WO2014135396A1

WO2014135396A1 - Fan unit

Info

Publication number: WO2014135396A1
Application number: PCT/EP2014/053608
Authority: WO
Inventors: Börje Nilsson
Original assignee: Fergas Ab
Priority date: 2013-03-08
Filing date: 2014-02-25
Publication date: 2014-09-12

Abstract

A fan unit (1) with a housing (2) enclosing a first space (7a), which has a first inlet (8a) and a first outlet(9a), and a second space (7b), which has a second inlet (8b) and a second outlet (9b). The fan unit (1) also has a fan wheel (12) arranged inside the second space (7b) and a motor (16) for driving the fan wheel (12). The first outlet (9a) and the second inlet (8b) provide a passage for air to flow between the first space(7a)and the second space (7b). The first inlet (8a) provides a passage for air to flow into the first space (7a) along a first direction which is substantially perpendicular to a rotation axis of the fan wheel (12). The second outlet (9b) provides a passage for air to flow out from the second space (7b) along a second direction which is substantially perpendicular to the rotation axis of the fan wheel (12).

Description

FAN UNIT

Technical field

The present disclosure relates to a fan unit. More specifically, it relates to a centrifugal type fan unit.

Background

Different types of fans are known and used for a variety of industrial and domestic purposes. Typical applications include heating, cooling and ventilation.

A widely used type of fan is the crossflow fan which operates by drawing a fluid into the rotating fan wheel along a radial direction. A number of blades, which are arranged on the fan wheel around its rotation axis, subsequently push the fluid along a tangential direction of the fan wheel through an outlet.

An example of a crossflow fan is disclosed in EP 1571397 B1 . The disclosure relates to heaters, especially for electrical fireplaces.

The required characteristics of the outflow of fluid depend on the application. For example, crossflow fans are commonly used in applications requiring a wide flow of air. Some applications require a high-pressure outflow or a uniform outflow. The size of the fan unit and its noise level are also important considerations in many applications.

It is possible to improve existing fan units with respect to the trade-off between size, noise level and capacity to generate a high-pressure flow of air which is wide as well as uniform..

Summary

The objective is to provide an improved or alternative fan unit. Aspects of particular interest are the size and noise level of the fan unit as well as its capacity to generate a wide, uniform and high-pressure flow of air. The invention is defined by the independent claims. Embodiments are set forth in the dependent claims and in the description and drawings.

According to a first aspect, there is provided a fan unit with a housing enclosing a first space, which has a first inlet and a first outlet, and a second space, which has a second inlet and a second outlet. The fan unit also has a fan wheel arranged inside the second space and a motor for driving the fan wheel. The first outlet and the second inlet provide a passage for air to flow between the first space and the second space. The first inlet provides a passage for air to flow into the first space along a first direction which is substantially perpendicular to a rotation axis of the fan wheel. The second outlet provides a passage for air to flow out from the second space along a second direction which is substantially perpendicular to the rotation axis of the fan wheel.

The expression "enclosing" should be understood to mean that air can flow between the interior and the exterior of the housing substantially only through the first inlet and the second outlet.

By two directions being "substantially perpendicular" is meant that they are perpendicular or that the angle between them differs from 90 degrees by less than ±15 degrees, less than ±10 degrees, less than ±5 degrees or less than ±1 degree.

Arranging the first inlet according to what is described above makes it possible to construct a compact and quiet fan unit. Moreover, this

arrangement enables the provision of a fan unit whose inflow and outflow are parallel, as well as a fan unit which can produce a uniform and high-pressure outflow with a large flow cross section.

The second outlet can be arranged at a first distance from a first major wall of the housing and at a second distance from a second major wall of the housing.

By a "major wall" is meant a substantially flat wall, the surface normal of which is substantially parallel to the rotation axis of the fan wheel,

The first and second major walls may be parallel.

