Static cleaning and dust and particle removal

April 25, 1961 s. m. schwartz et al 2,980,933

STATIC CLEANING AND DUST AND PARTICLE REMOVAL

Filed Nov. 8, 1955 _{4 sfceets}__{Sheet χ}

VOLTAGE

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INVENTORS

JAMuEL M. ECMVAOTZ dan/el aeoEs

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Arrofwer

April 25, 1961 _s. _M. schwartz etal 2,980,933

STATIC CLEANING AND DUST AND PARTICLE REMOVAL

Filed Nov. 8, 1955 _{4 Ske}et_s-Sheet 2

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April 25, 1961 _{s> Mi} schwartz etal 2,980,933

STATIC CLEANING AND DUST AND PARTICLE REMOVAL rued «0,. 3, _{1966 4 She8ls}._{sheet s}

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April 25, 1961 s. _M schwartz etal 2,980,933

STATIC CLEANING AND DUST AND PARTICLE REMOVAL

Filed Nov. 8, 1955 _{A ςΗΩο+Ε}. ~ _{+ λ}⁹ 4 Sneets-Sheet 4

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United States Patent Office _{p a Δ}²’^980>933

Patented Apr. 25, 1961

2,980,933

STATIC CLEANING AND DUST AND PARTICLE REMOVAL

Samuel M. Schwartz, Paterson, N.J., and Daniel Gross, Passaic, NJ. (both % Velveray Corporation, Brighton Ave. and Walnut St., Clifton, NJ.)

Filed Nov. 8, 1955, Ser. No. 545,604

Claims. (Cl. 15—1.5)

The present invention relates to apparatus for cleaning or removing fine particles, and it particularly relates to apparatus for cleaning sheet materials or webs whether of paper, sheet plastic materials, laminated materials, knitted, woven and netted textiles and the cleaning thereof from finely divided solid materials which may be carried thereupon on the surface thereof in the meshes or pores thereof.

Although the present invention has broad application to the removal of solid particles of all kinds such as metallic or inorganic, it will be particularly described in its utilization in connection with the cleansing and dedusting of the web or sheet materials from organic dusts or particles.

It is among the objects of the present invention to provide a speedy, reliable, low-cost, high production system of removing finely divided particles which may closely adhere to, become enmeshed in the openings, or entangled in the interestices in sheet materials.

In many types of web materials, particularly those of nitrogenous materials, it has been found that finely divided particles of dirt and soil very closely adhere to the surface and in the interstices thereof with the result that sometimes it is almost impossible to remove the undesirable dirt, dust and residual unattached particles therefrom without causing subtantial abrasion or wearing ⁴⁰of the material.

It is among the further objects of the present invention to provide a dirt or fibre removal apparatus which will quickly and accurately remove a large portion or all of the adhering dirt, dust and adherent or loose particles ⁴⁵without any substantial wear or friction upon the fibres, filaments or mesh of the web material itself, and with further assurance that the removal will be so complete as not to require any subsequent wet-cleansing or scouring operations. SO

Furthermore, with many types of fabrics when strongly brushed or beaten to cause removal of dirt, dust or adherent or loose particles, it has been found that such mechanical treatment results in further driving of a great deal or substantial part of the adhering dust, dirt or adherent or loose particles into the mesh or interstices of the material, and it is among the further objects of the present invention to provide an efficacious, low-cost, highly effective, quick removal apparatus which will quickly eliminate and remove the residual dirt, dust and adherent ⁶⁰or loose particles without damage to the material and without requiring any particular manual operation.

Still further objects and advantages will appear in the more detailed description set forth below, it being understood, however, that this more detailed description is 55 given by way of illustration and explanation only and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention as claimed. 70

A static charge may be applied while the web or sheet material is passing in any direction, as for example either ² horizontally or diagonally, but it has ben found most suitable and most useful to pass the web or sheet material vertically between oppositely charged high potential static charges.

This is desirably accomplished while a stream of air is being drawn across the face of the web or sheet material and desirably obliquely across the mesh or interestices thereof.

This will result in an almost immediate removal of all 10 undesirable dust, dirt and adherent or loose particles.

For example, the web may first be pased through a static field in one direction of 20 to 40,000 static volts and be in this field during such passage for one-half to two to three seconds, and then it may be immediately 15 passed through an oppositely charged static field for the same length of time and with the same potential of charge.

