US2005929A - Paper making apparatus and process - Google Patents

Description

June 25, 1935. E. E. BERRY PAPER MAKING APPARATUS AND PROCESS Filed Aug. 18, 1932 VE U5 Tm/Z199? Patented June 25, 1935 UNITED STATES PATENT OFFICE V 2,005,929 PAPER MAKING APPARATUS AND PROCESS Earl E. Berry, Beloi t, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application August 18, 1932, Serial No. 629,265

4 Claims. (CI. 9238) 5 such as the Harper and Yankee Fourdrinier machines in which the paper Web is transferred from the forming wire onto a carrier felt by means of a suction roll, said carrier felt transmitting the web to the drying section of the paper machine.

It has heretofore been known in the manufacture of paper to use a pickup type of felt for transferring a paper web from the forming part of the paper machine to a transfer roll and then to the first drying cylinder or directly to the dryingcylinder from the forming part.

the point where'said felt contacts the drying roll. As described 'in that patent, the use of a suction pressure roll at this point causes the nip to be sucked dry and eliminates the crushing of the web as it passes onto the drying cylinder. This arrangement also greatly lengthens the life of thepickup felt and has the added advantage of producing a drier sheet and lessen ing the load of the drying section of the paper machine. A

I have now found that if an additional suction roll is applied to aid in transferring the web from the forming wire onto the carrier felt, it is possible to manufacture heavier sheets of paper'than heretofore since the suction roll aids in the transferring of the sheet to the carrier felt while, at the same time, drying the web and forming it sufficiently to be carried unsupported on the felt. The suction roll is located after the web passes over the couch end of the forming wire, where the web is suspended from the wire. By means of my novel arrangement and use of the suction roll, the paper machine may be run at considerably higher speeds than was heretofore possible since the web is readily transferred to the carrier felt while being sucked dry at the same time.

It is therefore an object of this invention to provide a novel high speed means and method for making paper of practically all weights on Fourdrinier types of paper making machines that require the use of pickup felts.

It is a further object of this invention to provide a novel arrangement of pickup felt and forming part of the paper machine whereby the paper web may be readily transferred from the forming part of the paper machine to the pickup felt at high speed without crushing.

It is a further important object of this invention to provide a suction roll for cooperation with the pickup felt of a paper machine for transferring the web of paper from the forming part of the machine to the pickup felt after the web has passed over the couch roll.

It is a specific object of this invention to provide a Yankee or Harper type of Fourdrinier machine in which the web on the under side of the forming wire is transferred to a pickup felt by means of a suction roll and gravity.

Another specific object of this invention is to provide a paper machine of the Fourdrinier type in which the paper Web after passing around the couch roll on the forming wire is transferred to a pickup felt by means of a suction pressure roll acting through the pickup felt and cooperating with a top roll located in the loop of the forming wire.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawing.

This invention (in a preferred form) is illustrated on the drawing and hereinafter more fully described.

On the drawing:

Figure l is a diagrammatical view of a Yankee type of Fourdrinier machine equipped with a suction roll according to this invention.

Figure '2 is a diagrammatical view of a section of the Yankeetype of Fourdrinier machine showing an alternative arrangement of pickup felt cooperating with the forming wire to pre vent the paper web leaving the wire as it passes over the couch roll at high speeds before reaching the suction roll;

Figure 3 is a cross sectional View of the specific arrangement of suction roll and top roll, showing the manner in which the web is preferably transferred from the wire onto the pickup felt. A

As shown on the drawing:

In Figure 1 the reference numeral I indicates a head box from which the paper stock flows onto the usual forming wire 3. Said forming wire 3 is trained around a breast roll 5 and a couch roll 6 passing over the usual table rolls 4 and suction boxes 'I. As shown in Figure 1, after the paper web 2 on the forming wire 3 passes around the couch roll end of the table structure it contacts with a pickup felt lil immediately before the nip of a suction roll H and its cooperating top roll l2. The top roll i2 is located in the loop of the forming wire 3 so as to direct the forming wire and web over the suction area of the suction roll I I aiding in the extraction of water from the web and felt by exerting pressure in the nip. The roll I2 is preferably located so that the between the rolls H and i2 does not contact the web 2 until after it has been subjected to the action of the suction area iii of the suction roll. A roller i4 is also so located as to direct the felt ii? against the suction area i3 of the suction roll H before said felt contacts with the web In this arrangement the felt contacts the suction before the web and the web and felt contact the suction before the nip area between the rolls H and i2. The wire thereby leaves the web and felt tangentially of the nip area while suction is still being applied however. A guide roller 55 directsthe felt and web emerging from the nip area over that portion of the suction area i3 of roll H which is exposed beyond the nip area between the rolls l5 and [2. This arrangement of the felt, wire and the suction roll is better illustrated in Figure 3 wherein the respective areas are shown in detail. The parts shown in Figure 1 are marked with the same reference numerals in Figure 3.

