GB2219524A - Vacuum Cleaner - Google Patents

Abstract

A vacuum cleaner for removing hot peat ashes from a fireplace has a metal suction hose 3, 6, a metal container 1 to receive the ashes, a fire-resistant inward flow filter bag 5 in the container, a metal fan-motor unit 2 and an outlet hose 4 ending in a secondary filter 32, which may comprise packed peat fibres. The filter 32 may be located back in the fireplace from which ashes are removed and may itself be burned after use. The suction hose opens tangentially into the container. A handle 25 is moved up and down to clean bag 5 by shaking. <IMAGE>

Description

"Vacuum cleaners'' This invention relates to vacuum cleaners. In particular, the invention is directed to vacuum cleaners for handling hot material, such as ash, especially hot ashes from the combustion of peat.

The combustion of peat as a fuel leaves a substantial body of very hot ash which can retain its heat over a lengthy period, for example, overnight. A common way of clearing out ashes from a grate in which peat has been burnt is to use a vacuum cleaner. With peat ashes, this can present a hazard, in that the ashes can remain at an elevated temperature and can also contain quantities of incompletely burnt material. When such material is drawn up into a conventional vacuum cleaner made to a substantial extent from plastics material, the vacuum unit may go on fire. In addition, the fine peat ash can lead to clogging up of the filters of a conventional vacuum cleaner and thereby to possible irreversible damage of the unit.Further disadvantages may arise from the very fine nature of peat ashes and the possibility of carry-through of fines or dust not trapped by the filter of the vacuum cleaner. Such carried-over material may be blown around the room in which the cleaning operation is being conducted, depositing a layer of dust on furniture and objects therein. Alternatively, even if the filtration is fully effective, hot gases or unpleasant odours emanating from the hot ashes may be blown around the room from the outlet of the vacuum cleaner.

Accessory units for use with conventional vacuum cleaners are known and examples are described, inter alia, in Belgian Patent Specification No.

1,000,510 and British Patent Specification No. 2,156,239A. Integral vacuum units for use in handling ashes in particular are described in, inter alia, U.S. Patent Specifications Nos. 4,739,535; 4,355,434; 4,342,131 and 3,585,788. U.S. Patent Specification No. 3,618,302 discloses an air cleaner incorporating a spark arrester. Of the foregoing specifications, U.S. 3,618,302 provides an after filter, but specifically in the context of a closed cycle of operation, while U.S.

3,585,788 provides a series of filters including a final cloth filter for gas discharge to atmosphere. British Patent Specification No.

2,156,239A provides a flexible filter element which can be shaken manually to remove particulate material adhered thereto. A similar feature is provided by U.S. Patent Specifications Nos. 3,358,316 and 3,597,902, albeit not in the context of a fire-resistant unit. None of the foregoing disclosures provide a construction of vacuum cleaner specifically suited to the gathering of peat ash, in particular, which is characterised by the presence of a substantial body of exceedingly fine material.

It is an object of the present invention to provide a vacuum cleaner overcoming at least some of the disadvantages previously recited and capable of safely lifting and clearing a body of hot ash, and in particular, a body of hot ash including peat ashes.

According to the invention, there is provided a vacuum cleaner comprising a metal container for receiving waste material, fireproof suction means for establishing a flow of air and/or gas through said container between an inlet thereto and an outlet to atmosphere spaced from the container, a filter of fire resistant material disposed in the path of said flow from said inlet to said outlet for separating, from said air and/or gas flow, at least a proportion of waste material entrained therein, and downstream filter means for separating, from air and/or gas exiting from said outlet to atmosphere, fines material entrained therein not previously trapped by the fire resistant filter.

