Patent Abstract:
A system for consolidating and removing contaminate such as paint sludge or oils from a fluid mixture. A contaminate tank receives a supply of the fluid mixture containing contaminate from a source such as a manufacturing line where overspray of paints or cleaning solutions containing washed away oils are collected. A free floating weir floats on the surface of the contaminate tank and mechanically separates and removes contaminate from a surface of the contaminate tank and concentrates the contaminate in a consolidation tank. In the consolidation tanks the contaminate is further separated and collected for disposal.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. Non-Provisional patent application Ser. No. 11/674,309 filed on Feb. 13, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to systems for filtering contaminate such as paint sludge and oil from a solution. 
       BACKGROUND OF THE INVENTION 
       [0003]    During the manufacture of painted parts, such as automotive body parts industrial wastes are produced. By-products such as paint sludge particles and oils are produced and require proper disposal. Systems for concentrating, filtering and removing paint sludge particles and oils from mixtures derived from industrial solutions are necessary to meet environmental standards. 
         [0004]    A common technique for capturing paint overspray/airborne paint particulate produced when operating a paint spray booth is to capture the particulate in a waterfall backdrop within the spray booth. The resulting water-and-particulate fluid mixture is then channeled into a suitable system in which the paint particulate is substantially removed from the water. The filtered water is thereafter advantageously recirculated back to the spray booth&#39;s waterfall backdrop to capture more airborne paint particulate. 
         [0005]    A similar pre-treatment process is used prior to spray painting the part in order to remove oil residue that can be on the surface of the parts either from transport or from the cutting and pressing processes. Similar to the paint process described above, the mixture of oil and solution also needs to be treated. This particular process involves treating or washing the part with a solution to remove the oil residue. The solution with the oil residue is collected and channeled in a manner similar to the painting process described above. 
         [0006]    The paint sludge and oil filtration systems discussed above often require large amounts of solution to be filtered. This in turn requires larger pumps and a larger or greater number of filters if necessary, to be used. Thus it is desirable to design systems that concentrate the contaminate (i.e., paint sludge or oil residue) in order to eliminate filtering and separating large volumes. 
         [0007]    Another problem that can occur is during system shutdowns back pressure in the recycling lines cause mixtures of solution and contaminate to backup into the contaminate tank; it is desirable to have a system that will continue to filter and remove the contaminate in the areas where the backup can occur in order to reduce the energy consumption of the pumps in the system. 
         [0008]    Another issue that can be encountered is that existing systems often lack the ability to adapt to drastic changes in fluid levels in the various tanks or account for foam and other coagulated particles floating on the surface of the solution which can give false readings as to the actual fluid levels in the tanks. 
         [0009]    It is desirable to develop improved systems that separate the paint sludge more effectively. Thus it is desirable to develop systems that can adapt or account for such conditions. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention relates to a system for consolidating and removing contaminate such as paint sludge from a fluid mixture. The system includes a contaminate tank that receives a supply of fluid mixture containing contaminate. A weir is positioned on the surface of the contaminate tank for mechanically separating and removing the contaminate from the surface of the fluid mixture collected in the contaminate tank. A consolidation tank is connected through a series of conduits to the contaminate tank and receives contaminate collected by the weir. The consolidation tank further includes a surface scraper for collecting contaminate proximate to the surface of the consolidation tank and moving the contaminate to a chute. A micro-aeration inlet is connected to the consolidation tank and inputs contaminate from the contaminate tank to the consolidation tank. 
         [0011]    A dissolved gas flotation arrangement having a fluid mixture source, a gas source and an aeration pump creates a dissolved gas mixture from the fluid mixture and gas received from the fluid mixture source is provided. The dissolved gas mixture is input to the consolidation tank through the micro-aeration inlet. A contaminate chute arrangement is connected to the consolidation tank and receives contaminate removed by the surface scraper. The system further includes a pump screen dividing the contaminate tank into a first section where the fluid mixture enters and a second section where a portion of the fluid mixture exits the contamination tank. Additionally, one or more booth pumps are contained in the second section of the contaminate tank for removing a portion of the fluid mixture. 
