US1776586A - Method of saturating sheet material - Google Patents

Description

Sept. 23, 1930. G. P. HEPPES METHOD 0 F SATURATING- SHEET MATERIAL Filed Feb. 5, 1921 2 Sheets-Sheet l S p 9 Q VG. P. HEPPES ,58

METHOD OF {SATURATING SHEET MATERIAL Filed Feb. 3, 1927 2 Sheets-Sheet 2 r v 1 4 5 Q I Jywggexw.

4 I eagyej Patented Sept. 23 1930 UNIT-ED STATES PATENT OFFICE GEORGE P. HEPPES, OI CHICAGO HEIGHTS, ILLINOIS, ASSIGNOR, BY HESNE ASSIGN- MENTS, TO THE PATENT AND LICENSING CORPORATION, OF BOSTON, MASSACHU- SETTS, A CORPORATION OF MASSACHUSETTS METHOD OF SATURATING SHEET MATERIAL Application filed February a, 1927. Serial No. 165,558.

This invention relates to apparatus for saturating absorbent material particularly in sheet form and has for its objects not only to saturate the material to a higher degree than has been possible with apparatus heretofore in use for that purpose, but also to control the saturation so as to produce definite degrees of saturation less than complete if so desired. My invention finds a particular practical exemplification in the problem of saturating sheets of felted fibrous stock commonly used as a foundation or base for fabricated roofing. Such stock is commonly made of rag or asbestos fibers or mixtures of these or other fibers, the sheets being formed on a paper-making machine so that the fibrous material is interfelted into a bibulous structure capable of absorbing a considerable quantity of suitable saturants. In the manufacture of roofing elements from raw felt, it is customary to saturate the felt with a suitable waterproofing material so as to make the sheet water repellent. For this purpose, a low melting-point asphalt is customarily used since asphalt of this kind can readily be.

heated to a relatively high degree of fluidity without raising the temperature so high as to char or injure the fibrous material of the sheet when immersed in a bath of the molten saturant for a sufficient time to effect approximately the maximum degree of saturation possible from a single immersion of the sheet. It has been found that a sheet of raw roofing felt when immersed in a bath of asphalt having a melting point of from 120 to 150 F. heated to a temperature of approximately 300 F.is quickly saturated to about 70 per cent. of its theoretical capacity, after which no more saturant enters the sheet, no matter how long the sheet may be left in the bath. The saturation of roofing felt in the manufacture of roofing units according to general practice thus rarely reaches 80- per cent.

of the theoretical maximum. Feltwhich is saturated to that extent only is thus left with pores and voids capable of absorbing'some 20 per cent. of moisture. This constitutes an inherent weakness in the roofing elements made from the felt. which makes them subject to deterioration by absorption of moisture traction of the asphalt in the pores and voids 1 of the sheet together with whatever residual gases and vapors may be entrapped in such pores and voids, sucks some of the excess asphalt from the surfabe into the sheet so that a sheet thus saturated and cooled is found to have absorbed saturant to very nearly 100 per cent. of its theoretical capacity. I have found moreover that a saturation very close to the theoretical maximum can be obtained by cooling the sheet with an excess of saturant on one face only of the sheet. This is believed to be due to the fact that the face from which the excess is substantially entirely removed when the sheet leaves the bath starts to cool immediately, causing the asphalt in the pore spaces at the surface of the felt to become sluggish and thereby to prevent air from being sucked into the sheet through that face. On the other hand, the surface on which an excess of hot asphalt is allowed to remain does not begin to cool at once since it is kept heated for a time by the presence of the layer of excess asphalt on the face. The cooling therefore of the asphalt in the sheet proceeds from the uncoated face of the felt and as the saturant and gases within the sheet contract, they suck in more particularly the excess from the coated face, suction of air from the uncoated face being practically prevented by the initial chilling of asphalt in the superficial pore spaces thereof. In this manner, satisfactory results have been obtained in the saturation of roofing felt by excess. being left on one face only of the felt as it emerges from the saturating bath.

