FIELD OF INVENTION:
[001] The present subject matter described herein, in general, relates to field of electric fans, and in particularly relates to ceiling fan blades with twisted profile for providing increased airflow at low rotational speeds with lowest noise (dB level). In more particularly, a ceiling fan blades having specific and optimized blade angle, tilt angle and twist angle to deliver higher air delivery at low rotational speed, i.e., lower rotation per minute (RPM).
BACKGROUND AND PRIOR ART:
[002] Ceiling fans have been around for many years as a useful air circulator. The ceiling fans have stator, rotor, and a plurality of blades. The ceiling fans have a motor to rotate the plurality of blades about center of fan axis. The ceiling fans have the largest sweep and largest air flow for lowest power. The ceiling fans have a rotating motor with plurality of blades that is suspended on a fan rod hung from the roof. The popular blade style over the years is a flat planar rectangular blade that can have a slight tilt. Many of the flat ceiling fan blades have problems, such as vibrations and wobbling during use. Further, problem exist with the ceiling fan is excessive noise that is noticeable to persons in the vicinity of the fan blades. Several efforts have also been made to improve the air flow at low noise by varying the design of the fan blades. Reference may be made to the following-
[003] Publication No. WO02059484 (A1) discloses a fan blade having a substantially aerofoil shaped profile, comprising a first blade zone having a first continuous differentiated geometric angle of attack over the length of the first zone and a second blade zone, having a second continuous differentiated geometric angle of attack over the length of the second zone, which second blade is located near the tip of the fan blade, whereby the derivative of the differentiated geometric angle of attack of the first and second zone comprises a discontinuity at the transition of the first and the second zone.
[004] US Patent No. 7,413,410 discloses a ceiling fan blade that is twisted rather than flat and has a graduated dihedral. The dihedral is provided for a wider distribution of divergence of air in the space beneath the fan. The blade is demarked to have three sections which include a mounting section and two airflow sections. The two airflow sections are twisted with the rate of twist from the root end to the tip end being non-uniform. The twist or ratio of the degree increase in the angle of attack over each inch in length deceases from root end to the tip end.
[005] US Patent No. 6,659,721 discloses ceiling fan blades for maximizing air flow at operational speeds of up to approximately 200 revolutions per minute (rpm). The blades have a positive twist at the tip ends of approximately 5 degrees to approximately 10 degrees parallel to the ceiling. The root end of the blades closest to the motor can have a positive twist exceeding that of the tip end and can be approximately 20 to approximately 35 degrees parallel to the ceiling. The ceiling fans can have individual blade lengths of approximately 20 inches and overall spans of up to approximately 52 inches and up to approximately 54 inches.
[006] US Patent No. 6,039,541 discloses ceiling fan blades for low speed fan operation. The blades have a positive twist at the root motor portion of the blade and a slightly twisted rounded tip. The chord of the blades taper down from the root to the rounded tip, and have a tapered airfoil from the aft forward aft edge to the trailing edge. The airfoil has a combination of a rounded leading edge with sharp trailing edge, and a square leading edge and rounded trailing edge. The blades can be twenty inches in length and twenty-six inches in length, and be used in ceiling fans having two, three, four or more blades in a ceiling mount. The ceiling fan blades are optimized to operate in ceiling fans running at low speed ranges of approximately 50 to approximately 200 revolutions per minute(rpm) with an enhanced axial airflow which provide substantial energy savings and increased air flow over conventional flat planar ceiling fan blades.
[007] US Patent No. 6,733,241 discloses ceiling fan blades that have an angle attack that decreases from root end to tip end at higher rates of decrease nearer their tip ends than at their root ends.
[008] US Patent No. 6,719,532 discloses ceiling fan blades that have an angle attack that decreases from root end to tip end at higher rates of decrease nearer their tip ends than at their root ends. Air flow distribution is enhanced with at least a portion of the blades having a dihedral that continuously increases.
