GB2141327A

GB2141327A - Vacuum cleaner

Info

Publication number: GB2141327A
Application number: GB08316642A
Authority: GB
Inventors: Leonard Taylor; Dileep Sharma
Original assignee: LAMSON D D PLC
Current assignee: LAMSON D D PLC
Priority date: 1983-06-18
Filing date: 1983-06-18
Publication date: 1984-12-19
Also published as: GB8316642D0; GB2141327B

Abstract

In an industrial vacuum cleaner comprising a trolley 1, a drum 2 for waste material, and a removable cap 3 on the drum connected by a hose 5 to motor-driven impeller units 7, the drum is mounted on wheels 15 and the trolley has a ramp 22 stored below the deck of the trolley and movable to a position providing a slope from deck to ground level to enable the drum to be wheeled off the deck and so facilitate emptying. <IMAGE>

Description

SPECIFICATION Vacuum cleaner This invention relates to vacuum cleaners and more particularly to vacuum cleaners of the type, generalliy termed industrial vacuum cleaners, comprising an upright, usually cylindrical drum which is mounted on a trolley to enable the drum to be moved from place to place. An open top of the drum engages a cap which may support a motor-driven impellerfor producing sub-atmospheric pressure within the drum. Alternatively a motor-driven impeller or impellers may be mounted separately on the trolley and connected by a duct through an opening in the cap to the interior of the drum. Whether the motordriven impeller is mounted on the cap or elsewhere, the cap will usually house a filter through which dust-laden air passes before reaching the impeller but the filter could also be mounted separately from the cap.

Emptying the drum of waste material can present problems. The cap has first to be lifted offthe drum and stowed out of the way. The drum is usually deep and emptying it can be awkward or involve heavy work. Often, for dry waste, a removable container, such as a paper bag, is provided to line the drum.

When this is full it can be heavy and difficult to lift out because of the height to which it must be raised to clear the rim of the drum.

The present invention consists in a vacuum cleaner comprising a trolley on which is mounted a drum to receive waste material, the drum having a removable cap supporting or connected to a motor-driven impeller for producing sub-atmospheric pressure within the drum, the drum being provided with wheels or rollers supporting the drum on a deck of the trolley and the trolley having a ramp stowable on the trolley and movable to a position of use in which, when the trolley is standing on a level floor, the ramp is supported with one end close to, and at the same height as, an edge of the deck, and the other end on the floor, affording a slope enabling the drum to be run on its wheels or rollers off the deck for emptying and back onto the deck after emptying.

In its stowed position the ramp is preferably stored below the deck of the trolley.

The ramp could be bodily removable from its stowed position and put into its position of use in which it may be supported by the trolley, for example by the engagement of hooks on the ramp or the trolley with a bar or eyes on the trolley or the ramp respectively. Or the ramp could be supported independently of the trolley, for example by fixed or folding legs on the ramp.

It is preferred, however, that the ramp is connected to the trolley by mounting means which retains the ramp on the trolley in both positions and so guides the ramp, on movement from the stowed position, that on reaching the position of use the one end of the ramp is brought into the required relationship with the edge of the deck when the other end rests on the level floor. Means may be provided to enable the trolley to support the end of the ramp which is adjacent the edge of the deck. For example, a projection may be provided at the adjacent end of the ramp to rest on the edge of the deck in the position of use.

The mounting means may slidably connect the ramp to the trolley. The mounting means may comprise at least one ramp guide pivoted to one end of a radius arm mounted on the trolley for angular movement about an axis parallel to the deck. The ramp slidably engages the ramp guide or guides.

The radius arm or arms may be spring urged towards the position occupied when the ramp is in the stowed position.

Stop means may be provided to prevent the ramp being pulled out of engagement with the ramp guide or guides on reaching the position of use and to avoid too wide a gap between the end of the ramp and the edge of the deck. In combination with the radius arm or arms the stop means may be operative when the ramp reaches the outermost limit of its slidable movement relative to the guide or guides to enable further outward movement of the ramp with respect to the trolley to cause the radius arm or arms to swing upwards and raise the adjacent end of the ramp relative to the deck. The upward swing of the radius arm or arms may be opposed by spring means. When the other end of the ramp is lowered to the floor the radius arm raises the end of the ramp adjacent the trolley to rise to the level of the deck.

