Abstract:
A method of maintaining a floor using a cleaning device is provided. The cleaning device includes a cleaning solution fluid dispensed adjacent to the cleaning device. The cleaning solution is comprised of at least two components, a bulk diluting fluid like water and one or more cleaning chemicals which are dispensed from separate reservoirs carried by a maintenance machine. The cleaning chemical is pumped to mix it with the bulk fluid in a controlled ratio. Operation of the pump and a discharge flow control device are controlled by a controller system which permits dispensing of a mixed cleaning solution of combined cleaning chemical(s) and bulk fluid at a desired ratio and at a desired flow rate of dispensing of cleaning solution components.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This Application is a Divisional Application of application Ser. No. 11/307,703 filed Feb. 17, 2006, currently pending, of the same title, the entire disclosure of which is incorporated herein by reference. This application claims the benefit of and priority to U.S. patent application Ser. No. 11/307,703. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Floor maintenance machines are well known in the industry and are used for cleaning floors as by scrubbing. Examples of such machines are available from Clarke and Nilfisk-Advance. The maintenance machines generally include a tank for a cleaning solution, a cleaning device which may be an orbitally moving or rotating brush or scrubbing pad mounted on an assembly for moving the machine about a floor. The brush or pad may move about a vertical or horizontal axis. A power drive device may be provided to propel the maintenance machine while cleaning fluid solution is dispensed onto the floor adjacent the cleaning device. The cleaning solution may be removed from the floor with a recovery system that can include a squeegee and vacuum that will move recovered cleaning solution to a storage tank for later disposal. Such machines can either be a walk behind or riding type machine and can clean a path typically about 15 inches to about 48 inches wide. The walk behind machines may be a push type or a driven type as is well known in the art. 
         [0003]    One of the issues with such machines is the uniform dispensing of cleaning fluid onto the floor. This can be both by the rate of dispensing and by the ratio of cleaning chemicals to water. The cleaning solution formed by the combination water (a typical bulk diluting fluid) and cleaning chemicals and can be either a liquid and/or foam. One early solution to the ratio of water to cleaning chemicals, was the use of a pre-mix. However, this was expensive since water had to be shipped while water was locally available and it did not allow for easy customization of the cleaning fluid for a particular job. One solution to this latter problem is mixing the water of the cleaning solution with the chemicals of the cleaning solution on site. However, this can be problematic because of the skill level of the machine operators plus, once mixed, the ratios may not be changed easily when in the storage tanks on the maintenance machine to change cleaning solutions though requires emptying of the storage tank. Another solution to the problem is to mix the water and chemicals together on the cleaning machine by introducing the chemicals into the water prior to dispensing to the floor to be cleaned. 
         [0004]    There is thus a need, for an improved floor maintenance machine that will allow mixing of the cleaning bulk liquid and concentrated chemicals on the maintenance machine during operation thereof to provide accurate control of the final ratio of water to added cleaning chemicals and the rate of dispensing to the floor. 
       SUMMARY OF INVENTION 
       [0005]    The present invention involves the provision of both a method and apparatus that will effect mixing of one or more cleaning chemicals with a diluting fluid on a floor maintenance machine during machine operation. 
         [0006]    The present invention involves the provision of a floor maintenance machine that utilizes separate sources of a bulk diluting fluid like water and one or more cleaning enhancement chemicals and provides a mixing system for effecting a controlled ratio mixture of fluid and cleaning chemical to form a cleaning solution and allows for the adjustment of the ratio of cleaning chemical to fluid by a machine operator. The system also permits for the adjustment of the amount of cleaning solution dispensed to the floor in a given amount of time. The maintenance machine includes a cleaning device, for example, a scrubber, at least two storage reservoirs connected in flow communication by respective outlet conduit portions of a conduit system. A pump is provided for pumping the cleaning chemical into the conduit system on a predetermined controlled basis as controlled by a controller. A discharge flow control device is provided for controlling the amount of cleaning solution dispensed to the floor adjacent the cleaning device. The operation of the flow control device is also controlled by a controller. A level sensor can be provided for monitoring the level (pressure head) of diluting fluid in its storage tank. Signals from the level sensor and the flow control device may be used to control operation of the pump and/or the flow control device. The signal from the level sensor can be used to control operation of the flow control device to provide a uniform flow at all head pressures. 
