Hitherto conventional carpet cleaning machines have normally comprised a single motor or a double motor arrangement, wherein both motors were mounted to each other wherein an exhaust port of one motor communicated with an inlet port of another motor. In the single motor arrangement there was created a vacuum or suction effect wherein air was drawn through a hose which communicated with a housing of the single- motor machine and dirt and other impurities were caught in a filter or trap located in the housing. The motor incorporated an ^' impeller which was located in a vacuum or suction chamber located in the housing wherein air was accelerated or drawn through the chamber from an inlet thereof to the exhaust port of the motor. A fundamental disadvantage of conventional carpet cleaning machines or vacuum machines was that in some cases it was considered eminently desirable especially in industrial applications to increase the amount of air drawn through the housing so as to improve the carpet cleaning efficiency of the machine. In the case of a single motor arrangement the power often generated by the single motor was often insufficient to draw enough air through the

housing to develop sufficient suction for efficient carpet cleaning. In the aforementioned double motor arrangement it was often considered that the double motor arrangement did not extract sufficient water and dirt from the carpet as it

^ should. Thus it was theoretically considered that the double motor arrangement should provide twice as much power as the single motor arrangement. However while twice as much power may be generated by the double motor arrangement this was certainly not reflected in extraction efficiency. ® The main reason for this was that because a second motor was rear mounted to a first motor the efficiency of the second motor was often impaired because of the amount of effort required in regard to drawing air through the first motor. In this situation the second motor was only sucking or

15 drawing on the exhaust air from the first motor which had nowhere near the velocity of the inlet air through the first motor. This resulted in overall reduction of air flow through the carpet cleaning machine. Thus where one could reasonably expect twice as much air to be drawn through the 0 double motor machine as the single motor machine this did not occur for the aforementioned reasons.

U.S. Patent 4,202,070 describes a vacuum apparatus adapted for use in self service type car washes or the like which comprised an inner shell wherein a plurality of vacuum 5 motors .are located in a common end wall thereof. The plurality of vacuum motors provided a suction means within the inner shell when energised. There was also provided a

monolithic concrete outer housing surrounding the inner shell which also enclosed the top and bottom of the inner shell. A plurality of doors are disposed on the outer housing which provide (1) means to allow removal of particles drawn into the inner shell and (2) vent means for the vacuum motors and for servicing of the motors. A suction tube fitting extends through the concrete outer housing into the inner shell and is located below the plurality of vacuum motors. The suction tube fitting attaches to a suction tube such that when the vacuum motors are energised particles or the like are drawn through the suction tube opening into the inner shell.

While U.S. Patent 4,202,070 describes suction apparatus employing a double motor arrangement wherein each motor was located parallel to each other through apertures • in the common end wall this arrangement was considered disadvantageous for several reasons.

Firstly if it was desired to employ a plurality of vacuum motors in a suction apparatus which was incorporated in a vacuum cleaner which was portable or mobile such as in cleaning carpet or upholstery the location of all of the motors in a common end wall was inappropriate because this meant that it was necessary to provide an effective counter weight at the opposite end of the suction apparatus which was totally undesirable both in manufacture as well as in marketing. This also meant that the vacuum cleaner was extremely heavy and cumbersome to use.

Another disadvantage in regard to the vacuum cleaning apparatus of ϋ.S Patent 4,202,070 was that incorporating both vacuum motors in a common end wall was undesirable in relation to maintenance purposes for reasons of inaccessibility. Also it was relatively difficult to employ vacuum motors of varying capacities if such was considered desirable.,

Hfc was also considered that the extraction efficiency of the vacuum apparatus shown in U.S. Patent 4,202,070 would be impaired over the passage of time because of the mounting of both vacuum motors in a common end wall thereof. Over the period of time impurities such as dirt and other contaminants would build up within the inner shell and this would adversely affect ^' the operation of the motors to obtain a double suction effect. While removal of impurities was provided for by using one of the doors complete removal of such impurities would have been difficult to achieve because of access to the interior surface of the concrete outer housing.

