GB2031114A

GB2031114A - Radial impellers for fans

Info

Publication number: GB2031114A
Application number: GB7920764A
Authority: GB
Original assignee: Luft und Kaeltetechnik VEB
Current assignee: Luft und Kaeltetechnik VEB
Priority date: 1978-07-10
Filing date: 1979-06-14
Publication date: 1980-04-16
Also published as: GB2031114B; DD137612A1; FR2431049A1; DD137612B1; CS220555B1; PL216912A1; DE2919323A1; PL121750B1

Abstract

A radial impeller for fans or blowers for conveying clean or dust- laden gases has blades (2) arranged continuously between impeller side plates (1) to form an impeller crown (3). The outside diameter of a central drive hub element (4) is smaller than the mean intake diameter (d1 m) of the blades. An elastic part (5) is provided between the impeller crown and the drive hub element. In use, adhesion of dust and wear by dust may give rise to a resulting imbalance causing radial displacements of the impeller crown. The elastic part (5) serves to transmit torque and to cushion the radial displacements so as to minimise transmission of such vibration to the bearings and drive shaft. <IMAGE>

Description

SPECIFICATION Radial impeller The invention relates to the conformation of impellers of radial construction for transporting pure and pulverous media. It is applicable to fans and blowers with predominantly twosided intake for medium and high pressures.

It is known to conform double-flow impellers of radial construction in such a way that the blades are fixed to the base disc on both sides. A cover disc may be arranged on each of the other sides of the blades. The outside diameter of the base disc is generally greater than the outlet diameter of the blades. The blades are fixed rigidly to the base and cover discs, the fixing is preferably effected by welding or riveting.

This solution has the disadvantage that it is highly material intensive and that adhesions or wear phenomena occur when pulverous gases are transported, more particularly in the region of the joints between blades and base disc. These lead to high dynamic loadings and/or to the damage of the impeller in that region. In the case of the adhesion of dust, considerable forces occur due to the resulting imbalances and are transmitted to the bearings and the drive shaft. These also cause inter alia serious flutter and considerable npise.

It is further known in heating fans to produce the blades and the blade carriers in one piece and to form the blades by bending the blade carrier to one or the other side alternately. This solution has the disadvantage that the number of possible blades is limited and that the blades are arranged alternately on the two sides. Moreover the possibility of blade curvature only exists in a narrow context. A continuous ring of the base disc, on which dust adhesions can occur, is still obtained at the hub.

Solutions are further known for the transport of strongly polluted media, in which the blades extend almost to the hub and occupy essentially a rectilinear radial position. In this case the impeller cover is absent. This solution has the disadvantage that the efficiency of this blower is very low. The radially extending supports for the blades permit only a very disturbed flow and therefore lead to increased adhesions.

It is the object of the invention to palliate the said disadvantages. More particularly, the wear of the impeller and the adhesion of the dust should be reduced as far as possible, and the material consumption and production time should be reduced.

The underlying aim of the invention is to attach the blades to the hub in such a way that the joint position is required substantially only for transmitting the torque and the effect of residual imbalances which occur is not, or only slightly, transferred to the driving torque.

This is achieved according to the invention in that the blades arranged continuously between the impeller covers form with the impeller covers an impeller crown which has no base disc. The necessary drive element is constructed smaller in its outside diameter than the mean inlet diameter of the blades.

The drive element is arranged centrally and between the latter and the impeller crown an elastic part is arranged to transmit the driving torque. The elastic part compensates the loading which acts due to the radial displacement of the impeller crown by particular deformation and reduces its transfer to the bearings.

The elastic part may be arranged between the impeller and the drive element or the wheel covers and the drive element. One possibility is that the elastic part is constituted by a part of the blades.

According to the invention the blades are fixed internally to a continuous ring. Between said continuous ring and the dive element there are present a number of elements which constitute the elastic part. It is further possible for the elements of the elastic part to be constructed as joints. The drive element which transmits the forces from the shaft to the impeller crown may be constructed as a plane or conical disc or a combination of both possibilities.

Reference is now made to the accompanying drawings in which: Figure 1 shows a double-flow radial empeller in section Figure 2 shows part of a radial empeller with continuous ring Figure 3 shows part of a radial empeller with joints Figure 4 shows double-flow radial empeller in section Figure 5shows a double-flow radial empeller in section with conical drive element.

The impeller of a radial fan comprises two impeller covers 1 which are mutually connected by the blades 2 jointly constitute the empeller crown 3. A drive element 4 is arranged centrally and its outside diameter is smaller than the mean intake diameter d, m of the blades 2. Between the empeller crown 3 and the drive element 4 there is present an elastic part 5 which is responsible for the transfer of the drive torque and reduces loading by the empeller crown on the drive system.

In Fig. 2 the blades 2 terminate inwardly at a ring 6. The connection to the drive element 4 is effected through elements 7 which in their totality constitute the elastic part 5. The number of the elements 7 differs from the number of the blades 2.

In Fig. 3 the elastic part 5 is constituted of elements 7 which are constructed as joints.

Fig. 4 shows the construction of the elastic part 5 as elements which are fixed to the empeller covers 1 and to the drive element 4.

Simultaneously the drive element 4 has been formed from a plane and a conical disc.

In Fig. 5 the elastic part 5 is a part of the blades 2 and the drive element 4 comprises two conical discs 4.

Claims

1. Radial impeller for fans and blowers for transporting pure and pulverous gases, preferably with two-sided intake, characterised in that blades (2) are executed continuously between the impeller covers (1) and constitute an impeller crown (3), the outside diameter of a central drive element (4) is made shorter than the mean intake diameter (d, m) of the blades (2) and an elastic part (5) is present preferably between the impeller crown (3) and the drive element (4).

2. Radial impeller according to claim 1, characterised in that the elastic part (5) is arranged between the blades (2)'and the drive element (4).

3. Radial impeller according to claims 1 and 2, characterised in that the elastic part (5) is part of the blades (2).

4. Radial impeller according to claims 1 and 2, characterised in that the blades are fixed to a continuous ring (6) and the elastic part (5) is constituted by a number of elements (7) differing from the number of the blades (2).

5. Radial impeller according to claims 1, 2 and 4, characterised in that the elements (7) of the elastic part (5) are constructed as a joint.

6. Radial impeller according to claim 1, characterised in that the elastic part (5) is arranged between the impeller covers (1) and the drive element (4).

7. Radial impeller according to claims 1 to 6, characterised in that the drive element (4) consists of plane and/or conical discs.

8. Radial impeller substantially as described with reference to and as illustrated in any of the accompanying drawings.