GB2278771A - Extracting airborne dust - Google Patents

Abstract

An appliance for use in removing airborne dust disturbed from an object 32 or surface comprises an electric blower 22, a dust filter 26, and a portable head that incorporates opposed air blowing and air suction apertures 16, 18 straddling an accessible zone 30 that is traversed by a column of air moving between the blowing and suction apertures. <IMAGE>

Description

Dust Cleaning Appliance Field of the invention The present invention relates to a domestic appliance for dust cleaning.

Description of the prior art A vacuum cleaner (portable or transportable) usually has a brush accessory for attaching to the suction hose to provide for dust cleaning of surfaces or objects other than the floor. Such an attachment is however not suited for cleaning fine surfaces such as furniture and mirrors or intricate and delicate objects such as ornaments, pictures, carvings and house plants, all of which are commonly found in homes and shops. The attachment is clumsy to manipulate because the whole unit has to be kept moving to provide the brushing action, and it is of such stiff construction and has such powerful suction that it should never be used in direct contact with delicate objects.

Obiect of the invention The present invention seeks to provide an appliance specially suited for dust cleaning of fine and delicate surfaces and objects.

Summarv of the invention According to the invention, an appliance for use in removing air-borne dust disturbed from an object or surface comprises an air blower, a dust filter, and a portable head that incorporates opposed air blowing and air suction apertures straddling an accessible zone that is traversed by a column of air moving between the blowing and suction apertures.

In use, the zone traversed by the column of air is positioned over or adjacent the object or surface to be dusted. Its accessibility permits the object to be located within the zone at the same time as allowing access for a conventional brush or duster to be used manually to dislodge and disturb dust resting on the object. However, instead of the dust remaining in suspension in the ambient air, it is carried by the air column and filtered by the filter within the appliance to prevent it from settling again at a later stage.

For cleaning of dust from intricate and delicate surfaces and objects, the best method is to use a soft brush or a very light feather duster which can be manipulated with great ease and dexterity around the delicate object without even disturbing it. It is very effective in removing any dust that has settled on the object by simply agitating the dust and throwing it into the air where it is held in suspension for a period. The problem is that in an enclosed space found in the home and in shops, the agitated dust is only suspended in the air and will eventually settle down again on the floor as well as on the objects and surfaces being cleaned by the duster.

A possible solution to the problem would be to arrange a suction hose from a vacuum cleaner to be positioned in the vicinity of the feather duster when the latter is being used so as to suck some of the suspended dust into the vacuum cleaner. However, this is found to be ineffective because the speed of air movement in the surrounding near the inlet of the suction hose drops very rapidly with distance from the inlet and the dust agitated by the duster tends to float away instead of being drawn into the suction hose.

The present invention is predicated on the realisation that the collection of dust laden air can be carried out more efficiently by defining a working zone across which a column of moving air is induced by a combination of blowing at one end and sucking at the other.

By arranging this working zone within a portable and easily positioned head, the invention allows any dust raised by the duster within a sizable space in the vicinity of the working zone to be immediately captured by the column of moving air and transported to pass through the dust filter that is connected in series with the air moving system. In this way, dust cleaning with a soft duster is effortless and effective with no risk of dust escaping and settling again at a later stage.

Conveniently, the entire appliance is of lightweight and portable construction with the air blower powered from the mains voltage supply or from a replaceable or rechargeable battery. If the appliance is sufficiently portable the motor of the blower may be built into the portable head, thereby avoiding the need for a separate casing and flexible hose connection.

The appliance may be designed to be operated by a person with one hand holding a handle of the appliance and positioning the appliance with its working zone near or around the surface or object to be cleaned and the other hand holding a soft brush or feather duster which is used to perform the dust cleaning function on the surface or object over which the working zone has been positioned.

The working zone should define an open and unobstructed working space through which the soft duster can be manipulated freely around the object being cleaned. This working zone may conveniently be defined by two prongs making up the ducts connected to the outlet and inlet respectively of the push and pull air moving system, which are spaced apart to define the working zone with elongate openings on their sides facing each other, one opening delivering air from the air moving system and the other opening sucking air by the air moving system.

An alternative embodiment of the present invention may comprise a push and pull air moving system which has two air blowers, one blower for delivering air across the working zone and another blower for sucking air from the working zone. This avoids the problem that if the same air is constantly recirculated, it may allow a single motor to overheat. The configurations of the blowing and sucking impellers may also in this case be separately optimised.

Preferably, the outlet and inlet openings are protected by mesh or grills for preventing small objects from being sucked into the appliance.

Preferably, the dust filter forms part of a container which has a non-return flap for preventing dust particles from emptying from the container after they have been drawn into the container.

In the case where the appliance is used to clean dust from a surface with small objects lying on it, additional means may be provided to deflect the air flow from the outlet of the air moving system away from the plane of the working zone of the appliance and towards the surface, making use of the surface as a supplementary deflector to deflect the column of moving air back towards the inlet of the air moving system. This deflected column of moving air thus serves to dislodge dust from the surface and the objects by blowing, even without the aid of a feather duster. Instead of deflecting the air flow from the outlet of the air moving system, nozzles may also be provided on the side of the appliance when required, to blow air at the surface and the objects.

The invention may also be implemented as an attachment for E vacuum cleaner hose. In this case, a turbine driven by the aspirated air may drive a blower fan.

Brief description of the drawings The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of an appliance of the invention, being a section on the line I-I in Figure 2, Figure 2 is a schematic section on the line II-II in Figure 1, Figure 3 is a schematic exploded perspective view of the air moving system of the invention, and Figure 4 is an attachment for a vacuum cleaner embodying the invention.