The second space may have a first portion and a second portion which are juxtaposed along a direction parallel to the rotation axis of the fan wheel. This arrangement of the second space makes it possible to construct a fan unit in which air flows through the second outlet primarily due to a pressure difference between the second portion of the second space and the exterior of the housing; it is to a lesser extent the rotating fan wheel which pushes the air out from the housing. This arrangement enables the provision of a fan unit which generates an outlow which is more uniform and has a high-pressure.

The first portion of the second space can be formed substantially as a rectangular parallelepiped. The second portion of the second space can have substantially the shape of a rectangular parallelepiped or some other shape, such as a that of a triangular prism or tetrahedron. The shape of the second portion of the second space may be irregular.

That a space is formed "substantially as a rectangular parallelepiped" should be understood to mean that any deviations from the form of a rectangular parallelepiped do not exclude the space from being reasonably percieved as a rectangular parallelepiped The word "substantially" has an anlaogous meaning when referring to other shapes.

At least one of the first space and the second space may be formed substantially as a rectangular parallelepiped having an opening in one side, which opening forms the first inlet or the second outlet, respectively.

The first space and the second space may be separated along the axial direction of the fan wheel.

The surface normal of a flow cross section of the second outlet may be parallel with a radial direction of the fan wheel.

The width of second outlet may be at least 30 % of the diameter of the fan, alternatively at least 50 %, at least 75 %, at least 90 %, at least 100 % or at least 1 10 %.

A height of the flow cross section of the second space can be equal to or greater than a height of the cross section of the first space.

The second space flow cross section can have a width to height ratio of at least 3:2, at least 2:1 , at least 5:2, at least 3:1 , at least 4:1 , at least 5:1 , at least 6:1 or at least 7:1 . The ratio of the height of the second space flow cross section to the height of the first space flow cross section can be at least 1 :1 , at least 3:2, at least 2:1 , at least 5:2 or at least 3:1 .

The first space may present an inlet portion which tapers in flow cross section.

The first direction and the second direction can be substantially parallel.

By two directions being "substantially parallel" is meant that they are parallel or that the angle between them is less than ±15 degrees, less than ±10 degrees, less than ±5 degrees or less than ±1 degree.

The first direction and the second direction may be substantially perpendicular.

The fan wheel may be a centrifugal fan wheel.

The fan wheel may comprise backward-curved blades or backward inclined blades, as seen in a direction of fan rotation.

Using these types of blades may increase the capacity of the fan unit to generate a high-pressure outflow.

The motor can be mounted inside the second space.

The motor can be mounted outside the housing.

The motor can be an electrical motor.

The fan unit may consist essentially of the housing, the fan wheel and the motor.

The ratio of fan unit width to fan unit height is at least 2:1 , at least 5:2, at least 3:1 , at least 7:3, at least 4:1 or at least 5:1 . The fan unit height can be about 2-10 cm. The fan unit width can be about 50-300 mm or about 70-250 mm. The height of the fan unit can be about 30 % of its width, alternatively 10-50 %, 20-40 % or 25-35 %.

The second space may extend further than the first space, as seen in a direction of the flow out from the second space. For example, the outer radial edge of the fan wheel may extend further in the direction of the flow out from the second space than the first space.

Hence, attachment of a channel element for guiding the flow out from the fan unit is facilitated. A wall edge portion at the second outlet may present a protrusion which extends away from the direction of the flow out from the second space. Hence, this may further facilitate attachment of the channel element. Brief description of the drawings

The following drawings are included for exemplifying purposes.

Figure 1 shows a schematic side view illustration of a fan unit.

Figure 2 shows a schematic cross-sectional view along the line A-A in figure 1 .

Figure 3 shows schematically a different side view of the fan unit in figure 1 .

Figure 4 shows a fan unit with the second space arranged differently than in figures 1 to 3.

Figures 5 and 6 are schematic perspective views of another

embodiment of the fan unit 1 '.

Figure 7a is a top planar view of the fan unit 1 '.

Figure 7b is a sectional view taken along the line B-B in Figure 7a.

Description of embodiments

A fan unit 1 is described below with reference to figures 1 to 3. The expression "axial" refers to a direction which coincides with the line A-A of Figure 1 .

