ventilation of the housing could be achieved through a completely open passage, grid-like ventilation openings are generally preferred because these ensure a certain mechanical protection of the devices located in the housing and, when using metal housings, an electromagnetic shielding of the electrical and electronic Ensure components.
• the openings in the ventilation passages are often in the form of slits, the openings should be smaller the higher the frequencies of the electromagnetic waves which are to be shielded by the housing.
• the invention is therefore based on the object of specifying a design for ventilation passages in housing walls of electrical or electronic devices which are to be ventilated for their cooling, which enables a maximum air flow and at the same time an adequate appropriate electromagnetic shielding of the device inside the housing guaranteed.
• Air flow through the perforated passage is always associated with a drop in pressure.
• the invention minimizes this pressure drop and thus maximizes the flow rates for the cooling of electrical and electronic devices by increasing the free area in relation to the total area of the perforated passage by using the third dimension for the perforated passage.
• the base area of the entire perforated passage always remains unchanged.
• the proportion of the free area to the base area can thus be increased, which leads to a reduced flow resistance.
• an essentially identical air flow and thus the same cooling effect can be achieved with a reduced fan speed, which results in both energy savings and less noise.
• an increased flow speed and thus a better cooling effect can also be achieved with the same fan speed.
• the net free area for the air flow is determined by the slots delimited by the webs, measured perpendicular to the effective surface of the webs, which results in an elongation of the webs by bending and thus an increase in the surface area and thus the free area.
• the housing of electrical and electronic devices also serves to shield electromagnetic fields.
• the housing is usually made of metal.
• the effective shielding is determined by the largest “open diameter” in the housing wall. Since the design of the perforated passage according to the invention does not change this largest open diameter, the invention has no negative influence on the electromagnetic shielding effect.
• the housing component according to the invention is preferably used in metal housings for electrical and electronic devices and in particular power supplies, computers and the like. It can be used in all cases in which electrical or electronic components are to be cooled by means of an air flow, the air flow being able to be generated by a fan or by free convection.
• the flow resistance is significantly reduced by the inventive design of the perforated passage.
• FIG. 1 and 2 are perspective views of two housings with a perforated passage according to the prior art and with a perforated passage according to the invention;
• Fig. 3 is a schematic plan view of a perforated passage according to the
• Fig. 4 is a schematic sectional view through the perforated passage of Fig.
• Figure 5 is a schematic sectional view through a perforated passage according to the invention.
• Fig. 6 is a diagram of the flow conditions in a fan-cooled device to explain the advantages of the invention.
• Fig. 1 shows schematically an example of a housing 10 for any electronic or electrical devices with a side wall 12, a rear wall 14 (front in the drawing) and a top wall 16.
• the housing 10 has a perforated passage 18 which is formed as a flat metal plate with alternating elongated slots 20 and webs 22.
• a schematic top view of such a perforated passage according to the prior art is shown in FIG. 3, with slots 20 and webs 22.
• the webs 22 are also referred to as metal bridges.
• the total area of the perforated area is delimited by a line 24.
• Fig. 4 which shows a schematic Schittdar position through the passage plate 18 of Fig. 3, the open air passage area, which is delimited by the webs 22, is schematically indicated by arrows 26.
• FIG. 2 shows a housing 30 for any electrical or electronic device with a side wall 32, a rear wall " 34 and a top wall 36 according to the invention.
• a perforated passage plate 38 for ventilating the interior of the housing.
• the passage plate 38 has slots 40 which are delimited by outwardly curved webs 42.
• Fig. 5 shows a schematic sectional view through the passage plate 38 with a curved web 42, arrows 46 schematically indicating the effective area of the passage openings delimited by the curved webs 42.
