US3324953A

US3324953A - Fan rotors

Info

Publication number: US3324953A
Application number: US505542A
Authority: US
Inventors: Ronald H Greenhill
Original assignee: Airscrew Weyroc Ltd
Current assignee: Ametek Airtechnology Group Ltd
Priority date: 1964-10-29
Filing date: 1965-10-28
Publication date: 1967-06-13
Anticipated expiration: 1984-06-13

Description

June 13, 1967 R. H. GREENHILL FAN ROTORS 5 Sheets-Sheet 1 Filed Oct. 28, 1965 ATTORNEY.

June 13, 1967 R. H. GREENHILL 3,324,953

FAN ROTORS Filed Oct. 28, 1965 5 Sheets-Sheet 2 AE MENTOR:

Paw/140 41m? VG/Fif/W/ML Va flag/Ma ATTORNEY.

June 13, 1Q67 H GREENHILL 3,324,953

FAN HOTORS Filed Oct. 28, 1965 5 Sheets-Sheet 5 INVENTORI Pan/4L0 62 Y GEEE/VH/L 4 ATTORNEY June 33, E967 R. H. GREENHILL. 3,32 ,953

FAN ROTORS Filed Oct. 28, 1965 5 Sheets-Sheet 4 W INVENTOR'.

M 4/ www- ATTORNEY.

FAN ROTORS Filed Oct. 28, 1965 5 Sheets-Sheet s INVENTORZ flow/I40 flmvr Gleam/m 4 ATTORNEY.

United States Patent 3,324,953 FAN ROTORS Ronald H. Grecnhill, Knaphill, England, assignor to Airscrew-Weyroc Limited, Weybridge, Surrey, England, a company of Great Britain Filed Oct. 28, 1965, Ser. No. 505,542 Claims priority, application Great Britain, Oct. 29, 1964, 44,202/64 2 Claims. (Cl. 170-160.6)

This invention relates to the construction of fan rotors of the type (called later the type described) built up from a hub and a number of blades secured to the hub so as to extend more or less radially therefrom. The invention is more especially though not exclusively concerned with rotors for the larger sizes of axial fan e.g. Where the rotor may have a diameter from 7 to 40' and absorb tens to hundreds of horsepower.

The main object of the invention is to facilitate the construction and assembly of fan rotors of the type described, and more particularly to enable accurate setting of the blades at a desired angle.

With this object in view the invention provides a fan rotor of the type described wherein each blade root is secured to the hub together with a locating member and means are provided for positively locating the locating member in angular position with respect both to the hub and to the blade root to determine the angular setting of the blade relative to the hub. In this way it is possible to achieve a desired angular setting without the use of measuring instruments during assembly of the rotor. The means for angularly locating the hub and blade root may be dowels or the like; this locating means is preferably independent of the means by which the blade roots are secured to the hub and such as to prevent assembly of the blades with the hub except at the desired setting. This ensures that the rotor is correctly assembled despite problems such as may arise in difiicult locations or with only partially skilled labour. Also, if it is desired to change the angular setting of the blades, the intermediate members can be exchanged for aonther set of such members providing a different setting. If it is contemplated that a given rotor will from time to time have its blades re-set to different angles, then a series of sets of intermediate members are provided, each set providing a given setting different from that of the next set; for example the sets may provide 2 steps between a maximum and a minimum angle. The blade settings of such a rotor can be checked by inspection of the sets of intermediate members not in use.

One embodiment of the invention is illustrated in the accompanying drawings in which:-

FIGURE 1 is a partial axial section through a large axial fan rotor showing only partially the hub and one blade thereof;

FIGURE 2 is a radial view of what is shown in FIG- URE 1, seen looking in the direction of the arrow Y therein;

FIGURE 3 is a view similar to FIGURE 2 but showing the blade set at a difierent angle;

FIGURE 4 is a section on the line A-A of FIGURE 2;

FIGURE 5 is an end elevation of a further form of hub;

FIGURE 6 is an axial section of the FIGURE 5 hub;

FIGURE 7 is a partial axial section of yet another form of axial fan rotor;

FIGURE 8 is a view seen along the arrow VIII in FIG- URE 7, and

FIGURE 9 is a partial end elevation of the FIGURE 7 rotor.

Referring to FIGURES 1 to 4 of the drawings, the rotor illustrated is built up from a hub designated gen- Patented June 13, 1967 erally 1 and a number of blades 2 secured thereto. The huh 1 comprises pairs of spaced plates 3 secured together and mounted (by means not shown) on a drive shaft so as to extend perpendicularly to the axis of rotation. The plates 3 carry inwardly-facing spaced lips 4 at intervals and it is on these that the blades are mounted. Each blade 2 includes a root 5 of reduced dimensions having 'a circular flange 6 at is base. The blade root flange 6 is secured by bolts 7 to an intermediate member in the form of a pair of setting plates 8 extending across the lips 4 on the hub 1 and secured thereto by bolts 9, the flange 6 and lips 4 sandwiching the setting plates between them on the inside of the lips. A pair of dowels 10 on the top side of one setting plate 8a extend into holes on the underside of the lips 4. Another pair of dowels 11 on the lower side of the setting plate 8a fit into holes at the top of the blade root flange 6.

The rotor is assembled by attaching the setting plates 8 to the blade root flange 6, dropping the blade root 5 between the hub plates 3 between adjacent sets of lips 4, then moving the hub or blade to bring the root under a pair of lips, and finally offering up and securing the plates 8 to the lips.

The

dowels

10, 11 are accurately positioned in the workshop prior to assembly of the rotor. The relative positions of the dowels determine the blade setting after assembly. No measurements are required during assembly, and it will be seen that if the parts fit together, then the desired setting must be obtained, since they cannot fit in any but the right position.

