Systems and methods for electrostatically individualizing and aligning fibers

Abstract

Various systems and methods described herein use electrostatic forces to separate fibers with minimal to no breakage and align the individual fibers with minimal handling. These systems and methods allow for testing, such as measuring the length, of individual fibers without the biases caused by breakage or bundling in prior art systems. These systems and methods may also be useful in applications requiring fiber alignment with minimal material handling. One exemplary system includes a pair of nip rollers and a collector that are spaced apart from each other to define an air gap therebetween. The nip rollers are grounded or negatively charged, for example, and the collector is positively charged to create an electrostatic field in the air gap. The electrostatic field separates the fibers, elongates the fibers end to end, and urges the fibers toward the collector.

1 . An apparatus for separating and aligning an individual fiber sample comprising:
 at least one pair of nip rollers comprising a first nip roller and a second nip roller; and   a collector spaced apart from an exit side of the pair of nip rollers, the exit side of the pair of nip rollers and an entry side of the collector defining an air gap there between, wherein an electrostatic field is created within the air gap between the nip rollers and the collector,   wherein the electrostatic field separates the one or more fibers from each other as the one or more fibers enter the air gap, elongates the one or more fibers end to end in the air gap between the exit side of the nip rollers and the entry side of the collector, and urges the one or more fibers toward the collector.   
     
     
         2 . The apparatus  claim 1 , wherein the nip rollers are negatively charged or grounded and the collector is positively charged. 
     
     
         3 . The apparatus of  claim 1 , wherein the nip rollers are negatively charged and the collector is positively charged, and the nip rollers induce a negative electrical charge on one or more fibers moving between the nip rollers from an entry side of the nip rollers to the exit side of the nip rollers. 
     
     
         4 . The apparatus of  claim 1 , wherein the nip rollers are positively charged and the collector is negatively charged or grounded, and the nip rollers induce a positive electrical charge on one or more fibers moving between the nip rollers from an entry side of the nip rollers to the exit side of the nip rollers. 
     
     
         5 . The apparatus of  claim 1 , wherein an axis of rotation of the first nip roller is vertically aligned with an axis of rotation of the second nip roller, and a direction of rotation of the first nip roller is opposite a direction of rotation of the second nip roller. 
     
     
         6 . The apparatus of  claim 5 , wherein the collector comprises a collection roller, and an axis of rotation of the collection roller is horizontally aligned with a plane that extends between the first and second nip rollers. 
     
     
         7 . The apparatus of  claim 6 , wherein the second nip roller is disposed vertically below the first nip roller, and a direction of rotation of the second nip roller is the same as the direction of rotation of the collection roller. 
     
     
         8 . The apparatus of  claim 7 , further comprising at least one motor that drives rotation of one of the first or the second nip roller. 
     
     
         9 . The apparatus of  claim 1 , wherein a width of the air gap between the exit side of the nip rollers and the entry side of the collector is greater than a maximum length of fiber to be passed through the apparatus. 
     
     
         10 . The apparatus of  claim 1 , further comprising an imaging device, wherein the imaging device has a field of view comprising at least a portion of the air gap and is configured for capturing image signals of the one or more fibers in the air gap. 
     
     
         11 . The apparatus of  claim 10 , wherein the image signals are received by a computer processing unit, and the computer processing unit is configured for identifying a length of each of the one or more fibers from the image signals. 
     
     
         12 . The apparatus of  claim 11 , wherein the computer processing unit is further configured for identifying a diameter of each of the one or more fibers from the image signals. 
     
     
         13 . The apparatus of  claim 10 , wherein the image signals are received by a computer processing unit, and the computer processing unit is configured for identifying a diameter of each of the one or more fibers from the image signals. 
     
     
         14 . The apparatus of  claim 10 , further comprising:
 a suction collection device disposed adjacent an exit side of the collector, the suction collection device urging the one or more fibers into the suction collection device after the one or more fibers have passed through the air gap, and a computer processing unit configured for adjusting a suction power of the suction collection device and receiving image signals from the imaging device.   
     
     
         15 . The apparatus of  claim 14 , wherein the computer processing unit is further configured for adjusting a voltage difference from a power supply that creates the electrostatic field between the nip rollers and the collector. 
     
     
         16 . The apparatus of  claim 1 , further comprising a computer processing unit configured for adjusting a voltage difference from a power supply that creates the electrostatic field between the nip rollers and the collector. 
     
     
         17 . The apparatus of  claim 1 , further comprising a suction collection device disposed adjacent an exit side of the collector, the suction collection device urging the one or more fibers into the suction collection device after the one or more fibers have passed through the air gap. 
     
