Abstract:
In a cotton gin, water is sprayed into a duct transporting pneumatically conveyed cotton fibers from a gin stand toward a battery condenser to improve the operation of a bale press where the ginned fibers are compacted into a bale. In some embodiments, a taggant is incorporated into the water to mark cotton fibers so threads or fabrics made from the cotton can be identified for quality control purposes. Spray nozzles may deliver water droplets of roughly the same size as the diameter of the cotton fibers. The nozzles may be located on a duct in a location adjacent dead air in the duct to promote coverage of the spray onto the cotton stream. Air may be delivered around the nozzles into the duct to prevent buildup of cotton and debris around the nozzles.

Description:
[0001]    This application is based on Provisional Patent Application 62/179,452, filed May 6, 2015, priority of which is claimed and which is incorporated herein by reference. 
     
    
       [0002]    0.5 This invention relates to a technique for hydrating ginned cotton in a cotton gin. 
       BACKGROUND OF THE INVENTION 
       [0003]    In order to improve operation of gin stands in the ginning of cotton, seed cotton is dried to reduce the water content to low single digits at a location upstream of gin stands where seeds are removed from lint. 
         [0004]    Low water content also helps lint cleaners upstream and downstream of the gin stands to separate seed cotton or cotton from dust and plant parts. Before the lint passes into a bale press, it is desirable to rehumidify the cotton lint so the bale press works efficiently—very dry cotton lint tends to rebound when the bale press retracts. 
         [0005]    A typical gin includes a conduit or duct delivering cotton and propelling air from the gin stands through a downstream cleaner into a battery condenser where a screen allows air to escape thereby forming a cotton batt which slides by gravity down a lint slide into the bale press. The standard technique for rehumidifying cotton is to deliver high humidity air through the bottom of the lint slide so it passes upwardly through the batt whereby some or all of the water condenses on the cotton fibers. 
         [0006]    Large modern commercial gins run about 60 bales/hour while small gins deliver at least 15 bales/hour. A bale is about 500 pounds of lint so the amount of cotton sliding down the lint slide may be in the range of 7500-30,000 pounds per hour or 2-8 pounds per second. One can imagine that getting a substantially uniform dispersion of condensed water on the batt with current equipment is unlikely. 
         [0007]    It has been attempted in the prior art to spray a water taggant solution on a cotton batt as it slides down the lint slide. The results were not satisfactory because the taggant was not found on a disappointingly large fraction of cotton fibers. 
         [0008]    Disclosures of some interest relative to this invention are found in U.S. Pat. Nos. 2,178,539; 2,764,013; 3,717,904; 3,834,869; 4,019,225; 4,074,546; 6,237,195; 6,240,601; 6,314,618; 6,389,647; 6,807,750; 7,591,048; 7,912,653 and 8,091,181 and U.S. Printed Patent Application 2014/0106357. 
       SUMMARY OF THE INVENTION 
       [0009]    As disclosed herein, water is sprayed into an air duct downstream of the gin stands and upstream of the battery condenser while the cotton fibers are being pneumatically transported toward the battery condenser, i.e. while the cotton fibers are suspended in propulsion air. A mind&#39;s eye picture of the cotton/air mixture flowing through the duct is analogous to the worst imaginable blizzard. Flow through the duct may be relatively fast, e.g. 1500-2000′/minute or 25-34′ per second. The amount of cotton flowing through the duct varies, of course, with the capacity of the gin but for common gins is in the range of 2-8 pounds per second. A nozzle assembly is designed to produce water droplets that are of a diameter that is the same order of magnitude than the diameter of ginned cotton fibers. 
         [0010]    It is an object of this invention to provide an improved technique for rehumidifying cotton lint upstream of a bale press. 
         [0011]    A more specific object of this invention is to provide a technique for rehumidifying cotton lint upstream of a bale press in a manner that produces uncommonly consistent dispersion of liquid water onto cotton fibers. 
         [0012]    A further object of this invention is to provide an improved technique for tagging cotton fibers with a material that can later be detected. 
         [0013]    Another object of this invention is to spray water and a solution onto cotton fibers upstream of a bale press. 
