DESCRIPTION

The present invention relates to the removal of liquids and/or solids from a gas stream and has particular reference to an airstream generated within floor cleaning apparatus.

Floor treatments machines incorporating vacuum apparatus have become more developed in more recent years, and in particular, the use of vacuum cleaning machines to "suck up" liquids from liquid spills or for use in combination with scrubbing and shampooing machines has resulted in a new generation of floor treatment machines. For example, the traditional shampooing/scrubbing machine which applies a shampoo liquid, and which shampoos or scrubs the floor surface, now includes means for removing liquid from the surface via a vacuum nozzle.

The technology behind vacuum cleaning from a floor surface is well known. A pressure reduction (vacuum) is supplied via a nozzle to create an airstream, the velocity of the airstream entrains within it particles of dirt or liquid. The particles of dirt or liquid are then transported by the airstream along a conduit to a container for either solids and/or liquid. As the airstream debouches into the volume of the container the airstream slows down sufficiently for the bulk of the solids/liquid particles to be deposited within the container under the influence of gravity. A filter medium is provided through which air is withdrawn from the container to trap residual particles not so deposited.

When collecting liquids in this way, there is a need to have a liquid container system which is sufficient to allow for an acceptable duration of cleaning/scrubbing by increasing the period between stops to empty the liquid container. It follows from this that the larger the volume of the liquid container the longer the duration of the cleaning cycle between services. At the same time, however, the

larger the liquid container the more difficult the container becomes to handle when it is full.

Attempts have been made to overcome this problem by providing two containers for receiving liquids.

United States Patent Specification No. 5012549, for example, describes a liquid vacuum extraction system comprising a reservoir for fresh cleaning solution, means including a floor tool for applying said solution to the floor, carpet or other surface to be cleaned, vacuum means for sucking up the solution and contained dirt in an airstream from said surface being cleaned, said system including a pair of spaced apart liquid reservoirs each having an upper open end, a common closure sealing said upper ends, said closure enclosing an inlet communicating with said floor tool for returning air bearing cleaning water and included dirt and an outlet communicating with said vacuum means, said inlet communicating with a flow splitter head within the closure positioned over said liquid reservoirs whereby all of the contained liquid is separated from the air and dropped into each of said liquid reservoirs at essentially equal rates while the air passes through to said outlet.

Experience has shown that the apparatus of United States Patent Specification No. 5012549 does not provide the filling of the containers at an even rate. In practice, one of the containers fills significantly before the other. The unevenness of the filing depends on the precise attitude of the nozzle relative to the floor. If the nozzle becomes slightly disarranged then one of the containers will tend to fill more rapidly than the other. Thus the full potential of the machine for longevity between emptying of the liquid reservoirs and recharging of the fresh cleaning solution is not maintained simply because one of the reservoirs becomes full thus necessitating emptying while the other is probably only half or three-quarters filled to capacity.

A further disadvantage is that, when the apparatus forming the subject of United States patent specification no. 5012549 is employed for a small cleaning task, two reservoirs are obtained each partially full of water. In servicing the machine at the end of the cleaning operation; it is, therefore, necessary to clean two reservoirs each containing a small quantity of dirty water.

The present invention seeks to address these problems and in one aspect of the present invention there is provided a vacuum cleaning extraction system of the kind described in United States Patent Specification No. 5012549 comprising a plurality of spaced apart liquid receiving reservoirs being arranged such that the airstream passes sequentially from one reservoir to another.

In one spect of the present invention, there is provided apparatus for the removal of liquids and/or solids from a gas stream which apparatus comprises a plurality of receiving chambers, each chamber having an inlet for admission of the gas stream and including a reservoir for collecting said solids/liquids separated from the gas stream, and vacuum means applicable to each chamber to draw said gas stream thereinto whereby solids/liquids are collected in said collecting means, characterised in that each chamber is connected in series with the gas stream whereby the gas stream passes sequentially from one chamber to another so that the reservoir of each chamber fills substantially sequentially.

