Abstract:
An adaptor is provided for use with the heat sink, said heat sink comprising a base for contacting a heat source and a plurality of protrusions extending from said base. The adaptor itself comprises a base and a structure projecting therefrom. The structure is arranged to mate with one or more protrusions on the heat sink to enable heat transfer by conduction from the heat sink to the adaptor.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of British Patent Application No. GB  1112598 . 6  filed on Jul. 21, 2011, the entire disclosure of which is incorporated herein by reference. 
       FIELD 
       [0002]    The invention relates to an adaptor for a heat sink. 
       BACKGROUND 
       [0003]    Heat sinks are well known devices that are used in a range of industries for cooling other devices that generate high temperatures. The term “heat sink” is generally used to describe any component or apparatus that transfers heat generated within a solid device to a fluid such as a liquid or air by convection. Heat sinks are used in refrigeration and air conditioning systems as well as for cooling a range of electronic and opto-electronic devices including computer central processing units (CPU&#39;s) and other processors. 
         [0004]      FIG. 1  shows a typical heat sink  100 . It comprises a base  102  and a series of fins  104  projecting outwardly therefrom. In the heat sink  100  shown in  FIG. 1 , the fins  104  project substantially perpendicularly from an upper face of the base  102 . Each fin  104  is relatively thin so that a plurality of fins  104  can be arranged on the upper face of the base  102  with a gap between adjacent fins  104 . Each fin  104  comprises first and second large substantially flat faces opposite one another. In  FIG. 1  the large faces are substantially rectangular. 
         [0005]    Other configurations of heat sink that differ from the one shown in  FIG. 1  are well known. For example the fins in a heat sink may not project substantially perpendicularly from the base. They may instead project at different angles to create a flared or fanned fin arrangement. Alternatively or additionally, a plurality of pins may be used to replace the essentially planar fins shown in  FIG. 1 . In general, the purpose of the fins or pins in a heat sink is to create as large a surface area as possible within a given volume. That surface area is used for heat transfer from the heat sink to a surrounding fluid. 
         [0006]    In operation, the base of a heat sink is placed in contact with a device that acts as a heat source and generates high temperatures, from which heat is to be directed away. The base can be placed in direct physical contact with the heat source. Optionally, a thermal adhesive or thermal grease may be added to the base of the heat sink to improve its thermal performance. Heat is conducted away from the heat source into the base and through the fins of the heat sink. That heat can then travel by convection from the heat sink to the surrounding fluid. The increased surface area of the fins aids transfer of heat to the surrounding fluid. Furthermore, the heat transfer by convection to the surrounding fluid can be enhanced by flow of the fluid around the heat sink, in particular in the gaps between the fins of the heat sink. Fluid can be forced between the fins of a heat sink, for example using a fan. 
         [0007]    Whilst existing heat sinks are widely utilised and can be very useful in cooling heat generating devices, they are nonetheless limited to cooling by thermal convection. They are unable to operate in any other cooling mode without significant changes being made to their fundamental design. Cooling systems which include a heat sink are difficult to configure for use in different modes of operation without replacement of the heat sink. Therefore the range of suitable applications for conventional heat sinks is limited. 
         [0008]    For example, conventional heat sinks are unsuitable for use in environments where the air used to provide ‘forced air cooling’ contain particulates (wood, stone, fibres etc.), as such particulates are likely to clog the fan circulating the air and the fins of the heat sink over time, reducing the efficiency of the heat sink. They also conventionally are unsuitable for use in environments where a high degree of protection is required from water, gas or dust as this necessitates installation of the heat sink in a sealed enclosure, limiting the supply of cool air to supply to the heat sink and thus reducing its efficiency. 
       SUMMARY 
       [0009]    According to an aspect there is provided an adaptor for use with a heat sink, said heat sink comprising a base for contacting a heat source and a plurality of protrusions extending from said base. The adaptor itself comprises a base and a structure projecting from that base wherein the structure is arranged to mate with one or more protrusions on a heat sink to enable heat transfer by conduction from the heat sink to the adaptor. Preferably at least one surface of the structure on the adaptor can come into direct contact with a surface of a protrusion on the heat sink in order to enable the heat transfer by conduction from the heat sink to the adaptor. The structure may comprise projections, fins or pins extending from the base of the adaptor. Alternatively the structure may be substantially solid with recesses or channels therein into which protrusions on a heat sink can insert. The adaptor can channel heat which it collects from a heat sink to another location or cooling system by a range of different heat transfer means. 