If it is desired to change the blade angles, a different set of setting plates is fitted, e.g. the plates 8 of FIGURE 3; all the parts of this assembly are the same as those of FIGURE 2 except for the relative angular positions of the dowels on the setting plates.

Various modifications are possible in the embodiment described. Thus, either one or both setting plates 8 may carry locating means, and the blade 2 and setting plates 8 can be re-designed so that only one plate is required. The hub 1 can be constructed in any desired manner. The blade root flange 6 and lips 4 may sandwich the setting plates on the outside of the latter, rather than on the inside as shown, but in this case the bolts will have to be strong enough to take the centrifugal and bending forces applied.

One modified form of hub is shown in FIGURES 5 and 6. This hub, designated 1, is designed for fabrication from aluminium plate and extrusions and its general construction will be seen from the FIGURES. The hub 1 provides, for each rotor blade (not shown), a pair of stout angle members 20 having their long limbs 21 eX- tending radially and their short limbs 22 providing a pair of opposed lips similar to the lips 4 above described. In this construction, instead of providing dowels in the setting plates, inwardly projecting dowels 23 are mounted on the members 22 and are received in holes in the setting plates. The dowels between the blade root flanges and the setting plates may be mounted in either of these members; if provided in the flanges the setting plates are simply apertured plates. The blade roots are assembled from the end of the hub 1' through the spaces marked 24.

The fan rotor shown in FIGURES 7 to 9 comprises a hub 1" fabricated in the same general manner as the hub 1 of FIGURES 1 to 4 and once again mounting blades 2. The hub includes side plates 3 welded together and interconnected by a series of blade-mounting platforms 30 formed with large circular holes 31. Each blade 2 has a root 5 with a circular flange 6 as in previous embodiments. The flanges 6 have shoulders 32 and fit in the holes 31 in the blade-mounting platforms 30 with the shoulder seating on the outer faces of the platforms, A setting plate,

here designated 33, extends across the hole 31 in each platform 30 and bears against its lower surface.

Dowel pins

34, 35 secured in the blade flange 6 and in the platform 30 respectively engage in

holes

36, 37 in the setting plate 33, thereby locating the blade 2 in angular position relative to the hub. Bolts 38 extend through the blade flange 6 and engage in threaded holes in the setting plate, so that the platform is clamped between the flange and the plate, and the plate acts to retain the blade on the hub.

Preferably the setting plates 33 are formed with a series of holes permitting assembly at a series of different blade angles. Alternatively, interchangeable plates, each adapted for one particular setting, may be provided to enable the blade angles to be changed.

This embodiment may be modified in various ways. Thus for example the blade root could be rectangular and engaged under the platform, with the setting plate on top of the platform.

I claim:

1. A fan rotor comprising a fabricated hub defining a plurality of blade positions, a pair of spaced lips associated with said hub at each blade position, a plurality of blades, each mounted by its root at one of said blade positions of the hub, and a plurality of setting plates, each blade root being secured to one setting plate and each setting plate being secured to the lips at the respective blade position, a location projection coacting between said setting plate and blade root at each blade position and a second locating projection coacting between the setting plate and lips at each blade position, said locating projections being integral with the parts with which they are associated and being disposed at a fixed predetermined position so as to determine a unique angular location of the blade, and said blade roots being incapable of direct connection to said lips.

2. A fan rotor comprising a fabricated hub defining a plurality of blade positions, a pair of spaced lips asso? ciated with said hub at each blade position, a plurality of blades each mounted by its root at one of said blade position of the hub, and a plurality of setting plates, each blade root being secured to one setting plate radially inwardly thereof and each setting plate being secured to the lips at the respective blade position radially inwardly of said lips, a first pair of dowels coacting between said setting plate and blade root at each blade position and a second pair of dowels coacting between the setting plate and lips at each blade position, said pairs of dowels being disposed at a predetermined position so as to determine a unique angular location of the blade.

References Cited UNITED STATES PATENTS 3,231,022 1/1966 Schroeter et al. -1606 FOREIGN PATENTS 367,265 2/ 1932 Great Britain.

MARTIN P. SCHWADRON, Primary Examiner.

EVERETTE A. POWELL, JR., Examiner.

Claims

1. A FAN ROTOR COMPRISING A FABRICATED HUB DEFINING A PLURALITY OF BLADE POSITIONS, A PAIR OF SPACED LIPS ASSOCIATED WITH SAID HUB AT EACH BLADE POSITION, A PLURALITY OF BLADES, EACH MOUNTED BY ITS ROOT AT ONE OF SAID BLADE POSITIONS OF THE HUB, AND A PLURALITY OF SETTING PLATES, EACH BLADE ROOT BEING SECURED TO ONE SETTING PLATE AND EACH SETTING PLATE BEING SECURED TO THE LIPS AT THE RESPECTIVE BLADE POSITION, A LOCATION PROJECTION COACTING BETWEEN SAID SETTING PLATE AND BLADE ROOT AT EACH BLADE POSITION AND A SECOND LOCATING PROJECTION COATING BETWEEN THE SETTING PLATE AND LIPS TO EACH BLADE POSITION, SAID LOCATING PROJECTIONS BEING INTERGRAL WITH THE PARTS WITH WHICH THEY ARE ASSOCIATED AND BEING DISPOSED AT A FIXED PREDETERMINED POSITION SO AS TO DETERMINE A UNIQUE ANGULAR LOCATION OF THE BLADE, AND SAID BLADE ROOTS BEING INCAPABLE OF DIRECT CONNECTION TO SAID LIPS.