US2386584A - Reverse press section for papermaking machines - Google Patents

Description

x Oct. 9, 1945. I BERRY 2,386,584

REVERSE PRESS SECTION FOR PAPER MAKING MACHINES Fi led Dec. 2, 1940 4 Sheets-Sheet 1 Q I UH ZZZ i1? jar/y E. E. BERRY 2,386,584

REVERSE PRESS SECTION FOR PAPER MAKING MACHINES Oct. 9, 1945.

Fild Dec. 2, 1940 4 She ets-Sheet 2 Oct. 9, 1945.

REVERSE PRESS SECTION FOR PAPER MAKING MACHINES 4 SheetsShee 3 Filed Dec. 2, 1940 E. E. BERRY Oct. 9, 1945.

REVERSE PRESS SECTION FOR PAPER MAKING MACHINES Fild Dec. 2, 1940 4 Sheets-Sheet 4 Patented Oct. 9,

GUNITEDS STATES PATENT OFFICE REVERSE PRESS SECTION FOR PAPER- MAKING MACHINES Earl E. Berry, Belolt, Wis., assignor to Beloit Iron Works. Beloit, Wia, a corporation of Wisconsin Application December 2. 1940, Serial No. 868,116

2 Claims.

In the conventional reverse press section for paper making machines a bottom felt is provided to engage the wire side of the newly formed wet paper web for conveying the web from the forming surface through the nip of a vertical roll press. A reverse vertical roll press next received the web and a second felt was passed through this reverse press so as to contact the top side or non-forming surface side of the web. However, in order to transfer the'web from the first felt to the second felt, an exceptionally long draw of unsupported web was required because the direction of movement of the paper web had to be completely reversed in order that the second felt could contact the surface of the web opposite to the surface contacted by the first felt. According to the present invention, the heretofore required long web draws are eliminated and felts with short web engaging runs successively receive opposite faces of the paper web thereon. The reverse roll press preferably has a vertical nip provided by rolls in horizontal alignment so that the web and second felt can pass through the nip therebetween in an'upward vertical direction. This eliminates the necessity for completely reversing the direction of travel of the web and avoids the long web draw between the felts. As a result the paper web is not stretched as in the conventional reverse press section.

The reverse press sections of this invention can be operated at high speed and have great water .removal capacity.

It is. then, an object ofthe invention to provide a reverse press section for paper making machines including a reverse roll press with an upward passage'vertical'nip for eliminating the contact the top side of the sheet with a second felt, and convey the web on the second felt through an upward passage vertical pressure nip with the wire side of the web against a press roll.

A further object of the invention is to successively support the wire side and the top side of a paper web on conveying felts and successively subjectthe exposed faces of the web to pressure against a rotating smooth surface.

Another object of the invention is to advance a web from the forming surface of a paper machine through pressure nips while supported on under felts and then direct'the web upwardly through a vertical passagepressure nip while covering the previously exposed surface of the web with another felt.

Other and further objects of the invention will become apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which disclose several preferred embodiments of the invention. It should be understood, however, that disclosures are by way of example only and that the invention is not limited to the specific modifications shown in the drawings.

On the drawings:

Figure l is a diagrammatic side elevational view of .a reverse press section according to this invention mounted-between the forming part and drier section of a Fourdinier type paper making machine.

Figure 2 is a fragmentary diagrammatic side eievational view of a reverse press roll section similar to that shown in Figure 1 but equipped with'a plain horizontal reverse press.

Figure 3 is a diagrammatic side elevational view of a reverse press roll section according to this invention mounted between the forming part and drier section of a Fourdrinier type paper making machine and having a plurality of vertical suction presses successively receiving the paper web through the pressure nips thereof as the same travels between the forming part and a reverse press.

Figure 4 is a'view similar to Figure 3 wherein some of the vertical presses and wherein the reverse press are composed of'plain rolls and stone covered rolls.

Figure 5 is a diagrammatic side elevational view of a reverse press section having a vertical press on each side of a reverse horizontal press.

