US3076430A

US3076430A - Device for applying liquid coating to a moving web

Info

Publication number: US3076430A
Application number: US82430A
Authority: US
Inventors: John K Bruce
Original assignee: ALBERT VAN LUIT AND CO
Current assignee: ALBERT VAN LUIT AND CO
Priority date: 1961-01-13
Filing date: 1961-01-13
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05

Description

Feb. 5, 1963 J. K. BRUCE 3, DEVICE FOR APPLYING LIQU'ID comma To A MOVING WEB Filed Jan. 15, 1961 IN VEN TOR. J/w K 590:":

ATTOAP/V'ViZ 3,076,430 V V M DEVICE FOR APPLYING LIQUID COATING TO A MOVING WEB' John K. Bruce, La Verne, Calif, assignor to Albert Van Luit & Co., Los Angeles, Calif., a corporation of California Filed Jan. 13, 1961, Ser. No. 82,430 Claims. cum-413 The invention relates to a device for applying to one side of a moving web a thin uniform coating of low viscosity liquid, particularly the application of such a coating of liquid preservative to the printed side of wallpaper during manufacture thereof.

In manufacturing wallpaper, it is often desired to coat the printed side of the Wallpaper with a transparent liquid preservative. Upon drying of the preservative, it forms .a protective coating which makes the coated side of the wallpaper resistant to liquids and to soiling. These liquid preservatives have a low viscosity, of about that of ordinary water, and may be a Water mixture of the preservative, such as a mixture of twenty-four parts of distilled Water by weight to one part of vinyl acetate by weight. It is desired that the protective coating, after it has dried, have a uniform thickness selected within the range of .0001 to .0002 inch. A coating of this thinness is necessary for economy of manufacture and also to give'a' dull finish, since it has been found that thick coatings of the preservative have an o-bjectionable gloss When dry. Since it has been found that the coating when dry is approximately one-sixth as thick as the coating when wet, it is required that the wet coating of the liquid preservative as applied have a thickness selected within the range of about .0006 to .0012 inch and that the thickness of the wet coat ing be as uniform as possible. The application of such a coating has presented a problem in the wallpaper industry.

The invention solves this problem in the wallpaper industry by providing a coating device which is simple and reliable and which applies to the printed side of wallpaper a coating of a low viscosity liquid preservative of the desired thinness and of substantially uniform thickness. The wallpaper is manufactured in long strips which. are rolled into rolls, and the coating device of the invention applies the preservative coating to the printed side of the strip of Wallpaper as it is continuously pulled through the coating device in a direction parallel to the lengthwise extent of the wallpaper. Such a strip of wallpaper, or of other similar material, is hereafter referred to as a web, and it is to be understood that, although the coating device solves problems in and has particular applicability to the wallpaper industry as stated above, it may be utilized to apply coatings of low viscosity liquids other than preservatives to webs other than wallpaper.

The apparatus of the invention includes, broadly, with respect to a moving web to be coated on one side, a support bar in contact with the uncoated side of the Web mounted in fixed position and extending horizontally the full width of the web in a direction transverse to the direction of movement of the web, a back-up bar mounted adjacent the side of the Web to be coated in vertical. alignment with the support bar which extends horizontally the full width of the web in a direction transverse to the direction of movement of the web, a spreader bar mounted adjacent the coated side of the web and extending horizontally the full width of the web in a direction transverse to the direction of movement of the web which is spaced downweb from the back-up bar in the direction of movement of the web, downweb being used herein in the same sense as downstream as applied to fluid flow. The spreader bar is mounted so that it is "ice free to move vertically and is restrained to movement in such direction only. Sealing means in contact with the side of the web to be coated adjacent each side of the width of the web extend between the back-up bar and the spreader bar and function to block the flow of liquid between such sealing means and the web so that a well for containing the liquid to be coated on the web is defined between the back-up bar, spreader =bar, web and the sealing means. The liquid which is to be applied to the web is disposed in this well. As the web is pulled through the coating device, its surface to be coated forms the bottom of the liquid well, and the liquid is thus thoroughly applied thereto. The liquid in the well causes the spreader bar to, in effect, fioat on the liquid, which thereby defines a gap between the spreader barand the coated side of the web. The vertical extent of this gap determines the thickness of the liquid coating which is applied tothe web. The liquid does not leak out of the well through the gap because of the surface tension of the meniscus of the liquid extending across the gap between'the spreader bar and the web. By maintaining constant the level of the liquid in the well, the floating eifect on the spreader bar is maintained constant, and hence the gap between the spreader bar and the web and the thickness of the coating are also maintained constant. All other factors remaining unchanged, changing the weight of the spreader bar changes the magnitude of the floating etfect on the spreader bar and results in a different vertical extent of gap between the spreader bar and the web fora different thickness of liquid coating. Accordingly, through p-reselection of the weight of the spreader bar, the thickness of the coating of liquid is preselected. v

