Patent Publication Number: US-8117713-B2

Title: Vacuum cleaner with two stage filtration

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional application Ser. No. 60/596,446, filed Sep. 23, 2005, which is incorporated herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to vacuum cleaners. In one of its aspects, the invention relates to a vacuum cleaner having two stages of filtration. In another of its aspects, the invention relates to an extraction cleaner that has two stages of filtration. In yet another of its aspects, the invention relates to a multiple use vacuum cleaner that is adapted for dry vacuuming, extraction, and bare floor cleaning. 
     2. Description of the Related Art 
     Vacuum cleaners are well-known household cleaning devices that are used to clean dirt and debris from rugs and carpets. Vacuum cleaners commonly use a motor-driven suction fan to draw dirt-laden air into the unit, filter the air through some filtering means and exhaust the relatively clean air back into the room. One type of filtering means is a filter bag, wherein dirt-laden air is drawn into a porous bag which traps dirt and allows relatively clean air to exit through the walls of the bag to the environment as disclosed in U.S. Pat. No. 5,544,385 to Jailor et al. However, fine dirt particles can escape through the walls of the bag, thus recontaminating a room. Also, bags must be changed regularly when they are full, which is a time-consuming operation and requires a user to have a supply of new filter bags at hand, which adds additional expense to a vacuum cleaner. Changing filter bags is often a messy operation during which some of the collected dirt can become reentrained in the environment of a room. 
     An alternative to vacuum cleaners having filter bags as a filtering means are bagless vacuum cleaners which use cyclonic separators to separate dirt from the air using centrifugal force as disclosed in U.S. Pat. No. 4,571,772 to Dyson. Dirt-laden air is introduced into a cyclone separator, usually through a tangential opening near the top of the separator, and flows through the separator in a well-established cyclonic pattern. Dirt is separated from the air and is thrown outwardly against the walls of the separator where it falls down into a collection chamber. Relatively clean air then exits the separator and is exhausted to the environment. As with a bagged vacuum cleaner, this exhausted air may still contain fine dirt particles that were not filtered out in the cyclonic separator. And while the collection chamber for a cyclonic vacuum cleaner can be removed from the vacuum cleaner and emptied with relative ease compared to the changing of a filter bag, the dumping operation can also allow dirt particles to be reentrained in the air. 
     A third type of filtering means is the use of a water bath to remove dirt from air flowing through a vacuum cleaner as disclosed in U.S. Pat. No. 4,251,241 to Bothun. Dirt-laden air that is drawn in by the suction fan is ported through an air inlet such that it is directed through a reservoir of water. Heavier dirt particles are captured by the water while the filtered air exits the water bath and is exhausted to the environment. The reservoir of water may be a detachable chamber to facilitate disposal of the dirty water after vacuum cleaning. Emptying the reservoir of dirty water is more hygienic in comparison to changing filter bags or emptying a collection chamber filled with dry dirt, since the dirty water can be poured into a sink or drain without any particle reentrainment into the environment as is observed when pouring out dry dirt. 
     Even with regular vacuum cleaning, carpets often require more intense cleaning to remove stains or dirt that is deeply ingrained into the carpet pile. One way of deep cleaning a carpet is referred to as wet extraction and can be accomplished distributing a cleaning solution over the carpet and removing the spent cleaning solution by vacuum suction. Many homeowners choose to have this done professionally since they do not have the necessary equipment for deep cleaning a carpet or do not want to purchase a wet extraction machine that will only be used a few times a year. Some vacuum cleaners can be converted into a wet extraction cleaner to combine the functions of dry vacuuming and carpet deep cleaning as disclosed in U.S. Pat. No. 5,287,590 to Yonkers et al. These devices often have many complicated parts that must be interchanged in order to perform each function. 
     Many homes include bare floors such as linoleum, tile, or hardwood in addition to carpeted surfaces. Most homeowners have vacuum cleaners, whether bagged, bagless, or water-filtered, that are adapted for carpeted surfaces and may damage bare floors, thus additional cleaning devices are required. Bare floors commonly require multiple implements in order to achieve a thoroughly clean surface. Usually, a broom and dustpan are first used to gather and remove loose, dry particles from the floor. However, it is almost impossible to transfer all the dirt onto a dustpan and consequently, some dirt remains on the floor. After sweeping, a cleaning liquid is applied to the floor, most commonly by a sponge or rag mop. A mop is a very efficient cleaning means but when it requires more cleaning solution, the mop must be returned to a bucket to absorb additional cleaning solution to be reapplied to the floor surface. The repeated dipping of the mop into the bucket quickly dirties and cools the cleaning solution rendering the cleaning process less effective. After mopping, some cleaning solution remains on the floor surface to air dry, and the duration of time required for the bare surface to completely dry depends on the amount of residual solution on the floor and the relative humidity in the room. During the drying period, foot traffic must be avoided since dirt and other debris will easily adhere to the damp floor surface. 
