US1957817A - Process and apparatus for making paper - Google Patents

Description

May 8, 1934.,

G. G. BRIGHT PROCESS AND APPARATUS FOR MAKING PAPERv Filed Feb. 27, l953 4 Sheets-Sheet 1 May 8, 1934.

C. G. BRKBHT PROCESS AND APPARATUS FOR MAKING PAPER Filed Feb. 27, 1953 4 Sheets-Shee:t 2

5 CiuzZ C D hi" A 7'85 T1 2 May 1934- k c. ca. BRIGHT 1,957,817

PROCESS AND APPARATUS FbR MAKING PAPER Filed Feb, 27, 1933 4 Sheets-Sheet 3 ll u fizz/Quiz" 3 @150 WIQSM+M%I Mays, 1934.

C. G. BRIGHT PEOCESS AND APPARA'I'US F'QR MAKING PAPER 4 Sfieets-Sheet 4 Filed Feb 1 fizz/612i?" C'iiczrzes Patented May 8,1934

PATENT OFFICE PROCESS AND APPARATUS FOR MAKING PAPER Charles G. Bright, Appleton, Wla, assignor to Paper Patents Company, Neenah, Wis., a corporation of Wisconsin Application February 27, 1933, Serial No. 658,731 8 Claims. ((192- 40) This invention relates to the art of paper making and has reference more particularly to the manufacture of papers coated on the machine.

One of the objects of the present invention is to provide an improved organized method of and apparatus for making a paper having its outer surface treated with a filler or color, and to provide an arrangement whereby a coating of such color of any desired thickness may be applied to and securely anchored on the outer surface of the paper.

According to the present process the coating or color, which may consist chiefly of an insoluble inorganic mineral suc h'as china clay, satin white,

chalk or other suitable mineral mixed with a suitable binder, such as starch or casein, or both, is applied to the paper web during the manufacture of the paper; that is, on the paper machine, preferably after the paper web has passed over part i of the driers; and the application is made in two stages. First, by the aid of pressurerolls involving the use of considerable pressure a thin layer of the color is forced into the surface stratum of the web as a filler while the latter is v 5 still somewhat damp, so that excess color is removed and the remainder is thoroughly incorporated with and anchored to the fibers in such surface stratum; and then a perhaps thicker layer preferably of the same material in the nature of 0 a coating is uniformly and evenly applied to the same surface and dried thereon. To hasten drying and prevent the coating from sticking to the surface of subsequent drying drums or rolls, it is preferably subjected, immediately after its application, to the bathing action of a stream of hot air, preferably while traveling over the first drying drum beyond the point of applicationof the coating.

' In order that the novel principle of the invention, the manner in which the same is carried out, and the practical advantages flowing therefrom may be readily understood by persons skilled in the art, I have, in the accompanying drawings, illustrated somewhat diagrammatically a machine for treating a paper web embodying certain novel'structural features and operating in accordance with the improved process; and referring thereto:-

Fig. 1 is a diagrammatic side elevation of the machine.

Fig. 2 is a side elevation, partly in vertical section of an apparatus that may be used for first filling the surface of the web, and then applying tothe filled surface a uniform coating of the desired thickness.

Fig. 3 is an elevation, partly in vertical section, of an apparatus for applying a stream of heated air to the coating as the web passes over the first drying drum beyond the point of application of the coating. 1

Fig. 4 is a vertical section of a portion of the drying apparatus, taken on the line 4-4 of Fig. 3.

Fig. 5 is a. detail sectional view taken on the line 5-5 of Fig. 3.

Fig. 6 is a sectional detail of a part of the throwout mechanism, taken on the line 6-6 of Fig. 2.