The invention will be fully understood from a reading of the following description taken in conjunction with the accompanying drawings, in which: I

FIG. 1 is a partially fragmentary plan view of the invention;

FIG. 2 is an end elevational view looking along the line 2-2 in FIG; 1;

FIG. 3 is a sectional elevational view along the line 3-3 in FIG. 1;

FIG. 4 is a sectional elevational view along the line 4-4 in FIG. 1; and

FIG. 5 is an elevational view partially in section along the line 55 in FIG. 1.

Referring to FIG. 1 of the drawings, 10 designates a Web which is to be coated on one side with liquid. The web is a long strip of substantially constant width, is flexible but relatively inextensible, and, as indicated in FIG. 2, has a side 11 which is uncoated, and an obverse side 12 to which a coating ofthe liquid is to be applied; The web is pulled horizontally through the coating device unidirectionally in a direction parallelto its elongate extent. The direction of movement of the web is indicated with the arrows 13 in FIGS. 1 and 2 Vertically extending side support plates 15 and 16 are disposed on each side of the width of the web. The side support plates 15 and 16 are aligned with each other in a direction transverse to the direction of movement of the web. A first support bar 17 extends horizontally between the side support plates 15 and 16 in a direction of extent transverse to the direction of movement of the Web. A second support bar 18, in the same manner as the first support bar, extends horizontally between the side support plates 15 and 16 in a direction of extent transverse to the direction of movement of the web. The second support bar 18 is spaced downweb from the first support bar 17, that is, spaced from the first support bar in the direction which the web 10 moves so that the web moves from the first support bar to the second support bar. The first and second support bars are each fixedly secured at their ends to the side support plates, as by means of bolts, so that they do not rotate or otherwise move, and they are cylindrical members with their uppermost peripheral surface portions tangent to a common horizontal plane and in sliding engagement with the uncoated side 11 of the web. The first and second support members are of rigid construction so that there is negligible deflection in a vertical plane of their span between the side supports 15 and 16.

A back-up bar 21 is disposed on the side 12 of the web to be coated and extends between the side support plates 15 and 16 in a direction of extent transverse to the direction of movement of the web. The back-up bar 20 is cylindrical and its central axis is vertically aligned with the axis of the first support bar 17. The back-up bar is of minimal weight, and for this reason is a tube, as illustrated. Alternatively, the lightweight of the back-up bar 20 may be achieved through the use of lightweight material such as aluminum. At each end of the back-up bar 20, axle stubs 21, 22, respectively, are mounted concentrically on the back-up bar. The axle stubs may be part of a plug secured in conventional manner to the tube portion of the back-up bar. Each side support plate 15 and 16 has a

notch

23, 24, respectively, with vertically extending parallel sides which receive the axle stubs 21, 22, respectively, and function as guides to permit vertical movement of the back-up bar 20 and to restrain its movement to a vertical direction. The vertically extending sides of each

recess

23 and 24 are spaced horizontally from each other an amount sufiicient to give a free working fit between the recess and the axle stub which it receives. A stop pin 25 extends approximately diametrically through the back-up bar 20 and engages the surface of the first support bar 17. The engagement between the stop pin 25 and the first support bar prevents rotation of the backup bar 20. It is apparent that prevention of rotation of the back-up bar 29 may be achieved in other ways obvious to those skilled in the art. Thus, the back-up bar 20 is cylindrical, of minimum weight, is free to move vertically, and is restrained to vertical movement only.