         [0007]    The present invention also involves the provision of a method of maintaining a floor using a cleaning device having a cleaning solution fluid dispensed adjacent to the cleaning device. The cleaning solution is comprised of at least two components, a bulk diluting fluid like water and one or more cleaning chemicals which are dispensed from separate reservoirs carried by a maintenance machine. The cleaning chemical is pumped to mix it with the bulk fluid in a controlled ratio. Operation of the pump and a discharge flow control device are controlled by a controller system which permits dispensing of a mixed cleaning solution of combined cleaning chemical(s) and bulk fluid at a desired ratio and at a desired flow rate of dispensing of cleaning solution components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0008]      FIG. 1  is a schematic illustration of a system for mixing and dispensing cleaning fluid to a cleaning device for cleaning floors. 
           [0009]      FIG. 2  is a perspective view of a floor maintenance machine. 
       
    
    
       [0010]    Like numbers throughout the various Figures designate like or similar parts or construction. 
       DETAILED DESCRIPTION  
       [0011]    The referenced numeral  1  designates generally a floor maintenance machine. The machine  1  may be driven by a power source (not shown) and typically rides on three or more wheels  5  at least one of which may be driven by the power source. The machine  1  may also be manually propelled. The wheels  5  are positioned at appropriate locations on the lower-most portion of the machine  1  and preferably at least one of the wheels  5  is steerable to help direct the motion of the machine  1 . Such machines are well known in the industry and may be typified by the Focus and Boost models as provided by Clarke of Springdale, Ark. Such machines may be a walk behind machine or a machine that can be ridden by an operator. In a preferred embodiment, the machine  1  is constructed to clean what are referred to as soft, textured, smooth or hard floors for example carpet, linoleum, concrete, tile, wood and vinyl floors. In such an apparatus, the machine  1  can also include a recovery system having one or more squeegees  6 , a storage tank or reservoir  3  and a vacuum pick up system to help remove used cleaning solution from the floor and temporarily store it for later discharge. The machine  1  will also include a cleaning device  7  used to contact the floor to scrub the floor. The cleaning device  7  can include one or more scrubbers  8  such as bristle brushes or a fibrous pads or the like depending on the type of floor to be cleaned, the cleaning solution used as well as the amount of and type of dirt on the floor. A scrubber  8  may move about a generally vertical or horizontal axis. The machine  1  includes a cleaning fluid dispenser  9  positioned adjacent to the cleaning device  7  to discharge cleaning fluid onto the floor and/or a scrubber  8  to help in the cleaning process. The dispenser  9  can include one or more discharge nozzles or outlets and may include a dispensing manifold as is known in the art. The machine  1  will carry the various components illustrated in  FIG. 1  and in a particularly preferred embodiment the three reservoirs  3 ,  11  and  12 . The reservoir  11  is for a first cleaning solution component which is preferably a bulk diluting fluid, for example, water. The reservoir,  12 , is for the storage of another component of a cleaning solution for example, cleaning chemicals such as soaps, detergents, enzymes, surfactants and blends thereof. Because the cleaning chemicals are preferably concentrated and are to be diluted, the reservoir  12  can be significantly smaller than the reservoir  11 . The reservoirs  11 ,  12  can be contained in a single unit, however, separate reservoirs are preferred. It is preferred that the reservoirs  11  and  12  be made of a polymeric material so as to be resistant to chemical degradation by the stored components, leak resistant and be relatively break resistant. Polyethylene and polypropylene are generally suitable polymeric materials. 