         [0010]    According to an aspect there is provided a cooling system for a heat source. The cooling system includes a heat sink comprising a base for contacting the heat source and channelling heat away therefrom as well as a plurality of protrusions extending from said base of the heat sink. The cooling system further comprises an adaptor comprising a base and a structure projecting from the base wherein the structure on the adaptor is arranged to mate with one or more of the protrusions on the heat sink to enable heat transfer by conduction from the heat sink to the adaptor. 
         [0011]    According to another aspect there is provided a method of adapting a heat sink, said heat sink comprising a base for contacting a heat source and a plurality of protrusions extending from that base. The method comprises fitting an adaptor to the heat sink wherein that adaptor comprises a base and a structure projecting from said base. When the adaptor is fitted to the heat sink the structure on the adaptor is mated with one or more of the protrusions on the heat sink to enable heat transfer by conduction from the heat sink to the adaptor. Heat can then be channelled away from the adaptor using any suitable heat transfer technique. 
         [0012]    According to another aspect there is provided a method of transferring heat away from a heat source. The method comprises putting a heat sink in contact with the heat source, said heat sink comprising a base for contacting the heat source and a plurality of protrusions extending from said base. The method further comprises fitting an adaptor to the heat sink wherein the adaptor comprises a base and a structure projecting from said base wherein fitting the adaptor to the heat sink includes mating the structure on the adaptor with one or more of the protrusions on the heat sink to enable heat transfer by conduction from the heat sink to the adaptor. Optionally the method may also comprise bringing the base of the adaptor, which is distal to the heat source when the heat sink is in contact therewith, into connection with an external component. That external component may be a cooling device. 
     
    
     
       FIGURES 
         [0013]    Embodiments and examples will now be described with respect to the appended figures of which: 
           [0014]      FIG. 1  shows an example of an existing finned heat sink; 
           [0015]      FIG. 2  shows an example of a heat sink adaptor for use in conjunction with the heat sink of  FIG. 1 ; 
           [0016]      FIG. 3  shows the adaptor of  FIG. 2  in connection with a heat sink; and 
           [0017]      FIG. 4  shows a plan view of the adaptor of  FIG. 2  in connection with a heat sink. 
       
    
    
     OVERVIEW 
       [0018]    In overview there is provided an adaptor for use with a heat sink. In particular the adaptor can be used with a finned heat sink. The adaptor mates with the heat sink to enable heat transfer by conduction from the heat sink into the adaptor. Preferably at least one surface of the adaptor should directly contact a surface of the heat sink to enable such conduction. Increasing the size of the surface area over which the adaptor directly contacts the heat sink increases the extent of heat transfer therebetween. The adaptor has a structure which can include fins or other projections that insert into the gaps between protrusions such as fins on a heat sink so that heat can travel from those protrusions into the adaptor. 
         [0019]    The physical configuration of the adaptor is largely dictated by the physical size and shape of the heat sink with which it is to be used. The adaptor must be able to mate with the heat sink and preferably it should be possible to lock the adaptor and heat sink together. At its distal end, away from the heat source which contacts the heat sink, the adaptor has a base. Preferably the outermost face of the base is substantially flat. Such an arrangement enables the adaptor to be connected to other external components such as other cooling devices. The adaptor may also comprise built-in cooling or heat transfer components such as liquid filled pipes. 
       DETAILED DESCRIPTION 
       [0020]    The heat sink adaptor disclosed herein can be better understood with respect to the figures. As discussed above in the background section,  FIG. 1  shows a typical existing finned heat sink  100 .  FIG. 2  shows such a heat sink aligned with an adaptor  200  for use therewith. 
         [0021]    The adaptor  200  shown in  FIG. 2  comprises a base  202  and a series of fins or other projections  204  extending therefrom. In the adaptor shown in  FIG. 2  the projections  204  extend substantially perpendicularly from a face of the base  202 . Each projection  204  is substantially rectangular in cross section and is relatively thin, with two large faces opposite one another, similar to the fins  104  described above with respect to the known heat sink  100 . Because the adaptor  200  shown in  FIG. 2  is for use with an existing finned heat sink such as the one shown in  FIG. 1 , the thickness of the projections  204  therein should ideally be sized to fit into the gaps between adjacent fins  104  in the heat sink  100 . This can further be understood from  FIGS. 3 and 4  which show the adaptor  200  in connection with the heat sink  100 . 