In a favoured embodiment of vacuum cleaner according to the invention, said downstream filter means comprises a chamber for receiving a mass of replaceable fibrous filtering material, to extract, from the downstream air and/or gas flow, any remaining fine particles of waste material not intercepted by the primary fire-resistant filter. The vacuum cleaner preferably also comprises a fire resistant downstream discharge hose, communicating between an outlet from the container and an air/gas discharge end to atmosphere of the hose, and said chamber of the downstream filter means may suitably be located at said discharge end of the downstream discharge hose.In use of the vacuum cleaner of the invention, this downstream filter, the housing of which is suitably apertured to facilitate exi': to atmosphere of downstream air and/or gases from said chamber within which the mass of replaceable fibrous filtering material is received, may be located within the flue of the grate being cleaned, so that any hot gases carried through the unit or any dust not filtered out by the various filtering systems provided within the vacuum cleaner can be discharged into the chimney without discomfort or danger. Said mass of replaceable fibrous filtering material may suitably comprise peat fibres. As and when the downstream filter fibre material becomes clogged with dust, it may be removed from the fines filter housing chamber and itself burned in a fire, or disposed of in any other suitable manner.Peat fibres being biodegradable, where peat is used as the fibrous filtering material, it may, as an alternative to burning, be used in horticulture.

In an especially favoured configuration of the vacuum cleaner of the invention, said container is defined by an open-ended circular cylindrical drum and a removable lid mountable on the drum to close off the open end thereof, and a metal baffle is disposed within the container drum in the path of air and/or gas flow between the inlet to the container and said fire resistant filter to establish turbulence in the path of movement of air and/or gas entering said container for separation, from said flow of air and/or gas, of larger particles of waste material entrained therein, the baffle being circularly cylindrical in shape, of a lesser diameter than the diameter of the container drum, and extending coaxially with the container drum into the interior thereof from said removable lid.

Preferably, a fireproof waste material intake hose is provided for communicating between a waste material pick-up end of the intake hose and the container inlet, the inlet to the container opening into a substantially annular space defined between the interior of the wall of the container and the exterior face of said baffle and comprising means for directing said air and/or gas flow entering the container in an initially circumferential direction within said annular space, to establish an initially cyclonic path of movement of said air and/or gas flow entering said container to further facilitate separation, from said flow, of said larger particles of waste material entrained therein, and said container inlet and outlet are each provided externally of the container with means for enabling parallel alignment of said intake hose and a discharge hose in use of the cleaner.This parallel alignment enables the cleaner to be positioned in a convenient manner during use, with both hoses extending more or less in straight lines from the container to the grate, the intake hose to collect the ashes and the discharge hose to vent gases to the flue.

In an advantageous construction, the filter is formed from flexible material, is generally bag-shaped, and is supportable in a generally circular cylindrical configuration of use between a stiffening member extending around the mouth of the bag and a base plate attached to the closed end of the bag, the base plate being displaceable between a working disposition in which it is located at a spacing from the stiffening member to maintain the bag in said generally circular cylindrical configuration of use and a filter cleaning disposition in which the base plate is moved towards the bag mouth stiffening member. Thus the filter bag is essentially transformable between a fully extended working configuration and a collapsed cleaning configuration. By rapid displacement of the base plate to repeatedly cycle the bag-form filter alternately through these configurations, particles of waste material adhering to the exterior of the bag may be shaken free therefrom.

Said base plate is most suitably displaceable by means of a generally J-shaped support member, the shorter arm of the J being attachable to the base plate and the second and longer limb thereof extending through a sleeved guide aperture in the lid of the container to an operating handle portion for axial displacement of said J-shaped member relative to said lid The vacuum cleaner of the invention also preferably comprises latch means for selectively inhibiting displacement of said J-shaped member.To this end, a transverse pin is provided extending substantially diametrically through the longer limb of the J-shaped member at a location towards its handle portion end, and the latch means comprises a pivotable member mounted on the lid of the container and having a portion engageable over said transverse pin in a displacement-inhibiting disposition of the latch means. The necessity for a latch arrangement arises out of the tendency for the bag-form filter to be urged towards its collapsed configuration under the effect of suction during use of the cleaner.The latch enables the base plate to be maintained at its full spacing from the bag mouth by preventing sliding axial displacement of the longer limb of the J-rod, but the bag may still be shaken to clear accumulated dirt from it by moving the latch into a release disposition and displacing the J-rod manually upwardly and downwardly, whenever required.

For additional security against damage by hot ashes, in the vacuum cleaner of the invention, the fireproof suction means suitably comprises a motor of substantially all-metal construction, and the motor is selectively drivable at one or other of two different speeds. By selectively operating the unit of the invention at either high speed or low speed, the level of suction may be controlled, and the cleaniing apparatus may be used in such a way that only relatively light material is lifted from the grate, if so required. In addition and alternatively, especially with the lower speed of operation, the apparatus of the present invention may also be used as a bellows for accelerating ignition or reignition of a fire, by directing air flow from the outlet or discharge hose towards a fire to be revived or being lit.

