US2798414A

US2798414A - Press roll couple and felt arrangement

Info

Publication number: US2798414A
Application number: US322611A
Authority: US
Inventors: Gerald D Muggleton
Original assignee: Combined Locks Paper Co
Current assignee: Combined Locks Paper Co
Priority date: 1952-11-26
Filing date: 1952-11-26
Publication date: 1957-07-09
Anticipated expiration: 1974-07-09

Description

July 1957 G. D. MUGGLETON PRESS ROLL. COUPLE AND FELT ARRANGEMENT Filed Nov. 26, 1952 O u L my EU M m. D D L A R E V. B

XEAQW ATTORNEY PRESS ROLL COUPLE AND FELT ARRANGEMENT Gerald D. Muggleton, Appleton, Wis., assignor to Combined Locks Paper Company, Combined Locks, Wis., a corporation of Delaware Application November 26, 1952, Serial No. 322,611

1 Claim. (Cl. 92+49) This invention relates to paper making and particularly to handling and treating the web at press rolls and breaker stacks.

Particularly in the making of light weight papers. (20 /2 lb. per ream, size 24 X 36-500 sheets), there is danger that the press roll will lap up and wrap the sheet or web, thereby breaking the web and perhaps damaging the roll and felt. Even when the web is not broken, certain types of paper (ground wood book, catalog) have small particles (crumbs) which are drawn from the web by the adhesion of the upper roll and must be removed from the surface of the roll before again contacting the web. These conditions have only been partially eliminated by the conventional use of the well known doctor on the upper press roll.

Using the present condensation method, it is impossible to control the amount of moisture on the surface of the smoothing rolls in the breaker stack between two. sections of a drier. Variations in humidity which cannot be easily avoided in commercial installation alter the amount of moisture on the surface of such rolls.

One of the objects of this invention therefore is to provide apparatus for preventing adhesion between the web and the press rolls and consequent lapping and wrapping of the web, and eliminating the picking up of crumbs by the press rolls.

Another object of this invention is to provide apparatus for supplying controlled amounts of moisture (including, if desired, small amounts of paper treating material) to the surface of smoothing rolls in a breaker stack.

The first object is obtained by using a wetting roll to directly apply moisture (containing other ingredients, if desired) to that press roll contacting the Wet web ahead of the nip. The film of water on the surface of the roll breaks down the adhesions and eliminates the tendency to lap the Web or pick up crumbs from the web surface. In the presence of the water film, the web continuously and uniformly cleans the press. roll without wear. A doctor blade without a wiper may be used in starting the web and as a safety factor to. pick up any crumbs which might adhere to the surface of such roll. However, when so used with a wetting roll, only a very light pressure is needed between such blade and such roll. In most conditions the doctor blade may be entirely out of contact with the surface of the roll.

The second object is obtained by using wetting rolls to apply a controlled film of moisture to the surface of both upper and lower rolls of the breaker stack. 7

The novel features, which are considered characteristic of the invention, are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawing, in which:

States Patent 2,798,414 Patented July 9, 1957 Fig. l is a diagrammatic view in side elevation of a first press assembly embodying the present invention;

Fig. 2 is a diagrammatic view in side elevation of a second or third press assembly embodying the present invention; and

Fig. 3 is a diagrammatic view in side elevation of a breaker stack assembly embodying the present invention.

The web of paper 10 supported on a felt 11 (not separately shown in Fig. 1) is advanced from the wet end of a paper making machine to the nip of the first press arrangement. This press has a lower roll 12 and an upper roll 14 forming a, nip therebetween. The roll 12 may have a rubber surface to carry the felt. The upper roll 14: may have either a hard or a soft surface. It is preferable for leveling the paper and for even expression of the water in the web that the surface of the upper roll be roughened by grinding, sanding, or lightly cutting with a lathe tool. Such surface also permits the use of a higher pressure in the press without sticking and thereby helps to increase the capacity of the drier section by eliminatingmore water at the press.

In order to keep the web from lapping and to eliminate substantially entirely the pick-up of crumbs from the sheet by the surface of the roll 14, such surface is continuously supplied with a uniform, film of water by a moistening roll 16 supplied by a pan 18. This moistening roll has a soft rubber surface so that the water is applied to the surface of roll 14, in an even controlled film. While a hard rubber covering may be used, the soft rubber eliminates need for undue precision in mounting and; adjusting such a moistening roll relative to the metal roll. The rolling nip with overflow between the moistening roll 16 and. the press roll 14 prevents the accumulation ofsuch minute amounts of crumbs or fibers which, in some conditions, might adhere to the surface of roll 1.4, and thus stops the formation of detrimental slush.

With some types of stock, it is advisable to add to the water supplied bythe pan 18 small amounts of starch, clay, mineral spirits, formaldehyde, or other soluble compounds which increase the action of the Water in preventing the sticking of the web to the press'roll. In such case it is practical to provide the moistening roll 16 with endgates or other well known equivalents whereby a small pool of such surface treating material may be maintained at the nip. This is an economical way of utilizing small amounts of such special materials.

It is desirable to have a hinged doctor 20 which may be made active under certain conditions. When there is some. slight pick-up, because of the unusual wetness of theweb (for example, moisture) orthe presence of an unusual amount of pitch or other sticky substance, such doctor may be placed in contact with the roll 14 under very light pressure. The doctor will pick up the crumbs. without creating appreciable friction or wearing and smoothing the surface ofgthe roll 14. In normal conditions, however, the doctor is used only for starting up the web and is lifted after the web is started. The doctor 20 need not extend for the full length of the roll 14. A relatively short fiat hinged doctor, say, eight inches long, may be used for the purpose of starting the web.