A bar may be provided mounted on the trolley and lying parallel to but below the level of the deck and beyond the edge of the deck to support the ramp in the position of use. An intermediate part of the ramp rests on the bar. A ramp support may be provided to support the ramp below the deck in the stowed position and to guide it while being moved into the stowed position.

The cap could be completely detachable from the vacuum cleaner while the drum is being removed for emptying but is preferably detachable merely from the drum and remains on the trolley when the drum is removed. Especially when the cap supports a filter unit and/or the motor-driven impeller, the cap may be mounted on the trolley by means for supporting the cap in, at least, an out-of-use position off the drum. The cap-supporting means may guide movement of the cap between its position on the drum and its out-of-use position and may include means for counterbalancing at least a part of the weight of the cap, and apparatus mounted thereon, during movement towards and away from the out-of-use position.

In vacuum cleaners, especially though not exclusively industrial vacuum cleaners, having an upright drum to receive waste material it is convenient to have a disposable bag, for example one made of polyethylene, for actually receiving the waste material. The bag can be lifted out of the drum for disposal when sufficiently filled. If the bag is put in the drum as a simple liner it is apt to collapse inwards and even to be sucked into the air outlet of the drum as soon as the vacuum cleaner is started.

With the aim at least of contributing to the solution of this problem, according to another aspect the present invention provides, in or for a vacuum cleaner having an upright drum and an inlet for waste material to enter the upper part of the drum and fall into and be collected in the lower part of the drum, a holder for a disposable bag for the wastematerial comprising a ring to support the mouth of the bag below the waste inlet, means for retaining the bag on the ring with the mouth held open and upwardly directed, and means for sustaining the ring in the drum,the arrangement being such that an air space is maintained between the outside of the ba-g and the wall of the drum in which air can circulate so as to balance the air pressures inside and outside the bag during use of the vacuum cleaner.

The inletforwaste material may be arranged in the upper part of the wall of the drum or it may be at the end of a conduit inside the drum and leading from an opening through the lower part of the drum, for example as described in Patent Specification 1 524 254.

The support ring may be a strip of flat metal or plastics bent into a hoop with the width of the strip parallel to the axis of the hoop. The means for sustaining the ring in the drum preferably comprises legs secured at their upper ends to the ring, their lower ends being engageable with the base of the drum. Alternatively the support ring could be sustained from the adjacent wall of the drum by brackets on the drum or the ring. The means for retaining the mouth of the bag on the ring may be a retaining ring slightly larger than the support ring and adapted to be passed downwards onto the ring and to surround material of the mouth of the bag folded outwards over the support ring. The retaining ring may be prevented from sliding downwards too far by shoulders provided, for example, by the upper ends of legs of the sustaining means.

A removable collector of rigid or relatively stiff material is preferably provided above the mouth of the bag, the interior of the collector having a hollow conical base sloping to a bottom opening and an upright wall or walls which conform closely to the upper part of the wall of the drum and extend above the level of the inlet for waste material, means being provided for the passage of air between the air space around the outside of the bag and the interior of the drum above the collector. As the collector, unlike the disposable bag, is not made of flexible material a narrow annular gap between the wall or walls of the collector and the wall of the drum can be maintained in use of the vacuum cleaner and may form the means for such passage of air.The collector avoids the risk of overflow of waste material from the bag into the air space and directs into the bag waste material falling from a filter in the cap. The collector may be combined with the retaining ring or other retaining means to form a single unit.

Vacuum cleaners with an upright drum for collecting waste material and, particularly though not exclusively industrial vacuum cleaners, are often required for use in wet situations or actually to pick up water or other liquids. A substantiall quantity of liquid may have to be collected in the drum and there is a risk, especially in powerful machines, of liquid being drawn into the filter and impeller.

