Patent Publication Number: US-2018045203-A1

Title: Fan

Description:
BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates to a fan and more particularly to one taking advantage of the Coanda effect to increase the overall flow rate of its output airflow. 
     Description of Related Art 
     Fans typically have blades or vanes, which nevertheless hinder passage of light, are difficult to clean, compromise the portability of fans, and take up considerable space when the fans are used in vehicles. 
     A bladeless fan is disclosed in U.S. Pat. No. 2,488,467. Lacking a Coanda surface, however, this bladeless fan does not produce the Coanda effect, meaning the fan cannot entrain an airflow from the surroundings to increase the overall flow rate of the output airflow. In addition, known bladeless fans do not have a diffusion surface for guiding an airflow in a predetermined direction and therefore fail to guide an air current effectively. 
     As to bladeless fans with a Coanda surface, it is generally required to increase the volume of the nozzle if it is desired to enlarge the Coanda surface without increasing the nozzle openings. This has been a problem to be solved in the fan industry. 
     BRIEF SUMMARY OF THE INVENTION 
     The objective of the present invention is to solve the aforesaid problem that, in order to enlarge the Coanda surface of a conventional bladeless fan without increasing the nozzle openings, the nozzle of the fan must be increased in volume. 
     To achieve the objective, the present invention provide a fan, comprising: a base; and a nozzle mounted on the base and having: a nozzle airflow inlet located at the nozzle and configured as an opening for receiving an airflow ejected from the base; a first wall; a second wall arranged generally parallel to the first wall; a first wall end located at an end of the generally parallelly arranged first and second walls; a second wall end located at an opposite end of the generally parallelly arranged first and second walls; first wall edges, which are wall edges of the generally parallelly arranged first and second walls that jointly extend to a side; second wall edges, which are wall edges of the generally parallelly arranged first and second walls that jointly extend to an opposite side; a partition wall located between the first wall and the second wall; a first nozzle airflow outlet located between the first wall edge of the second wall and the partition wall and configured as an opening for ejecting an airflow; and a second nozzle airflow outlet located between the first wall edge of the first wall and the partition wall and configured as an opening for ejecting an airflow; wherein the first wall edge of the second wall is folded in an annularly curved or bent manner to form a first Coanda surface adjacent to the first nozzle airflow outlet and capable of producing the Coanda effect, and the partition wall is folded either inward in an opposite direction of an airflow direction or outward in the airflow direction in an annularly curved or bent manner to form a closed wall, the closed wall forming a second Coanda surface adjacent to the second nozzle airflow outlet and capable of producing the Coanda effect. 
     Further, the second wall edges form a closed side for preventing an outgoing airflow or an opening that allows passage of an airflow. 
     Further, the second wall is folded inward in the opposite direction of the airflow direction in an annularly curved or bent manner to form a closed wall for preventing an ingoing airflow, or the second wall is folded outward in the airflow direction in an annularly curved or bent manner to form the first Coanda surface adjacent to the first nozzle airflow outlet and capable of producing the Coanda effect. 
     Further, the second wall end is joined with the first wall end to form an annular hollow portion, and the annular hollow portion encircles a central hollow portion that allows passage of light and an airflow. 
     Further, the second wall end has a second tightly closing wall for preventing passage of an airflow, and the first wall end has a first tightly closing wall for preventing passage of an airflow. 
     Further, there is one said nozzle airflow inlet, provided at the first wall or the second wall; or there are a plurality of said nozzle airflow inlets, provided at the first wall or the second wall. 
     Further, the second nozzle airflow outlet formed between the first wall edge of the first wall and the partition wall is a tapered slit, and the first nozzle airflow outlet formed between the first wall edge of the second wall and the partition wall is a tapered slit. 
     Further, the second nozzle airflow outlet formed between the first wall edge of the first wall and the partition wall is a rectangular slit, and the first nozzle airflow outlet formed between the first wall edge of the second wall and the partition wall is a rectangular slit. 
     Further, the first nozzle airflow outlet or the second nozzle airflow outlet is divided into a plurality of spaces by a plurality of partition plates. 
     Further, there are a plurality of said partition walls so as to form a plurality of said second Coanda surfaces as well as a plurality of said second nozzle airflow outlets. 
     Further, the second wall has a diffusion surface for guiding an airflow in a predetermined direction. 