As shown on the drawings:

In Figure 1 the reference numeral l0 designates a Fourdrlnier wire trained around a suction couch roll I I having a suction head l2. A paper web W formed on the upper run or the wire I is directed over the suction area of the couch roll and passed under a guide roll l3 into contact with the first or under felt M as it passes over a guide roll IS.

A first horizontal press roll assembly l3 composed of a suction roll I], a top roll l8 and a horizontally aligned plainroll l3 receives the web I and felt through the two nips thereof The snow tion roll I! is equipped with two suction heads 20 and 2| defining suction areas at the two nips.

As the web and felt are directed over the suction roll l'l through the. nip between the rolls I1 and I8 water and air is drawn from the web through the felt by the suction head 20 while the top roll |8 exerts a light pressure against the exposed surface of the web. The web then passes in a downward vertical direction through the pressure nip between the rolls l1 and I3 and the web is subjected to an increased pressure. The exposed face of the web contacts the plain roll Water and air are drawn through the felt H by the suction head 2| to remove water from the nip area and to assist the web dewaterin process.

The web, after passage through the nip between the rolls l1 and i3, is conveyed around the under side of the roll is over a guide roll 22 while the felt I4 is separated from the web and is directed under a guide roll 23.

From the guide roll 23 the web is trained over another guide roll 24 where it recontacts the web W on the same side of the web previously engaged by the felt.

The felt is then trained around another guide roll 25 away from the web W, is passed over still another guide roll 26 and thence directed downwardly around a stretcher roll 21 which can assume the positions shown in dotted lines to maintain the felt in a taut condition. After passage around the stretcher roll 21 the felt is directed upwardly and thence guided by a guide roll 28 around the guide roll l where it recontacts the web.

After leaving the first felt l4 the web W is conveyed around a guide roll 28 while unsupPOrted by any felt. The web then travels vertically uption roll 3| for collecting water sprayed out of the holes in the revolving cylinder of the roll.

A second felt 34 is trained under a guide roll 35 and thence upwardly through the nip between the rolls 3| and 32 where it contacts the top side of the web W. This side of the web was not previously engaged by a felt. The suction head 3 draws water and air from the web through the felt 34 and the felt protects the web from damage by the holes in the perforated cylinder of the suction roll. The bottom or wire side of the web directly engages the surface of the plain roll 32. This bottom side or wire side of the web was not previously engaged by a press roll.

After passage upwardly through the vertical nip provided by the rolls 3| and 32, the web is immediately separated from the felt 34 and directed over a guide roll 36. The web has now been sufliciently dewatered so that it is self-sustaining and can travel in an unsupported condition without danger of undue stretching or tearing. The web is directed over a guide roll 31 and thence around the drier drums 38.

The felt 34, after passage through the nip between the roll 3| and 32, is directed around a guide roll 39 and thence around a stretcher roll 40 which maintains the felt in a taut condition. After passage around the stretcher roll 34, the felt is trained around an outside guide roll 4| and over inside guide rolls 42 back to the guide roll 3 From the above descriptions it will be understood that the web W is first supported on the under felt l4 and conveyed thereon from the forming wire l0 through the first horizontal press roll assembly IS. The felt is momentarily separated from the web as it passes under the guide roll 23 so that the web alone can travel on the roll l3 of the press roll assembly. The felt again recontacts the web and supports the same for a relatively short run. The web alone is then passed vertically upwardly through an upward passage nip of a second horizontal press roll assembly 30-where it contacts a second felt 341 which engages the top side or non-wire side of the web. The plain roll 32 of the second press assembly 30 contacts the wire side of the felt. As a result, the two sides of the paper sheet are successively contacted with felts and with plain press rolls so that they are treated in an identical manner to prevent two-sided characteristics on the sheet. At the same time, however, it is not necessary to completely reverse the direction of travel of the sheet or to use long unsupported web draws= The roll I9 of the press assembly I6 and the roll 32 of the press assembly 30 are preferably Stonite or stone-surfaced to present desired finishing surfaces to the web without causing the web to stick to the rolls. The suction areas 29 and 2| in the assembly |8, and the suction area 32 in the assembly 30 can be maintained under a relatively high vacuum. It is also preferable to maintain the area Ha of the roll between the suction heads 20 and 2| under vacuum in order to prevent remoistening of the web as it passes between the high vacuum suction areas 20 and 2|. A vacuum of from two to five inches in the chamber l'la will be sufficient' to prevent remoistening of the web by centrifugal discharge of water out of the holes in the revolving cylinder of the suction roll.

