US3758375A - Uid bath in web forming system method and apparatus for inserting vitreous fibrous material into liq - Google Patents

Abstract

VITREOUS FIBERS ARE DISPERSED IN A PREDETERMINED RATIO IN A LIQUID BATH. FROM THE LIQUID BATH QUANTITIES OF THE LIQUID AND OF THE FIBERS ARE CONTINUOUSLY WITHDRAWN FOR SUPPLY TO A USER DEVICE, AND THE LIQUID AND THE FIBERS MUST BE REPLENISHED TO MAINTAIN THE PREDETERMINED RATIO BETWEEN THEM. AN ENCLOSED SPACE IS LOCATED ABOVE AND OPEN TO THE UPPER LEVEL OF THE BATH AND INTO THIS SPACE THERE IS CONTINUOUSLY BLOWN AT LEAST ONE STREAM OF CARRIER GAS CARRYING REPLACEMENT FIBERS TO REPLENISH THOSE WITHDRAWN FROM THE BATH. IN ORDER TO PREVENT THE NEWLY INCOMING FIBERS FROM FORMING KNOTS ABOVE OR AT OR BELOW THE SURFACE OF THE BATH, A STREAM OF LIQUID IS CONTINUOUSLY DIRECTED INTO THE ENCLOSED SPACE TOWARDS THE UPPER LEVEL OF THE BATH IN SUCH A MANNER THAT IT INTERSECTS THE STREAM OF CARRIER GAS. THE STREAM OF LIQUID HAS A CROSS-SECTIONAL AREA SMALLER THAN THE SURFACE AREA OF THE BATH WHICH IS EXPOSED TO THE ENCLOSED SPACE AND A VELOCITY WHICH IS GREATER THAN THE STREAM OF CARRIER GAS AND WHICH IS SO SELECTED THAT THE STREAM OF LIQUID STRAIGHTENS AND ACCELERATES THE FIBERS IN THE STEAM OF CARRIER GAS SUFFICIENTLY TO INSERT THEM INTO THE BATH AND TO DEPRESS THEM BELOW THE UPPER LEVEL THEREOF.

Description

H. KEIB ET AL Sept. 11, 1913 METHOD AND APPARATUS FOR INSERTING VITREOUS FIBROUS MATERIAL INTO LIQUID BATH IN WEB FORMING SYSTEM 2 Sheets-Sheet 1 Filed Oct. 6, 1970 3&5 8303 026305 Emu INVENTOR Hunt Mu, 0

Sept. 11, 1973 H. KEIB ETAL 3,158,315

METHOD AND APPARATUS FOR INSER'IING VITREOUS FIBRUUS MATERIAL INTO LIQUID BATH IN WEB FORMING SYSTEM Filed Oct. 6, 1970 2 Sheets-Sheet FIBER mowcm Lla um SUPPLY MAN5\\ LIQUID SU PLY IN VEN TOR Hem; ken} BY km, V00

Mark

United States Patent Oifice 3,758,375 Patented Sept. 11, 1973 3,758,375 METHOD AND APPARATUS FOR INSERTING VITREOUS FIBROUS MATERIAL INTO LIQUID BATH IN WEB FORMING SYSTEM Heinz Keib, Wertheim (Main), and Karl Veeh, Hasloch, Unterfranken, Germany, assignors to Glaswerk Schuller GmbH, Wertheim, Germany Filed Oct. 6, 1970, Ser. No. 78,349 Claims priority, application Germany, Oct. 8, 1969, P 19 50 612.8 Int. Cl. D21f 1/02, 11/02; D2lh 5/18 US. Cl. 162-156 9 Claims ABSTRACT OF THE DISCLOSURE Vitreous fibers are dispersed in a predetermined ratio in a liquid bath. From the liquid bath quantities of the liquid and of the fibers are continuously withdrawn for supply to a user device, and the liquid and the fibers must be replenished to maintain the predetermined ratio between them. An enclosed space is located above and open to the upper level of the bath and into this space there is continuously blown at least one stream of carrier gas carrying replacement fibers to replenish those withdrawn from the bath. In order to prevent the newly incoming fibers from forming knots above or at or below the surface of the bath, a stream of liquid is continuously directed into the enclosed space towards the upper level of the bath in such a manner that it intersects the stream of carrier gas. The stream of liquid has a cross-sectional area smaller than the surface area of the bath which is exposed to the enclosed space and a velocity which is greater than the stream of carrier gas and which is so selected that the stream of liquid straightens and accelerates the fibers in the stream of carrier gas sufliciently to insert them into the bath and to depress them below the upper level thereof.