Another disadvantage of the vacuum cleaning apparatus shown in U.S. Patent 4,202,070 was that the structure of same was relatively complicated especially in regard to the provision of a monolithic concrete outer housing and the provision of vent means for the vacuum motors. This also meant that the vacuum apparatus of U.S. Patent 4,202,070 would have been relatively expensive to install as well as unduly time consuming insofar as

installation time was concerned.

Another significant disadvantage of U.S. Patent 4,202,070 is that "dead spots" could occur at the end of the housing remote from the pair of suction motors thereby providing a decrease in extraction efficiency if the air flow was obstructed.

It therefore is an object of the invention to provide suction apparatus which may alleviate the aforementioned disadvantages of the prior art. 0 The suction apparatus of the invention includes a housing having an internal chamber and also having a suction outlet and at least a pair of suction motors each having an impeller and an exhaust port wherein each suction motor is located about the suction outlet and substantially opposed ' 5to each other in plan and wherein each impeller is located *. within or adjacent to said internal chamber and each exhaust port vents exteriorly of said internal chamber.

The housing may have any suitable shape such as being cylindrical, cuboidal or being in the shape of a o olygonal prism or polyhedron.

In one embodiment the housing may be cylindrical having the suction inlet located on the round side wall and a pair of suction motors located in apertures in each opposed end wall of the housing. 5 In another embodiment the housing may be in the shape of a triangular prism having three side walls and a pair of opposed end walls. In this arrangement there may be

provided three suction motors wherein each suction motor is located in a mounting aperture in an associated side wall and the suction inlet is located on one end wall of the prism. However, it will be appreciated that if desired four or more suction motors could be provided surrounding the suction outlet in plan and wherein at least one pair of suction, motors are substantially opposed to each other in plan and ^' each suction motor being located in an associated side wall of the housing.

As stated above each impeller of the suction motors is located within or more suitably adjacent the internal chamber. The exhaus -port of each suction motor therefore suitably extends outwardly from the housing. The aforementioned suction apparatus could be advantageously incorporated in a vacuum cleaning device used for cleaning of carpet, upholstery, curtains and the like.

The vacuum cleaning device may include an internal compartment; a receptacle optionally mounted in the internal compartment; an inlet port and wherein the suction apparatus is releasably mounted within the vacuum cleaning device by appropriate mounting means.

The vacuum cleaning device as described above may include a casing which may also have any suitable shape such as being cylindrical, cuboidal or in the form of a polyhedron. However suitably the casing is cylindrical and is divided into separate compartments which include the

aforementioned internal compartment containing the receptacle; a compartment which may optionally be present containing water and/or treatment chemical and another suction compartment for inclusion of the aforesaid suction

5 apparatus.

Preferably the internal compartment includes a cover which is releasably attachable to the casing and which may have associated therewith a guide tube for retention of an air- hose for conveying air or air entrained water

10 droplets and dirt from the carpet. In this arrangement the air hose may communicate with a suction head or carpet tool. The internal chamber is preferably non circular in shape and is suitably polygonal in cross section. Preferably the internal chamber is hexagonal in cross

15 section.

The receptacle may comprise a bucket or other suitable container for collection of the material taken from the carpet by the air hose. The receptacle may be retained within the internal chamber in any suitable manner.

2 The compartment for containing treatment chemical and/or water may also suitably accommodate a suitable container and may also be provided with an exit tube associated with a pump ^' for conveying treatment chemical suitably mixed with water to an outlet located on an

-, _c external surface of the housing which may be attached to a water hose for conveying water and/or treatment chemical to the suction head.

However it is emphasised that the cleaning device including the suction apparatus of the invention may also only operate as a suction or vacuum device and thus the aforementioned compartment for containing water and/or treatment chemical may be dispensed with.