To adapt a vacuum cleaner for use in such circumstances according to a further aspect the present invention provides, in or for a vacuum cleaner having an upright drum, an outlet for air from the upper part of the drum to the impeller, and an inlet for waste material to enter the upper part of the drum, a baffle adapted to be removably disposed in the drum and adapted to separate the inlet from the outlet and cause air drawn into the inlet to follow an indirect path between the inlet and outlet of the drum.

The baffle preferably comprises a first element adapted to divide the upper part of the drum into vertically spaced zones of which-the inlet opens into the lower zone and the outlet opens from the higher zone, and a second element depending from the first element between an aperture through the first element and a portion of the first element which in the position of use of the baffle in the drum is adjacent the inlet.

The aperture in the first element enables air to pass from the inlet to the outlet but the second element forces itto follow an extended path in the lower zone before reaching the aperture. The areas of the aperture and of the cross-section of any passages defining the path are preferably, but not necessarily, greaterthan that ofthe inlet so that the air velocity is reduced, helping to separate entrained liquid from the air and to avoid the picking up of liquid from inside the drum.

A float-operated valve may be provided to close the aperture or any equivalent opening in the baffle when liquid accumulated in the drum has reached a predetermined level.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side elevation of a vacuum cleaner according to the invention, Figure 2 is an end elevation of the vacuum cleaner of Figure 1, Figure 3 is a fragmentary sectional view on a larger scale of part of Figure 1, Figure 4 is a partial plan view ofthe vacuum cleaner of the previous figures, Figures5and 6 are a plan and end elevation respectively of a ramp component of the vacuum cleaner, Figure 7 is a fragmentary side elevation of the ramp, Figure 8 is an enlarged view of part of Figure 6, Figure 9 is a side view of a ramp guide component of the vacuum cleaner, Figure 10 is a fragmentary sectional view of part of Figure 1, Figure 11 is a diagrammatic view of a holder for a disposable bag for use in the vacuum cleaner of the previous figures, Figure 12 is a diagrammatic view of a baffle to be fitted to the vacuum cleaner of Figures 1 to 10 when the cleaner is to be used to pick up wet waste material, Figure 13 is a sectional view on line 13-13 in Figure 12.

The vacuum cleaner shown in Figures 1 and 2 is an industrial vacuum cleaner comprising a trolley 1, a drum 2 to receive waste material, a removable cap 3 on the drum inside which is mounted a filter (not shown) and connected by a flexible hose 5 to a plenum chamber 6 mounted on the trolley and carrying three motor-driven impeller units 7 for producing sub-atmospheric pressure in the plenum chamber 6 and, through the hose 5 and the filter inside the cap 3, in the interior of the drum 2.

There is an inlet 8 into the upper part of the drum 2 for waste material which is connected by a hose (not shown) to a nozzle (not shown) suitable for the cleaning work to be done.

The trolley 1 has a frame 9 supporting a flat deck 10 and mounted on wheels 11 and castors 12 on which the trolley can be manoeuvred by means of handles 14.

The drum 2 is itself mounted on wheels 15 by which it is supported on the deck 10. A pair of spring-loaded, releasable catches 16 on opposite sides of the drum hold the drum in place on the trolley and rails 40 are provided on the deck 10 to guide the wheels 15. The cap 3 is embraced by parallel, horizontal portions 17 of limbs 18 forming a U-shaped, horizontal forward part of a support tube 19. Rearward portions of the limbs 18 are turned downwards and slidably and telescopically engage a pair of upright tubes 20 forward of the plenum chamber 6. The limb portions 17 slidably engage guides 39 on opposite sides of the cap allowing some freedom of horizontal movement of the cap.

