DESC:CEILING FAN BLADE ASSEMBLY
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a ceiling fan assembly, in particular, to a blade of ceiling fan with convex shaped profile having variable twist angle along length of the blade for higher air delivery.
BACKGROUND AND PRIOR ART:
[002] Generally, ceiling fans are powered by electric motors for circulating air. The ceiling fan has a motor within housing, i.e., hub mounted to a down rod that rotates a plurality of fan blades connected with the motor about the axis of the down rod. Their blades have traditionally been flat and oriented at an incline or pitch to present an angle of attack to the air mass in which they rotate. This causes air to be driven downwardly.
[003] When a fan blade that extends generally radially from its axis of rotation is rotated, its tip end travels in a far longer path of travel than does its root end for any given time. Thus, its tip end travels much faster than its root end. To balance the load of wind resistance along the blades, and the air flow generated by their movement, fan blades have been designed with an angle of attack that diminishes towards the tip.
[004] The ceiling fan or axial fan is suspended above the ground, the ceiling fan sucks air radially. This means that the air flow is not fully perpendicular to the fan blades. Also, wind causes variations in the air flow direction relative to the fan blade. This variation in air flow direction relative to the fan blades causes a non- optimal functioning of the fan. It is known to use twisted fan blades to optimize the aerodynamic angle of attack of the fan blade. However, due to wind and to other particular conditions that can create turbulence at the outboard edge of the blade, twisting of the fan blade does not provide an optimal solution for the outboard edge zone of a fan blade. These conditions could cause such an air flow direction relative to the tip of the fan blade, that stall can occur in the outboard edge zone resulting in lower performance, lower efficiency of the fan blade and causing extra noise.
[005] Existing ceiling fan has a typical motor diameter of 200 mm which gives the blades approximately 208 mm of width thus giving more surface area/aspect ratio of blade which provides certain air delivery should be minimum 210 m3/m (CMM) as per IS standard. For the size of blades with certain convex shapes easily meets the requirement of high air delivery. So that the air delivery can also be improved with more twist angle and lift angle of blades which put more load in the motor resulting in more power consumption by the ceiling fan which is not economical. There is need to develop a ceiling fan blade with less width of blade that gives the maximum air delivery, with twist angle and variable thickness as compared to the conventional ceiling fan to decrease load on fan motor.
OBJECTS OF THE INVENTION:
[006] The principal objective of the present invention is to provide a convex shaped blade for a ceiling fan which provides higher air spread in sweep of 1200mm.
[007] Another object of the present invention is to provide maximum air delivery about 239.32 m3/min (CMM) with diameter of rotating blade hub in range of 110 mm to 150 mm.
[008] Yet another object of present invention is to provide a convex shaped blade with optimized lift angle and twist angle for higher air delivery in sweep of 1200mm.
[009] Yet another object of the present invention is to provide a convex shaped blade with a winglet at tip end to reduce vortex.
[0010] Yet another object of the present invention is to increase performance of ceiling fan by reducing the power consumption while achieving the better Air Delivery and High Air Velocity.
[0011] Yet another object of the present invention is to provide a simple and cost-effective ceiling fan with convex shaped blades for higher air delivery and loss noise.
SUMMARY OF THE INVENTION:
[0012] The present subject matter relates to a ceiling fan with a convex shaped fan blade for higher air delivery at fan sweep size at a range of 1200 mm to 1350 mm, preferably 1200 mm. The convex shaped fan blade has a hub end towards rotor of the ceiling fan for connecting the convex shaped fan blade with the rotor and a tip end at distal end of the convex shaped fan blade. The convex shaped fan blade has a lift angle in range of 7o to 12o and a twist angle in range of 20o to 10o such that width of the fan blade is in range of 100 mm to 150 mm and length of fan blade is in range of 480 mm to 680 mm. Further, diameter of rotating blade hub is in range of 110 mm to 150 mm. The convex shaped fan blade is configured to provide the maximum air delivery about 239.32 m3/min (CMM).
[0013] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0015] Fig. 1 illustrates a pictorial view of a ceiling fan with a blade, in accordance with an embodiment of the present subject matter;
[0016] Fig. 2 and 3 illustrate lift angle and twist angle of the blade, in accordance with an embodiment of the present subject matter; and
[0017] Fig. 4 illustrates leading and trailing edge of the blade, in accordance with an embodiment of the present subject matter.
