Grounded magnetic device for removing static charges

Abstract

A device for removing static charges from a moving paper web includes two grounded and shielded permanent magnets with means to support each magnet on opposite sides of the moving web with the polarities of each magnet so oriented that the charge-neutral center plane of the magnet is perpendicular to the path of the web. The device removes static charges by exposing the paper web to a grounded magnetic field first of one polarity and then to a grounded magnetic field of the opposite polarity.

We claim: 
     
       1. Apparatus for removing static electrical charges on a moving web passing therebetween, comprising in combination a pair of elongated magnetic device of substantially equal length, each of said pair of devices including   an elongated end-to-end assembly of substantially rectangular permanently magnetic blocks of equal height and thickness, assembled with magnetic poles of one polarity aligned along the length of one side of said elongated assembly and magnetic poles of the opposite polarity aligned along the length of the opposite side of said elongated assembly;   said assembled blocks having two end surfaces and four side surfaces, and a means to provide for grounding of each said assembly,   said assembled blocks having magnetic shielding on two opposite side surfaces and on one intermediate side surface, and being exposed on the other intermediate side surface, together with   means to position the two said devices spaced narrowly apart in parallel alignment with their like polarities opposite each other so oriented as to provide a substantially common charge-neutral plane perpendicular to the path of such web. .Iadd.   
     
     
       2.  A process for removing a static electrical charge on a material as the material moves in response to a material moving apparatus, the process comprising the steps of: positioning a magnet adjacent to the material moving apparatus; wherein the magnet produces a magnetic filed having first and second polarities;   grounding the magnet to provide a grounded magnetic field having said first and second polarities; and   moving the material and the magnet relative to each other so that the material passes through the first polarity of the grounded magnetic field and thereafter passes through the second polarity of the grounded magnetic field. .Iaddend..Iadd.3. The process of claim 2 wherein the positioning step further comprises the step of positioning the magnet wherein the magnet produces a magnetic field having a field strength of at least 390 mTesla. .Iaddend..Iadd.4. The process of claim 3 wherein the positioning step comprises the step of positioning a permanent magnet adjacent to the material moving apparatus; and wherein the grounding step comprises the step of grounding said magnet. .Iaddend..Iadd.5. The process of claim 4 wherein the moving step further comprises the step of moving the material   
     
     
        along a path spaced from the magnet. .Iaddend..Iadd.6.  The process of claim 5 further comprising the steps of: positioning a second magnet adjacent to the first mentioned magnet; wherein the second magnet produces a magnetic field having first and second polarities corresponding to the first and second polarities of the first mentioned magnet;   grounding the second magnet to provide a grounded magnetic field; and   moving the material and both said magnets relative to each other so that the material passes between said magnets. .Iaddend..Iadd.7. The process of claim 3 wherein the moving step further comprises the step of moving the material along a path spaced from the magnet. .Iaddend..Iadd.8. The process of claim 2 wherein the positioning step further comprises the step of positioning the magnet wherein the magnet produces a magnetic field having a nominal field strength of 390 mTesla. .Iaddend..Iadd.9. The process of claim 2 wherein the positioning step comprises the step of positioning a permanent magnet adjacent to the material moving apparatus; and wherein the grounding step comprises the step of grounding said magnet. .Iaddend..Iadd.10. The process of claim 2 wherein the positioning step comprises the step of positioning an elongated permanent magnet adjacent to the material moving apparatus; wherein said magnet has a   
     
     
        length greater than a width of the material. .Iaddend..Iadd.11.  The process of claim 2 wherein the positioning step comprises the step of positioning an elongated permanent magnet adjacent to the material moving apparatus; wherein the length of said magnet is about 2 inches longer than the width of the material. .Iaddend..Iadd.12. The process of claim 2 wherein the moving step further comprises the step of moving the material along a path spaced from the magnet. .Iaddend..Iadd.13. The process of claim 2 wherein the positioning step further comprises the step of positioning the magnet wherein the magnet produces a magnetic field having a charge-neutral plane and wherein the moving step further comprises the step of moving the material along a path perpendicular to the charge-neutral plane. .Iaddend..Iadd.14. The process of claim 2 further comprising the steps of: positioning a second magnet adjacent to the first mentioned magnet; wherein the second magnet produces a magnetic field having first and second polarities corresponding to the first and second polarities of the first mentioned magnet;   grounding the second magnet to provide a grounded magnetic field; and   moving the material and both said magnets relative to each other so that   
     
     
        the material passes between said magnets. .Iaddend..Iadd.15.  A process for removing a static electrical charge on a material as the material moves in response to a material moving apparatus, the process comprising the steps of: positioning a magnet adjacent to the material moving apparatus; wherein the magnet produces a magnetic field having a field strength of at least about 390 mTesla; and   moving the material and the magnet relative to each other so that the material passes through the magnetic field. .Iaddend..Iadd.16. The process of claim 15 wherein the positioning step comprises the step of positioning a permanent magnet adjacent to the material moving apparatus. .Iaddend..Iadd.17. The process of claim 15 wherein the positioning step comprises the step of positioning an elongated permanent magnet adjacent to the material moving apparatus; wherein said magnet has a length greater than a width of the material. .Iaddend..Iadd.18. The process of claim 15 wherein the moving step further comprises the step of moving the material along a path spaced from the magnet. .Iaddend..Iadd.19. The process of claim 15 wherein the positioning step further comprises the step of positioning the magnet wherein the magnet produces a magnetic field having a charge-neutral plane and wherein the moving step further comprises the step of moving the material along a path perpendicular to the   
     