[009] Publication No. MX2009008468 (A) discloses a large industrial ceiling fan includes exceptionally long fan blades with blade tips that can be tilted upward to more broadly distribute the air. Such broad distribution might be particularly beneficial in cases where the fan is installed relatively low to avoid obstacles such as hanging lights, sprinkler heads and rafters. A low mounting position is possible, because the fan is suspended from a hanger of adjustable length. The fan includes several joints that are redundantly bolted and welded for safety. A continuous retaining ring provides additional safety. A resilient bushing enhances the flexibility of the fan blades and reduces strain where the fan blades connect to a central mounting hub. To more broadly distribute the airflow underneath the fan, each fan blade has a twisted geometry to provide an angle of attack that decreases from the root to the tip of the blade.
[0010] Indian Publication No. 1895/MUM/2015 discloses new design of mechanical ceiling fan is made with secondary blades, which are of 30% the total length of the primary blades. The tip end of the secondary blade would be 75% of total length at root end. Secondary blades would be attached to the primary blades with appropriate attachments and would make an angle of 120 degrees parallel to the ceiling facing upwards. Secondary blade would have its root end which is closest to primary blades twisted at an angle of 25 degrees parallel to the plane of the secondary blade and tip end which are farthest to the primary blades would have blades twisted at an angle of 5 degrees parallel to the plane of the secondary blade so as to cut the air and push downwards. The wing span of secondary blade would be approximately 15 centimetres and wing span of primary blade would be 50 centimetres. The root end length would be 10 centimetres and the tip end would be of 7.5 centimetres.
[0011] Thus, there is a need for fan blade which can deliver higher air at low speed and low noise by increase sweep minimally.
[0012] Hence the present invention aims to solve identified technical problem, i.e., higher air delivery at low speed and low noise with a minimal increase of sweep of the ceiling fan.
OBJECTS OF THE INVENTION:
[0013] The principal objective of the present invention is to provide a ceiling fan having a plurality of blades where each blade with specific and optimized blade angle, tilt angle, and twist angle, which result in higher air delivery at lower Rotation Per Minute (RPM) with lowest noise level with different and unique sweep of 1250 mm.
[0014] Another object of the present invention is to provide ceiling fan blades for higher air delivery at low speed.
[0015] Another object of the present invention is to provide ceiling fan blades for higher air spread with low noise.
[0016] Another object of the present invention is to provide an aesthetically different ceiling fan.
[0017] Another object of the present invention is to provide ceiling fan blades that generate less vibrations and wobbling during use.
[0018] Another object of the present invention is to provide ceiling fan blades that save electricity.
[0019] Yet another object of the present invention is to provide a ceiling fan with unique sweep of 1250 mm.
SUMMARY OF THE INVENTION:
[0020] The present subject matter relates to a ceiling fan to provide high air delivery at low rotational speed with low noise with novel sweep of 1250mm and higher spread radius of 1000mm. The ceiling fan has a rotating motor and a plurality of fan blades. Each fan blade from the plurality of fan blades has a tip end and a hub end. The fan blade is coupled with the rotating motor of the ceiling fan through the hub end to receive rotational force. Each fan blade from the plurality of fan blades has a different optimized blade angle at a different distance from center axis of the ceiling fan along length of the fan blade, a lift angle, and a twist angle. Further, the blades have width of 157 mm at tip end and 199 mm at hub end, which make the ceiling fan as novel one to generate the higher air delivery with lowest noise with better air spread of 1000mm (radius) as per air delivery test standard.
[0021] In another embodiment of the present subject matter describes a novel fan blades fan blade for ceiling fan to provide high air delivery at low rotational speed with low noise. The fan blade has a tip end and a hub end. The fan blade is coupled with a rotating motor of the ceiling at hub end to receive rotational force. The fan blade has different blade angle of approximately 5.77o, 10.24o, 12.25o and 19.276o degree at different distance 155mm, 195mm, 235mm, and 540mm from center axis of the ceiling fan along length of the fan blade, respectively. Further, the fan blade has a positive twist angle of approximately 19.3 degrees at about 100 mm from tip end. The hub end has a positive lift angle that of the tip end with approximately 4.8 degree a lift angle. The fan blade has length of 571mm which gives a fan sweep of approximately 1250mm. The present fan blades are made of injection molded plastic.
[0022] 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
[0023] 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:
[0024] Fig. 1 illustrates fan blades with optimized angle at the different distance from center axis, in accordance with the present subject matter;
[0025] Fig. 2A illustrates cross section A:A’ as shown in fig. 1, cross section AA’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter;