However, in a preferred embodiment of the present invention, two reverse fields have been found to be suf20 ficient with the second field exceeding the first field by 10 to 20,000 volts and using shorter application in them.

'During this treatment it is most important the static charge be concentrated laterally across the web and transversely of the direction of the movement of the web 25 rather than parallel to the direction of the movement of the web.

To assure most effective treatment it has been found that the web should be passed between two closely spaced electrode members, one electrode member consisting of a ³⁰ metal plate slightly wider than the width of the web, the length of which will determine the period of application of the charge, while the other electrode should consist of a plurality of bars of desirably hollow triangular shape with their flat sides adjacent to the passing fabric and closely spaced by a distance say of 1 to 2 inches.

Opposite charge application then is attained when the same electrode combinations are reversely placed on opposite sides of the web.

To prevent any breakdown or sparking which might injure the web it has been found desirable to apply fairly thick glass plates to at least one of the electrodes and desirably over the metal plate electrode. These glass plates should desirably extend beyond the electrode by a distance of at least 1 inch on all sides, and desirably may be of a thickness of glass of % to 2 inches.

It has been found that this will effectively prevent any breakdown or excessive sparking of the high static potential, and the fabric will be well protected against any injury due to sparking or any uneven electrical discharge.

With the foregoing and other objects in view the invention consists of the novel construction, combination and arrangement of parts as hereinafter more specifically described, and illustrated in the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, variations and modifications· can be resorted to which fall within the scope of the claims hereunto appended.

In the drawings wherein like reference characters denote corresponding parts throughout the several views:

Fig. 1 is a diagrammatic side sectional view of a web cleaning system showing the application of the electrostatic cleaner of the present invention as a final operation.

Fig. 2 is a diagrammatic side sectional view illustrating an alternative static cleaner arrangement.

Fig. 3 is a side diagrammatic sectional view showing still another alternative static cleaner arrangement.

Fig. 4 is a side sectional view upon a greatly enlarged scale as compared to Fig. 2 of the static cleaner arrangement shown in Fig. 2.

Fig. 5 is a side sectional view of an alternative mechanical beater arrangement to replace or to be used in addi-

2,980,933 . 3 tion to the multiple brushing arrangement at the left of Fig. 4.

Fig. 6 is a transvertical sectional view taken upon the line 6—6 of Fig. 4 and upon an enlarged scale as compared to Fig. 4.

Fig. 7 is a side sectional view upon an enlarged scale of an alternative form of static cleaner arrangement.

Fig. 8 is a side sectional view of still another alternative form of static cleaner arrangement.

Fig. 9 is a diagrammatic side sectional view of one of the transverse bars of one separated electrode construction.

Fig. 10 is a diagrammatic side sectional view of an alternative beating and static cleaner arrangement in which the web is passed through the beating and electrostatic chambers in horizontal position.

Fig. 11 is a diagrammatic side sectional view similar to Fig. 10 of an alternative embodiment in which the brushing chambers and electrostatic cleaning chambers, ate so arranged that the web will pass in a direct line and horizontally through such chambers.

Fig. 12 is a diagrammatic side sectional view of still another embodiment in which the web is first passed through a beater at an upper level and then through an electrostatic cleaner at a lower level.

Fig. 13 is a diagrammatic sectional view showing the direction of the major lines of electrostatic forces where opposite plate and bar electrodes are employed.

Fig. 14 is a diagrammatic side sectional view showing an alternative arrangement of electrostatic electrodes with the lines of force extending in concentrated pattern and directed transversely to the web.

Fig. 15 is a diagrammatic side sectional view showing the lines of force extending obliquely between staggered electrostatic electrodes.

Referring to Fig. 1 there is shown a web or sheet material which may be treated and then festooned¹ and dried.

The web is passed into a drying chamber C and there is subjected to a mechanical excess dust and dirt removal device D followed by the static cleaner operation

E to which the present invention is particularly directed.

The web after prior processing then passes over the guide pulley 26 and is preliminarily lopped at 27. It then passes over the two pulleys 28 and 29 into the drying chamber C.

The chamber C has triangular carrier device 50 which passes around the pulleys 51, 52 and 53, by which carrier device the web is draped as indicated at 54 and 55 upon a series of poles 56.