It has been customary heretofore to run the sheet of roofing felt which has passed through the saturating bath to a cooling device comprising a looping mechanism which receives the saturated 'felt in festoons and feeding the saturated sheet from the saturat-.

allows it'to cool by expdsure to the air. In

ing tank to the looper, it has heretofore been found necessary as a practical matter to remove excess saturant from the faces of the sheet. Unless this were done, difliculty has been experienced with traction of the feeding rolls, excess saturant on the sheet causing the sheet to slip on the rolls. A further ditficulty has arisen from the presence of excess saturant on'the' lower face of the sheet due to the fact that such excess was liable to cause the sheet while cooling to stick to the looper bars over which it was festooned so that upon attempted removal of the sheet, it was liable to tear. By my invention, I provide means for squeezing and feeding the sheet from the saturating bath to the looper mechanism but leaving a sufiicient amount of excess saturant thereon without, however, losing traction. Moreover, the apparatus embodying my invention prevents the sticking of the saturated sheet to the looper bars.

An. important feature of my invention is embodied in a special type of squeeze roll which engages the upper face of the sheet as it emerges from the saturating tank. This roll is provided with recesses of desired-number, size and shape formed on the face of the roll, these recesses serving as temporary reservoirs to receive some of the excess saturant on the face of-the sheetleaving the saturating tank and to. permit such saturantto pass the squeeze rolls and to remain on the face of the sheet. during the subsequent cooling thereof. The amount of excess saturant remaining. on the face of the sheet. after passing the rolls may be accurately controlled by the size and shape of the" holes and the spacing of the rolls. Various other advantageous features will bezapparent to one skilled in the art from the following description and on the drawings, of which,-

Figure 1 represents diagrammatically apparatus for carrying out some of the steps of manufacture of roofing, this apparatus Q containing an embodiment of my invention.

' Figure 2 illustrates another arrangement of apparatus containing an embodiment of my invention.

Figure 3 illustrates apparatus for use with a modified form of my invention.

Figure 4 indicates a fragment of sheet showing the pattern of .excess asphalt lefton a face thereof by a roll'such as shownin Figure 5. r Figures 5, 6 and 7 are fragmentary perspectivesof rolls having recessed portions of various configurations.

Figure 8 shows a, roll with recesses of adjustable capacity.

Figure-9 is a fragmentary transverse section of a roll such as is'shown in Figure 8.

Figure 10 is a perspective of a serrated doctor used with the apparatus indicated in Figure 3.

Figures 11, 12 and 13 are fragmentary perspectives of looper bars having projections of various shapes thereon.

Referring to Figure 1, a roll of raw roofing felt is indicated at 20. This felt may be led by suitable guide rolls into'a saturating tank 21 which is customarily provided with means for maintaining a pool of saturant therein at any; desired temperature. The sheet may be led over a series of rolls 22 in the tank to secure thorough contact with the saturant and to permit bubbles of air and vapor issuing from the sheet to escape therefrom. The sheet upon leaving the bath of molten asphalt in the container 21 may be led directly to a pair of squeeze rolls 23, 24, or if desired may have the excess saturant on its upper face doctored therefrom as at 25, after which a secondary application of waterproofing material may be applied as by'a suitable spout 26. The material supplied for the secondary coating may be similar to that in the container 21 or preferably may be an asphalt having a higher melting point such for example as is commonly used for coating the saturated sheet. Of the pair of squeeze rolls 23, 24, which draw the saturated sheet from the tank and feed it toward the looper mecha-. nism, the lower roll 23 is adapted to contact With the upper face of the sheet, the upper roll 24 being adapted to engage the lower face of the sheet, the sheet beingthreaded between these rolls in such a manner as to tially all ofthe excess saturant thereon, the