         [0014]    These and other objects of this invention will become more fully apparent as this description proceeds. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a schematic view of a cotton gin; 
           [0016]      FIG. 2  is a schematic view of a cleaner downstream of gin stands, a battery condenser, a lint slide and a bale press; 
           [0017]      FIG. 3  is an isometric view of the cleaner of  FIG. 2  and conduit connecting the cleaner with the battery condenser; 
           [0018]      FIG. 4  is a cross-sectional view of  FIG. 3 , taken along line  4 - 4  thereof as viewed in the direction indicated by the arrows to illustrate a nozzle assembly used to rehumidify cotton lint; 
           [0019]      FIG. 5  is a schematic view of part of a modern gin showing another arrangement of duct work downstream of a cleaner that is, in turn, downstream of gin stands; 
           [0020]      FIG. 6  is a broken view of another embodiment of a duct and nozzle array; 
           [0021]      FIG. 7  is a broken view of another embodiment of a duct and nozzle array; 
           [0022]      FIG. 8  is a broken view of another embodiment of a duct and nozzle assembly; 
           [0023]      FIG. 9  is a broken view of another embodiment of a duct and nozzle assembly, and 
           [0024]      FIG. 10  is a cross-sectional view of a nozzle assembly illustrating its connection with a duct. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Referring to  FIGS. 1-4 , a cotton gin  10  may comprise, as major components, a module feeder  12  for disintegrating a cotton module  14 , a transport system  16  for delivering cotton clumps from the module feeder  12  through the various components of the gin  30 . Cotton gins  10  typically include a feed controller  18 , a series of separators or cleaners  20 ,  22  for separating seed cotton or cotton lint from plant debris upstream from one or more gin stands  24  which separate cotton seed from lint. A cleaner  26  downstream of the gin stands  24  may remove any residual dust or plant parts. 
         [0026]    Conveying air introduced in a conventional manner downstream of the gin stands  24  delivers cotton fibers through the cleaner  26  and through a duct  28  leading to a battery condenser  32 . The duct  28  may be a wide rectangular duct which necks down through a transition  30  to a round duct  34 . Inside the battery condenser  32  is a screen  36  or other suitable means for separating conveying air flow cotton lint and producing a cotton batt  38 . The cotton batt  38  slides by gravity along a lint slide  40  into to a bale press  42  where the ginned cotton is compressed into a gin bale. 
         [0027]    Conveying air from the battery condenser  32  passes through a conduit  44  to one or more cyclones  46  for removing dust from the conveying air before exhausting it to the atmosphere. Those skilled in the art will recognize the gin  10  as heretofore described as being typical of modern commercial gins. The disclosures of U.S. Pat. Nos. 8,046,877 and 8,356,389 are incorporated herein by reference for a more complete description of a cotton gin. 
         [0028]    As will be explained more fully hereinafter, a series of nozzle assemblies  48  delivers a water spray into the duct  28  at one or more locations downstream of the gin stands  24 , such as between the gin stands  24  and the lint cleaner  26  or between the lint cleaner  26  and the battery condenser  32 . Downstream of the lint cleaner  26  may be preferred because many lint cleaners are more efficient with drier cotton lint. The water spray may preferably be into the duct  28  upstream of the battery condenser  32  or into the battery condenser  32  upstream of the screen  36  or other device to separate propulsion air from ginned cotton fibers. It may be preferred to have the nozzle assemblies  48  spraying water into the wide rectangular duct  28  because the cotton fibers are traveling at a lower speed than in the smaller round duct  34  where velocities are higher thereby promoting more consistent dispersion of water droplets onto the cotton lint. 
         [0029]    Another advantage of spraying into the wide rectangular duct  28  is there is considerably more room for a large number of nozzle assemblies  48  as compared to the smaller round duct  34  as may be visualized in  FIG. 3 . A further advantage of spraying into the wide rectangular duct  28  is the cotton fibers are more widely separated than in the round duct  34 . For example, saws (not shown) in the cleaner  24  act to separate cotton fibers to allow trash and dust to separate from the fibers and the cotton fibers have not had the opportunity to conglomerate as may occur in the smaller round duct  34 . The direction of water spray may be transverse to the direction of cotton flow to minimize cotton fibers aimed directly at the nozzle assemblies  48 . It may be preferred that water spray is generally perpendicular or obtuse to the direction of cotton flow.  FIG. 3  is a schematic view of a prototype installation in a working gin and suggests that the rectangular duct  28  is upwardly inclined but this was done to provide adequate room for the spray equipment in an existing gin configuration. As explained more fully hereinafter, many different duct work configurations are feasible. 
