US2977686A - Apparatus for the manufacture of paper - Google Patents

Description

April 4, 1961 A. G. STOUT APPARATUS FOR THE MANUFACTURE OF PAPER 5 Sheets-Sheet 1 Filed Feb. 19, 1959 April 4, 1961 A. G STOUT APPARATUS FOR THE MANUFACTURE OF PAPER 5 Sheets-Sheet 2 Filed Feb. 19, 1959 April 4, 1961 A. G. STOUT APPARATUS FOR THE MANUFACTURE OF PAPER 5 Sheets-Sheet 3 NQMM n I I I I l l lJllLl-l-l ll l Filed Feb. 19, 1959 April 4, 1961 A. G. STOUT APPARATUS FOR THE MANUFACTURE OF PAPER 5 Sheets-Sheet 4 iizvc/ziar jj/iwfi ga mm IW JG;

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: parts the I 2,971,686 a "APPARATUS FOR THE MANUFACTURE" or PAPER Arthur G.Stout, Lincolnwood, 111., assignor to Jamar- Dlmen Company, MelrosePiuk, 111., a corporation of Illinois V The present invention relatesgenerally to an apparatus for the manufacture of paper but relates moreqparticularlyto the drying aspects thereof.

; Inthe paper-manufacturing industry it is the conventional practice to form from the pulp stock a sheet or continuous web of materiahfl The conventional papermaking machine comprises a drying section provided with Patented Ap r. 4, 1961 web, passing through the drier section at high speed,

A breaks, and'hencerequires instantaneous attention by the sociated equipmentin order to permit the operator to prevent damage to the machine.

At times it is necessary to remove some of the doors for repair work or for removing all of the doors and aspowerful vacuum and to provide an efiicient condenser a large number of internally heated drying rolls, the purpose of which-is to dry or evaporate the excessmoisture from the 'web to a'predet ermined minimurn content. In a modern high-speed paper-making machine it is necessary to evaporate thousands of poundsof water per minwe in the form of water vapor and to conduct the same away from the immediate vicinity of the drying section.

In order. better to control thefair conditions immediately surrounding the drying section, it. has for. many years been the practice to provide a canopy type hood which partially surrounds the drying section. This type hood comprises a roof and side, and end" walls which depend therefrom, thus enclosing. thehprier pa'rtofthe drying section but leaving the lower part'ope'n. It has also been the practice to provide suitable fans to exhaust thewater vapor and lairmixture' and to discharge it to the outside atmosphere or to other process apparatuswhich will extract part of the heat. and water vaporpfor purposes of economy. Such constructions are. ofsome help in increasing eificiency but leave much to be desired. Ihere have also been, someinstallations wherein the drying section of the 'paper-niaking' 'machine has been fully enclosed; that is to say, such-hoods comprise a roof panel together with side auswhien reach rromthe' rooi In order to permit access to the drier section, especially firom the op'erativexside toffthe machine, some constructions have provided vertically movable doors closingsubstantially the -lower halfl'of th'efsi'deQ wall. 'Ihese doors, in operation, are horniallfloweredf and in'contact with themill floor, the doors having relatively small observa-; tion windows to permit the operator to observe the dry-,, ing sectionf When itis necessaryto haveaccessto'the drying rolls these doors must raised, ans forthis purpose it has been customary toprovideoperatingniechanism comprising cables, line shafts, electric motor-simmingnirechanismsin which the doors can slide, and'many other patts,together with cont-ro ls permitting the raising'.

' of, either one or more" doors or the entire. group of doors 5- Themanner in which the above and 'otherobjects' to, maintain a "vacuum within the hood closure.

One of the objects of the present invention is to provide apparatus for use in the manufacture of paper .for"

the purpose of dryingthfe paper and which, .while eflicient in' operation, will be of such construction that it can be produced, installed, and operated at relatively low cost,

and which will'enable the operator at all times to have.

full-and substantially unobstructedview of at least the lower part of the. operative part of the drier machine or of conventional paper-making machines.