Scrapers or doctors such as 43 can cooperate with the Stonite-covered rolls l9 and 32 to clean the surfaces of these rolls;

In Figure 2 parts identical with parts described in Figure 1 have been marked with the same reference characters. In Figure 2, however, the second horizontal press assembly 30a is a plain press instead of a suction press. The roll 3|a preferably has a rubber cover 44 therearound, but it should be understood that a plain press roll can be used. The roll 32a preferably is a Stonite-covered roll.

The guide roll 35a for the felt 34 is positioned forwardly of the vertical nip of the assembly 30a so that the felt 34 will contact the web W before the web reaches the nip, between the rolls 3|a and 3211. Likewise, the guide roll 23a for the web W is positioned forwardly of the guide roll 35a. This change requires a further spacing of the roll 25a for the felt H from the roll 24 in order that the web W will be supported on the upper run of the felt until it passesraround the roll 23a. A segmental cylindrical drip pan 33a is mounted around the under side of the roll Ma to pr e vent water from dripping on the felt 34.

Inthe modification shown in Figure 2, therefore, the web W is conveyed from the formingv surface through the first horizontal press assembly I6 in the same manner as described in Figure 1 and the web is then conveyed on the felt I4 to a point somewhat forwardly of the point shown in Figure 1, in order that the web can be contacted by the felt 34 before it reaches the nip of the'second horizontal press roll assembly 36a.

in Figure 1 have been marked with the same ref erence numeral. As shown in Figure 3 the suction head Hit of the suction couch roll is wider than the suction head l2 shown in Figure 1 so 2,386,5 4" I e I The press roll' assembly 5! is equipped'witha" Stonite surfaced top'roll II which can be cleaned by a doctor I2.

as to define a wider suction area for further dehydration of the web W as it passes thereover. This wide suctionarea will hold the web on the wire 1 III as the wire revolves downwardly around the couch roll thereby eliminating the necessity for a guide roll such as l3'shown in Figure l.

The horizontal press assembly 30 is substantially identical with the press assembly shown in Figure 1 with the exception that the felt. 34 is passed upwardly from the nips of the press roll assembly30 around an inside roll 39a instead of aroundan outside roll 39, as shown in Figure 1. The stretcher roll 40a is positioned between the forming part and the press roll assembly 30 instead of between the press roll assembly 30 and the drying section as shown in Figure 1.

In place of the horizontal press roll assembly l6, however, three sets of vertical suction presses 50, 5i and 52 are provided and each are equipped with separate felts 53, 54 and 55. v

The first suction press 50 is composed of a suction roll 56 having a suction head 51 therein and a drip pan 58 therearound. A rubber-covered top roll 59 cooperates with the suction roll '56 at the suction area thereof to define a suction nip. A doctor 60 is provided for wiping the rubber surface of the top roll 59.

The felt 53 is trained over a guide roll 6i, through the nip of the suction press 50 and around a second guide roll 62. The guide rolls 6| and 62 are mounted at a level slightly below the top of the roll 56 so that the felt will cover the entire suction area provided by the head 51. After passage around the roll 62, the felt 53 is directed around the stretcher roll 63 and thence upwardly in front of another guide roll 64 for recontacting the web W from the forming wire Ill; The wire side of the web W engages the felt and the felt conveys the web through the suction nip of the first vertical suction press 59. After passing through the suction nip; the web W is immediately separated from the felt 53 and directed over a guideroll 65 into contact with the second felt 54 of the second suction press assembly 5| The felt 54, is trained around guide rolls 66 and 61 positioned at a level below the top of the suction roll 68 of the second suction press 5! so that the felt will only engage the web at the suction nip' provided by the suctionhead 69 and so that the felt will cover the suction-area' A drip pan I0 surrounds the suction roll 68 to protect the felt 54.

