US1573469A - Method of regulating the operation of paper-making machines - Google Patents

Description

Feb. 16,, 1926. 1,573,469

. E. J. WILSON ET AL METHOD OF REGULATING THE OPERATION OF PAPER MAKING MACHINES Filed April 28, 1925 Patented Feb. 16,1926.

UNITED STATES PATE EZEKIEL .1. WILSON, or EAST GREENBUSHQAND EDWIN A. nEEs', or ALBANY, NEw' NT OFFICE.

' YORK, ASSIGNORS TO I. C. HUYCK & SONS, OF RENSSELAER,NEW YORK, A'COR- IPOBATION OF NEW YORK.

METHOD OF REGULA'I'IN G THEOPERATION OF PAPER-MAKING HAQHINES.

Application filed April as To all whom it may concern:

Be it known that we,EzEKrEL J. WILSON and EDWIN A. REES, citizens of the United States, residing at EastfGreenbush, in the 5 county of Rensselaer, and Albany, in the count ofAlbany, respectively,and State of New ork, have invented certain new and useful Improvements in Methods of Regulating the Operation of Paper-Making Machines and We do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable those. skilled in .the art to which it appertains to make and use the same.

The invention relates to paper manufacture and more particularly to a method by which excessive stresses on the felts of paper making machines may besdetermined and eliminated, and the efficiency of the machine as well as the efiiciency and life of such felts increased.

While the invention is of more general app1ication,'it may be utilized with particul lar advantage in connection with cylinder or paperboard machines, wherein the stress put upon the felts is usually heavy and varies widely at different points in its travel due to thetnumber of cylinders and press rolls driven thereby.

In cylinder or paper board machines, the felts not-only cooperate with the cylinder molds and couch rolls and with the press rolls in forming and partially drying the sheet of paper stock, but also serve totransmit motion ,from the power driven press rolls to the cylinders and couch rolls and to the other press rolls. The pull or stress on the felt therefore, increases as the felt passes betweenand drives successive cylinders and. couch rolls and successive-pairs of press rolls, is or should be the maximum at the point where the felt leaves the last pair of press rolls'driven thereby, and is released as' the felt emerges from between the power driven press rolls and returns to the first cylinder and couch roll. 'Thepull or stress thereon causes a strain or stretch of the felt and upon the release of the stress theelasticity of the felt causes it toreturn to its normal length. There is therefore a repeated. stretching and ontractin of the felt during operation 0 the. mac ine which tends to gradually break down the felted 1925. Serial No. 26,391

more and more each day, thus destroying its efficiency and eventually requiring its replacement by a new felt.

It becomes important, therefore, that the stress and strains to which the felts are subjected at different points in their travel be determined and that the machine and its different mechanisms be regulated or adjusted to properly distribute the stresses on the felts and thus eliminate any excessive stress indicated and to reduce as far as possible the maximum stress tendin to im air the efficiency and shorten the life of t e felts, The present invention provides a method for securing this result, and also a'method which enables a given machine to be equipped with felts which are best suitedfor long efficient operation under the proper conditions of use in such machine.

In accordance with the present invention,

the strain, stretch or elongation of the felt at different points in its travel is determined by measuring the length of the entire felt or of a predetermined portion thereof passingv these points. This may be done conveniently by any suitable form of'measuring wheel placed in engagement with the felt to indicate the length passing the point of engagement. By thus measuring the stretch ofthe.

felt at different points, the point or points of greatest stretch and therefore of greatest stress or pull may be determined, as well as the comparative stress or pull between shecessive points in the travel of the felt. The

'OCCIIIIBIICG Of an GXC GSSlVE 01' undue stretch indicating an excessive stress or pull at any point or points in the travel of the felt may the. felt, but also increases the efficiency of gthe machine and permissible speed of operation.

The determination of the maximum bonds and to cause the felt to stretch out Estretch of the felt under efficient operating repeated stretching and contraction indi-v cated may thus be avoided or discontinued and felts selected 'andused which are best suitedffor use under the indicated conditions. i

i The invention'will be further explained in connection with its application to a paper board machine of the type illustrated dia-v grammatically in the drawings in which Figure 1 is a diagram showing the paths of travel of the felts through the macl-une, and Figure 2 is a planwiew of a suitable form of instrument for measuring the length of the felt the desired points.

