Radial fan for an extractor hood

Description

[0001] The invention relates to a radial fan for a cooker hood with a spiral fan housing.

[0002] For extractor hoods and range hoods, drum rotor fans and backward-curved radial fans are primarily used in the current state of the art. However, these require a comparatively large axial installation space.

[0003] The invention is therefore based on the objective of providing an axially compact blower for use in a cooker hood or extractor fan, which is improved in terms of flow technology in such a way that the noise generation is minimized.

[0004] This problem is solved by the combination of features according to claim 1.

[0005] According to the invention, a radial fan designed for a range hood is proposed, comprising a spiral fan housing with an axial intake opening and a radial outlet opening, as well as a radial impeller arranged in the fan housing with impeller blades arranged in a blade ring. The radial impeller has an axial intake associated with the axial intake opening and a radial outlet at the radial end of the impeller blades. The intake defines an intake cross-sectional area A in its axial plane, and the outlet defines a circumferential surface area M, wherein the ratio of the intake cross-sectional area to the surface area is specified such that: 0.75 ≤ A / M ≤ 1.0, more preferably 0.8 ≤ A / M ≤ 0.9.

[0006] The specific geometric selection and determination of the ratio between the intake cross-sectional area A and the circumferential surface area M of the outlet results in minimal deceleration of the drawn-in flow within the radial impeller from its intake, through the flow channels between the impeller blades, to the outlet, thus significantly improving its acoustic behavior. This specific ratio ensures a very uniform velocity profile of the flow at the outlet of the radial impeller. Furthermore, noise-generating flow separation in the blade channel between the individual impeller blades is prevented. When used in spiral-shaped fan housings, the ratio according to the invention can also contribute to improving the interaction between the radial impeller and the spiral tongue of the fan housing, thereby reducing the rotational tones generated at the spiral tongue.

[0007] For improved efficiency, the radial blower preferably features backward-curved impeller blades, meaning the impeller blades extend in an arc opposite to the direction of rotation. The specific ratio of the intake cross-sectional area to the outer surface area allows the use of backward-curved impeller blades, although this is actually disadvantageous with regard to the generation of rotational noise.

[0008] In a fluid-technically advantageous embodiment according to the invention, the radial blower is designed such that the spiral blower housing has a circumferentially oriented outlet opening with a maximum outlet opening cross-sectional area S, wherein a ratio of an intake opening cross-sectional area Q of the intake opening of the blower housing to the outlet opening cross-sectional area S is specified such that: 1.2 ≤ Q / S ≤ 1.7. More preferably, 1.4 ≤ Q / S ≤ 1.5. This specific geometric adaptation improves the flow characteristics and helps to reduce the generation of rotational noise.

[0009] Another advantageous aspect of the radial blower is characterized by a diameter ratio of a maximum diameter AD of the intake of the radial impeller to a maximum outlet diameter DD at the discharge of the radial impeller, such that: 0.65 ≤ AD / DD ≤ 0.75, more preferably 0.68 ≤ AD / DD ≤ 0.72. It was found that the specifically selected ratio contributes particularly advantageously to solving the problem.

[0010] Furthermore, the problem is solved even better by a radial blower in which an axial outlet width AB at the discharge of the radial impeller is defined in relation to the maximum discharge diameter DD at the discharge of the radial impeller such that: 0.1≤AB / DD≤0.15, preferably 0 , 12 ≤ AB / DD ≤ 0,13 .

[0011] Furthermore, in a flow-optimized embodiment of the radial blower, it is provided that the spiral blower housing has an axial height H and a mean rectangular dimension B / L of its outer contour, wherein a ratio of the axial height H to the mean rectangular dimension B / L is specified such that 0.15 ≤ H / (B / L) 1 / 2 < ≤ 0.25, more preferably 0 , 17 ≤ H / B / L 1 / 2 ≤ 0,2 .

[0012] The radial blower is preferably designed such that the radial impeller has a cover plate that determines the intake and overextends the impeller blades at least in sections.

