Laminar flow radial ceiling fan

Abstract

The prior art has used pitched blades attached to a stationary motor, normally electric. to move air within the confines of a structure or room. The preferred invention incorporates a series of solid discs. The discs are affixed to a stationary electric motor and thus rotate around a central axis. The discs are equally spaced and centrally perforated in a manner that will allow air to flow in high volumes through the perforations and pass along the discs thus exiting symmetrically between each disc perpendicularly to the flow of air that is at its entrance. Due to the less restrictive or low pressure air entrance as well as the correct vertical disc spacing a corresponding increase in the laminar flow is realized. This feature of the preferred invention allows for operation at a rotational speed that practical for use as a ceiling fan.

Claims

1. A method of producing a laminar flow air circulation comprising: an apparatus comprising: a plurality of discs oriented parallel, spaced apart and sharing a common central axis, including a bottom most disc, each disc having an outer circumference and an inner circumference, said inner circumference defining a centrally located aperture; wherein each of said discs are spaced apart at a vertical distance (V) as a function of the inner diameter (ID) according to the formula V=0.0317×ID, wherein said vertical distance is about 0.7 inches to 0.8 inches, a post located at a central axis of said apparatus and having an outer surface, said plurality of discs mounted about said post so as to form an air return space between the surface of the post and the inner circumference of said bottom most disc, said discs mounted such that they freely rotate around their central axis, and said post outer surface having a conical shape such that it acts as an air guide that directs the incoming air without turbulence, said laminar flow being produced through method steps comprising: rotating said discs at a speed sufficient to cause air to flow up into the air return space, along the post air guide surface which redirects the air flow from upward to outward without generating turbulence, then outward between the discs, out beyond the disc outer circumference and a surrounding air space, wherein said method steps operating upon said apparatus produce generally laminar flow air circulation in the surrounding air space.

2. The method as defined in claim 1 wherein the surrounding air space is a room in a building selected from the group consisting of: a private residence, a retail business space, a front office business space and a back office business space.

3. The method as defined in claim 1 wherein said plurality of discs comprise a single drive disc which is driven by a motor and 4 to 7 slave discs which are driven by said drive disc.

4. The method as defined in claim 1 wherein each of said discs are essentially identical, said disc outer diameter is about 30 to 38 inches, and said disc inner diameter is about 20 to 24 inches.

5. The method as defined in claim 1 wherein vertical spacers, mounted between said plurality of discs, hold said discs spaced apart, said vertical spacers further comprising laminar airfoil vanes.

6. An apparatus comprising: a plurality of discs oriented parallel, spaced apart and sharing a common central axis, including a bottom most disc, each disc having an outer circumference and an inner circumference, said inner circumference defining a centrally located aperture; a post located at a central axis of said apparatus and having an outer surface, said post having an outer surface having a conical shape such that it acts as an air guide that directs the incoming air without turbulence, said plurality of discs mounted about said post so as to form an air return space between the surface of the post and the inner circumference of said bottom most disc, wherein each of said discs are spaced apart at a vertical distance (V) as a function of the inner diameter (ID) according to the formula V=0.0317×ID, wherein said vertical distance is about 0.7 inches to 0.8 inches, and said discs mounted such that they freely rotate around their central axis, wherein the size of said air return space, the outer surface shape of said post, the distance space of said plurality of discs, the number of discs and the speed of rotation are all configured to produce a generally laminar flow air circulation in a space surrounding the apparatus.

7. The apparatus as defined in claim 6 wherein the surrounding air space is a room in a building selected from the group consisting of: a private residence, a retail business space, a front office business space and a back office business space.

8. The apparatus as defined in claim 6 wherein said plurality of discs comprise a single drive disc which is driven by a motor and 4 to 7 slave discs which are driven by said drive disc.

9. The apparatus as defined in claim 6 wherein each of said discs are essentially identical, said disc outer diameter is about 30 to 38 inches, and said disc inner diameter is about 20 to 24 inches.

10. The apparatus as defined in claim 6 wherein vertical spacers, mounted between said plurality of discs, hold said discs spaced apart, said vertical spacers further comprising laminar airfoil vanes.

Description

THE DRAWINGS

(1) Objects and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 illustrates a preferred airflow pattern for the air leaving the fan.

(3) FIG. 2 shows a preferred airflow pattern highlighting the air return, a conical return pattern.

(4) FIG. 3 shows the completed view of a preferred embodiment including the unique air flow paths exiting the fan and entering the fan.

