Abstract:
The present invention relates generally to an environmentally sensitive mobile cleaning system, and more specifically relates to a closed loop water recirculation system for high or ultra-high pressure mobile cleaning apparatus. The system includes a water tank sized to contain an established volume of fluid sufficient to circulate through the system, a pump to pressure the fluid to a cleaning head, a vacuum system to return the contaminated fluid to the system, and a filter means to remove the contaminants from the fluid so that clean fluid can be reintroduced to the cleaning head. The method comprises the steps of increasing the pressure of a fixed volume of fluid in a closed-loop system, jetting or blasting the surface with the pressurized fluid, vacuuming the blasted fluid into the system, and removing the contaminants from the fluid.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation in part and claims the priority of U.S. Patent Application No. 61/147,158, entitled “Mobile Water Recirculation System For Surface Cleaning Apparatus”, filed Jan. 26, 2009, the contents of which are incorporated herein in their entirety. This application is related to U.S. Pat. No. 7,255,116, entitled “Stripe Removal System”, issued Aug. 14, 2007, U.S. patent application Ser. No. 11/340,738, entitled, “Transportable Holding Tank For Stripe Removal System”, filed Jan. 26, 2006, and U.S. patent application Ser. No. 11/340,104, entitled “Mobile Mark Removal System”, filed Jan. 26, 2006, the contents of which are incorporated herein by reference. 
    
    
     FIELD OF INVENTION 
     The present invention generally relates to water treatment systems, and more particularly to a closed loop water treatment system that is particularly suited for surface cleaning apparatus. 
     BACKGROUND INFORMATION 
     Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment processes is to remove existing contaminants in the water, or reduce the concentration of such contaminants so the water becomes fit for its desired end-use. One such use can be returning water that has been used back into the natural environment without adverse ecological impact. 
     The processes that have been suggested for use in treating water for solids separation include physical processes such as settling and filtration, and chemical processes such as disinfection and coagulation. 
     Biological processes have also been employed in the treatment of water, and these processes may include, for example, aerated lagoons, activated sludge or slow sand filters. 
     Surface cleaning apparatus such as pressure washers are useful for cleaning a variety of objects. Such devices require a clean supply of water for proper operation, but create wastewater by entraining solids from the cleaned surface into the used source water. Although there are many types of pressure washing systems, a typical system utilizes an engine that powers a pump. The inlet side of the pump is connected to a low pressure water source such as a tank or a municipal water supply, while the high pressure side of the pump is connected to a high pressure hose and wand for controlling the flow of high pressure water generated by the pump. The high pressure water is directed at a surface to dislodge dirt, paint and the like, and the water is generally allowed to drain into the storm sewer. 
     Ultra-high pressure washers, supplying more than 25,000 P.S.I. are also known. These systems include a large engine, typically diesel, which operates a large multi-cylinder pump to generate high volumes of water at ultra-high pressures. The ultra-high pressure water is directed through piping and/or hoses to various types of blast heads suitable for controlling the flow and direction of the ultra-high pressure water. One particular use for ultra-high pressure water devices is the removal of stripes or other markings from road surfaces. When polymers such as paint or plastic are used for roadway marking, the surface of the pavement is penetrated from ⅛-⅜ inch; whereby water blasting is the only known method of removing the stripe material from below the surface without removing a portion of the roadway surface. Ultra-high pressure water washers are also utilized for removing paint from ships, cleaning industrial facilities, removing graffiti, removing rubber from aircraft runways and demolition. 
     One problem associated with both low and ultra-high pressure water cleaning equipment is maintaining an adequate supply of clean water for continuous operation of the system. Dirty or contaminated water causes numerous problems with water cleaning equipment such as excessive pump wear, clogged filters, nozzles, screens and the like. Because cleaning often needs to take place away from municipal water supplies, water is often transported to the cleaning site. Because the water cleaning equipment requires large volumes of water to be effective, additional equipment is needed to haul in tanks of water. Alternatively, cleaning must be stopped so that additional water may be obtained. 
     Recovery and disposal of the water is another problem facing water cleaning equipment users. Demolition or even the mere cleaning of surfaces results in the water becoming contaminated with dirt and debris. This problem is particularly exacerbated with ultra high pressure water cleaning equipment which breaks dirt and debris up into particles small enough to remain suspended within the water indefinitely. Therefore, the contaminated water should be properly recovered and thereafter cleaned or contained before it can be disposed of. 
