EP2143313A1

EP2143313A1 - Method and arrangement for cooling equipment box

Info

Publication number: EP2143313A1
Application number: EP08750453A
Authority: EP
Inventors: Jukka Pekka Antero Ohtonen; Visa Panu Pellervo Viertola
Original assignee: Epec Oy
Current assignee: Ponsse Oyj
Priority date: 2007-04-23
Filing date: 2008-04-22
Publication date: 2010-01-13
Also published as: EP2143313A4; WO2008129134A1; FI121949B; FI20070318L; FI20070318A0

Abstract

The invention is related to a method and arrangement for cooling an equipment box (1). The equipment box comprises a bottom part (2) and a cover part (3) that are interconnected and will thus surround an equipment space (4) containing electric and/or electronic components. The heat generated by these components is conveyed to the structures of the equipment box, wherefrom it is transferred to the surroundings by an air flow provided between the bottom part and the cover part. This air flow is guided through at least one flow channel (8) to extend towards the upper surface (10) of the cover part (3) and the cooling elements (5) advantageously provided thereon.

Description

METHOD AND ARRANGEMENT FOR COOLING EQUIPMENT BOX

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a method in accordance with the preamble of claim 1 for cooling an equipment box.

[0002] The invention also relates to an arrangement in accordance with the preamble of claim 9 for cooling said equipment box.

[0003] The present invention is particularly applicable for cooling equipment casing that protects electronic parts, whereby it may be used in demanding conditions for cooling powerful computers or equipment having similar cooling needs. Otherwise a temperature rise in the equipment box, caused by high energy consumption of electronic components, will cause overheating of components and reliability problems with the equipment.

[0004] It is previously known to cool electronic components using passive cooling technique, for instance. In that case components generating a lot of heat are connected through the best possible thermal contact to the equipment box surrounding them. The thermal energy conducted to the structures of the equipment box in this manner is arranged to get transferred from the structures to the surroundings through free convection and heat radiation.

[0005] The use of the passive cooling technique is not possible in all cases, however, because a cooling surface having a sufficiently large heat transfer capacity is not always possible to provide without unreasonable difficulties.

[0006] On the other hand, there are also known so-called active techniques, in which cooling air is circulated through an equipment box surrounding electronic components and at the same time the cooling air flow is to be conveyed as efficiently as possible towards the components that generate a lot of heat.

[0007] Openings required by the cooling air circulating through the equipment box prevent, however, implementation of a waterproof structure, which limits the use of the equipment in demanding conditions. Impurities in air circulating through the electronic components may also cause corrosion and lead to component damage. When air filters are used in a solution of this kind, they require regular servicing in order to maintain sufficient cooling power. Moreover, as cooling is designed it should be taken into account that filters reduce the air flow to some extent even when they are clean. BRIEF DESCRIPTION OF THE INVENTION

[0008] The object of the invention is thus to provide a method and an arrangement implementing the method such that the above problems may be solved. This object is achieved such that the method and the arrangement for cooling an equipment box comprises the characteristics defined in the claims in accordance with the invention.

[0009] To put it more precisely, the method of the invention is mainly characterized by what is stated in the characterizing part of claim 1. On the other hand, the arrangement of the invention is mainly characterized by what is stated in the characterizing part of claim 9.

[0010] Preferred embodiments of the invention are disclosed in the dependent claims.

[0011] The invention is based on the idea that thermal energy from the power losses of the electronic components is transferred to the structures of the equipment box by conduction and convection, and possibly by circulating clean indoor air inside the equipment box. The thermal energy transferred in this manner in the structures of the equipment box is transferred to the surroundings by generating an air flow outside the equipment that is conveyed by means of the equipment box design and surfaces that come into contact with the ambient air to external cooling elements integrated with the equipment box structures.

[0012] Considerable advantages will be achieved with the invention. So, the present invention and the arrangement implementing it solve the problem, how cooling of equipment including electronic components may be implemented effectively in applications, where requirements for tightness of the equipment box does not allow use of air flowing through the equipment box, which enables water- and dustproof implementation.

[0013] The invention also provides better cooling power than the passive techniques, which cooling power is necessary in applications where high computing power is required. Efficient cooling with easy serviceability contributes to maintain the electronic components housed in the equipment box longer in working order.

[0014] The present arrangement provides solution for the implementation of cooling in serial production by reducing substantially the manual work steps required in the construction of cooling. The thermal energy conveyed to the structures of the equipment box is transferred to the surroundings with an air flow that circulates around the device only along the outer surfaces thereof. The device is provided with one or more flow channels that are designed to guide the air flow towards the outer surface of the equipment box and the cooling elements provided thereon, which increases the cooling power substantially. Being arranged on the outer surface of the equipment box it is easy to design the size, shape and number of the cooling elements to conform to the necessary cooling power in the best possible manner.