In this way liquids and solids are deposited in the first reservoir and when that is full then deposited in the second. An ancillary effect of this is that the solids tend to be concentrated in the first of the collecting reservoirs, while the liquid in the second and subsequent reservoirs contains substantially less by way of solid content. This permits recycling of the liquid, since once full, the first reservoir acts as a scrubber to remove a substantial proportion of the solids and dirt content whereas the second and subsequent containers contain cleaning liquid having a significantly smaller proportion of solids and dirt content. This liquid in the second and subsequent containers can be released for recycling back into the cleaning solution reservoir thereby permitting re-use of the liquid. This has the effect of prolonging substantially the period between service intervals for the machine.

In another aspect of the present invention, there is provided apparatus for the extraction of liquids and/or solids from a gas stream which apparatus comprises a chamber having an inlet for the admission of said gas stream, collection means for collecting

liquid/solids separated from the gas stream, vacuum means applicable to said chamber via an outlet to draw said gas stream from a source into said chamber whereby the liquid/solids are collected in said collection means, characterised by the provision of two or more chambers, and a collection means associated with each chamber whereby each chamber is provided with means communicating with another chamber, and one of said chambers has a primary inlet for the admission of the gas stream from its source, the arrangement being such that the gas stream passes sequentially through the chambers to said vacuum means and the collection means fill substantially sequentially.

In a further aspect of the present invention the apparatus further includes conduit means between sequential chambers, said conduit means extending between one of said chambers to the inlet of the next sequential chamber, the conduit orientation being such that when the reservoir of said one chamber is full the gas stream entering the conduit entraps excess liquids/solids therefrom and transports said excess into the next chamber. Each reservoir means may form

part of the volume of each chamber, such that the volume of the chamber decreases as the reservoir means fills.

In a particular embodiment of the present invention the apparatus is provided with two reservoir means or containers disposed on the apparatus in a side by side relationship. In the specific arrangement envisaged by way of example, each container is open at its upper end and the pair of containers are closed by a common closure which is substantially divided along the partition wall separating the containers, said partition wall carrying the conduit, one end of which extends through the wall, the other end of which terminates within the upper part of the open end of the first container. The chamber thus defined over said first container is provided with an airstream inlet. The chamber disposed over the second container is connected with vacuum means for reducing the pressure and generating an airflow through the system the arrangement being such that air passes from a cleaning nozzle with entrained dirt and liquid into the inlet in the first chamber and then passes in through the communicating conduit to the second

chamber and the air, substantially freed of liquid and dirt is then exhausted from the second chamber via the outlet to the vacuum means.

In an alternative embodiment the chamber associated with each container includes a partition adapted to overlay said containers, said partition being provided with an inlet portion for each container upstanding from the plane of said partition said partition having an opening communicating with said second chamber and said partition being contained within an outer cover defining a plenum chamber for communication with said vacuum means.

In one aspect of the invention there is provided a machine as described and claimed in published WO specification 93/14684 the whole disclosure of which is incorporated herein by reference. This specification relates to a machine for scrubbing or finishing a floor surface and comprises carriage means adapted for translational movement over a floor surface, a workhead motor means which is carried by said carriage means and is arranged in use to drive said workhead. In a particular embodiment

the carriage means may comprise two horizontally spaced chassis members which carry pivot means for a workhead assembly. The pivot brackets on the workhead assembly are attached to one arm on a horizontal axis generally transverse the fore aft direction of the carriage such that the workhead assembly can privot between its work position and its rest position in which latter position the workhead is disposed forwardly of the carriage. A handle may be used to rock the carriage with respect to the floor surface as in a particular aspect of the invention the rear wheels may constitute the rocking means and the carriage may be rocked forwards and backwards on said rear wheels to effect movement of the workhead between a work position and a rest position. The detail of operation of this is fully described in pending specification no. W093/14684.

In yet another aspect of the invention the carriage means may be adapted to carry a reservoir for collecting liquid, a chamber associated with said reservoir and a suction pump which communicates with said chamber and a conduit which communicates with said chamber and has an inlet at an end remote

therefrom which inlet is disposed juxtaposed the floor surface such that operation of the suction pump causes a reduction of pressure in the chamber which itself causes liquid at the floor surface to be sucked into the conduit at the inlet and to remove the conduit into the chamber where it falls under the influence of gravity into the liquid collecting reservoir, characterised by the provision of at least two reservoirs and arranged such that the air passes sequentially from one reservoir to another whereby one reservoir fills before the other.