         [0030]    Referring to  FIG. 4 , each nozzle assembly  48  may comprise a a fitting  50  securing the assembly  48  in any conventional manner in a threaded opening  52  in the duct  28 . The fitting  50  may accordingly comprise an externally and internally threaded bushing receiving an externally threaded nozzle  54  to which is attached a manifold  56 . The nozzle opening  52  may preferably be recessed inside the fitting  30  out of the flow diameter of the duct  28 , i.e. outward of the internal dimension of the duct  28 , to avoid collecting cotton lint on the nozzle  54  and thereby avoiding wet masses of cotton collecting on or clinging to the nozzle  54 . Another technique which may be effective to avoid the accumulation of wet cotton fibers on the nozzle  54  is to provide one or more air leakage passages  58  through the fitting  50  to allow air to be drawn into the recessed cavity adjacent the nozzle end  60 . This acts to dislodge any wet cotton fibers from the nozzle  54  or prevent their accumulation. 
         [0031]    The nozzle  54  is connected to a water supply line  62  and an air supply line  64 . An oddity of the nozzle  54  is that it is capable of delivering very small droplets in the range of 5-25 micron diameter microns which is about the same size as the width or diameter of many cotton fibers. Preferably, the water droplets may be in the range of 5-25 microns and which may preferably be about 8-12 microns in diameter and which may practically be about microns in diameter. Cotton fibers may vary somewhat in diameter but this variation will likely be in the range of 7-22 microns. As pointed out more fully hereinafter, it is believed the size of the water droplets being about the same diameter as the width of the cotton fibers promotes the efficiency of contacting fibers with water droplets. 
         [0032]    The nozzle assemblies  48  can be purchased commercially from such companies as Spray.com of Wheaton, Ill. By controlling the water pressure to the assembly  48  with a regulator  66  and controlling the air pressure at the assembly  48  with a regulator  68 , the size of droplets emitting from the nozzle  54  and the rate of water delivery can be controlled in a conventional manner, i.e. a table may be provided by the manufacturer so that if water pressure is selected and air pressure is selected, the droplet size and water quantity can be dictated. 
         [0033]    To test how consistent water is applied to cotton fibers with the device of  FIGS. 2-4 , a large batch of Pima cotton of fiber lengths in the range of 1.26-1.47 inches was run through a conventional gin  10  and a taggant was delivered through the conduit  62  along with water. The taggant was from a container  70  and the flow rate of the taggant was controlled by an electrically operated valve or flow meter  72 . It will be evident that the pressure regulators  66 ,  68 , valves (not shown) on the water and air lines  62 ,  64 , and the valve  72  may be controlled by a computer (not shown). This allows the taggant to be shut off when cotton flow ceases and matches the amount of taggant delivered through the conduit  62  to the amount of cotton fibers flowing through the duct  28 . A computer controller also allows control over the total amount of water in a gin bale by determining the amount of moisture in cotton upstream of the spray nuzzles, the amount of cotton flowing through the duct and the amount of water being sprayed. The amount of water in the gin bale may accordingly be controlled to be less than limits imposed by customers, industry standards or the like, which limit is currently around 7% by weight. 
         [0034]    Such a taggant may be of any suitable type but, in the test, artificial DNA was used. The DNA taggant was from Applied DNA Science of Stony Brook, N.Y. Thirty two milliliters of DNA in a total of one liter of DNA/water solution was injected per minute into the water conduit  62  and sprayed into the duct  28  in a gin delivering 20 bales/hour of Pima cotton. Thus, 1920 milliliters/hour of the DNA solution was sprayed onto 20 bales/hour or approximately 10,000 pounds/hour of Pima cotton. The DNA solution was diluted by a substantial amount of water, as explained more fully hereinafter, meaning that the concentration of DNA in the DNA solution is susceptible of wide variation because it will be diluted significantly in the spraying operation. 