recesses permitting substantial quantities of excess saturant to remain on the portions of the surface not touched by'the lands. In the normal operation ofthe machine, a slight excess Will be left on the squeezed areas of the sheet, heavier excess being left on the remainlUU ing areas. These recesses may be of any desired number, area, depth or shape. As exemplified in the form of roll shown in Figure 5, the recesses comprise a series of longitudinal grooves intersected by a series of peripheral grooves, these grooves being, by way of example, about one-quarter of an inch apart and having'a width and depth of approximately one-eighthof an inch. The number, size and distribution of the grooves, however, will depend upon the characteristics of. the saturant and of thesheet as well as the degree. of saturation desired. By regulating the size, number and distribution of i are preferably smaller than those in the. roll; 23, and if desired, the'roll 24 may havea the grooves in the face of the roll, the amount of'excess saturant left thereon after the sheet has passed between the squeeze rolls may be accurately controlled, this control being not subject to tampering with by operators of the machine. If the excess saturant left on the sheet is low melting-point asphalt such as is used in the saturating bath, it is desirable that the amount of excess thereof left on the face of the sheet be carefully regulated, sincea deficiency would result in an insuflicient saturation of the sheet while an excess would result in an inferior roofing element subject to slippage of the waterproofing coat of high. melting-point asphalt which is subsequently applied thereto, since an excess of low melting-point asphalt interposes a layer too readily affected by solar heat. Such readily affected layer of low melting-point asphalt remaining on a completely cooled sheet prevents a coating layer of high melting-point asphalt from direct engagement with and anchorage to the fibers of the foundation sheet. The roll illustrated in Figure leavesexcess saturant on the sheet in a checkered pattern such as shown in Figure 4, these crisscross lines. of saturant quickly spreading to form a fairly uniform layer of asphalt which is sucked into the sheet during the cooling thereof. Other forms ofroll surfaces may be employed, however, as found desirable or convenient, a few of these being illustrated in Figures 6, 7 and 8. It is obvious, however, that-many other patterns may be'devised such for example as spiral grooves which may be arranged to lead from'the center line of the roll face toward the ends thereof, such a pattern having the additional function of tending to keep the sheet prop erly stretched laterally. In order to facilitate adjustment of the capacity of a roll to pass excess saturant, I may provide recesses of variable capacity, as shown in Figures 8 and 9, wherein the rec'esses are shown as cvlindrical in form, the bottoms being the heads of screws 27 which are threaded into suitable holes 28 in the roll. Any pattern of recesses, however, which provides a satisfactory distribution of excess asphalt on the face of the sheet coming in contact with the roll comes within the purview of my invention.

If desired, the upper roll 24 of the pair of squeeze rolls, which in the apparatus illustrated feed the sheet from the saturating tank, may also be provided with grooves in its face. This roll is adapted to contact the under face of the sheet and for reasons hereinbefore set forth, it is considered advantageous in order to avoid certain practical difficulties in handling the sheet to remove most. if not all, of the excess asphalt adhering to .the sheet 'as it leaves the saturating bath. For this reason, the grooves in the roll 24 plain ungrooved face.

from the face thereof. be heated in order to prolong the fluid condi- It is understood, however, in case the sheet should be fed to apparatus in which, substantial excess saturant on the under face of the sheet would' not be objectionable, it is possible to leave any desired quantity of excess saturant on the under face as well as on the upper face. The excess asphalton the sheet after passing the rolls 23, 24 will in general be sufliciently fluid to spread under the act-ion of gravity and surface tension to form a fairly uniform layer on the sheet, this spreading action being indicated in part in Figure 4. If desired, however, the spreading may be hastened by a spreader such as a steam pipe 29 or bar 30 extending across the sheet and in light contact therewith.- The spreader should preferably be heated to prolong the fluency of the excess asphalt, but this is 7 not necessary.

Another arrangement of squeeze rolls may be employed involving the use of a third roll (not shown) located beneath the roll 23..

