EP2738394A1 - Housing for a radial blowe and radial blower - Google Patents

Abstract

The housing (101) has an inner wall portion (127) on an air inlet side (118) of a radial fan impeller (103), where the radial fan impeller is rotatably mounted about an axis of rotation in the housing. The inner wall portion is inclined with respect to a plane (129) of the radial fan impeller that is perpendicular to the axis of rotation. The inner wall portion is inclined such that it axially limits an inner air space (131) of the housing.

Description

The present invention is in the field of radial blowers for household appliances, and particularly laundry treating appliances, and relates to a housing for a radial fan having an inner wall portion on an air inlet side of a radial fan wheel rotatably supported in the housing about an axis of rotation facing the radial fan wheel.

Such a housing and a radial fan are out of the EP 1 637 643 A2 known, which describes a clothes dryer with a fan having a fan housing. The blower housing serves for air flow guidance around a radial blower wheel (impeller) mounted rotatably in the housing, which draws in incoming air in the central wheel area and conveys it out of the housing out of a radial outflow opening.

From the EP 0 702 105 B1 is a household appliance known in which a radial impeller is rotatably mounted in a spiral housing and the air to be supplied flows axially. The blower housing can be used in particular in a blower for a tumble dryer.

The EP 1 990 465 A1 relates to an air duct of a tumble dryer, which supplies air to a radial fan, wherein a displacement body is arranged as a noise-reducing measure in an air-stromumlenkenden section of the air duct.

Also with regard to the noise beats the DE 199 18 085 A1 a blower for conveying process air in a tumble dryer with a spiral housing, in which a rotor is mounted with circumferentially distributed blades and a concentric suction port. The suction opening is surrounded by a cover disc which is connected on one side to the blades, wherein the side of each blade facing the cover disk extends in a curved manner in a specific way for improving the efficiency and reducing noise.

Nevertheless, in previously known blowers, the efficiency of the blower is not always satisfactory, whereby an increased total energy demand or an increased power requirement is required. This can affect customer satisfaction.

It is an object of the present invention to provide a housing for a radial fan and a radial fan (also referred to as a centrifugal fan, centrifugal fan or drum rotor blower) which has an increased efficiency and thereby enables a device energy efficiency increase while achieving a noise reduction.

This object is solved by the subject matter of the independent claim. Further details, aspects, advantages and preferred developments of the invention are the subject of the following description, the other claims and the drawings and their description.

Accordingly, it is provided according to the invention in a housing of the type mentioned that the inner wall portion is inclined relative to a plane of the radial impeller, which is perpendicular to the axis of rotation.

Characterized in that the inner wall portion which limits in particular a part of an inner air space of the radial fan housing, inclined or tilted to the plane perpendicular to the axis of rotation of the Radialgebläserades arranged or oriented, an optimized flow of the conveyed air is realized , whereby an overall energy efficiency increase and a noise reduction can be achieved. This can have a positive effect on customer satisfaction, especially in times of increasing energy costs and growing awareness of resources. In particular, the inclined inner wall area (hereinafter also referred to as a spiral floor, in particular inclined spiral floor) can serve as a link between confined space and optimized designed airways.

In a conventional radial blower, a full potential exploitation is sometimes limited by a tight installation space directly around the blower, so that the highest requirements in terms of performance, energy efficiency, durability and noise emission can not always be met.

The inclined inner wall region can in particular serve as an optimized flow guide for air, which enters the fan at the air inlet side and is accelerated radially outwards by the radial fan wheel, in order then to leave the radial fan at an air outlet opening. It can come within the interior of the radial fan housing to a so-called secondary recirculation in the Radialgebläserad (also referred to as impeller or drum rotor), which can be reduced by the inclined arranged inner wall area. Due to this orientation or arrangement of the inner wall region, interfering vortex generators ("bottleneck") and disturbing three-dimensionally directed flow filaments close to the housing can be reduced or eliminated altogether. In addition to a reduction of a secondary recirculation of the inclined inner wall region arranged can also lead to an optimized flow guidance of the exiting air, which leaves the radial fan housing through the air outlet opening.

According to a preferred embodiment of the present invention, the inner wall portion is inclined so as to axially restrict an inner air space of the housing so that the axial extent of the air space in the area (particularly along a circumferential direction perpendicular to the axial direction and perpendicular to the radial direction) of an air outlet opening is minimum is. The "axial direction" is understood as a direction parallel to the axis of rotation of the radial impeller, the radial direction is to be understood as a direction perpendicular to the axial direction. Thus, since the axial extent of the air space is smaller at the circumferential position area where there is an air outlet opening than at other circumferential positions, improved guidance of the air to the air outlet opening is achieved, whereby higher energy efficiency and noise reduction and power increase can be achieved ,

The radial impeller may rotate about the axis of rotation and includes air vanes for accelerating the air in the radial direction. The air outlet opening can be located in particular in a peripheral boundary wall of the radial fan housing.