BACKGROUND OF THE INVENTION The present invention relates, generally speaking, to the processing of fibers of vitreous material, particularly of glass. More specifically, but still broadly speaking, the invention is concerned with the manufacturing of fibrous non-woven webs, usually called fleece, from glass fibers which are dispersed in liquid and which are applied together with the liquid onto a permeable movable support where the fibers are retained as a web, mat or fleece whereas the liquid can run off.

Still more specifically, the present invention is concerned with one aspect of the manufacture of such fleeces t and concerns a method and an apparatus.

In the manufacture of fibrous fleece in the above-identified manner-and there are other manners with which the present invention is not concerned-the fibers are dispersed in a bath of liquid, usually water, from which the dispersion is continuously withdrawn and which bath must be continuously replenished with additional water and additional fibers. The withdrawn dispersion is supplied to a user device well known to those skilled in the art where the carrier liquid, that is the water, is withdrawn or allowed to run off, as by passing the dispersion onto a sieve-like support which usually moves, so that only the fibers are retained by the support where they become interfelted and form the aforementioned fibrous fleece. The water is usually recirculated to the bath or to the flow of dispersion intermediate the bath and the user device. The fibrous fleece is dried, but usually a binder material is added to it before the drying in order to obtain or improve better cohesion of the fibers in the sliver.

It is known in the art that with this method of producing fibrous fleece it is possible only to utilize very short individual fibers; in the industry it is considered unusual if the length of such fibers even reaches 10 mm. It is not unknown entirely to utilize fibers having a length of approximately 20 mm., but this requires special steps which are expensive and which bring with them certain difliculties. Thus, for instance, in producing fibrous webs from shorter fibers it is customary to admix the fibers and the water of the bath in a mixing or heating device to assure better dispersion of the fibers in the water. This, however, results in breaking-up of the fibers and, if anything, tends to make them even shorter. The approaches attempting to use fibers whose length is in excess of 10 mm. require that the beater device be entirely omitted and this is undesirable in the context of what is known from the prior art because longer fibers tend to become interfelted more than shorter fibers and arrive in this condition in the liquid of the bath; therefore, if the beater device is necessary at all it is certainly more necessary with longer fibers in order to break up the interfelting of the same in the bath, than with the shorter fibers which tend less to interfelting and where the breaking-up of knots of such fibers is less necessary for this reason.

Of course, fibrous webs made from shorter fibers have many uses. On the other hand, however, there are a great many additional uses where the manufacture of the fibrous web or fleece from longer fibersthat is fibers in excess of 10 mm. length-is highly desirable. Fleece made with fibers of longer length has certain characteristics which are more advantageous than those of fleece made from fibers of shorter length, particularly because it is less susceptible to damage due to kinking or bending which in the fleece made of shorter fibers frequently results in breakage along the bending or kinking lines. Of course, the fleece made from longer fibers accordingly has a greater strength also.

Taking into account these desirable characteristics, and considering the difliculties which were encountered in making fibrous fleece with longer fibers, industry sought to circumvent the problem by improving the characteristics of fleece made with shorter fibers through the addition of greater quantities of binder material to thereby increase the strength of the webs. This approach was only marginally successful because, although it improved the coherence of the fleece, it also stiffened the fleece with a concomitant increase in the danger of breakage at bending or kinking lines, and substantially reduced the porosity of the fleece as compared to the fleece prepared with a lower admixture of binder material or fleece prepared according to other manufacturing methods. These two disadvantageous consequences are unacceptable, however, because such fleece is primarily used as carrier and/or reinforcement for bituminous roof coverings or coatings, as well as for articles made from synthetic plastic materials, and therefore must be resistant not only to damage due to bending or kinking, but also must have a high saturation capability which is determined by its porosity. Only in this manner it is assured that for instance in roof coverings, or in strip materials reinforced with such fleece and produced for convoluting about pipes as insulation, for tunnel sealing purposes, or for reinforcement of synthetic plastic articles, the bituminous material or the synthetic resin will quickly and completely soak into and saturate the fleece.