Again itis an object of the invention to provide a novel apparatus for the control of the air temperature and humidity conditions surrounding the drier section of a" paper-making machine, which apparatus shall be simple in operation and effective in use.

A more specific object of the invention is to provide a closure for use with a paper-drying machine or section which will provide means for supplying the major portion cr me air for the drying operation to the drier section from one or more sources and to provide a relatively high velocity' air curtain on at least one side of the machine, the air curtain being blown across an opening between the mili-floorand the lower margin of at least one of the closures side walls, together with means'for exhausting from the upper interior portion of the closure all the air supplied to the closure, together with the-water-vapor resultingfrom the drying operation, and to maintain such balance in the space within the closure with that'of the mill area exterior of'the closure as to prevent more'than arelatively small amount of jair flowin'g from the millfinto' said closure through'the aircurtain.

fate the drying operation. A

quantityof air supplied to the closure is heated togfacili a attained will appear as the specification proceeds.

that formithej bottom clqsurelf or one side of the" drying Such a fully enclosed the partially enclosed ho'jod earlie conditionof the space within o d inay However, becausepf the number and complexity of the" i ty devices, there 1s always danger oithes ihitial, cost [is] relatively'high Furthermore, ql 'i l F F b 'ffi I ,:;The invention wi-llbe particularly described inconneo tion'with a typical drying section of a high-speed papermaking machine but this, it should be understood, is-by way of illustrationyand not by way 'of lirnitation sincel the invention may be used with advantage in other types- ,ofipaper-drying machines in ,themanufactureof paper."

"In the drawings: Y r

removal and v LA st'll further objector the invention 'l S fC I provide closure means of the kind described, wherein .thernajor.

figure; 1 is as diagra H 7 atio .view in perspective elevav p of that portionofthe closure strncturewhich extends oye th:'l1lill;1fl 00l, theisamebeing shown in its relation to; the drying section of a paper-making machine. i it Fig, 2, isia transverseaverticalsectional.view substam i tially on the, line zrazotfigrtbuton a somewhat largerscale and also showing part of the apparatus which is disposed in space underlying the mill floor.

Fig. 2A is a fragmentary transverse vertical section similar to the upper portion of the left-hand sideof Fig. 2 but illustratinga modified construction.

Fig. 3 is a transverse longitudinal section substantially on a line 3-3 of Fig. 2, viewed in the direction of the arrows but upon a smaller scale.

Fig. 4.is a view similar to Fig. 3 but taken along the line -44 of Fig. 2.

Fig. 5 is a fragmentary view on an enlarged scale of a part of the mill floor, a portion thereof being broken away to show one of the blower elements which is used tosupply high velocity air to discharge openings in the mill floor to constitute a substantially continuous air curtain extending across the open area below the bottom portion of one of the closure side walls and the mill floor."

Fig. 6 is a perspective view of a blower unit air trunk section, a number of which can be provided for supplying the high velocity air to constitute the substantially continuous air curtain.

Fig. 7 is a view in elevation substantially on the line 7-7 of Fig. 2, but on a smaller scale, showing a modified construction in which the air curtain arrangement is omitted from that side of the machine.

Fig. 8 is a fragmentary view of one end of a drying roll showing a modified feature, and

Fig. 9 is a view on the line 9--9 of Fig. 8.

General description of the invention There is involved a paper-drying machine which, in practice, is a section of a paper-making machine. The paper web, as it leaves the wet end of the paper-making machine, enters the drier section, there passing over a considerable number of hot rolls usually heated by steam admitted to the interior of the rolls. The dried web leaves the opposite end of the drier section in accordance with known practice.

The present invention in one form comprises a closure for the paper-drying section and includes a roof portion, end walls, and side walls which depend from the lower outer marginal portions of the roof portion, terminating at a level substantially above the mill floor, thus providing openings at each side of the machine extending substantially the entire length of the drying section.

