US2059880A - Method of sizing photographic paper - Google Patents

Description

Nov. 3, 1936. G, T, LANE 2,059,880

METHOD OF SIZING PHOTOGRAPHIC PAPER Filed March 12, 1955 2 Sheets-Sheet 1 Nov. 3, 1936. G, T, LANE 2,059,880

METHOD OF SIZING PHOTOGRAPHIC PAPER Filed March 12, 1935 2 Sheets-Sheet 2 Patented Nov. 3, 1936+ I UNITED STATES 2,059,880 METHOD or SIZING rno'roomrmo PAPER Gerould '1. Lane, Rochester, N. Yl, assignor, by

inesne assignments, to Eastman Kodak Company, Jersey City, N. J., a corporation of New Jersey Application March 12, Masai-m1 No. 10,635

L 8Glaims. (01.91-68) This invention relates to paper making and particularly to a method of andapparat-us for sizing paper. One object of 'my invention is to provide an improved method of sizing paper by which the size canbe made to fully penetrate ,the paper web. Another object of myinvention is to provide a method of sizing paper including driving out the air in a paper sheet; and permitting atmospheric pressure to cause the size to 10 penetrate the sheet. Another object of my invention is to provide amethod of sizing paper by steaming and excluding air from the steamed paper until after it passes, through the sizing bath. Another object of my invention is to provide a simple machine for aspirating paper before sizing. Another object is to provide a machine in which paper is passedagainst a countercurrent flow of gas. before entering the size. Still another object is to provide an operable steam chest at the entrance to a sizing bath, and other objects will appear from the following specification, the novel features being particularly pointed out in the claims at the end thereof.

In the-past, sizing has been one of the most difficult steps to accomplish properly in paper making. It is desirable to use a concentrated size so that a single treatment will size the paper with size of the desired strength, but if concen; trated size is used, only the surface is treated and but little size penetrates to the interior of the sheet. Since the fibers are not cemented well together, the resulting sheet is not strong.

' On the other hand, if thin or dilute size is used, the sheet may be wetted quite fully, but

the .dilution is such that the fibers, whilewetted, are not properly cemented together because so little size gets into the sheet. Here too, the sheet is not nearlyas strong as it might be.

' Consequently, sizing has generally been a com- 0 promise in which paper strength has been j v definitely sacrificed. If proper strength size is made to penetrate throughout a sheet or web of -paper,' so that all the fibers are cemented together, a paper sheet can be made many-times 45 stronger than the present'practice with fibers of the same length and character.

It is to overcome these sizing difficulties, which.

,can completely size paper as fast as the web penetratefully into the body of the sheet, and to actually over-size paper by the method and apparatus which will now be described.

Coming now to the drawings in which like reference characters denote like parts throughout: 5

Fig. 1 is a side elevation partially in section, showing an apparatus for sizing paper constructed. in accordance with and embodying a pre-- ferred form of my invention.

Fig. 2 is an enlarged fragmentary sectional '10 view of the apparatus shown in Fig. l.

Fig. 3 is an enlarged cross-section of the steam chest used with a preferred form of my sizing apparatus.

Fig. 4 is a fragmentary detail of a'secondem- .15 bodiment of my invention showing the means for adjusting the width of the paper entrance to the steam chest. 7

' Fig. 5 is an enlarged sectional view taken, on line 55 of Fig. 4. I

In accordance with the drawings wherein a preferred form of my invention is shown, I may provide an apparatus for sizing paper, as shown in-Fig. 1, wherein there is a tank Iwhich is adapted to hold sizing solution 2 which may, be 5 brought up to a predetermined level 3. At one end of the tank I, there is mounted a steam chest designated broadly as 4 in which there is ports a roller I0 pver which a paper web P may 35 be drawn directly from the drying rolls I I.

Beneath the steam chest a guide roller I2 is mounted, and the paper web P is drawn beneath this guide roller through the sizing solution around a second guide roller I3 mounted in 40 the opposite end of the sizing tank I. Above 'roller I3, there is mounted a pair of squeezing rollers I4 and I5. These rollers may be of granite and rubber, as is customary, and are for squeezing off the ,excess sizing remaining. on

the paper web P as it is .drawn from the sizing solution. The paper web passes continuously 'over a second series of drying rollers I6. This sizing apparatus is arranged to permitthe paper web P to move continuously. at a relatively high speed. In' fact I have found that the sizing operation is no longer a'limiting factorin the speed of operation of the, machine and that I can be formed on the making wire.