These poles are carried up and placed upon the carrier belt 57 which is carried on the pulleys 58 and 59.

The length of the chamber C is shown greatly shortened and the web will pass in the draped condition as indicated at 55 through a long chamber until it has been thoroughly dried.

The web then passes over the pulley 60 and under the lip 61 to the outlet 62 of the chamber C. The poles 56 will have been removed from the web and the web will then pass into the mechanical treatment chamber.

It first passes under the pulley 64 and then between the alternating brushes 65, 66, 67, 68, 69, 70 and 71. Desirably a strong air current flows through the chamber 63 to remove any of the dust or dirt which has been mechanically eliminated.

The web will then pass out of the chamber 63 by way of the pulley 72 and will then pass down over the pulley 73 into the static cleaner chamber 74.

In the static cleaner chamber 74 the web will first pass downwardly between the separated electrode 75 and the solid electrode 76. Then the charge will be reversed and the web will pass between the separated electrode 77 and the solid electrode 78. A current of air will be drawn through the chamber and transversely across the web as it is passing downwardly in the direction 79.

The web will then pass downwardly out of the chamber at 80, over the pulley 81, and then upwardly as indi4 cated at 82 and will be wound or rolled as indicated at 83 as a cleaned material. The rollers 84 and 85 will control the rolling up operation.

It has been found that tire successive mechanical brush5 ing at D and the static application at E will remove up to about 85 to 95% and sometimes even up to 100% of all adherent or loose particles, no matter how deeply such particles may have been held within the pores or interstices of the web.

In the embodiment of Fig. 2 the web G enters into the brushing chamber H and then into the static chamber J. It will be noted that the web first passes down through the chamber H entering at 100, and it will then be subjected to treatment by opposite and alternating brushes 15 101, 102, 103, 104 and 105 as it passes downwardly as indicated by the arrow 106.

The web will exit at 107 and pass over the pulleys 108 and 109 and upwardly into the chamber of the static cleaner J.

In passing upwardly as indicated at 110, between the solid electrode 111 and the separated electrode 112, and then between the solid electrode 113 and the separated electrode 114 which are arranged reversely to electrodes 111 and 112, substantially all residual dirt, dust and par25 ticles will be removed.

The web then passes over the pulleys 115 and 116 and downwardly over the pulley 117 until it is rolled up at 118 upon the rollers 119 and 120.

In the alternative arrangement of Fig. 3, the web K 30 will pass into the right angular chamber L which has a mechanical cleaning unit M and a static cleaning unit N.

It will pass into this chamber L through the opening 130 and then past the alternating brushes 131, 132, 133, 134 and 135. These brushes will loosen any partly held 35 flock and also they will remove a great deal of the loose flock that may also drive in some loose dust and dirt which will have to be subsequently removed by the static cleaner N.

This same operation will also occur in connection with 40 the brushing arrangement D of Fig.l and the brushing arrangement H of Fig. 2.

The web will then pass over the pulley 136 and downwardly between the separated electrode 137 and the solid electrode 138. Beyond the electrodes 137 and 138 it will pass between the solid electrode 139 and the separated 45 electrode 140, out through the opening 141 and over the pulley 142.

The cleaned web will then be rolled up as indicated at 143 upon the rolls 144 and 145.

Fig. 4 shows the combination mechanical and static 50 cleaner of Fig. 2 upon a substantially enlarged scale.

The pulley 99 is mounted upon the bracket 98 upon the top wall 97 of the chamber H. The sidewalls 96 and 95 will carry the exhaust connections 94 and 93 and they will be removable by bolts 92 and 91.

There will be a strong suction of air through the connections 93 and 94 which will be drawn out by a section source indicated at 92, which may consist of a high powered fan or.reversed blower.

As a result the air will be drawn into the chamber H at the upper opening 100 and the lower opening 107, and it will be drawn both upwardly and downwardly across the fabric and then transversely through the interstices and then into the exhaust connections 93 and 94.

The air will also be drawn over the brushes 101, 102, 65 103, 104 and 105 and will aid in cleaning any excess flocking away from the brushes.

. The belt 91 will drive the rotary brushes 101 to 105 and it will pass over the intermediate idle pulleys 90 and 89. The lower pulley 108 will be carried on the bracket 70 88 on the bottom plate 87 of the casing H.

In the static cleaner I there will be a similar arrangement. The top plate 150 will carry a bracket 151 for the pulleys 115 and 116.