As shown in Figure 3, the suction roll ii comprises a perforated cylinder 28 which may be covered with a resilient covering 2! if desired to further insure against the possibility of crushing the web in the nip area between the rolls l l and I 2. The perforations are only shown at M but extend entirely around the periphery of the roll. Within the suction roll is located a longitudinally extending suction chamber 23 connected at one or both ends to a suitable source of vacuum (not shown) said chamber being provided with a pair of spaced flanges 28 extending substantially the full length of the chamber. The suction area 13 from the interior of the chamber 23 is. thus radially directed toward the inner surface of the revolving shell 2f A floating head 25 mounted from the flanges 28 is provided with len thwise extending packing strips 26 and end packing strips 27 that are pressed against the inner surface of the shell 20 in a manner dcscribedand claimed in the U. S. patent to Berry No. 1,679,598.

In the heretofore used practice of transferring the wet web from the forming wire to the pickup felt on Harper, Yankee and the like type of Fourdrinier machines, it has been uniformly the practice to remove the web from the Wire by means of a top couch roll. At, high speed, in order to get rid of the water squeezed from the felt passing in the nip area of the upper and lower couch rolls, it was necessary to groove the bottom couch roll so that the water would drain off. As a considerable nip pressure is required between the top and bottom couch rolls to make the felt pick up the sheet from the forming wire, the grooves in the bottom couch roll tended to destroy the expensive forming wire and'greatly lessened its average life. In addition to this, it was necessary heretofore to run the pickup felt quite wet in order to make it lift the sheet from the forming wire. This of course lessened the amount of water that can be removed from the sheet before entering the drying section of the machine. To

remedy this it has been proposed to replace the upper couch with a suction roll In this arrangement however the suction was working against gravity and a high vacuum was required to drain the water. Furthermore the wet web had to be forced against the felt since suction alone would not insure its following the felt instead of the wire because gravity would tend to cause the web to follow the wire. The necessary pressure exerted betweenthe suction and couch roll while less than that necessary between two plain couches might be sufficient to crush the web and damage the wire.

According to the instant invention, the suction transfer roll is drilled with small holes, the felt and wire are both well supported and the Fourdrinier wire is not damaged in the least. By contacting the felt with the suction area of the suction roll before the Fourdrinier wire carrying the web makes contact with the same area, the felt is dried out and thus enabled to receive moisture from the sheet. The wire carrying the web, however, will make contact with the suction area before reaching the nip between the two rolls as described above sothat the air pressure on top of the sheet transfers it to the felt before the nip area is reached. Little or no pressure is exerted between the rolls. The top roll l2 being located inside the Fourdrinier wire, is so positioned in reference to the suction area of the suction roll that the air pressure holds the web to the felt after passing the nip area. It will readily be seen by those skilled in the art that the transfer of the sheet from the wire to the felt is positive in action and all of the troubles heretofore experienced with top pickup rolls acting in cooperation with couch rolls are thereby eliminated.

As shown in Figures 1 and 2, and as more fully described in the patent to Berry and Roberts No. 1,898,611, dated February 21, 193.3, the pickup felt Hi and web 2 are directed over a suction transfer roll I! to aid in the transfer of the web from the pickup felt ill to the drying roll l8. From the drying roll IS. the web 2 may be directed over auxiliary drying rolls l9 as is customary in the Yankee type, of Fourdrinier machines.

In case of high speed operation and when making the heavier type ,of light-grade paper there may be a tendency for the centrifugal force of theforming wire 3 in passing over the couch roll 5 to throw the sheet 2 off from the wire. To prevent this, the pickup felt can be so directed as to bring it around the couch roll 6 as shown in Figure 2 by eliminating the roll l4 shown in Figure l and positioning a directing roll 30 above and slightly ahead of the couch roll 6.

I claim as my invention 1. In combination with a paper making machine of the Fourdrinier type including the usual forming wire and partially formed paper web thereon trained around the couch roll, a suction roll contacting the web on the lower run of the wire, a pickup felt for receiving the web from the forming wire as it passes over the suction roll, means for directing said pickup felt over the suction area of the suction roll so that said felt is subjected to suction before contacting the web, an upper roll, located within the loop of the forming wire cooperating with the suction roll to aid in the transferring of the web to the pickup felt, means for directing said web and pickup felt to the drying section of the papermachine, a drying cylinder, and a suction roll cooperating therewith for transferring the web from the felt to said drying cylinder.

2. In the process of transferring. a paper web from the forming wire of a paper machine to a pickup felt, the step of first subjecting the pickup felt to suction to dry the felt and then bringing said felt into contact with the paper web without interrupting the suction.

3. In the process of transferring a paper web from the forming wire of a paper machine to a pickup felt, the steps of contacting the pickup felt with a portion of the suction area of the suction roll to dry the felt, contacting the dried felt with the web in the center portion of the suction area of the suction r011, directing said web, wire and felt between the nip of the suction roll and a cooperating top roll, and applying suction to the felt and web as they emerge from the nip while directing the wire away from the web.

4. In combination, a paper machine embodying a looped foraminous member for forming a web thereon, suction means engaging the lower run of said member at a position removed from the ends of the loop, a transfer medium engaged over said suction means, means for guiding said transfer medium into contact with the suction means before contacting the web on the foraminous member and pressure means inside the loop cooperating with said suction means.

EARL E. BERRY.

Images