The support tube 19 may be urged upwards by compression springs (not shown) inside the upright tube 20. Spring-loaded plungers (not shown) are engageable with aligned holes in the telescoping ) tubes 19 and 20 to lock the support tube 19 when the cap is raised,to support the cap in an out-of-use position off the drum 2 while the drum is being emptied. The cap 3 has a depending, circumferential flange 21 (Figure 10) to locate the cap on the mouth of the drum 2 and to house a flexible seal 22 between the cap 3 and drum 2. The upward spring-loading (if provided) of the support tube 19 counterbalances at least a part of the weight of the cap and apparatus mounted on it during movement towards and away from the out-of-use position.The support tube 19 guides movement of the cap between its position on the drum and its out-of-use position. The freedom of horizontal movement of the cap on the limb portions 17 facilitates re-seating the cap on the drum after the drum has been emptied. The cap may be held down on the top of the drum 2 in the position shown in the drawings on the drum by catches, toggle catches for example, directly connecting the cap and drum.

To assist in moving the drum 2 on and off the deck 10 of the trolley a ramp 22 is provided. The ramp 22 is normally stored under the deck 10 but is movable to a position of use, the position shown in Figure-1.

The ramp 22 as shown in Figures 5 to 8 is elongated and of shallow channel cross-section with a base 23, forming the track of the ramp, and upwardly directed walls 24 along its longer edges. Along the upper edges of the walls, the sheet metal of which the ramp is made is bent outwards and then returned inwards to form double thickness flanges 25. At an inner end 26 and an outer end 27 of the ramp 22 the channel is open and at the ends of the base 23 the sheet metal is again returned underneath to form portions of double-thickness. At the outer end 27 a handle 28 is provided. At the inner end 26 a projection 26' is formed by an extension of the base 23.

Inthe stowed position below the deck 10 the ramp is supported by L-section members 29 (Figures 3 and 4) having horizontal flanges 30 on which the outward flanges 25 of the ramp rest and are slidable. The ramp is also slidable in guides 31 (Figures 3,4 and 9), one on each side of the ramp, of channel form with one flange 32 wider than the other flange 33. The flanges 32,33 embrace the longitudinal edges of the ramp, the narrower flange 32 overlying the outward flange 25 of the ramp and the wider flange 33 extending under the marginal portion of the base 23.

A trunnion 34 extends from the web of the channel of each guide 31 and pivotally mounts the guide on one end of a respective one of a pair of radius arms 35 extending from and rigid with a shaft 36 parallel to the deck 10. A helical tension spring 41 connects the trunnion 34 to an anchorage on the trolley and urges the radius arm in a clockwise direction as viewed in Figure 1. A bumper tube 37 is also mounted in front of the frame 9 parallel to but below the level of the deck 10, the ends of the tube 37 being curved rearwards and secured to the sides of the frame 9. The shaft 36 is pivotally mounted on the tube 37 near its points of attachment to the frame by bolts 38 engaging tapped, axial holes in the ends of the shaft.

In the stowed position of the ramp 22, indicated in Figure 4, the handle 28 is exposed at the front of the deck 10. The ramp 22 can be pulled out from its stowed position by use of the handle 28, sliding along the flanges 30 of the ramp supports and through the guides 31. Stops (not shown) prevent complete disengagement of the ramps from the guides 31. When the ramp is fully extended the stops on the ramp engage the guides, causing the radius arms 35 to swing upwards, against the action of the springs 41, to raise the inner end 26 of the ramp.

When the outer end 27 of the ramp is lowered to rest on a level floor on which the trolley 1 is standing, the inner end 26 is raised further and the edge of the base 23 of the ramp becomes substantially level with the adjacent edge of the deck 10. The projection 26' is then able to rest on the edge of the deck 10. An intermediate part of the base 23 near the inner end 26 engages the bumper tube 37 which serves as an intermediate support for the ramp. The co-operation of the stops, guides 31, springs 41 and radius arms 35 holds the adjacent edges of the base 23 and deck 10 close to one another and avoids the forming of too wide a gap between them. The ramp is then in its position-of-use and, after the cap 3 has been raised from the drum on its support tube 19 and the catches 16 released, the drum can be run down the ramp for emptying.The projection 26' by resting on the edge of the deck prevents the from tipping down under the weight of the drum. After emptying the drum can be pushed back up the ramp, the catches re-engaged and the cap 3 lowered onto the drum again. The outer end 27 of the ramp is first pulled, against the action of the springs 41 to disengage the projection 26' from the deck and then lifted after which the ramp is slid back into its stowed position.