[0026] Fig. 2B illustrates cross section B:B’ as shown in fig. 1, cross section B:B’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter;
[0027] Fig. 2C illustrates cross section C:C’ as shown in fig. 1, cross section C: C’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter;
[0028] Fig. 2D illustrates cross section D:D’ as shown in fig. 1, cross section D: D’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter;
[0029] Fig. 3A illustrates lift angle of the fan blades, in accordance with the present subject matter;
[0030] Fig. 3B illustrates combined twist angle of the fan blades, in accordance with the present subject matter;
[0031] Fig. 4 illustrates another view of the fan with twisted blades, in accordance with the present subject matter; and
[0032] Fig. 5 illustrates air quantity graph in comparison with 1200mm sweep Model, in accordance with the present subject matter.
[0033] 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:
[0034] The present subject matter relates to a ceiling fan to provide high air delivery at low rotational speed with low noise with novel sweep of 1250mm and higher spread radius of 1000mm. The ceiling fan has a rotating motor and a plurality of fan blades. Each fan blade from the plurality of fan blades has a tip end and a hub end. The fan blade is coupled with the rotating motor of the ceiling fan through the hub end to receive rotational force. Each fan blade from the plurality of fan blades has a different optimized blade angle at a different distance from center axis of the ceiling fan along length of the fan blade, a lift angle, and a twist angle. Further, the blades have width of 157 mm at tip end and 199 mm at hub end, which make the ceiling fan as novel one to generate the higher air delivery with lowest noise with better air spread of 1000mm (radius) as per air delivery test standard.
[0035] In another embodiment of the present subject matter describes a novel fan blades fan blade for ceiling fan to provide high air delivery at low rotational speed with low noise. The fan blade has a tip end and a hub end. The fan blade is coupled with a rotating motor of the ceiling at hub end to receive rotational force. The fan blade has different blade angle of approximately 5.77o, 10.24o, 12.25o and 19.276o degree at different distance 155mm, 195mm, 235mm, and 540mm from center axis of the ceiling fan along length of the fan blade, respectively. Further, the fan blade has a positive twist angle of approximately 19.3 degrees at about 100 mm from tip end. The hub end has a positive lift angle that of the tip end with approximately 4.8 degree a lift angle. The fan blade has length of 571mm which gives a fan sweep of approximately 1250mm. The present fan blades are made of injection molded plastic.
[0036] 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 construed 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.
[0037] 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.
[0038] The present subject matter provides a ceiling fan with a plurality of blades each one with specific and optimized blade angle, Tilt angle and Twist angle, which result in higher air delivery at lower RPM with lowest noise level with different and unique sweep of 1250mm which results in higher air spread of radius 1000mm. The fan is delivering better performance than any of the similar kind of fan. The efficiency of fan is calculated on the basis on air delivery and the noise it produces. The present invention focuses on improving the comfort factor. Comfort factor is directly related to the air delivered by the fan. Comfort factor is inversely proportional to the noise it produces during the operation. In the fan according to the present subject matter, shank is integrated to the blade to reduce the number of components in a fan. Further detailed constructions and components are illustrated in the below mentioned figures.
[0039] Fig. 1 illustrates fan blades with optimized angle at the different distance from center axis, in accordance with the present subject matter. The ceiling fan has a plurality of fan blades. Further, the number of fan blades can be 3 to 6 or more as per requirements. Generally, a ceiling fan has three fan blades, therefore, the present subject matter is explained in reference to a ceiling fan having three fan blades. Further, the present fan blades can be implemented in any ceiling fan. The present subject matter relates to optimize ceiling fan blades, which provide the higher air delivery at operational speeds of ~ 220-230 revolutions per minute (rpm). The fan blades 101, 102, 103 (collectively referred as 101) have a tip end 101a and a hub end 101b. The hub end 101b is coupled with a rotating motor of the ceiling fan to receive a rotational force to rotate the blade. The fan blade 101 has a positive twist angle 301 at 100 mm distance from tip ends 101a is of approximately 19.3 degrees as shown in figure 3A. The hub ends 101b of the blades closest to the rotating motor of the ceiling fan have a positive lift angle 302 that of the tip end with approximately 4.8 degree.