According to a further preferred embodiment of the present invention, the inner wall area forms (also) part of a transition to the air outlet opening. The inner wall region preferably has an extension in the circumferential position region on, on which an air outlet opening is located. The preferred funnel-shaped extension of the inner wall region may comprise a structure which extends in the tangential direction (perpendicular to the axial direction and perpendicular to the radial direction) and expands or expands in an extension perpendicular to the tangential direction (along the tangential direction) enlarged. The funnel-shaped enlargement may in particular be trumpet-shaped or cone-shaped. Thus, the inner wall area may extend tangentially beyond an air outlet area of the radial fan in order to advantageously guide the air emerging from the radial fan to a subsequent air line or a guide system and thus to reduce the flow resistance.

According to a further preferred embodiment of the present invention, the inner wall area is at least partially planar. By a (partially) planar or planar formation of the inner wall region, an advantageous flow of the air accelerated by the radial impeller along the inner wall region can be ensured while reducing the flow resistance. Also, the inner wall area, which according to a particularly preferred embodiment of the invention can be designed, in particular, as an insert for an existing fan housing, can also be simple to manufacture.

According to a further preferred embodiment of the present invention, the inner wall region at least partially has a ring shape with an approximately circular free space, through which an air inlet is made possible. The ring shape can enclose an air inlet region of the radial fan. In particular, (for retrofitting) the inner wall portion can be used in conventional radial blowers, which allow air to enter in the axial direction, ie along or parallel to the axis of rotation of the radial impeller, and which often allow an axially directed air flow into the fan through a circular opening cross section. Due to the inclined orientation of the inner wall region, the ring shape and / or the free space can deviate from an exact circular shape and instead have in particular an elliptical shape. In particular, the ring shape and / or the clearance, when projected along the axial direction, can give a circular shape.

According to a preferred embodiment of the invention, the inner wall portion in a peripheral portion of the ring has a recess or bulge to avoid a collision with the Radialgebläserad. The bulge of the inner wall region can - seen from the interior of the radial fan housing - have a curved or curved, in particular concave shape. The bulge may extend over a portion of the circumference, e.g. over an angular range of about 50 ° to 120 °. The bulge may taper at the boundaries of the portion and / or increase in radial extent from a peripheral boundary to a maximum, and then decrease in their radial extent again to another peripheral boundary. In this way, obstruction of the inner wall region can also be achieved in cramped conditions in that the bulge in the assembled state of the radial fan housing or the radial fan provides an increased clearance for receiving and rotating the radial fan wheel due to the bulge.

According to a further preferred embodiment of the invention, the protrusion is limited in projection by a crescent-shaped edge. The crescent-shaped edge may in particular comprise a radially inner edge and a radially outer edge, between which the inner wall region is located axially further downstream (seen in the direction of an air inlet), ie. has a bulge, as in areas of the inner wall portion outside the bulge. Thus, a radial fan wheel space can be made available within the radial fan housing in an advantageous manner.

According to a further preferred embodiment of the invention, the radial fan housing on an outer annular, in particular (viewed in the direction of inflowing air) convex wall portion on the air inlet side, which tapers in the direction of the air inlet direction from a first axial position to a second axial position in its radial extent wherein the inner wall portion is inclined so as to extend in a space region bounded axially by the first axial position, and more particularly at least approximately by the second axial position. The outer annular wall portion may restrict an air inlet area for entry of air in the axial direction. The outer wall portion may constitute or form part of an outer surface of the radial fan housing. The second axial position may be seen in the direction of the incoming air downstream of the first axial position be arranged. Thus, the inner wall portion can be used in a conventional radial fan case because it is inclined so as to be compatible with a conventional air inlet wall portion. In particular, the outer annular wall portion may be funnel-shaped to allow a streamlined air inlet.

According to a particularly preferred embodiment of the present invention, the inner wall portion is formed by a separate part and formed fastened to at least one further wall portion, in particular in the circumferential direction, of the housing. As a result, the inner wall area can also be retrofitted in a (conventional) radial blower housing, so as to retrofit in a simple manner a conventional radial blower housing to increase energy efficiency and performance and to reduce noise pollution.

The radial fan housing may have a spiral shape, wherein the inner wall portion has a shape of a projection of a spiral shape. As already mentioned, the spiral shape (which in projection may have a similarity to a schematized post horn) can allow a favorable flow of the air, in particular in the exit region. The inner wall portion may allow an improvement of the flow characteristic both in the part of the inner space located near the impeller blades of the radial impeller and in the space portions adjacent to the air exhaust opening, thus also positively influencing the flow of the air further downstream be able to have located components.