The felt at is trained under a stretcher roll i2 and in front of a guide roll I3 in the same manner as the felt 63.

After passage through the suction nip of the second press 5|, the web is guided over a guide roll I4 and through the suction nip of the third suction press 52. The press 62 is composed of a suction roll I5 having a suction head I6, and a top press roll 11 preferably Stonite-covered. A drip pan I8 surrounds the suction roll I5 to protect the felt 55.

The felt 55 has a somewhat different run than the felts 53 and 54. As shown, the felt is trained over a guide roll I9, thence through the suction nipof the press 52 where it contacts the web W. The guide roll then receives the felt therearound. This guide roll is positioned under the guide roll 29 for the felt 34. After passage around the guide roll 86 the felt 55 is passed rearwardly over another guide roll 8| and thence downwardly around a stretcher roll 82. After passage around the stretcher roll the felt is guided upwardly in front of the guide roll 83 and thence around the roll I9.

After passage through the nip of the suction press 52 the web W is momentarily removed from the felt 55 and directed over a guide roll 84 as shown. "The Web then recontacts the felt and is conveyed to the roll 29 from which it passes unsupported to the nip of the horizontal press 30. The felt 34 then covers the top side or non-wire side of the web W as it passes through the nip of the horizontal suction press 30.

In the modification shown in Figure 3, therefore, three vertical suction presses 50, 5| and 52 covered plain bottom rolls 68a and 15a. The felt 54 for the press 5la is guided around a. roll 66a similar to the roll 66 but at a higher level than the roll 66 so that the felt will contact the web W before it reaches the nip of the press 5Ia. Likewise, the guide roll I9a for the felt 55 is similar to the guide I9 shown in Figure 3 but at a higher level than the roll I9 so that the felt will contact the web W to wrap the web around the roll 11 before it reaches the pressure nip. I

The horizontal press assembly 30a is similar to the press assembly 30a shown in Figure 2 and is composed of a rubber-covered plain roll am having a rubber cover 44 and a plain Stonite roll 32a. The guide roll 36 shown in Figure 3 can be eliminated and the web can be passed directly around the roll 32a to the guide roll 31 and thence around the drying cylinders 38.

Thus, in Figure ,4, a first vertical suction press is provided followed by two plain vertical presses havingru bber covered bottom rolls and Stonitecovered top rolls. The horizontal suction press 39 is replaced with a horizontal plain press 38.

In other modifications of the invention, the two presses 5la and 520. can be replaced with a single press or, as shown in Figure 5, a single vertical press can be used in advance of the horizontal press and another vertical press can be used after the horizontal press.

In Figure 5, parts identical with parts described in Figures 3 and 4 have been marked with the same reference numerals. As shown in Figure 5, the suction press 52 of Figure 3 receives the web W directly from the forming wire l instead of from the suction press 5| a shown in Figure 3. In addition, the plain vertical press 5la of Figure 4 is positioned after the plain horizontal press 30a instead of before the press as shown in Figure 4.

In the reverse press section of Figure 5, the wire side of the web is supported on the felt 55 and conveyed through the suction nip between the suction roll 15 and the rubber-covered top roll Tla of the first press 52. The web is then conveyed while still supported on the felt 55 to a point just under the guide roll 29 where the web is removed from the felt, trained around the guide roll and passed vertically upward into contact with the second or reverse ,felt 34 which engages the top side or non-wire side of the web.

through the plain nip between the Stonite roll 32a 3 and the rubber-covered roll 3 la of the plain press 30. After passage through the nip the web is guided over the top of the Stonite roll 32a into contact with the felt 54 which re-engages the wire side of the web and conveys the web through the plain press 5ia composed of the Stonite roll II and the rubber-covered roll 6811. After passage through the nip of the press Bla the web then travels over the guide 31 and around the drier drums 3 8.