[0040] The ceiling fan 400, as shown in the figure 4, has individual blade length of 571 mm which gives the ceiling fan a unique fan sweep of approximately 1250 mm. Further, the present optimized blades are made of injection molded plastic. The blades 101 have width of 157 mm at the tip end 101a and 199 mm at the hub end 101b. The width of the blade at the tip end and the hub end 101b makes the ceiling fan as unique one to generate the higher air delivery with lowest noise with better air spread of 1000mm (radius) as per air delivery test standard.
[0041] Fig. 2A illustrates cross section A:A’ as shown in fig. 1, cross section AA’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter. The cross section AA’ illustrates the cross section of fan blade 101 at 155mm distance from the center of the fan axis 104. The section of the blade upto 155mm from the hub end 101b has an optimized blade angle 201 of approximately 5.77 degrees.
[0042] Fig. 2B illustrates cross section B:B’ as shown in fig. 1, cross section B:B’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter. The cross section BB’ illustrates the cross section of fan blade 101 at 195mm distance from the center of the fan axis 104. The section of the blade upto 195mm from the hub end 101b has an optimized blade angle 202 of approximately 10.24 degrees.
[0043] Fig. 2C illustrates cross section C:C’ as shown in fig. 1, cross section C: C’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter. The cross section CC’ illustrates the cross section of fan blade 101 at 235mm distance from the center of the fan axis 104. The section of the blade upto 235mm from the hub end 101b has an optimized blade angle 203 of approximately 12.25 degrees.
[0044] Fig. 2D illustrates cross section D:D’ as shown in fig. 1, cross section D: D’ illustrates different angle at different cross section from fan axis, in accordance with the present subject matter. The cross section DD’ illustrates the cross section of fan blade 101 at 540mm distance from the center of the fan axis 104. The section of the blade upto 540mm from the hub end 101b has an optimized blade angle 204 of approximately 19.276 degrees. The fan blade 101 with different blade angle at different distance makes the ceiling fan novel to deliver higher air with better air spread of 1000mm radius as per air delivery test standard.
[0045] Fig. 3A illustrates lift angle of the fan blades, in accordance with the present subject matter. The lift angle 301 of the fan blade is approximately 4.8 degrees.
[0046] Fig. 3B illustrates combined twist angle of the fan blades, in accordance with the present subject matter. The combined twist angle 302 of the fan blade is of approximately 19.3 degrees.
[0047] Fig. 4 illustrates another view of the fan with twisted blades, in accordance with the present subject matter. The ceiling fan 400 has fan blades as per the present subject matter as explained above. The ceiling fan 400 has fan blades with twisted profiler for providing increased air flow at low rotational speeds with lowest noise ratio.
Fig. 5 illustrates air quantity graph in comparison with 1200mm sweep Model, in accordance with the present subject matter. As per air delivery test standard with the optimized blade design able to achieve 160 mm of air spread (320 mm in diameter) more with just 50mm increase in sweep.
[0048]
S. No.: Parameters Present Ceiling fan Existing Silent fan Normal fan Remarks
1 Fan Speed (RPM) 220-230 295 More than 350 Lower RPM; better with higher performance
2 Air delivery (CMM) 260-285 240 220-230 Higher the better
3 Noise lever (dB) 47-50 51 57 Lower is better
4 Sweep Dia (mm) 1250 1200 1200 Higher is better
5 Average Radius of air Delivery (mm) 1000 840 840 Higher is better,
Higher air spread