The separated electrodes 112 and 114 will consist of 5 bars 152 and 153 which are mounted upon the insulat5 »,980,938 cate with the exhaust main 260, which leads at 261 to an exhaust fan or reverse blower.

The air will be drawn in great velocity through the openings 256 and 252 through the right angle chamber, and any residual dust and dirt will be picked up and discharged at 261.

The alternative embodiment of Fig. 8 is very similar to that of Fig. 7, except that instead of the brushes 230 to 234 of Fig. 7 there will be provided hexagonal cross section beaters 280, 281, 282, 283 and 284.

These beaters will be in the mechanical cleaning chamber V of the L-shaped chamber or box W, which has the static cleaner X'

All of the transverse electrodes or electrode bars as indicated at 75, 77, 112, 114, 137, 140, 180, 244 and 245 consist of hollow bars as indicated at 180 in Fig. 9, with the cross section being triangular or trapezoidal.

The electrodes as shown in Figs. 1 to 8 being in small scale are shown solid but it is understood that they are all hollow as indicated in Fig. 9.

The web Y will enter through the opening 285 and then will pass between the hexagonal beaters 280 to 284 and will be subjected to suction at the connections 286 and 287, and will then pass over the pulley 288 and between the separated electrode 289 and the plate electrode 290 where it will be subjected to suction through the connection 291 positioned at about mid-height of the separated electrode 289.

The static cleaner of Fig. 8 may be of the same construction as the static cleaners shown in Fig. 4 and Fig. 7.

Referring to Fig. 10 there is shown a beating chamber 310 followed by an electrostatic cleaning chamber 311. The web will pass into and through the chamber, starting from its position at 312 over the guide rollers 313 and 314 and then under and over the beaters 315 and 316, respectively. A suction will be applied at 317 and at 318 on the top and bottom of the chamber or compartment 310 which will draw air into the openings 319 and 320, which air will entrain any residual dirt or dust which may be beat out of the web 312.

The web will then pass continuing in a horizontal direction at 321 into the chamber 312 wherein it will be subjected to alternating or pulsating electrostatic charge between the opposite pairs of electrode plates and bars 322 and 323 and 324 and 325.

The suction will also be applied to this static cleaner chamber 311 at 326 at the top of the chamber and at 327 at the bottom of the chamber.

The cleaned web will then pass as indicated at 328 past the guide roller 329 and will be rolled up at 330.

In Fig. 11 the web 340 will pass over the guide rollers 341 into the brushing chamber 342 having the brusher 343 acting on top of the web and 344 acting on the bottom of the web. Suction will be applied at the top of the chamber 342 at 345 and at the bottom of the chamber at 346.

The web will then pass its horizontal path over the guide roller 347 and into the electrostatic cleaning chamber 348 where it is acted upon by the electrostatic charge applied from the opposite plate and bar electrodes 349, 350, 351 and 352. Suction will be applied through the conduits 353 and 354 at the top and bottom of the chamber 348. The cleaned web will then be rolled up as indicated at 355.

In the embodiment of Fig. 12 the beating chamber 360 is positioned above the electrostatic chamber 361 and although the web 362 passes horizontally through both chambers it will pass downwardly between the chambers from the guide roller 363 down to the guide roller 364 as indicated at 365. The upper beaters 365 and the lower beaters 366 and the suction pipes 367 and 368 will exhaust any flock which has been beaten out by the beaters 365 and 366.

jng sleeves 154 and 155 on the removable side plates 156 and 157.

The solid electrodes 112 and 113 will be similarly mounted upon the side plates 156 and 157 by the insulating sleeves 158 and 159. These solid plate electrodes 5 111 and 113 will be covered by the glass plates 160 and 161 which will extend as indicated a short distance between the edges of the plate electrodes 111 and 113.

The exhaust connections as indicated at 162 and 163 will be positioned opposite the middle of the separated 10 electrodes 112 and 113, and they will also be connected to the exhaust main 164 and 165 and 166.

In the arrangement shown the air will be drawn through both the bottom opening 167 and the top opening 168, down and up over the face of the web and also 15 transversely through the web thereof into the exhaust pipes 162 and 163.

This will result in a cleaning of the web and in substantially complete removal of all excess particles, dust and dirt therein, even completely removing that material 20 which may have been pressed further in by the rotary brushes 101 to 105.