It should be understood that numerou arrangements of vertical and horizontal press roll assemblies can be used, and that these assemblies can be equipped with plain metal rolls, Stonite covered rolls, rubber covered rolls, plain suction rolls, and rubber covered suction rolls.

In the reverse press sections of this invention the web is directlyreceived from its forming wire on an under felt engaging the wire side of the web and conveying the web through one or more pressure nips. Additional felts as shown in Figures 3 and 4 can be used to successively receive the wire side of the web.

The reverse press roll assembly includes horizontally aligned rolls that receive the web in an upward vertical direction through the nip therebetween while the web is covered with another felt engaging the top side or non-wire side thereof. Additional press roll assemblies can be mounted between the reverse press and the drier section of the machine.

The reverse press sections of thisv invention avoid the heretofore necessary long draws of unsupported web with the attendant stretching of the web. In all of the illustrated embodiments of the invention the unsupported web draws are quite short and .yet, at the same time, the web is supported almost continually from the time it leaves the forming wire until it passes through the last press. Unsupported web draws are reduced to a minimum.

The reverse press sections of this invention also avoid the necessity for completely changing the direction of travel of the web'in order that the top side or non-wire side of the web can be engaged with a felt while the wire side of the web can be subjected to direct action by a press roll.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principle of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention: 1

1. A reverse press section for mounting between the forming part and drier section of a paper making machine comprising a pair of horizontally aligned press rolls rotatably mounted adjacent the couch roll end of the forming part, a first looped felt trained over the first roll of the horizontally aligned rolls and downwardly through the nip provided by the rolls, a guide roll outside of the loop of said felt for directing the felt away from the second roll of said horizontally aligned rolls, a pair of guide rolls within the loop of said felt to form a short top run on said felt in spaced relation beyond said second roll of the horizontally aligned rolls, another guide roll between said second roll of said horizontally aligned rolls and said pair of guide rolls for maintaining the web out of contact with the felt, another guide roll within the loop of said felt for forming a short top run in advance of the first roll of said horizontally aligned rolls whereby a paper web from said forming part I will have the wire side thereof engaged by said felt for travel through said nip, around the second press roll out of contact with the felt and into re-engagement with said felt along said short run beyond the second press roll, a second pair of horizontally aligned rolls defining an upward passage pressure nip at a level above the short run beyond the second press roll of the first mentioned horizontal assembly, a guide roll for directing the web from said run upwardly through said second pressure nip, and a second looped felt trained through said nip for engaging the nonwire side of said web.

2. A reverse press section for location between the forming wire and drier section of a paper making machine comprising a pair of cooperating press rolls defining a pressure nip therebetween, a looped felt trained through said nip having a first run in advance of said nip and a sec- 0nd run beyond said nip, said felt runs being arranged for receiving thereon the wire side of a web of paper formed on the forming wire, said second run of the felt being downwardly inclined relative to the first run, a guide roll at a level above the second run of the felt for receiving the paper thereover as it passes from the press rolls to said second run, a pair of horizontally aligned press rolls adjacent said second run of the felt in overlapping relation to said second run, said pair of horizontally aligned rolls defining an upward passage vertical nip in closely spaced relation above said second run of the felt, a single second guide roll immediately adjacent said second run of the felt between said vertical nip and the second run of the felt for receiving therearound the non-wire side of a paper web from said second run to change the direction of travel of the web in a single turn for directing the web upwardly into the vertical nip. and a second felt trained through said vertical mp on the nonwire side of the web of paper to cover said nonwire side of the web as it passes through the vertical nip. whereby the web of paper only has a very short unsupported draw as it passes around the single second guide roll from the second run of the first mentioned felt to the secondv felt.

EARL E. BERRY.

Images