With such a set of rolls, the upper and lower rolls being f'plain and the middle roll being recessed, the sheet would receive two squeezes so as to remove more of the saturant from the lower face of the sheet while leaving a measured amount of excess on the upper face,

In the looping mechanism as indicated in Figure 1, a pair of feed rolls 31, 32 may' be I used to feed the sheet coming from the rolls 23, 24 into the looping apparatus. The sheet,

after leaving the squeeze rolls 23, 24'will. according to my invention, have a predetermined or controlled excess of Waterproofing material on the upper face thereof .and if desired a lesser excess on the lower face thereof. Some of this excess will normally be upon the upper face ofthe sheet when it reaches the feed rolls 31, 32. In order to avoid squeezingthis unabsorbed excess from the face of the sheet, I preferably provide the face of the roll 31 with grooves or other recesses which may be similar 'to those in the roll 23 so that the sheet is carried through these feed rolls without loss of traction and also without removal of the excess coating The roll 31 may also tion of the excess saturant on the upper face of the sheet. If substantial excess be lefton the under face of the sheet, the roll 32 should be suitably recessed to prevent squeezingsuch excess therefrom. The looping mechanism itself comprises essentially an endless carrier 33 composed of a pair of. parallel chains supporting by their ends a series of looper bars 34. The chains of the carrier 33 pass over and are driven by suitable sprocket wheels as at 35, the progress of the bars 34 being continuous and relatively slow.

The feed wheels 31, 32 feed the flexible saturated sheet into festoons between successive looper bars 34. A suitable idle roll 36 is The progress of the looper bars 34 is so timed in relation to the speed of the feed rolls 31,

' 32 that when a sufficient length of .the sheet has been fed between a pair of succssive looper bars to form a full festoon, the looper bar. comes in contact with the lower portion of the roll 36, the latter being of sufficient weight to pinch the sheet between it and the looper bar and thus to prevent any more of the sheet being fed into the festoon ahead of 'such looper bar. This results in the beginning of the next festoon which immediately follows this looper bar and thus the looping process is repeated. In order to prevent the squeezing of excess asphalt from the face of the sheet which overlies the looper bars, Imay also supply the roll 36 with recesses or [grooves to receive temporarily such quantities of excess saturant as still remain on the upper surface of the sheet when the looper bar comes in contact'with the pinching 'roll Instead 'of-remo'ving substantially all excess saturant from the bottom of the sheet as it leaves the saturating bath, I may if desired provide the face of the feed'rolls 24 and 32 with grooves so as to permit the device generally indicated at 41' a protective coat of high melting-point asretention of a substantial excess of saturant on theunder face as well as upon the upper face of the sheet. In order to avoid the well known dificulty usually arising from excess saturant on the under face of the sheet, namely, the liability of the sheet to stick to thelooper bars, I may provide the looper .bars with raised contact points (Figures form of stars,-knobs, or other spaced surfacesof small area to support the sheet and to hold the greater part of'the area of the lower face of the sheet out of contact with the looper bar.

The'ex osureof the sheet to the atmos-, phere in t e looper is preferably of suflicient duration to cool the sheet to approximately the melting point of the saturant in the sheet and at thesame time to allow substantially complete absorption of the asphalt into the sheet, resulting from the sucking in of the excess asphalt left on one-or both surfaces of the sheet As hereinbefore set forth, it is preferable to regulate the amount of excess of low melting-point asphalt left i on the face or faces of'the' sheet by forming the recesses in the squeeze rolls'of the proper size so that by the time the sheet is withdrawn from the looper, all of the excess on the faces thereof will have been drawn into the body of the sheet and will have become congealed within thepores and voids thereof. Upon leaving the looper, the sheet may be fed as by suitable feed rolls 39, 40 to a coating by which 11, 12 and 13) which may be in the' the two tanks.

phalt is applied to the upper face of the sheet, this coatin being ,preferably surfaced with' commmuted material such as crushed slate or its equivalent, this slate or grit being applied as by apparatus conventionally shown at 42 and rolled into intimate contact with the coating as by press rolls 43. The excess of coatingumaterial which may run off the upper surface of the sheetmay be caught in a receptacle44 from which also may be picked up coating asphalt to be applied in a thin layer to the under side of the sheet as 'is customary in the roofing industry.

