BRIEF DESCRIPTION OF THE DRAWINGS
Some embodiments of the present invention will now be described by way of example only, and with reference to the accompanying drawings, in which:
FIG. 1 schematically illustrates in cross-section fan apparatus in accordance with the invention;
FIG. 2 schematically illustrates in cross-section a heat pipe included in the apparatus of FIG. 1;
FIG. 3 schematically illustrates another embodiment of the invention;
FIG. 4; schematically illustrates a further embodiment of the invention in which encapsulant protects the motor;
FIG. 5 schematically illustrates telecommunications apparatus including a fan tray;
FIG. 6 shows in greater detail part of the apparatus shown in FIG. 5; and
FIG. 7 schematically illustrates another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, fan apparatus 1 includes an external-rotor motor 2, having rotor laminations 3, stator laminations 4 and stator windings 5 arranged to rotationally drive a motor shaft 6 about the axis X-X. The shaft 6 is mounted in a bearing arrangement, consisting of first and second motor bearings 7 and 8 respectively. The fan apparatus 1 includes an impeller having a plurality of blades 9. The blades 9 are mounted on a hub housing 10, which is carried by the shaft 6, such that, when the motor 2 drives the shaft 6, the blades 9 rotate to move ambient air in the direction shown by the arrow.
The shaft 6 almost wholly consists of a heat pipe 11, which is shown in greater detail in FIG. 2. The heat pipe 11 comprises a hollow steel tube with its inner surface carrying a sintered wicking structure 12. A small quantity of water, sufficient to saturate the wicking structure 12, is also contained within the tube. The heat pipe 11 has an evaporator section 13, which is located in the region of the first and second bearings 7 and 8, and a condenser section 14. The condenser section 14 is extensive in the direction of the front of the motor 2, where the blades 9 are located.
Heat generated at the bearing arrangement 7, 8 causes water to vaporize at the evaporator section 13. Vapor travels along the heat pipe 11 to the condenser section 14, which is cooler than the evaporator section 13. The vapor condenses and returns to the evaporator section 13 via the wicking structure 12. This mechanism causes heat to be transferred away from the first and second bearings 7 and 8, so that they are maintained at a lower temperature than would be the case if no heat pipe were included.
In this embodiment, a heat-dissipative member, configured as a plate 15, is joined to the heat pipe 11 at the condenser end of the shaft 6. This increases the available surface area by which heat transfers from the condenser section 14 into the ambient air. However, although advantageous, inclusion of a plate or other means additional to the heat pipe to enhance heat transfer is not essential to benefit from the invention.
In another embodiment, the shaft 6 is only partly constituted by heat pipe. For example, one bearing of a bearing arrangement might tend to reach a higher temperature than another bearing, or bearings, included in the arrangement, in which case, only the bearing which runs hotter may require cooling. In another embodiment, the bearing arrangement may include only a single bearing.
In another embodiment, not illustrated, the heat pipe is extensive from the motor in the opposite direction to that shown in FIG. 1. In this embodiment, the evaporator section is located at the bearing arrangement, as in the assembly shown in FIG. 1, and the condenser section is extensive at the rear of the fan assembly 1, on the other side of the motor 2 to the blades 9. A heat-dissipative member, such as the plate 15 shown in FIG. 1, may also be used in such an alternative embodiment.
With reference to FIG. 3, in which similar parts to those in FIG. 1 are given the same reference signs, the shaft 6 is substantially wholly constituted by a heat pipe 16, which extends from the bearing arrangement 7, 8 to beyond the hub housing 10 in one direction and beyond the motor 2 in the other direction. The part of the heat pipe 16 near the bearings 7 and 8 acts as an evaporator section 17 and the two extremities are condenser sections 18 and 19, both of which act together with the evaporator section 17 to provide heat transfer in opposite directions away from the bearings 7 and 8 as shown by the arrows. Heat-dissipative members 20 and 21 are fixed to the heat pipe 16 at either end. In other embodiments, either one, or both, of the heat-dissipative members 20 and 21 are omitted.
In another embodiment having two condenser sections, the heat pipe has two corresponding evaporator sections, each being associated with a respective condenser section, and there is no continuous path between them. In this case, the heat pipe functions as two discrete components.
With reference to FIG. 4, a fan apparatus 1 includes encapsulation material 21 around the windings. The blades 9 are of aluminum and no separate heat-dissipative member is included in this embodiment, the blades 9 having good thermal conductivity.
With reference to FIG. 5, a telecommunications apparatus includes a cabinet 22 housing electronic equipment 23 racked on shelves 24. A fan tray 25, on which is mounted a plurality of fans 26, is located at the top of the cabinet 22. Each of the fans 26 includes a heat pipe in accordance with one of the previously described embodiments. The fans 26 operate to draw air over the electronic equipment 23 in a pull-through system.
One of the fans is shown in greater detail in FIG. 6. It includes a heat pipe 27, which is extensive from the motor bearing arrangement 28 to the rear of the motor 29 where it is thermally connected via an additional bearing 30, or a bushing, to the cabinet wall 31. This gives additional mechanical security as well as providing a path for cooling. A mounting bracket 32 provides the main structural support for the fan.
Operation of the fans may be further enhanced by applying active cooling to the cabinet housing. For example, a refrigeration panel 33 may be included.
In another embodiment, a fan tray may be included at the base of the cabinet, as shown in a broken line at 34 in FIG. 5, in a push-through system, in addition to, or instead of, the pull-through system.
FIG. 7 illustrates another embodiment of the invention that is similar to that shown in FIG. 1 except that in this case, a heat-dissipative member 35 located in front of the hub 10 is shaped so as to deflect airflow and thus reduce noise.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Patent Application
20070286744
