A FAN HAVING COMBINED AXIAL-RADIAL IMPELLER GEOMETRY AND PRODUCTION METHOD THEREOF

Technical Field

The invention relates to a fan having a combined axial-radial impeller geometry and production method thereof.

Especially, the present invention relates to an improved impeller design for a fan combined as axial and radial flow types and method for providing smooth transition flow geometry and economic production thereof by using a plurality of short bladed-linear-side core pair from sides and rotating-top core from top together instead of using only long bladed-rotating-side core.

Prior Art

Fan; it is a device that provides the flow of fluid by creating a pressure difference. Impeller, which is the moving element of the fan, does work on the fluid and gives it static and kinetic energy. The ratio of these static and kinetic energies to each other depends on the type of fan. Basically, fans are devices used to produce fluid flow. The fans are classified according to impeller design and are generally of two types, axial and radial.

Axial and radial type fans have different features and are selected according to their usage areas. Axial fans are fans that provide high fluid flow at low pressure. Small resistance changes in the system cause large flow losses compared to the radial fan. Radial fans apply centrifugal force to the fluid for changing the direction of fluid from axial to radial direction and provide more pressure increase compared to axial fan.

When axial and radial types are combined together; provides higher fluid flow than radial fans, no unstable zone occurs on the fan performance curve, it works with higher efficiency.

In the conventional production method of fans, long bladed-rotating-side core pair with long blades from the sides of fan are used. In this case, it is difficult and costly to provide a smooth flow geometry on the impeller when long bladed-rotating-side core pair are used. Besides rough surfaces may occur on the impeller of fan (Molds of appropriate sizes are called as 'cores’ for the parts of the part to be poured that are desired to be empty). By using short bladed-linear-side core pair and rotating-top core together in the present invention, the transition of the impeller from axial to radial is smoother geometry and less costly.

The document US20140086767A1 discloses also an impeller comprising a hub configured to be rotated on a central axis, a shroud formed to be opposed to the hub in a direction of the central axis and having a central opening serving as a fluid inlet, and a plurality of circumferentially equidistant spaced blades interleaved between the hub and the shroud. When a mating face of the shroud with each of the blades is divided into a radially inward region and a radially outward region, and a mating face of each of the blades with the shroud is divided into a radially inward region and a radially outward region, a given weld range is set only in the radially inward region of the mating face of the shroud with each of the blades and the radially inward region of the mating face of each of the blades with the shroud. However, mixed-flow fan and the production method are not disclosed in said invention.

Objectives and Short Description of the Invention

An objective of this invention is to present an improved impeller design for a fan combined as axial and radial flow types, and method for providing smooth transition flow geometry and economic production thereof by using a plurality of short bladed-linear-side core pair from sides, and rotating-top core from top together instead of using only long bladed-rotating-side core.

Present invention is a production method for a fan having a combined axial-radial impeller geometry, and in order to provide mentioned impeller with smoother geometry and thus, to increase performance by facilitating the process of removing the product from the mold; the production method comprises following step: forming impeller structure which starts axial way at the top side where the fluid enters and becomes radial at the lower side where the fluid outs, by using at least one rotating-top core from top, and at least one short bladed-linear-side core from sides of the fan.

Present invention is a fan having mixed flow impeller geometry, and it comprises; impeller structure which starts axial way at the top side where the fluid enters and becomes radial at the lower side where the fluid exits, by using at least one rotating-top core from top, and at least one short bladed-linear-side core from sides.

Present invention is a fan having combined axial-radial impeller geometry and wherein helix pitch of the impeller back surface is longer than the mold exit pitch in the range of 2-5% and helix pitch of the impeller front surface is shorter than the mold exit pitch.

Description of the Figures

In Figure 1 a, a perspective view of the present innovative fan is shown.

In Figure 1 b, a perspective view without upper frame of the present innovative fan is shown.

In Figure 2, a top view of present innovative fan is shown.

In Figure 3, a cross-sectional view of the innovative fan, taken along the line A-A given in FIG. 2 is shown.

In Figure 4, a side view of the present innovative fan is shown.

In Figure 5a, a cross-sectional view of the present innovative fan, taken along the line B-B given in FIG. 4 is shown.

In Figure 5b, a perspective view of the present innovative fan according to the FIG. 5a.

In Figure 6a, a cross-sectional view of the present innovative fan, taken along the line C-C given in FIG. 4 is shown.

In Figure 6b, a perspective view of the present innovative fan according to the FIG. 6a.

In Figure 7a, a cross-sectional view of the present innovative fan, taken along the line D-D given in FIG. 4 is shown.

In Figure 7b, a perspective view of the present innovative fan according to the FIG. 7a.

In Figure 8a, a top perspective view of the present fan production process is shown.

In Figure 8b, a bottom perspective view of the present fan production process is shown.

In Figure 9a, a top perspective view of the conventional fan production process is shown according to the prior art. In Figure 9b, a bottom perspective view of the conventional fan production process is shown according to the prior art.