[0018] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0019] The present subject matter relates to a ceiling fan with a convex shaped fan blade for higher air delivery at fan sweep size at a range of 1200 mm to 1350 mm, preferably 1200 mm. The convex shaped fan blade has a hub end towards rotor of the ceiling fan for connecting the convex shaped fan blade with the rotor and a tip end at distal end of the convex shaped fan blade. The convex shaped fan blade has a lift angle in range of 7o to 12o and a twist angle in range of 20o to 10o such that width of the fan blade is in range of 100 mm to 150 mm and length of fan blade is in range of 480 mm to 680 mm. Further, diameter of rotating blade hub is in range of 110 mm to 150 mm. The convex shaped fan blade is configured to provide the maximum air delivery about 239.32 m3/min (CMM).
[0020] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be constructed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0021] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0022] Fig. 1 illustrates a pictorial view of a ceiling fan with a convex shaped blade, in accordance with an embodiment of the present subject matter. The ceiling fan assembly (or ceiling fan 200) 200 has a plurality of blades 202, a motor, a hanging downrod, and canopies. The canopies of the ceiling fan 200 and hanging downrod 102 are designed for matching with a motor profile to make the ceiling fan 200 more attractive. Further, the plurality of blades 202 is three in number. It can be more and less as per the requirement. The plurality of blades 202 is mounted to a rotating blade hub 201 and extending away from the rotating blade hub 201. The mounting can be done by a fastener i.e. screw. The plurality of blades 202 is mounted in such a manner that is looks smooth circumference at the rotating blade hub 201 such that diameter of the rotating blade hub 201 is in range of 110 mm to 150 mm.
[0023] Fig. 2 illustrates a lift angle and twist angle of the blade, in accordance with an embodiment of the present subject matter. The ceiling fan blade 202 has a convex/airfoil shaped profile for providing high air delivery at fan sweep size at a range of 1200 mm to 1350 mm, preferably 1200 mm, with less noise. The convex shaped ceiling fan blade 202 has a tip end 202b and a hub end 202a. The convex shaped ceiling fan blade 202 has a winglet 203 at the tip end 202b to reduce vortex. The winglet 203 maintains the air pressure at the tip end 202b. The convex shaped ceiling fan blade 202 is mounted to the hub end 202a. The tip end 202b rotates about a central axis of the motor during movement of the rotor. The winglet 203 allows smooth release of the high air pressure instead of immediate release of high air pressure from the surface of the convex shaped ceiling fan blade 202, due to which the convex shaped ceiling fan blade 202 has less air cutting noise as shown in figure 5.
[0024] As show in the figure 2, arrow X indicates horizontal direction or plane and arrow Y indicates vertical direction or plane. The tip end 202b rotates about central axis (Y axis) of the motor during movement of the rotor. The convex shaped ceiling fan blade 202 is thicker at the rotor end 202a tapering down to a thinner at the tip end 202b for providing high lift and low drag. The convex shaped ceiling fan blade 202 has a lift angle 201 in range 7o to 12o, with reference to horizontal axis X of the fan for higher air delivery. The lift angle 201 increases spread of air in the ceiling fan 300.
[0025] In accordance with an embodiment of the present subject matter relates to the convex shaped ceiling fan blade 202 has twist angle 204 in range of 20o to 10o along length of the convex shaped ceiling fan blade 202 from the hub end 202a to the tip end 202b, as shown in figure 3. The convex shaped ceiling fan blade 202 has curved profile along with length instead of flat profile as in existing fan blades. The curved profile of the convex shaped ceiling fan blade 202 has a leading edge 202c and a trailing edge 202d. The convex shaped ceiling fan blade 202 has a bottom concave curved surface and a top convex curved surface in between the leading edge 202c and the trailing edge 202d. The bottom concave curved surface between the leading edge 202c and the trailing edge 202d defines depth of the convex shaped ceiling fan blade 202. Further, width of the convex shaped blade 202 is in range of 100 mm to 150 mm and further, length of the convex shaped blade 202 is in range of 480 mm to 680 mm.
[0026] In accordance with the embodiment of the present subject matter relates to the convex shaped ceiling blade 202 has a leading edge 202c and a trailing edge 202d, as shown in figure 4. The thickness of the leading edge 202c is greater than thickness of the trailing edge 202d. The leading edge 202c is the edge where the convex shaped ceiling fan blade 202 starts compressing the air till the trailing edge 202d. The convex shaped ceiling fan blade 202 is curved along the length at range of 480 mm to 680 mm. The convex shaped ceiling fan blade 202 has continued twist angle running from the hub end 202a to the tip end 202b in Y axis. The twist angle is in range 20o to 10o from the hub end 202a to the tip end 202b.