The fan unit 1 comprises a housing 2 which may have a bottom wall 3, a top wall 4 and side walls 5a, 5b, 5c and 5d. The housing 2 may be made of a thin sheet material, such as a metal, a polymer or plastics. The thickness of the housing 2 may be 0.2-3 mm or 0.5-2 mm.

The housing 2 may also have a partition wall 6 which separates a first space 7a from a second space 7b inside the housing 2. The upper and lower boundaries of the first space 7a in the axial direction may be defined by the top wall 4 and the partition wall 6, respectively. Similarly, upper and lower boundaries of the second space 7b may be defined by the partition wall 6 and the bottom wall 3, respectively. The first space 7a is connected to the exterior of the housing 2 via a first inlet 8a which may be defined by an opening in the side wall 5a. A second outlet 9b, which may be defined by an opening in the side wall 5b, similarly connects the second space 7b to the exterior of the housing 2. The surface cross sections of the first inlet 8a and the second outlet 9b, respectively, can be separated along the axial direction. They can also be separated along a direction which is perpendicular to the axial direction. An opening 10 in the partition wall 6 connects the first space 7a to the second space 7b. Hence, the opening 10 simultaneously constitutes a first outlet 9a (relative to the first space 7a) and a second inlet 8b (relative to the second space 7b).

The first inlet 8a may be rectangular, circular, elliptical or asymmetric.

The first inlet 8a has a height h,i which can be 5-70 % of the height h_a of the side wall 5a, alternatively 5-50 %, 10-50 %, 10-40 %, or 10-30 %. The first inlet 8a has a width w, which can be 30-100 % of the width w_a of the side wall 5a, alternatively 50-100 %, 50-99 % or 50-95 %.

The first space 7a presents an inlet portion 1 1 which may taper along the direction of the air inflow F, from a maximum height of h,i to a minimum height of h_i2. The ratio of h,i to h_i2 can be at least 10:9, at least 5:4, at least 4:3, at least 3:2, at least 2:1 , at least 5:2 or at least 3:1 .

The second outlet 9b may be rectangular, circular, elliptical or asymmetric. The second outlet 9b has a height h₀ which can be 5-70 % of the height h_b of the side wall 5b, alternatively 5-50 %, 10-50 %, 10-40 %, or 10-30 %. The second outlet 9b can extend along the axial direction from a distance from the bottom wall 3 to a distance l₂ from the top wall 4, where 0 < , I2 < h_b and I2 = h_b- h₀.The ratio of h₀ to h can be at least 1 :1 , at least 3:2, at least 2:1 , at least 5:2 or at least 3:1 . The height h₀ may be approximately equal to the difference h_b-h_i2. The second outlet 9b has a width w₀ which can be 30-100 % of the width w_b of the side wall 5b, alternatively 50-100 %, 50-99 % or 50-95 %.

The length of the first space 7a may be at least 50 % of the length l_t of the top wall 4, alternatively at least 60 %, at least 70 %, at least 80 %, at least 90 % or at least 100 %. The difference l_t - \<\ may be approximately equal to the thickness of the side wall 5b, the thickness of the sidewall 5a or the sum of the thicknesses of the side walls 5a and 5b. The length l₂ of the second space 7b may be at least 80 % of the length l_b of the bottom wall 3, alternatively at least 90 % or at least 100 %. The length l₂ may be 100-150 % of the diameter of the fan wheel 12, alternatively 101 -130 % or 101 -1 10 %.

The opening 10 in the partition wall 6 has a length l₃ and a width w₃ and may be rectangular, circular, elliptical or asymmetric. The ratio of to I3 can be at least 1 :1 , at least 2:1 , at least 3:1 or at least 4:1 . The ratio of o I3 can be at least 1 :1 , at least 2:1 , at least 3:1 or at least 4:1 .

The ratio of the area of the first inlet 8a to the area of the second outlet 9b can be at least 1 :1 , at least 5:4, at least 4:3, at least 3:2 or at least 2:1 .