     Further, the second wall edge of the first wall is folded in an annularly curved or bent manner to form a third tightly closing wall, and the third tightly closing wall is adhesively attached to the second wall to prevent an outgoing airflow. 
     Further, the second wall edge of the second wall is folded in an annularly curved or bent manner to form a third tightly closing wall, and the third tightly closing wall is adhesively attached to the first wall to prevent an outgoing airflow. 
     Further, the nozzle includes a third tightly closing wall, and the third tightly closing wall has two sides adhesively attached to the first wall and the second wall respectively to prevent an outgoing airflow. 
     Further, the base has an internal fan for taking in air and ejecting an airflow, a base airflow inlet for taking in air, and a base airflow outlet for ejecting an airflow. 
     Further, the internal fan is a forced-draft fan, a planar fan, or a jet turbine-blade fan. 
     Further, the internal fan is a plurality of parallel-connected or series-connected planar fans. 
     Further, the base comprises a filter screen provided therein. 
     The present invention solves the problem that the Coanda surface of a conventional bladeless fan cannot be enlarged without increasing the volume of the nozzle, if the areas of the nozzle openings are to remain unchanged. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a partial schematic view of the first example of a nozzle in the present invention. 
         FIG. 2  shows a partial schematic view of the second example of the nozzle in the present invention. 
         FIG. 3  shows a front schematic view of the first embodiment. 
         FIG. 4  shows a sectional schematic view of the first embodiment. 
         FIG. 5  shows an exploded schematic view of the second embodiment. 
         FIG. 6  shows a sectional schematic view of the second embodiment. 
         FIG. 7  shows an external perspective view of the third embodiment. 
         FIG. 8  shows a sectional schematic view of the third embodiment. 
         FIG. 9  shows an external perspective view of the forth embodiment. 
         FIG. 10  shows a sectional schematic view of the forth embodiment. 
         FIG. 11  shows a schematic view of an example of a forced-draft fan in the present invention. 
         FIG. 12  shows a schematic view of an example of a planar fan in the present invention. 
         FIG. 13  shows a schematic view of an example of a jet-turbine fan in the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT OF THE INVENTION 
     The nozzle referred to in the present invention is described below with reference to two different embodiments. 
     Please refer to  FIG. 1  for a partial schematic view of the first example of the nozzle in the present invention. 
     As shown in  FIG. 1 , the nozzle  12 , to be mounted on a base to increase the range of airflow input, has a nozzle airflow inlet  121 , a first wall  122 , a second wall  123 , a first wall end  124 , a second wall end  125 , first wall edges  126 , second wall edges  127 , a first nozzle airflow outlet  128   a , a second nozzle airflow outlet  128   b , a diffusion surface  129 , a third tightly closing wall  133 , and a partition wall  130 . 
     Located at the nozzle  12 , the nozzle airflow inlet  121  is an opening for receiving the airflow ejected from the base. There may be a single nozzle airflow inlet  121  provided at the first wall  122  or the second wall  123 . There may alternatively be a plurality of nozzle airflow inlets  121  provided at the first wall  122  or the second wall  123 . The second wall  123  is arranged generally parallel to the first wall  122 . The first wall end  124  is located at one end of the generally parallelly arranged first and second walls  122  and  123 . The second wall end  125  is located at the opposite end of the generally parallelly arranged first and second walls  122  and  123 . The first wall edges  126  are wall edges of the generally parallelly arranged first and second walls  122  and  123  that jointly extend to one side. The second wall edges  127  are wall edges of the generally parallelly arranged first and second walls  122  and  123  that jointly extend to the opposite side. In this embodiment, the second wall edges  127  form a closed side for preventing an outgoing airflow. In another preferred embodiment, the second wall edge  127  of the first wall  122  is folded in an annularly curved or bent manner to form a third tightly closing wall  133 , and the third tightly closing wall  133  is adhesively attached to the second wall  123  to prevent an outgoing airflow. In yet another preferred embodiment, the second wall edge  127  of the second wall  123  is folded in an annularly curved or bent manner to form a third tightly closing wall  133 , and this third tightly closing wall  133  is adhesively attached to the first wall  122  to prevent an outgoing airflow. In still another preferred embodiment, the nozzle  12  includes a third tightly closing wall  133  with two opposite sides adhesively attached to the first wall  122  and the second wall  123  respectively to prevent an outgoing airflow. The partition wall  130  lies between the first wall  122  and the second wall  123 . The first nozzle airflow outlet  128   a  is located between the first wall edge  126  of the second wall  123  and the partition wall  130  and is a tapered opening, or tapered slit, configured for ejecting an airflow. In another preferred embodiment, the first nozzle airflow outlet  128   a  is a rectangular opening, or rectangular slit, instead. The second nozzle airflow outlet  128   b  is located between the first wall edge  126  of the first wall  122  and the partition wall  130  and is a tapered opening, or tapered slit, configured for ejecting an airflow. In another preferred embodiment, the second nozzle airflow outlet  128   b  is a rectangular opening, or rectangular slit, instead. The diffusion surface  129  is formed by the second wall  123  and is configured for guiding an airflow in a predetermined direction. 