According to another aspect of the invention, there is provided a vacuum cleaner comprising a container for receiving waste material, suction means for establishing a flow of air and/or gas through said container between an inlet thereto and an outlet therefrom, and a filter disposed in the path of said flow from said inlet to said outlet for separating from said air and/or gas flow at least a proportion of waste material entrained in therein, wherein said filter is of a fire resistant material.

For ease of use, the container of the vacuum cleaner according to the invention may be mountable on a base frame having wheels or castors.

Alternatively, and preferred according to the present invention, the container is held on a support framework or base having feet, by virtue of which the vacuum cleaner may be stood on the floor adjacent to the grate or fireplace to be cleaned.

In an alternative filter support arrangement, the base plate may be located at the extremities of longitudinal members of a filter support structure. Said support structure is preferably displaceable between a working disposition in which said base plate is located to maintain the bag in said generally circular cylindrical configuration of use and a filter cleaning disposition in which the base plate is moved into the vicinity of the bag mouth stiffener. Thus, in this arrangement also, the bag is again transformable between a fully extended working configuration and a collapsed cleaning configuration.

The longitudinal members of the support structure may be defined by two legs or limbs, a handle portion linking the ends of these legs or limbs remote from the ends thereof associated with or attached to said base plate. The legs then most suitably pass through apertures provided in said removable lid of the container. The vacuum cleaner may be provided with a spring means arranged to urge this embodiment of support structure into its working disposition, in which the bag is in its extended or filtering configuration. The rate of the spring may be selected so that, in operation, the suction is sufficient to cause the bag to cycle between its fully extended working configuration and a partly contracted configuration, this continual cycling serving to establish a self-cleaning effect during use of the unit.

The unit of the invention provides a safe and efficient method for removing consumed ashes, and in particular peat ashes, from a grate or fireplace, without any hazard to the user or any risk of damage to the vacuum cleaner. The fire-resistant nature of the primary filter and the use of fire-resistant materials for the various housings and drive units of the system remove any possibility of danger to the user and also disposes of any risk of setting fire to either the apparatus itself or other objects in the region of the fireplace.

An embodiment of the invention will now be described having regard to the accompanying drawings, in which: Figure 1 is a pictorial view of a first embodiment of vacuum cleaner in accordance with the invention, Figure 2 is a sectional side view of the vacuum cleaner of Figure 1, Figure 3 is a pictorial view, part cut-away, of the lid of the vacuum cleaner of Figures 1 and 2, together with the various components associated therewith and mounted thereon, Figure 4 is a part cut-away pictorial view of the downstream fines filter of the vacuum cleaner of Figures 1 to 3, Figure 5 is a schematic part-sectional view of a second embodiment of vacuum cleaner comprising features of the invention, Figure 6 is a top view of the cleaner of Figure 5, and Figure 7 is an exploded view of the component parts of the vacuum cleaning unit of Figures 5 and 6.

As shown in Figures 1 to 4, a vacuum cleaner in accordance with the principles of the present invention comprises a generally drum-shaped container 1, arranged with its longitudinal axis of symmetry substantially vertical, a motor unit 2 mounted at the upper end of the container 1, an inlet line 3 for conducting gas or air and entrained waste material to the container, and an outlet line 4 for conveying output air or gas from the cleaning unit to a location remote therefrom for discharge to atmosphere. A fire-resistant filter 5 within the container 1 serves to separate waste material in particulate form from the gas or air flow in which it is entrained. The fire-resistant nature of the filter 5 provides the unit of the invention with its capability of handling hot combusted material such as ashes and the like.

The container 1 preferably consists of a steel drum provided with a carrying handle 18, the drum being open at the top and this open end being closed off in use of the cleaner by a lid 12, held in place by a locking band 13. The lid 12 may be of mild steel and is furnished with air inlet duct means and other units of the invention, including the motor unit 2. A suitable size of electric motor is a 275 watt unit running at 3,000 r.p.m. in normal service, fed from from a 220 volt single phase supply, and mounted within a motor cover 28 on the top of the drum container, which is itself typically approximately 290 mm in diameter and some 400 mm tall. The main suction pipe or inlet line 3 suitably consists of a flexible galvanised hose having a tapered aluminium neck and provided with an inlet end fitting 6 for sucking up ashes and dirt.This tapered end may optionally incorporate a handle, suitably of the open type with a rubber grip. The outlet pipe 4 is suitably of flexible plastics, made resistant to heat. The filter 5 is suitably of Teflon (Trade Mark) gauze. Arms 8 are provided on the lid 12, upstanding from its upper surface, around which the hoses 3 and 4 may be wound in a storage configuration of the vacuum cleaner of the invention.