Each of the bars 180 of the separated electrode 112, which is typical of the separated electrodes shown in all embodiments, is mounted at the base of its V by the bolt 25 185 upon the vertical bars 152.

This mounting is shown in large scale upon Fig. 9, and it will be noted that the interior of each bar, as indicated at 182, is hollow and that the flat face 183 faces towards the solid electrode and toward the passing web. 30

The corners will be rounded as indicated at 184 so that there will not be any tendency to spark or have an excess concentration of charge at said corners. This will assure a more even distribution of static charge of the flat face 183 of the triangular bar 180. 35

Referring to Fig. 5, there is shown an alternative mechanical removal arrangement. In Fig. 5 the mechanical beater P is provided with a series of square cross section wooden rods 200, 201, 202, 213 and 204, which have sharp edges and which beat the web Q at the points 205, 40 206, 207, 208 and 209. At the same time a very strong exhaust is applied at 210 and 211 on the opposite side walls 212 and 213.

These beaters will act in lieu of or in addition to the brushes of Figs. 1, 2, 3 and 4, to give an initial removal 45 of excess flock and also to treat the web so it is in proper condition to be passed through the static cleaner.

In the arrangement shown in Fig. 7 there is an L-shaped cleaning chamber R having the brush mechanical remover and the static cleaner T. ₅θ

The web U will enter as indicated at 262 and then be subjected to brushing by the brushes 230, 231, 232, 233 and 234.

These brushes are driven by the belt 235 which passes over the idler pulleys 236 and 237. The motor 238 will 55 drive the belt 235.

. The upper chamber S is provided with exhaust connections 239 and 24® upon upper wall 241 and its lower wall 242.

The web after it passes over the pulley 243 will pass βθ downwardly through the static cleaner T.

The static cleaner T has the separated electrodes 244 and 245 which are mounted by means of the insulating sleeves 246 and 247 upon the walls 248 and 249.

The plate electrodes 250 and 251, with their covering 65 glass plates 252 and 253, are also mounted by the insulating sleeves 254 and 255 upon said walls 248 and 249.

The web after being cleaned will pass out through the opening 256 over the pulley 257.

Tlie opposite walls 248 and 249 of the static cleaner 70 section T will be provided with the exhaust connections 258 and 259 opposite the central portion of the separated electrodes 244 and 245.

These exhaust connections 258 and 259, as well as the exhaust connections 239 and 240, will communi- 75

2,980,933

In the lower compartment 361 there will be opposing electrodes 368 and 369 and 370 and 371. This chamber 361 will be exhausted b y the exhaust pipes 372 at the top and 373 at the bottom.

The cleaned web will pass over the guide rollers 374 and 375 and then onto the main collection roller 376.

In the diagrammatic showing of Fig. 13 the hollow triangular electrodes 380 are shown as opposed to a metal plate 381 with the lines of force 382 mushrooming out or diverging outwardly from the bottom portions 383 of the electrodes 380 toward the plate 381.

The arrangement of Fig. 13 has been found to be most effective in assuring a rapid and effective cleaning of the webs or sheets.

In the embodiment of Fig. 14 opposite bar electrodes 384 and 385 are shown with their effective faces 386 and 387 directly aligned with and facing one another so that the lines of 338 will form a more concentrated pattern extending directly transversely in the. space between the faces 386 and 387.

In both the embodiments of Figs. 13 and 14 the fabric 389 and 390 may pass in either direction as indicated by the double arrow's 400 and 401 and the direction, although shown as vertical in Figs. 13 and 14, may be horizontal as shown in Figs. 10 to 12 or oblique at an angle of 30°, 45° or 60° to the horizontal.

In the embodiment of Fig. 14 the hollow triangular bars 402 and 403 are offset so that the lines of force 404 will extend in concentrated manner obliquely across the fabric 405 which may move in either direction 406. This concentrated effect is sometimes most effective with closely adherent small flocked particles. The electrodes may also take other forms such as round, hexagonal, or octagonal, or even square but it has been found desirable to use triangular cross-section electrodes with rounded corners so as to spread the lines of force and prevent any point, edge or corner concentration which might result in sparking.

Less desirably the beating or brushing operations may be combined together with the electrostatic removal and in some instances a final brushing or beating or both may intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.