(5) FIG. 4 shows an exploded view of the preferred invention.

(6) FIG. 5 is a top view of a single slave disc of the preferred invention.

(7) FIG. 6 is the cross section view of two vertical spacers illustrating the mating cavity.

(8) FIGS. 7A-D show various views of an aerodynamic vane, a design variation which further promotes laminar air flow.

(9) FIG. 8 is the top, or master, drive disc of a preferred embodiment which includes a motor attachment and a smooth conical shape to promote laminar air flow.

(10) FIG. 9 is a top view of the attachment retention ring of a preferred embodiment.

(11) FIG. 10 is a cross-section of the bolt receiving cylinder which is mounted on the attachment retention ring of FIG. 9.

DETAILED DESCRIPTION

(12) One improvement over the prior art is more efficient air circulation. Due to the plurality of discs, their specific size, shape and relative positioning, the fan generates, in a preferred embodiment, a laminar air circulation pattern that efficiently circulates air throughout a standard room. For example, when the fan is located in the center of the ceiling, the air exits the rotating discs horizontally across the ceiling, spreading out uniformly in all directions toward the walls of the room as shown in FIG. 1. At the walls, the air travels downward, parallel with the walls where the air flow turns inward along the floor and travels back toward the room center, see again FIG. 1. Next, the air rotates upward in an inverse cyclonic pattern toward an air return aperture located in the bottom of the fan as show in FIG. 2. Finally, the air enters the fan, through the air return aperture, and thus completing the circulation pattern.

(13) This air circulation is the result of empirical experimentation in various functional fan designs, each of which combine various features of the fan, in particular, the disc dimensions, the disc number and the disc relative positioning.

(14) These air patterns result from the fan illustrated in FIG. 3 which is a built up laminar flow ceiling fan also shown in exploded view in FIG. 4 below. The horizontal arrows 407 show the air exiting the fan beyond the edges of the slave discs 401. The returning air 406 is shown entering the fan through a central air return aperture, see also FIG. 5 103. As the air enters the fan it is smoothly directed outward by the conically shaped portion 408 of the master drive disc described in more detail in FIG. 8 below. This novel feature, directing an air current into and out of a fan without significantly disrupting the laminar flow of that air current is an unique property utterly absent from the prior art.

(15) The FIG. 3 embodiment comprises one master, or drive, disc 405 mounted above an array of eight (8) slave discs 401 below. The through bolts 402 attaching the master disc to the slave discs are threaded through vertical spaces 403 that keep the slave discs 401 parallel and spaced apart a predetermined distance. The master disc also features a smooth invented cone shape that directs air entering through the air entry path 406 to the laminar flow output 407 shown at the side of the array.

(16) FIG. 4 is an exploded view of the complete fan. The electric motor is 501. Through bolts 502 travel through the entire array, binding the entire slave disc array to the master drive disc 503, and terminate at the attachment and retention ring 504. The base air guide 505 covers the motor mounting screw assembly 506 during fan operation but can be removed during fan assembly and servicing. This assembly connects the motor 501 to the master drive disc 503.

(17) The completed slave disc array 507 and master drive disc 503 are shown assembled and affixed to the stationary drive motor 501 by affixing five (5) machine screws through the master drive disc motor mounting screw holes 506 completing the construction of the preferred invention. The motor 501 rotates the entire master drive disc and slave disc array 503 and 507 respectively.

(18) FIG. 5 is a top view of a single slave disc 101 of a preferred embodiment. Each slave disc is preferably injection molded from raw plastic and manufactured identically with a circular opening. An air entry cavity 103 is present in the center of each disc. Each disc in the fan will have this cavity. When the discs are stacked together as shown in FIG. 3, the air entry cavities will create an air return aperture into which air will flow 406 as will be explained more fully below.

(19) The slave disc 101 is preferably manufactured via plastic injection molding so as to create smooth surfaces on both sides. A smooth surface is a preferred surface for promoting laminar flow on a rotating disc(s) 101. Of course any surface designed to promote laminar flow will function in the invention. This is particularly true in high end designs where advanced aeronautical engineering can be employed.