Within the generally circular cylindrical container 1, a baffle 11, also of generally circular cylindrical configuration, extends downwardly from the lid 12 of the container and is aligned longitudinally with the axis of the container 1, so that container 1 and the baffle 11 are concentric. The baffle 11 may be welded or otherwise affixed to the inner or lower side of the lid 12. This mild steel baffle skirt or deflector cowl 11 thus encloses or surrounds the Teflon filter 12 so as to create a cyclone effect within the container 1 during use of the invention. To this end, an annular space is defined between the interior of the side wall of the container 1 and the exterior surface of the baffle 11. An inlet aperture 14 in lid 12 is fitted with an intake double 900 elbow 15 communicating between the intake line 3 and the interior of the container 1 in the region of this annular space. The interior 900 elbow portion of unit 15 extends into the annular space on the lower side of the lid defined between the interior of the wall of container 1 and the baffle 11.

This internal 900 elbow portion of unit 15 thus brings the gas flow into the annular space of the container in a direction such that the gas and entrained waste material exit from this internal portion of elbow 15 in a circumferential direction to move in a cyclonic manner through the annular space between baffle 11 and the interior of the wall of container 1. The elbow 15 and the other fittings of the unit are preferably of stainless steel where required to be resistant to corrosion, while the remaining components not exposed to harsh conditions may be of mild steel.

During cyclonic movement through the annular space, heavy particles of waste material fall to the floor of container 1 and out of the air flow. The circumferentially moving air stream whirls around through the annular space and subsequently turns towards the axis of the container, in the open space in the lower region of the container below the lower rim of baffle 11. Thus the air flow is then carried around the lower lip of the baffle 11, and, under the action of the suction drive of motor unit 2, the air and/or hot gases are drawn upwardly in the axial direction to encounter filter 5. Further particulate material contained in the air is separated by this filter. Thus a coating of extracted waste material particles builds up on the exterior of the filter 5 in the course of its use.Filter 5 is formed from a fire-resistant material as already described, which may be a silicon-based fabric capable of resisting high temperatures, but is also of sufficiently fine weave to ensure that there is relatively low carry-through of fine particulate material entrained in the air flow.

Further features of this filter are described subsequently.

Further external features of the container include support frame 16 on which it may be mounted for use. The support frame 16 is provided with feet 17, as shown in Figure 1, so that the base or bottom of the drum is spaced from the floor on which the unit stands. Frame 16 also provides a counterbalancing or underlying weight to keep the unit stable during use and storage. The handle 18 facilitates lifting of the entire unit, or, as required, carrying of the container 1 to a location where material gathered within it may be emptied out.

Turning now to the filter itself, the mouth of the filter 5 is maintained in a generally circular shape by means of a stiffening member in the form of ring 21, which serves to maintain the filter mouth in a generally ring-shaped configuration. The open mouth of the filter is secured, by means of ring 21, to the underside of an exhaust chamber 35 provided on the underside of lid 12, to surround an exhaust chamber entry port 36, by suitable means, not specifically represented in the drawings, but which may suitably include a plurality of set screws or the like engaging through ring 21.At the lower or closed end of the generally bag-shaped filter 5, a base plate 22, also of circular shape but in this case solid rather than annular, is located within the interior of the bag to maintain it in a generally cylindrical configuration of use, when the base plate 22 is spaced from the stiffener 21 by an extent sufficient to bring the side wall of the flexible filter bag into an extended circular cylindrical shape. The base plate 22 is secured to and within the clsoed end of the bag filter 5, by means again subsequently described.

A filter support structure is defined by filter drive rod 24, used to displace the filter from its extended cylindrical configuration into a looser disposition, so that the filter may be shaken by external manual pump-type action to dislodge dirt on its external periphery.

