US1598980A - Method of and apparatus for drying moving material - Google Patents

Description

Sept. 7 1926.

T. B. MUNROE METHOD oF AND APPAmvrusF012A DRYING MOVING MATERIAL 4 Sheets-Sheet l Filed Sept. 12. 1925 Sept. 7 1926. 1,598,980

T. B. MUNROE METHOD 0F 'AND APPARATUS FOR D RYINGMOVING MATERIAL Filed Sept. l2. 1925 4 Sheets-Sheet L aucun.

Sept. 7 1926. 1,598,980

T. B. MUNROE METHOD oF AMD APPARATUS FOR DRYIMG MOVING MATERIAL Filed sept. 12 l 1925 l4 Smets-smeet 5 EM rf sept. 7, 1926. 1,598,980

T. B. MUNROE I METHOD oF AND APPARATUS FOR DRYTNG Movme MATERIAL Filed sept. 12 1925 4 sheets-sheet 4 Lgf f5 \Jo *4W v gin/manto@ .ZLMazzzzoe aucun/1j Patented Sept. 7, S1926.

UNITED. STATES PATENTCFFICE.;

TBEADWAY B. MUNRQE, or CHICAGO, ILLrNoIs, AssIGNon 'rol marianne a Coat-1 PANY, INC., oF CHICAeo, ILLINOIS, A ConPoaA'rIoN orJnILAvwuu:`

IIETHCD or AND APPARATUS I 'oa DRYING novINe HATEBIAI.. g

Application mea sepcembef 12, 1925. serial Nol 56,010.

' This invention relates to a method of and an apparatus for drying-sheets of artificial heat insulating lumber, known on the market as Celotex, and has for its object to improve the procedures heretoforeL proposed.

With this and other objects in view, the invention consists in the novel steps and combinations of steps constituting the process and in the novel parts and combinations of parts constituting the apparatus, all as will be more fully vhereinafter disclosed and particularly pointed out in the claims.

Referring to the accompanying drawings forming a part of this specification in which like numerals designate like parts in all the views.

Fig. 1 is a diagrammatic plan lview of two Vunits of the drier constituting the invention;

Fig. 2 is a longitudinal sectional view of a portion of the parts shown in Fig.4 l;

Fig. 3 is an enlarged sectional view of a portion of the parts shown in Fig. 2, and illustrating the construction of the drier on each side of a steam duct;

Fig. 4 'is a transverse sectional view taken on the line 4-'4 of Fig. 2, looking in the vdirection of the arrows;

Fig. 5 is` a sectional view taken on the line 5-5` of Fig. 4, looking in the direction of the arrows;

Fig. 6 is a sectional view taken on the line 6 6 of'Fig. 4, looking in the direction'- of the arrows' Fig. 7 is a sectional view taken on the line 7 7 of Fig. 1 looking in the direction of the arrows; and

Fig. 8 is a sectional view taken on the line 8-8 of Fig. 5 looking in the 4dir ection of the arrows.

In order that the invention may be the better understood, it is said: This invention is especially adapted for drying sheets of heat insulating artificlal lumber that are now made from bagasse bers'admixed with fibers derived from wood and known-to` the trade as Celotex sheets. The mixture of fibers are first passed over s. sheet forming machine (not shown). which forms them in widths of about sa 10. or 12 fe t. The sheets are then passe through the drier ofths finvention in Continuous lengths, and for a distance of, say about 800 the wet is about one half inch and after' being dried they are Cut up into boards of any desired dimensions. In practice, it is found thatif, the heat insulating artificial lumber.,` or- Celotex sheetsare made up from bagasse fibers alone, Ethesaid sheets are apt to dry unevenly, tos warp, and to require a relatively lon time in passing a desired product through the drier, thus reducing the output of the mill. If it is attempted, on the other hand, to speed up the commercial reduction of these sheets, as by increasing t e teIn-.

Pelatlll'e 0f the air employed in the drier,

it is found that before vany substantial practical `results can be attained, the air will have to be so hot as will unavoidably Scorch the outer surfaces of the drying sheets, so

that the latter will be injure ing will also be found tobe stilliuneven and to give rise to an objectionable warping ofthe inished sheets.