     Some household cleaning devices have been developed that combine carpet dry vacuuming and deep cleaning with bare floor cleaning to eliminate the need for multiple cleaning devices for different types of cleaning. These cleaning devices are referred to as wet/dry vacuum cleaners or three-in-one cleaners. Many of these combined cleaners require disassembling the unit or changing certain parts such as filter or collection means to switch between cleaning types. For example, U.S. Pat. No. 4,287,636 to Brazier discloses a vacuum cleaner that can be used for both dry vacuuming and wet extraction. However, a filter unit for dry vacuuming must be exchanged for a reservoir unit when a user desires to use the vacuum cleaner for extraction. 
     The present invention solves the aforementioned problems by providing a single cleaning machine with a water bath filter in combination with a cyclone separator that can be used on both carpet and bare floors for both dry and wet pickup. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, a combination wet-dry vacuum cleaner comprises a recovery tank adapted for both wet and dry cleaning that is fluidly connected to a suction nozzle, the recovery tank having an air-liquid separator, a cyclone separator that is fluidly connected to an outlet in the recovery tank, and a suction source that is fluidly connected to the suction nozzle through the recovery tank and the cyclone separator to draw dry dirt-laden air and liquid-laden air from the suction nozzle through the recovery tank and the cyclone separator. During dry cleaning, the dry dirt-laden air is filtered with a water bath. During wet cleaning, the liquid-laden air is separated in the air-liquid separator in the recovery tank and the cyclone separator. Any liquid remaining in the air is recovered before the air enters the suction source. 
     The vacuum cleaner can further comprise a diverter valve between the suction nozzle and the recovery tank for directing the liquid-laden air to the air-liquid separator and for alternatively directing the dry dirt-laden air to the recovery tank. 
     The recovery tank can further comprise a conduit to pass dry dirt-laden air into a lower portion of the recovery tank as it enters the recovery tank so that the dry dirt-laden air can be filtered in the water bath in the recovery tank. 
     The recovery tank can further comprise a lower portion and an upper portion, wherein the upper portion is selectively removable from the lower portion and the upper and lower portions are separated by seals, and wherein the upper and lower portions are shaped so that the seals are above the maximum fill level of water in the recovery tank. 
     In accordance with another embodiment of the invention, a combination wet-dry vacuum cleaner comprises a recovery tank that is connected to a suction nozzle, a first air-liquid separator in the recovery tank for separating air from liquid from the suction nozzle when an air-liquid mixture enters the recovery tank; a second separator that is connected to an outlet in the recovery tank to remove liquid from air before it passes from the recovery tank; and a suction source that is connected to the suction nozzle through the recovery tank and the second separator to draw dry dirt-laden air and liquid-laden air from the suction nozzle through the recovery tank and the cyclone separator. The recovery tank is thus adapted for both wet and dry cleaning, the dry dirt-laden air is filtered with a water bath for dry cleaning and the liquid-laden air is separated in the air-liquid separator in the recovery tank and the second separator for wet cleaning. Thus, any remaining liquid in the air is recovered before entering the suction source. 
     In one embodiment, a diverter valve is positioned between the suction nozzle and the recovery tank for directing the liquid-laden air to the air-liquid separator and for directing the dry dirt-laden air into a water bath in the recovery tank. In a preferred embodiment of the invention, the recovery tank further comprises a conduit to pass dry dirt-laden air into a lower portion of the recovery tank as it enters the recovery tank so that the dry dirt-laden air can be filtered in the water bath in the recovery tank. 
     In accordance with still another embodiment of the invention, a combination wet-dry vacuum cleaner comprises a recovery tank that is connected to a suction nozzle, an air-liquid separator in the recovery tank for separating air from liquid from the suction nozzle, a diverter valve between the suction nozzle and the recovery tank for directing the liquid-laden air to the air-liquid separator and alternately for directing the dry dirt-laden air into a water bath in the recovery tank and a suction source that is connected to the suction nozzle through the recovery tank to draw dry dirt-laden air and liquid-laden air from the suction nozzle through the recovery tank and the cyclone separator. The recovery tank is thus adapted for both wet and dry cleaning, wherein the dry dirt-laden air is filtered with a water bath for dry cleaning and the liquid-laden air is separated in the air-liquid separator in the recovery tank. 
     According to another embodiment of the invention, a dry vacuuming nozzle comprises a nozzle housing, a brush rotatably mounted in the housing and at least a pair of wheels mounted in the housing wherein the wheels are connected to the brush to drive the brush about an axis of rotation when the wheels are rotated. 
     According to yet another embodiment of the invention, a canister vacuum cleaner having a housing and a glide mounted to an under surface of the housing is provided, wherein the glide comprises at least a partial spherical surface that is adapted to glide over a carpet surface to distribute the load over the carpet for easy movement. The glide can further be mounted to the housing for rotation about a vertical axis. 
     The canister vacuum cleaner can further comprise at least one wheel mounted to the glide and adapted to contact a bare floor surface when the canister moves along a bare floor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of a canister vacuum cleaner according to the invention. 
         FIG. 2  is a bottom view of the vacuum cleaner shown in  FIG. 1 . 
         FIG. 3  is an exploded perspective view of the vacuum cleaner shown in  FIG. 1 . 
         FIG. 4   a  is a front view of the base of the vacuum cleaner shown in  FIG. 3 . 
