US3331351A - Paper coating apparatus - Google Patents

Description

July 18, 1967 c. E. WE RNER 3,331,351

PAPER COATING APPARATUS Filed Oct. 15, 1964 2 Sheets-Sheet 1 PRIOR ART /0 INVENTOR.

CHARLES E WERNER July 18, 1967 c. E. WERNER 3,331,351

I PAPER COATING APPARATUS Filed Oct. 15, 1964 2 Sheets-Sheet 2 INVENTOR.

CHARLES E WERNER United States Patent 3,331,351 PAPER COATING APPARATUS Charles E. Werner, Chillicothe, Ohio, assignor to The Mead Corporation, Dayton, Ohio, a corporation of Ohio Filed Oct. 15, 1964, Ser. No. 404,119 6 Claims. (Cl. 118-70) pass a web of paper supported by a rotating roll through a pool of fluent coating material and thereafter past a trailing blade bearing on the web of material to limit the thickness of and smooth the coating applied to the web. Heretofore, various attempts have been made to provide end dams for paper coating machines but all such prior art devices have suffered from one or more serious disadvantages which has in some respect limited their utility. Such prior art end dams have usually required frictional contact between the edge of the end dam and the rotating surface or surfaces. Such structural arrangements require that the contacting surface of the end dam which engages the rotating surface have precisely the same radius of curvature as the rotating surface because, if this requirement is not met, leakage of the fluent coating material will result. Furthermore, if the contacting surface of the end dam is of a lesser radius than the rotating surface, one or more points of relatively high bearing pressure will result so that the area of the rotating surface in contact with the end dam is subjected to abnormal wear which results in a groove being formed on the rotating surface.

Since the conventional rotating surfaces are rolls having a'resilieut outer cover which is ground to maintain desired smoothness, relatively frequent changes occur in the radius of the roll so that curvature of the edge of the end dam, following a period of operation, no longer conforms'to the curvature of the roll, particularly after the roll has been reground a number of times. Furthermore, attempts have been made to minimize the lack of good fit between the edge of the end dam and the roll surface by placing the end dams so that they engage the edge of the web which is in turn supported by the roll. Even so, the roll surface is deformed and grooved by the pressure of the end dam, and such grooved rolls must be reground to a smooth surface before a wider web can be coated. Additionally, the prior art arrangements have resulted indifiiculty in avoiding scoring or otherwise marking or damaging of the coated sheet.

Accordingly, a principal object of the present invention is to provide improved means for overcoming the abovenoted deficiencies and difliculties.

It is a further object of the invention to provide an end dam sealing structure that will provide maximum flexibility in the width of the paper web to be coated.

Still another object of the invention is to provide an arrangement whereby the end dams are mounted independently of the coating head assembly with resilient backed sealing means to permit blade adjustment without requiring a concurrent end dam adjustment.

A further object is in the provision of an improved arrangement for achieving a positive seal between the coating head and the roll in sucha manner and at such a location that destructive wear of the roll and the sealing elements is minimized.

Still another object of the invention is in the provision of an improved means for containing the color in the puddle of a puddle type blade coater which employs only elements that are mechanically simple and easy to manufacture and install, and at the same time, avoids operational difficulties which may arise from the tendency for dried color to build up on the face of the roll and in the sealing apertures.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a diagrammatic plan view of an end dam illustrating prior art devices;

FIGURE 2 is a diagrammatic pli-an view illustrating one L embodiment of the end dam of the present invention;

FIGURE 3 is an enlarged plan view partly broken away of the embodiment of FIGURE 2;

FIGURE 4 is an enlarged side elevation partly broken away of the embodiment of FIGURE 2; and,

FIGURE 5 is an enlarged plan view partly broken away illustrating an alternative embodiment of the invention.

Referring now to the drawings, in FIGURE 1, a web 10 of paper, paperboard or the like, is led downwardly over a roll 11 which has a resilient cover 12. A coating head 13 carrying a blade 14 is mounted so that the blade tip engages the surface of the web 10.

End dams 16 16, of the type used prior to this inventron, are rigidly mounted on the coater head 13 andshaped to conform to the curvature of the resilient surface 12 of roll 11. End dams 16-16 are positioned to engage the edges of web 10, and are intended to retain the fluent coating material in the trough formed by the web on the backing roll, the blade and the coating head.