This arrangement permits continuous observation of the drying machine. Passages are always available for the operator to gain instant access to the machine should conditions so require.

Means are provided to exhaust from the upper portion of the closure, as by power-driven and controlled exhaust fans, the large volumes of air which enter the closure for paper-drying purposes as well as the substantial volume of water vapor resulting from the dry ing operation.

"ln the illustrated form of the invention the drier section comprises a major portion which extends above the mill floor, and a minor portion located below the mill floor, there being an opening through the mill fioor over which the major portion of the drier section is positioried.

Below the mill floor there is provided blower means for supplying a major part of the air to the drier section together'with means for heating this air prior' to its passage through the mill floor opening, thereby increasing the drying capacity of the air. v

Asshown, the'said blower means is arranged to dis charge into what'may be termed a plenum chamber formed by two end wallsa'nd two side walls, th e latter extending the full distance between the end walls.- All of saidfwalls' extend from the underside of the'mill' floor textile nextmtieor below-or some other floor-like struc-' ture serving to close the bottom of the so-called plenum chamber.

Additionally, the invention comprises means for establishing and maintaining a substantially continuous air curtain located at each side of the drier section of the machine extending substantially the entire length thereof and flowing upwardly so as to traverse the opening between the lower marginal portions of the closure side walls and the mill floor.

In the form of the invention illustrated, the air curtain is provided by a plurality of motor-driven blowers connected to discharge high velocity air through a plurality of slots in or .adjacent the mill floor and extending longitudinally of the closure below the side walls of the closure. Means are provided whereby the air forming the air curtain is heated to aid in effecting the web-drying operation.

In the form shown the major part of the air for drying purposes flows through the opening in the mill floor and, while large in volume, is of relatively low velocity as compared with the air discharging from the slots to form the air curtain; that is to say, the air discharging from the slots to form the air curtain is of relatively high velocity and of relatively low volume as compared to that of the major air flow.

Means are also provided to control the volume of air and moisture vapor exhausted from the closure per unit of time, which is obviously related to the conditions within the closure, the same being dependent upon the speed of the web passing through the drier section, the amount of moisture in the web, the amount to be evaporated by the drier, etc.

Means are also provided for the control of the amount, volume, and velocity of the air supplied by the blower means which furnishes the major part of the air as well as that supplied to produce the air curtains.

The various means for supplying air to and removing it and the water vapor from the closure are operatively controlled to maintain such balance inwardly and outwardly of the closure as will prevent more than a relatively small volume of air from passing through the air curtains.

In a modified arrangement the closure is provided with an air curtain only on one side, the other side being closed from the roof portion to the mill floor and being provided with sliding doors to permit access to the drying machine.

There are further details and modifications but the foregoing general description will facilitate an understanding of the invention.

Further and more detailed description of the invention With particular reference to Figs. land 2, the closure comprises roof section 20. longitudinal side walls 21 and 22, and end wall portions 23 and 24, which parts are mounted over and preferably supported by steel framework S connected to and extending from the upper part of the machine frame F.

The drying machine shown is typical of the drying scction of a high-speed paper-making machine. It comprises The roof was 20 is substantially equa in length to that of the'machine and'is" greater'in width; thus pr'oviding' portions which extend beyond themachine at each side. The'side walls 21 and'22 are'substantiallycoextensive'in length with the met 20; and extend 'from" access by the operators to the and 6.