         FIG. 4   b  is a rear view of the base of the vacuum cleaner shown in  FIG. 3 . 
         FIG. 5  is an exploded view of a recovery tank of the vacuum cleaner of  FIG. 1 . 
         FIG. 6  is a perspective view of a cover, a diverter assembly, and a cyclone assembly of  FIG. 5 . 
         FIG. 7  is a top quarter perspective view of the cyclone assembly of  FIG. 6 . 
         FIG. 8  is a top quarter perspective view of a bottom portion of the recovery tank of  FIG. 5  with the side walls removed for clarity. 
         FIG. 9  is a top view of the bottom portion of the recovery tank of  FIG. 8  with the upper portion of the recovery tank removed. 
         FIG. 10  is a partial sectional view taken along line  10 - 10  of  FIG. 2 . 
         FIG. 11  is a partial sectional view taken along line  11 - 11  of  FIG. 2 . 
         FIG. 12  is an exploded view of the base assembly of the vacuum cleaner of  FIG. 1 . 
         FIG. 13  is a top quarter perspective view of a clean solution tank of  FIG. 1 . 
         FIG. 14  is a schematic representation of a second embodiment of the clean solution tank of  FIG. 13  comprising an automatic solution mixer. 
         FIG. 15  is a perspective view of a tool caddy that can be attached to the vacuum cleaner of  FIG. 1  in place of the clean solution tank. 
         FIG. 16   a  is a top perspective view of a dry vacuuming nozzle that can be attached to the vacuum cleaner of  FIG. 1 . 
         FIG. 16   b  is a bottom perspective view of the dry vacuuming nozzle shown in  FIG. 16   a  with portions cut away to illustrated a geared brushroll. 
         FIG. 17   a  is a perspective view of a wet extraction nozzle that can be attached to a hose on the vacuum cleaner of  FIG. 1 . 
         FIG. 17   b  is a sectional view taken along line  17   b - 17   b  of  FIG. 17   a.    
         FIG. 18  is a is a perspective view of a bare floor nozzle that can be attached to the hose of the vacuum cleaner of  FIG. 1  and comprising wet and dry nozzle assemblies. 
         FIG. 19  is a side view of the bare floor nozzle of  FIG. 18 . 
         FIG. 20  is a sectional view taken along line  10 - 10  of  FIG. 2  showing a first portion of an air path through the vacuum cleaner of  FIG. 1  during dry vacuuming. 
         FIG. 21  is a sectional view taken along line  11 - 11  of  FIG. 2  showing a second portion of the path of an air path through the vacuum cleaner of  FIG. 1  during dry vacuuming. 
         FIG. 22  is a sectional view taken along line  10 - 10  of  FIG. 2  showing a first portion of an air/liquid path through the vacuum cleaner of  FIG. 1  during wet vacuuming. 
         FIG. 23  is a top quarter perspective view of the recovery tank of  FIG. 1  with a strainer attachment and a cover removed. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular to  FIGS. 1 and 2 , a canister vacuum cleaner  10  is described comprising a base  12 , a recovery tank  14 , a clean solution tank  18 , and a hose interface  20 . The vacuum cleaner  10  is mobile, with a pair of rear wheels  22 , and a front wheel assembly  24 . The front wheel assembly  24  consists of a glide ball  26  that is partially recessed into the base  12  and two bogey wheels  28  that rotate on an axle  30  mounted on a projection  32  extending from the glide ball  26 . On a carpeted surface, the glide ball  26  glides over the carpet pile for easy maneuvering. On a bare floor, the bogey wheels  28  engage the bare floor to maneuver the vacuum cleaner  10 . 
     The hose interface comprises a suction conduit  20   a  and a clean solution conduit  20   b . The clean solution conduit  20   b  is in fluid communication with the clean solution tank  18  to provide a path for transporting cleaning solution from the solution tank  18  to a commonly known fluid distributor (not shown) that distributes cleaning solution to a surface to be cleaned. A suitable fluid distributor is more fully described in U.S. Pat. No. 5,813,087 to Huffman which is incorporated herein by reference in its entirety. 
     A hose  16  is fluidly connected at one end to the hose interface  20  by a ¼ turn bayonet fastener and at the other end to a hollow grip  34 . The hose  16  comprises a suction conduit  16   a  in fluid communication with a wand  34   a  and the suction conduit  20   a  of the hose interface  20  to provide a path for dirt-laden air or water to move from a floor nozzle  284 ,  286 , or  288  to the recovery tank  14 , as will be described below. The hose  16  further comprises a clean solution conduit  16   b  in fluid communication with the clean solution conduit  20   b  of the hose interface. Optionally, the hose  16  and hose interface  20  can be swivelably connected to increase the ease of moving the canister vacuum cleaner  10  around a room. 
     The grip  34  comprises a hose receiving end  34   c  in fluid communication with the hose  16  and a wand receiving end  34   b  in fluid communication with a floor nozzle (dry vacuuming nozzle  284 , wet extraction nozzle  286 ) in a manner that will be discussed in more detail below. A hollow wand  34   a  is in fluid communication with and selectively detachable from the grip  34 . The grip  34  has a trigger assembly  35  that controls the distribution of cleaning solution to the surface to be cleaned. 