The filter drive rod 24 is generally J-shaped in configuration, having a longer or main arm 38 extending upwardly from the vicinity of the base plate 22 to and through the lid 12 of the vacuum cleaner, to terminate in an operating handle or knob 25. The rod portion 38 is guided in its passage through lid 12 by means of a bearing bush or sleeve 26. At the lower end of the J-shaped member 24, a transverse rod portion 39 connects long arm 38 with the shorter upright arm portion 41 of the J, which terminates at its upper end in a pair of mounting arms 42, extending transversely relative to-the axis of the short arm portion 41, and provided with screwholes 43.Bolts 52 extend through screwholes 43 and through corresponding holes in base plate 22, and are tightened up to secure base plate 22 to mounting arms 42 and thereby grip the end closure region of filter bag 5 between the base plate 22 and the mounting arms 42. Thus the base plate 22 is disposed within the container and within the filter, while the handle or knob 25 is located above and externally of the container. By moving knob 25 upwardly and downwardly, the filter may be displaced from an extended generally circular cylindrical working configuration, in which the side wall of the filter is fully extended or stretched, to a collapsed or filter cleaning disposition, in which base plate 22 is displaced towards stiffener 21 and the side walls of the filter bag are completely collapsed.By rapidly manually cycling the filter bag between its stretched and collapsed dispositions, any dirt particles adhering to the exterior or filtering side of the bag may be detached and caused to fall to the base of the container, as the filter alternates between these two configurations.

In order to ensure that the filter bag 5 remains fully stretched during normal operation and is constrained against contraction or collapse under the influence of the suction created by the motor unit 2, latch means are provided for restraining J-rod 24 against unintended movement during use. For this purpose, a transverse pin 44 is mounted extending through a diametral hole in rod portion 38, near handle 25, for co-operating association with a latch member 7, mounted on the upper exterior face of the lid. The latch member consists of a plate pivotally mounted by means of a pin 47 on the lid, having a latch handle portion 45 to one side of the pivot pin and a forked end 46 at the opposite end of the latch plate.In order to engage the latch, the latch plate is pivoted sideways with the J-rod 24 pushed downwardly to bring the filter bag into its fully extended disposition, so that the forked end 46 of the latch member engages around rod portion 38 above transverse pin 44 to thereby prevent upward displacement of rod portion 38 due to engagement of pin 44 against the lower faces of the fork of latch portion 46 embracing rod portion 38. In this way, the filter bag 5 is held in its extended or working disposition.

The motor of the vacuum cleaner is sheathed by the cover 28 from the external environment. An outlet aperture 31 in the lid 12 allows gas to flow from the region downstream of the filter 5, defined by the exhaust chamber 35 to outlet pipe or hose 4. Exhaust chamber 35 is provided with the entry region 36 around the periphery of which the mouth of the filter bag 5 is secured by the stiffening ring 21, while the outlet port 31 communicates between an outlet region 37 of the exhaust chamber 35 and outlet line 4, by means of an outlet elbow 19.

Outlet elbow 19 is a single 900 elbow, to bring outward gas flow through 900 from its generally axial exit from chamber 35 through the outlet aperture from chamber region 37. The double inlet elbow 15 has an external 900 elbow portion to bring inward gas through 900 to pass axially through the aperture 14 in the lid 12, while the second 0 internal 90 limb of the elbow redirects the gas again into a circumferential direction to produce the cyclonic effect in the annular region between the container wall and the baffle 11.The two external portions of the elbows 15 and 19 extend in the same direction, so that in use of the invention, both the inlet hose 3 and the outlet hose 4 can be arranged parallel to one another, to extend in a generally linear manner between the grate to be cleaned and the vacuum cleaner unit, the intake hose 3 collecting the ashes and other dirt and the outlet hose 4 discharging downstream gas to the flue extending from the grate.

The fines filter housing 32 is provided at the downstream end of line 4, and a final filtering of the air flow takes place through this unit. Filter unit 32 consists of a generally cylindrical housing having an internal filter space 48, which is packed with a body of fibrous material, such as peat fibres, for fulfilling the filtering function. This final filter extracts virtually all of any remaining dirt still entrained in the air flow leaving the vacuum unit, which then passes out through holes 49 in the end face of the broadly cylindrical fines filter unit 32. An engaging groove 51 enables interconnection of the fines filter 32 with the discharge end of hose 4 such as by a push fit.In use of the invention, filter unit 32 is preferably located within the flue of the grate being cleaned, so that gases and any remaining dust discharged from the apparatus may be harmlessly released into the flue rather than within the room in which the fireplace is situated.