     The first wall edge  126  of the second wall  123  is folded in an annularly curved or bent manner to form a first Coanda surface  134   a  adjacent to the first nozzle airflow outlet  128   a . The first Coanda surface  134   a  not only can produce the Coanda effect to increase the overall flow rate of the output airflow, but also helps reduce the overall volume of the nozzle. The partition wall  130  is folded inward (i.e., in the opposite direction of the airflow direction) in an annularly curved or bent manner to form a closed wall for preventing an ingoing airflow, wherein the closed wall forms a second Coanda surface  134   b  adjacent to the second nozzle airflow outlet  128   b  and capable of producing the Coanda effect to increase the overall flow rate of the output airflow. Thus, without having to change the areas of the nozzle openings or the volume of the nozzle, the Coanda surfaces can be enlarged to enhance the Coanda effect and thereby raise the overall flow rate of the output airflow. In another preferred embodiment, the partition wall  130  is folded outward (i.e., in the same direction as the airflow direction) in an annularly curved or bent manner to form the second Coanda surface  134   b.    
     Please refer to  FIG. 2  for a partial schematic view of the second example of the nozzle in the present invention. 
     As shown in  FIG. 2 , the nozzle  22 , to be mounted on a base to increase the range of airflow input, has a nozzle airflow inlet  221 , a first wall  222 , a second wall  223 , a first wall end  224 , a second wall end  225 , first wall edges  226 , second wall edges  227 , a first nozzle airflow outlet  228   a , a second nozzle airflow outlet  228   b , a diffusion surface  229 , a third tightly closing wall  233 , and a partition wall  230 . 
     Located at the nozzle  22 , the nozzle airflow inlet  221  is an opening for receiving the airflow ejected from the base. The second wall  223  is arranged generally parallel to the first wall  222 . The first wall end  224  is located at one end of the generally parallelly arranged first and second walls  222  and  223 . The second wall end  225  is located at the opposite end of the generally parallelly arranged first and second walls  222  and  223 . The first wall edges  226  are wall edges of the generally parallelly arranged first and second walls  222  and  223  that jointly extend to one side. The second wall edges  227  are wall edges of the generally parallelly arranged first and second walls  222  and  223  that jointly extend to the opposite side. The second wall edges  227  form a closed side for preventing an outgoing airflow. The partition wall  230  lies between the first wall  222  and the second wall  223 . The first nozzle airflow outlet  228   a  is located between the first wall edge  226  of the second wall  223  and the partition wall  230  and is a tapered opening, or tapered slit, configured for ejecting an airflow. The second nozzle airflow outlet  228   b  is located between the first wall edge  226  of the first wall  222  and the partition wall  230  and is a tapered opening, or tapered slit, configured for ejecting an airflow. The diffusion surface  229  is formed by the second wall  223  and is configured for guiding an airflow in a predetermined direction. 