• the webs 42 can also be bent in the direction of the interior of the housing or alternately outwards and inwards. You can also be in a shape different from the shape shown, circular, angular, wavy or otherwise curved. It is essential in the inventive design of the passage plate 38 that the area of the passage openings 20 is increased in that the webs 42 delimiting the openings are at least partially offset from the plane of the wall section in which the passage opening is located. In particular, the webs 42 are lengthened by bending, so that the area of the passage openings 40 delimited by the webs increases. The following comparative measurements were carried out using the two housings shown in FIGS. 1 and 2:
• a standard perforation was selected with a perforated area of 75 mm x 34.5 mm, which is formed by a total of 16 slots and 15 webs with a length of 34.5 mm and a width of 3 mm.
• the width of the metal bars between the slots was 1.8 mm. This results in a share of the free area of the total area of 63%.
• the housing 30 according to the invention which is shown in FIG. 2, was provided with a passage plate 38, which has the following features:
• the base area of the perforated passage is, as in the embodiment of FIG. 1, 75 mm ⁇ 34.5 mm ,
• This Base area is provided with a total of 16 slots and 15 webs with an elongated length of 37 mm (in the selected example) and with a width of 3 mm.
• the width of the metal bars was also 1.8 mm. This results in a proportion of the free area to the total area of the passage opening of approximately 68%.
• a fan of the type NMB 3110 KL-04W-B60 (12V DC) was used, which has a maximum static pressure of 45 Pa or a maximum throughput of 1.25 m / min. can deliver.
• Ad 1 With the standard perforation according to FIG. 1, an air speed of 1.34 m / s was measured, which corresponds to an air flow rate of 0.5388 m 3 / min. At nominal power, a fan speed of 3.627 revolutions per minute was also measured.
• Ad 2 With the inventive design of the passage 38, which is shown in FIG. 2, on the other hand, an air speed of 1.44 m / s resulted, which corresponds to a flow rate of 0.57 m 3 / min.
• the fan speed measured at the same power was 3.570 revolutions per minute.
• This comparison measurement shows the flow resistance of the remaining system, including the pressure drop through the housing and the rear passage hole due to friction and the like.
• An overall view of the measurements results in an increase in the flow rate of approximately 6% if, instead of the flat standard perforation, the design of the perforated passage according to the invention is used in accordance with the specifications under 2. above.
• a more precise analysis of the flow or pressure conditions on the perforated surfaces with the aid of a flow simulation (CFD) shows that with the same pressure loss of 15 Pa there is an increase in throughput of approximately 12% or with the same throughput of 0.09 m 3 / s a pressure loss reduced by 26% if place the standard perforation, the perforation according to the exemplary embodiment of the invention shown is used. This factor can be further increased by an even greater bend and elongation of the webs 42 between the Durcl.
• Fig. 6 shows a graph of the flow curves in a cooled with a fan device, which has been modified in accordance with the 'above-described embodiments.
• the curve designated by the letter A in FIG. 6 represents the pressure (P) - flow rates (Q) - characteristic curve of the fan which was used in the exemplary embodiment described.
• This characteristic curve A determines the operating points of the system. If the fan is operated in a housing in which the rear has been removed, characteristic curve B applies; if the fan is operated in a housing which has a passage opening according to the invention, characteristic curve C applies; and if the fan is operated in a housing which has a passage with a standard perforation according to the prior art, characteristic curve D applies.
• characteristic curve D applies.

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• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Citations (3)

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• 2001
  • 2001-11-14 DE DE10155810A patent/DE10155810B4/de not_active Expired - Fee Related
• 2002
  • 2002-10-25 TW TW091125082A patent/TW563391B/zh active
  • 2002-11-07 US US10/495,380 patent/US20050052845A1/en not_active Abandoned
  • 2002-11-07 JP JP2003545088A patent/JP2005510069A/ja not_active Withdrawn
  • 2002-11-07 CN CN02822435.3A patent/CN1270589C/zh not_active Expired - Fee Related
  • 2002-11-07 WO PCT/EP2002/012439 patent/WO2003043395A1/de not_active Ceased
  • 2002-11-07 EP EP02779534A patent/EP1444875B1/de not_active Expired - Lifetime
• 2004
  • 2004-06-11 NO NO20042443A patent/NO20042443L/no unknown

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