[0015] An important advantage of the present arrangement is also that cleanliness of cooling ribs can be readily found out visually by checking the exterior of the equipment box. Hence, a condition that considerably affects the cooling power may be found out without having to detach or remove parts especially for this purpose. Correspondingly, cooling elements, such as cooling ribs or other members on the outer surface of the equipment box, are easy to clean without opening the equipment box.

[0016] As the flow channels and the cooling ribs are integral parts of the equipment box, they are advantageously produced in the moulding process used for manufacturing moulded pieces for the equipment box. Thus, there will be no need to machine or assemble flow channels or cooling ribs mechanically. This improves the cost efficiency of the solution and the uniform quality of end results when devices are manufactured in serial production.

[0017] The flow channels integrated in the equipment box structure enable orientation of the external cooling air flow accurately to the surface and cooling ribs of the equipment box, which transfers the thermal energy conveyed from the equipment space to the equipment box structures efficiently to the surroundings in comparison with the passive cooling.

[0018] In order to create air flow required in cooling it is possible to use components integrated in the equipment box or an external blower or some other means producing air flow, such as ventilation or air conditioning apparatus of a vehicle or a building.

[0019] The attachment and orientation of the components used for creating the air flow enable an equipment box structure that is lower than in the known solutions. Particularly radial blowers are suitable for application in the structure of the invention. Because various blowers can be arranged on the outer surface of the equipment box, they are readily exchangeable without opening the equipment box, whereby the interior of the equipment box need not be subjected to surroundingsal impurities and, for instance, humidity during maintenance work. The importance of this becomes particularly apparent in demanding surroundingsal conditions. The service life of the blower is limited at any rate and therefore it is advantageous to plan this maintenance operation to be as simple as possible to perform.

[0020] As the blowers are arranged on the outer surface of the equipment box, requirements set for their physical dimensions are not so high as in the case where they had to be arranged in the equipment space. The blowers arranged on the outer surface of the equipment box may even be selected to have a diameter that is larger than the height of the equipment space in order to ensure sufficient air flow to the cooling elements.

[0021] In accordance with the present invention, irrespective of the compact structure of the equipment box it is possible to mount more than one blower, or other means producing air flow, on the equipment box, whereby the fault resistance of the assembly will be further improved, because the arrangement may continue to function normally despite a fault in one component.

[0022] Thanks to the closed equipment box structure that is enabled by the invention, pre-heating of the apparatus required in cold use conditions will take place faster than in an equipment box comprising cooling apertures. This is of importance particularly in demanding vehicle and work machine applications, such as forestry equipment, rock drill rigs and other mobile work machines. These machines often operate in extremely cold conditions, and therefore long pre-heating may be necessary, before it is possible to start a computer mounted therein.

[0023] The invention may be applied to casing and cooling of electronic components in all applications where good waterproofness and dust- proofness as well as high heat transfer capacity are required of the equipment casing.

[0024] Other advantages achieved by the invention are described below in connection with a detailed description of particular embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the following, some preferred embodiments of the invention will be described in greater detail, with reference to the attached drawing, in which Figure 1 is an axonometric top projection of an embodiment of the arrangement in accordance with the present invention,

Figure 2 is an axonometric bottom projection of the arrangement of

Figure 1 ,

Figure 3 is a side projection of the arrangement of Figure 1 , Figure 4 is a front end projection of the arrangement of Figure 1 , Figure 5 is a rear end projection of the arrangement of Figure 1 , Figure 6 is a partial longitudinal section of the arrangement of Figure

1,

Figure 7 is an axonometric top view of the arrangement of Figure 1 when a cover part is removed, and

Figure 8 is an axonometric bottom projection of an alternative embodiment of the arrangement in accordance with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0026] Some preferred embodiments of the present method and arrangement for cooling an equipment box have been described in the following with reference to the above-mentioned figures. In this case the method has been described with the assistance of said arrangement that comprises structural parts provided in the figures with reference numerals corresponding to reference numerals used in the present description.

[0027] Figure 1 shows an embodiment for an arrangement to cool an equipment box. In this case the equipment box 1 comprises a bottom part 2 and a cover part 3 that are interconnected and surround an equipment space 4 receiving electric and/or electronic components. The equipment space is advantageously isolated in a waterproof and dustproof manner from its surroundings in order that the device or devices housed therein may be used in highly difficult conditions.