[0013] An advantageous embodiment provides that the cover plate has an axial plate height DS and the intake opening of the blower housing has an axial cylinder section with an axial cylinder height DZ, wherein a ratio of the difference between the axial plate height DS and the cylinder height DZ to the maximum outlet diameter DD at the discharge of the radial impeller is specified such that: 0.05≤(DS-DZ) / DD≤0.07, more preferably 0.055≤(DS-DZ) / DD≤0.065.

[0014] The outlet opening of the spiral-shaped blower housing preferably has a rectangular cross-section with, in particular, rounded corners.

[0015] Furthermore, the radial blower is preferably characterized in that the spiral blower housing forms a pressure chamber that increases in the circumferential direction over more than 180°, and in particular more than 270°. Preferably, the pressure chamber increases radially to form the spiral shape from the spiral tongue to the outlet opening. An increase in the pressure chamber in the axial direction can also be provided. Preferably, however, the axial height of the spiral blower housing is constant.

[0016] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 a perspective view of a radial fan; Fig. 2 the radial fan made of Figure 1 in side view; Fig. 3 the radial blower made of Figure 1in the axial top view; Fig. 2 the radial fan made of Figure 1 in a sectional view.

[0017] The Figure 1-4 The figures show an exemplary embodiment of the radial fan 1 designed for a cooker hood with the advantageous geometric conditions.

[0018] The radial blower 1 comprises the spiral blower housing 2 with the axial intake opening 3 and the outlet opening 4 formed at the end of the spiral. The blower housing 2 is formed from two axial parts. The motor 20, with a motor diameter MD, is positioned in the intake area of ​​the blower housing 2, along with the radial impeller 5, which is driven by the motor 20. The radial impeller 5 comprises a base disk 9 and a cover disk 12 with a plurality of backward-curved impeller blades 6 arranged in a blade ring between them. On the axial side corresponding to the intake opening 3, the radial impeller 5 defines the axial intake 7, and on the radial outer edge or outer shell, it defines the radial discharge 8 at the radial end of the impeller blades 6. The intake opening 3 is formed on an axially recessed inlet nozzle of the blower housing 2.

[0019] The intake 7 of the radial impeller 5 defines its intake cross-sectional area A in the axial plane at the inlet to the radial impeller 5. In the illustrated embodiment, this area is determined by the intake diameter AD as A = π·(AD / 2) ≤ 2. The outlet 8 defines the circumferential surface area M as a cylindrical surface area, which is calculated from the maximum outlet diameter DD at the outlet 8 and the axial outlet width AB of the radial impeller 5 as M = AB·π·DD. The ratio of the intake cross-sectional area A to the surface area M is 0.85 in the illustrated embodiment.

[0020] Referring to Figure 3 The blower housing 2, in its axial top view, has a maximum length L and a maximum width B. The maximum axial height H is in Figure 2The ratio H / (B / L) 1 / 2< of the axial height H to the mean rectangular dimension B / L is 0.18 in the embodiment shown. The spiral of the blower housing 2 increases exclusively in the radial direction starting from the spiral tongue 44 and over all four quadrants, i.e. over more than 270°.

[0021] Further referring to Figure 2 The circumferentially oriented outlet opening 4 of the spiral blower housing 2 is shown from the outlet side and has a width X and a height Y, which determine the maximum outlet opening cross-sectional area S = X·Y minus the rounded corners. The outlet opening cross-sectional area S is set in relation to the intake opening cross-sectional area Q of the intake opening 3 of the blower housing 2, where the intake opening cross-sectional area Q is determined by Q = π·(QD / 2) 2< , as shown in the Figure 1 and 4shown. This Q / S ratio is 1.4 in the illustrated embodiment. The diameter ratio AD / DD of the maximum diameter AD of the intake 7 of the radial impeller 5 to the maximum outlet diameter DD at the exhaust 8 of the radial impeller 5 is 0.7.

[0022] Furthermore, the axial outlet width AB at the outlet 8 of the radial impeller 5 is set to the value AB / DD=0.12 in relation to the maximum outlet diameter DD at the outlet 8 of the radial impeller 5.

