This invention relates to an improved electrostatic method and apparatus for treating material, such as for electrostatically removing retained liquid from web-like liquid-bearing material of the liquid absorbing type. Background Art It is well known from applicant's U.S.

Patent No. 4,551,924, and its chain of related issued U.S. patents set forth therein, that it is believed that liquid in liquid-bearing material of the liquid- absorbing type can be moved relative to that material when the liquid-bearing material is passed through a plurality of non-uniform electrostatic fields so that the fields at least partially extend through the material to act on at least part of the retained liquid thereof to move at least part of the retained liquid relative to the material.

It is also a feature of applicant's aforementioned U.S. patent to illustrate and describe the above liquid-moving feature in combination with conventional heating methods and apparatus for removing retained liquid from web- like liquid-bearing material of the liquid- absorbing type as the material is being substantially continuously moved therein to improve upon such conventional heating methods and apparatus .

In particular, it was believed according to such aforementioned U.S. patent that at least some of the aforementioned features can be obtained by merely disposing an electrode arrangement

adjacent an existing heated surface to augment the drying effect of the heated surface.

For example, the electrode arrangement can cooperate with the heated surface to define a plurality of alternately arranged non-uniform electrostatic fields extending between the electrode arrangement and the surface, with each non-uniform field having the higher intensity portion thereof substantially oppositely located relative to the higher intensity portion of an adjacent non-uniform field so that the fields can at least partially extend through a material to be dried when the material is disposed against the surface and between the surface and the electrode arrangement.

Such heated surface could be an existing drier drum known as a "can" or "yankee" in the paper making industry and the material to be dried can be the paper webs normally being dried by such heated drums. Of course, this invention is not to be limited to the paper industry as it is believed that the features of this invention can be utilized with almost any type of drying system.

It was also believed according to such aforementioned U.S. patent that the aforementioned electrode arrangement for an existing dryer drum need not define a plurality of alternately arranged non-uniform electrostatic fields, but that the same can define a plurality of alternately directed and oppositely charged electrostatic fields that are serially arranged, with the positively charged portion of every other field at the electrode means being adjacent and between the negatively charged portions of the two fields adjacent thereto at the electrode means in a like repeating pattern.

For example, such electrode means can comprise a plurality of like electrodes disposed in an arcuate pattern outboard of the dryer drum, transverse to the direction of rotation of the dryer drum, parallel to each other and extending across the width of the web of material that is being dried thereby. Disclosure of the Invention

It is a feature of this invention to utilize such an electrode arrangement with infrared heater means.

In particular, according to one aspect of this invention, there is provided an infrared heating apparatus for drying moisture-bearing material, the apparatus comprising a hood means having an open end facing one side of the moisture- bearing material, means in the hood means for directing infrared heating energy from the hood means out through the open end thereof, insulation means substantially closing the open end of the hood means and transmitting the infrared heating energy therethrough to the moisture-bearing material to tend to dry the same, and means for causing relative movement between the moisture bearing material and the open end of the hood means, with the improvement comprising electrostatic means carried by the hood means for creating a plurality of electrostatic fields through which at least the one side of the moisture-bearing material, in effect, passes as the moisture-bearing material is being heated by the infrared heating-energy and the relative movement is being provided between the moisture bearing material and the hood means. Therefore, it is an object of this

invention to provide an improved method and/or apparatus for drying material, the method and/or apparatus of this invention having one or more of the novel features of this invention as set forth above or hereinafter shown or described.