[0049] The present subject matter, i.e., fan blades and the ceiling fan having the said fan blades is better than any other existing fan blade. The present ceiling fan having the novel fan blades has several advantages which are listed below:
[0050] High air delivery in the ceiling fan industry
[0051] Low noise level in the ceiling fan industry
[0052] New sweep fan introduction of 1250mm in the ceiling fan industry
[0053] Better air spread
[0054] 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.

We Claim:
1. A ceiling fan (400) to provide high air delivery at low rotational speed with low noise, the ceiling fan (400) comprising:
a rotating motor;
a plurality of fan blades (101) having a tip end (101a) and a hub end (101b), the plurality of fan blades (101) is coupled with the rotating motor through the hub end (101b) to receive rotational force,
wherein each fan blade (101) from the plurality of fan blades (101) has a different optimized blade angle (201, 202, 203, 204) at a different distance from center axis (104) of the ceiling fan along length of the fan blade (101), a lift angle (301), and a combined twist angle (302).

2. The ceiling fan (400) as claimed in claim 1, wherein the each fan blade (101) from the plurality of fan blades (101) has a positive twist angle (302) approximately 19.3 degrees at about 100 mm from the tip end (101a) of the fan blade (101, 300).

3. The ceiling fan (400) as claimed in claim 1, wherein the hub end (101b) of each fan blade (101) from the plurality of fan blades (101) has a positive lift angle (301) that of the tip end (101a) with approximately 4.8 degree.

4. The ceiling fan (400) as claimed in claim 1, wherein the each fan blade (101) from the plurality of fan blades (101) has width of 157 mm at the tip end (101a) and 199 mm at the hub end (101b) to generate higher air delivery with lowest noise with better air spread of 1000mm (radius).

5. The ceiling fan (400) as claimed in claim 1, wherein the each fan blade (101) from the plurality of fan blades (101) has blade length of 571 mm with fan sweep of approximately 1250 mm.

6. The ceiling fan (400) as claimed in claim 1, wherein the each fan blade (101) from the plurality of fan blades (101) is made of injection molded plastic.

7. The ceiling fan (400) as claimed in claim 1, wherein the each fan blade (101) from the plurality of fan blades (101) at distance 155mm, 195mm, 235mm, and 540mm from the center axis of fan have blade angle (201, 202, 203, 204) of approximately 5.77o, 10.24o, 12.25o and 19.276o degree respectively.

8. The ceiling fan (400) as claimed in claim 1, wherein the ceiling fan (400) has sweep of 1250mm.

9. The ceiling fan (400) as claimed in claim 1, wherein the ceiling fan (400) delivers higher air of 270-285 CMM at operational speeds of ~ 220-230 revolutions per minute (RPM).

10. A fan blade (101) for ceiling fan (400) to provide high air delivery at low rotational speed with low noise, the fan blade (101) comprising:
a tip end (101a) and a hub end (101b), wherein the hub end (101b) is coupled with a rotating motor of the ceiling fan (400) to receive rotational force,
wherein the fan blade (101) has different blade angle (201, 202, 203, 204) of approximately 5.77o, 10.24o, 12.25o and 19.276o degree at different distance 155mm, 195mm, 235mm, and 540mm from center axis (104) of the ceiling fan (400) along length of the fan blade (101), respectively;
wherein the fan blade (101) has a positive twist angle (302) of approximately 19.3 degrees at about 100 mm from the tip end (101a); and
wherein the hub end (101b) has a positive lift angle (301) that of the tip end with approximately 4.8 degree.