[0023] Referring to Figure 4It is shown that the cover plate 12 of the radial impeller 5 has an axial disc height DS. The size of this height is related to the intake opening 3 of the blower housing 2, which defines the axial cylinder section with an axial cylinder height DZ. The ratio of the difference between the axial disc height DS and the cylinder height DZ to the maximum outlet diameter DD at the discharge 8 of the radial impeller 5 is set such that (DS-DZ) / DD=0.6.

Claims

1. A radial fan (1) for a fume extractor, with a spiral-shaped fan housing (2) with an axial intake opening (3) and an outlet opening (4), a radial impeller (5) arranged in the fan housing (2) with impeller blades (6) arranged in a blade ring, wherein the radial impeller (5) has an axial intake (7) associated with the axial intake opening (3) and a radial discharge (8) at the radial end of the impeller blades (6), wherein the intake (7) in its axial plane determines an intake cross-sectional area A and the discharge (8) determines a circumferential mantle area M, and characterised in that a ratio of the intake cross-sectional area A to the mantle area M is set so that: 0.75≤A / M≤1.0 and that the outlet opening (4) of the spiral-shaped fan housing (2) facing in a circumferential direction has a maximum outlet opening cross-sectional area S, wherein a ratio of an intake opening cross-sectional area Q of the intake opening (3) of the fan housing (2) to the outlet opening cross-sectional area S is set so that: 1.2 ≤ Q / S ≤ 1.7 .

2. The radial fan according to claim 1, characterised in that 0.8≤A / M≤0.9.

3. The radial fan according to claim 1 or 2, characterised in that the impeller blades (6) are embodied curved backwards.

4. The radial fan according to any one of the preceding claims, characterised in that 1.4≤Q / S≤1.5.

5. The radial fan according to any one of the preceding claims, characterised in that a diameter ratio of a maximum diameter AD of the intake (7) of the radial impeller (5) to a maximum outlet diameter DD at the discharge (8) of the radial impeller (5) is set so that: 0.65≤AD / DD≤0.75.

6. The radial fan according to claim 5, characterised in that 0.68≤AD / DD≤0.72.

7. The radial fan according to any one of the preceding claims, characterised in that an axial outlet width AB at the discharge (8) of the radial impeller (5) compared to a / the maximum outlet diameter DD at the discharge (8) of the radial impeller (5) is set so that: 0.1≤AB / DD≤0.15.

8. The radial fan according to claim 7, characterised in that 0.12≤AB / DD≤0.13.

9. The radial fan according to any one of the preceding claims, characterised in that the spiral-shaped fan housing (2) has an axial height H and an average rectangular dimension B / L of its exterior contour, wherein a ratio of the axial height H to the average rectangular dimension B / L is set so that 0.15≤H / (B / L)1 / 2≤0.25.

10. The radial fan according to claim 9, characterised in that 0.17≤H / (B / L)1 / 2≤0.2.

11. The radial fan according to any one of the preceding claims, characterised in that the radial impeller (5) has a cover plate determining the intake (7), which stretches at least in part over the impeller blades (6).

12. The radial fan according to the preceding claim, characterised in that the cover plate has an axial plate height DS and the intake opening (3) of the fan housing (2) has an axial cylinder portion with an axial cylinder height DZ, wherein a ratio of the difference of the axial plate height DS and the cylinder height DZ to a / the maximum outlet diameter DD at the discharge (8) of the radial impeller (5) is set so that: 0.05≤(DS-DZ) / DD≤0.07, in particular 0.055≤(DS-DZ) / DD≤0.065.

13. The radial fan according to any one of the preceding claims, characterised in that the outlet opening of the spiral-shaped fan housing (2) has a rectangular cross-section with in particular rounded corners.

14. The radial fan according to any one of the preceding claims, characterised in that the spiral-shaped fan housing (2) forms a pressure chamber increasing in size in the circumferential direction by more than 180°, in particular more than 270°.