In particular, pursuant to another aspect of this invention, there is provided an infrared heating method for drying moisture-bearing material, said method comprising the steps of providing a hood means having an open end facing one side of said moisture-bearing material, providing means in said hood means for directing infrared heating energy from said hood means out through said open end thereof, providing insulation means to substantially close said open end of said hood means and transmit said infrared heating energy therethrough to said moisture-bearing material to tend to dry the same, and causing relative movement between said moisture-bearing material and said open end of said hood means, the improvement comprising the step of providing electrostatic means to be carried by said hood means for creating a plurality of electrostatic fields through which at least said one side of said moisture-bearing material, in effect, passes as said moisture-bearing material is being heated by said infrared heating-energy and said relative movement is being provided between said moisture- bearing material and said hood means. Brief Description of the Drawing

The features of the invention, and its technical advantages, can be seen from the following description of preferred embodiments, together with the claims and the accompanying drawing, in which:

FIG. 1 is a view similar to FIG. 14 of applicant's aforementioned U.S. Patent No. 4,551,924, and illustrates and embodiment of the method and apparatus of this invention; FIG. 2 is a fragmentary cross-sectional perspective view of another embodiment of the method and apparatus of this invention;

FIG. 3 is a fragmentary cross-sectional view taken on line 3-3 of FIG. 2; FIG. 4 is a view similar to FIG. 3, and illustrates another embodiment of the method and apparatus of this invention; and

FIG. 5 is a fragmentary cross-sectional view taken on line 5-5 of FIG. 4. Best Modes for Carrying Out the Invention

While the various features of this invention are hereinafter described and illustrated as being particularly adapted to provide means for removing liquid from wet fibrous material, such as a wet paper web, it is to be understood that the various features of this invention may be utilized singly or in any combination thereof to remove liquid from other types of material, as desired.

Therefore, this invention is not to be limited to only the embodiments illustrated in the drawing, because the drawing is merely utilized to illustrate one of the wide variety of uses of this invention.

Since this invention is an improvement of the methods and apparatus illustrated and described in applicant ' s aforementioned U. S. Patent No. 4, 551, 924, such U.S. Patent No. 4, 551,924, in its entirety, is being incorporated into this disclosure for background information. Therefore, it can be seen that in the

embodiments illustrated in the FIGS. 9-14 of U.S. Patent No. 4,551,924, as well as in the embodiments illustrated in FIGS. 4, 7 and 8 thereof wherein insulating barriers 27 are being utilized, and improved method for drying material is provided therein and comprises the steps of disposing the material 11 in a heating means to have the heating means heat at least part of the liquid particles of the material 11, disposing charged electrode means 23 or 22 and 23 so as to be adjacent one side of the material 11 when the material 11 is disposed in a heating means and to define a plurality of electrostatic fields 26 that are serially arranged in substantially a like repeating pattern and that are substantially constant and non-oscillating so that the fields 26 at least partially extend through the material 11 when the material 11 is disposed in the heating means, moving the material 11 in one direction through the heating means to cause at least a portion of the material 11 to have the particles of liquid thereof serially moved through the electrostatic fields 26 while the portion of the material 11 is being heated in the heating means whereby the electrostatic fields 26 augment the drying effect of the heating means on the material 11, and disposing means 27 or 41 between each pair of adjacent electrostatic fields 26 to change the normal shape of the adjacent electrostatic fields 26 between the electrode means 23 or 22 and 23 and the material 11 so that when the material 11 is moved in the one direction, the particles of liquid of the portion serially move through the thus reshaped electrostatic fields 26 while the portion of the material 11 is being heated by the heating means.

Also, it can be seen that the barriers 27 in FIG. 4, of U.S. Patent 4,551,924, as well as in FIGS. 9, 10, 11 and 12 thereof, provide a generally non-field area between each pair of adjacent electrostatic fields whereby the electrostatic fields are spaced apart by the non-field areas so that when the material 11 is moved in one direction, the portion of the material 11 will have the particles of liquid thereof serially moved through an electrostatic field 26 into a non-field area and then into the next electrostatic field 26 in a repetitive manner whereby the particles of liquid of the portion of the material 11 are subjected to a pumping action by the thus spaced apart substantially constant and non-oscillating electrostatic fields 26 while the portion of the material 11 is being heated by the heating means.