     Referring to  FIG. 3-4B , the base  12  comprises a bottom surface  36 , a back wall  38 , two opposing side walls  40 ,  42  and a curved front wall  44 . The wheels  22  are rotatably attached to the base  12  by axels  25  connected to a wheel housing  23  formed on the sides  40 ,  42  of the base  12 . A partition  46  extends vertically from the bottom surface  36  and horizontally from side wall  40  to side wall  42  and has an aperture  47  at a lower end. A first recess  48  is defined by the bottom surface  36 , the front wall  44 , the side walls  40 ,  42  and the partition  46 . A tube track  49  runs from the partition  46  across the bottom surface  36  of the first recess  48 . The tube track  49  receives a tube  260  that conveys cleaning solution from the clean solution tank  18  to the hose interface  20 . A second recess  50  is defined by the bottom surface  36 , the partition  46 , the side walls  40 ,  42  and the back wall  38 . A third recess  52  is defined by a wall  53  and extends from the first recess  48 , through the aperture  47 , and into the second recess  50 . The partition  46  further has a flat upper surface that functions as a handle  51  with an opening  58 . A corresponding recess  60  is formed in the clean solution tank  18  so that the user can carry that vacuum cleaner  10  when the tanks  14 ,  18  are in place on the base  12 . A cord wrap  54  is provided on the back wall  38  for wrapping an electrical cord (not shown) for storage. Commonly known electrical on/off switches  55  are located on the cord wrap  54  and can be actuated by a hand or foot of the user for controlling the actuation of a suction source and a fluid distribution mechanism. A removable exhaust grill  56  is located beneath the cord wrap  52  on the back wall  38 . 
     Referring to  FIGS. 5 and 6 , the recovery tank  14  has a bottom portion  80  comprising a back wall  82 , two opposing sidewalls  84 ,  86 , and a front wall  88 . A recessed portion  90  surrounds the hose interface  20  ( FIG. 3 ) and extends from the bottom portion  80 . A bumper  83  is attached to the front wall  88  to protect furniture from damage as the canister is moved about a room. A bumper reinforcement  85  is placed between the bumper  83  and the front wall  88  to stiffen the bumper. A transparent casing  81  is attached to the bottom portion  80  and comprises walls  82   a ,  84   a ,  86   a , and  88   a  that extend from walls  82 ,  84 ,  86 , and  88  of the bottom portion  80 . The recovery tank  14  is removably mounted to the base  12  such that it is received in the first recess  48  on the base  12  and the back wall  82  abuts the partition  46 . A removable cover  92  has a concave recess  93  that includes a bottom surface  95  with an aperture  97  and is positioned in the opening created by the upper edges of walls  82 ,  84 ,  86 , and  88 . The cover  92  is preferably made from a transparent material so that the contents of the recovery tank  14  can be viewed by the user. A screen  94 , a cyclone separator assembly  96 , and a diverter valve  108  are mounted to the underside of the cover  92  and removable therewith to provide clear access to the interior of the casing  81  when the cover  92  is removed. The clear space within the casing  81  facilitates easy emptying of the recovered contents. Three hollow stand conduits  150 ,  152 ,  154  extend vertically from the bottom wall  80  of the recovery tank  14 . The recovery tank  14  is adapted to hold a predetermined amount of water as a bath that serves as a first stage filtering means. 
     Referring to  FIG. 7 , the cyclone assembly  96  functions as a second stage filter and comprises an air inlet conduit  120 , a cyclone separator  122 , and an air outlet conduit  124 . Such cyclone assemblies are well-known in the dry vacuum cleaner art. A suitable cyclone separator is described in U.S. Pat. No. 4,571,772 to Dyson which is incorporated herein by reference in its entirety. The cyclone separator  122  has a hollow cylindrical portion  126  that is connected to a helical top wall  129  and to a truncated cone portion  128  with a debris opening  130 . The inlet conduit  120  is positioned tangentially to the cylindrical portion  126  in order to introduce the air into the cylindrical portion  126  tangentially along the inner wall surface of the cylindrical portion  126  to form a well-known cyclonic airflow pattern. The air outlet conduit  124  has a curved vertical end wall  132  that communicates with the interior of the cyclonic separator  122  through an exhaust tube  133  ( FIG. 10 ) in the top wall  129 , a pair of vertical side walls  138  and a curved end wall  134 . As mentioned above, the cyclone assembly  96  is joined to the cover  92  along the air outlet conduit  124 . Thus, the cyclone assembly  96  is removable with the cover and a separate lid is not required for the cyclone assembly  96 . 
     A shut-off valve  140  is hinged to the inlet conduit  120  and is operated by a float  141  to close the opening to the inlet conduit  120  to prevent water from entering the cyclone assembly  96 . As water in the recovery tank  14  rises, the float  141  will also rise and engage the shut-off valve such that the valve eventually swings upward to seal off the inlet conduit  120  to the cyclone assembly  96 . 