A spreader bar 30 is disposed on the side 12 of the web and extends horizontally between the side support plates in a direction of extent transverse to the direction of movement of the web. The spreader bar is spaced downweb from the back-up bar and is located between the first and second support bars, but slightly closer to the second support bar than to the first support bar, so that when it contacts the side 12. of the web it is supported on the span of the web between the first and second support bars and not on the support bars directly. The spreader bar is cylindrical in shape and is of considerable weight uniformly distributed along its length. It is heavier than the back-up bar 26*. In order that the spreader bar 30 shall have this weight, it is a solid member, as illustrated. The weight of the spreader bar 30 is preselected and is a major factor in determining the thickness of the coating of liquid which is applied to the side 12 of the web, as will be explained below. The weight of the spreader bar may be produced by other means apparent to those skilled in the art, such as making the spreader bar of denser material or uniformly loading it by means of a backing bar or roller or compression spring structure. The spreader bar has at each end a diametrical Vertically extending tang 31, 32, respectively. Each tang 31 and 32 has parallel sides in its vertical extent. Each side support plate has a vertically extending guide 33, 34, respectively. Each guide 33, 34 is comprised of a pair of flanges, as shown, which extend vertically in parallel spaced relation to each other, which are spaced horizontally from each other an amount equal to or slightly greater than the horizontal width of the tangs 31 and 32. and which each receive one of the tangs in vertical sliding engagement. The spreader bar 39 is thus free to move vertically and is restrained to vertical movement only.

Extending between the back-up bar 20 and the spreader bar 34) are a pair of sealing arms 46 and 41. The two sealing arms are identical, and one is positioned adjacent to each elongate edge of the web 10. The distance between the inside surfaces of the sealing arms 4-0 and 41 determines the width of the coating of liquid which is applied to the web. The upweb end of each sealing arm is rotatably connected to the back-up bar and is free to move in a vertical direction only, so that each sealing arm is restrained from horizontal movement but is free to rotate about the back-up bar and to move vertically. This connection of the sealing arms to the back-up bar is effected by means of

recesses

42, 43 in sealing arms 40, 41, respectively, which each have parallel approximately vertically extending sides to receive

axle portions

44 and 45, respectively. The

axle portions

44, 45 are mounted concentrically on the back-up bar 2% in conventional manner such as described above for the axle portions 21 and 22. The horizontal spacing of the approximately vertically extending sides of each recess 42 and is slightly greater than the diameter of the axle portions 54 and 45, rcspec' tively, in order that there is a free working fit between each axle portion and the recess in which it is received for unrestrained vertical movement between the sealing arm and the axle. The diameter of the

axle portions

44 and 45 is less than the diameter of the back-up bar 20 to form a recess in the back-up bar in which the vertical sides of the sealing arms nest. The length of the

axle portions

44 and 45, and hence the length of the recesses formed in the back-up bar, is such that there is a close tolerance working fit between the vertically extending sides of each sealing arm and the vertically extending surfaces of each recess in the back-up bar to effect a liquid seal at the interfaces 35, 36, respectively, between each sealing arm and the back-up bar 26 while still permitting free movement of the back-up bar and sealing arms relative to each other. Each sealing arm rotatably engages the spreader bar 30 by means of engaging portions 46 and 47, respectively, which extend around a portion of the peripheral surface of the spreader bar 36 in sliding engagement therewith. The engaging portions 46 and 47 on the sealing arms do not engage the portion of the peripheral surface of the sealing bar 30 vertically adiacent to the side 12 of the web. The clearance between the sides of each

recess

42 and 43 and the surface of the axle portion which it receives is sufficient to permit the slight movement in a radial direction of the sealing arm produced as it rotates through small angular displacements about the axle with its downweb end moving in a vertical path because rotatably connected to the spreader bar, which is free to move vertically only. As shown in FIG. 5, a plurality of grooves, such as the groove 48, are formed in the surface of the engaging portions 46 and 47 adjacent to the peripheral surface of the spreader bar 30 for the purpose described below. These grooves, such as the groove 43, extend the full extent of the surface of the sealing arm in engagement with the spreader bar. Each sealing arm has a sealing surface 49, 59, respectively, which is planar, slidably engages the surface of the side 12 of the web, and extends between the back-up bar and spreader bar tangentially to their peripheral surfaces. The combined weight of the spreader bar 30 and back-up bar 20 urges together the sealing surfaces 49 and 50 and the side 12 of the web to effect a liquid seal therebetween.