     The first wall edge  226  of the second wall  223  is folded inward (i.e., in the opposite direction of the airflow direction) in an annularly curved or bent manner to form a closed wall for preventing an ingoing airflow, wherein the closed wall forms a first Coanda surface  234   a  adjacent to the first nozzle airflow outlet  228   a . The first Coanda surface  234   a  not only can produce the Coanda effect to increase the overall flow rate of the output airflow, but also helps reduce the overall volume of the nozzle. In another preferred embodiment, the second wall  223  is folded outward (i.e., in the airflow direction) in an annularly curved or bent manner to form the first Coanda surface (not shown). The partition wall  230  is folded inward (i.e., in the opposite direction of the airflow direction) in an annularly curved or bent manner to form a closed wall for preventing an ingoing airflow, wherein the closed wall forms a second Coanda surface  234   b  adjacent to the second nozzle airflow outlet  228   b  and capable of producing the Coanda effect to increase the overall flow rate of the output airflow. Thus, without having to change the areas of the nozzle openings or the volume of the nozzle, the Coanda surfaces can be enlarged to enhance the Coanda effect and thereby raise the overall flow rate of the output airflow. In another preferred embodiment, the partition wall  230  is folded outward (i.e., in the airflow direction) in an annularly curved or bent manner to form a closed wall with the second Coanda surface (not shown). 
     Please refer to  FIG. 3  and  FIG. 4  for a front view and a sectional view of the first embodiment of the present invention respectively. 
     As shown in  FIG. 3  and  FIG. 4 , the fan  30  in the first embodiment of the present invention includes a base  31  and a nozzle  32 . 
     The base  31  has: an internal fan  311  for taking in air and ejecting an airflow, a base airflow inlet  312  for taking in air, and a base airflow outlet  313  for ejecting an airflow. 
     The nozzle  32  is mounted on the base  31 . Most of the central portion of the nozzle  32  is hollow to allow passage of light and an airflow and to increase the range of airflow input. The nozzle  32  has: a nozzle airflow inlet  321 , which is an opening located at the nozzle  32  and configured for receiving the airflow ejected from the base airflow outlet  313 ; a first wall  322 ; a second wall  323  arranged generally parallel to the first wall  322 , wherein in this embodiment, a second wall end is joined with a first wall end to form an annular hollow portion that encircles the light- and airflow-penetrable central hollow portion of the nozzle; first wall edges  326 , which are wall edges of the generally parallelly arranged first and second walls  322  and  323  that jointly extend to one side; second wall edges  327 , which are wall edges of the generally parallelly arranged first and second walls  322  and  323  that jointly extend to the opposite side, wherein the second wall edges  327  form a closed side for preventing an outgoing airflow; a partition wall  330  lying between the first wall  322  and the second wall  323 ; a first nozzle airflow outlet  328   a  located between the first wall edge  326  of the second wall  323  and the partition wall  330 ; a second nozzle airflow outlet  328   b  located between the first wall edge  326  of the first wall  322  and the partition wall  330 , wherein in a preferred embodiment, the first nozzle airflow outlet  328   a  or the second nozzle airflow outlet  328   b  is divided by a plurality of partition plates  335  into a plurality of spaces, and the partition wall  330  is supported by the partition plates  335 ; and a diffusion surface  329  for guiding an airflow in a predetermined direction. The first wall edge  326  of the second wall  323  is folded in an annularly curved or bent manner to form a first Coanda surface  334   a  adjacent to the first nozzle airflow outlet  328   a  and capable of producing the Coanda effect to increase the overall flow rate of the output airflow. The partition wall  330  between the first wall  322  and the second wall  323  is folded either inward (i.e., in the opposite direction of the airflow direction) or outward (i.e., in the airflow direction) in an annularly curved or bent manner to form a closed wall, wherein the closed wall forms a second Coanda surface  334   b  adjacent to the second nozzle airflow outlet  328   b  and capable of producing the Coanda effect. The diffusion surface  329  guides the output airflow in the predetermined direction. 
     Please refer to  FIG. 5  and  FIG. 6  for an exploded schematic view and a sectional view of the second embodiment of the present invention respectively. 
     As shown in  FIG. 5  and  FIG. 6 , the fan  40  in the second embodiment of the present invention includes a base  41  and a nozzle  42 . 
     The base  41  has: an internal fan  411  for taking in air and ejecting an airflow, a base airflow inlet  412  for taking in air, and a base airflow outlet  413  for ejecting an airflow. 
