DESC:HIGH VOLUME LOW SPEED FAN ASSEMBLY
Field of the invention:
The present invention generally relates to an air-circulating fan, and more particularly, to high volume, low speed fans that are used for circulating large volume of air for cooling enclosures containing individuals or animals.
Background of the invention:
HVLS (High Volume Low Speed) fans are types of fans typically having a diameter greater than 7 feet/ 2.1 meters. These fans initially found application in animal husbandry wherein they were used for cooling enclosures containing cattle in order to increase dairy production. The current application of these fans extends to large buildings like warehouses, hangars, airports, churches, shopping malls, etc. to provide cooling when air conditioning is not feasible due to large area. A typical HVLS fan consists of a plurality of pitched blades radially positioned on a rotatable hub. The diameter of such fans typically ranges from 8 ft to 24 ft. The existing HVLS fans can be broadly divided into two categories: Ceiling mounted and pole mounted.
In case of the ceiling mounted variant, the fan chassis is mounted onto a beam by virtue of a top plate, a bottom plate with sector brackets and a square tube that allows 2 degrees of freedom of 20° inclination each. In case of the pole mounted variant, the fan chassis is mounted atop a pole that is secured to the ground by virtue of a base plate and gussets. One of the main shortcomings of the existing invention is that, the entire fan blade sub-assembly is secured using a center bolt which functions as a primary safety mechanism. An anti-fall system is also implemented as a secondary safety mechanism. In addition to this, the existing assembly requires different components for each of the four fan variants (discounting the motor and blades, which need to have a different power rating and length respectively).

There exists a need to optimize the dihedral blade angle of the HVLS fan that will increase the coverage area of the fan without compromising on the downward airflow.
Objects of the invention:
An object of the present invention is to provide a high volume, low speed fan with assembly optimized dihedral blade angle which increases the coverage area of the fan without compromising on the downward airflow.
Another object of the present invention is to provide a high volume, low speed fan assembly with an integrated deep grove ball bearing that will completely eliminate the axial load on the center bolt and improve the build and safety of the HVLS fan.
Yet another object of the invention is to provide a HVLS fan with a lighter blade design that provides a superior capacity to withstand bending loads when the blade is mounted onto the impeller arm.
Yet another object of the invention is to provide a HVLS fan with more degrees of freedom to facilitate mounting of the fan on inclined surfaces
Still another object of the invention is to provide a HVLS fan with an anti-fall mechanism for preventing any components of the assembly from collapsing in case of a structural failure.
Summary of the invention
The present invention discloses a high volume, low speed fan assembly comprising a mounting sub-assembly, a chassis sub-assembly and a fan blade sub-assembly. The mounting sub-assembly for mounting a square tube with +/- 20° freedom of rotation includes a first ceiling bracket mounted on an I beam is secured to a second ceiling bracket with securing means. Two sector brackets are welded to the second ceiling bracket for securing one end of the square tube there between. The chassis sub-assembly is having a motor fitted between a top plate and a bottom plate with its shaft extending through the bottom plate. The other end of the square tube is secured between other two square brackets welded on the top plate of the chassis sub-assembly with +/- 20° freedom of rotation. Two plates for locking the wire-rope are welded onto a first long member and a second long member fitted between the top plate and the bottom plate. The fan blade sub-assembly includes multiple impeller arms with an inclination of 9° bolted on a hub. A fan-blade is secured onto each of the multiple impeller arms with an end-cap fastened at the tip of each fan blade. Each fan blade is configured with a pocket along the length thereof to contain the wire-rope there along. The fan blade sub-assembly is secured using a center bolt and it is loaded onto a bearing contained within a bearing housing fastened onto the bottom plate thereby reducing the axial load exerted onto the center bolt. The adapter which is the primary support of the fan blade sub-assembly resting upon the inner race of the bearing is fitted onto the shaft which transfers the motor torque to the adapter via a keyway. In an embodiment, the bearing is a deep groove ball bearing with a dynamic load rating of 41.6 kN and a static load rating of 122 kN. Each fan blade is configured with a pocket along the length thereof to contain the wire-rope coated with 2 mm PVC coating there along, to minimize vibrations and noise.
