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To finish with this description, the very heart of this fan: the bearing, which works with hydrodynamic lubrication. To understand this concept better, it is important to know first that friction is produced when two surfaces in contact have a relative displacement. This friction will wear down both surfaces and in the end, it will make them useless.
For fan manufacturing, it is very common to use bearings or ball bearings. Each of them has its own pros and cons, but the outcome is always the same: the wear down of the surfaces involved.
Ball bearings work precisely with components that revolve around each other. In this way, friction is reduced significantly but because of the geometrical configuration of the two races, the ball bearings cannot revolve perfectly around the races at the same time and, as a result, the wear down is not completely avoidable. Elastohyrodynamic lubrication is applied in this case.
Bearings generally work with boundary lubrication. In this type of movement, the contact and friction between surfaces is the highest.
Finally, there is the hydrodynamic lubrication. Here the contact between the two surfaces is nonexistant. Let's have a quick look at how this is achieved.
If we have two flat surfaces -as in the picture above- moving one against the other, with a fluid of a certain viscosity between them, we'll see, due to the effect of the fluid's viscosity and the friction between it and the two surfaces, that the fluid in contact with each of the surfaces will have no movement regarding them. But, as both surfaces have movement between themselves, we'll have as a result, a movement of the fluid with a speed distribution similar to the one shown in the drawing.
If the two flat and parallel surfaces formed an angle between them instead, as it happens, for example, in an axle that, by the action of its own weight and what it supports, has moved from the relative center that shares with the bearing, the fluid would not be able to move so freely -as it is possible to see in the picture below.
Consequently, when both surfaces relatively move by the effect of rotation, the drag generated in the fluid creates a positive pressure in the lower part of the axle -to be more precise, in the narrower part, which is similar to a wedge- which makes the axle move upward. The benefit is evident: both parts are not in contact anymore, since there is only lubricant fluid between them.
This is makes the spinning frictionless, giving us an excellent noise level and practically no wear down, which allows Arctic Cooling to offer a six year warranty for this product.
So far we've got an interesting set of technical solutions: absence of lateral frame, redesigned fan blades, plastic reinforced fiberglass, vibration absorving supports and to finish with, lack of friction between the rotor and stator. This means more comfort to the user. With the increasing power consumption in today's PCs, as we've seen in previous articles and also taking into account that even the best of coolers needs air in an appropriate temperature, the tendency is to add more and bigger fans to the case. As a consequence, our peaceful study now has turned into the cockpit of an Apache Longbow instead of being a place where we could concentrate and work comfortably.
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