One embodiment of the improved end dam of this invention is ilustrated in FIGURE 2. The general features of Web 10 supported by resilient member 12, backing roll 11 and moving past the tip of blade 14 which is mounted on coating head 13 are the same as illustrated in FIGURE 1. Again referring to FIGURES 2 and 3, the end dams 17 of the present invention are mounted on brackets 15 to a part of the machine frame (not shown) and are positioned adjacent the ends of roll 11. The front edge of the end dams is curved to generally conform to the curvature of roll surface 12, as is best illustrated in FIGURE 4. The positioning of the end dam 17 at the ends of roll 11 permit the operation of the coater with any desired width of web, up to the limit of the spacing between the end dams, without requiring a change in the location of the end dams. Contrary to expectations, it has been found that no new problems are introduced by contact of the pool of fluent coating material with the resilient surface 12 of roll 11 in areas not covered by Web 10. The fluent coating material acts as a lubricant to minimize wear of the roll surface by the blade tip and leakage of coating material at the edges of the web is prevented by a small line or band of coating material which dries on the face of the roll. If this dried coating material accumulates to an objectionable amount, a small water spray directed onto the dried coating on the roll surface will control or eliminate excessive accumulation of such material. The absence of sealing surfaces bearing on the edges of the paper web greatly reduces the incidence of web brakes causd by wrinkles and cracked or torn edges, thus provid ing significantly more eflicient operation of the coating machine.

As noted heretofore, it is desirable to provide a positive seal between the coating head and the roll and at the same time to avoid undue pressure against the resilient cover 12 which results in excessive wear and grooving of the resilient cover. In accordance with the present invention, this is achieved by causing a resilient member to seal against a seal plate mounted closely adjacent the opposite ends of roll 11 and with pressure exerted by the resilient sealing material against the resilient cover 12 confined to an extremely small area at each end of roll 11 so that no appreciable wear of the usable surface of resilient cover 12 is encountered.

Each of the end dams 17 comprises a support member 18, resilient sealing material 19, and a seal plate member 20. One of these end dams will now be described in greater detail and it is to be understood that such description applies equally to the other darn which is disposed at the opposite end of roll 11.

Support member 18 is detachably connected to coating head 13 by any known means. Conveniently, threaded fastening means may be employed to effect the connection between coating head 13 and support member 18. Support member 18 extends outwardly from coating head 13 in a direction generally toward the outer resilient surface 12 of roll 11 and terminates somewhat short thereof. A illustrated in FIGURE 2, one side of face 24 of support member 18 is substantially aligned with and lies generally in a plane which includes the end face of roll 11.

A seal plate member 20 is adjustably connected to bracket which bracket is connected to a portion of the machine frame (not shown). The means employed for effecting such connection between sealing plate and bracket 15 will be described in greater detail as the description proceeds. For present purposes, it will be sufficient to state that the adjustable connecting means permits the placing and maintaining of seal plate member 20 in a desired location relative to roll 11 and support member 18.

Seal plate member 20 is a plate like member having spaced apart opposed faces 21, 22 which are substantially parallel. Interposed between faces 21, 22 is a face portion 23 that is also substantially parallel to faces 21, 22. In the drawing, face 1 extends to the left from the right hand end of seal plate member 20 while face portion 23 extends to the right from the left hand portion of seal plate member 20. Face 21 and face portion 23 are each shorter in length than face 22 and are connected together by a wall 24 that is angularly disposed relative to the substantially parallel plane surfaces of face 21 and face portion 23. When installed for operation, sealing plate member 20 is maintained by bracket 15 in such position that faces 21, 22 and face portion 23 are substantially parallel With the end face of roll 11 with face 21 positioned closely adjacent the end face ofroll 11 with sufficient clearance space so as to avoid mechanical interference with these elements during rotation of roll 11. It will be appreciated that when in said position, face 21 of sealing plate 20 lies within or is substantially within and closely spaced from and parallel to a plane containing the outer face 25 of support member 18. Hence, face portion 23 of seal plate member 20 is spaced apart from and substantially parallel to the outer face 25 of support member 18. Disposed in the space between face member 23 and the outer face 25 is resilient sealing material 19 having a front edge portion that is curved to conform generally with the curvature of resilient surface 12. Sealing material 19 is secured in any convenient manner to support member 18. For example, threaded fastening means 26 may be employed to connect the sealing material 19 to support member 18. interposed between the back edge of member 18 and the coating head 13 is resilient sealing material 27 for effecting a liquid tight seal between the member 18 of end dam 17 and coating head 13. Material 27 may be rubber sheeting, sponge rubber or the like. Accordingly, relatively small movement of coating head 13 and blade 14 toward roll 11 to compensate for wear of the blade tip does not require repositioning or readjustment of the end dams.

