GB2372784A

GB2372784A - Air Turbine Interlocking Blade Root and Hub Assembly

Info

Publication number: GB2372784A
Application number: GB0028670A
Authority: GB
Inventors: Peter James Anderson
Original assignee: ECLECTIC ENERGY Ltd
Current assignee: ECLECTIC ENERGY Ltd
Priority date: 2000-11-24
Filing date: 2000-11-24
Publication date: 2002-09-04
Also published as: GB0028670D0

Abstract

An arrangement for rapid assembly of an air turbine having several blades, each blade interlocking with an adjacent blade at the blade root. The turbine is assembled by axially sliding keys on each blade root with keyways on the adjacent blade root in an interlocking manner. A hub and clamping plate are provided which when tightened through the assembled blade roots enhances the positional accuracy and rigidity of the blades and provides additional structural strength of the turbine assembly. The radial angular geometry of the blade root determines the number of blades in the complete turbine assembly. The blade root may have a tapered recess on one face and an annular recess 9 and annular dimples 11 on the other face to facilitate the locking action of the turbine hub and clamping plate. The hub may have a clamping face incorporating tapered pins which cooperate with the tapered recess in the blade root. The clamp plate has means to releasably secure it to the hub.

Description

AIR TURBINE BLADE ROOT AND HUB ASSEMBLY This invention relates to an air turbine root and hub which allows for rapid assembly or disassembly of small and medium sized air turbines, without the use of tools.

Air turbine blades are often manufactured individually, and then attached to a hub using threaded fasteners. This provides for a semi-permanent method of constructing the full turbine assembly. Although such an assembly can be dismantled to facilitate the replacement of blades, this can be a difficult and time-consuming process.

The object of this invention is to provide a quick, simple and secure way of assembling and disassembling the turbine for transport or storage, and/or replacement of damaged blades.

This feature is of particular value in applications where the electrical machine is capable of both wind and water generation, or where the turbine needs to be rapidly re-deployed in another location.

Accordingly, this invention provides a method of rapidly assembling a complete air turbine from a set of turbine blades by axially sliding keys on each blade root into corresponding keyways on the adjacent blade, and disassembling by reversing the process. The invention further provides for a hub and clamping plate which, when tightened through the blade roots, enhance the positional accuracy and rigidity of the blades, and provide for additional structural strength of the turbine assembly.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a plan view of the forward face of a typical blade root.

Figure 2 shows a plan view of the rear of a typical turbine assembly, consisting of five blade roots.

Figure 3 shows a side elevation of a typical air turbine hub.

Figure 4 shows a perspective view of the forward face of a typical blade root.

Figure 5 shows a perspective view of the inner face of a typical hub.

Figure 6 shows a perspective view of the outer face of a typical clamping plate.

Figure 7 shows a perspective view of the inner face of a typical clamping plate.

Figure 8 shows a perspective view of the rear face of a typical blade root.

The blade root is provided as shown in Figure 1. The geometry of this element is determined by the number of blades in the completed turbine, and the designed area of the hub. Each blade root element is provided with, on one side a keyway 1, and on the other side a key 2.

When two blades are brought together, the key 2 of one slides axially into the keyway 1 of the other, thus connecting the blades together. This process is repeated sequentially with each blade until the turbine is complete, as illustrated in Figure 2.

In order to provide further security and integrity to the turbine, and to provide a mounting point and axis, a hub and mounting plate are provided. The hub shown in Figure 3 is provided with tapered pins 3 on its clamping face which locate in tapered recesses 4 in the blade roots, as shown in Figure 4. The tapered recesses in the blade roots appear on one side of the blade root only, therefore ensuring that the turbine blades cannot be assembled to the hub back to front.

The hub is provided with a hollow spigot 5 which is externally threaded 6 on one end, as shown in Figure 5. The spigot 5 is passed through the hole formed by the assembled blade roots, the tapered pins 3 locating in the tapered recesses 4 in the blade roots. The clamping plate, as shown in Figure 6, is internally threaded 7 to suit the male thread 6 on the hub. The clamping plate is screwed to the hub, thereby clamping the turbine blade roots.

As shown in Figure 7, the clamping plate is provided with a raised annular section 8 on its inner face which locates progressively within an annular recess 9 in the blade roots, as in Figures 8 and 2.

As the clamping plate is tightened up, the action of the keyways 1 and keys 2 in the blade roots, tapered pins 3 on the hub and tapered recesses 4 on the blade roots, and the annular raised ring 7 on the clamping plate and annular recess 9 on the blade roots combine to align the blades and to lock the turbine assembly rigidly together. In order to prevent the clamping plate from unscrewing due to vibration, the clamping plate is provided with two spring ball plungers 10 or similar devices of known design on its inner face. These bear on indentations 11 arranged annularly on the rear face of the blade roots, and prevent vibration from loosening the clamping plate. The clamping plate is provided with a means by which it can afford a purchase to the hand 12, allowing it to be tightened and loosened. To dismantle the turbine, the lugs 12 on the clamping plate are grasped and the clamping plate is unscrewed against the friction of the ball plungers 10.

Once the clamping plate has been unscrewed and removed, the spigot 5 can be withdrawn through the hole in the centre of the assembled turbine blade roots. Each turbine blade root can now be separated from its adjacent root by axially sliding and disengaging the keys 2 from the keyways 1. The turbine is now disassembled to facilitate repair, transport or storage.

Claims

CLAIMS 1. A complete air turbine assembly is rapidly assembled from a multiplicity of turbine blades by axially sliding keys on each blade root into corresponding keyways on the adjacent blade, and disassembling by reversing the process, a hub and clamping plate being provided which, when tightened through the assembled blade roots, enhance the positional accuracy and rigidity of the blades and provide for additional structural strength of the turbine assembly.
2. An air turbine blade root and hub assembly as claimed in Claim 1 wherein each blade root is provided with a key on one side and a keyway on the other, arranged radially such that when two blades are brought together the key of one slides axially into the keyway of the other.
3. An air turbine blade root and hub assembly as claimed in Claim 1 or 2 wherein by continuing to axially slide blade keys into adjacent blade keyways, a complete turbine is formed.
4. An air turbine blade root and hub assembly as claimed in Claim 1,2 or 3 in which the radial angular geometry of the blade root is determined by the desired multiplicity of blades in the completed turbine assembly.
5. An air turbine hub and blade root assembly as claimed in any preceding claim in which the blade root incorporates tapered recesses on one face and an annular recess and annular dimples on the other face to facilitate the locking action of the turbine hub and clamping plate.
6. An air turbine blade root and hub assembly as claimed in any preceding claim wherein a hub and clamping plate are provided.
7. An air turbine blade root and hub assembly as claimed in any preceding claim wherein the hub is provided with a clamping face incorporating tapered pins which correspond to the tapered recesses in the blade root together with a spigot which passes through the hole in the assembled air turbine blade roots.
8. An air turbine blade root and hub assembly as claimed in any preceding claim wherein the hub spigot is provided with a means to releasably secure the clamping plate, the clamping plate being provided with a means which affords purchase to the hand, allowing it to be secured and released.
9. An air turbine blade root and hub assembly as claimed in any preceding claim wherein a clamping plate is provided with a raised annular section on its inner face which progressively locates within the annular recess in the blade roots as the clamping plate is secured.
10. An air turbine root and hub assembly as claimed in any preceding claim wherein the clamping plate is provided with a means to prevent unintentional release.
11. An air turbine blade root and hub assembly substantially as described herein with reference to Figures 1 to 8 of the accompanying drawings.