(20) The diameter of the air entry cavity 103 is derived with the following equations. The disc inner diameter (ID) is a function of the surface area (A) of a single disc as follows:
ID=√{square root over (A)}
The outer diameter (OD) of the slave disc 105 is determined as follows:
OD≅1.5×ID
or, more precisely:

(21) $\mathrm{OD}=\sqrt{\frac{4+\pi }{\pi }}\times \mathrm{ID}$
Of course, some variation in the exact ID:OD ratio is allowable. Indeed, under specific conditions (room size, atmospheric pressure) some testing can be carried out and variations of 2, 5, 10 and up to 15 percent could be necessary to achieve optimal performance.

(22) In a preferred embodiment, the surface area (A) is about 500 sq. inches, the outer diameter (OD) is about 34 inches and the inner diameter (ID) is about 23 inches.

(23) An optimal number discs in the array 301 has been determined. The fan works more efficiently as one increases the number of slave discs from one (1) to eight (8). (Note, if one includes the master disc then this range is two (2) to nine (9).) In the preferred embodiment, there is a marginal, but significant increase in efficiency as one increases the discs in the array from seven (7) to eight (8). Surprisingly, eight appears to be an upper limit as no increase in efficiency is observed when one increases the number beyond eight.

(24) Item 102 depicts an integral spacer with a vertical cylindrical or aerodynamic shape. The space between discs, the vertical dimension (V), is a function of the disc outer diameter (OD) and inner diameter (ID) as follows:
V=(OD−ID)×0.0625
In a preferred embodiment, the vertical dimension (V) is 0.75 inches. In another preferred embodiment about 0.7 to about 0.8 inches.

(25) While the preceding formula provides a useful solution for designing an embodiment of the claimed invention, there is of course, an allowable variance in the vertical dimension, but it is surprisingly small. We estimate that laminar flow will persist as one increases the vertical distance by about 10 percent but will have ceased after the vertical distance is increased by 100 percent. Of course, for high end uses one can determine the maximum vertical dimension limit for a particular embodiment by brute force experimentation. One simply builds various fans with different vertical dimensions until one finds the optimal distance for which laminar flow predominates over turbulent flow and maximizing the air volume moved.

(26) FIG. 6 is a vertical cross section of the spacers. A set of spacers are distributed around the slave disc in a uniform circular pattern at a distance that is, in a preferred embodiment, one third (⅓) of the distance from the ID of the disc to the OD of the disc. In a preferred embodiment, a total of 10 integral vertical spacers are molded along the arc signified by the dashed line 104 in FIG. 5 and dispersed equally as described above.

(27) FIG. 6 illustrates a preferred design allowing for vertical stacking of the spacers. As described above, the spacer(s) 102 provide for uniform vertical separation by and between each disc in the slave disc array 401 and feature a center hole 102a that allows the through bolt 402, 502 to pass through the disc array. In addition the integral spacer has a mating attachment and alignment cavity 101b that conforms to and accepts the vertical spacer counterpart 102b that will result in the next successive disc to rest on the shoulder 103b of the vertical spacer.

(28) FIGS. 7A-D illustrate laminar airfoil vane which can, optionally, be connected in the vertical spacers of FIG. 6. FIG. 7A is an axonometric view. FIG. 7B is a top view. FIG. 7C is a front view and FIG. 7D is a right side view. The height 703 of each vane 701 is less than that of the vertical spacer to which the vane is mounted and the diameter of the mounting hole 702 is slightly larger than the outer diameter of the vertical spacer. Taken together, these features allow the vane to rotate freely. The entire vane can change its angle of attack to align with the incoming laminar air movement which can vary from time to time due to changes in air speed, changes in motor RPM etc. These vanes 701 augment the output air speed due to the centrifugal force of a vertical vane rotating and placed in the path of the incoming laminar flow air. The effect is similar to that that of taking a flat piece of cardboard and waving it in front of one's face to create a cooling breeze.

(29) The vane as illustrated is a preferred embodiment and may take on differed shapes depending on the type of laminar airfoil desired. The vanes can also be made stationary if so desired.

(30) FIG. 8 is a depiction of the top master drive disc 301 which provides the attachment base for the slave disc(s) array 401 and the drive motor through motor mounting holes 303. The master disc 301 is preferably molded as a single piece. The master drive disc 301, in axonometric view, shows the bolt through holes 302 that allow the bolt to pass through and connect to attachment retention ring 201. Note that the alignment cavity 304 pattern is identical to that of FIGS. 5 and 9 so that the through bolts and the vertical spacers 102 can pass from the upper most disc through the array to the retention ring on the bottom of the fan. Note again that the master drive disc has a conical conformal air guide 305 that aids the entry of air as well as increasing the laminar flow by providing an unobstructed air passage into and out of the rotating disc array.