It thus became clear that it was still necessary to find a satisfactory approach for making fibrous fleece from vitreous fibers having a substantially greater length than heretofore possible, for instance up to or in excess of mm. On the other hand, however, the old difliculties still remained, namely the fact that when fibers of such length are used, the greater their length the more will be their tendency to form clumps, tufts and the like which are not acceptable in the finished product. It was determined that the primary factor in the formation of such clumps, tufts knots and the like was the increasing length of the fibers themselves; on the other hand, it was also found that the finer or thinner the fibers, the greater this tendency to the formation of knots so that this is a contributory factor. With respect to this latter aspect it must be noted that the manufacture of fibrous fleece from vitreous fibers of lesser thickness is preferred as opposed to the manufacture from fibers of greater thickness, because fleece made from fibers of lesser thickness has better properties, such as an improved ability to be rolled up and the like. In addition, the surface characeristics of the individual fibers were also identified as a contributory factor in the formation of knots. Fibers having for instance an etched or a corrugated surface tend more readily to form knots than fibers having a smooth straight surface.

It was recognized, of course, that it would be possible to eliminate the formation of knots in the fibers by suitable means, for instance by employing mixing or beating devices, but although this eliminates the formation of knots it in effect reduces the finished fibrous fleece to the same characteristics as if it had been made from shorter fibers to begin with, because the mixing and beating devices break up and accordingly shorten the longer fibers, so that the fibers might just as well have been supplied in shorter state to begin with. The resulting web or fleece does not have the improved desired characteristics. Without the use of such devices, however, the longer fibers will form the above-discussed knots and such knots will be present in the finished fleece, which is also not acceptable.

Again, an attempt was made to produce a fleece having the desired improved characteristics, by using shorter fibers to begin with. This involved the inclusion in the fleece of endless threads of organic material, or the inclusion of fabrics or the like. It was for instance proposed to supply to the incoming stream of liquid-fiber dispersion endless non-twined strands of filaments with the thought that in the rapidly flowing incoming stream of liquid/fiber dispersion the strands would separate into their individual filaments which in turn would become deposited in the shorter fibers settling on the screen or sieve of the fleece-producing apparatus due to maintenance of a certain speed differential with reference to the screen. It was assumed and intended that the deposition of the individual filaments would take place in form of loops or the like. Such endless strands have a higher mass than the incoming fibers because they consist of a plurality of parallel filaments and because of their initial cohesion as a strand they tend less towards the formation of knots. Also, it is theorized that the absence of ends on these endless strands and on the filaments making up such strandsas opposed to the presence of ends on the relatively short vitreous fibers-assists in avoiding the formation of knots.

It was found, however, that the improvement obtainable by the use of such filaments in terms of increased strength of the fleece is limited, because the position of the individual filaments within the fleece, and precedent thereto the separation and relative movement of the filaments originally supplied in form of a strand-can be controlled only with great difliculties, if at all. In order to obtain a really significant increase in the strength of the fleece it was therefore found that a relatively great percentage of such endless filaments would have to be added to the fleece, which is a decided disadvantage. Furthermore, this approach to all intents and purposes is possible only by using filaments of organic material; it is almost completely impossible to utilize inorganic material, such as endless filaments made of glass or generally vitreous material, because during the manufacture of endless vitreous filaments the individual filaments are coated with a sizing substance which either completely prevents or makes very diflicult the later separation of the individual filaments out of the strand which is supplied to the non-woven fabric, such as a fleece.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome the aforementioned difficulties.

More particularly, it is an object of the present invention to provide an improved method which avoids these problems.

An additional object of the invention is to provide an apparatus or arrangement for carrying out the method.