Referring to the drawings, the paper web W as it comes from the wet end of the paper machine, is first passed through a series of drying cylinders 10 and 11 illustrated at the left of Fig. 1, preferably in association with upper and lower felts 12 and 13, respectively, that press the wet web into intimate contact with the cylinders. From the last cylinder 10 the partly dried web passes over driven guide rolls 14 into the nip of a pair of pressure rolls 15 and 16, mounted on a frame.19, by which one side of the web is treated with a.filler that is forced under considerable pressure, into the surface, stratum j of the web. The lower roll 16 dips in a pan 1'7 of the filling material, picking up the latter and transferring it directly to the surface of the web. The structural details of these pressure rolls are not herein fully illustrated, as such details form no part of .the present'invention; but they preferably. conform substantially to the pressure rolls fully described in the application of Rudolph C. Germanson and Frederick Kranhold for Paper and process and apparatus for making the same, Serial 647,864 filed December 19, 1932.

Referring now more particularly to Fig. 2, the filled web passes from the pressure rolls 15, 16, upwardly over a suitably mounted revolving abutment roll 18. Associated with the roll 18 is an apparatus for applying a coating of uniform thickness to the filled surface of the web, this apparatus including means by which the coating may be uniformly and evenly laid, and its thickness varied as desired.

Side frame members 19' mounted on a machine base 20 are formed on their upper sides with slideways 21 for a pair of horizontal slides 22. Said slides 22 carry pillow blocks 23, journaled in and between which is an applicator roll 24 that dips into a suitably supported pan 25 containing the coating mix. Associated with the applicator roll 24 is a doctor roll 26 that is similarly journaled in a pair of pillow blocks 2'7 that are slidably mounted on the slide 22. This doctor roll 26 is also shown as dipping into the pan 25 and 110 provided with a scraper or doctor blade 28 to force back the coating material picked up thereby, although in practice it is not essential that the doctor ifollsy26 dip into the coating material.

The'rolls 18, 24,: and 26 turn in the directions indicated by the arrows in Fig. 2, and the function of the doctor roll 26 in its relation to the applicator roll 24 is to determine the thickness of the layer of coating material transferred by the roll 24 to the surface of the web. For this purpose, between the pillow blocks 23 and 27 on each side there is interposed an adjustable spacing device comprising a threaded stud 29 secured in one of the pillow blocks, for example the pillow block 27 as shown, and equipped with an adjusting nut 30 that bears against one end of a thrust spring 31 encircling the stud 29 and abutting against the other pillow block 23. This device normally tends to separate the rolls 24 and 26. Cooperating with each of the pillow blocks 27 is a micrometer adjustment comprising a screw 32 mounted in a vertical lug 33 on the slide 22, at its inner end bearing against the block 27 and at its outer end'equipped with a micrometer head 34 for turning the same. Manifestly, this device acts in opposition to the spring 31 to accurately maintain the spacing of the rolls 24 and 26 in any set position. If a thin coating is desired, the

screw 32 is adjusted inwardly; if a thicker coat ing is desired, the screw is adjusted outwardly.

In association with the above described mechanism, there is also provided a simple manually operable means by which the amount of spacing between the applicator roll 24 and the web may be adjusted as desired and maintained in adjusted position, and .in association therewith a quick throw-out device by which the applicator roll 24 may be fully backed off from the web.

Describing these last-named features, 35 designates a screw threaded rod mounted in a pair of lugs 36 on the frame 19, said rod bearing at its inner end against the inner end of the slide 22- and at its outer end equipped with a micrometer head 37. By means of this rod 35 the applicator roll 24 may be adjusted away from the abutment roll 18. Slide 22 is held continuously in contact with the inner end of the rod 35 by mechanism shown at the left of Fig. 2, and comprising a screw threaded rod 38 secured at its inner end in the outer end of the slide 22 and having on its outer end a head 39. A block 40 slidably mounted on the frame 19 and apertured for the passage of the rod 38 is pressed against the head 39 by a thrust spring 41 confined between the innerside of the block 40 and a nut 42 on the rod 38. On

