Impeller

Abstract: The invention concerns an impeller or a propeller for a rotary machine such as a pump, a turbine or a propulsion unit. The impeller comprises a hub (1) and an intermediate part put together by a number of identical hub sections (3) with mounted vanes (4). The partition between two hub sections (3) follows a curve which is substantially axially directed.

Description: The invention concerns an impeller or a propeller for a rotary machine such as a liquid pump of centrifugal or axial type, a turbine or a propulsion unit. An impeller of this type includes a hub attached to a rotary shaft and a number of vanes mounted on the hub or integrated with the latter. A machine of this type is disclosed in US-A-3.386.331, which comprises a central unit, hub, formed by a number of shell formed parts with attached vanes. In the specification below, the technique concerning axial or propeller pumps is dealt with. The invention is however applicable also for other types of impellers and propellers. An axial pump is characterized by the liquid being sucked into the impeller in axial direction and also leaving in axial direction. The kinetic energy obtained by the rotating impeller is transformed into pressure energy by help of a number of fixed vanes downstream of the impeller. Said vanes also normally serve as supporting elements in the pump housing. The vanes mounted on the hub may have different designs depending on the type of liquid to be pumped, the head, etc. The angle between the hub and the vane is of great importance for the pump performance. In certain bigger machines such as turbines, it is common to make the vanes adjustable in order to obtain the best performance at different heads. This solution is of course very expensive and is also sensitive for pollutants. By designing the hub with a spheric surface upon which the vanes are mounted, it is obtained that different vane angles may be chosen without the need to change the vane itself. The purpose of the invention is to obtain an impeller which is easy an inexpensive to produce and possible to adapt for different types of liquids and operation conditions. The invention is discribed more closely below with reference to the enclosed drawing which shows an explosion view of an impeller according to the invention. In the drawing 1 stands for a hub having a flange 2. 3 stands for sections in an intermediate part, 4 vanes mounted on said sections and 5 an end part. 6 and 7 stand for opposing sectional areas in the partition between the sections 3. 8 and 9 finally stand for shoulders and notches resp. on the areas 6 and 7. An impeller or a propeller according to the invention includes a hub 1 to be mounted on a driving shaft, not shown. The hub is provided with a flange 2 for connection to an intermediate part by any suitable means such as bolts. Said intermediate part being formed by a number of identical parts, each comprising a hub section 3 and a vane 4. The hub sections are arranged to be attached to each other, for instance by glueing, along essantially axially directed cuts and also to the flange 2 on the hub 1 and to the end part 5. As can be understood from the above and from the drawing, the parts forming the intermediate part are identical and the partitions between them are essentially axially directed. This brings about certain manufacturing advantages. The division of the impeller into three units along radial cuts results in further advantages. As previously mentioned, different types of vanes, different angles etc are needed in order to obtain optimum results during varying outer conditions depending on the pumped liquid, head, volume etc. The invention makes it possible to use the same parts 1 and 5 for a big variety of impellers and propellers. There is only necessary to vary the intermediate part, but as this consists of a a number of identical parts, a substantial standardization is obtained and consequently a decrease of cost. The partition between two sections 3 is located halfway between two adjacent vanes 4 for resistance reasons. The partition cut following a curve having essentially the same route as the connection line between the vane and the hub section. The ends of the cut are however deviate and are given route mainly perpendicular to the partitions between the intermediate part and the hub and the end part resp, thereby diminishing the shearing forces which try to dislocate the sections relative each other at certain conditions. According to a development of the invention the opposing sectional areas 6 and 7 in each partition are provided with shoulders and corresponding notches 8 and 9 resp. By help of this means and a supplementary gluing joint, a secure mutual locking of the sections is obtained According to a further development of the invention the shoulders and notches resp. are designed with lateral surfaces which are oblique with regard to the areas 6 and 7 resp. In this way the strength is increased. By arranging two of said oblique opposing areas in a plane perpendicular to the rotary shaft of the impeller and in parallel with the planes through the connections between the intermediate part and the flange 2 and the end part 5 resp., certain advantages concerning manufacturing are obtained.

Claims: An impeller or a propeller for a rotary machine such as a liquid pump of centrifugal or axial type, a turbine or a propulsion unit, said impeller or propeller comprising a central part with a number of vanes attached to its periphery, said central part including a hub (1) with a flange (2), an intermediate part and an end part (5), said intermediate part being put together by a number of identical hub sections (3) each one provided with a vane (4), the partitions between said sections (3) having substantially axially directed routes and where the partition between the sections (3) is located half-way between two adjacent vanes (4), characterized in, that each one of said partition cuts follows a curve which has substantially the same route as the connection line between a vane (4) and its hub section (3), and that the ends of said partition cuts deviate from said curve and are given a route substantially perpendicular to the partitions between the intermediate part and the flange (2) of the hub part (3) and the end part (5) resp. An impeller or a propeller according to claim 1, characterized in, that the opposing sectional areas (6) and (7) are provided with shoulders (8) and corresponding notches (9) for securing of the parts, the shoulders and notches being designed with lateral surfaces which are oblique with regard to the areas (6) and (7) and where two of said lateral surfaces are in a plane perpendicular to the rotary shaft of the impeller. An impeller or a propeller according to claim 1, characterized in, that the flange (2) of the hub part and the end part (5) are provided with flanges which encircles opposing flanges on the intermediate part.

Inventors: ARVIDSSON ANDREAS, RINGBLOM TOMAS, ARVIDSSON, ANDREAS, RINGBLOM, TOMAS
Applicants: ITT MFG ENTERPRISES INC, ITT MANUFACTURING ENTERPRISES, INC.
Application year: 1999
Main classification: F04D29
IPC codes: F04D29, B63H1