In case the secondary application of asphalt by the spout 26 -(Figure 1) in the process of saturating the sheet is of high melting-point asphalt rather than the low melting-point variety, able receptacle 45 to catch anyexcess falling from the sheet,jthis'excess being transferred byany suitable means to the receptacle 44 to supply additional asphalt for the under coat of the sheet.

. l In Figure 2 is illustrated a modified form of saturating apparatus with which'l may use my; improved 4 this apparatus comprises a saturating ,tank 21 adapted to hold a bath of molten low melting-point asphalt. The usual rolls 22 are provided to guide the sheet through the .bath. Upon leaving the containeri21,'the sheet is preferably fedbetween a set of squeezing rolls 46, 47, '48 which emove' excess asphalt fromb' th faces of the sheet and also tend to work some of into the inmost p'ortionsof the sheet. The sheet may then e run directly to a second tank 49 containing a secondary saturating bath, or'may first be cooled as b a looper conventionally indicated at 50, or *another suitable cooling means. After suitable 1mmersion in the secondary saturating bath, the sheet may be then passed between squeeze rolls 23, 24, which are preferably similar to those shown in Figure 1, either or both of which may be recessed as hereinbefore described. From these rolls the sheet is taken to a looping apparatus similar to that shown in Figure 1, afterwhich the sheet is further operated on as desired. The use of a separate tank 49 for saturating permits greater control in the nature of the saturants applied to the sheet. If desired, the tanks 21 and 49 may contain the same kind of substance, in which case a connecting pipe 51 may be used to facilitate circulation through I may, however, use a highermelting-point asphalt in the tank 49 than in the tank 21 so that a greater amount of excess may be left upon the face of the sheet than would be practicable in the case of the low melting-point asphalt commonly used as an initial saturant. If an excess of low melting-point asphalt, beyond what can be I may provide a suit- \squeeze roll. As shown the asphalt absorbed in the process of cooling the sheet, is left on the face of the sheet, this unabsorbed excess prevents a proper bonding of the subsequently applied coating of high meltmg-point asphalt with the fibers of the foundation sheet, so that the coating on the surface of the shingle, being ordinarily surfaced with a layer of slate, is liable to slip when warmed by If, however, the secondary saturating step is carried out with high melting-point asphalt, some of this asphalt will be sucked into the sheet and will thus firmly anchor any excesswhich may be left upon the surface after the sheet has been cooled, this excess having a. sufficiently high me'lting-point to prevent slippage of the surfacing layers in hot weather.

In Figure 3 is illustrated another means for carrying out my invention. According to this form, the sheet is passed between the usual squeeze rolls 23, 24 upon leaving the saturating tank, which remove substantially all the excess saturant from the face of thesheet. Additional waterproofing material which may or may not be similar to that in the tank sheet which comprises the steps of first satu-' 21 is applied at once to the upper face of the sheet as by a spout 26. The sheet then passes under a doctor having a notched or serrated edge as shown in Figure 10. A guide roll 53 may be placed Opposite to the doctor to support the sheet against the edge of the latter.

The quantity of asphalt left on the sheet to be absorbed may be controlled by the number and size of the notches in the doctor 52. It is obvious that such a doctor may be used on the under side of the sheet in conjunction with suitable means for applying excess asphalt to that side. I

Having thus described certain embodiments of my invention, it should be evident to those skilled in the art that various changes and modifications might be made therein without departing from its spirit or scope as defined by the appended claims.

, I claim 1. The method of saturating an absorbent sheet, which comprises applying an excess of molten saturant to the sheet, squeezing the sheet, applying excess molten saturant to the squeezed hot sheet, removing from the surface of the sheet all but a predetermined quantity of excess molten saturant substantially equal to the amount which the sheet can absorb .in cooling, cooling the hot saturated sheet to contract the saturant therein and cause said measured excess of molten saturant to be drawn into the sheet. r i

2. The method of 'sautrating an absorbent sheet, which comprises immersing the sheet in a bath of molten asphalt, removing substantially all excess asphalt from the surface of the sheet, applying to the hot sheet other 7 molten asphalt, removing from the surface of the sheet all excess molten asphalt, except the sun of-a: summer day.