The use of the moistening roll 16 to maintain the moisture film on the press roll 14 thus saves press power by eliminating the friction caused by the type of doctor which extends the entire length of the roll and presses strongly against such roll and decreases the cost of maintaining the surface of the roll 14 by preventing wear and smoothening thereof. Further, because of the non-pickup, the surface of the paper is greatly improved, less breaks and loss of time occur, and the operator is encouraged to operate the paper machine at higher speeds. Because more moisture content can be removed at the presses, the usual bottleneck at the driers is eliminated and the capacity of the paper making machine increased.

In Fig. 2 there is illustrated the arrangement for a reverse press or second or third press. The web 10, supported on a reverse press felt 11, is advanced from the first press to the nip between lower press roll 22 and upper press roll 24. The under side of the web thus comes in contact with the upper press roll 24. The lower press roll 22 may be identical with the lower press roll 12 of the first press, and the upper press roll 24 may be identical with the upper press roll 14 of the first press. A moistening roll 26 and pan 28 substantially identical with wetting roll 16 and pan 18 of the first press is mounted so as to be in contact with the roll 24 in advance of the nip between rolls 22 and 24. A hinged doctor 30 may be placed as shown so that it is in advance of the moistening roll 26. Such doctor 30 functions in exactly the same way as the doctor 20 of the first press rolls. The functioning of the moistening roll 26 on either a second or third press is identical with that heretofore described in connection with the first press.

In Fig. 3 there is diagrammatically illustrated a breaker stack arrangement which may be placed between two sections of a drier to impart smoothness to the surface of a paper web while such web contains a greater amount of moisture than is present at the end of the drying operation. It is easier to do the smoothing at this point as the web is more plastic and permits the smoothing to be done with less pressure, thereby preserving more bulk or caliper in the web. It has been the practice to cool the breaker stack rolls to condense moisture on the surface thereof to assist the smoothing operation. In

the arrangement shown, a lower breaker stack roll 32 and an upper breaker stack roll 34 each have smooth hard surfaces. In order to keep these surfaces clean they are supplied with a controlled uniform film of water by wetting rolls 36 supplied by pans 38 positioned in rotational advance of the nip between the rolls 32 and 34. Each of these wetting rolls and pans is constructed in substantially the same manner as the moisture rolls and pans heretofore described in connection with the press rolls. They preferably have a soft rubber covering so that they will evenly contact the surface of the rolls 32 and 34. By applying the film of moisture in this manner, it can be maintained uniform in spite of the varying changes in humidity. It has been found that an amount of moisture in excess of that obtainable by the previous condensation method will give more desirable results and prevent the tendency of the web to adhere to the surface of the rolls 32 and 34. Another advantage of the use of moistening rolls 36 on the breaker stack rolls 32 and 34 is the ability to use with the water other additives,

such as wetting agents, lubricants, and sizing agents. These additives can be used when the web is extremely sticky. They may be used to make the web less absorbent. In some instances formaldehyde may be added to a web sized with casein or other protein to make the web resistant to wetting. When additives are used, it is practical to provide the wetting rolls 36 with end gates 4 or the like whereby a small pool of water with such additives may be maintained at the nip.

Although several applications of the invention are shown and described herein, it will be understood that this application is intended to cover such applications, changes or modifications as come within the spirit of the invention or scope of the following claim:

, I claim:

An improved press roll arrangement for operating at high speeds to express moisture from a traveling web of light weight paper supported on a traveling felt comprising a lower press roll over which a felt travels, an upper press roll having a surface in rolling contact with a web of paper on said felt as it passes over said lower press roll to apply pressure between said rolls to said web and felt to extract moisture from the web, said surface of said upper press roll being roughened for leveling the paper and for the even expression of water from said web, a moistening roll having a soft rubber surface mounted in rolling contact with said upper press roll to form a rolling nip therewith, said rolling nip forming overflows for liquid accumulating therein, means for continuously supplying liquid to the surface of said moistening roll in sufficient quantities to form a pool in the nip between said upper press roll and said moistening roll, which liquid discharges from said overflows to carry away any accumulation of crumbs or fibres and to stop formation of detrimental slush, and a doctor temporarily engaging said upper roll for starting the web, said moistening roll being positioned to deposit an even film of said liquid on the surface of said upper roll prior to contact thereby with said web of paper to prevent adhesion between said web and the surface of said upper press roll and consequent lapping and wrapping of said web to eliminate the picking up of crumbs by said upper roll -without creating sliding friction between said upper roll and any other roll treating instrumentalities.

References Cited in the file of this patent UNITED STATES PATENTS 19,045 Rossman Jan. 5, 1858 592,186 Bedford et al Oct. 19, 1897 1,933,837 Arnold Nov. 7, 1933 1,934,543 Johnson Nov. 7, 1933 1,987,901 Hayward Jan. 15, 1935 2,209,761 Berry July 30, 1940 2,229,620 Bradner Jan. 21, 1941 2,243,604 Parkinson May 27, 1941 2,624,068 Dobry Ian. 6, 1953 2,649,386 Snowman Aug. 18, 1953 FOREIGN PATENTS 12,665 Great Britain 1904 16,315 Great Britain 1897 OTHER REFERENCES MacNaughton: Paper Trade J., August 27, 1942, page 36.

Egan: Paper Trade 1., October 25, 1945, pages 49-54.