     The diverter valve  108  is cylindrical and comprises a top surface  110 , a side wall  112 , and an aperture  114  formed in the side wall  112  and has an outer diameter sized to engage the upper end of the diverter stand conduit  150 . A knob  116  is rotatably mounted to the bottom  95  through a pin  118  that extends through the aperture  97  and is non-rotatably connected to the diverter valve  108  through the pin  118 . The knob  116  is located on an upper external surface of the vacuum cleaner  10  so that the knob is easily accessible to the user. 
     The screen  94  is attached the underside of the cover  92  and is shaped such that the screen  94  covers substantially the bottom of the cover  92 . The screen  94  comprises a plurality of perforations and is formed with a first hole  100  that fits around the cyclone assembly  96 . A second hole  102  and an aperture  103  that is formed on one side of the screen  94  receives the stand conduits  154  and  150 , respectively when the cover is placed on the recovery tank. Although the vacuum cleaner  10  is most effective when a water bath filter is used, it can also be operated in a dry mode with an empty recovery tank. The screen  94  prevents large particles of dirt from entering the cyclone assembly  96 . 
     The vacuum cleaner  10  can selectively be switched between wet and dry vacuuming modes by rotation of the diverter valve  108  in relation to the stand conduit  150 . When the diverter valve  108  is in an “open position” used for wet vacuuming, the aperture  114  is oriented toward the front of the vacuum cleaner  10 . When the diverter valve  108  is in a “closed position” used for dry vacuuming the sidewall  112  is oriented toward the front of the vacuum cleaner  10  so that working air is forced down the standpipe  150  into a water bath. The external diverter knob  116  is connected to the diverter valve  108  so that a user can rotate the diverter valve  108  between the wet and dry vacuuming positions. Markings can be included on the bottom surface  95  to indicate the selected mode to the user. 
     Referring to  FIGS. 8 and 9 , a first rib  191  connects the diverter stand conduit  150  to the debris stand conduit  152  and a second rib  192  connects the debris stand conduit  152  to the back wall  82 . A deflector plate  190  extends horizontally from the diverter stand conduit  150  and the debris stand conduit  152  above a water bath inlet opening  168  formed near the bottom of the diverter stand conduit  150 . This deflector plate  190  controls the water spray that is created when the air impinges on the water surface and enters into the water bath  78 . 
     Referring to  FIG. 10 , the diverter stand conduit  150  is cylindrical in shape with an upper edge  156  that is received by the diverter valve  108  and has a wall  160  that divides the interior of the stand conduit into a first conduit  162  and a second conduit  164  The first conduit  162  communicates with an L-shaped conduit  166  that extends to the hose interface  20  and the second conduit  164  communicates with the water bath via the water bath inlet opening  168  at the lower end of the stand conduit  150 . 
     The debris stand conduit  152  is a hollow cylinder that has an upper end  170  and a lower end  172 . The upper end  170  communicates with the debris opening  130  of the cyclone separator  122  such that dirt that is separated in the cyclone separator  122  will fall under force of gravity through the opening  130  and into the debris stand conduit  152 . 
     Referring to  FIG. 11 , the exhaust stand conduit  154  is a hollow cylinder with an upper end  176  and a lower end  178 . The upper end  176  is dimensioned to fit within the end wall  134  on the cyclone assembly  96  when the cover  92  is on the recovery tank  14 . The lower end  178  has an air outlet aperture  180  in communication with a working air conduit  182  leading to a suction source comprising a motor/fan assembly  210 . 
     A coarse filter  184  can be placed between the air outlet aperture  180  and the working air conduit  182 . This filter  184  is useful, as is the screen  94 , when operating the vacuum cleaner  10  with an empty (no water) recovery tank  14 . The course filter can be a conventional foam filter that traps particles passing therethrough to prevent damage to the motor/fan assembly  210 . 
     A seal  186  is mounted between the upper edge  156  of the diverter stand conduit  150  and lip  102  on the diverter cylindrical valve housing  94  and another seal  188  is mounted between the debris stand conduit  152  and the debris opening  130  on the cyclone separator  122 , respectively. Both seals  186 ,  188  are located above the maximum recommended water bath level in the recovery tank  14 . Effective seals are desired to prevent unwanted water and air leakage through the system that could reduce the effectiveness of the working air flow or mechanically damage the suction source. The working air components may be repeatedly connected and disconnected during the removal of the cover from the recovery tank to empty or fill the recovery tank, the seals may become susceptible to water leaks. Positioning the seals above the maximum recommended water bath height further minimizes air or water leaks during cleaning operations. 
     Referring to  FIG. 12 , the suction source assembly comprises an air inlet housing  200  having a wall  201  around the perimeter of the housing, a bottom surface  202  with a circular aperture  203 , a connecting conduit  204  extending from the wall  201  and having a cylindrical fitting  205 , and an exhaust conduit  206  depending from the wall  201  received in the third recess  52  on the base  12 . The cylindrical fitting  205  is received by the lower end  178  of the exhaust stand conduit  154  ( FIG. 11 ) that communicates with the air outlet aperture  180  to form a working air conduit  182  defined by connecting conduit  204  between air outlet aperture  180  and aperture  203  when the recovery tank  14  is in place on the base  12 . A sealing gasket  207  is located between the cylindrical fitting  205  and the lip  178 . The cylindrical wall  201  defines a cavity  208  and comprises an exhaust aperture  209  that communicates with the exhaust conduit  206 . 