[0028] As it can be seen from the figure, the cover part 3 of the present embodiment is provided with a number of cooling elements 5 projecting therefrom. These cooling elements extend substantially between two opposing outer edges 6 and 7 of the equipment box 1 such that one end thereof is in the vicinity of at least one flow channel 8 that is separate from the equipment space 4 and integrated in the outer edge of the equipment box.

[0029] A flow channel 8 of this kind, for instance as shown in Figures 6 and 7, comprises a tubular element that is open at opposite ends, sub- stantially C-shaped in cross section and extending from the bottom part 2 to the cover part 3. In the bottom part of the equipment box the flow channel advantageously joins with a mounting recess 9 provided in the bottom part. It is also possible to arrange the cross section of the flow channel to reduce while approaching either the cover part or the bottom part of the equipment box so as to control the air flow rate provided in the flow channel.

[0030] Because the equipment box 1 is principally manufactured using a conventional moulding process, finished equipment box parts and flow channel 8 parts required by cooling are advantageously produced in the same manufacturing process. Thus the mechanical cooling structures need not be separately machined or assembled mechanically.

[0031] In the flow channel 8 there is provided an air flow that is arranged to extend to the upper surface 10 of the cover part 3 and to the cooling elements advantageously provided therein. The air flow thus runs from the bottom part 2 towards the cover part, and the flow channel is designed such that it guides the air flow towards the outer surface of the equipment box and the cooling elements 5 advantageously therein and produces high air pressure and flow rate. For this purpose, at least one means 11 , for instance a radial blower, is arranged in the mounting recess 9 of the bottom part in order to generate air flow in the flow channel 8. Naturally, the radial blower may be substituted, for instance, by an axial blower or the like means. In the mounting recess the means arranged in the bottom part are also protected against mechanical shocks. Orientation and attachment of the means also enable an overall solution that is lower in height than conventional ones.

[0032] It is possible, of course, to provide air flow in the flow channel 8 also by connecting in the mounting recess 9 at least one device outside the arrangement. This device may be, for instance, an air conditioner of a work machine.

[0033] On the other hand, it is also possible to consider that air flow passes from the cover part 3 towards the bottom part 2. In that case the flow channel 8 provides an air flow on the outer surface of the equipment box 1 and on the cooling elements 5 advantageously thereon. For this purpose, in the mounting recess of the bottom part there is arranged at least one means 11 , for instance a centrifugal exhaust fan, for generating an air flow in the flow channel. It is also possible to provide air flow in the flow channel also by creat- ing a partial vacuum in the mounting recess by means of an external device connected thereto.

[0034] The capacity of the arrangement to remove straining thermal load from the equipment space 4 can be advantageously controlled by affecting the shape and positioning of the cooling elements 5 on the upper surface 10 of the cover part 3. Thus, in accordance with Figure 1 , the cooling elements are advantageously arranged to approach one another as they go further away from the flow channel.

[0035] The present arrangement for cooling the equipment box 1 will be used as follows. Heat constituting the thermal load from power losses of electronic components arranged in an equipment space 4 is transferred to the structures of the equipment box 1 by conduction. Heat transfer may also be enhanced by convection, whereby the equipment space comprises members particularly for circulating clean indoor air inside the equipment space. The heat transferred into the structures of the equipment box is further transferred to the surroundings by generating an air flow from outside the arrangement that is guided by means of the mechanical structures of the equipment box towards the equipment box and advantageously towards the cooling elements integrated with the equipment box and projecting from the outer surface thereof. In the embodiment of the figures the cooling elements thus comprise rib-like members projecting from the surface of the equipment box.

[0036] As the cooling elements 5 are mainly arranged in the cover part 3 of the equipment box 1 , it is possible to provide an air flow in the equipment box between the bottom part 2 and the cover part, which air flow is conveyed along at least one flow channel 8 to extend towards the upper surface 10 of the cover part and the cooling elements projecting therefrom. The flow channels are designed such that the generated air pressure and flow rate are high and the flow is directed towards the surface of the equipment box and the cooling elements.

[0037] The heat conducted to the structures of the equipment box 1 and the cooling elements 5 is thus transferred to the surroundings of the arrangement by air flow that circulates only along the outer surfaces of the equipment box. The flow channels 8 are designed such that they guide the air flow towards the surface of the equipment box and the cooling elements, which increases the cooling power substantially. [0038] The air flow may be directed both from the bottom part 2 to the cover part 3 by guiding it to the flow channel 8 extending from the bottom part to the cover part and from the cover part to the bottom part by creating a partial vacuum in the flow channel extending from the bottom part to the cover part. This air flow is provided by creating a local pressure difference in the mounting recess locating in the bottom part of the equipment box and communicating with the flow channel, which pressure difference may be created with a blower or an exhaust fan mounted in the mounting recess or by directing an external air jet or an external suction to the mounting recess.