the block 40 is a lateral pin 43 carrying a square block 44 slidably fitted in a slot 45' in the upper end of a lever 45 that is pivoted at 65 on the frame 19 and has itslower end pivoted at 66 to a link 67 formed at its other end with an eccentric strap 68 encircling. an eccentric 69. This eccentric is fast on a short shaft '70 (Fig. 6) journaled in a bracket lug 71 on the'frame 19'. On the outer end of shaft '70 is keyed an operating handle 72. In the normal working position of the parts shown in Fig. 2, the lever 45 is exerting pressure against the spring 41, and this pressure is transmitted to the slide 22 through the nut 42 and rod 38, thus elastically pressing the slide 22 against the inner end of rod 35 and holding the applicator roll 24 in the exact relation to the web and the roll 18 determined by the adjustment rod 35. By swinging the handle 72 to the reverse position from that shown in Fig. 2, the block 40 through contact with the head 39 manifestly retracts the slide 22,

thus effecting a quick throw-out, in case the web should break or any other accident should necessitate the arrest of the web travel.

It will be observed that the frames 19 and 19' are entirely independent and disconnected, except that they are mounted on a common machine base 20. This is quite important, since the spacing of the rolls 18 and 24 is very finely adjusted, and to insure exact uniformity in the thickness of the coating applied to the web as it passes between said rolls, it is essential that this spacing remain absolutely constant. I have found, in practice, that where the pressure rolls are mounted on the same frame with the applicator roll, the thrust of the pressure rolls on the frame may strain the parts of the latter to such an extent as to disturb the exact spacing of the applicator and abutment rolls, and thus produce a coating of greater or less thickness than desired.

From the rolls 18, 24, the coated web passes directly onto the surface of a drying drum 46, and associated with the latter is a device for bathing the freshly coated surface of the web with a current of heated air to dry the coating sufliciently to prevent the same from clinging or sticking to the surfaces of the subsequent drying rolls. In Figs. 3, 4 and 5 I have illustrated one practical mechanical form of such drying apparatus. A hood 47 above the drum 46 is attached at opposite sides of its lower end to a pair of arcuate beams 48 that overhang the ends of the drum 46. At-

tached to and extending between the beams 48 is a group ofsuction boxes 49, the open ends of which register with openings 50 in the beams 48. As shown in Fig. 4, these suction boxes 49 are narrowly spaced to permit the down flow of heated air between adjacent sidesthereof, which form tuyeres 51a. The bottom walls of the boxes 49 are spaced from the periphery of the drum 46 a sufiicient distance to pemiit a narrow flow passage for the air between the bottoms of the boxes either the intake or discharge connections of the blower.

To render the flow of heated air substantially uniform throughout the length of each suction box, the latter is preferably equipped with a pair of oppositely extending baiiie plates 53 that at their inner ends are pivotally connected to a nut 54 carried by a vertical adjusting screw 55 that is rotatably mounted :in a central corer 56 and provided with a turning knob 57. The outer ends of the bafiles 53 are forked and straddle headed pins or studs 58 mounted in the top' walls of the boxes. These bafiies have the effect of gradually narrowing the cross section of the box from its ends to its center, and thereby, by a suitable adjustment of the battles, the suction at the slot 51 may be rendered substantially uniform throughout its length. The rate of flow of the heated air may be regulated by sliding dampers 59 controlling the openings 50 and locked in adjusted posigiion by set screws 60 ina manner obvious from g. 3. a The entire air supply unitabove described my sure at the intake of the exhaust fan 7 be, and preferably is, suspended over the drum 46 from a suitable overhead support by means permitting an accurate adjustment of the spacing between the tuyeres 51a and the surface of the drum. I have obtained excellent results by making the tuyeres 51a one-quarter of an inch wide and spacing them one-quarter of an inch from the coated surface of the paper; but, of course, these dimensions may be more or less varied as desired.