Each liquid collecting container may be a box-like structure having a base and integrally moulded upstanding front, rear and side walls. The liquid collecting container or receptacle may be open at its upper end, which opening may be surrounded by a peripheral flange having a smooth upper surface.

The two liquid collecting containers or receptacles may be shaped to be carried on the carriage, one contiguous the other such that the upper surface of each liquid collecting receptacle is substantially continuous with the upper surface of the other

receptacle. This has the advantage that each receptacle contains about a half of the total volume of the liquid collected by the machine, and the receptacles can be removed separately from the machine, thereby facilitating the removal, carrying and emptying of the receptacles when they are full or nearly full.

The chamber associated with each receptacle is defined by a closure member which may be a box-like structure having a base and integrally moulded upstanding side, front and rear wall and a top wall. Preferably, the closure member is arranged to be seated on the upper surface of the liquid collecting receptacles to close the same. The closure member may be divided by a wall which follows the juxtaposed walls of the reservoir to define a chamber closing the upper open portion of each reservoir. One chamber may incorporate a fluid inlet and the other a fluid outlet, which latter is connected with said vacuum means. The bottom surface of the base of the closure member may be smooth to mate with and substantially seal the upper surface of the liquid collecting receptacles.

In a further embodiment of this aspect of the invention, the said wall may carry a conduit to provide communication between the first and second chambers and their associated reservoirs. The conduit may extend through the wall from the first chamber to the second, and on the side of the first chamber, and within it, is cranked downwardly so that the lower end enters the upper part of the first reservoir and terminates at a level within said first reservoir corresponding to the desired maximum liquid level therein.

In a particular aspect of a machine in accordance with the present invention, the receptacles and vacuum means may be moulded on a carriage capable of translational movement over a floor to be treated. The vacuum means may be a suction pump or centrifugal fan carried on the carriage and which is preferably located in the vicinity of or over the rear wheels. The machine may further include a liquid reservoir for containing a detergent solution or liquid polish. Preferably, the reservoir comprises a moulded box-like structure having integral bottom, front, back, side and top walls. The reservoir may have an

outlet which is connected to a conduit which terminates juxtaposed the floor surface. According to one embodiment of the invention, the conduit terminates inside the brush housing juxtaposed the brush holder. The reservoir may have a fluid inlet and a suitable closure therefor. Preferably, the reservoir is adapted to support the liquid collecting receptacle; and in a preferred embodiment of the invention, the upper wall of the reservoir is shaped to mate with the shaped bottom wall of the liquid collecting receptacle.

According to a further aspect of the present invention, the closure member may be hinged to the machine handle such that the member can be rotated between a closed position in which the member is seated on the liquid containers and an open position in which the latter member is lifted away from the said liquid collecting containers. When the member is in the open position, the liquid collecting containers may be removed for emptying.

The containers, liquid collecting reservoir and the closure member may be moulded from suitable thermo-plastic material e.g. polypropylene. Preferably, at least one of the walls of the chamber and/or liquid collecting reservoirs is transparent to allow inspection of the contents.

Following is a description by way of example only and with reference to the accompanying drawings of methods of carrying the present invention into effect:-

IN THE DRAWINGS:

Figure 1 is a schematic side view (partly in section) of a machine in accordance with the present invention.

Figure 2 is a second side view of the machine of Figure 1. Figure 3 is a schematic rear view of the machine of Figure 1.

Figure 4 is a section on the line IV-TV of Figure 1.

Figure 5 is an enlarged detail of the upper part of Figure 4 in accordance with the invention.

Referring to Figure 1, a machine (10) for scrubbing or finishing a floor surface includes a carriage (12) which comprises two horizontally spaced apart forwardly chassis members (18, 19).

