Abstract:
The embodiments of the invention relate to methods of use of an extraction cleaning machine for cleaning a carpet segment of relatively rectangular configuration defined by a first edge, a second edge and opposite side edges comprising (a) applying a liquid cleaning solution to the carpet segment in a narrow band that extends between the side edges and moves between the first and second edges and (b) applying suction in a narrow band that extends between the side edges and moves between the first and second edges. Acts (a) and (b) can be repeated and performed in a predetermined sequence to improve the cleaning effectiveness of an extraction cleaning machine.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/587,934, filed Jan. 18, 2012, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Extraction cleaning machines are known for deep cleaning carpets and other fabric surfaces such as upholstery. Most carpet extractors comprise a fluid delivery system, a fluid recovery system, and, optionally, an agitation system. The fluid delivery system typically comprises one or more fluid supply tanks for storing cleaning fluid, a fluid distributor for applying the cleaning fluid to the surface to be cleaned, and a fluid supply conduit for supplying the fluid from the supply tank to the fluid distributor. The fluid recovery system typically comprises a recovery tank, a suction nozzle adjacent to the surface to be cleaned and in fluid communication with the recovery tank through a working air conduit, and a vacuum source in fluid communication with the working air conduit to draw cleaning fluid from the surface to be cleaned through the nozzle and working air conduit into the recovery tank. The agitation system can include an agitator element for scrubbing the surface to be cleaned, an optional drive means, and selective control means. The agitation system can include a fixed or driven agitator element that can comprise a brush, pad, sponge, cloth, and the like. The agitation system can also include driving and control means including motors, turbines, belts, gears, switches, sensors, and the like. See, for example, U.S. Pat. No. 6,131,237 to Kasper et al. and U.S. Pat. No. 7,073,226 to Lenkiewicz et al. 
       BRIEF SUMMARY 
       [0003]    According to an embodiment of the invention, a method of cleaning a carpet segment of relatively rectangular configuration defined by a first edge, a second edge and opposite side edges comprises: (a) applying a liquid cleaning solution to the carpet segment in a narrow band that extends between the side edges and moves between the first and second edges, (b) applying suction in a narrow band that extends between the side edges and moves between the first and second edges, (c) repeating act (a), and (d) repeating act (b). The acts (a), (b), (c) and (d) can be carried out successively with an end of a preceding act defining a beginning of a subsequent act. 
         [0004]    According to another embodiment of the invention, the movement of the cleaning solution narrow band in act (a) and the movement of the suction narrow band in act (b) are in opposite directions. 
         [0005]    In yet another embodiment, the method can further comprise mechanically agitating the carpet segment during movement of the suction narrow band in acts (b) and (d). 
         [0006]    In another embodiment, the method can further comprise heating the liquid cleaning solution prior to applying the liquid cleaning solution in acts (a) and (c). 
         [0007]    According to another embodiment of the invention, the acts (a) through (d) are carried out with an extraction machine. 
         [0008]    In yet another embodiment, a method of cleaning a carpet segment of relatively rectangular configuration defined by a first edge, a second edge and opposite side edges comprises: (a) applying a liquid cleaning solution to the carpet segment in a narrow band that extends between the side edges and moves between the first and second edges, (b) repeating act (a), (c) repeating act (a), and (d) applying suction in a narrow band that extends between the side edges and moves between the first and second edges. The acts (a), (b), (c) and (d) can be carried out successively with an end of a preceding act defining a beginning of a subsequent act. 
         [0009]    According to another embodiment of the invention, the movement of the cleaning solution narrow band in act (a) and the movement of the cleaning solution narrow band in act (b) are in opposite directions. 
         [0010]    According to another embodiment of the invention, the movement of the cleaning solution narrow band in act (a) and the movement of the cleaning solution narrow band in act (c) are in the same direction. 
         [0011]    According to another embodiment of the invention, the movement of the cleaning solution narrow band in act (a) and the movement of the suction narrow band in act (d) are in opposite directions. 
         [0012]    In yet another embodiment, the method can further comprise mechanically agitating the carpet segment during movement of the suction narrow band in act (d). 