Brief description of the drawings:
The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figure 1 shows an isometric view of high volume, low speed fan, in accordance with the present invention;
Figure 2 shows a detailed view of the mounting assembly for securing the fan assembly onto the beam, in accordance with the present invention;
Figure 3 shows a detailed view of the chassis component of HVLS fan assembly in accordance with the present invention;
Figure 4a and 4b show a detailed view of the arrangement for mounting of the sub-assembly of HVLS fan assembly onto inclined surfaces, in accordance with the present invention;
Figure 4c and 4d show a detailed view of the arrangement for mounting of the chassis component of HVLS fan assembly onto inclined surfaces, in accordance with the present invention;
Figure 5 shows a side view of the HVLS fan blade assembly depicting the dihedral angle, in accordance with the present invention;
Figure 6 shows a cut-section of the blade of HVLS fan assembly, in accordance with the present invention;
Figure 7 shows a cut-section of the blade depicting the end-cap and impeller assembly, in accordance with the present invention;
Figure 8 shows a sectional view of a rotating hub of HVLS fan assembly, in accordance with the present invention; and
Figure 9 shows an exploded view of HVLS fan assembly, in accordance with the present invention.
Detailed description of the embodiments:
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
Accordingly, the present invention provides a high volume low speed fan assembly with improved design fan that integrates a deep groove ball bearing within the fan assembly with a two-piece hub, i.e. a main hub and an adapter, the purpose of which is to reduce the axial load exerted onto the center bolt, which typically bears the entire weight of the assembly. Additionally, the blades have been modified structurally and a dihedral angle of 9º has been introduced in order to increase the coverage area. Furthermore, the mounting assembly has been improved in order to facilitate mounting on inclined surfaces or members.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description. Table 1 below enlists the reference numerals and corresponding parts description.
Table 1:
Number Description Number Description
20 Mounting sub-assembly 32 Motor shaft
40 Chassis sub-assembly 34 Long members
60 Fan blade sub-assembly 36 wire-rope holding plates
2 First ceiling bracket 42 Adaptor
4 Second sealing bracket 44 Hub
6 Sector brackets 46 Impeller arms
7 Sector bracket slot 47 Hub Cover
8 Square tube 48 Fan-blades
10 Studs 50 End-caps
12 Fasteners 52 Wire rope
22 Top plate 54 Bearing
24 Bottom plate 55 Bearing support plate
26A First pair of gusset plates 56 Bearing housing
26 B Second pair of gusset plates 58 Centre bolt
28 Cover plates 62 Box section
30 Motor 64 Pocket
Referring to figures 1 to 8, a high volume, low speed fan assembly (100) (hereinafter referred as “the assembly (100)”) is shown. The assembly (100) mainly comprises of a mounting sub-assembly (20), a chassis sub-assembly (40) and a fan blade sub-assembly (60).
The mounting sub-assembly (20) includes a first ceiling bracket (2) and a second ceiling bracket (4) for mounting onto an I-beam (not shown) and secured with studs (10). Two sector brackets (6) are welded to the other side of the second ceiling bracket (4) and a square tube (8) is secured there between at one end thereof, using fasteners (12). The sector brackets (6) are configured with a slot (7) along which the fastener (12) can be moved and clamped at any conventional position. This arrangement allows for +/- 20° freedom of rotation for mounting onto inclined surfaces.
The chassis sub-assembly (40) includes a top plate (22), a bottom plate (24), a motor (30), a first pair of gusset plates (26A), a second pair of gusset plates (26B), two motor covers (28), two long members (34) and a wire rope holding plate (36). In the chassis subassembly (40), two sector brackets (6) configured with the slot (7) are welded to the top plate (22) and the square tube (8) is secured there between using fasteners (12). The fastener (12) can be moved along the slot (7) and clamped at any conventional position allowing +/- 20° freedom of rotation for inclined mounting along an axis perpendicular to the inclined mounting at the one end of the square tube (8). The bottom plate (24) is secured below the top plate (22) using two long members (34); and a motor (30) is secured to the bottom plate (24) between the top plate (22) and the bottom plate (24). In an embodiment, the motor (30) is any one selected from Asynchronous Geared Motor, BLDC (Brushless Direct Current) or PMSM (Permanent Magnet Synchronous Motor) having a power rating from 0.55 kW to 1.5 kW based on the type of motor being used and the diameter of the fan that it is being used for. The motor (30) is bolted onto the bottom plate (24) by means of fasteners (12), preferably four M10 fasteners. Two wire-rope holding plates (36) are also welded between the top plate (22) and the bottom plate (24) onto a first long member (34) and a second-long member (34).