         [0022]    The adaptor  200  can include enough projections  204 , appropriately sized and spaced, as to fit into every other gap between fins  104  in the heat sink  100 , as shown in  FIGS. 2 to 4 . This ‘every other’ fin arrangement between the heat sink  100  and the adaptor  200  allows for the fins  104  of the heat sink  100  to move slightly as they receive the approaching projection  204  from the adaptor. Alternatively the adaptor  200  could have enough projections  204  as to fit into every gap between fins  104  in the heat sink  100  or only to fit into some of the gaps. 
         [0023]    The projections  204  in one embodiment provide a friction fit between the adaptor  200  and a heat sink  100  to ensure good surface area contact. Any suitable configuration of the projections  204  could be implemented, provided sufficient surface area contact is ensured between the heat sink  100  and the adaptor  200  to allow the adaptor  200  to conduct enough heat from the heat sink  100  for a given situation. 
         [0024]    The adaptor  200  can be aligned with the fins of a heat sink  100  as shown in  FIG. 2  and inserted into the heat sink  100  as shown in  FIGS. 3 and 4  to form a mating connection. The heat sink  100  and adaptor  200  combine to form a cooling system. 
         [0025]    According to an embodiment, when the adaptor  200  is mated with the heat sink it will not occupy all of the gaps between the fins of the heat sink, so that there will still be some space for air or other fluid to flow through the cooling system. This allows the cooling system to cool at least partially using convection and so not rely entirely on conduction of heat from the heat sink  100  to the adaptor  200  in order to direct heat away from the heat sink  100 . 
         [0026]    The faces of the projections  204  on the adaptor  200  should fit as closely as possible to the respective fins  104  of the heat sink, via which heat is conducted out of the heat sink into the adaptor  200 . The shape and orientation of the projections  204  on the adaptor  200  should also be matched as closely as possible with the shape and orientation of the fins  104  of the heat sink so that the adaptor  200  and heat sink can fit together easily and so that a large common surface area is provided for conduction of heat from the fins  104  of the heat sink to the projections  204  of the adaptor  200 . 
         [0027]    The adaptor  200  should be designed to provide as large a contact surface as possible for the heat sink with which it is to be used, to maximise heat transfer by conduction from the heat sink to the adaptor  200 . For example, as shown in  FIG. 4 , the adaptor  200  shown in  FIGS. 2 and 3  provides three contact surfaces for each fin  104  of the heat sink, via which heat can travel by conduction into the adaptor  200  out of the heat sink. 
         [0028]    As shown in  FIG. 3 , the adaptor  200  can be fixed to the heat sink  100  by any suitable means such as bolts  206 . The method of attachment should preferably be temporary, i.e. reversible, rather than permanent so that the adaptor  200  can be fitted to an existing heat sink when appropriate for certain applications and removed therefrom at other times without requiring any significant adaptation of either device. According to an embodiment, screws are used for fixing the adaptor  200  to the heat sink wherein the thread of the screw can form a thread in the walls of the fins of the heat sink during insertion. 
         [0029]    In addition to the projections  204  described above, the adaptor  200  as shown in  FIGS. 2 to 4  comprises a base  202 . Each of the projections  204  terminates at the base  202  therefore the majority of the heat which is conducted into the adaptor  200  from the heat sink will be directed towards the base  202 . As shown in  FIG. 4 , ideally the base  202  should have a substantially flat outer face, opposite the face from which the projections  204  extend. That substantially flat face can act as a flat surface for contact between the adaptor  200  and an external component such as a cooling device. Or another type of physical connection can be made between the adaptor  200  and the cooling device. For example that cooling device could be a water cooled heat sink, an air cooled plate or a “cold plate” cooling device. As is known in the art, such cooling devices cannot be used in direct contact with a conventional heat sink such as the one shown in  FIG. 1  which transfers heat by convention to fluid only. However if an adaptor  200  such as the one shown in  FIGS. 2 to 4  is used in conjunction with a conventional heat sink, intermediate the heat sink and the cooling device, those cooling devices (and other components) can be successfully used in conjunction with the conventional heat sink without having to permanently alter the design of either the heat sink or the cooling device itself. Therefore the adaptor increases the usefulness of the heat sink and the range of applications for which it can be used. 