afo'imse r the roof, eaves, or side marginal portions downwardly to a plane substantially halfway between the roof, caves, and the mill floor, thus providing an elongated substan-' tially rectangular area extending from one end wall to the other 'end wall. This opening, as clearly appears in Fig. 1, provides an unobstructed view of the lower part of the drying machine and also provides for the'unobstructed l area closely adjacent the drier machine side frames. V The'structure thus described provides enclosure for the top and apartial closure for the sides of the machine, to gether with closures formed by the opposite end walls, which extend from the roof downwardly to the mill floor, except-for transverse openings necessary to permit entry and exit of the paper web to and from the drying machine. Communicating with the upper portion of the closure is a plurality of exhaust ducts 30, each connected with a motor operated exhaust fan 40 and serving as means for exhausting air'and vapors from the upper portion of the closure. .7 or V Since it is desirable thatthe major partof the airfor drying purposes be supplied to the closure under properly controlled conditions, means are provided for that purpose. 2 Means for supplying major part of air to machine closure The means, here shown for supplying the major part ofthe air for drying purposeswillbe best understood by reference to Figs. 2 and 3, wherein SF represents a sub-floor located a subtsantial distance below the mill floor M. Extending between the bottom side of the mill floor M and thesub-floor SF are four upright walls, i.e., two end walls 42 and 43'and two side walls 44 and 45, the latter extending from end wall to end wall (see Fig. 3.)'and thus forming, with the sub-floor SF, the mill floor M, and the opening 0 an open top chamber AC communicating with the drier section which extends above the Ashere shown, the side walls 44 and 45 are spaced outwardly of the vertical structural members 50 which support the drying machine. Since the drying machine is ormay be of conventional construction, parts thereof are shown" only'by broken lines which will suflice to indicate the relationship of the machine to theclosure and associated mechanism: 1 g

' In order to permit access to the chamber AC the side walls are provided withza plurality of doors 51.

1 Forsupplying a major part of the air for drying pur poses,'there'is'provided a pluralitly'of blowers 53,. each driven by aseparate electric inotor 54;

In order to provide heated air for discharge by thebloW- ers 53, aiheater 55 is provided and which communicates withthe blowerintake. By:.the described means .a large volume of'heated. air is supplied to; the chamber AC un derlyingthe mill floor and-tothat part of the drying ma- 6 which supply the air to the chamber, it is"obviou's the air discharging from the tubes 64, which are positioned to extend into the slots 60 in the millfloor, will also be heated. If desired, separate means can be provided to supply heated air to the ducts 61.

By making the ducts in sections, the air supply can be controlled individually to each section by means which will be described later. -'I hese'sections .alsofacilitate. adapting the air supply to the varying structural features of the building.

The velocity of the air discharging from the-slots to form the air curtains is relatively high; that is to say, the velocity is much greater than that of the air flowing through the opening 0 and which provides the major portion of air for drying purposes.

Modified means for providing air curtain In some instances, particularly in old installations, the structural arrangement of, the mill may be such ass-to preclude the locating of the air ducts below the mill floor. InFig. 2A there is shown an arrangement wherein the elongated. air duct 61M is located above the mill floor and adjacent the machine frame. It is proivded with a plurality of adjustable air discharge tubes 64M arranged to form an air curtain as before described. It will, of course, be understood that means are provided to supply ,air to the duct 61M under pressure as required t form the high velocity air curtain.

Modification in which one side of machine is fully closed 1 quick access is necessary inan emergency; When.the

chine which extends upwardlyofirthe millfioor through V theinillfloor opening"0..

Iheapparatus for providing the dir curtains .'This" apparatus will be best understood by refer'enceto .willbe observed in Figs 1,2, and 4,there ispro vided in the mill. 11001 M a plurality of slots which extend longitudinally b'elowthe side walls of the closure.

.PrferablyLthere. is provided a plurality of air trunk'sectailingFigaosfagEach section comprises a duct 61, a blower 62-; and ian 'electric'xmotor. '63. for operatingthe (blower:

Thelblower discharges intoth'e 'duct 61, theairdischarg- *ing 'upwardly throughawplurality of relativelyinarrow tubes' 64; each of which' is provided with'aydamper 65 to controlthe direction ofzflow ofjthe discharged air. i

open area is provided along one sideonlyand the air curtain there established and maintained,.t;he side wall on the other'side of the machine is extended to the mill. floor. Such an arrangement is shown in Fig. 7. i p