The carriage (12) is supported towards its rear end (14) on two spaced apart transit wheels (16) each of which is mounted for rotation on an axle (17) which latter extends transversely of the members (18, 19). The said carriage (12) at it front end (15) carries a workhead assembly (100) which is pivotaly mounted between said members (18, 19) about a horizontal axis (117) which is arranged substantially at right angles to the fore-aft direction of the carriage (12).

Motor (124) of workhead assembly (100) carries a counterweight (130) which is attached to the outer surface of the motor housing and extends rearwardly thereof such that in the first position the weight of the workhead assembly (100) is disposed asymmetrically of the pivot axis (117).

Housing (110) carries two horizontally spaced apart casters (132) which are fastened to a rearwardly facing part of the external surface of the housing (110) such that the said casters are disposed on the same side of the pivot axis (117) as the said counterweight (130) .

Carriage (12) has a handle (25) attached at the rear end (15) of the former, which handle (25) includes an upwardly and rearwardly extending elongate shaft (27) which has an handle-bar (29) fastened to its upper-end. The shaft (27) can be fixed relative to the carriage (12) so that an operator of the machine can use the handle to rock the carriage (12) backwards on its rear wheels (16) with respect to the floor surface, thereby to raise the front end (15) of the carriage, and to lift the workhead assembly (100) away therefrom. As the machine is so rocked the torque exerted by the weight of the workhead assembly (110) about the pivot axis (117) causes the assembly (100) to rotate towards its second position. In the second position, the casters (132) are disposed forwardly of the pivot axis (117) •underneath the brush housing

(110), and the front end (15) of the machine is supported thereon.

It will be appreciated that when the workhead assembly of the machine as described herein is positioned in its second rest position, a pad or brush unit fastened to the pad holder on the motor shaft is exposed to facilitate maintenance and/or removal and replacement thereof. Moreover, the machine is supported in its second position on the said rear wheels and casters thereby to permit of easy transit of the machine.

The upwardly directed reaction exerted on the casters, therefore, exerts a torque about pivot axis (117) which acts to retain the workhead assembly in its rest position as the machine is moved over the floor.

However, the pivot between the workhead assembly and the carriage means may be modified in any manner known to a person skilled in the art to provide a locking or detent means whereby the said assembly is releasably secured in its rest position.

The floor maintenance machine (10) is provided with fluid handling apparatus for supplying a cleaning solution liquid or polish to the floor to be treated with the pad or brush -unit (122). Said apparatus includes a first receptacle (40) which is mounted on said carriage (12) generally over said rear wheels (16).

Said first receptacle includes a generally rectangular bottom wall (42) which is shaped towards one side to define upwardly directed recess (44) (see Figure 3) .

Bottom wall (42) is integrally moulded with two upstanding side walls (43), a generally rectangular rear wall (46) and a front wall (45); which front wall (45) is shaped in its lower half to define a rearwardly directed recess which partially accommodates the motor (124) of the workhead assembly (100) when the latter is in its first working position. Said recess (48) has a rear wall (45A) of arcuate cross-section which is shaped to allow unhindered rotation of the workhead assembly (100) about its pivot axis (117). The side (43), front (45) and rear walls (46) are inter connected at their

upper ends by a top wall (49) which has a downwardly directed recess (50) formed therein, said recess (50) being generally rectangular in cross-section and defining a peripheral flat-topped ridge (57) .

First receptacle (40) also comprises an outlet (not shown) which is formed in the said bottom wall (42) at its lowest point. Said outlet is connected to a conduit which terminates inside brush housing (110) adjacent the pad carrier. First receptacle (40) is also provided with an inlet and a suitable closure therefor.

The said fluid handling apparatus of machine (10) also comprises two second liquid-collecting receptacles (60) which are similar one to the other and are supported in side-by-side relationship on the upper wall (49) of said first receptacle. Each second receptacle (60) (60') includes a front wall (61), a rear wall (62), two side walls (63) and a shaped base portion (64) . Said base portion (64) includes a narrow bottom wall (65) and front, back and side walls (66), (67) and (68) respectively which each extend upwardly and outwardly to meet the corresponding walls of the

second receptacle at an outwardly extending circumferential shoulder (69).

