US2054391A - Multiple cylinder web drier - Google Patents

Description

Sept. 15, 1936. E. SCHMIDT MULTIPLE CYLINDER'WEB DRIER Filed July 25, 1955 Patented Sept. 15, 1936 PATENT OFFICE MULTIPLE crmnnna wan DRIER Ernst Schmidt, Unter-Polaun, Czechoslovakia Application July 25, 1935, Serial No. 33,181 In Germany July 23, 1934 carried out in paper making machines of usual design in such a way that the paper web, on' leav- 1 ing the presses with a moisture content of about 40 to 50 per cent, is led through a long series of drying cylinders arranged in subordinate groups, said cylinders being partly surrounded by an endless blanket of drying felt, for the purpose of is pressing the paper or the paper pulp against the heated surfaces of the cylinders. Such a set of drying cylinders forms in the structure of a paper making machine a basic arrangement defining the chief lines of the structural arrangement of such a machine owing to the greatnumber of drying drums'and' their driving means which have to be mounted in the frame. According to one known arrangement additional drying devices are included depending on the use of a drying felt which has to be brought back to a dry state by heating both on its upper and lower faces, in 'which arrangement also it is necessary to arrange scrapers on the unwrapped peripheral surface of the drying cylinders. In order to render unnecessary the provision of a over the whole width of has been suggested to effect the drying by means of a stationary system of heating pipes replacing the revolving drying cylinders. This is achieved by conducting the web of paperpulp to be dried 'over drums rotating independently in the neighbourhood of of'narrow feeding felt strips, to prevent direct contact of the material with 40 the heating surface of the pipe. Such an arrange-. ment is not well adapted to the drying of paper pulp with reduction of the drying temperature on the surface of the drum, and its adaptation tothe drying mechanism of an existing paper making machine would involve an entire structural transformation of the machine by eliminating drying cylinders.

According to my present invention as distino guished from previously known arrangements the drying equipment is arranged so that it may be used in an'existingpaper'making machine without the use of drying felts and retaining substantially the arrangementof' drying cylinders usual in paper making machines. The invention consistsin that each of the-revolving drying cylinders is surrounded by a strainer perforated jacket wall spaced a small distance from the cylinder body, and that, at th flines of engage- 0 ment and departure of the paper pulp web, spring drying felt extendingthe paper pulp web it the heating pipes with the assistance care being taken pressed guide cylinders or rollers are provided which may replace the usual guide rollers conducting the drying felt to the cylinders. The increase in cylinder diameter involved by provid-' ing perforated jackets may be also adapted to the line of contact with the guide rollers. Further the annular space between the perforated jacket wall and the body of the drying cylinder is used for the purpose of exchanging the drying air and for the removal and/or storage of the wet steam, said purposes being achieved by blowing dry, warm air through adiustable air nozzles directed towards the perforated jacket wall in the region of the free circumferential portion lying between the guide rolls. 1 Narrow guide strips are preferably arranged as accessories at the non-perforated margins of the cylinders to render possible, if necessary, the setting of a paper web on the cylinders. Said guide strips are kept in movement owing to the rotation of the drum and are shiftable in axial direction by means of an engaging and disengaging device.

A- part of a drying plant or section according .to the invention is illustrated in Fig. lin sectional elevation. Fig. 2 shows a side view partly in section. 3

Fig. 3 is a side view showing the spring pressed roller.

A drying cylinder l heated in known manner is provided with a finely perforated jacket wall 2, e. g. made from copper, said wall being spaced at a distance from the body of the drying cylinder, whereby the heat operates on the'paper pulp web 3 not as hitherto by conduction, but by radiation. The jacket wall 2 is connected by flanges 4 to the body ofthe drying cylinder, so that'between said cylinder body and the wall an annular space 5 closed at its ends results from which the generated steam may escape through the perforation of the said wall 2. The paper pulp web is conducted round the jacket wall 2 in a manner known in drying devices and is held thereon with a slight spring pressure by means of rotatably mounted guide rollers 6.

Near the part of the wall 2 not wrapped by the paper web-pipes with nozzles I are arranged transversely to the paper web through which warm, dry air is blown into the annular space 5.