saturant equal to the amount which the sheet can absorb in cooling, cooling the hot saturated sheet to contract the saturant therein and cause the said pre etermined quantity of molten saturant to be drawn into the sheet and subsequently applying coating, asphalt to said sheet. 1

3. The method of saturating an absorbent sheet, which comprises applving an excess of saturant to the sheet, removing substantially all excess hot saturant from the surface of the sheet, applying to the hot sheet other molten saturant having different characteris tics from the first saturant, removing from spaced zones of the surface of the sheet substantially all excess saturant but leaving on the surface of the sheet a predetermined quantity of excess molten saturant substantially equal to the amount which the. sheet can absorb in cooling, cooling the hot saturated sheet to contract the saturant therein and cause the said predetermined excess of molten saturant to be drawn into the sheet and subsequently.

applying coating asphalt to the sheet. I

a. The method of saturating an absorbent rating the sheet with molten asphalt, applying to the hot saturated sheet additional molten asphalt, removing from the surface of the sheet all excess molten asphalt except'a predetermined quantity sub- 5. The method of saturating an absorbent sheet which comprises the steps of first saturating the sheet with molten asphalt, applying an additional quantity of molten asphalt to the thus saturated sheet while the s eet is hot, said'additional amount being substantially equal to that which the sheet can absorb in cooling, and cooling the hot saturated sheet to contract the saturant therein and cause the said additional quantity of molten asphalt to be drawn into the sheet.

6. The method'of saturating an absorbent sheet which comprises the steps of saturating the sheet to substantially of its theoretical capacity and providing an excess of molten saturant on the sheet, removing from a surface of the sheet excess molten saturant except fora predetermined quantitysubstantially equal to theamount which the sheet can absorb in cooling and cooling the hot saturated sheet to contract the saturant therein and cause said measured excess molten saturant to be drawn into the sheet.

7. The method of saturating an absorbent sheet which comprises maintaining the sheet in a heated condition durin the steps, in a cont nuous operatlon, of mmerslng the sheetto saturate the same and cause the saturant to penetrate substantially the entire thickness of the absorbent sheet and providing an excess of molten saturant on the sheet, removing from the surface of the sheet excess molten saturant except for a redetermined quantity substantiall e ua to the amount which the sheet can absor in cooling and cooling the saturated sheet to contract the hot .saturant therein and cause the said excess of molten saturantto be drawn into the sheet.

8. The method of saturating an absorbent sheet which comprises maintaining the sheet in a heated condition during the ste s, in .a continuous operation, of immersing t e sheet to saturate the same and cause'the saturant to penetrate substantially the entire thickness thereof, and providing an excess of molten saturant face only of the sheet excess molten saturant execept for a redetermined quantity substantially equa to the amount which the sheet can absorb in cooling and cooling the saturated sheet to contract the hot saturant therein and cause the said measured excess of molten saturant to be drawn into the sheet. The method of saturating an absorbent sheet which comprises maintaining the sheet in a heated condition continuous o eration, of immersing the sheet to saturate't e same and cause the satu'rant to'penetrate substantially the entire thickness of the sheet and providing an excess of molten saturant on the sheet, rcmovingbfrom the surface of the sheet, without su stantially indenting the sheet, excess molten saturant except a predetermined quantity. substantially e ual to the amount which the sheet can a sorb in cooling, continuously passing the hot saturated sheet, "with the through a,coo1ing measured excess thereon, zone in an unrolled' condition whereby to subject both surfaces of the sheet to cooling atmosphere to contract the hot saturant within the sheet and cause the said measured excess of molten saturant to be drawn therein, continuousl advancing the thus substantially comp etely saturated sheet to a coating zone and applfying coating material to the surface thereo and in finally applying comminuted surfacing material to the sheet as it advances from the coating zone.

In testimony whereof I have aflixed my signature. I

.' p GEORGE HEPPES.

on the sheet, removing from one during the steps, in a

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