In this instance the one side wall is provided a plurality. of horizontally sliding doors in theupper part of the side wall and a plurality of horizontally jsliding doors 71 in' the lower part; By sliding the. door 1o 5: gitudinally of the side wall, accessrna'ybe, gained. to any part of that side of the machine. Since the oppositeside ofthe machine is providedwith an openlowerfara' traversed by an air'curtain as-before described, it is obvious thataccess can be had continuously to-that side of the machineas well as the ability to observe thee'ntire .lower part of that side of'the machine" during opera fionh. v M V I The modification shownin Figs. 8 and 9 I It will be appreciated that. thedrying rolls are highly heated. Hence some of the radiant heat from. the por= 65' der journals having a bearingin the frame to permit the tions inoperative alignment, one 'of which is shown in de- 0. can be. put iniplaice and'clampedby'means of-fthe the; end of cylinder. by means o f a plurality of circumferentially spaced leg port1ons'85; showmthe disc. 831 is. provided iwith'i a new,

air openings 86 and a'plurality of radial vanes 87'so' that, in the rotation of the cylinder, air is caused to circulate in the'space between the cylinder end and the confronting face of the disc.

The disc 83 is preferably made of a bright metal, such asstainless steel, and the face confronting the end of the cylinder 80 is preferably provided with a black coating 88 for heat-absorbing purposes.

Conveniently, the disc may be provided with a manhole member 89 positioned over the usual manhole cover usually found in the end of the drier rolls.

The control panel Referring to Fig. 1, there is provided preferably adjacent one end wall of the drying machine closure an electrical control board or panel 90. This control board contains a plurality of switches 92 wired and connected to control the various motors for operating the blowers which supply the major part of the air for drying purposes, the motors which operate the blower, which supply the high velocity of air to establish and maintain the air curtains, and the motors for operating the exhaust blowers. The electrical arrangement is such that any or all motors operating the blowers for supplying the major part of the air can be started or stopped at will; also,

any or all of the motors for operating the blowers providing the high velocity air for the air curtains can be started and stopped at will, and the like control is provided for the motors that operate the exhaust fans.

The operation of the various motors, the electrical controls therefor, and the positions of the dampers or other means governing the velocity and volume of air discharging into the closure, and the air and vapor exhausted from the closure is such that a substantial balanee is maintained within the closure and in the mill adjacent the side walls so that not more than a relatively small amount of air can pass through the air curtain. In practice,- it may be advisable to permit a relatively small amount of air to pass through or into the air curtains to assure against the discharge of moist air from the drier into the adjacent portions of the mill.

The air curtain air, as it passes upwardly, preferably strikes the solid inner side wall of the closure just above the lower marginal portion thereof and, because of its high velocity, will tend to follow along the inner side face for. some distance. This, to a certain extent, acts as an insulator and, in any event, prevents the curtain air from passing into the mill area outside the closure.

I claim:

1. Apparatus for use in combination with a paper-drying machine having at least a substantial portion extending upwardly of a mill floor, said apparatus comprising a roof extending over the top of the machine and being of greater width than at least that portion of the machine which extends upwardly of the mill floor so that the roof extends beyond each side of said last-mentioned portion ofthe. machine, end walls positioned at the ends of the the said roof and joining said end walls at each end, at least one of said side walls extending from adjacent the.

outertmarginal side portion of the roof and terminating in a plane substantially above the mill floor, 'therebyproviding anopen area'between the' lower margin of that side wall and, the. mill floor which issubstantially coextensive in length with that of the'said sidewall, means for supplying air at relatively high velocity, air outlet-a means positioned longitudinally of! the saidside walls substantially coextensive. in'length with the said open area, being adjacentthe mill .fl'oor and being arranged to"dis-- chargeair upwardlyin the form of an aircurtain means communicating saidlair-su'pplying means with said air. outletimeahs whereby the curtain'of'a-ir' moves' at relatively high velocity across said open area in a direction to pass inwardly of the outer face of the adjacent side wall, other means for supplying a major part of the drying air to the machine, means for exhausting from the upper interior portion of the roof and walls air supplied by said major air-supplying means and the air supplied to form said air curtain together with the water vapor resulting from the drying operation, all said means being formed and adapted to supply air in such volume and velocity as to maintain such a balance between the space within and the air forming outwardly of said open area below the side walls that the air passing out the exhaust means is comprised mainly of that supplied by said major air-supplying means and said curtain.