The liquid to be applied to the surface of the side 12 of the web is disposed between the back-up bar 20, spreader bar 30, and sealing arms 40 and 41. These members thus form a well for the liquid. The liquid does not leak past the sealing surfaces 49 and 50, respectively, of the sealing arms by virtue of the above described liquid seal effected between them and the surface of the web. The liquid does not leak between the back-up bar 20 and the web nor between the spreader bar 39 and the web because of the weight of such bars and because of surface tension of the liquid exerted on any meniscus of the liquid extending between the bars and the surface of the web. The grooves 48 in the sealing arms prevent any leakage of the liquid past them due to capillarity. The liquid level in the v. well is maintained at a constant elevation by means of drain tubes 51 and 52 extending through the vertical extent of the sealing arms to the well at a predetermined height above the sealing surfaces 49 and 50 of the sealing arms. conventional drain tube (not'shown), and the well is continuously supplied with the liquid by means of a conventional supply pipe from a pump (not shown) discharging into the well.

When the liquid is disposed in the well, as shown at 53 in FIG. 4, it exerts a floating action on the spreader bar 30, which elevates the surface of the spreader bar 30 from the surface of the side 12 of the web, thereby forming a gap therebetween. The vertical extent of the gap between the surface of the spreader bar 30 and the surface of the web is very small, being on the order of a few ten-thousandths of an inch, and defines the thickness of the coating of the liquid which is applied to the surface of the side 12 of the web. Because of the narrowness of the gap, surface tension on the meniscus of the liquid extending across such gap prevents flow of the liquid through the gap.

The exact thickness of the coating of liquid deposited on the surface of the side 12 of the web depends upon the vertical extent of the above described gap between the spreader bar and the surface of the side 12 of the web. This extent of the gap is dependent upon numerous parameters. For a given set of values of the parameters, the thickness of the coating which is applied is uniform. The most important parameter is the weight of the spreader bar 30. The heavier the spreader bar 30, the thinner will be the coating of liquid applied to the web, the other parameters remaining constant. Other important parameters are the viscosity and density of the liquid 53, the elevation above the Web of the surface of the liquid, the speed of the web, and the surface tension of the particular liquid involved. The thickness of the coating of liquid applied to the web is preselected, and this preselection may be accomplished by the following procedure: All of the above mentioned parameters with the exception of the Weight of the spreader bar are fixed at arbitrary values. Then, with the other parameters remaining constant, a spreader bar 30 which is too light is used in the coating device to give a thicker coating of liquid than is desired. The thickness of such coating is measured, and then, with the other parameters remaining constant, a heavier bar is used in the coating device to obtain a thinner coating. The thickness of this thinner coating is measured, and the differential thickness of the liquid coating produced by the two spreader bars of different weights is computed by subtracting one from the other. This differential thickness of the coating is then used in relation with the differential in weight of the two spreader bars to compute the change in thickness of the coating per unit change in weight of the spreader bar by dividing the former by the latter. This rate is then used to compute the weight of a spreader bar which Will give a coating of the desired thickness, it having been found that within the desired thickness range, namely from .0006 to .0012 inch, there is a direct relationship between the change in the weight of the spreader bar and the resulting change in thickness of the coating of liquid. In following this procedure, the thickness of the coating may be measured by any of various types of conventional means. The weight of the spreader bar is preselected by changing the diameter, of the spreader bar, which necessitates the making of new sealing arms having portions 46 and 47, respectively, which fit the preselected diameter of the spreader bar. Other means apparent to those skilled in the art may be employed to obtain the desired effective weight of the spreader bar, such as a backing bar removably mounted vertically above the spreader bar for vertical movement and engaging the uppermost surface of the spreader bar extending between the sealing arms, which backing bar may be removed and replaced with a backing bar of different weight.

These drain tubes are suitably connected to a amass:

I claim:

1. A coating device for applying a liquid coating to one side of a moving web, comprising a support member in contact with the uncoated side of the web and extending horizontally the width of the web, a back-up bar mounted adjacent the side of the web to be coated in alignment with the support member and extending horizontally the full Width of the Web, a spreader bar mounted adjacent the coated side of the web and extending horizontally the full Width of the Web, said spreader bar being spaced downweb from said back-up bar in the direction of movement of the web and being free to move vertically and restrained to vertical movement only, and sealing means adjacent to each side of the width of the web for blocking liquid flow between the sealing means and the coated side of the Web, said sealing means extending between the back-up bar and the spreader bar, whereby a well for containing a coating liquid is defined between the back-up bar, the spreader bar, the web, and the sealing means.