A circular fan wheel 12 with blades 13 is mounted inside the second space 7b. The rotation axis of the fan wheel 12 coincides with the axial direction or makes an angle of less than 1 degree, less than 5 degrees, less than 10 degrees or less than 15 degrees with the axial direction. The fan wheel 12 can be visible through the second outlet 9b. The fan 12 wheel can be a centrifugal fan wheel. The fan wheel 12 may have a top plate 14, with one or several openings (not indicated in the figures) for air to flow through, and a bottom plate 15 between which plates the blades 13 are fastened.

The blades 13 are positioned symmetrically about the rotation axis of the fan wheel 12 and extend from an inner radius n, which may be equal to or greater than zero as measured from the rotation axis of the wheel, to an outer radius r₂, which may equal the radius of the fan wheel 12. The blades 13 may be backward-curved or backward-inclined. Similarly, the blades 13 may be forward-curved or forward-inclined. Alternatively, the blades 13 may extend straight along the radial direction of the fan wheel 12.

The fan unit 1 also comprises a motor 16 which may be electrical. The motor 16 can be arranged inside the housing 2, outside the housing 2 or partly inside and partly outside the housing 2. For example, the motor can be mounted inside the second space 7b. The motor 16 may be integrated with the fan wheel 12.

Figure 4 shows a fan unit 1 with the second space 7b presenting a first portion 7b' and a second portion 7b" which are juxtaposed along the axial direction and between which air can flow. The second portion 7b" is connected to the exterior via the second outlet 9b. The partition wall 6 has a first portion 6a, which is substantially parallel to the top wall 4 and the bottom wall 3, and a second portion 6b which connects to the top wall 4. The second portion 6b may be substantially parallel to the axial direction or inclined with respect to the axial direction. A lower boundary of the second portion 7b", i.e. the boundary that separates the second portion 7b" from the first portion 7b', may be defined by a virtual, straight extension of the first portion 6a. An upper boundary of the second portion 7b" may be defined by a portion of the top wall 4 having a length l which is larger than the thickness of the side wall 5b and typically smaller than . The sum of l₄ and is approximately equal to 1 ₁.

During operation, the motor 16 rotates the fan wheel 12. The rotation of the fan wheel 12 provides a suction force which causes an air flow F, to enter the first space 7a through the first inlet 8a along a direction which is

substantially perpendicular to the axial direction. The suction force provided by the rotating fan wheel 12 subsequently draws the air through the opening 10 and to the fan wheel 12. The rotating fan wheel 12 then pushes the air outwards in the radial direction of the fan wheel 12, thereby creating an air flow F₀ out from the second space 7b through the second outlet 9b. If the second space 7b" is arranged as in figure 4, the air is to a lesser extent pushed through the second outlet 9b by the blades 13 of the rotating fan wheel 12. Rather, a pressure difference between the second portion 7b" of the second space 7b and the exterior of the housing 2 causes air to flow out through the second outlet 9b. The direction of the air flow F₀ can be

substantially perpendicular to the axial direction and substantially parallel to the air flow F,. Alternatively, the first inlet 8a and the second outlet 9b are arranged so that the directions of the air flows F, and F₀ are substantially perpendicular to each other as well as to the axial direction.

In Figures 5-7b, there is disclosed another embodiment of the fan unit, wherein the second space 7b is designed substantially as the one in the embodiment disclosed in Figures 1 -2, but wherein the first space 7a' has been given a different design. The second space has a gradually diminishing flow cross section, as seen in a direction perpendicular to a flow direction Fi at the inlet portion 1 1 and in direction from the inlet portion 1 1 to a center of the opening 10.

As seen in a plane parallel with the flow direction Fi, and with the footprint of the fan unit 1 ', the first space 7a' has a substantially triangular cross section (i.e. the first space has a substantially triangular footprint), with the base of the triangle at the inlet portion 1 1 and with the tip of the triangle being truncated and optionally rounded. A height of the first space 7a', as seen in a direction perpendicular to the footprint, may be constant over most of the space, preferably over at least 70 % of the space or over 80 % of the space or over 90 % of the space.