[0039] The present arrangement may be applied to casing and cooling of electronic equipment in all applications, where good waterproofness and dustproofness and high heat transfer capacity are required of the equipment casing.

[0040] It is apparent to a person skilled in the art that as technology advances the basic idea of the above-described solution may be implemented in a variety of ways. The presented solution and the embodiments thereof are thus not restricted to the above examples, but they may vary within the scope of the claims.

Claims

1. A method for cooling an equipment box (1), which equipment box comprises a bottom part (2) and a cover part (3) that are interconnected and surround an equipment space (4), whereby heat generated in the equipment space is conducted to the structures of the equipment box and cooling elements (5) therein, characterized in that an external air flow is guided to the upper surface (10) of the equipment box, which air flow is guided by means of at least one flow channel (8) provided in the equipment box to extend towards the upper surface (10) of the cover part (2), on which upper surface the air flow flushes the cooling elements (5) projecting from the equipment box, for removing heat from the structures of the equipment box.

2. The method of claim 1, characterized in that the air flow is provided by creating a local pressure difference in a mounting recess (9) outside an equipment space (4) and locating in the bottom part (2) of the equipment box (1) and communicating with the flow channel (8) connecting the bottom part to the cover part (3).

3. The method of claim 1 or 2, characterized in that the air flow is directed from the bottom part (2) to the cover part (3) by guiding it to the flow channel (8).

4. The method of claim 1 or 2, characterized in that the air flow is directed from the cover part (3) to the bottom part (2) by creating a partial vacuum at the end of the flow channel (8) on the side of the bottom part.

5. The method of claim 4, characterized in that an external air jet is directed to the mounting recess (9).

6. The method of claim 4, characterized in that an external suction is directed to the mounting recess (9).

7. The method of any one of the preceding claims, characterized in that heat generated in the equipment space (4) is conducted to the cooling elements (5) projecting from the outer surface of the equipment box (1), whereby the airflow is directed particularly to said cooling elements.

8. The method of any one of the preceding claims, characterized in that heat transfer to the structures of the equipment box (1) is enhanced by circulating air in the equipment space.

9. An arrangement for cooling an equipment box (1), which equipment box comprises a bottom part (2) and a cover part (3) that are interconnected and surround an equipment space (4), which equipment box comprises cooling elements (5) for transferring heat from the equipment space, characterized in that at least one flow channel (8) separate from the equipment space extends from the bottom part (2) to the cover part (3) and that the upper surface (10) of the cover part (3) comprises cooling elements (5) projecting from the equipment box, whereby the air flow provided in the flow channel is arranged to extend to the cooling elements on the upper surface of the cover part.

10. The arrangement of claim 9, characterized in that the upper surface (10) of the cover part (3) comprises cooling elements (5) that draw away from the flow channel (8) and project from the upper surface.

11. The arrangement of claim 9 or 10, characterized in that the bottom part (2) of the equipment box (1) comprises a mounting recess (9) in connection with the flow channel (8) for providing a local pressure difference to be created in the flow channel of the mounting recess (9).

12. The arrangement of claim 9, 10 or 11, characterized in that in the bottom part (2) there is arranged at least one means (11) for generating an air flow in the flow channel (8).

13. The arrangement of claim 9, 10 or 11, characterized in that in the flow channel (8) there is connected at least one device from outside the arrangement for generating an air flow.

14. The arrangement of claim 13, characterized in that the device comprises an air conditioner of a work machine for providing an air flow directed from the bottom part (2) to the cover part (3).

15. The arrangement of any one of claims 10 to 14, characterize d in that the cooling elements (5) are arranged to approach one another as they go further away from the flow channel (8).

16. The arrangement of any one of claims 8 to 15, characterized in that the flow channel (8) is arranged on the outer edge of the equip- merit box (1) such that it forms an element having a substantially C-shaped cross section and extending from the bottom part (2) to the cover part (3).

17. The arrangement of claim 16, characterized in that the cross section of the flow channel (8) is arranged to reduce when approaching the cover part (3) of the equipment box (1).

18. The arrangement of claim 16, characterized in that the cross section of the flow channel (8) is arranged to reduce when approaching the bottom part (2) of the equipment box (1).