The fan blade sub-assembly (60) includes an adaptor (42) and a hub (44) driven by a motor shaft (32) by virtue of a keyway mechanism. A bearing (54) with a bearing housing (56) and bearing support plate (55) is secured onto the hub (44). The bearing (54) is preferably a deep groove ball bearing. The bearing housing (56) is bolted below the bottom plate (24) by means of the same fasteners (12) used for bolting the motor (30). Multiple Impeller arms (46) ranging from 3 to 6 are bolted to the hub (44). In a characteristic embodiment, five impeller arms (46) are bolted to the hub (44). In another characteristic embodiment, the impeller arms (46) are machined at an inclination 9° in order to achieve the desired dihedral angle. A fan-blade (48) having an end-cap (50) fastened at the tip thereof is secured onto each of the multiple impeller arms (46). The end-cap (50) reduces the subsequent vortexes that are generated at the tips. The entire fan blade assembly is loaded onto the bearing (54) as borne by the flange of the adapter (42). In an embodiment, the bearing (54) is a deep groove ball bearing (code: 6212-2RS1) with a dynamic load rating of 41.6 kN and a static load rating of 122 kN.
Figure 4 presents a side view of the fan blade sub-assembly (60) secured to the chassis sub-assembly (40) with selective components which accurately depicts the 9° dihedral angle. The fan-blades (48) are inclined at an angle of attack of 3 degrees and a dihedral angle of 9 degrees.
Referring now to figure 5 a cut section of the fan-blade (48) is shown. The overall wall thickness has been maintained to a minimal degree within safety limits and the box section (62) that houses the impeller arm (46) has been reinforced for greater structural strength. The final weight of the blade (48) has also reduced by almost 1.5 kilograms in the process. Furthermore, a pocket (64) has been provided along the length of the fan-blade (48) to contain a wire-rope (52) and effectively counter the problem of undue vibrations and sound caused by its movement during operation. In an embodiment, the wire rope (52) with 2 mm PVC coating is embedded within the pocket (64) along the length of the blade to minimize undue vibrations and noise. Figure 6, shows a cut section of the fan-blade (48) along with the end-cap (50). Also shown is a cross-section of the wire-rope (52) contained within the pocket (64).
The assembly (100) is able to achieve a weight reduction of close to 14 kilograms without compromising on structural rigidity and safety. This has been mainly achieved in the impeller-blade assembly, wherein the number of impeller arms (20) has been reduced from six to five. Additionally, the blade (8) has been redesigned to be both lighter and safer, and the weight of the hub-impeller (20 and 21) assembly has also been reduced significantly. The modified blade (8) design also means that the difficulty in manufacturing the blade (8) by extrusion of aluminum (Al 6061 T6) was significantly greater due to the reduced wall thickness.
For the purpose of validating the invention in question, a comprehensive CFD analysis has been performed in order to effectively gauge the coverage area of the fan and the net volumetric flow rate achieved. Air velocity at 0.8m and at 1m height was measured up to 30m periphery of the coverage area. Table 2 below shows comparison between coverage area of the HVLS fan having normal dihedral angle of impeller blades and the HVLS fan of the present invention having dihedral angle of 9°.
Normal Blade Angle Dihedral Blade Angle of 9°
Distance from the centre (m) Air velocity at 0.8 m (from floor) Air velocity at 1 m (from floor) Air velocity at 0.8 m (from floor) Air velocity at 1 m (from floor)
1 0.6 1.1 1.6 1.5
2 2 1.6 1.9 1.7
3 3.2 3.6 2.4 2.4
4 2.3 3.3 2.7 2.8
5 1.6 3.1 2.5 2.1
6 1.7 2.8 2.8 2.7
7 1.2 2.5 2.6 2.4
8 1.1 1.8 2 2.1
9 0.9 1.5 2.7 2.2
10 1.1 1.3 2.8 2.6
11 1.5 1.1 2.1 2.2
12 1.3 1.4 2.5 2
13 1.1 1.4 1.7 1.6
14 1.6 1.2 1.8 1.7
15 0.9 1 2.4 2.4
16 0.7 1 2.5 2.3
17 0.8 0.9 2.3 2.1
18 0.4 0.5 2.2 2.2
19 0.9 0.8 1.8 1.8
20 0.6 0.7 2.2 2.1
21 0.6 0.6 2.2 2.2
22 0.5 0.5 1.9 1.9
23 0.3 0.5 1.4 1.2
24 0.1 0.2 1.3 1.2
25 0 0.1 1.4 1.5
26 0 0 1.3 1.2
27 0 0 1.3 1.4
28 0 0 0.9 0.9
29 0 0 1.3 1.2
30 0 0 1.2 1.2

It is clear from the above Table 2 that HVLS fan of the present invention having impeller blades with dihedral angle of 9° effectively cover more area than the HVLS fans having normal blade angle.