2. A coating device for applying a liquid coating to one side of a moving web, comprising a fixedly mounted support member in contact with the uncoated side of the web and extending horizontally the full Width of the web transverse to the direction of movement of the web, a back-up bar mounted adjacent the side of the web to be coated in alignment with the support member and extending horizontally the full width of the Web transverse to the direction of movement of the web, a spreader bar of preselected weight mounted adjacent the coated side of the web and extending horizontally the full width of the web transverse to the direction of movement of the web, said spreader bar being spaced downweb from said back-up bar in the direction of movement of the web and being mounted for vertical movement, and sealing means adjacent to each side of the width of the Web and engaging the coated side of the web for blocking liquid flow between the sealing means and the Web, said sealing means extending between the back-up bar and the spreader bar and being movably connected to each, whereby a Well for containing coating liquid is defined between the back-up bar, spreader bar, web, and the sealing means.

3. A coating device for applying a liquid coating to one side of a moving web, comprising a fixedly mounted support member in contact with the uncoated side of the web and extending horizontally the full width of the web transverse to the direction of movement of the web, a backup bar mounted adjacent the side of the web to be coated in alignment with the support member and extending horizontally the full width of the Web transverse to the direction of movement of the web, a spreader bar of preselected weight mounted adjacent the coated side of the web and extending horizontally the full width of the web transverse to the direction of movement of the web, said spreader bar being spaced downweb from said back-up bar in the direction of movement of the web and being mounted for vertical movement, and sealing means adjacent to each side of the width of the web and engaging the coated side of the web for blocking liquid flow between the sealing means and the web, said sealing means extending between the back-up bar and the spreader bar and being movably connected to each, whereby a well for containing coating liquid is defined between the back-up bar, spreader bar, web, and the sealing means, said spreader bar having its surface adjacent to the web curved about an axis extending transverse to the direction of movement of the web.

4. A coating device for applying a liquid coating to one side of a moving web, comprising a fixedly mounted support bar in contact with the uncoated side of the web and extending horizontally the full Width of the web transverse to the direction of movement of the web,

sprenso a back-up bar mounted adjacent the side of the web to be coated in alignment with the support bar and extending horizontally the full width of the Web transverse to the direction of movement of the web, said back-up bur being mounted for vertical movement, a spreader bar of preselected weight mounted adjacent the coated side of the web and extending horizontally the full width of the web transverse to the direction of movement of the web, said spreader bar being spaced downweb from said backup bar in the direction of movement of the web and being mounted for vertical movement, and sealing means adjacent to each side of the width of the web and engaging the coated side of the web for blocking liquid flow between the sealing means and the web, said sealing means extending between the bacloup bar and the spreader bar and being movably connected to each, whereby a well for containing coating liquid is defined between the back-up bar, spreader bar, web, and the sealing means said spreader bar and said back-up bar each having their surfaces adjacent to the web curved about an axis transverse to the direction of movement of the web.

5. A coating device for applying a liquid coating to one side of a moving web, comprising a pair of fixedly mounted support bars in contact with the uncoated side of the web and extending horizontally the full width of the web transverse to the direction of movement of the web, said support bars being spaced from each otheer in the direction of movement of the web, a back-up bar mounted adjacent the side of the web to be coated in vertical alignment with the upweb support bar and extending horizontally the full width of the web transverse to the direction of movement of the web, said back-up bar being mounted for vertical movement, a spreader bar of preselected weight mounted adjacent the coated side of the web intermediate the two support bars and extending horizontally the full Width of the Web transverse to the direction of movement of the Web, said spreader bar being spaced downweb from said back-up bar in the direction of movement of the web and being mounted for vertical movement, and sealing means adjacent to each side of the width of the web and engaging the coated side of the web for blocking liquid flow between the sealing means and the web, said sealing means extending between the back-up bar and the spreader bar and being movably connected to each, whereby a well for containing coating liquid is defined between the back-up bar, spreader bar, web, and the sealing means, said spreader bar and said buck-up bar each having their surfaces adjacent to the web curved about an axis transverse to the direction of movement of the web.

