Abstract:
A surface cleaning apparatus comprises a fluid delivery system including a supply of cleaning fluid stored in a fluid supply chamber and a fluid recovery system for drawing dirty cleaning fluid using suction from the surface to be cleaned. The apparatus has an inline fluid heater having a metal body with an embedded heating element and a polymeric cover provided with a fluid inlet fitting and a fluid outlet fitting. The fluid inlet and fluid outlet fittings are preferably integrally molded with the polymeric cover.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of Ser. No. 12/346,256, filed Dec. 30, 2008, which is a divisional application of Ser. No. 11/276,167, filed Feb. 16, 2006, which claims the benefit of U.S. Provisional Patent Application No. 60/593,829, filed Feb. 17, 2005, and U.S. Provisional Patent Application No. 60/743,153, filed Jan. 20, 2006, all of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a surface cleaning apparatus that fluid cleaning system to deliver heated cleaning fluid to a surface to be cleaned. In one of its aspects, the invention relates to a surface cleaning apparatus that has an inline heater to heat cleaning fluid. 
         [0004]    2. Description of the Related Art 
         [0005]    Extractors are well-known devices for deep cleaning carpets and other fabric surfaces, such as upholstery. Most carpet extractors comprise a fluid delivery system and a fluid recovery system. The fluid delivery system typically includes one or more fluid supply tanks for storing a supply of cleaning fluid, a fluid distributor for applying the cleaning fluid to the surface to be cleaned, and a fluid supply conduit for delivering the cleaning fluid from the fluid supply tank to the fluid distributor. The fluid recovery system usually comprises a recovery tank, a nozzle adjacent the surface to be cleaned and in fluid communication with the recovery tank through a working air conduit, and a source of suction in fluid communication with the working air conduit to draw the cleaning fluid from the surface to be cleaned and through the nozzle and the working air conduit to the recovery tank. An example of an extractor is disclosed in commonly assigned U.S. Pat. No. 6,131,237 to Kasper et al., which is incorporated herein by reference in its entirety. The Kasper et al. &#39;237 includes an aluminum body that includes a cover made of aluminum and further includes a fluid inlet fitting and a fluid outlet fitting connected to the metal body for circulating fluid through the metal body. Corrosion may be a problem resulting from casting the fluid inlet and fluid outlet fittings into the metal heater block. This problem might be overcome the use screw-in fittings with an O-ring rather than casting the fittings into the block. This solution may reduce the corrosion problem but may also add significant cost in that the block is required to be tapped and a hand assembly is required for threading the fittings into the tapped holes. Further, the metal cover may have to be Teflon coated to avoid corrosion problems. 
         [0006]    The U.S. Patent Application Publication No. 2004/0197095 to Thweatt, Jr. discloses a heater for fluids including a housing made of non-metallic material and having an internal cavity and an inlet and an outlet in fluid communication with the internal cavity. The heater housing is made of a polymeric material. A heating element is suspended within the cavity for heating fluid flowing therethrough. Further, the heating element comprises a U-shaped portion and electrical connectors at opposite ends of the heating element which extend through the housing. Thweatt, Jr. &#39;095 has fluid inlet and outlet fittings mounted to the heating element in an end wall of the plastic housing. The heating element may melt the walls of the plastic housing when the housing is dry, regardless of the existence of a thermal cutoff control. 
       SUMMARY OF THE INVENTION 
       [0007]    A surface cleaning apparatus according to the invention comprises a housing, a fluid delivery system mounted to the housing and including a fluid supply chamber for holding a supply of cleaning fluid, a fluid dispenser for applying cleaning fluid from the fluid supply chamber to the surface to be cleaned, and a fluid supply conduit between the fluid supply chamber and the fluid dispenser. The apparatus further comprises a fluid recovery system mounted to the housing and including a suction nozzle and a vacuum source in fluid communication with the suction nozzle to draw dispensed fluid from the surface to be cleaned through the suction nozzle. 
