GB2314920A

GB2314920A - A watertight casing and heat dissipation device

Info

Publication number: GB2314920A
Application number: GB9713341A
Authority: GB
Inventors: Kazuo Komatsu
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 1996-06-24
Filing date: 1997-06-24
Publication date: 1998-01-14
Anticipated expiration: 2017-06-24
Also published as: CN1121133C; GB9713341D0; GB2314920B; HK1005538A1; JPH1013072A; JP2861945B2; SG54520A1; ID17159A; CN1171530A

Abstract

In a closed type device composed of upper and lower casings 11, 12, a plurality of through holes 14 having a predetermined size d are formed at predetermined intervals in the upper and lower casings, the through holes serving to release heat from the interior of the device. A thin sheet 13 having water repellent property and air permeability and having a plurality of fine holes is adhesively attached to the inner surfaces of the upper and lower casings so as to cover all of the through holes.

Description

A WATERTIGHT CASING AND HEAT DISSIPATION DEVICE The present invention relates to a watertight casing and a heat dissipation device, in particular to a heat radiation structure for a closed type device, in particular for such a device for use in the open air.

As a heat radiation structure for a closed type device for use in the open air, a cooler structure of the heat pipe type has been adopted, in which heat pipes having heat collecting fins are provided in a casing of the heat radiation structure and heat pipes having heat radiation fins are provided outside the casing of the structure. For example, in Japanese Patent Publication No. 5943115, a cabinet for an electronic device, which keeps temperatures in the device approximateiy constant using a heat pipe, is disclosed. Fig. 1A is a front view of the heat radiation structure, Fig. 1B is a section view taken along the line Ill-Ill of Fig. IA, and Fig. 1C is a section view taken along the line ll-ll of Fig. 1A. In this prior art, three heat pipes 5, each operating at different temperatures, are provided in the upper zone of a casing 1. Heat collecting fins 4 are mounted to the portions of the heat pipes 5 located inside the casing 1 and heat radiation fins 4a are mounted to the portions thereof located outside the casing 1. The heat pipes 5 are integrally assembled beforehand to the heat collecting fins 4, heat radiation fins 4a, heat insulating material la and mounting plate 7 to constitute a heat pipe assembly body. The assembly body is fixed to the casing 1 in the following manner.

The assembly body is inserted into the casing 1 through a hole formed in the upper part of the assembly body so as to correspond to the shape of the heat insulating material la, and the mounting plate 7 is fixed to the casing 1 by means of screw. Then, a gap around the hole is filled with suitable resin to fix the assembly body to the casing 1. Further, a sunshade 6 is provided outside the assembly body. Such heat radiation structure of the closed cabinet type far radio equipment has been used.

In the prior art as described above, since the heat pipe is disposed across the casing, there is a problem that a relatively large space is required to mount the assembly body and hence the size of the closed type device becomes larger. Furthermore, since expensive heat pipe coolers are used and many constituent parts are used, construction man-hours increase, resulting in increased cost.

An object of at least the preferred embodiment of the present invention is to provide a heat radiation structure of a device for use in the open air at low cost, without using heat pipe coolers, in which no mounting space is required and the size of device can be reduced, and heating structures can be easily manufactured and the number of parts can be reduced.

Accordingly, in a first aspect the present invention provides a watertight casing adapted to dissipate heat from within, comprising at least one aperture closed by a membrane which is permeable to air but impermeable to water droplets.

In a second aspect, the present invention provides a heat dissipation device comprising an upper casing, a lower casing, a plurality of through holes being formed in said upper and lower casings, and sheet material covering the holes and having a plurality of holes formed therein to prevent water droplets from entering said device whilst permitting the passage of air.

A preferred embodiment of the present invention provides a heat radiation structure for a closed device in which upper and lower casings are combined to provide watertightness and in which a plurality of through holes are formed in the upper and lower casings and a sheet having therein many fine holes is mounted to the upper and lower casings, respectively, so as to cover all of the through holes.

A plurality of through holes having a predetermined size may be formed in the upper and lower casings at predetermined intervals and a sheet may be formed of a network having a large number of meshes.