By such an arrangement of the drying means or section according to the invention, all defects accompanying the previous employment of the drying felts and scrapers are removed. There is no need to apprehend sticking or burning of the paper pulp web on the jacket wall 2 heated by 'radiation only, with all inherent disadvantageous results affecting the quality of the paper and, an i-ndisturbed working. This is also assisted by warm air being blown into the annular'space iwhlchensuresaneasyremcval of .00

2 the paper pulp web from the wall 2, so that the latter may be cleaned if need arises by a simple brushing. v

The warm air blown by means of the nozzles I into the annular space 5 also-provides a control of the heating action exerted by the drying cylinders and thereby permits higher velocities of the paper making machines simultaneously with the highest quality of paper. The air blown into the annular space 5 effects not only a supplementary drying action by'supplying heat but it assists drying also by quickly carrying away from said annular space .5 any water vapor formed therein, so that in said space there is a practically uninterrupted presence of dry air' capable of absorbing vapor. The arrows in Fig. 1 indicate the admission of the warm air to the jacket space and the discharge of warm air and water vapor therefrom.

The consumption of-heat energy in the drying section or plant arranged according to the invention is essentially lower, because there is no carrying 011 of moisture'stored by drying felts,

these having been eliminated.

In order to allow the paper web to be arranged on the jacket wall 2 at the beginning of the work, or to provide against tearing of the edge of the paper web, narrow guidestrips 8 may be provided. These strips are moved by the rotating cylinders and if required they may be shifted endwise into the range of the width of the paperweb by means of shifter devices 9.

The jacket wall 2 is advantageouslysupported by annular spacing members ill, provided with apertures parallel to the axis of the cylinder.

A spring pressed roller is illustrated in Fig.

I 3 of the drawing. The roller 8 beam with its roller 5 may be regulated.

cylinder.

axle or shaft in sliding like blocks I! which are held between helical springs I'I-and It. The

spring I8 is located between the base of a standard I! attached to the framework ll of the cylinder and the block I, whereas the helical spring I I is located between the block II and a slider l9 slidably mounted similar to the block I5 between the legs II of the standard It: The free ends of the legs. I: are connected by a bridge I! having a boring the wall of which-is provided with screwing seat. Through this latter passes'a screw bolt "the inner ends of which act upon the slider It, so as to move the latter inwardly between the legs II or in a reverse direction. In this waythe pressing action of the For more easily removing the roller from the cylinder the slider it bears a rotatable hook' like; member II the hook like end of which'may be swung in to embrace the shaft I! of the roller,

so that by turning the screw, bolt in required direction the roller 6 is lifted from the What I claim is:

' 1. Feltlessdrying cylinder equipment for drying the web in paper making machines compris ing for each drying cylinder a perforated jacket wall spaced from and surrounding the body of the cylinder, spring pressed guide means provided at the lines of engagement and departure ofthe paper pulp web with and from said wall, and air supplying means arrangedbetween said guide means forblowing dry warm air'into the annular s'paeebetween said jacket wall and cylnder body.

2. Feltless drying cylinder equipment for drying the web in paper making machines comprising for each drying cylinder a perforated jacket wall spaced from and surrounding the body of the cylinder, spring pressed guide rollers provided at the lines of engagement and departure of the paper pulp web with and from said wall, and air supplying nozzles between said guide rollers for flowing. dry, warm air into the annular jacket space.

3. Feltless drying cylinder equipment for dry-.

ing the web in paper making machines comprising for each drying cylinder a perforated jacket wall spaced from and surrounding the body of the cylinder, spring pressed guide means provided at the lines of engagement and departure of the paper pulp web with and from said wall, air supplying means between said' guide means strip adapted to lap around the ends of the guide rollers and jacketed cylinder uncovered by the web, and means for shifting said strip axially of said rollersand cylinder.

" 5. Feltless drying cylinder equipment for drying the web in paper making machines comprising a revolving drying cylinder having' a perforated jacket wall spaced from and surrounding the body of the cylinder, spring pressed guide means provided at the lines of engagement and departure of the paper pulp web with and from said wall, air supplying means arranged between said guide means for blowing dry, warm air into the jacket space, perforated distance pieces between the cylinder body and the jacket wall, an

endless running guide strip adapted to lap around the ends of the guide rollers and jacketed cylinderuncovered'by the web, andmeans for'shifting said guiding strip axially of said rolls and cylinder.

6. Feltless dryingcylinder equipment for drying the web in paper making machines comprising a revolving drying cylinder having a perforated jacket wall spaced from and surrounding the body of the cylinder, spring pressed 'guide rollers provided at the lines of engagement and departure of the-paper pulp web with and from said wall, air supplying nozzles arranged between said guide rollers for blowing dry warm air into the jacket space, perforated annular distance pieces between the cylinderbody and thejacket wall, an endless running guide strip adapted to lap around the ends of the guide rollers and jacketed cylinder uncovered by the web, and means for shifting the guide strip axially of said rolls and cylinder.

7.-'1 eltless drying cylinder equipment according to 'claim 1, in which "the air supplying means is adjustable.

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