The machine illustrated in Figure 1 comprises a lower felt 4 driven from the .lower 'roll 6 of, the last pair of press rolls and passing overa series of idler and tension rolls 8 and 10 and over a plurality of cylinder molds 12, each of which-is arranged to rotate in a vat 14 and each of which cooperates with a'couch roll 16 pressing against the upper side of the felt. As is usual in this type of machine, the vats contain paper stock whichis carried by the successive.

molds onto the under side of the felt. From passes over a roll 18 and between a pair'of guide rolls 20 where it meets with the upper felt 22 which is driven from the upper roll 24 of the last pair of press rolls and passes over a series of idler and tension rolls, as shown in Fig. i. I The two felts between which the paper stock is carried pass together. between the series of pairs of press rolls 26 in v the usual manner and thence around the press rolls 6 and 24, the sheet of paper stock passing out from between the felts and to the drier which may be of any usual form. The press rolls' 6 and 2 1 of the last press are driven by any suitable gearing connection fromya driving pulley 28. The last press rolls are usually the only ones of the machine which are driven from an external source, the felts themselves constituting the driving means for the cylinder molds and couch rolls and for .the press rolls.

Considering, for example, the lower felt 4, it will be seen that in its traverse through the various parts of the machine, it is subjected-to a progressively increasing tension or pull which is a minimum between the driving roll 6 and the first cylinder mold and whichincreases in value foreach'cylinder and couch roll and for each pair of .presser rolls through which the felt. passes and which reaches a maximum at a point between'the las pair at; ill-1W press rolls 26 and the driving press rolls 6, 24. This in'-.

creasing tension or stress gives rise to a correspondingly increasing stretch, strain or elongation in the felt. The upper felt 22 undergoes a similar variation in tension extent to which the felt is stretched at this point as compared to its normal length, the wheel 30 is placed upon the felt at the point at whichthe measurement is to be made and is maintained in contacttherewith while the .felt is making one complete revolution 'or while a portion between two fixed points on the felt travels past the wheel. While a selected portion of the felt only may be measured, it will usually be found to be more convenient to measure the length of the entire felt travelling past the point or points at which measurement is made.

As already indicated, the length of the travellingfelt may be measured after it has passed each cylinder and couch roll and after it has passed each pair of press rolls, and thus the stretch of the felt due to its operathe last cylinder and couch roll, the felt.

tion of each of the devices may be determined as well as the maximum stretch to which it is subjected and theextent to which it stretches and contracts during each revolution or complete trayel through the machine! Improper adjustment or regulation of any of the mold cylinders and couch rolls of any of the pairs of press rolls may be thus detected and the proper adjustment or regulation'madeto secure the proper and eflicient operation of the various mechanisms and the proper distribution ofthe stresseson the. I

felt. The maximum stressto which the felt should be subjected under proper working conditions may also "be determined as already 1 indicated and the use of felts which are ill adapted for withstandingsuch stresses may be avoided. The continued operation of the machineunder conditions which .put an abnormal and unnecessary pull or stress upon the felt and which could not otherwise be detected, may also be avoided by measuring cable to paper board machines, itis not to be considered as limited in its a plication to such machines but may be app ied with ad. vantage to'the duos i the stresses and strains in felts of other machines or mechanisms or in analogous travelling Webs which are subject to varying tensions throughout their course of travel.

\Vhat is claimed is:

'1. A method of regulating the operation of paper making machines provided with endless felts which drive one or more devices thereof, which consist in determining the stresses or strains in the travelling felt by measuring the length of a. predetermined portion of the felt passing a selected point .or points, and adjusting the machine to eliminate abnormal stresses or strains indicated.

the length of a predetermined portion of the felt at successive points in its travel to determine the stretch of the felt at such points,

and regulating the devices driven by the felt to eliminate abnormal stretch indicated at any point.

3. A method of determining stresses 01' strains in the travelling felt of a paper making machine or analogous travelling web subjected to varying degrees of tension which consists in measuring at one or more points in its travel the length of a predetermined portion of the felt as compared with the length of such portion free of tenslon.

4. The method of determining the stress on the travelling felt of a paper making machine at a selected point in its travel which consists in measuring the length of a predetermined portion of the felt passing that point as comparedwith the normal length 40 of said portion.

EZEKIEL J. WILSON. EDWIN A. REES.

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