GB2413901A

GB2413901A - Cooling apparatus

Info

Publication number: GB2413901A
Application number: GB0410097A
Authority: GB
Inventors: Neil James Parkin
Original assignee: Agilent Technologies Inc
Current assignee: Agilent Technologies Inc
Priority date: 2004-05-06
Filing date: 2004-05-06
Publication date: 2005-11-09
Also published as: GB0410097D0

Abstract

At least one cooling apparatus 40 is provided for use in a communications device 5 which receives modules 30. The cooling apparatus is the same size as a module so that it can be received by the communications device in place of a module. The communication device may comprise a PCB 10 which receives the modules/cooling apparatus. The cooling apparatus may comprise heat pipes (52, Fig 2a) or fans (64, Fig 3). The cooling apparatus may conform to the Small Formfactor Pluggable (SFP) Transceiver specification INF-8074i.

Description

241390 1 - 1

COOLING APPARATUS

The present invention relates to cooling apparatus, and in particular to an apparatus for cooling communications devices.

SFP (Small Formfactor Pluggable) Transceivers are commonly used in communications devices such as routers, switches, WDM terminal equipment, etc. The size and form of an SPF transceiver is defined within the INF8074i specification (see ftp://ftp.seagate.com/sff) so that a transceiver conforming to the specification can be used with any suitable communications device. The specification also defines the power supply used by the transceiver and basic management functions, for example the transceiver response when being inserted into or removed from an operating communications device.

Frequently a number of SUP transceivers will be mounted on a PCB within a housing of a communications device, with a number of similar devices being stored within a rack. As the transistor density of semiconductor devices increases, as well as the frequency at which such devices are operated or switched, the heat generated by each transceiver increases.

It is an acknowledged problem that excessive heat generation can cause operational problems for the transceivers, with a decrease in performance and/or a decrease in transceiver reliability being observed. This problem is addressed to a limited extent by the use of one or more fans within;a housing to draw air across the transceivers, leading toga cooling of the transceivers. This approach is nod always '-I effective as hot spots may develop within the housing, which,' ._ - 2 can lead to a deterioration in transceiver performance or damage being caused to the transceiver.

According to a first aspect of the present invention there is provided a cooling apparatus configured for use in a communications device, the communications device being configure to receive one or more modules of a predetermined size characterized in that the cooling apparatus comprises the predetermined size of a module for the communications device.

The cooling apparatus may comprise one or more heat pipes, and may comprise a plurality of heat pipes, each of the heat pipes being separated from one or more adjacent heat pipes.

Alternatively, the cooling apparatus may comprise a first plurality of heat pipes and a second plurality of heat pipes, wherein the first plurality of heat pipes is configured to conduct heat in a first direction and the second plurality of heat pipes is configured to conduct heat in a second direction.

The cooling apparatus may comprise one or more fans. The fan, or fans, may be received within a conduit. The conduit may comprise one or more apertures.

The cooling apparatus may conform to the Small Formfactor

Pluggable Transceiver specification INF-8074i.

The invention will now be described, by way of example only, with reference to the following Figures in which: Figure 1 shows a schematic depiction of communications device comprising a plurality of cooling modules - 3 according to the present invention; Figure 2 shows a schematic depiction of a cooling module according to a first embodiment of the present invention; and Figure 3 shows a schematic depiction of a cooling module according to a second embodiment of the present invention Figure 1 shows a schematic depiction of communications device comprising a PCB 10, which is located within a communications device housing 20, and receives a plurality of transceivers 30. The PCB 10 further comprises a plurality of cooling modules 40 which have the same form factor as the transceivers and thus the cooling modules can be received by the PCB. The cooling modules may take one or more of a number of forms (see below) but act to cool the active transceivers in the housing.

The cooling module(s) may conform to the SPF transceiver INF-

8074i specification, or to any other transceiver

specification. It will be understood that the cooling module(s) could be used with other electronic or opto- electronic devices, such as transceivers, receivers, signal processing units, etc. In one embodiment of the present invention, the cooling modules comprise an array of heat pipes. These heat pipes contain a volatile liquid that can be used to transport heat from the interior of the housing to the exterior, where the removed heat can be dissipated within a much greater volume of air and additionally air-cooling and/or air-conditioning can be used to cool the air. Referring to Figure 2, Figure 2a shows a schematic depiction of a cooling module 50 that - 4 comprises a plurality of heat pipes 52 that run along the entire length of the cooling module.

Figure 2b shows a schematic depiction of a further embodiment of a cooling module 50' that comprises a first and second plurality of heat pipes 54, 56. The heat pipes are supported by framework 51 and are arranged such that there are air gaps 58 provided between adjacent heat pipes. The air gaps increase the surface area of the heat pipes that are in contact with the heated air and thus increase the efficiency of the cooling module. There is also an air gap between the first plurality of heat pipes and the second plurality, with the heat pipes being configured so that heat is transferred in different directions (as indicated by the arrows), so that heat can be removed from the centre of a housing and vented from both the front and the rear of the housing. It will be understood that the cooling module 50 arrangement shown in Figure 2a may be modified to include air gaps between adjacent heat pipes whilst only using a single plurality of heat pipes 52.