     
         18 . The apparatus of  claim 1 , further comprising one or more additional pairs of nip rollers adjacent to and upstream of the entry side of the first and second nip rollers. 
     
     
         19 . The apparatus of  claim 1 , wherein the collector comprises a stationary collection plate. 
     
     
         20 . The apparatus of  claim 19 , wherein the collection plate is disposed on an exterior, vertical entry face of a non-conductive housing, the entry face defining a slot extending horizontally along at least a portion of the entry face and through the entry face such that the air gap is in fluid communication with an interior of the housing, the slot being defined adjacent an edge of the collection plate, and the entry face facing the exit side of the nip rollers, wherein fibers F passing through the air gap pass through the slot into the interior of the housing. 
     
     
         21 . The apparatus of  claim 20 , wherein a suction device is coupled to the housing such that the suction device is in fluid communication with the interior of the housing, the suction device configured for evacuating fibers F within the interior of the housing. 
     
     
         22 . The apparatus of  claim 20 , further comprising a fringe roller having an axis of rotation and an outer surface, the outer surface of the fringe roller being disposed adjacent the exit side of the second nip roller in the air gap, a direction of rotation of the fringe roller being the same as the direction of rotation of the second nip roller, and at least a portion of the outer surface of the fringe roller defining a combing surface, the combing surface being configured for urging a fiber into the air gap from the exit side of the nip rollers when the fringe roller is rotated. 
     
     
         23 . The apparatus of  claim 1 , further comprising a fringe roller having an axis of rotation and an outer surface, the outer surface of the fringe roller being disposed adjacent the exit side of the second nip roller in the air gap, a direction of rotation of the fringe roller being the same as the direction of rotation of the second nip roller, and at least a portion of the outer surface of the fringe roller defining a combing surface, the combing surface being configured for urging a fiber into the air gap from the exit side of the nip rollers when the fringe roller is rotated. 
     
     
         24 . The apparatus of  claim 1 , wherein the at least one pair of nip rollers comprises a first pair of nip rollers and a second pair of nip rollers that are horizontally spaced apart from each other, each pair of nip rollers includes the first nip roller and the second nip roller, a first apron extends around and couples a portion of an outer diameter of the first nip rollers and a second apron extends around an outer diameter of each of the second nip rollers. 
     
     
         25 . A method of separating and aligning an individual fiber sample comprising:
 rotating a pair of nip rollers, an exit side of the nip rollers being spaced apart from an entry side of a collector to define an air gap there between,   creating an electrostatic field between the collector and the nip rollers; and   feeding a beard of fibers between the nip rollers,   wherein:
 the electrostatic field separates the fibers, elongates the fibers end to end between the exit side of the nip rollers and the entry side of the collector, and urges the fibers toward the collector, and 
 a width of the air gap from the exit side of the nip rollers to the entry side of the collector is larger than a maximum length of any fiber within the beard of fibers. 
   
     
     
         26 . The method of  claim 25 , further comprising capturing image signals of the separated and elongated fibers in the air gap with an imaging device, the imaging device having a field of view that comprises at least a portion of the air gap. 
     
     
         27 . The method of  claim 26 , further comprising identifying a length of each separated fiber using the image signals. 
     
     
         28 . The method of  claim 27 , further comprising identifying a diameter of each separated fiber using the image signals. 
     
     
         29 . The method of  claim 25 , wherein creating an electrostatic field between the collector and nip rollers comprises applying a positive electrical charge to the collector and grounding or applying a negative electrical charge to the nip rollers. 
     
     
         30 . The method of  claim 25 , wherein creating an electrostatic field between the collector and nip rollers comprises grounding or applying a negative electrical charge to the collector and applying a positive electrical charge to the nip rollers. 
     
     
         31 . The method of  claim 25 , wherein creating an electrostatic field comprises applying a voltage difference between the nip rollers and the collector. 
     
     
         32 . The method of  claim 25 , wherein the collector comprises a collection roller. 
     
     
         33 . The method of  claim 25 , wherein the collector comprises a stationary collection plate. 
     
     
         34 . The method of  claim 25 , further comprising rotating a fringe roller through a first angle to capture an entry end of a fiber exiting the exit side of the nip rollers and through a second angle to present the fiber further into the air gap, wherein an outer surface of the fringe roller is disposed adjacent the exit side of the nip rollers, and at least a portion of the outer surface of the fringe roller defines a combing surface, the combing surface being configured for capturing the fiber when the fringe roller is rotated through the first angle and urging the fiber further into the air gap from the exit side of the nip rollers when the fringe roller is rotated through the second angle.