The motor of the unit of the invention is most suitably a two-speed machine, controlled by switch 33 and fed by a suitable power cable terminating in a conventional plug for insertion into a socket. Used at the lower speed, the cleaner of the invention may be used to pick up lightweight ashes, while it may also be employed to generate a draught by blowing air through the outlet line 4, for use in reviving a quiescent fire or igniting a new fire, without use of intake hose 3 for ash collection purposes.

Use of the invention generally resembles that of any other vacuum cleaner, save only the placing of the outlet filter within the flue.

The initially cyclonic air flow within the container serves to separate large particles of ash or other waste, and particles remaining entrained in the air flow turning over the lip of baffle 11 and encountering filter 5 are largely eliminated by the filter 5 itself.

Remaining dust particles are taken care of by exit filter pack 32.

The filter 5 can be readily shaken free of any large accumulation of particles by upward and downward displacement of handle 25.

Contraction of filter bag 5 under normal operation is prevented by the latching arrangement. By selecting an appropriate motor speed using the two-position switch 33, a suction level may be set up suitable for removing ash and smaller waste particles, while leaving larger material within the grate for possible reuse, typically by use of the lower speed, while high speed operation may be used to clear substantially all waste material. Finally, as already mentioned, the positive air flow created through outlet line 4 may also be used as a bellows to build up a fire during its initial ignition phase. The motor power is sufficient for both cleaning and blowing purposes.As compared with conventional vacuum cleaners, the suction created by the blower results, in the present invention, in an exiting air flow through outlet line 4, rather than, as is the case in many known constructions, in an air flow around and past the motor unit itself of the cleaner.

As shown in Figure 5, an alternative construction of a vacuum cleaner in accordance with the principles of the present invention comprises a container or bucket 101, arranged with its longitudinal axis of symmetry substantially vertical, a motor unit 102 mounted at the upper end of the container, an inlet line 103 for conducting gas or air and entrained waste material to the container, and an outlet line 104 for conveying output air or gas from the unit to a location remote therefrom. A fire-resistant filter 105 within the container 101 serves to separate waste material from the gas or air flow within which it is entrained. The fire-resistant nature of the filter provides the unit of the invention with its capability of handling hot combusted material such as ashes and the like.

Considering now also Figures 6 and 7, the detailed construction of the apparatus shown in Figure 5 will now be disclosed. Within the generally circular cylindrical container or bucket 101, a baffle 111, also of generally circular cylindrical configuration, extends downwardly from the lid 112 of the container and is aligned longitudinally with the axis of the container 101, so that container and baffle 111 are concentric. An annular space is thus defined between the interior of the sidewall of container 101 and the exterior surface of baffle 111. Baffle 111 may be welded or otherwise affixed to the inner or lower side of lid 112. Lid 112 is held on container 111 by means of a locking band 113.An inlet aperture 114 in lid 112 is fitted with an intake elbow 115 extending into the annular space on the lower side of the lid defined between container 101 and baffle 111 and communicating at the aperture 114 with inlet line 103. Inlet line 103 typically consists of a flexible tube of known kind ending in an orifice device for sucking up waste material. Elbow 115 brings the gas flow through 900 on entry into the container from its initially axial direction of entry so that the gas and entrained waste material exit from elbow 115 in a circumferential direction to move in a cyclonic manner through the annular space between baffle 111 and the interior of the wall of container 101. During this cyclonic movement, heavy particles of waste material fall to the floor of container 101 and out of the air flow.The circumferentially moving air stream whirls around through the annular space and subsequently turns, in the open space in the lower region of the container, towards the axis of the container.

Thus the air flow is carried around the lower lip of baffle 111, and, under the action of the suction drive of motor unit 102, the air and/or hot gases are drawn upwardly in the axial direction to encounter filter 105. Further particulate material contained in the air is separated by the filter. Thus a coating of extracted waste material particles builds up on the exterior of the filter in the course of its use. The filter is formed from a fire-resistant material, possibly of a silicon-based fabric, capable of resisting high temperatures, but also of sufficiently fine weave to ensure that there is relatively low carry-through of fine particulate material entrained in the air flow.