In a second embodiment of the invention, the cooling module comprises one or more fans, which act to move hot air from the interior of the housing to the exterior, causing cooler air to be drawn into the interior of the housing. Figure 3a shows a schematic depiction of a side view of such an arrangement with the cooling module 60 comprising a base 62 supporting one or more fans 64. It will be understood that a combination of one or more of these fans may be used, with fan 64a being used to draw air into the housing at one end of the cooling module and fan 64c being used at the other end of the cooling module to expel air from the housing. Fan 64b may be also used to increase the flow of air through the cooling module and it will be understood that more than one fan may be located along the length of the cooling module 60.

In a further embodiment, which is schematically depicted in Figure 3b, the cooling module 60' comprises a conduit 66 that provides some mechanical protection and comprises a number of apertures 68 that enable air from the interior of the housing to be vented to the interior through the conduit. The chimney effect provided by such a conduit should increase the efficiency of the cooling module. If the cooling module 60' or 60'' (see below) is to be fully compliant with the SFP specification, or another specification, then the dimensions of the conduit must be selected to meet the specification requirements. It will be understood that it may be possible to add apertures to the conduit, or change one or more conduit dimensions, so that the cooling module can still interface with a PCB designed to receive an SFP transceiver even though the module does not strictly meet the SFP

specification.

Figure 3c shows a further embodiment of the present invention in which air is expelled from the housing via both ends of the cooling module 60''. The cooling module 60'' comprises a conduit 66 that comprises one or more apertures 68 in its top and/or sides. Fans 64a and 64c are both configured to expel air from within the housing and thus heated air is drawn into the conduit from within the housing, through the apertures, and then expelled from the housing. It will be readily understood that there will need to be additional openings in the housing to enable cool air to enter the housing at some point so that this embodiment can function effectively. - 6

By appropriate choice of location and/or size of the apertures 68, the flow of air through the housing can be selected so as to provide a desired airflow and cooling effect within the housing, for example the airflow may be predominantly towards both sides of the module. If a module is designed to be used at one end of a housing then apertures may be provided on a single side of the conduit.

It will be understood that the arrangement shown in Figure 1 is figurative and that one or more cooling modules could be used in conjunction with one or more SUP transceivers (up to the capacity of the housing) dependent on the heat being generated by the transceivers and the cooling capabilities of the cooling modules. The cooling modules according to the present invention may be used as the primary cooling for a communications device such as a router or may be used to supplement the conventional cooling provided by fans. The cooling modules may also be used as an emergency repair in the event that a fan fails or the temperature of a device exceeds a threshold, as a cooling module can be inserted without needing to power down the communications device. If a communications device is experiencing intermittent faults which are believed to be caused by overheating, then an appropriate cooling module may be installed in order to assist in the diagnosis of the fault.

Typically the communications devices that comprise the SFP transceivers and could be used with the cooling modules of the present invention are used in rooms or enclosures that are air conditioned, and typically a number of devices will be co-located, often in equipment racks. The cooling modules can be configured such that cool air is drawn in from one side of an equipment rack and then the heated air is vented from the other side of the rack. This may be combined with the intake and outtake of the air conditioning system such that the air conditioning system emits cooled air into the region from which air is drawn into the communications devices. Furthermore, an intake of the air conditioning system may be located so that hot air expelled from the communications devices can be efficiently removed.

It will be readily understood that a cooling module may comprise features described above with reference to Figure 2 combined with features described above with reference to Figure 3, for example using fans to direct air flow onto heat pipes. It will be understood that further cooling modules may be used in addition or as an alternative to heat pipes and/or fans, such as heat sinks, thermoelectric coolers, etc. It will also be understood that the heat pipes need not comprise a cylindrical shape and may be serpentine or have a planar construction. - 8 -

Claims

1. A cooling apparatus (40) configured for use in a communications device (5), the communications device being configured to receive one or more modules (30) of a predetermined size, characterized in that the cooling apparatus (40) comprises the predetermined size of a module for the communications device.

2. A cooling apparatus (50) according to claim 1, wherein the cooling apparatus comprises one or more heat pipes (52).

3. A cooling apparatus (50') according to claim 1 or claim 2, wherein the cooling apparatus comprises a plurality of heat pipes (54), each of the heat pipes being separated from one or more adjacent heat pipes.

4. A cooling apparatus according to claim 2 or claim 3, wherein the cooling apparatus (50') comprises a first plurality of heat pipes (54) and a second plurality of heat pipes (56), wherein the first plurality of heat pipes is configured to conduct heat in a first direction and the second plurality of heat pipes is configured to conduct heat in a second direction.

5. A cooling apparatus according to any preceding claim, wherein the cooling apparatus (60) comprises one or more fans (64).

6. A cooling apparatus (60') according to claim 5, wherein the one or more fans (64) are received within a conduit (66). - 9

7. A cooling apparatus according to claim 6, wherein the conduit (66) comprises one or more apertures (68).

8. A cooling apparatus according to any preceding claim, wherein the cooling apparatus (40) conforms to the Small Formfactor Pluggable Transceiver specification INF-8074i.