METHOD OF AND APPABATTTS FOB SIZING PAPEB

1,195,888.

To all whom it may concern:

Be it known that I, Henry M. WheelWright, a citizen of the United States, residing at Ware, in the county of Hampshire 5 and State of Massachusetts, have invented a new and useful Method of and Apparatus for Sizing Paper, of which the following is a specification. The principal objects of this invention are

10f to provide an improved method of treatment during the manufacture of paper, whereby one wetting, and consequently one drying, of the web will be eliminated, thus reducing the cost of manufacture, the size of the plant,

15 and the time required, as well as doing away with the well-known difficulties encountered when a previously dried web is subjected to moisture on the paper machine and consequently swells.

20 Eeference is to be had to the accompanying drawing in which—

Figure 1 is a side view partially diagrammatic in form of a well-known type .of paper making plant arranged for carrying put

25 this method, and Fig. 2 is an enlarged view of the apparatus constituting a part of this invention.

Heretofore, paper has been made for example, on a Fourdrinier machine, then sub

30 jected to the wet pressing process, drying and calendering and thereafter sized by immersion in a size in a suitable tub. This, of course, wets the paper and necessitates a further drying. If the paper is to be sub

35 jected to the size after it has been completely dried, immersion is the most convenient and inexpensive way of doing it. The stock cannot be immersed in the size before it is dried because it is not in sufficiently firm condi

40 tion to stand wetting at that time and it would all go to pieces under such treatment. I have discovered, however, that the stock can be sized, especially by means of feculose or thin boiling starch compounds, during its

45 travel from the paper-making machine to the driers, provided this size is applied to the surface of the web without immersing the web in a body of liquid. In order to do this I subject the web to all the wet pressing

50 operations to which it is usually subjected, and apply the size during the last wet pressing operation. I find that this is a practical and efficient way of sizing the paper, that when the sizes above mentioned are em

65 ployed in this manner and at this stage of the paper making process the size will not

stick to the drying drums and not become injured in any way by the drying operation, and it will be obvious that this does away with the rewetting of the web after it is 83 dried and entirely eliminates the subsequent redryirig operation usually necessitated in making sized paper.

Referring particularly to the drawing, I have shown the invention as applied in that 65 type of paper making in which the pulp passes through a Fourdrinier machine A of any desired type. It passes as usual from the couch rolls a to the first wet press B, from there to the second press C, and in 70 ordinary practice by this time about fifty per cent, of the moisture has been squeezed out of the stock but it is still a comparatively weak paper because it has not been subjected to any drying or calendering operations. 75

I have shown herein the third wet press D to which the paper is next directed and this is illustrated more in detail than the others because it is the only element of this apparatus which is changed by this process. 80 In this press there is a bottom press roll 10 and a top press roll 11. The bottom press roll dips directly, preferably, into a starch bath 12 and there is a starch bath 13 adjacent to the top press roll having a sort of 85 fountain roll 14 dipping into it and engaging the surface of the top press roll 11. I preferably use a scraping blade 15 on each of the press rolls to insure the delivery of a uniform film of size to the surface of the 90 web as it passes between them. It is to be understood that these press rolls accomplish two objects. They act as smoothing rolls for the web in addition to applying the size to the surface thereof. It is to be understood 95 that the web of paper does not have to be supported on a felt while passing through the press D, which, although called a wet press does not extract any appreciable amount of moisture. It is then led to the 100 drying drums E (only a part of which are illustrated herein). It will be understood that with the exception of the extraction of moisture by the wet presses, the entire drying operation is performed after the application 105 of the size.

I have found that the character of the size used is an important factor in the success of this method. The size should be of one of the so-called soluble, or converted 110 hydrolyzed starches or starch compounds, preferably feculose, which is a partial ace

tate of starch, but the thin boiling starches in general can be used. I prefer to use starch products which yield a gelatin-like film when a ten per cent, to twenty per cent. 5 solution is allowed to dry on a glass plate and this is a characteristic of the partial starch acetates commercially known as feculose. This size should be used hot so that it will penetrate the surface of the web to a 10 sufficient degree.

The invention is suitable for use for making paper for off-set printing, for example, when size alone is xised; also writing papers can be made to great advantage and many 15 other kinds of surface-sized papers. It will be understood of course that colors, loading materials, etc., can be added to the starch for the usual purposes to permit of the use of the method throughout a wider field.

Although I have illustrated and described only a single type of paper-making machine, it will be understood that the invention is applicable to other paper processes and cylinder paper machines and furthermore, that in the construction of the sizing press can be made by any person skilled in the art and that the exact number of wet presses can be varied without departing from the scope of this invention as ex30 pressed in the claims. Therefore, I do not wish to be limited in these respects, but

What I do claim is:—

1. The method of sizing paper, which consists in leading the paper from a wet press,

35 applying sizing to the surface of the paper while in the air, and thereafter drying and calendering the web.

2. The method of sizing paper, which consists in forming the web on a Fourdrinier

40 machine, leading it through a series of wet presses, applying a size of soluble starch or starch compounds to the surface of the web in the last wet press, and thereafter subjecting it to the entire drying operation.

3. The method of sizing paper, which consists in forming the web, wet pressing it to extract part of the moisture, treating both

20

25 changes

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surfa'ees simultaneously to a size of converted hydrolyzed starch or starch compounds coming from different sources before 50 it is otherwise dried, and thereafter drying the web.

4. The method of sizing paper, which consists in applying to the previously formed web of paper after a portion of the moisture 55 has been extracted in a wet press, feculose size by means of a press roll to the bottom

of the web, and also applying feculose size by means of a press roll to the top of the web, and then drying. 60

5. The method of sizing paper, which consists in leading the paper through a series of wet presses, while the paper is in the last wet press applying starch size to the bottom and top press rolls of said press, and thus 65 coating the two surfaces of the web with the size, and then leading the web to the first drier cylinder.

6. A wet press for a paper making machine comprising a pair of press rolls, and 70 means for coating each of said rolls independently with size so as to apply the size

to the web as it passes between them and as it is being pressed by them.

7. In an apparatus for the manufacture of 75 paper, the combination with a paper-making machine, of a series of wet presses, the last wet press comprising a pair of press rolls, means for coating each of said rolls independently with size so as to apply the 80 size to the web as it passes between them, said last wet press being in position to receive the web' directly from the other wet presses, and a drier having its first drying cylinder in position to receive the web from 85 said last wet press.

In testimony whereof I have hereunto set my hand, in the presence of two subscribing witnesses.

HENKY M. WHEELWRIGHT.

Witnesses:

Lillian G. Tbeen,
Jtjlia F. Sherman.