         [0012]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a schematic view of a first embodiment of the invention; 
           [0015]      FIG. 2  is a schematic view of a second embodiment of the invention; 
           [0016]      FIG. 3  is a schematic view of a third embodiment of the invention; 
           [0017]      FIG. 4  is a schematic view of a fourth embodiment of the invention; 
           [0018]      FIG. 5   a  is an overhead plan view of the floating weir; 
           [0019]      FIG. 5   b  is a perspective view of the suction box of the weir; 
           [0020]      FIG. 5   c  is a cross-sectional side plan view of the floating weir; 
           [0021]      FIG. 6  is a schematic view of a fifth embodiment of the invention; 
           [0022]      FIG. 7  is a schematic view of a conveyorized dryer; 
           [0023]      FIG. 8  is a schematic diagram of a self-dump hopper; 
           [0024]      FIG. 9  is a schematic diagram of a centrifuge dryer; and 
           [0025]      FIG. 10  is a schematic diagram of a dissolved gas flotation arrangement. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0027]    Referring to  FIG. 1  a schematic diagram of a system  10  for consolidating and removing contaminate from a fluid mixture. The fluid mixture containing contaminate such as paint sludge particles or oils contained in a solution, such as water or a hydrophobic wash solution which together form a fluid mixture. The fluid mixture is obtained from the waterfall of a paint spray booth and/or a catch basin for spray painting or washing automotive parts. The waterfall and catch basin is channeled through an inlet pipe  12  or spray header that empties into a contaminate tank  14 . 
         [0028]    The contaminate tank  14  in this particular embodiment is quite large and can hold approximately 5,000 to 150,000 gallons. However, it is possible to a contaminate tank  14  of virtually any size to be used if needed. Within the contaminate tank  14  a stationary weir  16  is positioned to operably align with the surface of the fluid mixture contained in the contaminate tank  14 . The stationary weir  16  has a hinged door  18  that is connected to a float that opens and closes to allow the fluid mixture to enter the stationary weir  16 . When used in a paint sludge removal application the fine particles of paint will float on the surface of the fluid mixture in the contaminate tank  14  and be trapped or gathered by the stationary weir  16  which has the hinged door  18  located adjacent the surface of the fluid mixture. 
         [0029]    The contaminate tank  14  is divided by one or more pump screens  20  so that the contaminate tank has a first section  22  and a second section  24 . The pump screens  20  aid in keeping some of larger particles of paint or booth debris from crossing from the first section  22  into the second section  24 . In the second section  24  is one or more booth pumps  26  which function to recycle or supply solution back to the manufacturing processes. One example is where the booth pumps  26  will pump solution back to the waterfalls in the paint spray booths. Thus it is important to prevent large particles of paint from building up within the second section  24 . 
         [0030]    Despite the fact that the pump screens  20  remove the paint sludge on the surface of the fluid mixture in the second section  24  in order to block the passage of larger paint particles, smaller particles can still pass and enter the booth pumps  26 . This is not usually a problem except when the booth pumps  26  are shutdown the booth pumps  26  and their pipes will drain back into the contaminate tank  14 . As a result some of the finer paint particles that made it past the pump screens  20  may accumulate on the surface of the second section  24 . Thus it is desirable during the shutdown period to prevent damage or overheating of the booth pumps  26  by removing the accumulated paint sludge in the second section  24 . In order to resolve this problem a floating weir  28  is positioned in the second section  24 . The floating weir  24  will operate to remove paint sludge in the second section. 
         [0031]    The floating weir  28  is a free floating weir box that has a hose  30  connecting to the weir box for removing the paint sludge that is collected. The stationary weir and the floating weir  28  both are connected to a vacuum pump assembly  32  that facilitates the removal of the paint sludge and solution that becomes trapped by the stationary weir  16  and floating weir  28 . 
         [0032]    The vacuum pump assembly  32  moves the paint sludge to a consolidation tank  34  where the fluid mixture is more concentrated with paint sludge. The paint sludge will float to the surface of the consolidation tank because the specific gravity of the paint sludge is less than the specific gravity of the solution. At the top of the consolidation tank  34  is a scraper assembly  36  that has a moveable scraper that moves along the surface of the consolidation tank  34 . The scraper assembly  36  pushes the paint sludge into a contaminate chute  38  that empties the paint sludge material into a drying bag  40 . In the drying bag wet paint sludge is gathered. 