     The vertically-oriented motor/fan assembly  210  comprises a motor assembly  212  and a fan assembly  214 . The fan assembly  214  sits in cavity  208  and is enclosed by a retaining cover  216 . A horizontal plate  217  extending from the cover  216  mates with the exhaust conduit  206  to form a horizontal wall of the conduit. A motor/fan assembly casing  218  encloses the entire suction source assembly. Sealing gaskets  220  and  222  are mounted between the bottom surface  202  and the fan assembly  214  and between the motor assembly  212  and the retaining ring  216 , respectively. A third gasket  224  is mounted between the motor assembly  212  and a motor cover  225  to reduce noise and vibration of the motor/fan assembly  210 . 
     A HEPA filter  226  is disposed between the exhaust aperture  209  and the exhaust grill  56 . The exhaust grill  56  is removable to provide access to the HEPA filter  226  to provide easy access for removal and cleaning or replacement as necessary. The vacuum cleaner  10  further comprises a pump  228  mounted in the base to move fluid from the clean solution tank  18  through an in-line heater (not shown) also mounted in the base that elevates the temperature of the cleaning solution and through the hose  16 . Separate switches for the pump  228  and the heater (not shown) can be provided. A steam generating apparatus can also be incorporated into the vacuum cleaner  10 . An example of such an apparatus is described more fully in the Sham U.S. Pat. No. 5,819,364 or the Baldacci U.S. Pat. No. 5,920,952, both of which are incorporated by reference in their entirety. 
     A cooling air housing  227  is mounted to the base  12  such that the housing  227  abuts casing  218  and includes back wall  38  and cord wrap  54 . The cooling air housing  227  further includes a plurality of hemispherical exhaust grills  230  that allow air used to cool the motor assembly  212  to pass therethrough. A coarse filter  232  for the motor cooling air is located in the airpath between the motor assembly  212  and the grills  230  to filter any remaining dirt out of the air before it is exhausted from the vacuum cleaner. Air gaps are formed between the exhaust grills  230  and the wheels  22  to allow exhaust air to exit the space around the wheels  22 . The filter  232  is sized to capture carbon dust particles that may enter the motor cooling air path. In an alternate embodiment, the motor cooling air can be directed into the working air path so that the motor cooling air intermingles with the vacuum working air and passes through the HEPA filter  226  before being exhausted to the environment. The alternate embodiment eliminates the need for multiple filters. 
     Referring to  FIG. 13 , the clean solution tank  18  comprises a commonly known integrally formed tank comprising a sloped top wall  244 . The clean solution tank  18  has a recess  256  shaped to complement the outer shape of the motor/fan assembly casing  218 . A commonly known check valve  258  is located on the bottom of the clean solution tank  18  that is received by a corresponding socket  229  ( FIG. 12 ) in the base  12  to open the valve  258  when the tank  18  is mounted on the base  12 . To fill the clean solution tank  18 , the user inverts the tank, removes the valve  258  and pours solution through the opening in the top wall  244 . Typically, the cleaning solution comprises a combination of water and detergent. A tube  260  conveys cleaning solution from the tank  18  through the heater (not shown) to the clean solution conduit  20   b  where the solution is distributed onto the floor to be cleaned by a floor nozzle. The tube  260  is held in place by the track  49 . 
     Referring to  FIG. 14 , an alternate embodiment for the clean solution tank  18  is illustrated that incorporates an automatic mixer to mix cleaning detergent and solution pumped from separate holding tanks to a distributor for application to a surface to be cleaned. The clean solution tank  18  is divided into a solution compartment  270  and a detergent compartment  272  by a dividing wall  274 . Two spring-loaded valves  258  in an outlet opening of the compartments  270  and  272  are biased to a closed position when the tank  18  is removed from the vacuum cleaner to control the flow of water and detergent into a mixing chamber  276  and valve  281  controls the flow of the mixed cleaning solution into a clean solution conduit  16   b  of the hose  16 . The valves  258  have female fittings  278  located on the tank  18 . Male fittings on the sockets  229  located on the vacuum cleaner base couple to the female fittings when the tank  18  is mounted on the vacuum cleaner to open the valves  258 . 
     Referring to  FIG. 15 , a tool caddy  282  can be placed on top of the motor/fan assembly casing  218  in lieu of the clean solution tank  18 . Since the clean solution tank  18  is not used during dry vacuum cleaning, it is convenient to have accessory tools readily available that can be attached to the hose  16  in place of a floor nozzle  286 ,  286 . This interchangeability reduces the size and weight of the vacuum cleaner  10  for cleaning operations since the clean solution tank  18  and the tool caddy  282  are interchangeable. The tool caddy  282  has substantially the same external side and lower shape as the clean solution tank  18  ( FIG. 13 ). Common features between the tool caddy  282  and the clean solution tank  18  are referred to with the same reference number bearing a prime symbol (′). The tool caddy  282  further comprises a handle  280  and multiple depressions  281  that are sized to receive the tools for convenient storage thereon such as a bristle brush  283   a , a crevice tool  283   b , an upholstery brush  283   c , and extension tubes  283   d.    