Detailed descrittion of the drawings The appliance 10 in Figures 1 and 2 comprises a main casing 20 that incorporates a mains or battery operated motor driving an impeller 22. A box fitted within the casing 20 contains a filter element 26 and non-return flap valve 24.

The casing 20 has two prong-like hollow extension arms 12 and 14 which face each other across a zone 30 that acts as E dust extraction zone. The arm 12 has orifices 16 designed to blow air into the zone 30 while the arm 14 has orifices 18 for sucking air from this zone and recirculating it to the fan 22 through the one-way flap valve 24 and the filter 26. The entire appliance is light-weight and has an handle 28 by means of which it can be held and positioned about an object to be cleaned.

In Figure 1 the appliance is shown positioned around a spherical object 32 that is brushed by a fine haired brush or feather duster 34. The duster dislodges any dust that may be resting on the surface of the object 32 but instead of the dust remaining in suspension in the ambient air, it is transported by the column of recirculating air represented by the arrows in Figure 1 to allow the dust to be collected in the filter 26. The purpose of the flap valve 24 is to ensure that the dust in the filter is never blown back or spilled.

There is a tendency for the negative air pressure to be concentrated at the end of the arm 14 closer to the casing 20 instead of the suction being evenly distributed over the entire length of the arm 14. This could result in some of the blown dust-laden air escaping into the atmosphere instead of being recirculated through the filter 26. The design of the blowing and suction orifices shown schematically in Figure 3 is intended to mitigate this problem In Figure 3 the blowing aperture 16 in the arm 12 is formed as a long slit with a flared mouth to direct a flat and divergent column of air towards the arm 14. The arm 14 also has an elongate slit 18 that is much wider that the slit 16 and formed at its upper and lower edges by curled over lips 18a, 18b.Air entering the slit 18 is forced up and down into the region of the lips 18a, 18b which define two tubes 14', 14" that extend along the length of the arm 14. These tubes serve to distribute the negative pressure more evenly along the length of the arm 14 to ensure all the air blown from the slit 16 is captured and recirculated.

Though the invention has been described by reference to a self-contained unit, it will be possible to connect a head by means of one or more hoses to a separate casing containing a blower fan and a filter. It has been found in practice that because the unit is only called upon to collect floating dust it need not be as robust or powerful as a vacuum cleaner but instead may compare in size, weight and power with a portable hair dryer.

If the appliance is to be constructed as an accessory for a vacuum cleaner then it may either be connected to the blowing and sucking sides of the vacuum cleaner motor or, where no connection is available on the positive pressure side of the motor, a blower may be built into the appliance head driven by a turbine rotated by the suction air.

Figure 4 shows such an attachment for a vacuum cleaner hose.

The attachment comprises a hollow, generally U-shaped casing 40 similar to that described in Figure 1 with a blowing arm 42 and a suction arm 44. The essential difference residing in the air moving system. In the present embodiment, air drawn by a vacuum cleaner through a connector 46 drives a turbine 52. The bearing support 54 for the shaft 50 of the turbine is apertured to permit air to flow through it. At the other end, the shaft 50 is supported in a solid partition 58 which does not allow air to pass through and, beyond the partition 58, the shaft 50 carries an impeller blade 56 of a blower that draws in air through a port 48 in the casing 40.

In this way the blower 56, which is powered by the turbine 52, directs air along the arm 42 and discharges it out of the blowing apertures in this arm. The air traverses the accessible dust extraction zone and is drawn into the arm 44 by the suction from the vacuum cleaner, creating a circulation represented by the dashed arrows. More air from the surrounding will also be drawn into the arm 44, represented by the solid arrows, and the combined flow carrying the dust is sucked into the vacuum cleaner where it is filtered.

A bleed hole 60 is optionally provided to reduce the suction in the arm 44 in order to prevent the dusting tool or objects in the dust extraction zone from being caught by the powerful suction from the vacuum source. This highlights the difference between a conventional vacuum cleaner attachment and the present invention in that whereas a vacuum cleaner collects dust by strong localised suction, this invention relies on a gentle directed flow of air to carry away the dust.

Claims (8)

Claims

1. An appliance for use in removing air-borne dust disturbed from an object or surface comprising an air blower, a dust filter, and a portable head that incorporates opposed air blowing and air suction apertures straddling an accessible zone that is traversed by a column of air moving between the blowing and suction apertures.

2. An appliance as claimed in claim 1, wherein the appliance has two essentially parallel prong-like hollow arms making up the ducts connected to the outlet and inlet of the blower, which are spaced apart to define the accessible zone with elongate openings on their sides facing each other.

3. An appliance as claimed in claim 1 or 2, wherein the dust filter forms part of a container which has a non-return flap for preventing dust particles from emptying from the container after they have been drawn into the container.

4. An appliance as claimed in claim 1, wherein the motor of the air blower is mains operated.

5. An appliance as claimed in claim 1, wherein the motor of the air blower is battery operated.

6. An appliance as claimed in claim 1, wherein means are provided to deflect the air flow from the outlet of the blower away from the plane of the accessible zone of the appliance and towards a surface to be dusted.

7. An appliance as claimed in any preceding claim, wherein the air blower and dust filter are housed within the portable head.

8. An appliance as claimed in claim 1, 2 and 6, wherein the portable head comprises a turbo-blower driven by air drawn at least partly from the suction aperture of the head through the turbine of the turbo-blower via a flexible hose connectable to the suction port of a vacuum cleaner, the blower of the turbo-blower drawing ambient air and delivering it to the blowing aperture of the head.

g. An appliance constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.