2. The arrangement set forth in claim 1 together with means for heating the major part of the drying air.

3. The arrangement set forth in claim 1 together with means for heating the air forming the air curtain.

. 4. Apparatus for use in combination with a paper-drying machine having at least a substantial portion extending upwardly of a mill floor, said apparatus comprising a roof extending over the top of the machine and being of greater width than at least that portion of the machine which extends upwardly of the mill floor so that the roof extends beyond each side of said part. of the machine, end walls positioned at the ends of the roof, one end wall having an opening to provide for the entry of the web to the other and an opening for the exit of the web passing from the machine, longitudinal side walls substantially coextensive in length with the said roof and joining said end walls at each end, said side walls extending from adjacent the outer marginal side portions of the roof to a plane substantially above the mill floor, thereby providing an open area between the lower margin of each of the side walls and the mill floor which is substantially coextensive in length with that of the side wall blower means, air slots positioned below and longitudinally of the said side walls substantially coextensive in length with the said open area, being adjacent the mill floor and being arranged to discharge air upwardly, means communicating said blower means with said air slots, means for actuating said blower means whereby air at relatively high velocity in the form of an air curtain, is blown across each said open area in a direction to pass inwardly of the outer face of the adjacent said side wall, other means for supplying a major part of the drying air to the machine, means for exhausting from the upper interior portion of the closure formed by the roof and walls the air supplied by said major air-supplying means and that supplied to form said air curtain together with the water vapor resultingfrom the drying operation, said air-supplying means being formed and adapted to supply air in such volume and velocity as to maintain such a balance between the space within the side walls and air curtains and that outwardly thereof as will prevent the flow of more than a relatively small volume of air from the mill into said closure through the areas covered by said air curtains. V a

5. The arrangement set forth in claim 4 together with means for heating at least the major part of the drying air.

6. Apparatus for use in combination with a paper-drying machine having at least a substantial portion extending above a mill floor, said portion being positioned over an opening in the mill floor communicating with an underlying area, said apparatus comprising a roof. extending over the'top of that portion of the paper-drying machine which extends above themill floor and being of'greater widththan said machine portion so as to extend beyond each side thereof, end'walls positioned at the ends of the roof, one end wall havingan opening to provide for the entry of the web to and the other an'opening for the exit ofthe'web passing from the machine, longitudinal side wallssubstantiallycoextensive in length with the said roof and joining said endiwalls at each end, said side .wallsextending from adjacent the outer marginalside' portions of the roof to a plane substantially above the mill floor, thereby providing an open area between the lower margins of the side walls and the mill floor, which is substantially coextensive in length with that of the side walls, blower means, air slots positioned below and longitudinally of the said side walls being adjacent the mill floor and being arranged to discharge air upwardly, means communicating said blower means with said air slots, means for actuating said blower means whereby at relatively high velocity in the form of an air curtain is blown across said open areas in a direction to pass inwardly of the outer side of said side walls, means for supplying the major portion of the drying air to the machine through said first mentioned floor opening, means for exhausting, from the interior portion beneath the roof, the air supplied to the machine through said mill floor opening and by said air forming the air cur-,

tains together with the water vapor resulting from the drying operation, said air-supplying means being formed and adapted to supply air in such volume and velocity as to maintain a balance between the space inwardly of the curtains and walls and that outwardly of said open area below the side walls as will prevent the flow of more than a relatively small volume of air from the mill in a direction to be discharged by said exhaust means.

7. The arrangement set forth in claim 6 together with means for heating at least the major part of the drying air.

8. The arrangement set forth in claim 6 in which the means for supplying the major part of the drying air comprises a chamber underlying the mill floor opening at the top into said mill floor opening and including blower means for discharging air into said chamber for passage through said floor opening.