Further features of the filter are described subsequently.

The remaining external features of the container are a support frame 116 on which it may be mounted for use. Support frame 116 preferably has wheels or castors 117, so that the assembled unit can be readily moved around to different points of use. A handle 118 facilitates lifting the entire unit, or, as required, removal of the container for emptying out material gathered within it.

Turning now to the filter itself, the mouth 121 of filter 105 is maintained in a generally circular shape by a stiffening member, not shown in Figures 5 to 7 of the drawings, which serves to maintain mouth 121 in a ring-shape. This open mouth of the filter is secured to the underside of lid 112 by suitable means, again not specifically represented in these Figures. At the lower or closed end of bag-shaped filter 105, a base plate 122, also of circular shape, serves to maintain the bag in a generally cylindrical configuration of use, when base plate 122 is spaced from the stiffener or mouth 121 so as to bring the side wall of the flexible filter bag into an extended circular cylindrical shape. Base plate 122 is secured to the closed end of bag filter 105.A filter support structure 123 includes longitudinally-extending limbs or legs 124, which are attached to base plate 122 and extend upwardly therefrom externally of the filter. The upper ends of these legs or limbs 124 are bridged or connected by a handle 125. The legs or limbs 124 of support structure 123 pass through apertures 126 in lid 112 of container 101. Thus the base plate 122 is disposed within the container, on the lower side of the filter, while the handle 125 is located above and externally of the container.

By moving handle 125 upwardly and downwardly, the filter may be moved from an extended generally circular cylindrical working configuration, in which the side wall of the filter is fully extended or stretched, to a collapsed or filter cleaning disposition, in which base plate 122 is brought into the vicinity of or into juxtaposition with stiffener 121, and the side walls of the filter bag are completely collapsed. By rapid cycling of the filter bag between the stretched and collapsed dispositions, any dirt particles adhering to the exterior or filtering side of the bag may be detached and caused to fall to the base of the container, as the filter alternates between these two configurations.

In order to ensure that the filter bag 105 remains fully stretched during normal operation, a spring 127 is mounted between handle 125 and a motor cover 128. Spring 127 serves to urge support structure 123 into a disposition in which it holds filter bag 105 in its extended or working configuration.

Cover 128 sheaths motor 129 of motor unit 102 from the external environment. An outlet aperture 131 in lid 112 allows gas to flow from the interior or downstream side of filter 105 driven by the fan or exhauster portion of motor unit 102, to outlet line 104. Outlet line 104 then extends from container 101 to a downstream or fines filter housing 132, where final filtering of the airflow takes place. Filter unit 132 preferably consists of a housing with a detachable cover and is packed with a body of fibrous material, which may be formed from peat fibres. This final filter extracts any remaining dust still entrained in the airflow leaving the vacuum unit.In use of the invention, filter 132 may be located within the flue of the grate being cleaned, so that gases and any remaining dust discharged from the apparatus are harmlessly released into the flue rather than within the room in which the fireplace is situated. The motor 129 is most suitably a two speed unit, controlled by switch 133 and fed by a power cable 134 terminating in a conventional plug for insertion into a socket.

Use of the invention is exactly the same as other vacuum cleaner, save only the placing of the outlet filter within the flue. The initially cyclonic airflow within the container serves to separate large particles of ash or other waste, and particles remaining entrained in the airflow turning over the lip of baffle 111 and encountering filter 105 are largely eliminated by the filter 105 itself. Remaining dust particles are then removed by filter pack 132. The filter bag 105 can be readily shaken free of any large accumulation of particles by upward and downward displacement of handle 125. In normal operation, depending on the degree of suction generated, partial contraction of filter bag 105 may take place under the action of the suction, so that handle 125 moves upwardly a short distance and spring 127 is partially extended.Oscillation or cycling of the extension of the filter may take place, with spring 127 alternately being extended by the suction force acting on the filter and then acting to re-extend the filter into its full working configuration. This results in a self-cleaning action during use of the invention, cutting down the frequency of filter replacement or manual filter cleaning. By selecting an appropriate motor speed using the two position switch 133, a suction level may be set up suitable to remove ash and smaller waste particles, while leaving larger material within the grate for possible reuse. Finally, the positive airflow created through outlet line 104 may also be used as a bellows to build up a fire during its initial ignition Dhase.

