Patent Publication Number: US-2017348703-A1

Title: Particle separation system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 14/279,952 filed May 16, 2014, the disclosure of which is hereby incorporated in its entirety by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a particle separator that is configured to remove magnetic and non-magnetic conductive particles from a liquid. 
     BACKGROUND 
     Automobile body-in-white units accumulate metal particulates during the manufacturing and assembly processes such as weld balls, metal shavings, metal dust, and the like. The metal particulates may cause several different issues when they remain on an e-coated automobile body including, surface defects, star bursting, and galvanic corrosion. 
     The metal particulates may be removed from automobile bodies in the paint shop, during the phosphate coating and e-coating stages. The phosphate coating and e-coating systems are then filtered to remove the metal particulates. 
     Automobile bodies have traditionally been made from ferrous metals but may now include non-ferrous materials as well. It would be desirable to provide a particle separation system that removes ferrous metal particulates and non-ferrous material particulates from the phosphate coating and e-coating systems. 
     SUMMARY 
     A method includes flowing a magnetic and non-magnetic particle-containing liquid across a rotor that has alternating pole electromagnets, energizing the electromagnets and rotating the rotor to generate a changing magnetic field to generate eddy currents in the non-magnetic particles, repelling the non-magnetic particles to a collection point by the changing magnetic field, directing the magnetic particles from the electromagnets to the collection point, and removing the magnetic and non-magnetic particles from the collection point. 
     A method includes flowing a magnetic and non-magnetic particle-containing liquid into a housing and across a rotor that has alternating pole electromagnets, energizing the electromagnets and rotating the rotor to generate a changing magnetic field that generates eddy currents in the non-magnetic particles, repelling the non-magnetic particles to a housing bottom by the changing magnetic field, directing the magnetic particles from the electromagnets to the bottom, and removing the magnetic and non-magnetic particles from the bottom. 
     A method includes flowing a magnetic and non-magnetic particle-containing liquid into a separator and across a rotor having a plurality of electromagnets arranged with alternating poles, energizing the electromagnets to generate a magnetic field, rotating the rotor to alter the magnetic field such that the magnetic field generates eddy currents in the non-magnetic particles, repelling the non-magnetic particles to a tapered bottom of the separator by the magnetic field, de-energizing the electromagnets to direct magnetic particles from the electromagnets to the bottom, and opening a valve to flush the particles out of the bottom. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic view of particle separator made according to one example of this disclosure; 
         FIG. 2  is a diagrammatic view of a particle separation system for removing magnetic and non-magnetic conductive particles from a liquid coating; and 
         FIG. 3  is a flowchart illustrating a method for removing magnetic and non-magnetic conductive particles from a liquid. 
     
    
    