         [0035]    At a rate of about 350 bales/day, a total of about 10,000 bales of cotton were sprayed with the DNA solution. A total of twelve fiber samples per day were delivered to a laboratory to determine whether the DNA taggant was present on the fiber or a total of about 350 fiber samples. 100% of the fiber samples submitted to the laboratory tested positive for the DNA taggant, Meaning that every tooted fiber had contacted a water droplet. This is difficult for knowledgeable cotton gin people to believe because the number of individual fibers in 10,000 bales of cotton is immense, almost beyond imagination. This is not proof that every fiber in the 10,000 bales had been contacted with water but sophisticated statistical calculations will show, to a very high degree of confidence, that a very large proportion of fibers were contacted with DNA laced water. The exact mechanism that distributes taggant so efficiently is not known and the invention is not bound by any theory. One may surmise that some of the fibers were contacted directly by sprayed taggant but it is not known that all of the tested fibers were contacted directly by sprayed taggant. It is possible that taggant was transferred indirectly to some fibers by a tagged fiber rubbing against an untagged fiber. Given the turmoil of fibers jostling along in a propulsion air stream, this seems possible and perhaps likely. 
         [0036]    It is apparent this technique is a viable approach to mark fibers, including cotton fibers, in a quality control effort. Tagging a select type of cotton fibers with DNA taggants can readily assure that the select type of fibers is present in processed threads or textiles. In addition, it is clearly feasible to spray water onto ginned cotton upstream of a battery condenser with a penetrant, other than a taggant or marker, that has beneficial effects on cotton fibers. The penetrant may be of any suitable type such as a surfactant, wetting agent or the like. 
         [0037]    Another advantage of this invention is that it is much, much cheaper than conventional rehumidifying equipment. The only cost are some commercially available nozzles, a water source, a source of low pressure air, conventional low pressure regulators, valves, a computer controller and the labor to install the equipment. The required water pressure in most applications is well below the pressure of conventional city water systems, meaning that no additional water pumping equipment is necessary. 
         [0038]    Referring to  FIG. 5 , there is illustrated a cotton gin  80  having a differently configured ducting arrangement downstream from a first plurality of cleaners  82  each of which includes an inlet  84  and an outlet  86  which may typically be a rectangular duct similar to the duct  28 . A second plurality of cleaners  88  may be provided which includes an inlet  90  and an outlet  92  which typically may be a rectangular duct similar to the duct  28 . Outlets  86  of the first cleaners  82  may be connected to a valve  94  which may connect one or both of the outlets  86  to an intermediate duct  96  which connects to a second valve  98  which typically may be connected to the outlets  92  of the second cleaners  88 . An outlet conduit  100 , which may be rectangular similar to the duct  28 , from the valve  98  may deliver cotton pneumatically conveyed through the valves  94 ,  98  through a transition  102  to a round duct  104  leading to a battery condenser (not shown) in a manner similar to the gin  10  in  FIGS. 1 and 2 . The gin  80  as heretofore described will be understood by those skilled in the art to be representative of modern high capacity gins where one or a plurality of the cleaners  82 ,  88  may be operating, depending on the volume throughput of the gin  80  and as controlled by the position of the valves  94 ,  98 . 
         [0039]    A series of nozzle assemblies  106  delivers a water spray into the duct  100  at one or more locations downstream of the cleaners  82 ,  88 . It may be preferred to have the nozzle assemblies  108  spraying water into the wide rectangular duct  100  rather than into the round duct  104  for the same reasons it may be desirable to spray water into the rectangular duct  28  rather than the round duct  32 . 
         [0040]    Referring to  FIG. 6 , another embodiment of this invention is illustrated comprising a duct  110  at some location in a cotton gin, such as shown in  FIG. 1 , between the gin stands (not shown) and a lint cleaner (not shown), between the lint cleaner (not shown) and a battery condenser  112  or between the gin stands (not shown) and the battery condenser  112  if no lint cleaner is present. The duct  110  may be rectangular or round and includes an inlet  114 , one or more elbows or bends  116  and an outlet  118  leading to a bale press (not shown). The duct  110  can be horizontal or vertical, meaning that the elbow  116  may change the direction of the duct  110  in a horizontal plane, in a vertical plane or in an inclined plane. The elbow  116  changes the direction of lint flow and an includes an intersecting pipe section or access hatch  120 . The access hatch  120  comprises a curved inlet wall  122  of a thickness similar to the wall  124  of the duct  110  and a straight outlet wall  126  and normally include a hatch cover (not shown) which has been replaced by a nozzle array  128  having thereon a series of nozzle assemblies  130 . One effect of the access hatch  120  is to create a dead air space  132 . 