The present invention is based on the realization that from the point of view of avoiding the difliculties of the prior art it is critical how the vitreous fibers having a length up to or beyond 20 mm. are inserted into the liquid in order to form therein a homogeneous dispersion. This is true particularly in the manufacture of thin glass fiber fleece wherein generally the fibers are supplied directly from a fiber-producing instrumentality or else are supplied as nonfelted fibers and preferably should not pass through a beating or mixing device which would break them up and decrease their length. The problem is that the fibers may actually become interfelted and form clumps or knots even before they enter the liquid of the bath. Aside from this a further difliculty arises from the fact that due to the very small mass of the individual fibers their energy on impacting on the surface of the bath is insufficient to cause the fibers to pass through the surface and enter into the actual body of liquid. The longer and/or thinner the individual fiber is, the more pronounced is the danger that it will become deposited on the surface of the bath in convoluted form and will interfelt with other fibers to form knots, tufts, or the like. This tendency to the formation of knots or tufts may be further increased depending on the surface characteristics of the fibers. Of course, the problem was previously held within acceptable limits by using mixing or stirring devices to break up the thus-formed knots. Alternately, the approach taken in the art was to use very short fibers and to have a small ratio of fibers to liquid in the bath or dispersion.

As pointed out before, however, for the specified reasons it is not desirable to use stirring or mixing devices which would tend to break or shorten the longer fibers. On the other hand, it is not desirable to use a low fiberto-liquid ratio in the dispersion because an economic manufacture of high-quality fleece according to the socalled wet-fleece manufacturing process is possible only if high production speeds are achieved. This, in turn, is possible only if either very large quantities of dispersion having a low fiber-to-liquid ratio are turned over per unit of time, or else if the fiber to liquid ratio is substantially larger. In the event that the fiber-to-liquid ratio is low, and taking into account the necessity to achieve high production speeds, excessively large quantities of liquid must be turned over, that is must be conveyed between the dispersion bath and the fleece-producing user device; for many reasons, including the increased energy requirements for equipment causing such turnover of the dispersion, it is necessary to avoid the increased turnover and to achieve higher production by increasing the fiberto-liquid ratio as much as possible. The problem which therefore presented itself and was to be solved with the present invention was to obtain as uniform as possible a distribution of as long as possible vitreous fibers in a liquid bath, and further to obtain as high as possible a ratio of fibers to liquid while avoiding the formation of clumps, tufts, or the like, of fibers in the dispersion. Generally speaking, the invention solves the problem by supplying the fibers to the bath and engaging them before entry into the bath with a medium similar to that of the bath which individually contacts them, straightens them, and imparts to them energy which is sufiicient to cause them to penetrate through the surface of the bath and to enter into the actual body of liquid in the bath. According to the invention fibers of finite length are preferably used, but it is pointed out that instead of a length up to or somewhat in excess of 20 mm. such fibers may actually have a length up to several meters.

According to US. Pat. No. 2,787,542 it is known to make glass paper by supplying fibers of a length of at most 1 mm. in a carrier stream of gas, and to spray the fibers with water to therefore make them heavier and cause them to descend into a receptacle containing a bath. However, this prior-art approach requires the fibers to be extremely thin and to have a length of at most 1 mm, that is fibers whose characteristics are such that the interfelting and knot-forming problems with' which the present invention deals cannot under any circumstances occur. Fibers of such extreme thinness and shortness are blown by a gas blast into an upright shaft from laterally thereof, and are therein sprayed with water because otherwise they would descend much too slowlydue to their extremely small massin the shaft. Accordingly, a particular orientation and direction of the liquid spray for purposes of straightening longer fibers-which do not exist according to this prior-art approachis not taught and the concept of imparting increased velocity to the fibers by engaging them with such spray to therefore cause them to penetrate through the surface of a bath to which they descend, is absent.