In Yaddition to this, Celotex sheets are and the dryj highly heat insulating in their properties 'I and are provided with greater or less quantities of water resisting or'water proofing materials usually in the form of an aluminum resinate or other well known water resisting compound, and'when air is employed as the drying fluid it is found heat insulating water resisting layers are readil formed on their outer surfaces in the driers while the' in-A terior portions of the sheet have relatively large percentages of theiroriginal -water .stil

present. In fact, these layers seem to retard the heat in Vreaching" the interior, and to. retard `the water there present in reaching the exterior of the sheets.

On the other hand, it is found thatif the original bagasse bers are` admixed with4 a 'percentage of other fibers derived from wood, such for exampleas the waste Wood fibers from a paper mill, orV if vdisinte ated or ground. up paper stock, .is admixe with the bagassefibers, the drying action itself becomes even and satisfactory. But Solon as air is used as the drying medium even i at a temperature above 250 F., or is .heated u'p to a temperature of-sayi300 F., 350 F.;

or higher, which itis very desirable to, do, if a high speed of Yis to. be attained,-

the surfacesof the Celotexj-sheets will"'still be 'provided the objectionableheat inand lz yers',:and or 1000 feet. The thickness of. these sheets still be to an obiectmnable extent,

s ulating although the dring action may be free from warping. ut again, it is found that if the above mixture of bagasse fibers and ,fibers derived from wood is provided in the ypenetrate throughouty the interiors thereof,

and tol eiiciently remove the water present by evaporating the same.` In order, however, to employ superheated steam efliciently, air should be substantially excluded from contact with the sheets, .for at the temperatures mentioned any free oxygen .present is liable to produce an objectionable scorching of the sheets and sometimes a fire in the chamber which is impossible when steam is used.

Accordingly,in carrying out this invention, one first provides a drier construction which is, substantially air and steam tight,

except at its ends. The drier itselfbeing ysome 800 or 1000 feet long, or longer, and

the Celtex sheets being about one half inch in thickness, it is found not necessary to seal the inlet and exit ends of the drier, although said ends may lie more or less sealed `by flaps of canvas against the escape of the steamif soydesired. In constructing an airtight drier fulfilling the above requirements, one ay proceed as follows:

Rerflerring more particularly to Fig. 4, any suitable concrete or gther foundation 1 maybe provided, and on this foundation is placed a suitable box-like structure 2 which may extend the entire length of the drier. The outside of the structure 2 may be provided with any suitable heat insulating material 3, such for example as the finished Celotex material abovevmentioned after it has been cut to the desired dimensions. Inside the structure 2 are provided the vertically disposed partitions 4 and 5, which are disposed say 2 or 3 feet from the vertically disposed walls 2 of the box-like structure, t) provide the spaces or passage Ways 43 and 44, while inside the ypartitions 4 and 5 are disposed the various operatingparts of the drier itself. That is to say, ya plurality of horizontally disposed rows of rollers 6, 7 and 8 are provided and on the ends of these lrollers are disposed sprocket wheels 9, 10 and 11,'by which the rows of rollers are continually turned s`o as to move lengthwise of the drier the Celotex sheets 12', 13 and 14. The movement` of these sheets is comparatively slow, or say about as fast as one would walk at a slow gait. The actual speed, however, depends of course upon thev temperature of the drying mediumand the 'eiicienc with which said medium performs its duties. Also disposed inside the drier between the partitions 4 and 5 are a plurality of headers 15, 16, 17

and 18, which feed a plurality of rows of heating coils 19, 20, 21 and 22 extending throughout the length of the drier. The headers lettered from 15 to 18 are fed by the heater pipes 23, 24, 25 and 26 connected to the pipe 28 fed by the main heater supply 80 pipe 29 as shown. It will be understood that each of the coils such as 19, 20, 21 and 22 are made up of a series of coils that are disposed longitudinally of the drier for considerable distances and that they are inter- 35 -rupted by the steam inlet or distributing members 33 as will presently appear. That is to say, the main heat supply pipe 29 feeds a heat carrying medium into the heating coils lettered Afrom 19 to 22, through a plu- 90 rality of connections such as 23, 24, 25 and 26 at various points, and the function of these coils is to maintain a very high temperature of say from 250o F. to 350 F. or

higher inside the drier, While steam preferably in a superheated condition is distributed from the members 33 inside the drier at intervals along its length. Said steam contacts with the traveling Celotex sheets` and dries the same as will now be disclosed.