         [0030]    As well as being able to connect to external cooling devices for directing heat away therefrom, the adaptor  200  can include built in components to manage the removal of heat that the adaptor  200  collects from the heat sink. According to an embodiment, one or more pipes is embedded within the adaptor  200 . The pipes can contain liquid or other fluid which can flow through the pipes out of the adaptor  200 , thereby removing the heat therefrom. An arrangement of pipes within the adaptor  200  may also be part of a gas compression system to provide cooling due to fluid phase change. The energy requirements of a phase change from a liquid to a gas within the pipes efficiently draws heat away from the adaptor. 
         [0031]    For situations where the product to be cooled must be contained within a sealed enclosure, the heat sink adaptor can provide a physical cooling ‘bridge’ to the outside of the enclosure where a greater supply of air, liquid or other cooling medium can be available. 
         [0032]    The adaptor  200  may be fabricated from any suitable material or combination of materials. The material(s) should offer good thermal conductivity. For example the adaptor may comprise aluminium, copper, other ferrous or non-ferrous metals or glass. 
         [0033]    The particular adaptor described above and shown in  FIGS. 2 to 4  is a cold plate adaptor which is designed to fit with a finned heat sink as shown in  FIG. 1  which has substantially rectangular fins extending generally at a right angle from a base of the heat sink. However other adaptors can be designed and can operate according to the same principles in conjunction with other designs of heat sink. For example if the heat sink has flared or irregularly angled fins projecting from its base, the size, shape and orientation of the projections of the adaptor can be appropriately configured to match the flared or irregularly angled fins, so that the projections fit well into the gaps between adjacent fins and have a large amount of surface area in common with the fins to provide thermal contact surfaces for conduction of heat from the heat sink to the adaptor. Similarly, if the heat sink comprises another type of protrusion, for example pins extending from the base, the adaptor can include suitably sized and shaped projections to match those protrusions. For example cylindrical projections, into which the pins of the heat sink can insert for conduction of heat from the heat sink to the adaptor, can be provided. Alternatively, the adaptor could comprise a substantially solid block with slots or channels therein into which the protrusions from the heat sink can insert. 
         [0034]    As mentioned above, the base of the adaptor can be fitted to or can otherwise contact an external component such as another cooling device in any appropriate manner. For example, pipes or other conduits may be used to transfer heat from the adaptor  200  to an air cooled heat sink somewhere else, a water cooled system, a condensed gas system or any other suitable cooling device. As a result, a conventional heat sink (when used with the adaptor  200 ) can be more versatile. For example, instead of using forced air for cooling a conventional heat sink in environments where the air used contains particulates that are likely to clog the fins over time and thus reduce efficiency of the heat sink, the adaptor can be mated into the gaps between the fins of the heat sink and used to channel heat away from the heat sink, without needing to force particle-filled air around the heat sink. And in environments where a high degree of protection is required from water, gas or dust necessitating installation of the heat sink in a sealed enclosure, limiting the supply of cool air to supply to the heat sink and so reducing its efficiency, the adaptor can be used to remove heat from the heat sink using conduction instead of convection and channel it elsewhere without replacing the existing heat sink. 
         [0035]    So it can be seen that the adaptor is highly useful for updating existing cooling systems which rely on conventional heat sinks and making them more useful and efficient without having to replace the heat sink. Therefore the adaptor is a cost effective solution which avoids physical disruption to existing systems. It can also be conveniently manufactured in conjunction with a new heat sink, hence increasing the heat sink&#39;s potential usefulness. The adaptor can include internal cooling components and/or can connect to external cooling components to direct heat away from the heat sink and associated heat source in any suitable manner, depending on the particular application or environment in which it is to be used. Therefore the adaptor enables an existing device which includes a heat sink to be used in a wider range of environments. 
         [0036]    Whilst some specific examples of the uses of heat sinks have been given above, the adaptor described herein can be used in conjunction with a heat sink for any appropriate application in which heat must be transferred away from the heat source. The adaptor can be of any suitable size, shape and configuration in order cooperate with the heat sink physically and to meet the requirements for thermal transfer therefrom. The adaptor can be designed, manufactured and/or supplied with a co-operating heat sink, or can be retrofitted to an existing heat sink. By enabling heat to be conducted out of a conventional heat sink, rather than relying on convection, and by doing so in a simple and straightforward manner which does not require permanent adaptation of the existing heat sink, a highly useful and practical solution is provided by the adaptor.