With reference to the air pressure employed, I have obtained good results by making the air pressure at the discharge of the supply fan 7 inches H2O staticpressure, and the suction presinches Of course, these air pressures may be varied by means of the dampers 59 and also by a suitable damper (not shown) located in the supply duct. The air temperature is preferably maintained at between 200 F. and 230 F., depending'on humidity conditions in the machine room. The supply'fan pressure to the hood 47 that is beyond the supply-regulating damper is about 6 inches H2O static pressure, while the exhaust pressure is carried at about 6 inches static pressure. The amount of air supplied for a drum of 60 inch diameter and 116 inch length is approximately 14,000 C. F. M. and the amount exhausted is approximately 15,000 C. F. M., the difference being caused by leakage around the hood.

v The complete drying of the web as it emerges from the drying hood may be effected by any static pressure.

suitable additional drying equipment, that il-' lustrated in Fig. 1 being a series of drying cylinders 61 and 62 and carrying felts 63 and 64 therefor structurally identical ith the similar equipment between the wet end of the machine and the filling and coating devices. From the last drum 61, the coated and dried web will prefer-v ably pass to the usual calender rolls.

As above'stated,-by means of the adjustable coating mechanism illustrated in Fig. 2, the weight and thickness of the coating may be quite widely varied. In actual practice, the weight of the coating applied may run anywhere from 5 to 50 pounds to the ream, a coating of approximately 12 pounds per ream giving excellent results.

The present invention is very useful in connection with the manufacture of papers containing a substantial percentage of groundwood stock, such as wall papers, which in time fade, lose their pure white appearance, and acquire a dull brownish tint but it is by'no means limited to the manufacture of such papers.

I claim:

1. The improved continuous process of making coated paper, which comprises forming a web, then removing a substantial amount of water therefrom by evaporation, then subjecting the partially dried web to heavy pressure and applying an initial upon said initial coating by a coated surface moving in the reverse direction to produce a smooth coating of the required thickness.

'2. The improved continuous process of makin coated-paper, which comprises forming a web, then removing a substantial amount of water therefrom by evaporation, then subjecting the partially dried web to heavy pressure and applymoving in the reverse coating thereto, and then acting ing an-initial coating thereto, then acting upon said initial coating by a coated surface moving in the reverse direction to produce a smooth coating of the required thickness, and finally completing the drying of the coated web.

3. The improved continuous process of makin coated paper, which comprises forming a web, then partially drying the same, then propelling the same into surface contact with a film of liquid filler, then subjecting the web to pressure sufficient to remove excess filler and intimately incorporate the remainder of the filler with the surface stratum of the web, and then directly applying a coating to the filled surfaceof the web.

, 4. The improved continuous process of making coated paper, which comprises forming a web, then partially drying the same, then propelling the same into surface contact with a film of liquid filler, then subjecting the web to pressure sufl'icient to remove excess filler and intimately incorporate the remainder of the filler with the surface stratum of the web, and then directly applying a coating to the filled surface ofthe web, and then subjecting said coating to heat to dry the same.

5. The improved continuous process of making coated paper, which comprises forming a web, then partially drying the same, then propelling the same into surface contact with a film of liquid filler, then subjecting the web to pressure sufficient to remove excess filler and intimately incorporate the remainder of the filler with the surface stratum of the web, then directly applying a coating of greater thickness than said filled surface of the web, and then applying heat directly to both surfaces of the web to dry the same.

,6. Apparatus adjunctive to a paper making machine for coating the web as it comes from the wet end of said machine, comprising, in combination, means for removing a substantial amount of water from the web by evaporation, means for subjecting the partially dried web to heavy pressure and for applying an initial coating thereto, and means for applying a smooth second coating of the required thickness to said initial coating.

'7. Apparatus adjunctive to a. paper making machine for coating the web as it comes from the wet end of the machine, comprising, in combination, means for removing a substantial amount of water from the web by evaporation, means for subjecting the partially dried web to heavy pressure and for applying an initial coating thereto, and a coatingroll for applying asmooth second coating of the required thickness to said initial coating, the coating applying surface of said roll direction to said web.

8. Apparatus adjunctive to a paper making machine for coating the web as it comes from the wet end of the machine, comprising, in combination, drying cylinders over which the wet web is passed to remove a substantial amount of water from the web by evaporation, means for subjecting the partially dried web to heavy pressure and for applying a surface filler thereto, a coating roll for applying a smooth coating of the required thickness to the filled surface, the coating surface G. BRIGHT.

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