         [0013]    In another embodiment, the method can further comprise heating the liquid cleaning solution prior to applying the liquid cleaning solution in acts (a), (b), and (c). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    In the drawings: 
           [0015]      FIG. 1  is a schematic of an extraction cleaning machine according to a first embodiment of the invention. 
           [0016]      FIG. 2  is a flowchart illustrating a method of use of an extraction cleaning machine according to a second embodiment of the invention 
           [0017]      FIG. 3  is a flowchart illustrating a method of use of an extraction cleaning machine according to a third embodiment of the invention. 
           [0018]      FIGS. 4-6  are charts illustrating average percent clean test results for three extraction cleaning systems according to an embodiment of the invention. 
           [0019]      FIGS. 7-9  are charts illustrating average Delta-E test results for three extraction cleaning systems according to an embodiment of the invention. 
           [0020]      FIG. 10  is a chart illustrating test results for an average amount of liquid retained by carpet cleaned with three different extraction cleaning systems according to an embodiment of the invention. 
           [0021]      FIGS. 11-12  are charts illustrating average percent clean test results for an extraction cleaning system using two different cleaning formulas according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The embodiments of the invention relate to methods of sequencing wet and dry strokes of an extraction cleaning machine, often referred to as an extractor or deep cleaner, for cleaning carpets and other soft surfaces. The methods can be used with any suitable extractor, non-limiting examples of which include commonly assigned U.S. Pat. No. 6,131,237 to Kasper et al., U.S. Pat. No. 7,784,148 to Lenkiewicz et al., and U.S. Pat. No. 7,320,149 to Huffman et al., which are incorporated herein by reference in their entirety. While the embodiments of the invention are described in the context of cleaning carpets, it will be understood that the embodiments of the invention are also suitable for use with any suitable soft surface, non-limiting examples of which include rugs, upholstery and drapes. 
         [0023]      FIG. 1  is a schematic of an extractor  10  suitable for use with the embodiments of the method. Any suitable type of extractor having a fluid delivery and recovery system can be used with the embodiments of the invention described herein. The details of the extractor are not germane to the invention; only those components necessary for a complete understanding of the embodiment of the invention are described. 
         [0024]    The extractor  10  includes a fluid delivery system comprising a first cleaning fluid supply  12  and a second cleaning fluid supply  14  storing first and second cleaning fluids, respectively. The first and second cleaning fluid supplies  12 ,  14  can include a refillable tank, container and/or bladder. The first and second cleaning fluids can comprise any suitable cleaning fluid, including, but not limited to, water, concentrated and/or diluted detergent, stain remover, odor remover and the like. For example, the first cleaning fluid can be water, and the second cleaning fluid can be a concentrated detergent. Although not illustrated, other supply tanks or containers can be provided such that the fluid delivery system delivers cleaning fluid from separate tanks or containers that contain the same or different concentrations or compositions of cleaning fluid. 
         [0025]    The first and second cleaning fluid supplies  12 ,  14  can be fluidly coupled with a mixing/metering assembly  16  through respective first and second cleaning fluid supply lines  18 ,  20 . The flow of fluid from the first and second cleaning fluid supplies  12 ,  14  through the first and second cleaning fluid supply lines  18 ,  20  to the mixing/metering assembly  16  can be controlled by first and second valve mechanisms  22 ,  24 , respectively. The first and second cleaning fluids can be optionally mixed by the mixing/metering assembly  16  to provide a cleaning solution to a spray assembly  26  for distributing the cleaning solution onto the surface to be cleaned. The spray assembly  26  can include one or more sprayers, such as those described in U.S. Pat. No. 7,784,148 to Lenkiewicz et al. referenced above. 
         [0026]    The fluid delivery system also includes an optional heater  28  and a pump assembly  30 . The heater  28  can be any suitable heater configured to heat fluids, such as an in-line heater. The pump assembly  30  has a first inlet in fluid communication with the mixing/metering assembly  16  and an outlet in fluid communication with an inlet of the spray assembly  26 . The pump assembly  30  is operatively connected to a motor/fan assembly  32  for operation of a primer stack portion thereof, as described in the aforementioned Kasper patent. Alternatively, the pump can comprise a conventional solenoid pump. 