Reference may now be made to a preferred embodiment of the invention as shown in the attached drawings wherein:

FIG 1 is a rear view of a carpet cleaning device or machine constructed in accordance with the invention with a ι _Q rear wall removed for clarity;

FIG 2 is a schematic side view of the machine shown in FIG 1;

FIG 2A is an.exploded view of the filter means used for'the suction motors; •, e FIG 3 is a view of the suction apparatus supported . by a mobile frame removable from the housing of the machine shown in FIG 1;

FIG 4 is a top plan view of the machine shown in FIG 1;

20 FIG 5 is a perspective view of an alternative form of suction apparatus to that shown in FIG 3;

FIG 6 is a side view of the suction apparatus shown in FIG 5;

FIG 7 is an exploded perspective view of the suction apparatus shown in FIG 5;

FIGS 8 to 10 are perspective views of a carpet cleaning head for use with the machine of FIG 1;

FIG 11 is a perspective view of a modified form of suction apparatus for use in the invention;

FIG 12 is a perspective view of a cleaning head incorporating suction apparatus in accordance with the 5 invention;

FIG 13 is an exploded perspective view of the cleaning head shown in FIG 12; and

FIG 14 is a schematic view of the cleaning head shown in FIG 12. 1.0 In the drawings and in particular in FIGS 1-2 there is shown machine housing 10 having suction apparatus or vacuum pump assembly mounted therein in compartment or recess 12. The suction, apparatus comprises an inlet tube 13 which is in communication with internal chamber 14. Tube 13 5is engaged by sleeve or guide collar 15A which communicates with inlet port 16. The suction apparatus 11 comprises motors 17, impeller housings 18 and cooling vents 19. Each impeller 20 surrounds or is located on the periphery of inlet chamber 21 in opposed relationship.- o Suitably the suction apparatus 11. is mounted on a mobile frame 22. The housing also is suitably mobile having ground engaging wheels (not shown) . Frame 22 may be easily removed from recess 12 by unscrewing bolts 24 as shown.

In FIG 2 there is shown internal chamber 14 having 5 receptacle 15. Chamber 21 as shown is in fluid communication with inlet port 16 as well as internal chamber

14. Also shown is removable cover 24 mounted in recess 25 which has guide tube 26 for attachment to an air hose. Also shown is compartment 27 which contains water and/or treatment chemical. Conduit 28 communicates with compartment 27 as shown and is associated with pump 29. Conduit 28 also includes an external fitting 30 for attachment to a water hose. Also shown is detachable cover 21 and filter 31A which preferably is a mesh or perforated plate 29A mounted to a carrier disc 29B as shown in FIG 2A. 0 In FIG 3 there is shown mobile frame 22 for suction apparatus 11 in more detail removed from installation within housing 10. The frame 22 includes horizontal frame members 32 and brackets 33 interconnecting suction apparatus 11 to frame members 32. Also shown are vertical frame members 34

_T eas well as attachment brackets 35 to housing 10 which may be attached by bolts 24.

In FIG 4 there is shown a top plan view of housing 11 comprising inlet 36 for tank 27 having a cover 37. Also shown is a cross section view of chamber 14 which is -^hexagonal as well as mounting recess 25 for cover 24 which is circular as shown.

In FIGS 5-7 there is shown alternative suction apparatus 11A comprising a housing 37A, inlet tube 39, inlet chamber 38, inlet pipe retaining collar 39A and holding ^rackets 40. There are shown three motors 17 with associated impeller housing 18 and exhaust ports 23A. The chamber 38 is hexagonal in shape as best shown in FIG 6 having walls 41.

• It is preferred for inlet chambers 21 and 38 to be non circular such as being triangular, rectangular or polygonal as described before for inlet chamber 14.

In FIG 7 there are shown mounting apertures 42 for motors 17 as well as partitions 43 forming the walls 41 of housing 37A.