     DETAILED DESCRIPTION 
     The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts. 
     Referring to  FIG. 1 , a particle separator  10  is disclosed that is configured to remove magnetic particles and non-magnetic conductive particles from a flowing liquid. Magnetic particles include ferrous metals such as iron or steel, and any other metal, alloy, or material that is capable of being attracted by a magnet. Non-magnetic conductive particles include metals such as aluminum, aluminum alloys, magnesium, magnesium alloys, copper, copper alloys, zinc, zinc alloys, brass, and any other conductive metal, alloy, or material that is not capable or only negligibly capable of being attracted by a magnet. 
     The particle separator  10  consists of a housing  12  that contains a rotor  14 . The rotor  14  has a plurality of magnetic sections  16  that have alternating poles. The particle separator  10 , in the alternative, may be comprised of more than one rotor  14  that each has a plurality of magnetic sections  16  with alternating poles. The housing  12  has an inlet  18  and an outlet  20  where the liquid containing magnetic and non-magnetic particles may flow into and out of the housing  12 , respectively. The inlet  18  is located upstream of the rotor  14 . The outlet  20  is located downstream of the rotor  14 . 
     A drive  22  is configured to rotate the rotor  14  about a pivot  24 . The pivot  24  is shown orientated vertically, but may have other orientations including a horizontal orientation. The rotor  14 , when rotated, generates a changing magnetic field. The drive  22  may consist of an external power source such an electric motor, internal combustion engine, turbine, or any other power source capable of generating a rotational motion. A gear or pulley system may be used to transmit the energy from the power source to the rotor  14 . In the alternative, the drive  22  may consist of a series of fins (not shown) that are attached to the rotor  14  so that the flowing liquid pushes against the fins causing the rotor  14  to rotate. 
     The magnetic particles and non-magnetic conductive particles are removed from the liquid as it flows through the particle separator  10 . The liquid initially flows into the particle separator  10  at the inlet  18 . Magnetic particles are removed from the liquid by being attracted and attached to the plurality of magnetic sections  16 . Non-magnetic conductive particles are removed from the liquid by being repelled away from the rotor  14  in a direction away from the flow of the liquid by the changing magnetic field. The non-magnetic conductive particles may be directed toward a collection point  26  when they are repelled by the changing magnetic field. The changing magnetic field induces an eddy current inside the non-magnetic conductive particles which are then repelled away from the rotor  14  according to Lenz&#39;s Law. Lenz&#39;s law states that the current induced due to a change or a motion in a magnetic field is so directed as to oppose the change in flux or to exert a mechanical force opposing the motion. The liquid then flows out of the particle separator  10  at the outlet  20  with the magnetic and non-magnetic conductive particles removed. 
     The plurality of magnetic sections  16  may be any type of magnet, including permanent magnets or electromagnets that are energized by a DC power source  28 . Electromagnets, however, may be advantageous for maintenance purposes, because the plurality of magnetic sections  16  may be de-energized if they are comprised of electromagnets. The particle separator  10  may then be backwashed, while the plurality of magnetic sections  16  are de-energized, in order to remove the magnetic particles that have attached to the plurality of magnetic sections  16 . If the plurality of magnetic sections  16  are comprised of permanent magnets, the rotor  14  would need to be removed from the particle separator  10  and be power washed to remove the magnetic particles attached to the plurality of magnetic sections  16 . 
     The magnetic particles may also be directed toward the collection point  26  when the particle separator  10  is backwashed. The collection point  26  may include a valve  30  for flushing the magnetic and non-magnetic particles out of the particle separator  10  that are collected at the collection point  26 . 
     Referring to  FIG. 2 , a particle separation system  32  is illustrated for removing magnetic and non-magnetic conductive particles from an immersion tank  34 . A vehicle body-in-white  36  is dipped into to the immersion tank  34  via a conveyer system  38 . The vehicle body-in-white  36  may be a car body, truck cabin, truck bed, or any other part of a vehicle body that goes through a coating process. The immersion tank  34  contains a liquid coating  40  such as a phosphate pretreatment coating or electrophoretic coating (e-coating). The pretreatment coating may, in the alternative, be any type of pretreatment coating for vehicle body-in-white  36 , such as Zirconium Oxide. 
     Phosphate coatings are used on metal parts for corrosion resistance, lubricity, or as a foundation for subsequent coatings or painting. Phosphate coatings are a conversion coating including a dilute solution of phosphoric acid and phosphate salts that is applied via spraying or immersion and chemically reacts with the surface of the part being coated to form a layer of insoluble, crystalline phosphates. 
     Electrophoretic coatings are an emulsion of organic resins and de-ionized water in a stable condition. The electrophoretic coating solution also comprises solvent and ionic components. When a DC voltage is applied across two immersed electrodes, the current flow causes electrolysis of the water. This results in oxygen gas being liberated at the anode (positive electrode) and hydrogen gas being liberated at the cathode (negative electrode). The release of these gases disturbs the hydrogen ion equilibrium in the water immediately surrounding the electrodes. This results in a corresponding pH change and de-stabilizes the paint components of the solution that are coagulated onto the appropriate electrode. 
     An unfinished product is immersed in a bath containing the electrophoretic paint emulsion, and then an electric current is passed through both the product and the emulsion. The paint particles that are in contact with the product adhere to the surface and build up an electrically insulating layer. This layer prevents any further electrical current passing through, resulting in a level coating even in the recessed parts of complex-shaped goods. 
     With continued reference to  FIG. 2 , magnetic and non-magnetic conductive particles that have accumulated on the vehicle body-in-white  36  during the manufacturing and assembly processes are removed from the vehicle body-in-white  36  and transferred into the liquid coating  40  inside the immersion tank  34 . The liquid coating  40  is then pumped into the particle separator  10 , via a first pump  42 , through a first channel  44 . The magnetic and non-magnetic conductive particles are removed from the liquid coating  40  by the particle separator  10 , as described above. The liquid coating  40  is then pumped back into the immersion tank  34 , via a second pump  46 , through a second channel  48 . 
     A scrap bin  50  may be utilized to collect the magnetic and non-magnetic particles that are flushed out of the particle separator  10  when the valve  30  is opened. If the plurality of magnetic sections  16  are electromagnets, the DC power can be left on while the non-magnetic conductive particles are flushed out. The DC power may then be turned off and the magnetic particles flushed out. This allows for separation of the magnetic and non-magnetic conductive particles for ease of recycling and disposing. 
     Referring to  FIG. 3 , a method  52  of removing magnetic and non-magnetic conductive particles from a liquid is illustrated. At step  54  the liquid is supplied to a particle separator. The particle separator has a plurality of magnets that are arranged with alternating poles. The plurality of magnets are rotated about a pivot and generate a changing magnetic field at step  56 . At step  58  the plurality of magnets attract and collect magnetic particles. The magnetic particles attach to the plurality of magnets. At step  60  the changing magnetic field generates eddy currents in the non-magnetic conductive particles. The changing magnetic field then repels the non-magnetic conductive particles in a direction away from the flow of the liquid at step  62 . The liquid then flows out of the particle separator at step  64 . The magnetic and non-magnetic conductive particles are directed to collection point in the particle separator at step  66  and are flushed out of the particle separator at step  68 . 
     The embodiments described above are specific examples that do not describe all possible forms of the disclosure. The features of the illustrated embodiments may be combined to form further embodiments of the disclosed concepts. The words used in the specification are words of description rather than limitation. The scope of the following claims is broader than the specifically disclosed embodiments and also includes modifications of the illustrated embodiments.