raised to the requisite temperature in said heaters, is sucked by the fan 31 out of said heaters and forced by said fan throughk the passage 32 into the steam distributors 33. These steam distributors as will be best understood from Fig. 4, are provided with a plurality of branches or forks 34, 35, 36 and 37, which are separated from each other by the spaces 38 and which forks are disposed above and below the Celotex sheets as illustrated. Thatis, the fork 34 is disposed be- 115 low the Celotex sheet 12, the fork 35 is disposed above saidsheet 12, and below the Celotex sheet 13, while the fork 36 is disposed below the sheet 14 and above the sheet 13 and the fork 37 is disposed above thc 120 sheet 14. These steam distributing forks are closed at their outer ends, but open on their side edges as best illustrated in Fig. 6, so that the hot steam carried thereby passes out of the same and reaches the upper and lower traveling surfaces of their adjacent Celotex sheets. The steam thus freed in the drier chamber comes' into contact with said sheets, and vaporizes the water ltherein-quite rapidly. In other' words, if 13 said steam is-well above the boiling point of Water, it rapidly converts the water presentinto steam, and the heat required to evaporate this Water is readily supplied' from the hea-ting coils lettered from 19 to 22. Theresult is `the volume of steam in the drier continuously increases, and therefore some provision has to be made for the excess 'of steam to escape from the drier.

This provision is found in the vent or exit tubes 40 leading into the heat exchange 41 that are disposed, along the side of the drier -and thus may a portion of the heat in the escaping steam be conserved and utilized for other purposes. In the meantime, the partitions 4 and 5 are provided at intervals with the openings 60 through whiohthe expended steam may escape into the passages 43 and 4415vhile the fans 31 continue to suck 43 and 44 'that are provided between the outer: walls 2 and the partition wallsf4 and 5 of the ,drier construction, and said conduit 42 is also provided with the inlets 45 and 46 permitting the steam that is liberated in the drier to be sucked into said conduit 42 and passed back into the heaters 30, so that the drying iuid or steam is circulated around and `around through the drier chamber, and out ofthe same continuously except for that portion which is taken out of the drier proper through the vent tubes`40`. In order 4 to regulate 'the escape of steam from the drying chamber, a check valve or damper 4.8 is provided in the vent tube 40. At suitable l intervals along the length ofthe drier there are provided doors 50 by which one may enter the drier proper for repairs, and through these doors areprovided windows 51 through which the operator .may view the internal operation of the drier and make certain that everything is working properly.

The operation of this drier will be understood from the foregoing, but may be brieiiy summarized as follow-s: The JCelotex sheets are fed from the sheet forming machine in a wet condition 4onto the rollers lettered from 6 to 8, these rollers are turned by sprocket chains `(not shown) through the medium of the sprocket wheels lettered.