As indicated in Figures 2 and 3, the steam chest 4 preferably consists of two sections I1 and I8 which are hinged together at l9, so that one section can swing relative to the other. I provide bolts or screws 20 at the end opposite to the hinge 19 these fasteners, passing through the cooperating flanges 2| and 22, so that the two sections can be held firmly together after the paper has been threaded through the steam chest in initially threading up the 'machine.

I prefer to provide the steam chest 4 with a covering of suitable insulation material, such as asbestos cement, or the like, as indicated at Fig. 3 at 64, since this is useful in keeping the interior of the steam chest at a constant temperature and preventing too great a loss of heat. I also prefer to provide drains 32 and 33' in each bottom section to carry off any water which may form if steam condenses.

Referring to Fig. 3,the steam chest 4 is provided with a pair of walls 24 and 25 which are fastened to flanges. 26 and 21 at the upper walls 28 and 29 of the steam chest, the lower edges 3|! andv II of these plates being spaced some distance above the bottom walls 32 and 33. These converging walls form an aspirator when steam passes upwardly between these walls about both sides of the paper web P as it is moving downwardly between the walls. The countercurrent flow of steam either prevents the air inside of the paper web from entering the steam chest 4, or sucks the air out of the sheet.

The paper entrance designated broadly as 35 consists of a slot between two L- shaped members 36 and 31 which may be adjusted relative to each other to vary the space between them.

This may be done'by means of knurled knobs 38. The adjustment of these two members controls, to a large extent, the aspirating eifect which is obtained by permitting steam to enter through the pipes Sand 6, altho the adjustment of valves 1 and 8 likewise controls the aspirating of the paper web.

In order to prevent the steam from rushing in through the pipes and 6 and displacing walls 24 and 25, and in order to make the steam circulate rapidly and satisfactorily, I prefer to provide similar brackets 40 on each of the side walls 4| of the steam chamber and, to provide the brackets 40 with downwardly extending baiiie plates 42. As will be seen by the arrows, these plates deflect steam entering through these pipes members.

so that it will be distributed uniformly without undue pressure on any part of the steam chest.

While I circulate steam in the steam chest quite freely, and at a high velocity, I prefer to use it in such a way that no appreciable pressure is built up in the steam chamber and so that the steam entering the pipes 5 and 6 will pass up through the aspirator and out of the parr entrance. Thus the pressure is insuflicient to cause the steam to pass out through the paper exit beneath the surface of the size. I have found that steam from a 20 lb. line passing into the steam chest from a inch pipe produces the desired results although this is only by way of example and does not limit my invention.

The paper exit is preferably formed by the bottom walls 32 and 33 of the hinged sections, and I likewise prefer to provide two similar upstanding flanges 44 on the two sections which are spaced apart a sufficient distance to allow the paper to pass freely down between. these It will be noted that the bottom walls vcessful sizing. As the paper passes of the steam chamber are substantially at, or below the level 3 of the size 2 in the tank I and that the paper web passes directly from the paper exit into the size without being allowed to come in contact with air. The reason for this is as follows.

As the paper comes in over the guide roller 7 l0, while it may have been partially or entirely tween the fibersof the sheet coming from the drying rolls H. I

This takes place very rapidly. It is possible to operate my sizing machine with the paper moving at relatively high speeds, such as 120 feet per minute. In fact my improved method of sizing permits machines to be run at any commercial speeds. Thus, the actual time of the steam treatment is exceedingly brief because I have found that a steam treatment tank, approximately twelve inches long, will be entirely satisfactory. If the paper web should be'traveling 120 ft. per minute it would therefore be steam treated in about a half of a second. Of course, these figures are given by way of illustration only, and the size of the steam chest may be varied to suit the particular conditions under which the paper is-made. The necessary step is to treat the entire sheet with a blast of steam.

As the paper passes down between the Venturi plates 24 and 25, the air is entirely removed from the interior of the paper web. In fact, I believe the blast of steam prevents any air being carried into the steam chest 4. The web is thenpassed directly beneath the surface 3 of the'size 2. The

size is, of course, cooler than the steam, and, any' steam in the sheet will be condensed, but one part in fourteen hundred of water resulting from such condensation is immaterial. No air is permitted to contact with the paper web after it passes into the steam chest and before it enters the sizing solution. Atmospheric pressure or the pressure on the sizing solution immediately forces the size thoroughly into and through the sheet and completely sizes the paper. In fact, I have found that I can place so much sizing in a paper sheet that the resulting paper is unsatisfactory. This, however, can be very easily prevented by controlling the amount of steam through the valves 1 and 8, and/or controlling the width of the paper entrance lips 36 and 31. v The less the sizing which is required, the less steam which needs to be admitted to the steam chest 4. The sizing, of course, can also be controlled by the viscosity of the sizing bath.