     Multiple floor nozzles  284 ,  286  are provided for attachment to the grip  34  or wand  34   a , wherein each nozzle  284 ,  286  is used for a different cleaning mode. A conventional dry vacuuming nozzle having a turbine-driven brushroll can be provided or, as shown in  FIGS. 16   a  and  16   b , a dry vacuuming nozzle  284  having a mechanical brushroll  300  can be provided. The nozzle  284  has a top enclosure  290  mounted on a frame  292  and has a connection conduit  294  that attaches to the wand receiving end  34   b  on the wand  34   a . A pair of wheels  302  are coupled to drive gears  296  that rotate when the wheels  302  turn due to friction between the wheels and the surface to be cleaned. The drive gears  296  mesh with driven gears  298  that are coupled to the brushroll  300  to transmit rotary motion from the drive gears  296  to the brushroll  300 . The wheels  302  and brushroll  300  rotate in the opposite direction such that as the dry vacuuming nozzle  284  is pushed forward, the wheels  302  rotate toward the user and the brushroll  300  rotates away from the user standing behind the nozzle. Alternately, as the nozzle  284  is pulled back, the wheels  302  and the brushroll  300  will rotate in the opposite direction. 
     Referring to  FIGS. 17   a  and  17   b , a commonly known wet extraction nozzle  286  comprises a plate  304  with a connection conduit  310  for connecting the hose  16  extending at an angle from the plate  304  wherein a suction opening  312  is formed in the plate  304 . A second connection conduit  314  for connecting the solution conduit  16   b  extends from the first surface  306  below the first connection conduit  310  and communicates with a hollow protrusion  316  that extends laterally from the first surface. The protrusion  316  and has multiple apertures  318  to distribute cleaning solution from the clean solution tank  18  onto a carpeted surface and bristles  319  to scrub the carpeted surface. A cover  320  mounts in spaced relation to the plate  304  creating a space  322  that forms a suction inlet  324 . The suction inlet  324  and space  322  allows dirty solution to be drawn into the suction conduit  16   a  of the hose  16  and returned to the recovery tank  14 . A wet extraction nozzle is more fully described in U.S. Pat. No. 4,333,203 to Yonkers which is incorporated herein by reference in its entirety. 
     Referring to  FIGS. 18 and 19 , a bare floor cleaning head  288  comprises a top enclosure  326  mounted to a frame  328  to define a cavity therebetween that houses several components of the bare floor cleaning head  288 . The frame  328  provides structural support for several of the nozzle components, such as a pivotable connector  330  for connecting to the grip  34  on hose  16 , wet and dry nozzle assemblies  332 ,  334  on opposite sides of the bare floor cleaning head  288  for suctioning wet and dry debris, respectively, from the surface to be cleaned, and an agitator assembly  338 . 
     Referring particularly to  FIG. 19 , rotation of the grip  34  between the first and second positions induces rotation of the pivotable connector  330 . When the handle is pivoted to the first position, the wet nozzle assembly  332  is raised off the surface to be cleaned. This configuration corresponds to a dry vacuuming operational mode for bare floor bare floor cleaning head  288  and is achieved when the grip  34 , which is connected to the pivotable connector  330 , rotates towards the wet nozzle assembly  332  to the first position (i.e., the handle position indicated by the number  1  in  FIG. 19 ). When the grip  34  is in the first position, the dry nozzle assembly  334  is in front of the wet nozzle assembly  332 . When the grip  34  rotates in the opposite direction to the second position (i.e., the handle position indicated by the number  2  in  FIG. 19 ), the wet nozzle assembly  332  is lowered and contacts the surface to be cleaned. When the grip  34  is in the second position, the wet nozzle assembly  332  is in front of the dry nozzle assembly  334 . This configuration corresponds to a wet cleaning mode of the bare floor cleaning head  288 . A suitable bare floor cleaning head is disclosed in PCT/US2004/026952 which is incorporated herein by reference in its entirety. 
