US3283415A

US3283415A - Paper drying apparatus

Info

Publication number: US3283415A
Application number: US359682A
Authority: US
Inventors: Auxilius P Schnyder
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-04-14
Filing date: 1964-04-14
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08

Description

1955 A. P. SCHNYDER 3,

PAPER DRYING APPARATUS Filed April 14, 1964 2 Sheets-Sheet 1 FIG. 1

INVENTOR. AUX IL\ US P. SCHNYDER BY MMIQWA W 75 104 6 Eda/n4.-

ATTORNEYS Nov. 8, 1966 A. P. SCHNYDER 3,283,415

PAPER DRYING APPARATUS Filed April 14, 1964 2 Sheets-sheet 2 my, I In INVENTOR. AUXILIUS P. SCHNYDER BY mmg 771 1 4 W dda/VKL ATTOR N EYS United States Patent 0 3,283,415 PAPER DRYING APPARATUS Auxilius P. Schnyder, 146 Cherry Lane, Teaneck, NJ. Filed Apr. 14, 1964, Ser. No. 359,682 2 Claims. (Cl. 34-111) This application is a continuation-in-part of my prior application Serial No. 262,544, filed March 4, 1963, now abandoned.

This invention relates to paper drying apparatus of the type having drying cylinders provided with dryer felt for absorbing moisture from the paper, and provides an improved means to vaporize the moisture in the felt and in the paper, and to remove the moisture from the area of vaporization.

It is customary to dry paper by passing it continuously and at a uniform rate over a multiplicity of heated drying cylinders consisting of upper cylinders mounted in a horizontal plane and lower cylinders also mounted in a horizontal plane. The drying apparatus may be described as including a succession of three cylinder units the axes of which form a triangle, one unit having two cylinders below and one cylinder above and the adjacent unit having one cylinder below and two cylinders above.

The web of paper undergoing drying is passed continuously from one heated cylinder to another and two endless dryer felts are employed in the apparatus, one travels over the paper while it is in contact with each upper cylinder and the other passes over the paper while it is in contact with each lower cylinder. Between each adjacent pair of lower cylinders and each adjacent pair of upper cylinders, a roller is mounted to direct the dryer felt over a substantial area of the paper which is in contact with the cylinders. The paper passes over a lower cylinder, upward over the upper cylinder and downward over the other lower cylinder. An endless web or belt of porous dryer felt which is in contact with the paper on each cylinder absorbs moisture from the paper. It is customary to return the endless webs of dryer felt along direction and tension rollers. Means are usually employed to heat this returning section of the felt web to evaporate the moisture. Duct means have been suggested heretofore for removing moisture vapor from the area of the drying rollers. Perforate felt drying rollers have also been suggested for use between the drying rollers over which the dryer felt passes together with means to suck moisture out of the felt.

This invention provides a duct system for forcing air, preferably dry hot air, into and across new open grillage drying rollers and through the pores or fibers of the overlying dryer felt, and also an exhaust duct system for removing moisture laden air from the felt. The exhaust duct system is preferably constructed and arranged to remove water vapor from an area between the drying cylinders which is evaporated from the surface of the paper, particularly from the free runs of paper passing from one cylinder to the next, and also includes selective provisions which prevent paper being accidentally sucked into the duct system.

The apparatus of the invention comprises a manifold extending along each open grillage roller for forcing hot air into and across the open grillage roller and through the felt overlying the open grillage roller, and an exhaust duct means located along and over the outside of each open grillage roller so as to receive the moisture laden air forced through the felt and sweeping the surface of the paper, and carry it under reduced pressure to an outside vent. There is an appreciable amount of water evaporated directly from the paper and the exhaust duct system is constructed and arranged to remove this additional Ice water vapor from the area between the two adjacent runs of paper passing from one cylinder to the next cylinder.

Preferably, the apparatus comprises a cap or hood extending lengthwise of each open grillage roller for forcing vhot unsaturated drying air through the dryer felt transversely either uniformly or at different controlled rates over the segmental portions making up the entire width of the felt web, and a vapor collecting duct means extending the full width of the open grillage rollers and drying cylinders connected to an exhaust air system operated under reduced pressure which removes the moisture laden air transversely over the entire width of the web of paper. The means of adjusting the rate of air sectionally across the width of the system will make it possible to compensate for any lack of uniformity of absorbing the moisture laden air into the exhaust duct.

The apparatus of the invention effects a more rapid and efficient drying of the paper with a reduced volume of drying air, uniform drying over the width of the paper web, and better control. The drying apparatus can be adjusted to obtain a uniform moisture profile at the exit end, and the protection of the paper from entrained lint and surface dirt.

