EURO-ECO 2010 Hanover 2 - 3 Dezember 2010	Environmental, Engineering - Economic and Legal Aspects for Sustainable Living
	European Academy of Natural Sciences, Hanover European Scientific Society, Hanover University of Bremen, Bremen

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Axial-flow fans find a wide application in the equipment of dust catching and pneumatic transport, in mechanisms for cooling machines and their units, in appliance cooling, in system units of personal computers, in compressors of refrigerating plants, in ventilation networks and air-conditioning, in means of transport and hovercrafts, for screen airfoil boats and ram wing machines, in airship movers and so on.

The majority of axial-flow fans all over the world are produced with a ring guide casing simultaneously protective in which chamber axially symmetric is located an impeller made of two and more blades.

Now in Russia and in the State Technical University of Orel it has been established that all known axial-flow fans produced with a protective ring casing function energy-wise ineffective.

Thus, at patent researches it has been established that the closest engineering solution may be the axial-flow fan (Cooler) type A65061-002, 020223P, for computers of model Pentium – 4 “Intel” destined for cooling this microprocessor. The shortcoming of such a structure in the known axial-flow fan consists in that during rotation of its impeller all seven concave blades with rectilinear front and rear edges with their effective areas tilted at a sharp angle to the plane of rotation push a certain volume of air grasp with the front edges along and round the axis of rotation thus creating swirling air flow which moves at high speed along the axis of rotation and at the same time from under every blade some part of air swirled shift radially at the expense of the created centrifugal force and strike at high speed against a statically motionless inner cylindrical casing wall. At such a blow against the inner casing wall the whole mass of a radial flow as if bifurcated. And at the same time its one part turns towards the motion of the main axial flow, and the other part of this radial flow turns against the main axial flow and hence creates a breaking effect slowing down that kinetic energy which it obtained at the action of centrifugal force at the radial motion of air flow from the bush to the cylindrical casing wall. The above mentioned breaking effect contributes to the increase of energy consumption at the propeller rotation and on the whole, to axial fan efficiency.

In the test run carried out in OrelSTU with the fan type BH-2 of the Soviet production proved that the application of the impeller with blades of new design allows power consumption reducing in the mentioned axial fan by 1.27%.

This technical invention allowed obtaining a patent for an invention (Patent of Russia 2232920).

In a new invention this shortcoming is excluded due to that end trailing edges of all propeller blades are bent towards the work surfaces at an angle of ninety degrees keeping an annular gap size between an inner cylindrical surface of a guide casing and perimeters of clinches of each blade and the height of bent trailing edges of all blades with respect to their work surfaces is the same and makes a definite size.