         [0012]    In a preferred embodiment, a level sensor  14  is associated with the reservoir  11  and is operable to provide a signal indicative of the level (pressure head) of cleaning fluid contained within the reservoir  11 . The signal can be used to regulate the open time of a flow control device  18  within a given time period so that even flow rate can be achieved from the reservoir  11 . The level sensor  14  can be a pressure type sensor or any other suitable level sensor and can be mounted on the tank or can have a sensing element mounted on or integrated on the controller  16 . A suitable sensor  14  is a 30 inch G-4V-mini from All Sensors. 
         [0013]    The level sensor  14  is in turn connected to a controller  16  and/or  31  that is operable to receive a signal indicative of the level of fluid within the reservoir  11  and a signal from the flow control device  18  indicating its operation. The controller  16  may be any suitable controller such as a programmable logic controller (microprocessor) and may contain various look up tables to effect its operation and outputs in accordance with pre-programmed instructions. A suitable controller  16  is a Custom Control from Courtney Electronics. The controller  16  provides at least one output signal operable to control a pump  20  as discussed below. An adjustment device  22  such as a potentiometer is connected to or integrated with portions of the controller  16  and is operable to control the ratio of cleaning chemicals from the reservoir  12  to the cleaning fluid dispensed from the reservoir  11 . The reservoir  12  is connected in fluid flow communication to the pump  20  via a conduit portion  23  of a conduit system designated generally  21 . In turn, the pump  20  is connected in fluid flow communication with the conduit portion  26  and T-joint  29  via a conduit portion  24  of the system  21 . The flow control device  18  is in turn connected in fluid flow communication to the conduit portion  24  via a conduit portion  26  as for example at a T-joint  29 . The conduit portions  24 ,  26 ,  28  and check valve  35  may be an integral unit. The conduit portions  26 ,  38 , the flow control device  18  and T  29  all may help effect mixing of the fluids from the reservoirs  11 ,  12 . Mixing can also occur after the fluids are dispensed from the dispenser  9 . It is to be noted that the fluids from the reservoirs  11 ,  12  can be dispensed in separate streams to the brush  8  and let the brush  8  effect mixing. 
         [0014]    The flow control device  18  is operable to control the flow of combined fluids from the reservoirs  11 ,  12  to the dispenser  9 . In a preferred embodiment, the flow control device  18  is a valve such as an on (open)/off (closed) valve but it is to be understood that a proportioning valve could also be used and amount of openness would be monitored. The device  18  can also be a pump, preferably a positive displacement pump like a piston pump or a peristaltic pump, a venturi pump or injection pump could also be used. The pump can function as a valve or include a valve. The operation of the flow control device  18  is effected by a controller  31  operably connected to the flow control device  18 . In one embodiment, the controller  31  is operable to control the amount of time the valve (when the device  18  is an on/off valve) is in the open position and hence controls the amount of time that the valve is in the closed position. A suitable device  18  is a Deltrol DSVP10 solenoid valve. A signal is provided to the controller  16  via conductor  33  indicating the operation of the device  18  to the controller  16 . The controller  31  may be provided with changeable time functions, as for example, by modules that may be substituted in the controller  31 . A suitable controller  31  is a Custom Control from Courtney Electronics. The time functions may be selected and changed to control the cycle time of the device  18  in the case the device  18  is an on/off valve and change the degree of open if the device  18  is a proportioning valve. The controller  31  is operable to open and close an on/off valve at preset intervals, for example one second, five second and ten second cycle time intervals with a certain portion of the time interval having the valve open and the remainder of the portion of the cycle time, the valve is closed. The open time of the flow control device  18  can be regulated according to the signal received from the sensor  14 . The open time of the device  18  would increase over a cycle or a longer time period as the fluid level in the reservoir  11  and the head pressure decrease. A signal indicating the operating condition of the device  18 , for example, the time the device is open is transmitted to the controller  16  so the controller  16  can control operation of the pump  20  in accordance with programmed instructions. The pump  20  will preferably only be on (pumping) when the device  18  is open to help reduce pressure build up in the conduits  24 ,  26  and the pump  20 . A check valve  35  may be provided in the conduit  24  between the pump  20  and the T  29  to prevent fluid from the reservoir  11  or in the conduit  24  or  26  from flowing back into the pump  20  and possibly the reservoir  12 . The check valve  35  is preferably a low pressure valve, i.e., requires low pressure to open the valve from its closed position for example a 1 psi pressure differential across the check valve has been found acceptable for a breaking pressure. An acceptable valve  35  is a 426 Series 1 psi check valve from Specialty Mfg. 