.One of the features of my present invention is that my method permits the use of a sizing bath of high viscosity and at the same time provides a means for causing such a sizing bath to penetrate into the paper. Such a size may be a 6 per cent solution. A 2 per cent solution may be considered a normal one. Since air has been entirely removed from the paper web, the sizing bath is forced into the sheet, even though it is considerably more viscous than the bath normally used.

In Fig. 4 I have shown a modified form of ad'- justing mechanism for the lips 36 and 31 of the paper entrance plates. As indicated in Figs. 4

and 5, the rails 50 and 5! are provided with opena I although it is more economical to carry out my ings 52 and 53 in which cams 54 and 55 rest, these cams being movable about the shafts 56 and 51 by means of the knurled heads 58 and 59.

In this modification of my invention, both rails are made adjustable to and from each other, whereas in the form shown in Fig. 3, only one rail is made adjustable to and from the other, which may be fixedly mounted.

It is immaterial just how this adjustment is made, the adjustment being primarilynecessary in initially securing the proper amount of steaming of the sheet. For instance, it is possible to cause more or less aspirating effecton the sheet by regulating the width ofthe paper entrance to the steam chamber. It is also possible to vary the effect of the steaming by altering the amount of steam through an adjustment of the valves 1 and 8, and the viscosity of the size can also be used to control the amount of sizing.

The method of treating a wet or dry strip of paper by means oi. a short contact with rapidly moving steam and passing it directly through a sizing bath without permitting air to come in contact with-the sheet has produced animproved product, andwhile it may not be clear as to exactly what occurs inthis steam treatment-that is, as to whether the air in the sheet is not per- I 'mitted to enter the steam chamber at all or whether'the air is'sucked or drawn out by the steam as it passes in a countercurrent fiow over the sheet, it is not important and I do not wish to confine myself to any particular theory of operathe sizing operation. I have found paper made in known machines can be increased in strength about fifty per cent (Mullen test) the sole difference in the two papers being the .use of my improved method of sizing, and I have found that the fold test (Schopper test) indi- 'cates a strength increase approximately ten times. The figures vary somewhat with the stock used, but illustrate the results which can be obtained by utilizing my improved method and apparatus for sizing.

Moreover, I have found that paper which has been insuflicientiy sized can be re-sized by rerunning through a'steamsizing machine, and thefstrength of the paper can be greatly increased by the additional size which can be placed in the web; Thus my method may be carried, out as a separate operation entirely successfully with previously sized or unsized paper,

' ately preceding its plate as included in the scope. of my invention.

all such forms of machines, and methods as may come within the terms of the appended claims.

Having thus described my invention, what I claim as new and desire to be secured by Letters Patent of the United States is:

1. The method of sizing paper which comprises treating paper with high velocity steam,

excluding air from the paper, and plunging it into a sizing bath.

'2. The method of sizing paper continuously which comprises treating a moving paper web with a countercurrent flow of steam immedibath.

3. The method of sizing a continuously moving paper web which comprises passing the paper web through high velocity steam passing in an opposite direction to that in which the paper passes and immediately submerging the paper in size.

4. The method of a continuously and rapidly moving paper web which comprises treating the paper web with a short treatment of high velocity steam and. passing the web immediately into a sizing bath.

5. The method of sizing a continuously movpaper web that consists in treating a small area of the web very briefly with a steam blast and plunging the steamed paper directly into the sizing bath.

6. The method of sizing paper which consists in blowing a 'blast of steam across the entire sheet just before said sheet is plunged into a sizing bath.

7. The method of sizing paper which comprises subjecting a continuously moving P per web to the action of flowing steam, replacing the air in the sheet withsteam and causing the" steam-filled sheet to pass beneath the surface of a sizing bath, condensing the steam in the sizing bath and impregnating the sheet with size. 8. The method of sizing a long paper strip which comprises moving the strip continuously through flowing live steam to carry away air in the sheet,

introduction into the sizing

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