Typically, the motor may be of 250 W, which provides adequate power for both cleaning and blowing purposes.

The vacuum cleaner in accordance with the invention is especially suited to handling hot materials, in particular ashes, and especially peat ashes. The unit of the invention enables such handling to be carried out safely and conveniently, and without spreading dust and dirt through the space in which the fireplace is located.

Claims (12)

1. A vacuum cleaner comprising a metal container for receiving waste material, fireproof suction means for establishing a flow of air and/or gas through said container between an inlet thereto and an outlet to atmosphere from the container, a filter of fire resistant material disposed in the path of said flow from said inlet to said outlet for separating, from said air and/or gas flow, at least a proportion of waste material entrained therein, and downstream filter means for separating, from air and/or gas exiting from said outlet to atmosphere, fines material entrained therein not previously trapped by the fire resistant filter.

2. A vacuum cleaner according to Claim 1, wherein said downstream filter means comprises a chamber for receiving a mass of replaceable fibrous filtering material.

3. A vacuum cleaner according to Claim 2, comprising a fire resistant downstream discharge hose, communicating between an outlet from the container and an air/gas discharge end to atmosphere of the hose, wherein said chamber of the downstream filter means is located at said discharge end of the downstream discharge hose.

4. A vacuum cleaner according to Claim 2 or Claim 3, wherein said mass of replaceable fibrous filtering material comprises peat fibres.

5. A vacuum cleaner according to any preceding claim, wherein said container is defined by an open-ended circular cylindrical drum and a removable lid mountable on the drum to close off the open end thereof, and a metal baffle is disposed within the container drum in the path of air and/or gas flow between the inlet to the container and said fire resistant filter to establish turbulence in the path of movement of air and/or gas entering said container for separation, from said flow of air and/or gas, of larger particles of waste material entrained therein, the baffle being circularly cylindrical in shape, of a lesser diameter than the diameter of the container drum, and extending coaxially with the container drum into the interior thereof from said removable lid.

6. A vacuum cleaner according to Claim 5, comprising a fireproof waste material intake hose for communicating between a waste material pick-up end of the intake hose and the container inlet, the inlet to the container opening into a substantially annular space defined between the interior of the wall of the container and the exterior face of said baffle and comprising means for directing said air and/or gas flow entering the container in an initially circumferential direction within said annular space, to establish an initially cyclonic path of movement of said air and/or gas flow entering said container to further facilitate separation, from said flow, of said larger particles of waste material entrained therein, wherein said container inlet and outlet are each provided externally of the container with means for enabling parallel alignment of said intake hose and a discharge hose in use of the cleaner.

7. A vacuum cleaner according to Claim 6, wherein the filter is formed from flexible material, is generally bag-shaped, and is supportable in a generally circular cylindrical configuration of use between a stiffening member extending around the mouth of the bag and a base plate attached to the closed end of the bag, the base plate being displaceable between a working disposition in which it is located at a spacing from the stiffening member to maintain the bag in said generally circular cylindrical configuration of use and a filter cleaning disposition in which the base plate is moved towards the bag mouth stiffening member.

8. A vacuum cleaner according to Claim 7, wherein said base plate is displaceable by means of a generally J-shaped support member, the shorter arm of the J being attachable to the base plate and the second and longer limb thereof extending through a sleeved guide aperture in the lid of the container to an operating handle portion for axial displacement of said J-shaped member relative to said lid.

9. A vacuum cleaner according to Claim 8, comprising latch means for selectively inhibiting displacement of said J-shaped member.

10. A vacuum cleaner according to Claim 9, wherein a transverse pin is provided extending substantially diametrically through the longer limb of the J-shaped member at a location towards its handle portion end, and the latch means comprises a pivotable member mounted on the lid of the container and having a portion engageable over said transverse pin in a displacement-inhibiting disposition of the latch means.

11. A vacuum cleaner according to any preceding claim, wherein the fireproof suction means comprises a motor of substantially all-metal construction and the motor is selectively drivable at one or other of two different speeds.

12. A vacuum cleaner substantially as described herein with reference to and as shown in the accompanying drawings.