         [0027]    The fluid recovery system comprises a recovery chamber or tank  34  which is used to store spent cleaning solution and debris that is recovered from the surface to be cleaned. A nozzle assembly  36  is in fluid communication with the recovery tank  34  for ingesting spent cleaning solution and debris for collection within the recovery tank  34 . The nozzle assembly  36  can be part of a foot assembly (not shown) configured to be positioned adjacent the surface to be cleaned during use of the extractor  10 . The foot assembly can further include additional components such as an agitator assembly comprising one or more agitators, such as a brush roll, for example, for agitating and providing mechanical cleaning action to the surface to be cleaned. The motor and fan assembly  32  is fluidly coupled with the nozzle assembly  36  for providing suction to draw the spent cleaning solution and debris on the surface being cleaned through the nozzle assembly  36  and into the recover chamber  34 . Air drawn into the fluid recovery system through the nozzle assembly  36  is drawn through the motor and fan assembly  32  before being exhausted from the extractor  10 . 
         [0028]    The extractor  10  can also include a control system  38  for operably controlling the various components of the extractor  10 , such as the first and second valve mechanisms  22 ,  24 , the mixing/metering assembly  16 , the pump  28 , the heater  30  and the motor/fan assembly  32 , for example. The extractor  10  can also include an actuator  40 , such as a button or trigger, which can be selectively actuated to control the delivery of cleaning solution to the surface to be cleaned. 
         [0029]    In use, upon actuation of the actuator  40  by a user, the control system  38  can control the first and second valve mechanisms  22 ,  24  to supply the first and second cleaning fluids to the mixing/metering assembly  16  to generate a cleaning solution. The control system  38  can further control the pump  28  and optionally the heater  30  to provide the cleaning solution to the spray assembly  26  for application to the surface to be cleaned. The control system  38  can be configured to control the motor/fan assembly  32  such that during application of the cleaning solution, suction is not applied through the nozzle assembly  36 . Alternatively, the control system  38  can be configured to apply suction during the application of the cleaning solution. Upon release of the actuator  40 , the control system  38  can control the components of the extractor  10  to cease dispensing of the cleaning solution through the spray assembly  26 . The spent cleaning solution and debris on the surface being cleaned can be removed by suction through the nozzle assembly  36  and stored in the recovery chamber  34  for later disposal by the user. Suction through the nozzle assembly  36  can be initiated automatically by the control system  38  upon release of the actuator  40 , manually by the user through a second actuator operably coupled with the motor/fan assembly  32 , or suction can be automatically applied by the control system  38 . 
         [0030]      FIG. 2  illustrates a method  100  of use of the extractor  10  for cleaning a surface to be cleaned, such as an area of carpet. The methods of the embodiments of the invention are described with respect to a “stroke” of the extractor  10 . As used herein, a stroke refers to movement of the extractor  10  relative to the surface being cleaned in a single direction, with or without the distribution of cleaning solution, from the perspective of a user positioned behind the extractor  10 . A “forward stroke” refers to movement of the extractor  10  in a forward direction, away from the user. A “reverse stroke” refers to movement of the extractor  10  in a reverse direction, back towards the user. A “wet stroke” refers to a stroke, either forward or reverse, during which the user has actuated the actuator  40  to distribute cleaning solution to the surface being cleaned. A “dry stroke” refers to a stroke, either forward or reverse, during which the motor/fan assembly  32  is actuated to provide suction to the nozzle assembly  36  to remove spent cleaning solution and/or debris on the surface being cleaned without distribution of cleaning solution to the surface. During the dry stroke, the agitator assembly can also be actuated. 
