US2573875A - Rotary fan - Google Patents

Description

Nov. 6, 1951 7 R. G. RIDDIFORD 2,573,875

ROTARY FAN Filed Dec. 28, 1945 3 Sheets-Sheet 1 ,0 Has;

P HUD/F04 0 Nov. 6, 1951 R. cs. RIDDIFORD 2,573,875

v ROTARY FAN Filed Dec. 28, 1945 s Sheets-Sheet 2 Nov. 6, 1951 R. G. RIDDIFIORD 2,573,875

ROTARY FAN Filed Dec. 28, 1945 3 Sheets-Sheet 3 Patented Nov. 6, 1951 ROTARY FAN Richard George Riddiford, Weybridge, England, assignor to The Airscrew' Company Limited,

Weybridge, England Application December 28, 1945, Serial No. 637,570 In Great Britain February 14, 1945 2 Claims. (01. 230-134) This invention relates to rotary fans and has for its object to provide an improved construction of fan including an improved method of mounting the rotor blades or the blades of stationary guide vanes.

According to the present invention the mounting ring for the rotor blades or stationary guide blades comprises a series of detachably mounted segments. All, or only selected numbers of these segments are provided with recesses to receive the roots of the blades or vanes. Each recessed segment may be in two parts, each having an open recess, the two parts being clamped, as by bolts, around the blade or vane rootsand to spaced side plates. By providing a series of interchangeable recessed and unrecessed segments it is possible for a range of fans having a different number of impeller blades or stationary vanes to be readily assembled. Accordingly, the necessity of providing a separate rim for each fan in the range is obviated and the cost of production reduced.

To enable the invention to be fully understood it will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a front elevation of part of a fan rotor with the cover plate and one half of the two-part segments removed,

Fig. 2 is a section on the line 2-2 of Fig. 1,

Fig. 3 is a plan of one of the segment halves,

Fig. 4 is a view similar to Fig. 1 but shewing a different arrangement of the fan blades,

Fig. 5 is a front elevation of a hub plate shewing balancing means,

Fig. 6 is an elevation of part of a mounting ring for stationary guide vanes, and

Fig. '7 is a part sectional elevation of a fan unit.

As shewn in the accompanying drawings a fan rotor comprises a plate I having a hub 2 which is keyed to a shaft 3, and a cover plate 4 which is secured to the shaft by a screw 5.

The plates 1 and 4 are spaced apart and provided with annular recesses 6, 1 adjacent to the outer edges. A series of pairs of co-operating segments are assembled between the plates to form a blade mounting ring- As shewn, particularly in Fig. 3, each co-operating segment comprises a block 8 having a concave recess 9 on its inner face and a projection II! on its outer face.

The pairs of segments are assembled round the cylindrical roots H of the blades [2 with the recesses encircling the roots. The projections I0 are entered into the respective recesses 5, l andsecured by bolts l3 extending through the segments and plates I, 4. The bolts are finally tightened to clamp the blades, after the blade has been set to the desired angle.

In Fig. 1 the fan rotor has 16 blades. If, however, a fan with 8, 4 or 2 blades is required, it is merely necessary to replace the requisite number of blade-carrying segments by unrecessed spacer segments of similar size. In Fig. 4 an arrangement of 12-b1aded fan is provided by the use of short spacer segments l4 but it will be readily understood that by the use of spacer segments of different sizes it is possible to build up a fan having any desired number of blades.

An'important advantage of the present invention is that a wide range of fans can be readily assembled, or existing fans altered to vary the number of blades, from a minimum number of parts, and without the necessity of providing a complete one-piece blade mounting ring for each type of fan.

The spacer segments are preferably in one piece, as distinguished from the pairs of cooperating half blocks of the blade mounting segments. The outer face of the spacer segments is preferably plane and unrecessed to avoid setting up undesirable eddy currents.

To enable the rotors to be balanced for each difierent arrangement of blades, alternate webs l5 of the plate I are formed with radial slots IS in which weights I! are slidably mounted and clamped in adjusted position as by bolts.

A modified form of balancing means is shewnin Fig. 5 wherein circumferential slots I8 are formed in the plate I in which weights l9 are slidably mounted and locked as by bolts in adjusted position.

The outer edges of the spaced plates may be radiused in such a manner that the clearance between the edges and the blade is constant irrespective of the angular setting of the blade.

The application of the invention to stationary guide vanes is shewn in Fig. 6 wherein the stationary vanes 20 are each mounted between half blocks- 2! which are substantially similar to the half blocks 8. The pairs of blocks are assembled round the roots 22 of the vanes 20 and the annular series of pairs of blocks are clamped between spaced plates 23, one only of which is shewn in Fig. 6. The mounting of the stationary guide vanes will be substantially the same as that described above in connection with the mounting of rotor blades.

A complete fan unit is shewn in Fig. 7 mounted in a casing 24 and comprises a series of impeller blades 25 mounted in segments 26 which are clamped between plates 21, 28 the plate 28 being keyed to the shaft of the electric motor 29. A series of stationary guide vanes 30 are mounted 'in front of the rotor blades and secured by bolts to the wall of the casing 24. The vanes 3|] are mounted in segments 31 which are clamped between spaced plates 32, 33 and a curved cover plate 34 is secured to the plate 32. If desired, the stationary guide vane unit may be arranged behind instead of in front of the rotor blades.

I claim:

1. A mounting ring for the detachable reception of blades to function either as the rotor blades of a rotary fan or as stationary guide vanes in a fan unit, said mounting ring being in the form of a wheel-like structure and comprising a series of blocks adapted on assembly to abut one against the other and form a continuous ring constituting the rim of the wheel-like structure and. also to provide a series of clamps for releasably holding by their roots a predetermined number of blades so that each blade is separately detachable and angularly adjustable by a turning movement about its axis, spaced side plates on opposite sides of the continuous ring of blocks. and of substantially the same diameter as said ring and means for pulling said side plates together so as tov clamp tightly betweenthem the said blocks, the arrangement being such as to permit the number of blades to be varied and the continuity of the ring'of blocks maintained.

2. A mounting ring for the detachable reception of blades to function either as the rotor blades of a rotary fan or as stationary guide vanes 4 in a fan unit, said mounting ring being in the form of a wheel-like structure and comprising a series of blocks adapted on assembly to abut one against the other and form a continuous ring constituting the rim of the Wheel-like structure some of said blocks comprising two co-operating parts each providing half of a central cylindrical opening for receiving the root of a blade to provide a series of clamps for releasably holding by their roots a predetermined number of blades so that each blade is separately detachable and angularly adjustable by a turning movement about its axis, spaced side plates on opposite sides of the continuous ring of blocks and of substantially the same diameter as said ring and means for pulling said side plates together so as to clamp tightly between them'the said blocks, the arrangement being such as to permit the number of blades to be varied and the continuity of the ring of blocks maintained by substituting a solid block for the blade engaging blocks from which a blade has been removed.

RICHARD GEORGE RIDDIFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,191,341 Curley Feb. 20, 1940 2,232,670 Barrett Feb. 18, 1941 2,298,576 McElroy et al Oct. 13, 1942 2,307,490 Curley Jan. 5, 1943 2,382,535 Bauer Aug. 14, 1945

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