         [0033]    The drying bag  40  is porous and allows the solution to drip away from the paint sludge into a drip pan  42  where it can be removed or re-introduced back to the contaminate tank  14 . Once the drying bag  40  has become full it can be removed and the dried paint sludge material can be disposed of. The drying bag  40  can also be contained in a canister  44  that can be heated to facilitate the evaporation or drying process of the paint sludge material. The consolidation tank  34  also has several drains  46  that allow the solution that has been separated from the paint sludge to be re-introduced back to the contaminate tank  14  so that it may ultimately be recycled through the booth pumps  26  back to the paint spray booth. 
         [0034]    Referring now to  FIG. 2  an alternate system is shown. Like reference numerals will be used to indicate structures similar to those shown in  FIG. 1 . A system  100  shown in  FIG. 2  is similar to the system shown in  FIG. 1 . The main difference is that this particular system does not have a stationary weir, but instead has a floating weir  102  within the first section  22  of the contaminate tank  14 . The second section  24  of the contaminate tank does not have a weir box within and only has a single booth pump  26 . The type of system shown in  FIG. 2  would be for a smaller type of operation wherein a lower volume of fluid mixture such as 200-2000 gallons would need to be filtered. However, it is possible to a contaminate tank  14  of virtually any size to be used if needed. 
         [0035]    The type of system depicted in  FIG. 2  provides more level control as well as eliminating the problem of pump cavitation. In paint sludge recovery applications the surface of the contaminate tank  14  can become covered with foam or coagulated paint sludge. This can cause existing paint sludge recovery systems to misread the true fluid levels in the contaminate tank  14 . For example some systems employ a sonic sensor to determine the fluid level. Foam or coagulated paint sludge can give a false reading indicated that the liquid levels in the tank are significantly higher than the true liquid level. The floating weir of the present invention solves this problem because it is always on the surface of the liquid in the contaminate tank  14 . This eliminates any issues of not having enough liquid to supply to the system which can result in cavitation of the pump. Additionally this type of system would allow for the easier re-location or if a user anticipates moving the system to various locations in order to find the “best” location within their facilities. Also this type of system is smaller and would reduce the overall installation costs that would normally be incurred for larger systems. 
         [0036]    Referring now to  FIG. 3  wherein like reference numerals are used to indicate similar structures that were indicated in  FIGS. 1 and 2 . A system  200  is depicted as having a first floating weir  202  positioned in the first section  22  of the contaminate tank  14 . A second floating weir  204  is positioned in the second section  24  of the contaminate tank  14 . The contaminate tank  14  in this type of application could be between 200 and 10,000 gallons. However, it is possible to a contaminate tank  14  of virtually any size to be used if needed. 
         [0037]    This application shown in  FIG. 3  wherein two floating weirs are used is advantageous in systems where there are plants that do not have a central waste treatment system and a large centralized system would not be practical. In large systems as well as other smaller types of systems the systems will be shut down so that the spray booths can be cleaned. During the cleaning process the liquid level in the contaminate tank  14  will rise due to liquid being added from the cleaning process. The only way the liquid level in the contaminate tank  14  returns to normal is for evaporation to occur. In the meantime the system will run with liquid levels that are above the normal operating levels. The use of floating weirs solves this problem because the weir is always as on the surface of the liquid in the contaminate tank  14 . Thus the floating weirs are always at normal operating levels. 
         [0038]    Referring now to  FIG. 4  a schematic embodiment of an oil skimmer system  300  is generally shown. In this particular embodiment a contaminate tank  302  receives a fluid mixture of solution and oils from an auto part treatment booth. Prior to spray paint, auto parts the parts must be washed and treated in order to remove any oil residues that are present on the surface of the part, otherwise the oil residue can cause bubbling or peeling of the paint. The oil residue is often applied during transport in order to prevent the part from rusting or becoming scratched. Secondly oil residues can also sometimes be present as a result of the cutting and pressing processes used to create the part. A solution is used to wash the part to remove the residue from the part surface. This solution is collected in the contaminate tank  302  where the oil can be separated from the solution and the solution can be recycled back to the treatment booth. 