Each exhaust duct is shaped to divide the air in accordance with the relative needs as the air enters through the felt into the vapor space formed by the free spaces of paper between upper and lower drying cylinders, and between the one paper drying cylinder and the felt covered open grillage roller, one above the other, with the exhaust duct being placed in this vapor space. The major portion of the air is directed toward the oncoming web of paper with its hotter side having broken contact with the heated drying cylinder being exposed so that the air will sweep this side clear of the film of water vapor before being sucked into the exhaust duct. The lesser portion of air is directed to sweep the colder side of the Web of paper leaving the processing dryer, and is then sucked into the exhaust duct through open slots on the opposite side of the duct. Both slots extend the full width of the duct. The slots have an open mesh wire covering to prevent occasional shreds of paper from being sucked into the duct and clog the entire exhaust duct system.

The exhaust duct being rigidly framed for spacing the full width of the machine without deflecting serves to support the doctor blade with built-in adjustments for contacting the drying cylinder or backing off.

These and other novel features of the invention will be better understood after considering the following discussion and accompanying drawings in which FIG. 1 is a vertical end view of one unit of paper drying apparatus embodying the invention;

FIG. 2 is a sectional view of a modification of the apparatus of FIG. 1;

FIG. 3 is a longitudinal side view of a felt drying apparatus of the invention;

FIG. 4 is an enlarged view, partly in section, of the left end portion of FIG. 3, and FIFIG. 5 is an enlarged sectional view taken at 55 of It is understood that a complete paper drying apparatus comprises several upper drying cylinders 1 arranged in a horizontal plane and several lower drying cylinders 2 also arranged in a horizontal plane, and that there is a continuous upper drying felt 3 which passes over the paper on the upper cylinders and a continuous lower drying felt 4 which passes over the paper on the lower cylinders. The felt is made of a porous moisture absorbing material and means are provided to maintain proper tension on the drying felts, all well known in the art. For convenience in describing and claiming the invention, the upper cylinder and the two lower cylinders have been 1 called a unit.

, drying apparatus.

There are repeating similar units comprising the complete apparatus.

The web of paper 5 passes continuously over the cylinders which are usually heated, as indicated by the arrows and the upper drying felt 3 passes with the paper on the upper cylinder absorbing moisture from the paper and the lower drying felt 4 passes with the paper on the lower cylinders 2 absorbing moisture from the opposite side of the paper. The open grillage rollers 6 and 7 for the upper cylinders and the open grillage rollers 8 for the lower cylinders are located as is usual in this art so as to provide a large peripheral area of contact of the drying felts with the paper on the cylinders. As best shown in FIGS. 3, 4 and 5, each open grillage roller has end shafts 10 and 11 mounted in bearings Hand 13 which are attached to

side portions

14 and 15 of the The shafts are secured to

hubs

16 and 17 to which a plurality of spacer ribs 18 are secured. These ribs have relatively wide bearing surfaces 19 and shanks 20 by means of which they are secured to spacer support rings 22. The entire open grillage roller is machined to a high degree of uniformity and the exterior surfaces 19 are smooth to prevent injury to the felt.

The means for forcing dry hot air into the open grillage roller and through the felt comprises a hood 23 supported below the open grillage roller 8 as shown in FIGS. 1 and 2. The hot air is supplied to the hood through the duct 24. The hood has

end closures

25 and 26 which bear against

rings

27 and 28 on the hubs to prevent a loss of air transversely. As best shown in FIGS. 2 and 5,

the

longitudinal edges

31 and 32 of the hood are bent for fitting concentrically with the open grillage roller, with a safe minimum clearance between the hood and .the roller, and with a sufficient gap between the edges of the hood and the drying felt to prevent wear and tear of either, as is probable with actual contact between the two. The escapement of hot drying air through the gap between felt and hood is minimized by the bent edge .of the hood which deflects the air toward the felt, so

that substantially all of the air is forced into and through the porous felt. The moisture exhaust conduit 35 of the invention is mounted over and extends the length of the open grillage rollers and is supported at its ends by

brackets

36 and 37 attached to the

machine support frames

14 and 15. The brackets are connected to duct 38 which leads to a low pressure system operated by an exhaust fan (not shown). The exhaust conduit comprises a duct 40 having wide slots 41 and 42 which may have perforations or be covered with

wire mesh

43 and 44 extending the entirelength of the duct. These screened or perforated openings are located so as to remove the moisture laden air from the dryerfelt and also the moisture evapcrating from the free runs of the paper passing from one cylinder to another. The exhaust conduit not only carries away the moisture laden air from the drying felt and the free runs of the paper but it tends to reduce the pressure in the surrounding area which increases the evaporation rate.