Each receptacle (60) is open at its upper end and is provided with a re-entrant portion (70) to protect against spillage of the contents in handling and which defines opening (71). The receptacles (60) (60') are arranged such that the base portion (64) of each is accommodated within the recess (50) formed in the top wall (49) of the first receptacle (40) and the bottom wall (65) of each is seated thereon; the said shoulder (69) being seated on the said peripheral ridge (51); the receptacles (60) being configured such that their adjacent inwardly facing side walls (63) are contiguous one another, and the outwardly facing side, front and back walls (64), (66) and (67) of base portion (64) abut on the side walls of recess (50) to form an interference fit therewith.

The receptacles (60) (60') together support a closure member (80) which comprises a generally planar top surface (81), a sloping forward surface (87) generally continuous with forward surface (61) of the receptacle, a rear surface (88) and a pair of

substantially erect sides (86). Closure member (80) carries at its lower end a peripheral flange (180) extending about the lower extremity of walls (86, 87, 88) said flange carrying at its outer extremity a downward depending skirt (181) adapted to overlay the upper extremity (171) of containers (60) (60'). The chamber defined by closure member (80) is provided with a central partition (182) generally continuous with the juxtaposed walls of containers (60) (60'). Partition (182) extends downwardly substantially to the plane of the join between the containers so as to define a first chamber (190) and a second chamber (191). The rear wall (88) of the closure defining first chamber (190) is provided with a conduit inlet (192) to which nozzle assembly (91) is attached. Motor (97) is connected via a conduit (not shown) to an outlet (193) in the second chamber (191). Second chamber (191) is also provided with a substantially central baffle (194) extending from the top surface (89) downwardly to the plane containing flange (180).

Central partition (182) is provided with and carries a cranked conduit (200) which is fixedly secured within partition wall (182), the crank end (201) of which

extends downwardly below the opening (71) associated with the first container (60). The lower extremity (202) is champfered at an angle of approximately 20° to the horizontal as shown in Figure 5 to provide for both the passage of air and liquid from chamber (190) and first receptacle (60) into the volume defined between partition (182) and baffle (194) the arrangement being such as to prevent the direct passage of air and air containing water from outlet (203) of conduit (200) direct to outlet (193).

In use, the first receptacle (40) is filled with a liquid polish or detergent solution, and the machine (10) is moved over the floor on its transit wheels (16) with the workhead assembly (100) in its first working position such that the brush or pad is held in working contact with the floor surface. The liquid solution is dispensed at a predetermined rate from said first receptacle (40) to the floor through its outlet conduit, and the pad or brush unit (122) is driven by the said motor (124) to rotate on the floor thereby to effect polishing or scrubbing thereof.

Suction pump (97) effects a reduction of pressure in chamber (191) by withdrawing air therefrom via outlet (193). The reduction of pressure in communicated via conduit (200) to first chamber (190) and the pressure reduction is further communicated to the nozzle assembly (94, 95) by means of inlet (192) and associated nozzle assembly (94). Liquid slurry located on a floor surface is sucked into nozzle (94) and travels up conduit (92) until it reaches inlet (192). The liquid matter and any relevant particulate matter then falls under gravity into first receptacle (60) where it is collected. The air passes via conduit (200) into second chamber (191) where it is diverted around baffle (194) to outlet (193), any residual matter being deposited in second chamber (60'). When the liquid level in first chamber (60) approaches the champfened end (202) of conduit (201), the continued passage of air through the conduit and over the juxtaposed surface of the liquid therein causes some liquid to be further entrained in the airstream passing through the conduit and to pass with the airstream from receptacle (60) into the second chamber (191). As the airstream enters the large volume associated with container (60') the velocity of

the airstream is reduced and the liquid matter thereby is deposited in the second container.

In this way the first container substantially fills first and the second container fills at least in part from the contents of the first container. This means that for a small cleaning job it is only necessary to empty one, namely the first, container (60) since the second container (60') will be substantially free of any contents. Additionally liquid collected from near the surface of the first receptacle (60) will tend to be more free of dirt and debris than that entering the inlet (192). As a result the liquid collecting in the second container (60') will be significantly cleaner and means can be provided (not shown) to recycle the liquid from the second container back to the reservoir (40).