According to a preferred embodiment of the invention, the radial fan housing further comprises a particular connected to the air outlet opening air outlet duct, which at a radial position has a minimum inner dimension in the axial direction (of the housing), wherein the inner wall portion is inclined such that an extension of the inclined wall portion axially within a range that is at most 1.5 times to 2.5 times the minimum inner dimension of the air exhaust duct. The air outlet duct may in fact have a narrowest point (with respect to an internal extent) owing to a limited installation space, which presents an increased resistance to an air flow. Due to the inclination of the inner wall region, however, air leakage in an optimized manner be directed to this narrowed point of the air outlet conduit, so as to achieve a favorable outflow, which can reduce noise, performance-enhancing and energy consumption reducing effect.

The present invention also provides a domestic appliance, in particular a dryer or washer-dryer, with a radial blower housing or according to one of the embodiments described above.

Features which have been described, referred to or explained individually or in any combination in connection with a radial blower housing may also be applicable individually or in any combination with or for a radial blower.

Figur 1

schematisch im Querschnitt ein Radialgebläse mit einem Radialgebläsegehäuse,

Figuren 2A, 2B und 2C

schematisch im Querschnitt Schritte zum Zusammensetzen eines Radialgebläsegehäuses und

Figur 3

eine teilweise weggebrochene perspektivische Ansicht eines Radialgebläsegehäuses.

Embodiments of the invention will now be described with reference to the drawing, the invention not being limited to the illustrated or described embodiments. Show it:

FIG. 1

schematically in cross-section a radial fan with a radial fan housing,

FIGS. 2A, 2B and 2C

schematically in cross section steps for assembling a radial fan housing and

FIG. 3

a partially broken away perspective view of a radial fan housing.

FIG. 1 shows a schematic cross-sectional view of a radial fan 100 with a radial fan housing 101. The radial fan 100 has a radial impeller 103, which can rotate driven by a shaft 105 and having paddle wheels 107. These are configured to suck air 108 along an axial direction 109 and accelerate the air 108 in a radial direction 111. In a peripheral region 112, which in the sectional plane of the Fig. 1 is located, the thus accelerated air 108 passes through an air outlet opening 113 and an air outlet conduit 115 out of the housing 101. The air 108 then passes to its further (not shown) use, eg for drying laundry, in a laundry drum.

The housing 101 has an outer annular wall region 117, which lies on the air inlet side or the air inlet region 118 of the housing 101. The wall portion 117 extends from a first axial position 119 to a second axial position 121 and tapers from a first radial extent 123 to a second radial extent 125. Because of this funnel-shaped shape or taper of the cross-section of the free air inlet area 118 is a flow-optimized inflow of air along the axial direction 109 allows.

Also disposed on the air inlet side 118 of the radial fan housing 101 is an inner wall portion 127 (fan bottom, in particular fan intermediate bottom) (the dotted section lies behind the outer wall 117), which is opposite to a plane 129 which is perpendicular to the axis of rotation 105 of the radial fan 103, is inclined by an angle α, which is particularly preferably between 5 ° and 30 °. By means of the inner wall portion 127, which is not present in the air inlet portion 118, but is present only in a radial region between the first radial extension (position) 123 and the second radial extension (position) 125, an inner air space 131 of the radial fan housing 101 axially limited, depending on the circumferential position between the first axial position 119 and a third axial position 133 and between the second axial position 121 and the third axial position 133. In this case, a closer axial boundary between the second axial position 121 and the third axial position 133 at a circumferential position (or a peripheral region) where the outlet opening 113 is located.

The air outlet duct 115 is connected to the air outlet opening 113 and has a minimum internal dimension 137 in the axial direction measured at a radial position 135. The inner wall area 127 is inclined at an angle α relative to the plane 129 such that an imaginary extension of the inclined wall area towards the radial position 135 (intersection point 140) is within a range which is at most about 1.5 times to 2.5 times the minimum inner dimension 137 of the air outlet conduit 115. The point of intersection 140 has an axial distance, which is between 1.5 times and 2.5 times half the minimum inner dimension 137 of the air outlet conduit 115, from the axial center 138 of the air outlet duct 115 at the radial position 135.

The inner wall region 127 has, close to the blade wheels 107 of the radial fan wheel 103, in particular towards the outlet opening 113, an outward bulge 139 in order to avoid a collision with the radial fan wheel 103 or its blades 107.