Of course, it was pointed out in the U.S. Patent No. 4,551,924, that alternating current can be utilized to alternately charge the electrodes 23 and/or 22, if desired, but that such an arrangement would be current-consuming and not non-current consuming as would be the case if direct current were merely utilized. Thus, with direct current it is believed that the fields 26 will be non-current consuming and thereby be constant or non- oscillating fields 26 whereas with alternating current it is believed that the fields 26 will be current consuming as the fields 26 would be non- constant or oscillating fields 26.

In addition, it was pointed out in U.S.

Patent No. 4,551,924, that while the insulating barriers 27 of FIGS. 9 and 11 thereof are shown as pairs of members between adjacent electrodes 23, such pairs of barriers 27 could actually be nozzle

means through which heated or unheated air or other fluid could be directed against the respective side of the material 11 in the manner represented by the arrows 50 in FIGS. 9 and 11 thereof to impinge against the material 11 and then flow away from the same in the manner represented by the arrows 51 in FIGS. 9 and 11 thereof. It was also pointed out in U.S. Patent No. 4,551,924, that if such fluid is heated, then such nozzle means would at least form part of the.heating means for the material 11, that fluid could be directed between the barriers 27 in the manner of the arrows 50 without the barriers 27 being nozzle means, if desired, and that such air flow 50 could be pulsed to vibrate the material 11 for the reasons set forth therein.

Thus, it can be seen that the fluid flowing between the barriers 27 and the material 11 as represented by the arrows 52 in FIGS. 9 and 11 of the U.S. Patent No. 4,551,924, will keep the material 11 out of contact with the barriers 27, as well as the electrodes 23, in much the same manner as air float systems (or even float the air directing nozzles relative thereto) and it might be found that as the air flows from the material 11 outwardly past the electrodes 23 in the direction of the arrows 51, such air flow 51 will keep the electrodes 23 clean and moisture free by carrying away any particles that might be attracted thereto.

Of course, the barriers 27 and electrodes 23 could be arranged in a self-contained unit to be disposed in the desired heating means or apparatus adjacent the material 11 therein, as desired, regardless of whether or not the barriers 27 are utilized with the air flow means 50. Also, while the insulating means disposed

between each adjacent pair of the electrode means of U.S. Patent No. 4,551,924 are illustrated as being a part separate from the electrode means, it is a feature of this invention to have the insulating means secured to the electrode means and have opening means passing transversely through the insulating means through which heated or unheated air can pass to impinge against the material to be dried thereby, whereby, such insulating means comprises nozzle means as well as means for reshaping the electrostatic fields.

For example, reference is now made to FIG. 1 wherein an embodiment of the method and apparatus of this invention is generally indicated by the reference numeral 60 and is being utilized to dry the web 11 as the same passes from left to right through the apparatus 60 in a manner similar to- the embodiments illustrated in FIGS. 11-14 of U.S. Patent No. 4,551,924. In particular, a plurality of electrodes

23 are disposed in spaced parallel relation to the side 45 of the material 11, and the material 11 is being heated by heated air that is directed against the side 45 of the material as represented by the arrows 61 in FIG. 1. The heated air 61 passes through suitable openings 62 formed through a sheet 63 of electrically insulating material that also has the electrodes 23 embedded therein to insulate the same. The electrodes 23 in FIG. 1 are charged in an alternating manner of negative, positive, negative, etc. as described in U.S. Patent No. 4,551,924, to create a plurality of electrostatic fields 26 that are arranged so that each pair of adjacent fields 26 have the field lines of force

thereof acting in substantially opposite directions on the web 11 for the reasons set forth in U.S. Patent No. 4,551,924.

The sheet 63 of electrically insulating 5 material has opposed flat parallel sides 64 and 65, and the electrodes 23 are embedded therein in such a manner that the same are disposed closer to the surface 64 than to the surface 65 so that the electrostatic fields 26 will tend to concentrate in Q the web 11 in the manner illustrated in FIG. 1 rather than extend out of the side 65 of the sheet

63. In addition, the amount of insulating material o the sheet 63 that is disposed between adjacent electrodes 23 is substantially greater than the 5 ^" amount of insulating material between those electrodes 23 and the side 64 of the sheet 23 so that the tendency for the electrostatic fields 26 is to form the pattern illustrated in FIG. 1.