6. A coating device for applying a liquid coating to one side of a moving web, side supports on each side of the web in aligned relation to each other, a first support bar on the uncoated side of the web engaging the uncoated side of the web and extending horizontally between the side supports transverse to the direction of movement of the web, a second support bar on the uncoated side of the web engaging the uncoated side of the web, said second support bar being spaced from the first support bar downweb in the direction of movement of the web and extending horizontally between the side supports transverse to the direction of movement of the web, said first and second support bars having the portions of their surfaces engaging the web aligned horizontally, a back-up bar disposed on the side of the web to be coated in vertical alignment with the first support bar and extending horizontally between the side supports transverse to the direction of movement of the web, a spreader bar of preselected weight disposed on the side of the web to be coated intermediate the first and second support bars in spaced relation from the back-up bar downweb in the direction of movement of the web and extending between the side supports transverse to the direction of movement of the web, said spreader bar being mounted on the side supports for vertical movemerit, and a vertically extending sealing arm extending between the back-up bar and the spreader bar at each side of the width of the web and movably connected to the bacloup bar and to the spreader bar, each said sealing arm having a sealing surface extending between the backup bar and the spreader bar substantially coplanar with the peripheral surfaces of the backup and spreader bars, said sealing surfaces being in sliding engagement with the surface of the portion of the side of the web to be coated extending between the back-up bar and the spreader bar to block flow past the engagement of the web and the sealing surfaces of a coating liquid disposed between the back-up bar, the spreader bar, and the sealing arms.

7. A coating device for applying a liquid coating to one side of a moving web, side supports on each side of the web in aligned relation to each other, a first support bar on the uncoated side of the web slidably engaging the uncoated side of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, a second support bar on the uncoated side of the web slidably engaging the uncoated side of the web, said second support bar being spaced from the first support bar downweb in the direction of movement of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, said first and second support bars having the portions of their surfaces engaging the web aligned horizontally, a cylindrical backup bar disposed on the side of the web to be coated in vertical alignment with the first support bar and extending horizontally between the side supports transverse to the direction of movement of the web, said back-up bar being mounted on the side supports for vertical movement, a cylindrical spreader bar of preselected weight disposed on the side of the web to be coated intermediate the first and second support bars in spaced relation from the back-up bar downweb in the direction of movement of the web and extending between the side supports transverse to the direction of movement of the web, said spreader bar being mounted on the side supports for vertical movement, and a vertically extending sealing arm extending between the back-up bar and the speader bar at each side of the width of the web and movably connected to the back-up bar and to the spreader bar, each said sealing arm having a planar face extending between the back-up bar and the spreader bar substantially tangentially to their peripheral surfaces in sliding engagement with the surface of the portion of the side of the web to be coated extending between the back-up bar and the spreader bar'to block liquid flow past the engagement of the web and the faces on the sealing arms of a coating liquid disposed between the back-up bar, spreader bar, and the sealing arms.

8. A coating device for applying a liquid coating to one side of a web movable in the direction of its elongate extent, vertically extending side supports on each side of the web in aligned relation to each other, a first cylindrical support bar on the uncoated side of the web slidably engaging the uncoated side of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, a second cylindrical support bar on the uncoated side of the web slidably engaging the uncoated side of the web, said second support bar being spaced from the first support bar downweb in the direction of movement of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, said first and second support bars having the portions of their peripheral surfaces engaging the web aligned horizontally, a cylindrical back-up bar disposed on the side of the web to be coated in vertical alignment with the first support bar and extending horizontally between the side supports transverse to the direction of movement of the web, said back-up bar being slidably mounted on the side supports for vertical movement only, a cylindrical speader bar of preselected weight disposed on the side of the \web to be coated intermediate the first and second support bars in spaced relation from the back-up bar downweb in the direction of movement of the web and extending between the side supports transverse to the directionof movement of the web, said spreader bar being slidably mounted on the side supports for vertical movement only, a vertically extending sealing arm extending between the back-up bar and the speader bar at each side of the width of the web and rotatably connected to the back-up bar and to the speader bar, each said sealing farm having a planar face extending between the back-up; bar and the spreader bar substantially tangentially to their peripheral surfaces in sliding engagement with the surface of the portion of the side of the web to be coated extending between the back-up bar and the spreader bar to block liquid flow past the engagement of the web and the faces on the sealing arms of a coating liquid disposed between the back-up bar, spreader bar, and. the sealing arms, said sealing arms being rotatably connected to the spreader bar by means of a circular portion extending partially around the peripheral surface of the spreader bar in slidable bearing engagement therewith and said sealing arms being rotatably connected to .the back-up bar by means of a vertical notch in the sealing arm permitting both rotational and vertical movement of the sealing arm relative to the back-up bar.