     Industrial systems that utilize filter belts are also known to be used for solid/liquid separation processes, particularly the dewatering of sludges in the chemical industry, mining and water treatment. The process of filtration is primarily obtained by passing a pair of filtering cloths and belts through a system of rollers. The feed sludge to be dewatered is introduced from a hopper between two filter cloths (supported by perforated belts) which pass through a convoluted arrangement of rollers. As the belts are fed through the rollers, water is squeezed out of the sludge. When the belts pass through the final pair of rollers in the process, the filter cloths are separated and the filter cake is scraped off into a suitable container. Water sprays are typically utilized to clean the filter cloth before it is reused. The water spray is reclaimed to be reprocessed or diverted to a drain for disposal. However, in these systems it is typically the solid filter cake that the user is interested in recovering and not the water that was carrying the solid particles, and thus the water typically remains dirty and is discarded to the drain. 
     Therefore, there is a need in the art for a water recirculation system that is suitable for applications such as high pressure or ultra-high pressure water cleaning equipment. The water recirculation system should provide a predetermined amount of clean water to start the cleaning operation. The water recirculation system should recover the dirty and contaminated water expelled during the cleaning process for removal of dirt and debris so that the water can be recirculated through the pressure cleaning equipment. The water recirculation system should be efficient enough to recirculate a sufficient volume of water for continuous operation of the water cleaning system. The water recirculation system should retain the dirt and debris for proper disposal. The water recirculation system should be compact enough to fit on a mobile frame that may also contain the high or ultra-high pressure water cleaning equipment. 
     There is also a need in the art for a water filtration system that is suitable for municipal, industrial and private uses. The water filtration system should utilize a continuous filter belt in combination with a settling tank for water containing a coagulant. The filter belt should be submerged within the settling tank a predetermined distance to control the hydrostatic head pressure utilized to push the debris containing water through the filter belt to limit the adhesion of the particles to the filter belt so that vacuum can be utilized to clean the filter belt for continuous use. The filter belt should be sized and the head pressure selected to provide a desired volume of cleaned water. The water can then be used as is or supplied to additional equipment or processes for further cleaning. 
     Thus, the present invention provides a water recirculation system for stationary or mobile applications and is particularly suited for surface cleaning apparatus and the like which overcomes the disadvantages of the prior art systems. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to an environmentally sensitive mobile cleaning system, and more specifically relates to a closed loop water recirculation system for high or ultra-high pressure mobile cleaning apparatus. The water recirculation system works in combination with a mobile pressure cleaning apparatus for cleaning surfaces while minimizing water usage and containing contaminants before they enter a storm water drain system. The system includes a water tank sized to contain an established volume of fluid sufficient to circulate through the system, a pump to pressure the fluid to a cleaning head, a vacuum system to return the contaminated fluid to the system, and a filter means to remove the contaminants from the fluid so that clean fluid can be reintroduced to the cleaning head. The method comprises the steps of increasing the pressure of a fixed volume of fluid in a closed-loop system, jetting or blasting the surface with the pressurized fluid, vacuuming the blasted fluid into the system, and removing the contaminants from the fluid. 
     Accordingly, it is an objective of the present invention to provide an environmentally sensitive cleaning system. 
     It is a further objective of the present invention to provide a mobile water recirculation system for surface cleaning apparatus. 
     It is yet a further objective of the present invention to provide a mobile water recirculation system for surface cleaning apparatus that reduces particulate size within the recirculated water to less than 1 micron. 
     It is another objective of the instant invention to provide a novel sediment tank arrangement. 
     It is yet another objective of the instant invention to provide a mobile water recirculation system for surface cleaning apparatus that includes a coagulant injection system. 
     It is still yet another objective of the instant invention to provide a mobile water recirculation system for surface cleaning apparatus that includes a continuous belt type filter. 
     It is yet a further objective of the instant invention to provide a method of continuously cleaning water to remove suspended solids therefrom. 
     Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a block diagram that illustrates one embodiment of the mobile water recirculation system for surface cleaning apparatus of the instant invention; 
         FIG. 2A  is a top perspective view illustrating one embodiment of the vacuum tank illustrated in  FIG. 1 ; 
         FIG. 2B  is a top perspective view illustrating one embodiment of the vacuum tank illustrated in  FIG. 1 ; 
         FIG. 3  is a top perspective view of one embodiment of the sediment tank illustrated in  FIG. 1 ; 
         FIG. 4  is a top perspective view of one embodiment of the continuous belt filter; 
         FIG. 5  shows the mobile water recirculation system mounted on a mobile truck frame; 
         FIG. 6  is a section view of the sediment tank illustrating separation of the solids suspended within the water. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     Referring generally to  FIGS. 1 and 5 , a mobile water recirculation system  10  for surface cleaning apparatus is illustrated. The preferred embodiment of the water recirculation system generally includes a water supply tank  12 , a vacuum tank  14 , a sediment tank  16 , a coagulant tank  18 , a muck tank  20 , an ultra-high pressure pump  22 , and a blast head  34 . Clean water is stored in the water tank  12 . Preferably, the water tank  12  has about a 2,700 gallon capacity. The water tank  12  functions not only to store substantially non-contaminated water, but also to provide a constant source of water to the ultra-high pressure water pump  22 . Water drains from the water tank through water port  40 , entering supply line  30  which extends to charge pump  24 . Charge pump  24  forces the water through a mixing tube  26  so that coagulant from the injection pump  28  is thoroughly mixed with the water. The injection pump injects coagulant and/or flocculent into supply line  30  based on the measured amount of coagulant in the water as measured by the coagulant tester  32 . It should be noted that the coagulant may be injected into the system as the water enters the water tank  12  or vacuum tank without departing from the scope of the invention. Fluid exiting the mixing tube is routed through a 5 micron filter  36  and thereafter through a 1 micron filter  38 . The and 5 micron filters are preferably cartridge type filters that allow for easy maintenance. Water exiting the 1 micron filter is routed to the ultra-high pressure pump  22 . The ultra-high pressure pump preferably pumps about 12 gallons of fluid per minute at a pressure of about 40,000 pounds per square inch (PSI). Fluid discharges from the ultra-high pressure pump via high pressure line  46  to the blast head  34  which includes a plurality of nozzles  42 . From the nozzles  42 , the fluid impinges upon a surface entraining particles within the fluid. It should be noted that while the water recirculation system is particularly suited for use with pressure cleaning systems, it could be utilized with many municipal, industrial, and private water cleaning operations without departing from the scope of the invention. Vacuum pump  44  provides a negative pressure to vacuum tank  14  via line  45 . Vacuum line  48  extends between vacuum tank  14  and shroud  41  that extends around blast head  34 . The shroud contains the water as it impinges upon the surface so that the vacuum can draw the solid containing dirty water into the vacuum tank  14 . 
     Referring to  FIGS. 1 ,  2 A and  2 B, the vacuum tank is illustrated. The vacuum tank  14  includes an outer wall having sufficient thickness to withstand the vacuum created by vacuum pump  44  which is preferably a roots blower type. Contained within the vacuum tank is a basket constructed from an expanded metal and supported to be spaced away from the outer wall  52  on all sides. A filter bag  56  is hung from the outer wall  52  on hooks  58  so that the top of the bag is open to accept the dirty water flowing into the vacuum tank through vacuum line  48 . The dirty water flows through the filter bag  56  to the area between the basket  54  and the outer wall  52 , leaving a large portion of the entrained solids within the filter bag  56 . As the vacuum tank  14  fills with water, transfer pump  60  moves water from the vacuum tank to the sediment tank  16  via transfer line  62 . Transfer line  62  includes a float assembly  64  at about a distal end thereof. The float assembly maintains the aperture  66  below the upper surface of the dirty water and above the bottom of the tank as it has been found that a layer of debris floats on the upper surface of the water while the larger solids settle to the bottom of the vacuum tank.  FIG. 2B  illustrates an alternative embodiment of the vacuum tank illustrated in  FIG. 2A . In this embodiment, the vacuum tank  14  includes at least one magnet  55  secured to one of the tank walls. In a most preferred embodiment, the magnet  55  is an electro-magnet, secured to the tank so that the magnetic flux created by the magnet contacts the water flowing into the vacuum tank  14 . In this manner, magnetic particles or particles including a magnetic coagulant and/or flocculent are attracted to the magnet thereby removing them from the water. Turning off or scraping the magnet allows these particles to be removed from the tank when the vacuum tank is emptied. 