The vacuum cleaner is then ready for further cleaning operations.

Figure 11 illustrates the use inside the drum 2 of a holder 51 to enable an impermeable disposable bag 52, such as a plastics bag, made of polyethylene, for example, to be used to collect waste material. The holder 51 comprises a support ring 53 formed by bending a flat strip of metal or plastics and joining the ends to form a hoop with the width of the strip parallel to the axis of the ring. Three legs 54 secured attheirupperendsto the outside ofthesupport ring 53 support the holder in the manner of a tripod, the feet ofthe legs standing on the bottom ofthe drum.

In use of the holder the mouth of the bag 52 is folded outwards over the support ring 53 and held in place by a retaining ring 55 slightly larger than the support ring 53 andwhich clamps the marginal portions of the bag between the rings 55 and 53. The ring 55 is prevented from sliding too far down the ring 53 by its lower edge resting on the top of the legs 54. The diameter of the support ring 53 is such that a substantial annular gap is left between the outside of the bag 52 and the wall-of the drum, to enable air to circulate freely and allow air pressures inside and outside the bag 52 to balance when the vacuum cleaner is in use.

The retaining ring 55 is part of a collector 56 which has a shallow conical base 57 sloping down to a central opening 58. Around the periphery of the-base 57 the collector has an upwardly extending wall 59 only slightly smaller than the inside diameter of the drum. The top of the wall 59 reaches the level of the top of the drum and above the inlet 8 but below the bottom of a filter or other equipment housed in the cap and indicated at 61. An inlet elbow 60 extends inside the drum from the inlet 8. The free end of the elbow is at the centre of the drum and opens downwards over the aperture 58. The elbow 60 is detachable from the inlet 8 to enable the holder 51 and collector 56 to be fitted, an opening in the wall 59 being provided through which the end ofthe elbow 60 can pass to re-engage the inlet 8.

The upstanding wall 59 of the collector extends well above the inlet 8 and lies close to the wall of the drum, while still allowing air to pass. Air can thus circulate between the air space surrounding the bag 52 and the interior of the drum above at least the base of the collector 56, for pressure-balancingpurposes. Waste is directed by the elbow 60 through the aperture 58 into the bag. These arrangements ensure that waste material is almost entirely contained within the bag 52 and prevented-from overflowing into the drum around the bag.

For use in picking up liquids or wet waste, a baffle 71 may be fitted in the drum 2 as shown in Figures 12 and 13. The baffle 71 comprises a first element 72 and a second element 73. The first element is in the form of a shallow bowl with an out-turned lip 74 which is fitted with a seal 75 and rests on the rim of the drum 2. At the centre of the bottom of the bowl is an aperture 76 extended downwards by a short spigot 77.

The second element 73 depends from the bottom of the bowl and is U-shaped in plan section, as shown in Figure 13, with a semi-cylindrical wall portion 78 co-axial with the aperture 76 and extending into parallel wall portions 79. The second element 73 extends downwards to the lower part of the drum. The baffle extends down over a major part of the depth of the drum, for example, 70% to 90% of the depth,typically408 mm in a drum 570 mm deep, leaving a clearance of about 160 mm between the lower edge of the second element 73 and the bottom of the drum.

The bottom of the bowl is just above the level of the top of the drum inlet 8 which is provided with a short, detachable elbow 80 which can be turned about the axis of the inlet 8 so that its mouth can be directed downwards as shown in Figure 12 or in another direction, for example tangentially of the drum. It is important thatthe baffle 71 be correctly located in relation to the inlet 8 so that the semicylindrical wall portion 78 is towards the inlet 8. To ensure correct location the baffle is provided with an annular, depending flange 81 which has in the appropriate position a recess complementary to the inlet elbow 80. The flange 81 prevents the baffle lip from seating on the rim of the drum unless the recess engages elbow 80.