[0027] In accordance with the embodiment of the present subject matter relates to the depth of the convex shaped ceiling fan blade 202 is in range 2 mm to 5 mm from the hub end 202a to the tip end 202b. The convex shaped ceiling fan blade 202 has length at range of 480 mm to 680 mm and fan sweep size at a range of 1200 mm to 1350 mm, preferably 1200 mm, as shown in figure 4. The convex shaped ceiling fan blade 202 is compounded polymer blade which is made in single mold. Further, the convex shaped ceiling fan blade 202 is painted with Polyurethane (PU) to increase shine and aesthetic appearance of the ceiling fan 300.
[0028] The present ceiling fan 300 with the convex shaped blade 202 provides higher air delivery of 239.32 m3/min (CMM) at full speed. Further, the present ceiling fan 300 has reduced the power consumption while achieving the better Air Delivery and High Air Velocity.
[0029] The present convex shaped fan blade unit provides better, more expeditious and economical results as compared with existing ceiling fans.

Criteria Present Blade
Air delivery (m3/min) 239.32
Air Speed ~1000 mm
RPM 300
Power Consumption (Watts) 62.48
Torque (N.m) 0.24
Stresses Equivalent Stress: 58 Mpa
Max. Principle Stress: 45 Mpa
Resonance Frequency 30.67 Hz

[0030] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.
,CLAIMS:We claim:
1. A ceiling fan assembly (200) comprising:
a rotating blade hub (201); and
a plurality of blades (202) mounted to the rotating blade hub (201) and extending away from the rotating blade hub (201),
characterized in that
wherein each blade from the plurality of blades (202) has a lift angle (201) in range of 7o to 12o and a twist angle (204) in range of 20o to 10o.
2. The ceiling fan assembly (100) as claimed in claim 1, wherein depth of each blade from the plurality of blades (202) has a leading edge (202c) and a trailing edge (202d), wherein thickness of the leading edge (202c) is greater than thickness of the trailing edge (202d).
3. The ceiling fan assembly (100) as claimed in claim 1, wherein each blade from the plurality of blades (202) is secured to the rotating blade hub (201) by at least one fastener.
4. The ceiling fan assembly (100) as claimed in claim 1, wherein the ceiling fan assembly (100) has sweep size in a range of 1200 mm to 1350 mm, preferably 1200 mm.
5. The ceiling fan assembly (100) as claimed in claim 1, wherein depth of each blade from the plurality of blades (202) is provided in a range of 2 mm to 5 mm.
6. The ceiling fan assembly (100) as claimed in claim 1, wherein a diameter of rotating blade hub (201) is provided in a range of 110 mm to 150 mm.
7. The ceiling fan assembly (100) as claimed in claim 1, wherein length of each blade from the plurality of blades (202) is provided in a range of 480 mm to 680 mm.
8. The ceiling fan blade (202) as claimed in claim 1, wherein width of each blade from the plurality of blades (202) is provided in a range of 100 mm to 150 mm.
9. The ceiling fan blade (202) as claimed in claim 1, wherein each blade from the plurality of blades (202) has lift angle (201) in a range of 7o to 12o.
10. A ceiling fan blade (202) for high air delivery in a ceiling fan (300), the ceiling fan blade (202) comprising:
a hub end (202a) towards rotor of the ceiling fan (300) for connecting the ceiling fan blade (202) with the rotor; and
a tip end (202b) at distal end of the ceiling fan blade (202);
wherein the ceiling fan blade (202) has a convex shaped profile which is thicker at the hub end (202a) tapering down to a thinner at the tip end (202b),
wherein the ceiling fan blade (202) has a lift angle (201) in range of 7o to 12o and a twist angle (204) in range 20o to 10o.
11. The ceiling fan blade (202) as claimed in claim 10, wherein the ceiling fan (300) has sweep size in a range of 1200 mm to 1350 mm, preferably 1200 mm.
12. The ceiling fan blade (202) as claimed in claim 10, wherein the ceiling fan blade (202) has a winglet (203) at the tip end (202b).
13. The ceiling fan blade (202) as claimed in claim 10, wherein length of ceiling fan blade (202) is provided in a range of 480 mm to 680 mm.
14. The ceiling fan blade (202) as claimed in claim 10, wherein width of the ceiling fan blade (202) is provided at a range of 100 mm to 150 mm.