Therefore, it can be seen that the 0 openings 62 through the sheet means 63 of FIG. 1 define nozzle means that are disposed between adjacent electrostatic fields 26 (when the fields 26 are considered as being adjacent in the manner of FIG. 13 of U.S. Patent No. 4,551,924). These 5 nozzle means are adapted to have a fluid from a suitable source (not shown) flow therethrough as indicated by the arrows 61 to impinge against the material 11 to act on the material 11 at the same time that the fields 26 are acting thereon. Also, 0 it can be seen that the sheet means 63 acts as harrier means between adjacent electrodes 23 to reshape the electrostatic fields 26 as described in U.S. Patent No. 4,551,924.

While the electrodes 23 of FIG. 1 are all 35 disposed on one side 45 of the material 11, it is

to be understood that the electrodes 23 of FIG. 1 can cooperate with electrodes disposed on the other side 44 of the material 11 in the same manner that the electrodes 23 of FIG. 11 of U.S. Patent No. 4,551,924 act on opposite sides 44 and 45 of the material 11 to define the electrostatic fields 26 that extend transversely across the sheet of material 11. The other electrodes that are disposed adjacent the side 44 of the web of material 11 could also be disposed in a sheet of insulating material that has openings passing therethrough in the same manner as the sheet of material 63 illustrated in FIG. 1, if desired.

While the various embodiments of the invention of U.S. Patent No. 4,551,924 are described as having the heating means either be heated air, so as to heat the sheet of material by convection, or has the heating means comprise the heated drum 20, so as to heat the sheet of material by conduction, it is a feature of this invention to utilize an infrared heating means in combination with an electrostatic arrangement.

For example, it is well known that infrared heating means have been provided for heating wet sheets of material, wherein the infrared heating means comprises a plurality of spaced parallel infrared heating units, such as high frequency Quartz lamps, disposed substantially parallel to the longitudinal axis of the sheet of material that is being heated thereby, with an insulating sheet, such as a Quartz sheet, being disposed between the wet sheet of material and the infrared heating elements. For example, such an infrared heating unit is sold by Impact Systems, Inc., of San Jose, California, USA, and such a

heating method and apparatus is generally indicated by the reference numeral 70 in FIGS. 2 and 3.

The infrared heating apparatus and method 70 of FIGS. 2 and 3 has been modified according to the teachings of this invention to include electrostatic means to be utilized therewith as hereinafter described. Thus, the resulting method and apparatus of FIGS. 2 and 3 comprise a method and apparatus of this invention that is generally indicated by the reference numeral 71 in FIGS. 2 and 3.

The method and apparatus 71 of this invention includes a hood structure 72 having an open end 72' adapted to be disposed closely adjacent the side 45 of a sheet of moisture-bearing material 11 that is moved relative to the frame 72 along a longitudinal axis 75 in a desired direction while the unit 70 heats the material 11 by the electrically operated infrared heating elements 76 in a manner well known in the art, the elements 76 being disposed in spaced parallel relation to each other and being substantially parallel to the axis 75, with each element 76 having opposed ends 77 and

78 carried by end sections 79 and 80 of the hood means 72 in a manner well known in the art so that electrical current can pass through the elements 76 to create the infrared heating waves that are well known in the art. The heating elements 76 direct the infrared energy thereof through a "window" 81 and against the side 45 of the sheet 11. The hood means 72 carries the .sheet of insulating material 81, such as Quartz, that extends between the ends

79 and 80 of the hood means 72 to close the open end 72' thereof, and through which the radiant energy passes to heat the web 11 as the web 11

passes under the hood 72 in a manner well known in the art.