         [0015]    Fluid flows from the open device  18  through a conduit  38  to a dispenser  9  such as one or more nozzles adjacent the cleaning device  7  for dispensing of cleaning solution which is a combination of fluid from the reservoir  12  and fluid from the reservoir  11 . Any one or all of the fluids may be a foam if desired but are preferably liquid at least until reaching dispenser  9 . 
         [0016]    The pump  20  is preferably of a metering type and more preferably of the positive displacement type for example a piston pump. The pump  20  could also be a venturi or injection type pump. The pump  20  is controlled in its operation by the controller  16  in response to input signals from the adjustment device  22 , valve operation signal from the flow control device  18  and pre-programmed instructions. It is to be noted here, that the controller  31  and controller  16  may be integrated into a single unit if desired. The pump  20  is connected to the controller  16  via a conductor  40  wherein controlled electrical currents are transmitted from the controller  16  to the pump  20 . The pump  20  includes both a pump device like a piston/cylinder and a power drive component like an electric motor or linear drive such as a solenoid. 
         [0017]    In operation, the level sensor  14  is operable to provide signals to help maintain an appropriate ratio of cleaning fluid from the reservoir  12  to the diluting fluid like water which is gravity fed from the reservoir  11  for dispensing to the flow control device  18 . The level sensor  14  is connected to the controller  16  as by conductor  42  and through the controller  16 , controls the operation of the pump  20  preferably by controlling the pump in a frequency modulated operating format. In a preferred embodiment, the pump  20  will provide a metered amount during each on cycle for example one stroke of a piston in a cylinder, which may, for example, take 16 milliseconds to achieve. Then the pump  20  will be deactivated and be in an off mode until reenergized for another pump cycle. In a larger time frame perspective, the controller  16  is operable to control the number of strokes per unit of time for example strokes per minute that the pump  20  is providing fluid from the reservoir  12  to the conduit portion  24 . An acceptable pump  20  is an EMS  10  piston pump from Clark Solutions. The adjustment device  22  may be adjusted from a preset setting to control the ratio of cleaning fluid in the reservoir  12  to water in the reservoir  11  by controlling the frequency of pulses of electrical current output, e.g., 1 HZ, 2 HZ, from the controller  16  to the pump  20 . Thus, in a preferred embodiment the controller  16  controls the time between on cycles for the pump  20  with the duration of the energization of the pump being held at a fixed time, preferably, one discharge stroke of a piston in a cylinder. Operation signals from the controller  16  may be established by look up tables programmed in the controller  16 . The output flow control device  18  is preferably an on/off valve and is controlled for its on time by the controller  31  which also controls the time that the valve  18  is closed. The valve operation may be changed by changing settings in the controller  31  as with an adjustment device  40  like a potentionmeter. The controller  16  receives a signal indicative of the operation of the device  18  via conductor  33  which signal can be from the device  18  or the controller  31  preferably indicating when the device  18  is open for flow. The controller  16  then energizes the pump  20  to pump at the frequency determined by the look up table in the controller  16  according to the setting of the adjuster  22 . The construction of the invention avoids a problem of ratio control when the pump is operating at low frequency if the device  18  were only open for a short period of time by looking at operation over a long period of time relative to short operating times of the device  18  and pump  20 . The controller  16  looks at the operation of the device  18  for its openness over time to operate the pump  20  at the appropriate frequency to provide the desired ratio of cleaner to diluting fluid. In an alternate embodiment, the level sensor  14  may provide a signal to the controller  31  via a conductor  41  to adjust operation of the flow controller  18  for the level of liquid in the reservoir  11 , i.e., the higher the level of liquid, the shorter the time the valve  18  need be open to thereby achieve a more constant flow output to the dispenser  9 . 
         [0018]    Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.