The rounding of the footprint of the first space 7a' may approximate the edge of the opening 10.

By reducing the size of the first space 7a' footprint such that the first space has a smaller footprint than the second space 7b, the second space 7b may extend further in the outlet flow direction Fo than the first space 7a'. This may facilitate the mounting of a channel element (not shown) to which the flow Fo out from the fan unit may be guided, for example by allowing the outlet part of the fan unit to be inserted into the channel element. To this end, at least some, preferably all, of the walls defining the outlet opening may be provided with a respective flange 22, which may be formed by a small outward fold or ridge formed at the edge portion of the sheet forming the respective wall. Such a fold or ridge may facilitate the attachment of the channel element.

Claims

1 . A fan unit (1 ) comprising:

a housing (2) enclosing a first space (7a), which has a first inlet (8a) and a first outlet (9a), and a second space (7b), which has a second inlet (8b) and a second outlet (9b);

a fan wheel (12) arranged inside the second space (7b); and

a motor (16) for driving the fan wheel (12),

wherein the first outlet (9a) and the second inlet (8b) provide a passage for air to flow between the first space (7a) and the second space (7b),

wherein the first inlet (8a) provides a passage for air to flow into the first space (7a) along a first direction which is substantially perpendicular to a rotation axis of the fan wheel (12), and

wherein the second outlet (9b) provides a passage for air to flow out from the second space (7b) along a second direction which is substantially perpendicular to the rotation axis of the fan wheel (12).

2. A fan unit (1 ) according to claim 1 , wherein the second outlet (9b) is arranged at a first distance from a first major wall (4) of the housing (2) and a second distance from a second major wall (3) of the housing (2).

3. A fan unit (1 ) according to claim 1 or 2, wherein the second space (7b) has a first portion (7b') and a second portion (7b") which are juxtaposed along a direction parallel to the rotation axis of the fan wheel (12).

4. A fan unit (1 ) according to claim 1 or 2, wherein at least one of the first space (7a) and the second space (7b) is formed substantially as a rectangular parallelepiped having an opening in one side, which opening forms the first inlet (8a) or the second outlet (9b), respectively.

5. A fan unit (1 ) according to any of the preceding claims, wherein a height of the flow cross section of the second space (7b) is equal to or greater than a height of the cross section of the first space (7a).

6. A fan unit (1 ) according to any of the preceding claims, wherein the first space (7a) presents an inlet portion (1 1 ) which tapers in flow cross section.

7. A fan unit (1 ) according to any of the preceding claims, wherein the first direction and the second direction are substantially parallel.

8. A fan unit (1 ) according to claim 1 to 8, wherein the first direction and the second direction are substantially perpendicular.

9. A fan unit (1 ) according to any of the preceding claims, wherein the fan wheel (12) is a centrifugal fan wheel.

10. A fan unit (1 ) according to any of the preceding claims, wherein the fan wheel (1 ) comprises backward-curved blades (13) or backward inclined blades (13).

1 1 . A fan unit (1 ) according to any of the preceding claims, wherein the motor (16) is mounted inside the second space (7b).

12. A fan unit (1 ) according any of claims 1 to 10, wherein the motor

(16) is mounted outside the housing.

13. A fan (1 ) unit according to any of the preceding claims, wherein the motor (16) is an electrical motor.

14. The fan (1 ) unit as claimed in any of the preceding claims, wherein the fan unit (1 ) consists essentially of the housing (2), the fan wheel (12) and the motor (16).

15. The fan unit as claimed in any one of the preceding claims, wherein the second space (7b) extends further than the first space (7a'), as seen in a direction of the flow (Fo) out from the second space (7b).

16. The fan unit as claimed in any one of the preceding claims, wherein a wall edge portion at the second outlet presents a protrusion (22) which extends away from the direction of the flow (Fo) out from the second space (7b).