         [0008]    According to one embodiment of the invention, the apparatus further comprises an in-line fluid heater comprising a metal body with an embedded heating element and a polymeric cover with a fluid inlet fitting and a fluid outlet fitting connected in-line with the fluid supply conduit. 
         [0009]    In another embodiment of the invention, the fluid inlet and outlet fittings of the heater are integrally molded with the cover. 
         [0010]    In yet another embodiment of the invention, the metal body of the heater forms a fluid channel having an open upper end, and the cover closes the open upper end of the fluid channel to form a closed fluid channel in the fluid heater. 
         [0011]    According to yet another embodiment of the invention, the heater cover is secured to the body of the heater with mechanical fasteners and a gasket located between the cover and the body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    In the drawings: 
           [0013]      FIG. 1  is a rear, left perspective view of an extractor according to the invention with a handle assembly pivotally mounted to a foot assembly. 
           [0014]      FIG. 2  is a schematic view of a fluid delivery system for the extractor of  FIG. 1 . 
           [0015]      FIG. 3  is a top view of a heater for use with the fluid delivery system of  FIG. 2 . 
           [0016]      FIG. 4  is a sectional view taken along line  4 - 4  of  FIG. 3 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    Referring now to the drawings and particularly to  FIG. 1 , an upright extractor  10  according to the invention comprises a housing having a foot assembly  12  for movement across a surface to be cleaned and a handle assembly  14  pivotally mounted to a rearward portion of the foot assembly  12  for directing the foot assembly  12  across the surface to be cleaned. The extractor  10  includes a fluid delivery system for storing cleaning fluid and delivering the cleaning fluid to the surface to be cleaned and a fluid recovery system for removing the spent cleaning fluid and dirt from the surface to be cleaned and storing the spent cleaning fluid and dirt. The components of the fluid delivery system and the fluid recovery system are supported by at least one of the foot assembly  12  and the handle assembly  14 . Details of the extractor  10  are more fully described in parent U.S. Patent Application Publication No. 2009/0101187, filed Dec. 30, 2008, entitled “Surface Cleaning Apparatus with Cleaning Fluid Supply”, which is incorporated herein by reference in its entirety. 
         [0018]    The foot assembly  12  comprises a base assembly  20  that supports a recovery tank assembly  22  at a forward portion thereof and a solution supply tank assembly  24  at a rearward portion thereof. Further, a nozzle assembly  340  is removably mounted to a forward portion of the base assembly  20 . 
         [0019]    Referring to  FIGS. 1 and 2 , the extractor  10  comprises the fluid recovery system for removing the spent cleaning fluid and dirt from the surface to be cleaned and storing the spent cleaning fluid and dirt. The nozzle assembly  340  forms a portion of the fluid flow path, the opening of which is positioned adjacent a surface to be cleaned. When the nozzle assembly  340  and the recovery tank assembly  22  are mounted to the base assembly  20 , a continuous working air path is formed through the nozzle assembly  340  and the recovery tank assembly  22 . A vacuum is drawn on the recovery tank assembly  22  and nozzle assembly  340  by a motor and fan assembly  228  to draw spend cleaning fluid from the surface to be cleaned. 
         [0020]    The solution supply tank assembly  24  is removably mounted to the base assembly  20 . The solution supply tank assembly  24  comprises a solution supply tank housing  150  that defines a solution supply chamber (not shown). The solution supply tank housing has outlet  156  in a bottom wall thereof. The outlet  156  receives a valve mechanism  158  for controlling flow of fluid from the solution supply chamber  152 . Spray tips  218  are in fluid communication with solution supply chamber  152  so that the fluid can be supplied from the spray tips  218  to the surface to be cleaned. 