(31) FIGS. 9 and 10 illustrate the retention ring and retention ring bolts, respectively. The attachment retention ring 201 is shown in top view. The purpose of the retention ring is to receive the bolts that pass through the master drive disc 301, see FIG. 8, and each slave disc 101 in the disc array. FIG. 10 shows an alignment and retention ring bolt receiving cylinder 201a, 202a designed to recess into the bottom slave disc 101 and is formed to accept the threaded bolt through a central hole 102a, of the bolt receiving cylinder. These retention bolts are distributed in a pattern that will match that of the integral vertical spacers 201. This pattern is depicted by the dashed line 203. The bolt receiving cylinder 201a is conformal to the alignment cavity 101b at the bottom of the bolt. The attachment retention ring 201 is affixed to the bottom disc of the array 401 so that its top surface is flush to the bottom most disc.

(32) The preferred invention as a unit will have the number of discs as described by the aforementioned equation. The operational rotational speed of the preferred invention is within the normal range for a conventional ceiling fan. The motor 501 is designed to accommodate various speeds depending on the user's desired rate of laminar flow air. The formula below can be used to describe the force of the airflow. This is defined as the difference in pressure generated by the air exiting the fan over the surrounding air pressure, (P2−P1).

(33) $P2-P1=\frac{\left(\mathrm{fluid}\mathrm{density}\times \mathrm{angular}{\mathrm{velocity}}^2\right)}{2\left(R{2}^2-R{1}^2\right)}$
where the “fluid density” is the standard air density and R2 and R1 are the distances to the disc outer edge and inner edge, respectively, as measured from the disc center of rotation.

(34) As described above, the air flow patterns of prior art fans are inefficient. They are generally limited to creating a single column of air that displaces the surrounding air. The size of this air column is limited by the diameter of the blades rotating about the hub of the fan. Also, the air column exits a fan located in the center of the room, in a typical installation, where the air column has a limited effect at any point lateral to that air column until contact is made with a horizontal surface of the room. During the summer the air column, somewhat cooler and denser then the surrounding air, will deflect downward which will allow hot air to collect near the ceiling, a very inefficient way to cool a room.

(35) In describing the invention, reference are made to preferred embodiments and illustrative advantages of the invention. Those skilled in the art and familiar with the instant disclosure of the subject invention may recognize additions, deletions, modifications, substitutions, and other changes which fall within the purview of the subject invention and claims.

(36) For example, one of the embodiments described above has eight (8) discs in the array as an optimal number. This array size, however, is dependent on the fan being designed for household use in an ordinary sized room. There is, however, no theoretical reason that a fan be this particular size. Indeed, given the appropriate budget, one could design a fan array suitable for large industrial spaces. In these applications, the air return aperture would be larger and the optimal number of discs in the array could be much greater. Most likely, these larger discs would be more expensive to manufacture. The discs would be subject to greater centrifugal forces and this, in turn, would require proportionally stronger, more expensive, materials. Nevertheless, there are no theoretical problems with constructing an array that could handle a large warehouse or an aircraft hangar. The device can also be placed in a room in buildings such as: a private residence, a retail business space, a front office business space and a back office business space.

(37) In addition to the design features described above, the inventors specifically envision that any air dynamic feature that promotes laminar flow will be useful in certain embodiments of the claimed invention. This description has mentioned only a few, rather cost effective features. Depending on the budget available, additional features also become suitable.

SUMMARY OF MAJOR ADVANTAGES OF THE INVENTION

(38) After reading and understanding the foregoing detailed description of an inventive laminar flow ceiling fan in accordance with preferred embodiments of the invention, it will be appreciated that several distinct advantages of the subject laminar flow ceiling fan are obtained.

(39) At least some of the major advantages include providing a disc array 401 made of plastic and injection molded with integral vertical spacers. The disc array is easily constructed without a jig due to the integral vertical spacers 102 that allow the vertical stacking of the discs to be accomplished. The completed disc array 401, when rotated by drive motor 501 will intake unobstructed air via the open air entrance 406 and expel the laminar flow air at a high volume and lower RPM, relative to the prior art, in all directions 360 degrees parallel to the direction of rotation. When used and in relation to the prior art ceiling paddle fans the induced circulation of the preferred invention homogenizes the air within the room to cause even temperature distribution of the heated or conditioned air within without any change to its direction of rotation.