Advantages of the invention:
? Number of impeller blades is reduced from six to five and blades are designed to be lighter and safer, resulting in reduction of nearly 14 kg in the assembly (100).
? The assembly (100) with optimized dihedral blade angle increases the coverage area of the fan without compromising on the downward airflow.
? The arrangement of integrated deep groove ball bearing completely eliminates the axial load on the center bolt and improves the build and safety of the assembly (100).
? Lighter blade design provides a superior capacity to withstand bending loads when the fan-blade (48) is mounted onto the impeller arm (46).
? The assembly (100) has more degrees of freedom to facilitate mounting of on inclined surfaces.
? The anti-fall mechanism provided in the assembly (100) prevents any components of the assembly from collapsing in case of a structural failure.
? The old HVLS assembly requires different components for each of the four fan variants (discounting the motor and blades, which need to have a different power rating and length respectively). The assembly (100) solves this problem by standardizing all the components so they can be used for every fan variant.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention.

,CLAIMS:We claim:
1. A high volume, low speed fan assembly (100) comprising:
a mounting sub-assembly (20) having a first ceiling bracket (2) secured to a second ceiling bracket (4) with the first ceiling bracket mounted to an I beam and the second ceiling bracket (4) having two sector brackets (6) welded thereto for securing one end of a square tube (8) there between with a fastening means (12);
a chassis sub-assembly (40) fitted to the other end of the square tube (8), the chassis sub-assembly (40) having a motor (30) secured between a top plate (22) and a bottom plate (24) with a motor shaft (32) extending through the bottom plate (24), two sector brackets (6) welded to the top plate (22) for securing the other end of the square tube (8) there between with the fastening means (12); and two plates (36) for holding a wire-rope (52) secured between the top plate (22) and the bottom plate (24) with twolong members (34); wherein the sector brackets (6) holding the two ends of the square tube (8) are configured with a slot (7) for adjustably fitting the fastening means (12) to allow +/- 20° freedom of rotation for inclined mounting;
a fan blade sub-assembly (60) having a multiple impeller arms (46) bolted on a hub (44) with an inclination of 9°, the fan blade sub-assembly (60) having a fan-blade (48) secured onto each of the multiple impeller arms (46), each fan blade (48) having an end-cap (50) fastened at the tip thereof and configured with a pocket (64) along the length thereof to contain the wire-rope (52) there along, wherein the fan blade sub-assembly (60) secured using a center bolt (58) is loaded onto a bearing (54) with a bearing housing (56) secured onto the hub (44) receiving the motor shaft (32) through an adaptor (42) thereby reducing the axial load exerted onto the center bolt (58), wherein the bearing (54) is a deep groove ball bearing.
2. The high volume, low speed fan assembly (100), wherein the motor (30) is any one selected from an asynchronous geared motor, brushless direct current motor and a permanent magnet synchronous motor.
3. The high volume, low speed fan assembly (100), wherein the motor (30) is having power rating from 0.55 kW to 1.5 kW based on the type of motor and the diameter of the fan.
4. The high volume, low speed fan assembly (100), wherein the wire rope (52) is coated with 2 mm PVC coating to minimize vibrations and noise.
5. The high volume, low speed fan assembly (100), wherein the bearing (54) is a deep groove ball bearing with a dynamic load rating of 41.6 kN and a static load rating of 122 kN.
6. The high volume, low speed fan assembly (100), wherein number of impeller arms (46) bolted on the hub (44) ranges from 3 to 6.
7. The high volume, low speed fan assembly (100), wherein the fan blade (48) is configured with a box section (62) for housing the impeller arm (46) therein.
Dated this on 28th day of January, 2020

Ashwini Kelkar
(Agent for the applicant)
(IN/PA-2461)