         [0021]    As mentioned above, the extractor  10  comprises the fluid delivery system for storing the cleaning fluid and delivering the cleaning fluid to the surface to be cleaned. For visual clarity, the various electrical and fluid connections within the fluid delivery system are not shown in the drawings described above but are depicted schematically in  FIG. 2 . Referring now to  FIG. 2 , the fluid delivery system comprises a bladder  44  for storing a first cleaning fluid and the solution supply tank housing  150  of the solution supply tank assembly  24  for storing a second cleaning fluid. The first and second cleaning fluids are dispensed from the bladder  44  and the solution supply tank housing  150  through respective valve mechanisms  48 ,  158 , which are received by respective valve seats (not shown) when the recovery tank assembly  22  and the solution supply tank assembly  24 , respectively, are mounted to the base assembly  20 . The first cleaning fluid flows from the bladder  44  and through a heater  680 , which heats the first cleaning fluid when the heater  680  is activated through a heater switch  388 , to a mixing manifold  510 . The mixing manifold  510  forms a conduit for the first cleaning fluid between a first fluid inlet  510 A and an outlet  510 B and also includes two second cleaning fluid inlets  510 C,  510 D. The second cleaning fluid inlets  510 C,  510 D fluidly communicate with the conduit for the first cleaning fluid in a mixing chamber  510 E. The heater  680  can heat fluids and is preferably an in-line heater. Exemplary valve mechanisms and heaters are disclosed in U.S. Pat. No. 6,131,237 and U.S. patent application Ser. No. 60/521,693, which are incorporated herein by reference in their entirety. 
         [0022]    In operation, when a user depresses a fluid trigger  460  on the handle assembly  14 , a trigger switch  462  opens a spray tip valve  224  to deliver cleaning fluid to the spray tips  218  for dispensation onto the surface to be cleaned. 
         [0023]    The heater  680  for heating the cleaning fluid is illustrated in  FIGS. 3 and 4 . The heater  680  is similar to the heater disclosed in the aforementioned and incorporated U.S. Pat. No. 6,131,237 in that the heater  680  comprises a metallic body  682 , such as an aluminum body, that forms a serpentine fluid channel  684  with an open upper end and houses a heating element  686 . The heater  680  further comprises a polymeric cover  688  mounted to the body  682  by mechanical fasteners  690 , such as screws, with a gasket  692  therebetween. The cover  688  comprises a fluid inlet port  694  and a fluid outlet port  696 , which are preferably integrally molded with the cover  688 . When the cover  688  is mounted to the body  682 , the cover  688  closes the open upper end of the fluid channel  684 , and the fluid inlet port  694  and the fluid outlet port  696  provide an inlet and an outlet, respectively, to the fluid channel  684 . During operation, the cleaning fluid flows through the fluid inlet port  694  into the fluid channel  684  and exits the fluid channel  684  through the fluid outlet port  696 . As the cleaning fluid flows through the fluid channel  684 , heat from the heating element  686  conducts through the body  682  and to the cleaning fluid to thereby heat the cleaning fluid. 
         [0024]    The hybrid heater  680  according to the invention uses a metal block (body  682 ) with an embedded heating element  686  for efficient heat transfer but eliminates a metal cover and integrally forms the inlet and outlet ports  694 ,  696  with the plastic cover  688 . Thus, the invention avoids the corrosion problems of the prior art while maintaining the heat transfer properties of the prior art and eliminates expensive machining operations, hand assembly and Teflon coating of the cover. The metal body  682  with the embedded heating element  686  stores heat energy and gives a thermal sensor the time to react. Thus, the invention involves the combination of a plastic cover that mounts the inlet and outlet ports  694 ,  696 , preferably by integral molding. 
         [0025]    The various features of the extractor  10  described here are not limited for use in an upright extractor. Rather, the features can be employed for any suitable surface cleaning apparatus, including, but not limited to, hand-held extractors, canister extractors, upright and canister vacuum cleaners, shampooing machines, mops, bare floor cleaners, and the like. 
         [0026]    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. Reasonable variation and modification are possible within the scope of the forgoing description and drawings without departing from the spirit of the invention which is defined in the appended claims.