It is to be noted that when coating head 13 is in operating position, the forward edge portion of the resilient sealing material 19 extends radially inward along the end face of roll 11 byond the outer resilient surface 12. Attention is also directed to the fact that as the coating head 13 is advanced toward roll 11 into operating position the forward edge portion of material 19 begins to engage the angularly disposed portion 24 of seal plate member 20 thus producing a force in a direction parallel to the axis of rotation of roll 11 that tends to press the resilient sealing material 19 between the outermost portion of the end face of roll 11 and faces 23 and 24 of seal plate member 20 thus sealing and confining the fluent material which is confined in the space between coating head 13, outer surface 12 of roll 11 and also between end dams 17-17 which are disposed at opposite ends of the roll. Thus, it will be seen that any sealing pressure exerted upon roll 11 is exerted in a direction parallel to rather than normal to the axis of rotation thereof and is applied to the end faces of the roll and not against the resilient cover surface 12 upon which the web 10 is carried.

In the alternative embodiment of the end dams 17-17 illustrated in FIGURE 5, the same structural elements are employed as in the case of the embodiment of FIG- URE 3 but the relative positions of the elements are modified somewhat. In the alternative embodiment, the forward edge portion of resilient sealing material 19, as well as the inclined face 24 of sealing plate member 20, are moved relatively to the left from the position illustrated in FIGURE 3 so that sealing material 19 is urged by inclined face 24 into engagement with not only the end face of roll 11 but a portion of the sealing material also contacts the outed surface of resilient cover 12. Such contact of the outer surface 12 by the sealing material is confined to a very small area closely adjacent the corner formed by the intersection of the end face of roll 11 and the resilient cover 12 so that if any grooving or other destructive effect of the pressure of the sealing material on the resilient cover does result, such grooving is confined to a very small area at the opposite extremities of the cover and such effects are confined to extremely small areas which are remote from web 10 and do not fall within the usable surface of resilient cover 12.

Based on information and operating experience presently available, the embodiment illustrated in FIGURE 3 generally is considered the preferred embodiment but experience also has shown that the alternative embodiment illustrated in FIGURE 5 not only provides a satisfactory seal but in certain instances the alternative embodiment may be more desirably employed than the embodiment of FIGURE 3.

Irrespective of whether it is desired to employ the embodiment of FIGURE 3 or that of FIGURE 5, a plurality of jack screws 28, 29 are employed to adjustably connect the sealing plate member 20 to bracket 15. The jack screws 23, 29 provide sufficient flexibility to permit plate member 20 to be positioned closely adjacent the end face of roll 11 and at the same time permit whatever adjustment may be necessary in order to assure the desired degree of parallelism between the end face of roll 11 and faces 21, 22 and 23.

When prior art end dams have been used in connection with a puddle type blade coater for containing the color in the puddle, operating difficulties have been quite severe due to the tendency for dried coating color to build up on the face of the roll and in the sealing passageways thus interfering with the collecting system and causing color to be thrown from the face of the roll. In accordance with the present invention, this difiiculty is avoided because the seal plate is positioned in close proximity to the end face of the roll. Also, a conduit 30 provides a small supply of water to the aperture between face 21 of seal plate member 20 and the end face of roll 11 so that the end of the roll remains clean and color throw-off is avoided.

Thus, it will be seen that the invention provides an effective end dam seal which provides maximum flexibility and operation with reference to the width of web to be handled, employs structural elements which are mechanically simple, does not require precise dimensions of the sealing material, and provides effective sealing without destructive action on the usable outer surface of the roll.

While particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the invention, and it is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the invention.

What is claimed is:

1. In an apparatus providing a reservoir for supplying fluent coating material to a roll-carried sheet, the combination comprising a coating roll provided with a resilient surface; a coating head; and end dams shaped to conform to the curvature of the said resilient surface of said roll and positioned at each end of said rolls to form a reservoir with said roll, each of said end dams comprising a support member detachably connected to said coating head and extending outwardly therefrom, a seal plate member provided with a chamfered surface and mounted closely to the ends of said roll, and a resilient sealing member, said resilient sealing member being secured to said support member and positioned between said chamfered sealing plate and said roll in such a manner that the leading edge of said resilient sealing member is urged by said chamfered surface into engagement with said roll end and thereby sealing said reservoir.

2.. The combination of claim 1 including means for urging the plate member toward the end faces of said roll.

3. The combination of claim 2 wherein said urging means includes a member spaced from and disposed in close proximity with the end face of said roll, and including means including conduit means for supplying a solvent to the space between the end face of said roll and said closely spaced member.

4. The combination of claim 1 wherein said sealing means is urged partly in a radial direction against the cylindrical outer surface of said roll and partly in an axial direction against the end face of said roll.

5. In an apparatus providing a reservoir for supplying fluent coating material to a roll-carried sheet comprising a coating roll provided with a resilient surface, a coating head, end dams shaped to conform to the curvature of the resilient surface of said roll and positioned at each end of said roll to form a reservoir with said roll, the improvement which comprises providing for each of said end dams a support member detachably connected to the said coating head and extending outwardly therefrom, a seal plate member provided with a chamfered surface and mounted closely to the ends of said roll, and a resilient sealing member secured to said support member and positioned between said chamfered sealing plate and said roll in such a manner that the leading edge of said resilient sealing member is urged by said chamfered surface into engagement with said roll and thereby sealing said reservon.

6. The combination of claim 5 wherein said sealing means is urged partly in a radial direction against the cylindrical outer surface of said roll and partly in an axial direction against the end face of said roll.

References Cited UNITED STATES PATENTS 2,105,981 1/1938 Massey et a1. 118203 X 2,281,588 5/1942 Magnus 118-259 X 2,918,899 12/1959 Munton et a1. 118-413 3,097,968 7/ 1963 Schaefer 118259 3,169,082 2/ 1965 Krikorian 118413 3,179,536 4/1965 Martinek 118-40 7 X CHARLES A. WILLMUTH, Primary Examiner. J. P. MCINTOSH. Assistant Examiner.

Claims (1)

1. IN AN APPARATUS PROVIDING A RESERVIOR FOR SUPPLYING FLUENT COATING MATERIAL TO A ROLL-CARRIED SHEET, THE COMBINATION COMPRISING A COATING ROLL PROVIDED WITH A RESILIENT SURFACE; A COATING HEAD; AND END DAMS SHAPED TO CONFORM TO THE CURVATURE OF THE SAID RESILIENT SURFACE OF SAID ROLL AND POSITIONED AT EACH END OF SAID ROLLS TO FORM A RESERVOIR WITH SAID ROLL, EACH OF SAID END DAMS COMPRISING A SUPPORT MEMBER DETACHABLY CONNECTED TO SAID COATING HEAD AND EXTENDING OUTWARDLY THEREFROM, A SEAL PLATE MEMBER PROVIDED WITH A CHAMFERED SURFACE AND MOUNTED CLOSELY TO THE ENDS OF SAID ROLL, AND A RESILIENT SEALING MEMBER, SAID RESILIENT SEALING MEMBER BEING SECURED TO SAID SUPPORT MEMBER AND POSITIONED BETWEEN SAID CHAMFERED SEALING PLATE AND SAID ROLL IN SUCH A MANNER THAT THE LEADING EDGE OF SAID RESILIENT SEALING MEMBER IS URGED BY SAID CHAMFERED SURFACE INTO ENGAGEMENT WITH SAID ROLL END AND THEREBY SEALING SAID RESERVOIR.

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