     The nozzle  42  is mounted on the base  41 . Most of the central portion of the nozzle  42  is hollow to allow passage of light and an airflow and to increase the range of airflow input. The nozzle  42  has: a nozzle airflow inlet  421 , which is an opening located at the nozzle  42  and configured for receiving the airflow ejected from the base airflow outlet  413 ; a first wall  422 ; a second wall  423  arranged generally parallel to the first wall  422 ; a first wall end  424  located at one end of the generally parallelly arranged first and second walls  422  and  423 ; a second wall end  425  located at the opposite end of the generally parallelly arranged first and second walls  422  and  423 , wherein in this embodiment, the second wall end  425  has a second tightly closing wall  4251  for preventing passage of an airflow, and the first wall end  424  has a first tightly closing wall  4241  for preventing passage of an airflow; first wall edges  426 , which are wall edges of the generally parallelly arranged first and second walls  422  and  423  that jointly extend to one side; second wall edges  427 , which are wall edges of the generally parallelly arranged first and second walls  422  and  423  that jointly extend to the opposite side, wherein in this embodiment, the second wall edges  427  form an opening through which an airflow can pass; a partition wall  430  lying between the first wall  422  and the second wall  423 ; a first nozzle airflow outlet  428   a  located between the first wall edge  426  of the second wall  423  and the partition wall  430 ; a second nozzle airflow outlet  428   b  located between the first wall edge  426  of the first wall  422  and the partition wall  430 ; and a diffusion surface  429  for guiding an airflow in a predetermined direction. The first wall edge  426  of the second wall  423  is folded in an annularly curved or bent manner to form a first Coanda surface  434   a  adjacent to the first nozzle airflow outlet  428   a  and capable of producing the Coanda effect to increase the overall flow rate of the output airflow. The partition wall  430  between the first wall  422  and the second wall  423  is folded either inward (i.e., in the opposite direction of the airflow direction) or outward (i.e., in the airflow direction) in an annularly curved or bent manner to form a closed wall, wherein the closed wall forms a second Coanda surface  434   b  adjacent to the second nozzle airflow outlet  428   b  and capable of producing the Coanda effect. The diffusion surface  429  guides the output airflow in the predetermined direction. 
     Please refer to  FIG. 7  and  FIG. 8  for an external perspective view and a sectional view of the third embodiment of the present invention respectively. 
     As shown in  FIG. 7  and  FIG. 8 , the fan  50  in the third embodiment of the present invention includes a base  51  and a nozzle  52 . 
     The base  51  has: a plurality of internal fans  511  for taking in air and ejecting airflows, wherein the internal fans  511  are planar fans connected in parallel to each other; a base airflow inlet  512  for taking in air; a base airflow outlet  513  for ejecting an airflow; and a filter screen  514  provided in the base  51  to filter the air flowing into the base through the base airflow inlet  512 . 
     Mounted on the base  51  to increase the range of airflow input, the nozzle  52  has: a nozzle airflow inlet  521 , which is an opening located at the nozzle  52  and configured for receiving the airflow ejected from the base airflow outlet  513 ; a first wall  522 ; a second wall  523  arranged generally parallel to the first wall  522 ; a first wall end  524  located at one end of the generally parallelly arranged first and second walls  522  and  523 ; a second wall end  525  located at the opposite end of the generally parallelly arranged first and second walls  522  and  523 , wherein in this embodiment, the second wall end  525  has a second tightly closing wall (not shown) for preventing passage of an airflow, and the first wall end  524  has a first tightly closing wall  5241  for preventing passage of an airflow; first wall edges  526 , which are wall edges of the generally parallelly arranged first and second walls  522  and  523  that jointly extend to one side; second wall edges  527 , which are wall edges of the generally parallelly arranged first and second walls  522  and  523  that jointly extend to the opposite side, wherein the second wall edges  527  form a closed side for preventing an outgoing airflow; a partition wall  530  lying between the first wall  522  and the second wall  523 ; a first nozzle airflow outlet  528   a  located between the first wall edge  526  of the second wall  523  and the partition wall  530 ; a second nozzle airflow outlet  528   b  located between the first wall edge  526  of the first wall  522  and the partition wall  530 ; and a diffusion surface  529  for guiding an airflow in a predetermined direction. The first wall edge  526  of the second wall  523  is folded in an annularly curved or bent manner to form a first Coanda surface  534   a  adjacent to the first nozzle airflow outlet  528   a  and capable of producing the Coanda effect to increase the overall flow rate of the output airflow. The partition wall  530  between the first wall  522  and the second wall  523  is folded in an annularly curved or bent manner to form a second Coanda surface  534   b  adjacent to the second nozzle airflow outlet  528   b  and capable of producing the Coanda effect. The diffusion surface  529  guides the output airflow in the predetermined direction. In a preferred embodiment, the partition wall  530  is folded either inward (i.e., in the opposite direction of the airflow direction) or outward (i.e., in the airflow direction) in an annularly curved or bent manner to form a closed wall, which in turn forms a plurality of second Coanda surfaces  534   b  as well as a plurality of second nozzle airflow outlets  528   b.    