         [0031]    The method  100  starts with the assumption that the user has filled the first and second cleaning fluid supplies  12 ,  14  with the desired cleaning fluids, has positioned the extractor  10  on the surface to be cleaned and is standing behind the extractor  10 . At  102  the user can push the extractor  10  in a forward direction, away from the user, while actuating the actuator  40  to distribute cleaning solution to the surface, thus completing a first wet stroke. At  104  the user can pull the extractor  10  in a reverse direction, back towards the user, over the same general area traversed during the first wet stroke  102 , without actuating the actuator  40 , thus completing a first dry stroke. At  106  the user can again push the extractor  10  in a forward direction, generally traversing the same area of the surface traversed during the first wet stroke at  102  and the first dry stroke at  104 , while actuating the actuator  40  to distribute the cleaning solution, thus completing a second wet stroke. At  108  the user can pull the extractor  10  in a reverse direction, generally traversing the same area of the surface traversed during the previous strokes at  102 ,  104  and  106 , without actuating the actuator  40 , thus completing a second dry stroke. 
         [0032]    While the method  100  is described as beginning with a forward stroke, it will be understood that the method  100  can begin with a reverse stroke. The method  100  can be completed one or more times over the same general area of the surface or may be used to clean a larger area. For example, the method  100  can be used one or more times on the same general area to clean a stain or spot on the surface being cleaned. In another example, the method  100  can be repeated multiple times in the process of cleaning an entire room. 
         [0033]    The method  100  can be used to clean a carpet segment having a first edge defined by a position of the extractor  10  at the start of the first wet stroke, a second edge defined by a position of the extractor  10  at the end of the first wet stroke and opposite side edges extending between the first and second edges of the carpet segment. The width of the carpet segment between the opposite side edges can generally be defined by a width of a cleaning solution spray pattern that is dispensed by the spray assembly  26  and/or a width of the nozzle assembly  36 . Alternatively, the width of the carpet segment can be defined by the width of the extractor foot assembly, with the cleaning solution spray pattern and the width of the nozzle assembly  36  extending across at least a portion of the width of the foot assembly. In this manner, movement of the extractor  10  according to the strokes of the method  100  defines a relatively rectangular carpet segment that is cleaned according to the method  100 . 
         [0034]    Movement between edges of the carpet segment during the method  100  generally defines a stroke, with each stroke being carried out successively such that an end of one stroke is followed by a beginning of a second stroke within a relatively short period of time, on the order of seconds or minutes, for example. In one example, the period of time between strokes may be based on the amount of time it takes a user to actuate the actuator  40  to dispense a cleaning solution at the beginning of a wet stroke and provide momentum to move the extractor  10  and/or the amount of time it takes a user to release the actuator  40  at the end of a wet stroke and reverse the movement of the extractor  10 . 
         [0035]    A distance between the first and second edges of the carpet segment can vary depending on the user&#39;s approach to cleaning the surface to be cleaned. For example, when the user is cleaning an entire room, the distance between the first and second edges of the carpet segment may be greater than the distance between the first and second edges when the user is cleaning only a portion of a room, such as during a spot treatment. 
         [0036]      FIG. 3  illustrates a second method  200  of use of the extractor  10  for cleaning a carpet segment of a surface to be cleaned, such as an area of carpet. The method  200  is similar to the method  100  except for the sequence and ratio of wet and dry strokes. 
         [0037]    The method  200  starts with the assumption that the user has filled the first and second cleaning fluid supplies  12 ,  14  with the desired cleaning fluids, has positioned the extractor  10  on the surface to be cleaned and is standing behind the extractor  10 . At  202  the user can push the extractor  10  in a forward direction, away from the user, while actuating the actuator  40  to distribute cleaning solution to the surface, thus completing a first wet stroke. At  204  the user can pull the extractor  10  in a reverse direction, back towards the user, over the same general area traversed during the first wet stroke  202 , while actuating the actuator  40  to distribute cleaning solution to the surface, to complete a second wet stroke. At  206  the user can again push the extractor  10  in a forward direction, generally traversing the same area of the surface traversed during the first and second wet strokes at  202  and  204 , while actuating the actuator  40  to distribute the cleaning solution, to complete a third wet stroke. At  208  the user can pull the extractor  10  in a reverse direction, generally traversing the same area of the surface traversed during the previous strokes at  202 ,  204  and  206 , without actuating the actuator  40 , thus completing a first dry stroke. 
         [0038]    Similar to the first method  100 , the method  200  can be completed one or more times over the same general area of the surface or may be used to clean a larger area. For example, the method  200  can be used one or more times on the same general area to clean a stain or spot on the surface being cleaned. In another example, the method  200  can be repeated multiple times in the process of cleaning an entire room. 
