DE1628361A1 - Centrifugal blower - Google Patents

Description

I ¹ 18 -665 - West Germany ^v . . ■ "" ■ ■ "-

HS SBiial Ko. 524.50 t-: - '. '"■ - -

Pelartiary 2, 1966:. _r ; ',:;_v; .i

Haiiufacturing Co,;, Inc., Woodstock *:. Fe ^ - Xorfc,

. S.A *

Centrifugal fan

The invention relates to centrifugal fans, in particular " such as “They are often used in cases where minimal Weight, minimum size dimensions and optimal Capacity of the blower are required

The last two years, with the advent of miniaturization electronic ^ building blocks, has become an increasing Need for a small, powerful Etihl blower result. It is well known that electronic circuit arrangements, in particular semiconductor components, to temperatures

be kept within certain limits - so that they are flawless work. Through the spatial reduction of the individual components and through the use of microcircuit technology one is to a higher packing density, i.e. one larger number of electronic components within a given spatial volume. To such arrangements To keep them within the prescribed temperature limits, the components are usually flushed with cooling air. Often one likes to use centrifugal fans for this, as they are well suited to the cooling air against a considerable pressure gradient to overturn. Because of the high packing density, however, it is necessary to use fans which have an air flow with increased initial pressures promote in order to provide a sufficient flow of cooling air in the entire circulation. In addition, it is very desirable that the fan is as small and light as possible and has a compact shape.

As is well known, the performance of a centrifugal fan depends largely from the. Size of the rotating impeller. Around hence the overall size of the fan without sacrificing output to reduce, one must increase the efficiency of the fan. Such an increase in efficiency you also achieve that you can use a smaller motor to drive the impeller.

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It is therefore an object of the invention to provide a centrifugal fan with opposite "known blowers of this type create improved efficiency *;

The fan should be optimal for its size and weight Have delivery capacity. ;

The fan should be smaller in its dimensions its performance comparable to a well-known centrifugal blower.

These and other objects are achieved according to the invention in that the fan impeller is surrounded by a housing which has an air or flow chamber of generally elliptical cross-section increasing in the direction of the impeller rotation and of a spiral shape. The main axis of the cross-sectional ellipse runs parallel at the small-area end of the spiral and lower at the large-area blower outlet. right to the axis of rotation of the impeller. Because of this arrangement, you can optimal cross-sectional areas in the flow chamber for the; Preserve the volume occupied by the housing. The. Overall dimensions of the fan assembly are further reduced by partially screwing the jiotor into the fan housing. Thus, the Gesamtwirkungsgraxi is also _v increased by, dei? Motor is cooled by compressed air from the main air stream. Additional cooling is obtained in that there is a coupling between the rotor and the impeller

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a material of high thermal conductivity is provided, whereby. " the engine heat is diverted to the impeller, which acts as a heat sink. "

The following is based on the "accompanying drawings an embodiment of the invention described. Show it:

Figure 1 "is a partially sectioned front view a fan according to the invention;

Figure 2 is a partially cut-away side view of the Gebläses_nach Figure 1;

FIG. 3 is a view of the seen from the other side Blower according to Figure 1; '-

■■ Figure'4A -'4D sections of the fan housing, namely generally along lines A-A, B-B, C-G and D-D in Figure 3; and. ,; . ■

Figure 5 shows the performance diagram of a typical blower design according to the invention «

The capacity of a centrifugal fan is how mentioned, mainly proportional to the size of the iaufradös; The extent to which the radial and lateral or axial Dimensions of the impeller in the interest of the compactness of the Total can be reduced to baus ^^ is therefore by the required size of the impeller and the required Efficiency of the fan is limited. With conventional

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the overall radial dimension cannot be reduced in size without loss of efficiency or flow rate. According to the invention, on the other hand, the radial dimension of the fan is reduced by using a specially designed "fan housing with a chamber of elliptical cross-section. The weight and dimensions of the fan are further reduced by" using a smaller motor, which is increased by the achieved Cooling effect becomes possible. In addition, the size of the device can be reduced by the fact that; the motor is partially built into the housing. Therefore, the combined use of the called en measures, ie, small size, high power and low weight, th purpose of achieving, optimal own sheep helps beii that the present fan the tasks for which it is intended ^dissolves; * -

The fan shown in Figures 1 and 2 includes an impeller 10, which is driven by the motor 12, so that it in the housing 14 rotates. The housing 14, which is made of eolyester synthetic resin be made with low weight a spirally wound air chamber or flow chamber I ^ generally elliptical in cross-section. As can be seen in FIG. 1, the inner circumference is at 1 17 the crest open to the air required by the circumference of the impeller 10 to read * The impeller 10 sucks at Beiner ITm-

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rotation of air into an intake port or duct on the side of the housing 14 with an edge 16a, the contour of which is adapted to the suction flow, and the blades 10a set the axial suction flow into a centrifugal flow around that in the open inner part 17 of the spiral Chamber 15 exits.

As best seen in Figure 1, the sinuous Chamber 15 at the junction between the diffuser section 19 and the. winding part of the housing 14- a constriction or throat 18. The lower edge 18a (i.e., the edge in the direction of impeller rotation) of this throat runs at an angle to the impeller blades 10a. How to get in Figure 1 sees the edge 18a spanning or bridging two successive blades 10a, whereby the flutter and the pulsation noise are suppressed, which otherwise by the drainage of between successive Trapped air vanes 10a would be generated as the vanes pass the throat.

From the inlet end of the chamber 15 "immediately below the Throat 19 (FIG. 2), from the winding radius of the chamber 15 gradually increases in the direction of the impeller rotation. Simultaneously takes, as best seen in Figures 4A-4D, the ratio of dimension 20a to dimension 20b of the elliptical

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% cross section of the rammer * gradually closed, Ms at the outlet of the? Chamber for Diffüsorabsöhnitt i'9 this Jfeikältnl is greater than 1. That is to say, the axis of the elliptical cut parallel to the axis of the motor 12, which is the elliptical axis in the small-area parts of the ^ Wi; ridiaög Mldet Cf-Lgur M), gradually merges into the chain axis ώ toslaß of the chamber (iigur Λ and '4B), where the main axis runs in an isolated plane, including all points along the chamber 15, the cross-sectional area is so dimensioned that optimal air flow properties are obtained. As is readily apparent from the details, the aforementioned design provides a combination of optimal flow properties with minimal axial and radial; Dimensions.

In 3igur 1 the engine is ^: i% ;

demonstration of his I ^ gebeizlehuÄg zum (iebläse, shown. The Motor includes a stand 21 and a runner? 22 who through the bearings 24 and 25 mounted on the shaft 23 1st * according to the invention are the stator corrugations en 21a: unC! Belle des Muf ers 22 to the "air flow generated by the rotating impeller IO in the SeMuse 14: exposed to" the partial installation of the motor 12 in the housing 14 for two purposes " thereby the axial length of the fan Tiet ^ ächtl ^ and second, by deriving the iSTarms from the

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Dedications 21a and the runner 22 by the cooling effect of the circulating air requires the use of a smaller motor possible. The latter of course results in a further reduction the axial length, the fan arrangement and a reduction of the power requirement.

The impeller 10 is connected to the rotor 22 by a generally cylindrical rotor end ring and hub arrangement 27 made of aluminum or another suitable material high thermal conductivity connected. The hub 27 forms a Continuation of the rotor and has a considerable surface 27b in thermal contact with the metal parts of the Impeller 10. This training enables good heat transfer from the rotor 22 to the impeller 10, which acts as a heat sink because of the strong air flow passing through it.

A motor housing JO with a flange part 31 on its inner end supports the motor shaft 23 and encloses the outside or left end of the engine 12. The Flange 31 has, in its surface 33 near its outer circumference, a circumferential groove 32 which has a cylindrical extension 34 on Housing 14 receives. As a result, the housing 14 can slide be rotated relative to the motor housing 30. When the blower by attaching the motor housing 30 to an outer Bracket (not shown), for example by means of

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the holder and the threaded holes 36 at the bottom of the motor housing 30 screw bolts to be mounted so you can move the housing 14 relative to the outer bracket.-so twist that the required air flow in its direction can be changed over an angle of -360 ° »