The first element 72 divides the upper part of the drum into vertically spaced zones of which the inlet 8 opens into the lower zone. The higher zone opens to an outlet from the drum through filter 61 and the flexible hose 5. Communication between the two zones is confined to the aperture 76-which air from the inlet 8 can reach only by following a longer, indirect path around the back of the semi-cylindrical wall portion 78 and the free edges of the parallel wall portions 79. The path to be followed by the air entering the drum through the inlet 8 is defined by a passage formed by the inner wall ofthe drum, the second element 73, the underside of the first element 72 and the surface of liquid in the drum.Even at the highest liquid level allowed-in the drum the cross-section of this passage is several times larger than the area of the inlet 8 and of the aperture 76 so that the air velocity along the passage and particularly the velocity of air near the surface of the liquid is very much less than that through the inlet 8 and aperture 76. This induces the deposition in the drum of liquid entrained in the air and helps to avoid the picking-up bythe airflow of liquid from the drum.

To prevent the level of liquid from rising too high in the drum a float-operated valve 82 is provided to close the aperture when the liquid accumulated in the drum reaches a pre-determined level. The valve 82 comprises a float 83 confined by a cage 84 to guide its vertical movement towards and away from engagement of a sealing face 85 of the float with the lower edge of the spigot 77. In the present example the float 83 is an upright cylinder but the float could be of spherical or other convenient shape suitable for closing the spigot 77 and thus, in effect, the aperture 76 when the liquid has reached the predetermined level. With the aperture 76 closed, suction is cut off from the inlet 8 and the drawing in of further waste material is prevented. The cage is made of open mesh material, for example, wire mesh or expanded metal or a skeletal frame with a plastic mesh sleeve, to reduce the risk of debris jamming the movement of the float.

Claims

1. A vacuum cleaner comprising a trolley on which is mounted a drum to receive waste material, the drum having a removable cap supporting or connected to a motor-driven impeller for producing sub-atmospheric pressure within the drum, the drum being provided with wheels or rollers supporting the drum on a deck of the trolley and the trolley having a ramp stowable on the trolley and movable to a position of use in which, when the trolley is standing on a level floor, the ramp is supported with one end close to, and at the same height as, an edge of the deck, and the other end on the floor, affording a slope enabling the drum to be run on its wheels or rollers off the deck for emptying, and back onto the deck after emptying.

2. A vacuum cleaner according to claim 1 wherein in its stowed position the ramp is stored below the deck of the trolley.

3. A vacuum cleaner according to claim 1 or claim 2 wherein the ramp is bodily removable from its stowed position and put into its position of use in which it is supported by the trolley or independently thereof.

4. A vacuum cleaner according to claim 1 or claim 2 wherein the ramp is connected to the trolley by mounting means which so guide the ramp, on movement from the stowed position to the position of use, that on reaching the position of use the one end of the ramp is brought into the required relationship with the edge of the deck when the other end rests on the level floor.

5. A vacuum cleaner according to claim 4 wherein means is provided to enable the trolley to support the end of the ramp which is adjacent the edge of the deck.

6. A vacuum cleaner according to claim 4 or claim 5 wherein the ramp is slidably connected to the trolley.

7. A vacuum cleaner according to claim 6 wherein the mounting means comprises at least one ramp guide pivoted to one end of a radius arm mounted on the trolley for angular movement about an axis parallel to the deck, the ramp slidably engaging the ramp guide or guides.

8. A vacuum cleaner according to claim 7 wherein stop means is provided operative when the ramp reaches the outermost limit of its slidable movement relative to the guide or guides to enable further outward movement of the ramp with respect to the trolley to cause the radius arm or arms to swing upwards and raise the adjacent end of the ramp relative to the deck.

9. A vacuum cleaner according to claim 7 or 8 wherein the or each radius arm is spring urged towards the position it occupies when the ramp is in its stowed position-.

10. Avacuum cleaner according to claim 8 wherein spring means opposes the upward swing of the radius arm or arms.

11. A vacuum cleaner according to any preceding claim wherein is provided a bar mounted on the trolley and lying parallel to but below the level of the deck and beyond the edge of the deck to supportthe ramp in the position of use.