9. Apparatus for use in combination with a paperdrying machine having at least a substantial portion extending upwardly of a mill floor, said apparatus comprising a roof extending over the top of the machine and being of greater width than that portion of the machine which extends upwardly of the mill floor so that the roof extends beyond each side of said portion of the machine, end walls positioned at the ends of the roof, one end wall having an opening to provide for the entry of the web to the machine and the other an opening for the exit of the web passing from the machine, longitudinal side walls substantially coextensive in length with the said roof and joining said end walls at each end, one of said side walls extending from adjacent the outer marginal side portions of the roof substantially to the mill floor and the other to a plane substantially above the mill floor, the latter thereby providing an open area between its lower margin and the mill floor which is substantially coextensive in length with that of the superposed side wall portion, blower means, air slots positioned beupper interior portion of the closure formed by said.

roof and walls the air supplied by said major air-supplying means and that supplied to form said air curtain together with the water vapor resulting from the drying operation, said air-supplying means being formed and adapted to supply air in such volume and velocity as to maintain such a balance between the space Within the closure and that outwardly of said open area below the said side wall as will prevent the flow of more than a relatively small volume of air from one side of the open zone between the lower margin of the side wall and the mill floor to the other.

10. The arrangement set forth in claim 9 in which the major portion of the drying machine is positioned over an opening in the mill floor communicating with an area below and the major portion of the air for drying is supplied through that opening.

11. The arrangement set forth in claim 9 in which means is provided for heating at least the major portion of the air supplied to the drying machine.

12. The arrangement set forth in claim 9 in which means is provided for heating at least the air supplied to form the air curtain.

13. The arrangement set forth in claim 9 in which the means for providing the air curtain comprises a number of operative sections and means for actuating all or any part thereof.

14. The arrangement set forth in claim 10 which includes an open top chamber underlying the mill floor opening with the open top thereof communicating the chamber space with the closure space formed by the top and side walls, and blower means forcing air into the said chamber to supply the major portion of the air for drying purposes.

15. The arrangement setforth in claim 10 which includes an open top chamber underlying the mill floor with the open top thereof communicating the chamber space with the said closure space, and blower means located in said chamber space and having structure discharging air upwardly through the mill floor to provide the said air curtain.

16. Apparatus for use in combination with a paperdrying machine comprising a plurality of heated drying rolls and having at least a substantial portion extending upwardly of a mill floor, said apparatus comprising a roof extending over the top of the machine and being of greater width than that portion of the machine which extends upwardly of the mill fioor so that the roof extends beyond each side of said portion of the machine, end walls positioned at the ends of the roof, one end wall having an opening to provide for the entry of the web to the machine and the other an opening for the exit of the web from the machine, longitudinal side walls sub stantially coextensive in length with the said roof portion and joining said end walls at each end at least one of said side walls extending from adjacent the outer marginal side portion of the roof and terminating in a plane substantially above the mill floor, thereby providing an open area between the lower margin of the said side wall and the mill floor which is substantially coextensive in length with that of the side wall portion blower means, means for blowing air at relatively high velocity across said open area in a direction to pass inwardly of the said side wall, thereby establishing an air curtain across that area, means associating the ends of those drying rolls located in the said open area for intercepting at least a part of the radiant heat from the rolls to prevent the same from passing through said air curtain into the mill.

17. The arrangement set forth in claim 16 in which the means for intercepting at least a part of the radiant heat from the rolls comprises a disc of bright metal, spaced from one end of the roll and having the one face confronting the end of the roll, the said face being substantially black.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,977 686 I April 4, 1961 Arthur G. Stout It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent. should read as corrected below.

Column 8, line 11, strike out "the air forming! and Insert the same after :"and" in line 14, same column.

Signed and sealed this 3rd day of October 1961,

I (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents USCOMM-DC

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