from 9 to 11, and thus .are the sheets propelled continuously from Ithe forming end of thedrier to the finishing end of the same some 1 000'feet away, where they are cut into suitable dimensions for use. In the meantime, steam lor other heating medium is'fed from any suitable source' (not shown) through the main steam supply 29, and the heating iiuid is also fed from this supply throughout the length of the drier to the headers lettered from 15 to 18, which feed numerous sets of heating coils extending lengthwise of the vdrier and which coils are lettered from 19 to 22. These heating coils are interrupted, however, by the steam feeding members 33 as will be-clear from Figs. 4 and 6 of the drawin s, while the Celotex sheets continue to trave between the said sets of steam coils and between the individual lingers of the steam distributing members 33. Said fingers are` lettered from 34 to 37, as will be clear from Figs. 4 and 6; The steam when used in the heaters is preferably carried at a relatively high tempera.- ture of say from 250 F. to 350 F. In the distributors 33, the steam is preferably carried from 250 F. to 350 F., but other temperatures may be used when desired. This steam readily vaporizes the water present in the Celotex sheets, so that the same are dried rapidly and evenly, and especially when they contain a mixture of bagasse and wood fibers. The amount of water carried into the driers by the Ce-lotex sheets ma amount to as much as 200 tons daily, so 1t is important that the extra steam which is Owing to the presence of a water resisting compound in the fibers, the. water derived from the forming machine is held more tenaciously by the sheetswhen air is used as the drying medium than when steamis used and therefore an air drying process does not seem to so satisfactorily reach'thejl interior of the sheets and dislodge the water retained therein as does a steam drying process. Further, by the substantial exclusion of air from the drier, except -at the extreme ends of a^very long drier, and by keeping the wholel interior of the drying cham-- ber filled with steam as above disclosed, it is .found that the water is readily evaporated from the sheets in 'an expeditious,- uniform and satisfactory manner not attainable by the use of air, so that the output ofl the mill is greatly` increased. The heating coils readily resupplyT any heat that may be extracted fromthe drying steam whenl the wateris 'thus evaporated on the interior of the sheets, and they also aid in maintaining lzehightemperature inside the drying chamr `Theuse of waste furnace gases inthe heating coils not only enables one to attain yhigher temperatures in said heating coils, but it furnishes an enormous quantity of heat that may becarrie'd out lof the system by the steam escaping through the vent tubes 40, and utilized f or other purposes.

It is obvious that those skilled in the art may vary the details of construction, the 'arrangement of parts and the mode of operation, Without departing from the spirit of this invention, and therefore itis not desired to be limited to the foregoing disclosure except as may be re uired by the claims.

What is claime is:

1. The process of drying moving material which consists in causing ,said material to travel at a controlled rate of speed through a chamber from which air is substantially excluded; admitting superheated steam into said chamber in opposed and codirectional contact with said moving material to evaporate any water present in said material; venting out of said chamber any excess of vapor that may accumulate therein; and continuously passing said steam into and out of said chamber.

2. The process of drying moving material which consists in causing said material to travel at a controlled rate of speed through a chamber from which air is substantially excluded; admitting superheated steam at a temperature above 250 F. into said chamber in opposed. and co'directional contact with said moving material to evaporate any Water present in said material; venting out of said chamber any excess of vapor that may accumulate therein; reheating said steam after it has evaporated said Water; and continuously passing said steam into and out of said Y chamber.

3. The process of drying moving material which consists in causing said material to travel at a controlled rate of speed through a chamber from which air is substantially excluded; maintaining the interior of said chamber at a temperature above 212 F.; admitting superheated steam into said chamber. in opposed and codirectional contact With said moving material to evaporate any water present in said material; venting out of said chamber any excess of vapor that may accumulate therein; and continuously passing said steam into and out of said chamber.

4. The process of drying moving material Which consists in causing said material tov travel at a controlled rate of speed through a chamber from which air is substantially excluded; maintaining the interior of said chamber at a temperature above 212 F.; admitting superheated steam into said cham1 ber in opposed and codirectional contact with said movingmaterial at a temperature suliicient to evaporate any water present in said material; venting out of said chamber any excess offvapor that may acciimulate therein; and continuously passing said steam into and out of said chamber'.V

5.` In a drier the combination of a drying chamber; a set of rollers in said chamber adapted to move wet sheets of material from end to end thereof; means to maintain the temperature inside said chamber above a predetermined point; and means to circulate a drying fluid into and out of said chamber in contact with said material.

6. In a drier` the combination of a drying chamber; a set of rollers in said chamber vadapted to move Wet sheets of material from end t0 end thereof; means comprising a plu rality of steam coils to maintain the tem erature inside said chamberI above a pre etermined point; and means comprising a flui'd ,distributing member and heater therefor to circulate a drying fluid into and out of said lchamber in contact with said material.