12. A vacuum cleaner according to any preceding claim wherein a ramp support is provided to support the ramp in the stowed position and to guide it while being moved into the stowed position.

13. A vacuum cleaner according to any preceding claim wherein the cap is mounted on the trolley by means for supporting the cap in, at least, an out-of-use position off the drum.

14. A vacuum cleaner according to claim 13 wherein the cap-supporting means guides movement of the cap between its position on the drum and its out-of-use position.

15. A vacuum cleaner according to claim 13 or claim 14 wherein the cap-supporting means includes means for counterbalancing at least a part of the weight of the cap, and apparatus mounted thereon, during movement towards and away from the out-of-use position.

16. A vacuum cleaner according to any preceding claim and having an inlet for waste material to enter the upper part of the drum and fall into and be collected in the lower part of the drum, wherein is provided a holder for a disposable bag for the waste material comprising a ring to support the mouth of the bag below the waste inlet, means for retaining the bag on the ring with the mouth held open and upwardly directed, and means for sustaining the ring in the drum, the arrangement being such that an air space is maintained between the outside of the bag and the wall of the drum in which air can circulate so as to balance the air pressures inside and outside the bag during use of the vacuum cleaner.

17. A vacuum cleaner according to claim 16 wherein the means for sustaining the ring in the drum comprises legs secured at their upper ends to the ring, the lower ends of the legs being engageable with the base of the drum.

18. A vacuum cleaner according to claim 16 or claim 17 wherein the means for retaining the mouth of the bag on the ring is a retaining ring slightly larger than the support ring and adapted to be passed downwards onto the ring and to surround material of the mouth of the bag folded outwards over the support ring.

19. A vacuum cleaner according to any one of preceding claims 16 to 18 which further comprises, above the mouth of the bag, a removable collector of rigid or relatively stiff material, the interior of the collector having a hollow conical base sloping to a bottom opening and an upstanding wall or walls conforming closely to the upper part of the wall of the drum and extending above the level of the inlet for waste material, means being provided for the passage of air between the air space around the outside of the bag and the interior of the drum above the collector.

20. A vacuum cleaner according to claim 19 wherein the collector-and retaining means are combined to form a single unit

21. A vacuum cleaner according to any one of preceding claims 1 to i5and.having an outletforair from the upper part of the drum-to the impeller and an- inlet for waste material to enter the upper part of the drum, wherein is provided for use in picking up liquids or wet waste, a baffle adapted to be remov ably disposed in the drum and adapted to separate the inlet from the outlet and cause air drawn into the inlet to follow an indirect path between the inlet and outlet of the drum.

22. A vacuum cleaner according to claim 21 wherein the baffle comprises a first element adapted to divide the upper part of the drum into vertically spaced zones of which the inlet opens into the lower zone and the outlet opens from the higher zone, and a second element depending from the first element between an aperture through the first element and a portion of the first element which in the position of use of the baffle in the drum is adjacent the inlet.

23. A vacuum cleaner according to claim 22 wherein the area of the aperture and of the crosssection of any passages defining the path are preferably greater than that of the inlet so that the air velocity is reduced, helping to separate entrained liquid from the air and to avoid the picking up of liquid from inside the drum.

24. A vacuum cleaner according to any one of preceding claims 21 to 23 wherein a float-operated valve is provided to close the aperture or any equivalent opening in the baffle when liquid accu mulated in the drum has reached a pre-determined level.

25. A vacuum cleaner substantially as described herein with reference to and as illustrated by Figures 1 to 10 of the accompanying drawings.

26. A vacuum cleaner according to any one of preceding claims 1 to 15 and having a holderfora disposable bag substantially as described herein with- reference to, and as illustrated by, Figure 11 of the accompanying drawings.

27. A vacuum cleaner according to any one of preceding claims 1 to 15 and having a baffle for use in picking up liquids or wet waste substantially as described herein with reference to-and as illustrated by Figures 12 and 13 of the accompanying drawings.