     Referring to  FIGS. 1 ,  3 ,  4  and  5 , the sediment tank  16  is illustrated. The sediment tank includes an outer shell  66 . Within the outer shell  66  are one or more, and preferably a pair of horizontal baffles  68 . The horizontal baffles include a plurality of apertures sized to cooperate with a vertical baffle system illustrated herein as sediment tubes  69 . The sediment tubes  69  are preferably about 2 inches in diameter, and in a most preferred embodiment there are about 200 sediment tubes suspended between the horizontal baffles  68  within the sediment tank  16 . The sediment tubes  69  are sized to utilize vibrations from the mobile frame to cause the liquid contained therein to agitate suitably to allow the coagulant to function and bind the suspended solids  67  within the fluid  71  so that they drop to the bottom of the sediment tank faster than the water level rises through the tank. Tubes that are too small don&#39;t allow adequate agitation, while tubes that are too large provide too much agitation and prevent settling of the suspended solids. It should be noted that other vertically oriented baffles sized and shaped to utilize vibration to bind suspended solids within a liquid may be utilized without departing from the scope of the invention. It should also be noted that other means of applying free or forced vibration to the sediment tank may be utilized without departing from the scope of the invention. Such vibrations may be random or periodic and may be generated by one or more devices well known on the art. The outer shell  66  and the transfer pump  60  are preferably sized so that the water rises within the tank at about 2 inches per minute. It has been found through experimentation that a coagulant such as aluminum chlorhydrate will bind the suspended solids  77  together and they will fall through the tubes at about 4 inches per minute. In this manner, the fluid, e.g. water, retains less solids as it moves vertically through the sediment tank. Pivotally mounted within the lid  70  of the sediment tank  16  is a continuous filter  72  ( FIG. 4 ). The continuous filter includes a belt  74  of filter material such as, but not limited to, cloth, a pair of rollers  76 , a divider plate  78  and a vacuum head  80 . The belt  74  is sized to extend around the rollers  76 . At least one of the rollers includes a roller motor  82  sized to rotate the roller at about 6 inches per minute. Rollers having internal motors are well known in the art of conveyors and may include frequency generators or stepper motors to control the rotational speed of the roller. Fluid flowing upward through the sediment tank flows through the bottom portion of the filter belt depositing any remaining solids  77  on the surface thereof. The cleaned water is allowed to flow to the fresh water tank  12  for reuse. The divider plate  78  separates the lower (first) and upper (second) portions of the belt so that the upper portion of the belt is subjected to vacuum through the vacuum head to clean the upper portion of the filter belt. The vacuum head is preferably sized to cover the width of the belt. The filter belt is sized and positioned into the water column  71  so as to regulate the head pressure provided by the fluid flowing upward through the sediment tank. In a most preferred embodiment, the filter belt is a 1 micron cloth belt submerged about six inches into the water. This construction allows the user to precisely establish the pressure, per square unit of measure that is applied to the filter belt to force the liquid through the filter. In this manner, lowering the filter raises the head pressure and raising the filter toward the surface of the water lowers the head pressure. At a flow rate of about 12 gallons per minute, about 4,600 square inches of 1 micron filter belt have been found to be sufficient, so that about 5 inches of mercury vacuum are sufficient to clean the filter belt. The filter belt is sized to allow the desirable amount of water to flow therethrough at a head pressure that allows the solid particles  77  to be lifted from the filter belt  74  with vacuum after use. Altering the size of the mesh of the filter belt  74  may require repositioning of the filter belt in the column of water  71  to maintain the desired characteristics. The fluid then exits the sediment tank  16  through aperture  84  and flows through conduit  86  to the water supply tank  12 . As the dirty filter belt travels around the rollers, the vacuum head  80  uses vacuum from the vacuum tank  14 , supplied via conduit  88 , to remove the solid debris from the surface of the filter belt. A muck tank  20  may be provided within the vacuum conduit to aggregate the solid material vacuumed off of the filter belt. The tanks are all preferably provided with openings, hatches, doors or the like suitable to allow cleaning of the system as required. It has been found using this system and method that the coagulated solids are substantially only lightly adhered to the filter belt and are not embedded therein. This allows the vacuum to easily pull the solids off of the filter belt so that it can be used in continuous operation. 
     It should noted that while aluminum chlorhydrate is the preferred coagulant, other coagulants such as but not limited to aluminum chloride, aluminum sulfate, ferric chloride, ferric sulfate, poly aluminum chloride, clays, sodium aluminate, ULTRA-FLOC, WESTCHLOR, inorganic/polymer blends and suitable combinations thereof, may be utilized without departing from the scope of the invention. It should also be noted that these coagulants may include or be combined to carry iron to create a magnetic flocculent or coagulant.