Reference Numbers

I Fan

10 Housing

II Upper frame

12 Flat floor

13 Wall

20 Impeller

21 Starting point

22 End point

23 Curved surface

24 Cross-section surface

25 Impeller front surface

26 Impeller back surface

30 Bushing

40 Rotating-top core

41 Short bladed-linear-side core

42 Long bladed-rotating-side core

I Fluid inlet

E Fluid outlet

F1 Front top arc length

F2 Front bottom arc length

B1 Back top arc length

B2 Back bottom arc length

Detailed Description of the Invention

The present invention relates to a fan (1) with an improved impeller (20) design combined as axial and radial flow types and, a method for smooth flow geometry and economic production thereof by using short bladed-linear-side core (41 ) pair and rotating-top core (40). The present innovative fan (1 ) generally comprises; impeller (20), curved surface (23), bushing (30) and housing (10). The housing (10) is a structure comprising an upper frame (11 ) with an open top side so that the fluid can enter from here, a flat floor (12) and a plurality of walls (13) formed on the along sides of fan (1 ) between said upper frame (11 ) and flat floor (12) so that the fluid can exits from here. Said walls (13) form the fixed part of the fan (1 ) with geometry as a continuation of the impeller (20) and mentioned walls (13) connects said upper frame (11 ) and said flat floor (12). There is at least one curved surface (23) that curves down from the level of the said upper frame (11 ) to the flat floor (12). The mentioned curved surface (23) helps to redirect or discharge fluid radially thanks to its curved geometry. Bushing (30) is formed in the middle of the fan (1 ) and assembled into a shaft to rotate the impeller (20).

The present innovative fan (1 ) has a design that combines the radial and axial impeller (20) structure. This structure has many benefits compared to axial and radial flow types. The impeller (20) starts axial way at the top side where the fluid enters and becomes radial as the impeller (20) approaches the flat floor (12). Thus here, the fluid is taken inside axially and is given out radially. In order to provide a smoother transition flow geometry of impeller (20) as passing from axial to radial form, short bladed-linear-side core (41 ) pair and rotating-top core (40) are used together in the present invention, unlike the prior art method requiring long bladed-rotating-side core (42).

As seen figure 1 b, impeller front surface (25) and impeller back surface (26) of the impellers (20); front arc lengths and back arc lengths are specified. Said impeller front surface (25) arc lengths consists of front top arc length (F1 ) and front bottom arc length (F2). Said impeller back surface (26) arc lengths consists of back top arc length (B1 ) and back bottom arc length (B2). The back arc lengths are longer than front arc lengths. In other words; back top arc length (B1 ) is longer than the front top arc length (F1 ), and the back bottom arc length (B2) is longer than the front bottom arc length (F2). This is because helix pitch of the impeller back surface (26) is longer than the helix pitch of the impeller front surface (25). Besides, there is mold exit pitch of impeller (20). The mold exit pitch is an imaginary structure. Also, mentioned mold exit pitch is located between impeller front surface (25) and impeller back surface (26). Therefore, helix pitch of the impeller back surface (26) is longer than the mold exit pitch in the range of 2-5% and helix pitch of the impeller front surface (25) is shorter than the mold exit pitch.

The sections in Figure 5a, Figure 6a and Figure 7a were taken respectively from lines B-B, C-C, and D-D shown in Figure 4. As seen from these figures, the distance between the starting point (21 ) and the end point (22) differs for each section of mentioned impeller (20). As seen the sections of the figures, descend from upper frame (11 ) to the flat floor (12), the distance between the start point (21 ) and the end point (2) decreases. In other words, on the way from the section taken from the B-B line to the section taken from the D-D line the distance between the start point (21 ) and the end point (22) decreases. This is an indication of the transition of the present innovative impeller (20) from axial form to radial form as approaching from the upper frame (11 ) to the flat floor (12). As you go up from the flat floor (12) to the upper frame (11 ), the distance between the start point (21 ) and the end point (22) increases and the helix pitch difference becomes more evident.

The views in Figure 5b, Figure 6b, and Figure 7b are perspective views of the sections in Figure 5a, Figure 6a, and Figure 7a, respectively. Also, line shaded area represents of crosssection surface (24) in perspective views.

As seen from the present innovative production process given in figure 8a and figure 8b, short bladed-linear-side core (41 ) pair and rotating-top cores (40) are used. The rotating-top core (40) enters from the upper part of the fan (1 ) and forms the inner part of the impeller (20) geometry. At the same time, the short bladed-linear-side core (41 ) pair enter from the side of the fan (1 ) and form the walls (13) with geometry which are the continuation of the said impeller (20). Thus, the short bladed-linear-side core (41 ) pair and rotating-top core (40) are formed simultaneously the present innovative impeller geometry which starts axial way at the top side where the fluid enters and becomes radial as the impeller (20) and walls (13) approaches the flat floor (12).

As seen from the conventional production process of the fan (1 ) in figure 9a and figure 9b, only the long bladed-rotating-side core (42) pair is used, unlike the present innovative method using both the short bladed-linear-side core (41 ) pair and rotating-top core (40) together. Said previous prior art production method does not make it possible to create the desired flow geometry on the impellers (20) and walls (13).