     Please refer to  FIG. 9  and  FIG. 10  for a external perspective view and a sectional view of the fourth embodiment of the present invention respectively. 
     As shown in  FIG. 9  and  FIG. 10 , the fan  60  in the fourth embodiment of the present invention includes a base  61  and a plurality of nozzles  62 . 
     The base  61  has: a plurality of internal fans  611  for taking in air and ejecting airflows, wherein the internal fans  611  are planar fans connected in series to each other; a base airflow inlet  612  for taking in air; and a base airflow outlet  613  for ejecting an airflow. 
     The nozzles  62  are mounted on the base  61 . Most of the central portion of each nozzle  62  is hollow to allow passage of light and an airflow and to increase the range of airflow input. Each nozzle  62  has: a nozzle airflow inlet  621 , which is an opening located at the nozzle  62  and configured for receiving the airflow ejected from the base airflow outlet  613 ; a first wall  622 ; a second wall  623  arranged generally parallel to the first wall  622 , wherein in this embodiment, a second wall end is joined with a first wall end to form an annular hollow portion that encircles the light- and airflow-penetrable central hollow portion of the nozzle; first wall edges  626 , which are wall edges of the generally parallelly arranged first and second walls  622  and  623  that jointly extend to one side; second wall edges  627 , which are wall edges of the generally parallelly arranged first and second walls  622  and  623  that jointly extend to the opposite side, wherein the second wall edges  627  form a closed side for preventing an outgoing airflow; a partition wall  630  lying between the first wall  622  and the second wall  623 ; a first nozzle airflow outlet  628   a  located between the first wall edge  626  of the second wall  623  and the partition wall  630 ; a second nozzle airflow outlet  628   b  located between the first wall edge  626  of the first wall  622  and the partition wall  630 ; and a diffusion surface  629  for guiding an airflow in a predetermined direction. The first wall edge  626  of the second wall  623  is folded in an annularly curved or bent manner to form a first Coanda surface  634   a  adjacent to the first nozzle airflow outlet  628   a  and capable of producing the Coanda effect to increase the overall flow rate of the output airflow. The partition wall  630  between the first wall  622  and the second wall  623  is folded either inward (i.e., in the opposite direction of the airflow direction) or outward (i.e., in the airflow direction) in an annularly curved or bent manner to form a closed wall, wherein the closed wall forms a second Coanda surface  634   b  adjacent to the second nozzle airflow outlet  628   b  and capable of producing the Coanda effect. The diffusion surface  629  guides the output airflow in the predetermined direction. 
       FIG. 11  is a schematic view of an example of a forced-draft fan in the present invention. Configured to take in air and eject an airflow, the forced-draft fan  70  disclosed in  FIG. 11  has a forced-draft fan airflow outlet  71 , a forced-draft fan airflow inlet  72 , a forced-draft fan blade  73 , and a forced-draft fan motor  74 . 
       FIG. 12  is a schematic view of an example of a planar fan in the present invention. Configured to take in air and eject an airflow, the planar fan  80  disclosed in  FIG. 12  has a planar-fan airflow outlet  81 , a planar-fan airflow inlet  82 , a planar-fan blade  83 , and a planar-fan motor  84 . 
       FIG. 13  is a schematic view of an example of a jet turbine-blade fan in the present invention. Configured to take in air and eject an airflow, the jet turbine-blade fan  90  disclosed in  FIG. 13  has a jet turbine-blade fan airflow outlet  91 , a jet turbine-blade fan airflow inlet  92 , a jet turbine-blade fan blade  93 , and a jet turbine-blade fan motor  94 . 
     According to the above, the present invention solves the problem that, if the areas of the nozzle openings of a bladeless fan with a Coanda surface are to remain unchanged, the Coanda surface cannot be enlarged without increasing the volume of the nozzle. 
     The present invention is such valuable in this field so that submit an application. While example embodiments have been disclosed herein, it should be understood that other variations may be possible. Such variations are not to be regarded as a departure from the spirit and scope of example embodiments of the present application, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.