9. A coating device for applying liquid coating to one side of aweb movable in the direction of its elongate extent, vertically extending side supports on each side of the web in aligned relation to each other, a first cylindrical support bar on the uncoated side of the web slidably engaging the uncoated side of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, a second cylindrical support bar on the uncoated side of the web slidably engaging the uncoated side of the web, said second support bar being spaced from the first support bar downweb in the direction of movement of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, said first and second support bars having the portions of their peripheral surfaces engaging the web aligned horizontally, a cylindrical back-up bar disposed on the side of the web to be coated in vertical alignment with the first support bar and extending horizontally between the side supports transverse to the direction of movement of the web, said back-up bar being slidably mounted on the side supports for vertical movement only, a cylindrical spreader bar of preselected weight disposed on the side of the web to be coated intermediate the first and second support bars in spaced relation from the back-up bar downweb in the direction of movement of the web and extending between the side supports transverse to the direction of movement of the web, said spreader bar being slidably mounted on the side supports for vertical movement only, a vertically extending sealing arm extending between the back-up bar and the spreader bar at each side of the width of the web and rotatably connected to the back-up bar and to the spreader bar, each said sealing arm having a planar face extending between the back-up bar and the spreader bar substantially tangentially to their peripheral surfaces in sliding engagement with the surface of the portion of the side of the web to be coated extending between the back-up bar and the spreader bar to block liquid flow past the engagement of the web and the faces of the sealing arms of a coating liquid disposed between the back-up bar, spreader bar, and the sealing arms, said sealing arms being rotatably connected to the spreader bar by means of a circular portion extending partially around the peripheral surface of the spreader bar in slidable bearing engagement therewith and having a plurality of grooves adjacent to the surface of the spreader bar in its portion so surrounding the engaged surface of the spreader bar, said sealing arms being rotatably connected to the back-up bar by means of a vertical notch in the sealing arm permitting both rotational and vertical movement of the sealing arm relative to the back-up bar, and an aperture in the vertical extent of a sealing arm spaced vertically from the web to limit the level of a coating liquid disposed between the back-up bar, spreader bar, and sealing arms.

10. A coating device for applying a liquid coating to one side of a web movable in the direction of its elongate extent, vertically extending side supports on each side of the web in aligned relation to each other, a first cylindrical support bar on the uncoated side of the web slidably engaging the uncoated side of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, a second cylindrical support bar on the uncoated side of the web slidably engaging the uncoated side of the web, said second support bar being spaced from the first support bar downweb in the direction of movement of the web and extending horizontally between the side supports transverse to the direction of movement of the web and fixedly secured to the side supports, said first and second support bars having the portions of their peripheral surfaces engaging the web aligned horizontally, a cylindrical back-up bar disposed on the side of the web to be coated in vertical alignment with the first support bar and extending horizontally between the side supports transverse to the direction of movement of the web, vertically extending guides on each side support slidably receiving each end of the back-up bar for vertical movement only of the back-up bar, a cylindrical spreader bar of preselected weight disposed on the side of the web to be coated intermediate the first and second support bars in spaced relation from the back-up bar downweb in the direction of movement of the web and extending between the side supports transverse to the direction of movement of the Web, vertically extending guides on each side support slidably receiving each end of the spreader bar for vertical movement only of the spreader bar, a vertically extending sealing arm extending be tween the back-up bar and the spreader bar adjacent each side of the width of the web and rotatably connected to the back-up bar and to the spreader bar, each said sealing arm having a planar face extending between the back-up bar and the spreader bar substantially tangentially to their peripheral surfaces in sliding engagement with the surface of the portion of the side of the web to be coated extending between the back-up bar and the spreader bar to block liquid flow past the engagement of the web and the faces on the sealing arms of a coating liquid disposed between the back-up bar, spreader bar, and the sealing arms, said sealing arms being rotatably connected to the spreader bar by means of a circular portion extending partially around the peripheral surface of the spreader bar in slidable bearing engagement therewith and having a plurality of grooves adjacent to the surface of the spreader bar in its portion so surrounding the engaged surface of the spreader bar, said sealing arms being rotatably connected to the back-up bar by means of a vertical notch in the sealing arm permitting both rotational and vertical movement of the sealing arm relative to the back-up bar, and an aperture in the vertical extent of a sealing arm spaced vertically from the web to limit the level of a coating liquid disposed between the back-up bar, spreader bar, and sealing arms.

References Cited in the file of this patent UNITED STATES PATENTS