         [0039]    Within the contaminate tank  302  is a floating weir  304  that floats on the surface and skims the oil residue away from a majority of the fluid mixture. Connected to the floating weir  304  is a vacuum hose  306  that leads to a strainer  308  wherein unwanted solid particles are removed prior to filtration. The solid particles can be metal shavings from the cutting and manufacturing process and their removal is important because they can clog or damage the filtration system. After passing through the strainer  308  the oil residue and solution mixture passes through a pump  310  which supplies the suction to the floating weir  304 . The pump  310  in one embodiment can be a diaphragm pump; however, it is possible for virtually any style of pump to be used as long as the pump does not emulsify the solution. The solution is then passed to an oil/water hydrocyclone unit  312  which have one or more filtration columns that separate the oil residue from the solution. After filtration the waste oil progresses to a decant tank where it is further concentrated, collected and separated. The solution that has been separated by the hydrocyclones  314  is removed and re-introduced through a solution outlet  318  back to the contaminate tank  312  wherein a booth pump (not shown) can draw fluid from the contaminate tank  314  and introduce it to the spray headers or educators for agitation at the surface of the part to be washed. 
         [0040]    Referring now to  FIGS. 5   a - 5   c  a floating weir  400  identical to those shown in the embodiments depicted in  FIG. 1-4  is shown in greater detail. The floating weir  400  has a suction box  402  that collects the contaminate (e.g., paint sludge or oils) from the tank that it is position within. The suction box  402  has four hinged doors  404  that each have a float member  406  attached to the back side of each hinged door  404  for controlling the opening and closing of the door. The float members  406  float on the surface of the liquid contained within the suction box  402  in order to control the position of the hinged door  404 . This in turn controls the ingress of fluid from the tank into the suction box  402 . When the fluid levels in the suction box  402  are low the hinged door  404  will be more open and when the fluid levels in the suction box  402  are high the hinged door  404  will be more closed. 
         [0041]    The suction box  402  has an outlet  408  that connects to a vacuum hose for providing suction to the suction box  402 . A lifting eyelet  410  is positioned at the top of the suction box  402  for removing the floating weir  400  from the tank that the floating weir is placed within. The suction box  402  has four flotation canisters  412  which can be filled with air for giving the floating weir  400  buoyancy. Alternatively the flotation canisters  412  can be filled with some other substance that is sufficient to provide buoyancy to the floating weir  400  on the surface of a tank full of fluid. 
         [0042]    The flotation canisters  412  are connected to the suction box  402  by one or more adjustment bands  414  that wrap around each of the flotation canisters and connect through one or more eyelets  416  formed on the exterior surface of the suction box  402 . The suction box  402  is adjustable along the height of the vertical axis Y-Y of the flotation canisters  412  by placing the bands  414  and suction box  402  at a different height. 
         [0043]    Referring now to  FIG. 6 , an alternate system using a dissolved gas flotation arrangement is shown. Like reference numerals will be used to indicate structures similar to those shown in  FIG. 1 . A system  500  is shown as having a consolidation tank  501  that has then modified to include a dissolved gas flotation arrangement  502 . While the present invention describes a consolidation tank  501  and dissolved gas flotation arrangement  502  used in combination with a system having only a stationary weir  16  in the contaminate tank  14 , it is within the scope of this invention for the alternate embodiment to be used in combination with one or more stationary weirs, or a combination of flotation and stationary weirs as set forth of the other embodiments in  FIGS. 1-5 . The use of the consolidation tank  501  in combination with the dissolved gas flotation arrangement  502  injects gas bubbles into the consolidation tank  501  that will further contribute to the separation of the contaminate from the fluid mixture within the consolidation tank  501 . It has been found that introducing dissolved gas will increase the efficiency of the consolidation tank  501  by causing the contaminate particles (e.g. paint sludge to float at the surface of the consolidation tank for removal by the scraper assembly  36 ). As the scraper assembly  36  removes the contaminate, it is deposited into the contaminate chute  38  where it is then introduced to a contaminate treatment device  504 . 
         [0044]      FIG. 10  is a schematic diagram of the dissolved gas flotation arrangement  502  which has a tank wall coupling  506  that serves as a fluid mixture source for the dissolved gas flotation arrangement  502 . Referring to  FIGS. 6 and 10 , the tank wall coupling  506  is connected through the wall of the consolidation tank  501 . The consolidation tank  501  further includes a separator plate  508  that extends vertically through a portion of the consolidation tank and is open near the bottom of the tank to allow fluid mixture that has separated from the solid contaminates to pass under the separator plate. This ensures that the fluid mixture located between the wall of the consolidation tank and the separator plate  508  is generally clean and free of any paint sludge materials. Therefore, the fluid mixture received through the tank wall coupling  506  is generally free of any solid paint sludge material. 