7. Ina drier the vcombina-tion of a drying chamber; a set of rollers-in said chamber .adapted to move Wet sheets of material from end to end thereof; means comprising a plurality of steam coils to maintain the temperature inside said chamber above a predetermined point; means comprising a fluid distributing member and heater therefor to circulate a drying fluid into and out of said chamber in contact with said material; and

means to vent from said chamber any excess of Va or that may be evolved therein.'

8. n a drier the combination of a drying chamber; a set of Irollers in said chamber adapted to move Wet sheets of material from end to end thereof; means comprising a steam supply, a plurality of steam headers connected to said supply, and Va plurality of steam coils connected to said headers adapted to maintain 'the temperature inside said chamber above apredetermined point; and means to circulate a drying Huid into and out of sai-d chamber in contact with said material.

9. The process of drying a brous sheet of material containing moisture and provided With a vWater resisting compound,

Which consists in heating a chamber above A 212 F., and uniformly subjecting said sheet while in said chamber to the drying action of steam above 212 F. to evaporate a portion of the moisture present. i

10. The process-of drying a brous sheet of material containing moisture and provided With a Water resisting compound, which consists in heating a chamber above 212 F.; uniformly subjecting said sheet While in said chamber to the drying action of steam above 212 F. to evaporate a /portion of the moisture present; re-heatingf` said steam; and circulating the lsame into and out `of said chamber.

11. The process of drying Wet fibrous sheets of material providedl with a Water resisting compound which consistsin moving formly subjectingl said s eets t rough a drying chamber; heating said chamber fto a degree above 240 F.; uniformly subjecting the surfaces of Ithe moving sheets to the action-of superheated steam to evaporate a portion of the moisture on the interior of said sheets; and yre-l heating and circulating said steam into andof said chamber. O

i 13. The process of drying-moist fibrous sheets of material containingbagasse fibres that have been treated Witha-.water resistling comp'oudMWhich consists in. moving said sheets contir'u'ously through a drying chamber; maintaining the temperature of said chamber above a predetermined point; unithe moving sheets to the action of steam aving a temperature suficient to evaporate a portion of any moisture present on the interior of said sheets; and circulating said steam into and out of said chainber while re-heating the same.

14. The process of drying moist ibrous sheets of material containin a mixture of baga-sse and other fibres that ave been treated with a waterresisting compound which `consists in moving said (sheets continouslythrough a drying chamber maintaining the temperature of said chamber above a predetermined point; uniformly subjecting the moving sheets to the action of steam having a temperature sufficient to evaporate a portion o any moisture present on the interior of said sheets; removing any surplus vapor that may be evolved from said sheets; and

circulating said steam into and out of -said chamber while re-heating the same.

15. The process of drying'wet Sheets con taining bagasse fibres admixed with other fibres derived from Wood and with a water resisting compound which consists inmoving said sheets through a drying chamber maintained at a temperature above a predetermined point; substantially excluding the air from said chamber; and uniformly subjecting the moving sheet surfaces to the action of steam at a temperature suiicient to extract substantial proportion of the moisture .from the interior of said sheets.

16. The'process of drying wet sheets containing bagasse fibres' admixed with other flbresderived from wood and .Witha Water resistin `componnd which consists in moving sai sheets through a drying chamber maintained at a-temperature above a re.- d'etermined point; substantially exclu 'ng the air from said chamber; uniformly subjecting the movingsheet surfacesto the action of steam at a temperature sufficient o extract a substantial proportion of the moisturefrom the interior of said sheets; Withdrawinga'nd re-heating the steam thus employed; and returning the re-heated steam to said chamber.

17. The process of drying wet sheets containing bagasse bres admixed with other` fibres 'derived from wood and with a water resistin compoundwhich consists in moving sai sheets through a drying chamber maintained at a temperature above a redetermined point; substantially vexclu ing the air from sai-d chamber; uniformly subjecting the moving sheet surfaces to the action of steam at a temperature suicient to extract a substantial proportion of the moisture from the interior of said sheets; with- ."drawing and re-'heating the steam thus employed; returning the re-heated steam to said chamber; 'and removin from said chamber any surplus vapor derlved -from the moisture in saidsheets. v

In testimony whereof I aix my signature.

TREADWAY B. MUNROE.

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