The duct 35 is preferably shaped as shown in crosssection to form a depending baffle or deflector nose 46 'which directs the major part of the air towards the left sibility of shreds of paper during start-up and occasional breaks being sucked into the duct with the possibility that such shreds of paper might clog the duct or the following system entirely.

The apparatus illustrated in FIG. 2 provides a pivotal support for doctor blade 47, which can be made to contact the surface of the upper cylinder 1, or can be retracted to leave a gap between the blade and the cylinder. The doctor blade 47 removes. lint and pulp fibers from the cylinder which are carried away by theexhaust conduit or scrapes off paper while it is threaded into the machine. or sticks to the surface of the cylinder due to a snap off, the paper being transferred into the following nip between the drying cylinder and felt.

I claim: a

1. In paper drying apparatus having a multiplicity of cylinder units consisting of one upper cylinder, two lower cylinders in a triangular spaced relation with the upper cylinder and with means for passing paper over the cylinders and drying felt over the paper on the cylinders, two open grillage felt drying rollers one on each side of the upper cylinder and an open grillage felt drying roller between the two lower cylinders, the improvement which comprises a hood extending lengthwise of each open grillage roller provided with means to force hot air through the open grillage roller and the overlying felt, an exhaust conduit supported in the space between the two lower cylinders and the upper cylinder and extending lengthwise thereof, said conduit having an opening extending lengthwise for the transverse entry of moisture laden air from the drying feltand moisture laden air from between the adjacent runs of paper web passing adjacent the exhaust conduit, said openingsbeing of a size to prevent shreds of paper being sucked into the conduit,

a removable doctor blade bearing on the upper cylinder for scraping off lint and fibers: which are removed by the exhaust conduit, and means to operate the exhaust conduit under reduced pressure.

2. In paper drying apparatus having amultiplicity of cylinder units consisting of one upper cylinder, twolower cylinders in atriangular spaced relation with the upper cylinder and with means for passing paper over. the cylinders and drying felt over the paper on the cylinders, two open grillage feltdrying rollers one .on each side .of the upper. cylinder. and an open grillage felt drying roller between the two lower cylinders, the improvement which comprises a hood extending lengthwise of each open grillage roller provided with means to force hot air through the open grillage roller and the overlying felt, an exhaust conduit extending lengthwise of each open grillage roller for removing vapor laden air over the width of the open grillage roller, said conduit having a .per-

forated surface which permits entry of lint and fibers but erate the exhaust conduit under reduced pressure.

References Cited by the Examiner FOREIGN PATENTS 3/1937 Great Britain. 3/1941 Great Britain.

JAMES w. WESTHAVER, Primary Examiner.

Claims

1. IN PAPER DRYING APPARTUS HAVING A MULTIPLICITY OF CYLINDER UNITS CONSISTING OF ONE UPPER CYLINDER, TWO LOWER CYLINDERS IN A TRIANGULAR SPACED RELATION WITH THE UPPER CYLINDER AND WITH MEANS FOR PASSING PAPER OVER THE CYLINDERS AND DRYING FELT OVER THE PAPER ON THE CYLINDERS, TWO OPEN GRILLAGE FELT DRYING ROLLERS ONE ON EACH SIDE OF THE UPPER CYLINDER AND AN OPEN GRILLAGE FELT DRYING ROLLER BETWEEN THE TWO LOWER CYLINDERS, THE IMPROVEMENT WHICH COMPRISES A HOOD EXTENDING LENGTHWISE OF EACH OPEN GRILLAGE ROLLER PROVIDED WITH MEANS TO FORCE HOT AIR THROUGH THE OPEN GRILLAGE ROLLER AND THE OVERLYING FELT, AN EXHAUST CONDUIT SUPPORTED IN THE SPACE BETWEEN THE TWO LOWER CYLINDERS AND THE UPPER CYLINDER AND EXTENDING LENGTHWISE THEREOF, SAID CONDUIT HAVING AN OPENING EXTENDING LENGTHWIDE FOR TRANSVERSE ENTRY OF MOISTURE LADEN AIR FROM THE DRYING FELT AND MOISTURE LADEN AIR FROM BETWEEN THE ADJACENT RUNS OF PAPER WEB PASSING ADJACENT THE EXHAUST CONDUIT, SAID OPENINGS BEING OF A SIZE TO PREVENT SHREDS OF PAPER BEING SUCKED INTO THE CONDUIT, A REMOVABLE DOCTOR BLADE BEARING ON THE UPPER CYLINDER FOR SCRAPING OFF LINT AND FIBERS WHICH ARE REMOVED BY THE EXHAUST CONDUIT, AND MEANS TO OPERATE THE EXHAUST CONDUIT UNDER REDUCED PRESSURE.