     Referring to  FIGS. 20 and 21 , when the vacuum cleaner  10  is used in the dry vacuuming mode, the dry vacuuming nozzle  284  is attached to wand  34   a  and the diverter knob  116  is manually turned to the dry cleaning position. Turning the motor on/off switch  55  to the “on” position completes an electrical circuit from facility power, through a power cord, through the motor on/off switch  55  and the resultant current flow causes the motor/fan assembly  210  to rotate, create a working airflow shown by arrows from the fan assembly  214 , which lifts dirt from the surface being cleaned through dry vacuuming nozzle  284   a  and hose  16 . In the first stage of filtering, the dirt-laden air travels (as indicated by the solid arrows in  FIG. 20 ) through L-shaped conduit  166  that is in fluid communication with first conduit  162 . Since the diverter valve  108  is “closed” (i.e. turned so that the sidewall  112  is oriented toward the front of the vacuum cleaner  10 ), dirt-laden air is diverted into second conduit  164 . The dirt-laden air then passes through the water bath at the water bath inlet opening  168  in the second conduit  164 . Dirt and debris is captured by the water and moist clean air is drawn up through the water. The moist clean air is then drawn into the cyclone separator  122  through the air inlet conduit  120  where moisture and any entrained dirt is forced against the walls of the cyclone separator  122  by cyclonic airflow therethrough, thus separating the finer dirt particles that were not filtered by the water bath and any moisture from the water bath. The dirt particles and water fall through opening  130  and into the debris stand conduit  152 . Clean air exits the cyclone separator  122  up through the air outlet conduit  124  and then through the exhaust stand conduit  154  and air outlet aperture  180 . The cyclone separator exhaust air is drawn through the working air conduit  182  to the motor/fan assembly  210 . The working air is then exhausted from the motor/fan assembly  210  and exits the vacuum cleaner  10  through a commonly known HEPA filter  226 . The tool caddy  282  can be placed on the motor/fan assembly casing  218  so that the user can easily selectively access the accessory tools for specific cleaning needs. After cleaning is complete, the cover  92  is removed and set aside. The recovery tank casing  81  is removed from the base  12  and taken to a suitable location plumbed to accept waste water and debris. The recovery tank casing  81  is inverted to empty both the water and the debris in the debris stand conduit  152  simultaneously. 
     Dry vacuuming can also be performed with an empty recovery tank  14 . The air flow path through the vacuum cleaner  10  is the same, however, the first stage water bath filter is absent and the air is filtered by the screen  94  to remove larger dirt particles, the cyclone separator  122  for finer particles, and finally the optional coarse filter  184  before working air reaches the inlet to the motor/fan assembly  210 . 
     For bare floor cleaning, the vacuum cleaner  10  can be readied either with or without a water bath filtration stage and the bare floor cleaning head  288  is attached to the wand receiving end  34   b  of the wand  34   a . The wand  34   a  is maneuvered so that the bare floor cleaning head  288  is oriented in the first position with respect to the pivotable connector  330  ( FIG. 19 ) and the dry nozzle assembly  334  engages the floor surface. Airflow path through the vacuum cleaner  10  is as previously described. 
     Referring to  FIG. 22 , wet pickup can be accomplished by maneuvering the wand  34   a  so that the wet nozzle assembly  332  is facing forward as indicated in position  2  with respect to the pivotable connector  330 . In the wet pickup mode, the dry nozzle assembly  334  is raised and the wet nozzle assembly  332  engages the floor surface. A diverter valve (not shown) opens an air path to the wet nozzle assembly  332  and blocks an air path to the dry nozzle  326 . The clean solution tank  18  is filled with cleaning solution and secured on the motor/fan assembly casing  218 . The heater  260  may be turned on at any time during wet cleaning to heat or reheat the cleaning solution. The diverter knob  116  is turned to the wet vacuuming or “open” position. Clean solution is distributed to the floor by depressing the trigger  35 . The user then scrubs the floor surface with an agitator on a bottom surface of the bare floor cleaning head  288  to distribute the cleaning solution to a wider area and loosen dirt particles thereon. To pick up the dirty cleaning solution, the vacuum cleaner  10  is turned “on” and a working air/liquid flow is created as previously described, wherein the working airflow is shown with solid arrows. Since the diverter valve  108  is “open” (i.e. turned so that the aperture  114  is oriented toward the front of the vacuum cleaner  10 ), the working air is forced against the inner front wall of the recovery tank  14  which causes the liquid to separate from the air. The relatively dry air exits through apertures  100  and  114  and enters the cyclone assembly  96  through the inlet conduit  120  and follows the same working air path as previously described ( FIGS. 21 and 22 ). 
     Carpet cleaning is performed in a similar manner. The carpeted floor surface is first dry vacuumed as described above using the dry vacuuming nozzle  284 . The dry vacuuming nozzle  284  is then removed and the wet extraction nozzle  286  is attached to the wand  34   a . The clean solution tank  18  is filled with cleaning solution and placed on top of the motor cover  218 . The user depresses the trigger  35  to distribute cleaning solution onto the carpeted surface to be cleaned. Working air/liquid flow through the vacuum cleaner is as previously described. 
     When carpet extraction cleaning is complete, the recovery tank  14  is removed from the base  12  and the dirty water is disposed of in a suitable manner. A handle (not shown) may be attached to the recovery tank  14  to facilitate the process of disposing of the dirty water. Referring now to  FIG. 23 , some of the larger debris captured during the cleaning process can clog the plumbing system used for disposal, therefore an optional strainer  350  can be affixed to the side wall of the recovery tank  14  by clips  351 . The strainer  350  has a grid portion  352  that allows liquid and some smaller dirt particles to pass through the openings in the grid  352  and a handle  354  that can be gripped by a user when emptying the contents of the strainer  350 . The strainer  350  can optionally be carried on the tool caddy  282 . The dirty water in the recovery tank  14  can be poured through the strainer  350  to manually separate out the larger solid debris to prevent plumbing clogs. The debris captured in the strainer  350  can then easily be disposed in a solid waste receptacle such as a trash bin. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit. Reasonable variation and modification are possible within the foregoing disclosure and drawings without departing from the spirit of the invention.