The motor housing ■■ JG and the fan housing 14 can by means of an arrangement from that disclosed in the USAr patent application Serial Ιο. 524 540 by the same applicant dated February 2, 1966 (Inventor: William A. Seabury III) described type together be attached. This fixed spinning device consists, in short, from a number of clamping blocks 40 with an inclined surface 40a at one end, the longitudinal flat surfaces can be slid on an equal number of ribs 42 arranged radially on the motor housing 30. Each clamping block 40 is from one penetrating a slot 45 in the motor housing Clamping screw 44 detected. When the tensioning screws are tightened, the blocks 40 are pulled against the screw head, with them against the bevel of the hip 42 and the shoulder 34 rest so that the fan housing is attached to the motor housing. By loosening the You can loosen the two parts from each other without screws to take apart the jig.

The flange 31 on the motor housing 30 can also be a

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have axial extension 31a, so that a to the motor 12

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space running around / arises. This space, by which the overall radial dimension of the fan is not increased, can be used for the installation of electrical components, for example the starting capacitor 51 shown in the upper part of the space 50, switches, overload relays, etc. A suitable interference fit ring 52 can be provided to seal off the space 50.

The characteristics of the inventive blower can be seen from the performance graph of Figure 5 obtained with a blower that is less than 27.9 cm (11 inches) by 30.1 cm (12 inches) by 19.1 cm ( 7.3 inches) in depth and weighed 6.35 kg (14 pounds). As can be seen from the diagram, this fan can handle more than 8.4 m (300 cubic feet) per minute at a static pressure of 7.62 cm (3 inches) of water. The invention thus creates a centrifugal fan, the dimensions of the known fan with optimal size and weight

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is superior.

As mentioned, the entire unit can be screwed into the threaded holes 36 in the housing part 31a by means of screws • be attached to a holder or a wing. Man but the unit can also be attached to a plate or wall

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a suitable opening for the outlet end of the diffuser part 19, for what purpose the flange 48 of the Diffuser with holes 48a for suitable fasteners is provided .-- Although not shown, the exterior may or left end of the motor housing with (each hole for screwing in of fastening screws or the like. Be provided for mounting on a holder or a plate.

The embodiment described above can modify within the scope of the invention in several ways and shape it differently.

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Claims (8)

Claims fW centrifugal fan with one that holds the impeller Housing, characterized that the housing (14-) has a spirally wound flow chamber (15) of generally elliptical cross-section and with a inner, circumferential inlet and has an outlet for the air conveyed by the impeller, the ratio of the dimension of the minor axis to Dimension of the major axis of the elliptical cross-section progressively from one end of the small radius chamber in Direction to the chamber outlet increases. 2. Centrifugal fan according to claim 1, characterized marked that the larger axis on The inlet is generally parallel to the axis of the housing and, at the outlet, is generally perpendicular to the axis of the housing. 3. centrifugal fan according to claim 1 or 2, d a through marked that the inlet is on the circumference of the impeller and .the radius of the spiral winding of the chamber around its axis in the 10983 direction of the impeller increases. V 4. Centrifugal fan according to claim 3 »d a'd u r c h g e k e η η ζ e i ο h η e t that the cross-sectional area the chamber increases progressively with the increasing radius of the chamber curvature. , 5 · Centrifugal fan according to one of the preceding Claims, characterized in that that the motor (12) driving the impeller partially from Housing is enclosed in such a way that it adapts to the flow of air exposed to the inside of the impeller. 6. centrifugal fan according to claim 5 »in which the The rotor of the motor has a metallic core part, d a by g e ken η ζ ei c h net that the that Impeller with the rotor coupling device made of thermally conductive Material consists and the impeller as well as a considerable Touched part at one end of the core part of the rotor in order to dissipate the heat from the motor to the impeller. 7. Centrifugal fan according to claim 5, characterized by a part of the motor enclosing motor housing, which the motor is equiaxed 109034/0279 with the fan housing. 8. centrifugal blower according to claim 7 »thereby characterized in that .the motor housing contains means for attaching the fan to an external mount and slidably rotatable with respect to the fan housing is. · · 9 · Centrifugal fan according to one of the preceding claims, characterized in that the housing (14) has a diffuser section (19) at its outlet. 109834/0279 Le e rs e lie