         [0041]    It may be advantageous to spray water into the dead air space  132  for a variety of reasons. Pressure in the dead air space  132  is lower than atmospheric pressure because of the change of direction of lint flow. This allows outside air to flow, without a fan or pump, past the nozzle assemblies  130  to dislodge cotton or water collecting, or tending to collect, on the nozzle assemblies  130  as will be pointed out more fully hereinafter. Another aspect of the dead air space  132  is that lint flow detaches from the wall  122  along a line or zone  134  leaving the space  132  mostly free of cotton. This allows spray from the nozzle assemblies  130  to spread out before contacting any cotton thereby increasing the ability of the spray to reach most or all of the cotton fibers. Another advantage of the dead air space  132  is to allow ambient air to enter the duct  110  and thereby flow past the nozzle assemblies  130  in order to dislodge or prevent the accumulation of debris on the assemblies  130 . 
         [0042]    Referring to Figure /, there is illustrated another approach to create a dead air space into which water spray may be directed. A round or pipe shaped duct  136  is located between the gin stands and the battery condenser and includes an inlet  138 , an enlarged section  140  and an outlet  142 . Because of the increase in diameter of the pipe wall  144  at a location  146 , a dead air space  148  is created where the lint detaches from the wall  144  along a line  150  downstream of the location  146 . The dead air space  148  is roughly annular because the duct  136  is round. 
         [0043]    It will be apparent that many different approaches may be devised to create a dead air space in a duct of a pneumatic conveyor, as by the provision of a compartment  152  opening into a duct  154  as shown in  FIG. 8 , particularly when an axis  156  of the opening  158  is inclined in the direction  160  of flow thereby producing a venturi like affect to reduce the pressure adjacent the end of the nozzle assembly  160 . It will be seen that lint flow in the duct  154  detaches from the wall  162  along a line or zone  164  creating a dead air space  166  inside the duct  154 . It will be apparent there are many other ways to create a dead air space adjacent a nozzle. For example, vanes or other obstructions upstream of a nozzle may be used to divert the air/lint stream away from the wall of a straight duct and thereby create a dead air space into which the nozzle sprays. 
         [0044]    Some of the effects of a dead air space can be created by forcibly blowing air into a duct  168  as shown in  FIG. 9 . A conduit  170  opens into the duct  168  and houses a nozzle assembly  172  and a fan  174  driven by a motor (not shown). Air blowing into the duct  168  depresses lint flowing through the duct  168  along a line or zone  176  to create a zone or area  178  which allows spray from the nozzle assembly  172  to spread out in much the same manner that a dead air zone allows spray to spread out and increase the fraction of cotton fibers contacted by water. Because of the direction of flow in the duct  168 , the zone  178  may typically be skewed in the downstream direction. 
         [0045]    Referring to  FIG. 10 , there is illustrated an exemplary nozzle assembly  180  mounted on or adjacent an opening  182  in a duct  184  by a bracket  186  affixed to the duct  184  in any convenient manner. A nozzle  188  may preferably be removably attached to the bracket  186  as by mating threads  190 . A manifold  192  attaches to the bracket  186  and/or nozzle  188  in any suitable manner and includes an air connection  194  and a water connection  196  separately connected to the nozzle  188  through fittings  198 ,  200 . The end  202  of the nozzle  188  will be seen to be outboard, or spaced from, the interior wall  204  of the duct  184  to reduce the accumulation of cotton lint or debris on the nozzle  188 . The opening  182  allows outside ambient air to flow into the duct  184  around the nozzle end  202  thereby cleaning the nozzle end  202  and dislodging any cotton lint or debris attempting to collect on the nozzle  188 . 
         [0046]    It may be desirable to employ filters to remove particles in the same range or larger than the water droplets emitting from the spray nozzles. To this end, referring to  FIG. 4 , a filter  202  may be employed in the air line  64  to remove particles from the air stream. Similarly, a filter  204  may be employed in the water line  62  to remove particles from the water source. The filters  202 ,  204  may preferably remove particles of any desired size, such as 1-20 micron, thereby eliminating two sources of dust in the baled cotton. Commercially available filters down to one micron are available and may be used. Five micron filters have proved successful. 
         [0047]    It may be desirable to employ a heater in the water supply to minimize the effects of operating in abnormally cold climates or during an abnormally cold time of the year. To this end, a heater  206  may be incorporated in the water supply line  62 . 
         [0048]    Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms is only by way of example and that numerous changes in the details of operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereafter claimed.