The FIGS. 2A, 2B and 2C show steps of a manufacturing method for manufacturing a radial blower housing 201 according to an embodiment of the present invention, wherein the view in the axial direction 209 (ie with respect to Fig. 1 rotated by 90 °) takes place. FIG. 2A illustrates, seen from the inside, the outer wall portion 217 of the spiral blower housing having an air inlet area 218 and a funnel-shaped extension at the exit opening 213. A circular clearance (opening) 241 is provided for entry of air along the axial direction 209. FIG. 2B illustrates the inner wall portion 227, which has an extension 228 in the peripheral region 212 in which the air outlet opening 213 is located. The inner wall portion 227 is partially planar and has a nearly circular ring shape, but with a bulge 239, which is radially bounded by a respective crescent-shaped edge 243, 245 inside and outside. Figure 2C shows the state in which the inner wall portion 227, which in FIG. 2B is separately illustrated, and the outer wall portion 217 (FIG. FIG. 2A ) (or a conventional radial blower housing) were assembled. As a result, an improvement in the performance characteristics of a conventional radial fan housing is possible.

FIG. 3 illustrates in a partially broken away perspective view a radial fan housing 301 according to an embodiment of the present invention. The axial direction is designated by 309 and the radial direction by 311. The outer wall portion 317 circularly defines an air inlet portion 318 which coincides with a clearance 341 recessed from the inner wall portion 327. The inner wall portion 327 has a bulge 339, which is bounded by the crescent-shaped edges 343, 345. The inner wall portion 327 is inclined relative to a plane 329 perpendicular to a rotation axis (parallel to the direction 309) by the angle α. In an exit region 313, accelerated air can escape through an unillustrated radial impeller.

LIST OF REFERENCE NUMBERS

α

angle

100

centrifugal blower

101

Radial blower housing

103

radial impeller

105

wave

107

paddle wheels

108

air

109

axial direction

111

radial direction

112

peripheral region

113

Air outlet opening

115

Air outlet pipe

117

outer wall area

118

Air inlet area

119

axial position

121

second axial position

123

first radial extent

125

second radial expansion

127

inner wall area

129

level

131

inner airspace

133

third axial position

135

radial position

137

internal expansion

138

Focus

139

bulge

140

intersection

201

Radial blower housing

209

axial direction

212

peripheral region

213

outlet opening

217

outer wall area

218

Air inlet area

227

inner wall area

228

extension

239

bulge

241

Free space (opening)

243

edge

245

edge

301

Radial blower housing

309

axial direction

311

radial direction

313

exit area

317

outer wall area

318

Air inlet area

327

inner wall area

329

level

339

bulge

341

free space

343

edge

345

edge

Claims (11)

Housing for a radial fan with
an inner wall portion (127, 227, 327) on an air inlet side (118, 218, 318) of a radial fan wheel (103) rotatably mounted in the housing about an axis of rotation (105) facing the radial fan wheel (103),
characterized in that
the inner wall area (127, 227, 327) is inclined relative to a plane (129, 329) of the radial fan wheel (103) that is perpendicular to the axis of rotation (105). Housing according to claim 1,
characterized in that
the inner wall portion (127, 227, 327) is inclined so as to limit an inner air space (131) of the housing (101) axially (119, 121, 133), so that the axial extent of the air space (131) in the region of an air outlet opening (113, 213) of the housing is minimal. Housing according to claim 1 or 2,
characterized in that
the inner wall portion (127, 227, 327) forms part of a transition to the air outlet opening (113, 313). Housing according to at least one of the preceding claims,
characterized in that
the inner wall region (127, 227, 327) is planar, at least in sections. Housing according to at least one of the preceding claims,
characterized in that
the inner wall portion (127, 227, 327) at least partially has a ring shape with an approximately circular free space (241), through which an air inlet is possible. Housing according to at least one of the preceding claims,
characterized in that
the inner wall portion in a peripheral portion of the ring shape has a bulge (139, 239, 339). Housing according to claim 6,
characterized in that
the bulge (139, 239, 339) of a crescent-shaped edge (243, 245, 343, 345) is limited. Housing according to at least one of the preceding claims,
characterized by an outer annular wall portion (117, 217, 317) on the air inlet side (118, 228, 318) which tapers radially in the direction of the air inlet direction from a first axial position (119) to a second axial position (121) the inner wall portion (127, 227, 327) is inclined so as to extend in a space portion bounded axially by the first axial position (119) and at least approximately by the second axial position (121). Housing according to at least one of the preceding claims,
characterized in that
the inner wall region (227) is formed by a separate part and is fastened to at least one further wall region of the housing. Housing according to at least one of the preceding claims,
characterized by an air exit duct (115) having a minimum internal extent (137) in the axial direction (109) of the housing at a radial position (135), the inner wall portion (127) being inclined such that extension of the sloped wall portion toward the Radial position (135) axially within a range which is 1.5 times to 2.5 times the minimum inner dimension (137) of the air outlet duct (115). Blower (100) for a domestic appliance, in particular for a dryer or washer-dryer, with a housing for a radial fan (101) according to one of the preceding claims.

Images