         [0039]    The methods  100  and  200  provide different cleaning stroke sequences that can be used with an extractor to provide improved cleaning performance compared to the standard sequence of cleaning strokes used with an extractor, as illustrated by the test results provided below. 
         [0040]    Cleaning Performance Evaluation 
         [0041]    Methods 
         [0042]    ASTM International has proposed a test method for a laboratory test for determining the relative carpet cleaning effectiveness of a wet extraction cleaning system when tested under standard conditions titled “DRAFT Test Method for Measuring the Carpet Cleaning Effectiveness of Wet Extraction Cleaners,” dated Jan.  20 ,  2010 . The cleaning system is defined as a wet extraction appliance coupled with its included or recommended chemical cleaning formula. The proposed standard determines the carpet cleaning effectiveness based on a standard cleaning method that includes two wet strokes followed by two dry strokes (“two wet/two dry strokes”). 
         [0043]    The carpet cleaning effectiveness of three different commercially available extraction cleaning systems was tested according to the ASTM draft standard using the two wet/two dry strokes cleaning method outlined in the proposed standard. The cleaning effectiveness was also tested using the method  100  and  200  of  FIGS. 2 and 3  according to the ASTM draft standard in place of the two wet/two dry strokes standard cleaning method to compare the cleaning effectiveness of the methods  100  and  200  with the standard method. 
         [0044]    The amount of water retained (“water retention”) by the carpet after cleaning according to the ASTM draft standard using each of the different cleaning methods was determined by weighing the carpet test sample before and after cleaning 
         [0045]    Extraction Cleaning Systems 
         [0046]    The three extraction cleaning systems tested include: 
         [0047]    1) BISSELL® Lift-Off® Deep Cleaning System with the BISSELL® 2X Professional Deep Cleaning formula (“BISSELL® Lift-Off”). 
         [0048]    2) BISSELL® Proheat® 2X 9200 Deep Cleaning System with the BISSELL® 2X Professional Deep Cleaning formula (“BISSELL® Proheat®”). 
         [0049]    3) Hoover® Max Extract® 60 with the Hoover® 2X Concentrate Deep Cleansing formula (“Hoover® Max Extract®”). 
         [0050]    Test Results 
         [0051]      FIGS. 4-10  illustrate test data obtained for the three extraction systems listed above, BISSELL® Lift-Off®, BISSELL® Proheat®, and Hoover® Max Extract® according to the ASTM draft standard using each of the different cleaning methods, the ASTM standard cleaning method and the methods  100  and  200  of  FIGS. 2 and 3 . 
         [0052]    Charts  300 ,  302  and  304  of  FIGS. 4-6 , respectively, illustrate the average percent clean test results at the 95% confidence interval for each of the three extraction cleaning systems according to the ASTM draft standard using the two wet/two dry strokes standard cleaning method, the method  100  (“1 wet 1 dry/1 wet 1 dry”) and the method  200  (“3 wet/1 dry”). For all of the  FIGS. 4-9 , the horizontal striped bars correspond to the first, forward stroke traveling in the direction of the lay of the carpet test sample (with the lay of the carpet) and the white bars correspond to the first stroke traveling in the direction opposite to the lay of the carpet test sample (against the lay of the carpet). The average percent clean value and percent clean value plus and minus two standard deviations (“+2s” and “−2s”) is also shown. The percent clean values are calculated as described in the ASTM draft standard. 
         [0053]    Charts  306 ,  308 , and  310  of  FIGS. 7-9 , respectively, illustrate the average Delta-E (ΔE) at the 95% confidence interval for each of the three extraction cleaning systems according to the ASTM draft standard using the two wet/two dry strokes standard cleaning method, the method  100  (“1 wet 1 dry/1 wet 1 dry”) and the method 200 (“3 wet/1 dry”). As discussed in the ASTM draft standard, ΔE is a number representing the distance in color space between two colors. ΔE is derived mathematically and is used in colorimetry to evaluate the extent of color differences and change. ΔE (s-e) is a measure of the change in ΔE between the soiled carpet sample and the carpet sample after it has been cleaned. 