     
        charge-neutral plane. .Iaddend..Iadd.20.  The process of claim 15 further comprising the steps of: positioning a second magnet adjacent to the first mentioned magnet; wherein the second magnet produces a second magnetic field;   grounding the second magnet to provide a grounded magnetic field; and   moving the material and both said magnets relative to each other so that the material passes between said magnets. .Iaddend..Iadd.21. Charge removing apparatus for removing a static electrical charge on a material as the material moves along a path in response to the material moving apparatus, the charge removing apparatus comprising:   a magnet positioned along the path of the material; wherein the magnet produces a magnetic field having first and second polarities; and   an electrical ground connected to the magnet to provide a grounded magnetic field having said first and second polarities;   said magnet positioned to produce the magnetic field in the path of the material such that, as the material moves relative to the magnet in response to the material moving apparatus, the material passes through the grounded magnetic field of the first polarity and thereafter passes through the grounded magnetic field of the second polarity. .Iaddend..Iadd.22. The charge removing apparatus of claim 21 wherein the magnet produces a magnetic field having a field strength of at least 390   
     
     
        mTesla. .Iaddend..Iadd.23.  The charge removing apparatus of claim 21 wherein the magnet comprises a permanent magnet positioned adjacent to the material moving apparatus along the path of the material; and wherein the electrical ground is connected to said magnet. .Iaddend..Iadd.24. The charge removing apparatus of claim 21 wherein the magnet comprises an elongated permanent magnet positioned adjacent to the material moving apparatus along the path of the material; and wherein said magnet has a length greater than a width of the material. .Iaddend..Iadd.25. The charge removing apparatus of claim 21 wherein the position of the magnet is spaced from the path of the material. .Iaddend..Iadd.26. The charge removing apparatus of claim 21 wherein the magnet produces a magnetic field having a charge-neutral plane; and wherein the magnet is positioned such that the charge-neutral plane is perpendicular to the path of the material. .Iaddend..Iadd.27. The charge removing apparatus of claim 21 further comprising: a second magnet positioned adjacent to the first mentioned magnet;   wherein the second magnet produces a magnetic field having first and second polarities corresponding to the first and second polarities of the first mentioned magnet; and   an electrical ground connected to the second magnet to provide a grounded magnetic field;   wherein the path of the material runs between said magnets.   
     
     
        .Iaddend..Iadd. 8.  Charge removing apparatus for removing a static electrical charge on a material as the material moves along a path in response to a material moving apparatus, the charge removing apparatus comprising: a magnet positioned along the path of the material;   wherein the magnet produces a magnetic field having a field strength of at least about 390 mTesla;   said magnet positioned to induce the magnetic field in the path of the material such that, as the material moves relative to the magnet in response to the material moving apparatus, the material passes through the magnetic field. .Iaddend..Iadd.29. The charge removing apparatus of claim 28 wherein the magnet comprises a permanent magnet positioned along the path of the material. .Iaddend..Iadd.30. The charge removing apparatus of claim 28 wherein the magnet comprises an elongated permanent magnet positioned along the path of the material; wherein said magnet has a length greater than a width of the material. .Iaddend..Iadd.31. The charge removing apparatus of claim 28 wherein the position of the magnet is spaced from the path of the material. .Iaddend..Iadd.32. The charge removing apparatus of claim 28 wherein the magnetic field produced by the magnet has a charge-neutral plane; and wherein the magnet is positioned such that the charge-neutral plane is perpendicular to the path of the   
     
     
        material. .Iaddend..Iadd.33.  The charge removing apparatus of claim 28 further comprising: a second magnet positioned adjacent to the first mentioned magnet; and   an electrical ground connected to the second magnet to provide a grounded magnetic field;   wherein both said magnets are positioned with their respective magnetic fields in the path of the material such that, as the material moves relative to the magnets in response to the material moving apparatus, the material passes through the magnetic fields. .Iaddend..Iadd.34. Charge removing apparatus for removing a static electrical charge on a material as the material moves along a path, the charge removing apparatus comprising:   a first magnet positioned along and spaced from the path of the material;   a second magnet positioned adjacent to the first magnet; wherein the magnetic poles of the first magnet are aligned with the corresponding magnetic poles of the second magnet;   an electrical ground connected to the first and second magnets wherein said magnets and ground provide a grounded magnetic field having afield strength of at least about 390 mTesla; and   means for moving the material and said magnets relative to each other so that the material passes between said magnets and through the grounded   
     
     
        magnetic field. .Iaddend..Iadd.35.  Charge removing apparatus for removing a static electrical charge on a web of paper as the paper moves along a path through a printing press, the charge removing apparatus comprising: a magnet positioned along the path of the web;   wherein the magnet provides a magnetic field having a field strength of at least about 390 mTesla; and   wherein said magnet is positioned with the magnetic field in the path of the web such that, as the web moves along the path through the printing press, the web passes through the magnetic field. .Iaddend..Iadd.36. Charge removing apparatus for removing a static electrical charge on a paper comprising:   a paper moving apparatus;   a magnet positioned adjacent to the paper moving apparatus; and   an electrical ground connected to the magnet;   wherein the magnet and ground provide a grounded magnetic field having a field strength of at least about 390 mTesla; and   wherein the paper moving apparatus moves the paper and the magnet relative to each other so that the paper passes through the grounded magnetic field. .Iaddend..Iadd.37. Charge removing apparatus for removing a static electrical charge on a material, the charge removing apparatus comprising:   a magnet to produce a magnetic field having a field strength of at least about 390 mTesla;   an electrical ground connected to the magnet to provide a grounded magnetic field; and   means for moving the material and the magnet relative to each other so that the material passes through the grounded magnetic field. .Iaddend.