The hood 72 has air flowing therethrough to keep the elements 76 from becoming too hot. The air flowing across the elements 76 is normally under pressure so as to be forced out of the interior chamber 82 of the hood 72 through suitable slits or openings 83 formed through the sheet of material 81 in any suitable manner. As previously stated, it is one feature of this invention to include electrostatic field means with the hood 72 of the prior known method and apparatus 70 to form the new method and apparatus 71 of this invention. In particular, a plurality of electrodes

23 of this invention are disposed in spaced parallel relation against the bottom side 84 of the sheet of material 81 in such a manner that the same ^■ are sandwiched between the side 84 of the sheet of material 81, and another sheet of insulating material 85 that can be of the same material as the sheet 81 or different, as desired, and can have transverse grooves 86 formed therein in the manner illustrated in FIG. 3 to accommodate the electrodes 23 so that the facing side 87 of the sheet of material 85 can abut the side 84 of the sheet of material 81 as illustrated in FIGS. 2 and 3. The sheet of material 85 can be held by the same frame flanges 72" that hold the original sheet of material 81 as illustrated in FIG. 2. The electrodes 23 can be charged either all with a like charge or with the alternate positive, negative, positive, etc. charging previously described so as to generate the electrostatic fields 26 illustrated in FIG. 3 which operate on the sheet of material 11

in the same manner as the fields 26 previously described while the infrared heating elements 76 are heating the sheet of material 11, so that the electrostatic fields 26 of the method and apparatus 71 augment the drying effect of the heating elements 76 on the sheet of material 11 in the manner described in U.S. Patent No. 4,551,924. The additional sheet of material 85 of this invention has suitable slots or openings 88 that pass therethrough and are aligned with the slots or opening means 83 of the sheet of material 81, so that the combined opening means 83, 88 define nozzle means that are disposed between the electrode means 23 and through which heated air will pass from the interior of the hood 72 to the side 45 of the sheet of material 11 in the manner represented by the arrows 89 in FIG. 3. Thus, it can be seen that the arrangement illustrated in FIG. 3 is similar to the arrangement illustrated in FIG. 1, with the addition of the infrared heating elements 76 disposed on that side of the sheet of material carrying the electrodes 23 opposite to the side thereof that faces the wet web of material 11. In this manner, it can be seen that existing hoods 2ne» hoods 72 can be modified by merely adding the additional sheet of material 85 and the electrodes 23 to the already existing sheet of material 81 thereof, and by providing suitable electrical interconnections to the electrodes 23 to charge the electrodes 23 in the desired manner. Thus, the arrangement 70 can be modified to produce the method and apparatus 71 of this invention wherein the electrostatic fields 26 augment the heating effect of the infrared heaters 76 for the reasons set forth in U.S. Patent No. 4,551,924.

While the electrodes 23 of the method and apparatus 71 of FIGS. 2 and 3 have been shown as being transverse to the heating elements 76, the electrodes 23 could be arranged parallel with the heating elements 76 and between the same in the manner illustrated in FIGS. 4 and 5, wherein the elements 76 would provide sufficient insulation between the electrodes 23 so that the electrodes 23 could be disposed on top of the upper surface 90 of the sheet of material 81 and could act through the sheet of material 81 to form the electrostatic fields 26 in the manner illustrated in FIGS. 4 and 5, whereby the additional sheet of material 85 may not be needed. Also, while the method and apparatus 71 of this invention have been illustrated with the electrodes 23 only being disposed on one side 45 of the sheet of material 11, it is to be understood that other electrodes could be disposed on the other side 44 of the sheet of material 11 to cooperate with the electrodes 23 in the same manner as the arrangement illustrated in FIG. 11 of U.S. Patent No. 4,551,924, or as in the other FIGS, of the drawings thereof, as desired. In addition, it is to be understood that the electrode arrangement disposed on the side 44 of the sheet of material 11 remote from the hood 72 could be utilized without utilizing the electrode arrangement in the hood 72, if desired. Accordingly, it can be seen that it is believed that this invention provides improved methods and apparatus for drying material and the like.

While the forms and methods of this invention, now preferred, have been illustrated and

described as required, it is to be understood that other forms and method steps can be utilized and still fall within the scope of the appended claims.