Preferred features of the present invention will now be described, purely by way of example only, with reference to the accompanying drawings, in which:- FIG. lA is a front section view of a conventional heat radiation structure; FIG. lB is a section view taken along the line Ill-Ill of FIG. lA; FIG. lC is a section view taken along the line II-II of FIG. lA; FIG. 2A is a plan view showing an embodiment of a heat radiation structure FIG. 2B is a side view of the embodiment of the heat radiation structure FIG. 2C is a partial section view taken along the line A-A of FIG. 2A; and FIG. 3 is a partial plan view showing a sheet of the heat radiation structure FIGS. 2A, 2B and 2C show a heat radiation structure of a closed type device of the present invention. FIG. 2A is a plan view, and FIG. 2B is a side view. FIG. 2C and FIG. 2B are a partial section view, and FIG. 3 shows a sheet in detail.

As shown in FIGS. 2A and 2B, the heat radiation structure of the present invention consists of an upper casing 11, a lower casing 12 and a sheet 13 for heat radiation. The foregoing upper casing 11 is provided with a plurality of through holes 14 having a predetermined size d at predetermined intervals, to dissipate the heat inside the heat radiation structure.

As shown in FIG. 2C, the lower casing 12 has the same structure and a plurality of through holes 14 are formed therein. The foregoing sheet 13 is formed of a thin material having water resistance property and air permeability. As shown in FIG. 3, the sheet 13 is provided with a plurality of fine holes 13a and has a structure such that heat inside the casings is allowed to radiate through the holes 13a, but water and dusts coming from the outside are prevented from getting into the casings. Sizes of the fine holes should preferably be 1 to 10 microns, and the fine holes serve to prevent the invasion of water drops but allow vapor to freely pass therethrough, where, sizes of water drops, that is rain, are generally about 2000 microns and sizes of vapor are about 0.001 microns. An adhesive tape 13b, having a width w, is adhered to the periphery of the sheet 13 to attach the sheet 13 integrally to the inner surfaces of the casings 11 and 12 so as not to cover the holes 14. To attach the sheet 13 to the upper casing 11, the sheet 13 is attached to the inside surface of the upper casing 11 using the adhesive tape 13b so that all the holes 14 are covered with the sheet 13. In the case of the lower casing 12, the same process as described above can be taken. By combining the upper casing 11 with the lower casing 12, a closed type device can be obtained, so that invasion of water and dusts can be prevented and heat in the device can be freely released to the outside.

As described above, since the plurality of through holes are provided in the top and bottom plates of the upper and lower- casings, heat generated in the device can be radiated to the outside. In addition, since the sheet 13 having the plurality of fine through holes 13b is attached to the inside surface of the upper and lower casings 11 and 12 so as to cover all of the through holes 14, watertightness required for an outdoor device can be obtained and invasion of dusts can be prevented. Since the sheet has air permeability, heat radiation effect within the casings can be maintained.

The through holes are formed in the upper and lower casings and the sheet having a plurality of fine holes is adhesively attached to the inside surfaces thereof, and hence heat radiation effect can be obtained without using heat pipes. Therefore, an inexpensive heat radiation structure -able to achieve miniaturization and simplicity of the device as well as reduction of the number of parts can be provided, and the structure can be easily assembled.

Although the preferred embodiment of the present invention has been described in detail, it should be understood that various changes, substitutions and alteration can be made therein without departing from the scope of the invention as defined by the appended claims.

Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.

The text of the abstract filed herewith is repeated here as part of the specification.

Claims

1. A watertight casing adapted to dissipate heat from within, comprising at least one aperture closed by a membrane which is permeable to air but impermeable to water droplets.

2. A casing according to Claim 1, comprising upper and lower casings and a plurality of said apertures formed in said upper and lower casings to permit air to pass through the casing.

3. A casing according to Claim 1 or 2, wherein said membrane comprises at least one mesh.

4. A heat dissipation device comprising an upper casing1 a lower casing, a plurality of through holes being formed in said upper and lower casings, and sheet material covering the holes and having a plurality of holes formed therein to prevent water droplets from entering said device whilst permitting the passage of air.

5. A heat dissipation device according to Claim 4, wherein said through holes are formed at predetermined intervals.

6. A heat dissipation device according to Claims 4 or 5, wherein said sheet is formed from a network body comprising a large number of fine meshes.

7. A watertight casing or heat dissipation device substantially as herein described with reference to and as shown in Figures 2 and 3 of the accompanying drawings.