         [0045]    The dissolved gas flotation arrangement  502  further includes a gas source  508 , which in the present embodiment of the invention is an atmospheric air flow meter with a check valve or solenoid valve that controls the flow of air from the atmosphere into the arrangement  502 . While the gas source  508  is described as being a connection to atmosphere, it is possible to use other types of gas sources such a compressed air source or other types of compressed gases. The dissolved gas flotation arrangement  502  further includes an aeration pump  510  that combines and pressurizes the gas and fluid mixture. Operation of the aeration pump  510  creates a vacuum upstream as fluid is drawn in from the tank wall coupling  506 . The vacuum is measured using a first vacuum gauge  512 . The amount of vacuum created is also indicative of the amount of air being brought in thorough the gas source  508  because of the suction created by the aeration pump  510 . The pressure being output from the aeration pump  510  can be measured by a second pressure gauge  514 . 
         [0046]    After the gas and fluid mixture has been combined it is collectively referred to as the dissolve gas, which is then passed through a diaphragm valve  516  onto a connection  518  that is placed within the stream of a micro-aeration inlet  520  that feeds to the consolidation tank  501 . 
         [0047]    The micro-aeration inlet  520  receives fluid mixture containing contaminate from the stationary weir  516 . In other embodiments, the micro-aeration inlet  520  will receive contaminate and fluid mixture from the floating weirs or the combination of the various weirs discussed in the embodiments shown in  FIGS. 1-5 . 
         [0048]    The valve  516  can be any type of suitable one-way valve capable of allowing pressurized gas to pass through the valve to the micro-aeration inlet  520 , but preventing the back-up of fluid through the valve  516 . The present embodiment used a diaphragm valve. However, it is within the scope of this invention for other types of valves to be implemented. 
         [0049]    The connection  518  is any suitable nozzle or outlet for placing the dissolved gas into the stream of fluid flowing trough the micro-aeration inlet  520 . The present invention contemplates the use of compression tubing; however, it is possible for any other suitable tubing to be utilized. 
         [0050]    The aeration pump  510  described in the present invention is contemplated as being an impeller style pump. However, it is within the scope of this invention for any other suitable pump for combining and pressurizing the gas and fluid mixture to be used. For example, other types of pumps such as gerotor or vane pumps could be utilized and are within the scope of this invention. 
         [0051]    In another alternate aspect of the invention, the dissolved gas flotation arrangement  502  further includes additional aeration ports  503  that input dissolved gas mixture directly into different locations within the consolidation tank  501 . This enhances the distribution of dissolved gas in the consolidation tank  501 . 
         [0052]    In another alternate aspect of the present invention, it is optional to provide a chemical injection port  505  for injecting chemicals into the micro-aeration inlet  520 . Chemicals injected are any suitable chemicals, such as polymers, that promote the coagulation and flotation of the paint sludge on the surface of the consolidator  501 . The chemicals can be injected through their own independent injection port  505  or they can be injected into the arrangement  502  prior to the aeration pump  510 . 
         [0053]    Referring now to  FIGS. 7-9 , various contaminate treatment devices are shown. These contaminate treatment devices can be placed at the end of the chute  38  in  FIG. 6  where the contaminate treatment device  504  is located. Alternatively, the contaminate treatment device  504  can be a drying bag  40  as shown in  FIG. 1 . Additionally, the drying bag  40 , shown in  FIGS. 1-3 , can be interchanged with one of the contaminate treatment devices shown in  FIGS. 7-9 .  FIG. 7  depicts a conveyorized dryer  522  for receiving contaminate from the chute  38  and moving the contaminate along the conveyor while being dried and ultimately deposited into a container  524 .  FIG. 8  depicts a self-dump hopper  526  that receives contaminate from the chute  38 . The self-dump hopper  526  allows for the manual removal of the contaminate to a location where the contaminate can be dumped for storage.  FIG. 9  depicts a centrifuge dryer  528  where contaminate enters an opening  530  of the centrifuge and fluid mixture is separated from a first outlet  532  and solid contaminate is removed from a second outlet  534 . While all the above embodiments of the invention discuss specific contaminate treatment desires, it is within the scope of this invention to use virtually any other type of device that dries the contaminate and stores it for removal. 
         [0054]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Technology Classification (CPC): 8