FIGS 8-10 show detailed views of the cleaning head or tool for use with the present invention. There is shown handle 44, cleaning head 45 and valve assembly 46 for 0directing flow of treatment chemical onto a carpet. Valve assembly 46 includes retaining collar 47 for attachment to handle 44, water hose 48 which is attached to external fitting 30 and couplin assembly 49 interconnecting valve assembly 46 and hose 481 There is also shown actuating 5trigger 50 which in use moves valve stem 51 away from valve passage 52 to allow treatment chemical/water to travel down conduit 52 to cleaning head 45 and exit therefrom through jets 53. Handle 44 is attached to cleaning head 45 by bracket 54. Also shown is brush 55 and vacuum inlet slot 56 ofor air to be drawn through to housing 10. In use jets 53 spray treatment chemical onto the carpet in advance of slot 56 during travel of head 45 over the carpet. ^' In another aspect of the invention the cleaning head 45 also may have a suction assembly associated therewith. In one possible arrangement a mobile frame 22 together- with associated double motors 17 as shown in FIG 3 may be mounted in end walls 57A of cleaning head 45 or if desired in side walls

58A. However location in end walls 57A is more convenient. In another possible arrangement the motor assembly as shown in FIGS 5-7 may be associated with cleaning head 45 to assist, suction and thus efficient extraction of water and dirt from the carpet.

In FIG 11 there is shown another form of mounting means for suction apparatus 11. This includes mounting frame 22A having base platform 60 and mounting plates 61. Also shown are attachment apertures 62 for attachment to housing 10. The provision of mounting frame 22A provides a portable or transportable means for suction apparatus 11.

In FIG 12 there is shown a cleaning head 63 including a suction assembly in accordance with the invention including cap 65 releasably attached to cleaning head 63 and also mobile wheels 64. ^■ '

FIG 13 shows the mounting of suction apparatus 11 within cleaning head 63 using mounting frame 22A. Twin exhausts 66 are shown for exhausting of hot exhaust air into front flue 67. The rear flue 68 is provided for vacuum cleaning of a carpet or the like. A vacuum chamber 69 is also provided which is attached to handle 44. Hose 48 is attached to mating connectors 70 and 70A to spray bar 71 which has spray nozzles 58. Spray bar 71 is located in spray housing 72. .Suction or vacuum chamber 69 is also provided with opposed conduits 73. The rear conduit 73 is attached to handle tube 44.

The operation of the apparatus shown in FIG 13 is

. illustrated schematically in FIG 14. A carpet (not shown) is cleaned by the application of steam or spray optionally containing treatment chemical through nozzles 58. Drying may be achieved by hot exhaust air being applied to the carpet

5through front flue 67. Front conduit 73 attaches to aperture 74 in cover 75 and exhaust conduits 66 communicate through apertures 76. The dirt or other impurities in the carpet are drawn through rear flue 68 and into vacuum chamber 69. Vacuum air may be exhausted through outlet 78 l§>f handle 44 which is attached to hose 77 which in turn is attached to guide tube 26 of machine housing 10. The twin exhausts 66 include enlarged tube 66A and smaller tube 66B. Also shown is ^' brush 79 which is an optional attachment as well as power cord 80.

15 The opposed relationship of suction motors 17 in FIG 1 or substantially opposed relationship of suction motors 17 shown in FIG 6 surrounding the suction outlet 13 or 39 means that "dead spots" will not occur in the housing 11 or 11A and that unlike the prior art shown in U.S. Patent

-4,202,070 there is much shorter path length between impellers 18 and inlets 13 or 39. This gives rise to a steeper pressure gradient than is the case with the prior art. This provides the advantage of ^" greater depression at inlets 13 or 39 in response to obstruction of the airflow, extraction efficiency.

In another embodiment the attachment of cleaning

head 63 to machine housing 10 through connecting hose 77 may be dispensed with and cleaning head 63 used individually. In this arrangement vacuum chamber 69 may act as a suitable receptacle for dirt and other impurities. It will also be appreciated that the suction apparatus of the invention can also be installed in fixed cleaning devices or systems operating on a vacuum principle such as car washing systems which are built permanently into a garage or the like or cleaning systems installed in buildings with a plurality of ducts built into the walls of the building. The suction apparatus may also be installed in street cleaning systems operating on a vacuum principle.

It will also -be appreciated that the suction outlet for the suction apparatus of the invention may comprise a tube or aperture. Preferably however there is provided an ^" outlet tube extending outwardly from the housing.

The filter means 31A as described above in the embodiment of FIGS 11-13 may be included as shown in the conduit formed by mating tubular members 81 and 82 between housing 11 and vacuum compartment 69.