         [0054]    As can be seen in  FIGS. 4-9 , the sequencing of the wet and dry strokes used during an extraction cleaning method effects the carpet cleaning effectiveness of the BISSELL® Lift-Off®, BISSELL® Proheat®, and Hoover® Max Extract® extraction cleaning systems. Referring now to  FIGS. 4-6 , in general, the average percent clean for 1 wet 1 dry/1 wet 1 dry (method  100 ) and 3 wet/1 dry (method  200 ) cleaning methods is greater than the standard 2 wet/2 dry cleaning method for all three extraction cleaning systems when starting cleaning with the lay of the carpet. As illustrated in  FIGS. 7-9 , in general, ΔE(s-e) is greater for the 1 wet 1 dry/1 wet 1 dry (method  100 ) and 3 wet/1 dry (method  200 ) cleaning methods than the standard 2 wet/2 dry cleaning method for all three extraction cleaning systems both with and against the lay of the carpet. This data suggests that the 1 wet 1 dry/1 wet 1 dry (method  100 ) and 3 wet/1 dry (method  200 ) cleaning methods are on par and often better than the standard 2 wet/2 dry cleaning method for cleaning carpets. 
         [0055]    Chart  312  of  FIG. 10  illustrates the average amount of liquid retained by the carpet when cleaned using each three extraction cleaning system for each cleaning method with and against the lay of the carpet. 
         [0056]    As can be seen in  FIG. 10 , while each of the three cleaning methods includes four strokes, each method results in different amounts of liquid retained by the carpet. For example, while the standard 2 wet/2 dry method and method  100  of 1 wet 1 dry/1 wet 1 dry both comprise two wet strokes and 2 dry strokes, the sequencing effects the amount of liquid retained by the carpet, with the method  100  resulting in an increase in the amount of retained liquid compared to the standard method. The method  200  of 3 wet/1 dry has four strokes total, the same as the standard method and method  100 , however the method  200  has 3 wet strokes and 1 dry, resulting in more liquid retained by the carpet than either the standard method or method  100 . 
         [0057]    Charts  314  and  316  of  FIGS. 11 and 12 , respectively, illustrate the test data obtained for the BISSELL® Lift-Off® extractor used with the BISSELL® 2X Professional Deep Cleaning formula and the BISSELL® 2X Fiber Cleansing formula according to the ASTM draft standard using each of the different cleaning methods, the ASTM standard cleaning method and the methods  100  and  200  of  FIGS. 2 and 3 . 
         [0058]    As can be seen in  FIGS. 11 and 12 , even when different cleaning formulas are used with the extractor, the sequencing and ratio of wet and dry strokes in the cleaning method affects the cleaning effectiveness of the extraction cleaning system. 
         [0059]    The results shown herein illustrate the effect of the sequencing and the ratio of wet and dry strokes in the cleaning effectiveness of an extraction cleaning system. Even when the total number of strokes in the cleaning method is the same, the cleaning effectiveness and the amount of liquid retained by the carpet varies depending on the sequencing and the number of wet and dry strokes. This information can be provided to a user in the form of an instructional manual or a label on the machine such that the user can make an informed decision on how to use the extraction cleaning system to clean the carpet to meet the needs of the user. 
         [0060]    For example, if the user only desires a normal level of cleaning effectiveness and low liquid retention, the standard 2 wet/2 dry method can be used. Alternatively, if the user desires a higher level of cleaning effectiveness and a slightly greater amount of liquid retention is acceptable, then the user can use the method  100  of 1 wet 1 dry/1 wet 1 dry. In a third option, if the user desires a higher level of cleaning effectiveness and is not concerned with the amount of retained liquid, the user can use the method  200  of 3 wet/1 dry. The user can use additional dry strokes as needed following the method  200  or any of the methods described herein to suction additional liquid from the surface to decrease the amount of liquid retained by the surface. 
         [0061]    To the extent not already described, the different features and structures of the various embodiments may be used in combination with each other as desired. That one feature may not be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. 
         [0062]    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 disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims.