AU5144093A - A ceiling fan air filter - Google Patents

Description

A CEILING FAN AIR FILTER TECHNICAL FIELD

This invention relates to an air filter for use in conjunction with a ceiling fan. Ceiling fans create circulating air currents within a room and the currents cause particles, including dust particles and aerosols, to remain airborne. The vast majority of such particles are prevented from settling and those that do are readily disturbed by persons moving within the room or by externally induced drafts.

It is thought that the airborne particles may contribute significantly to health problems, particularly for persons who suffer from respiratory tract disorders. Such disorders are aggravated when a person is exposed to the airborne particles for prolonged periods of time and this occurs particularly during summer months when people choose to sleep with ceiling fans running throughout the night. BACKGROUND ART In ducted air recirculating systems, including hot air and air conditioning systems, the problem can largely be avoided by locating a filter chamber in the duct circuit and by trapping particles that would otherwise be recirculated. A similar effect is sometimes obtained by locating wall fans in circuit with filter chambers or pads. However, ceiling fans are designed specifically for moving relative large air volumes with little noise, using large slow-speed blades, and they cannot be wall mounted or duct mounted to associated filter chambers without abandoning benefits that make the ceiling fans attractive, particularly for use in the quiet of night. DISCLOSURE OF THE INVENTION

The present invention seeks to minimise the recirculation of particles by providing a particle trap for use in conjunction with a ceiling fan. Thus, the invention provides a filter device which is arranged to be mounted to a ceiling fan and which comprises a filter support which is shaped and sized to embrace at least a portion of the swept area of the fan blades and which permits substantially free flow of air to and from the fan blades. Means are provided for mounting the filter support adjacent the fan blades, and a particle filter is carried by the filter support in such a manner as to trap particles entrained in air which is drawn toward or passed through the fan. The filter support may be located either above or below the fan blades.

The filter device in accordance with the invention may be mounted permanently to a ceiling fan which is sold with the device already fitted, or the filter device may be constructed to be sold as a separate unit for fitting to a pre-existing fan. In the case of a filter device which is intended to be mounted to a previously installed ceiling fan, it is desirable that the device be constructed so that it may be mounted to a tube that is employed to suspend the fan from a ceiling without there being a need to demount the fan from the ceiling. Alternatively, the filter device may be mounted to the fan in an indirect way, for example by suspending the filter support from the ceiling by way of hangers.

The filter support may comprise or incorporate a cowling which, in use, surrounds the fan blades. The cowling may be formed, for example, by moulding from a lightweight plastics material or from thin gauge sheet metal, preferably a light metal such as aluminium. The cowling does not need to have great structural strength, because its main purpose is to carry the particle filter in a manner such that the filter will be exposed to at least a major portion of the air that flows through the fan. The portion of the cowling through which the air passes has a predominantly open structure but includes a skeletal frame or open mesh support upon which the particle filter is carried. Diffusers may be mounted to or be formed integrally with the cowling and be positioned in the path of air flowing through the cowling. The diffusers may be used for the purpose of deflecting the air that passes through the fan blades and for creating a desired air flow pattern. The diffusers may be located either above or below the fan blades and, when located below the fan blades, may be employed for supporting the particle filter. However, the diffusers may be located at one side of the fan blades and the particle filter be located at the other side of the fan blades in the direction of air movement through the fan.

Electric lamps may if desired be mounted to the cowling for functional and/or decorative purposes.

The invention will be more fully understood from the following description of various modes of implementing the invention. The description is provided with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

Figure 1 shows an elevation view of a filter device mounted to a ceiling fan in accordance with a first embodiment of the invention, Figure 2 shows an elevation view of a filter device mounted to a ceiling fan in accordance with a second embodiment of the invention,

Figure 3 shows an underside plan view of the filter unit which is shown in Figure 2 of the drawings. Figure 4 shows an elevation view of a filter element mounted in an indirect way to the ceiling fan and in accordance with a third embodiment of the invention, and

Figure 5 shows a perspective view from the underside of a ceiling fan with light fittings mounted to a cowling portion of the ceiling fan.

MODE FOR CARRYING OUT THE INVENTION

In the embodiment of the invention which is shown in Figure 1, a ceiling fan 10 having an electric motor 11 and blades 12 is suspended from a room ceiling by a suspension tube 14. A filter device which is arranged to trap particles that are entrained in recirculating air is mounted to the ceiling fan. The filter device comprises a cowling 15 which includes a peripheral wall 16, an open lower region 17 within the wall 16, and a generally open skeletal framework 18 extending inwardly from the upper region of the wall 16. The inner region of the skeletal frame 18 includes a hub 19 which is arranged to locate about and be secured to the suspension tube 14.

An air permeable filter 20, which may be in the form of a pad or cloth, is carried by the skeletal frame 18 and, by being located above the fan blades 12, it is arranged to trap airborne particles that are induced to move in a direction toward and through the fan blades 12. The skeletal structure 18 and the filters 20 are selected so as to present minimum impedance to airflow through the cowling and thus, through the fan blades.

The embodiment of the- invention which is shown in Figures 2 and 3 is similar to that which has been described with reference to Figure 1, but the cowling 15 has an open upper region and an expanded metal mesh 21 located in a lower region of the cowling and positioned below the fan blades 12. The mesh carries (that is supports) an air permeable filter 20 which also locates below the blades 12.

A central region 22 of the cowling 15 is formed as a hub and the cowling is secured directly to the motor housing 11 of the fan by way of a screw 23. Also, a metal plate 24 is interposed between the head of the screw 23 and the hub region 22 of the cowling.

In _.the embodiment of the invention which is illustrated in Figure 3, the cowling 15 as seen from below covers the entire swept area of the fan, but the cowling is formed with diffusers 25 which are shaped and positioned to impart a desired direction to the movement of air which passes through the fan.

The diffusers 25 may be formed as segmented groups of louvres, or the diffusers may be formed by pressing or moulding circumferentially extending louvres or openings into a disc-shaped region of the structure.

As an alternative to mounting the cowling 15 directly to the suspension tube 14 (as in Figure 1) or to the motor housing 11 (as in the case of the arrangement shown in Figure 2) the cowling 15 may be located in the desired position relative to the fan by suspending the cowling from the ceiling 13 by way of hangers 25. Such arrangement is shown in Figure 4 of the drawings.

In the embodiment of the invention which is shown in Figure 5 of the drawings, an arrangement of the type which is similar to that shown in Figure 1 is modified in a manner such that electric lamp units 26 are mounted in spaced-apart relationship to and around the cowling 15. A filter device of the type which is shown in Figure 5 is particularly appropriate for doctor's surgeries and commercial situations where both air filtering and high levels of lighting are important requirements.

Claims (10)

1. A filter device which is arranged to be mounted to a ceiling fan and which comprises a filter support which is shaped and sized to embrace at least a portion of the swept area of the fan blades and which permits substantially free flow of air to and from the fan blades, means provided for mounting the filter support adjacent the fan blades, and a particle filter carried by the filter support in a manner such as to trap particles entrained in air which is drawn toward or passed through the fan.

2. The filter device which is claimed in claim 1 wherein the filter support comprises a cowling which is shaped and sized to surround the fan blades.

3. The filter device as claimed in claim 2 wherein the cowling is mounted to a tube which suspends the fan from a ceiling.

4. The filter device as claimed in claim 2 wherein the cowling is mounted to a motor housing for the fan.

5. The filter device as claimed in claim 2 wherein hangers are connected to the cowling and are arranged to suspend the cowling from the ceiling above the fan.

6. The filter device as claimed in any one of claims 2 to 5 wherein the cowling comprises a predominantly open structure surrounded by an encircling wall and wherein the cowling includes a skeletal frame or open mesh within its wall and upon which the particle filter is carried.

7. The filter device as claimed in any one of claims 1 to 6 wherein the particle filter is carried at a level above that of the fan blades.

8. The filter device as claimed in any one of claims 1 to 6 wherein the particle filter is carried at a level below that of the fan blades.

9. The filter device as claimed in any one of claims 2 to 6 wherein the cowling is formed with a lower wall in which diffusers are located for deflecting air that passes through the cowling.

10. The filter device as claimed in any one of claims 2 to 9 wherein electric lamp holders are mounted to the cowling.