In pursuance of the above objects and observations, and taking into account the existing prior art, the present invention, briefiy stated, relates in one aspect to a method of processing fibers of vitreous material, particularly of glass, which involves the steps of maintaining a liquid bath containing in dispersion a predetermined ratio of vitreous fibers, and continuously withdrawing a predetermined quantity of liquid and fibers from the bath for supply to a user device. The invention further provides for continuously blowing into a space located above and open to the upper level of the bath at least one stream of carrier gas carrying vitreous fibers for replenishing those drawn from the bath, at an angle smaller than 90 with reference to a vertical on the upper level of the bath. Furthermore, the invention provides for continuously directing into said space and towards the upper level of the bath also at an angle which is'smaller than 90 relative to said vertical at least one stream of liquid which intersects the stream of carrier gas and has a cross-sectional area smaller than the surface area of the bath which is exposed to the space. The stream of liquid has a velocity which is greater than the stream of carrier gas and which is so selected as to straighten and to accelerate the fibers in the stream of carrier gas sufficiently to insert them into the bath and to depress them below the upper level thereof.

The stream of liquid thus displaces the proportion of carrier gas in the incoming stream of fibers and causes the latter to impact upon the surface of the bath with sufiicient force to penetrate through the surface and to enter into the actual body of the bath.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of preferred embodiments when read in connection with the accompanying drawing.

6 BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic vertical section through an arrangement according to the persent invention;

FIG. 2 is a similar section through the main part of another embodiment; and

FIG. 3 is a top view looking in direction of the arrows of line IIIIII of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail it is pointed out that reference numeral 1 identifies a fiber supply conduit or channel of any desired cross-sectional configuration, for instance of circular cross-section. Through this fiber supply channel 1 is supplied or blown a stream 2 of carrier gas--usually aircarrying along vitreous fibers in the direction towards a receptacle 3 which accommodates a bath 4 composed of a dispersion of the fibers in a liquid. The upper lever of the bath is identified with reference number 5 and the drawing clearly shows that the receptacle 3 forms above the level 5 an enclosed space which is open to the level 5, and that the conduit 1 communicates with this space above the level 5. The cross-sectional configuration of the shaft-like or chimney-like portion of the receptacle 3 forming this enclosed space may be of any desired shape, for instance, rectangular, quadratic, circular or generally polygonal. Also, it will be appreciated that the space-forming portion need not be of on piece with the remainder of the receptacle accommodating the bath 4, but could be separate and suitably secured or connected with the remainder of the receptacle.

A conduit or channel 6 connects the receptacle 3 with the breast box 7 which in turn communicates with and supplies dispersion to the diagrammatically illustrated user device, that is the device which separates the liquid from the fibers and forms the fibrous fleece. In the embodiment shown, the user device consists of an endless perforated conveyor 13 and suction boxes 14. Such user devices are conventional and details of suitable devices of this type may be ascertained readily, for instance by reference to US. Pats. 2,488,700, 2,647,297 or 3,220,919.

The conduit 1 constitutes supply means, in a broad sense, for the stream 2 of gaseous carrier fluid and incoming vitreous fibers. It receives the fluid and the fibers from the diagrammatically illustrated supply, and it is emphasized that any suitable means for producing and propelling the stream of gaseous carrier fluid, and for inserting into it the fibers to be carried by it, can be utilized. The particular manner and devices for such purpose do not form a part of the present invention and are entirely conventional and well known to any person skilled in this art. Again, different types of devices, operating on variou principles, may find use. US. Pat. 2,518,744 contains a disclosure exemplary of a device which produces staple fibers by ejecting glass fibers from nozzles and directing tangentially directed gas streams against them on ejection, to thereby convert the ejected fibers to staple fibers. US. Pat. 2,904,453 teaches a device exemplary of the type in which glass fibers or a stream of molten glass are passed over a knife edge and at this point have a hot gas blast directed at them normal to their direction of advancement, whereby they become converted to staple fibers. The type of device exemplified by US. Pat. 2,897,874 is especially suitable for high-speed and high-quantity production; it delivers fibers centrifugally into a gaseous blast travelling transversely to their direction of advancement, whereby the fibers are deflected and further drawn out (attenuated) to form staple fibers.

Other devices which are also suitable are disclosed for example in US. Pats. 3,187,387 and 1,417,961. The former teaches a device which produces staple fibers by drawing continuous glass fibers on a rotating drum and subsequently severing them into shorter lengths. The latter patent teaches a device in which fiber-forming material is cut into slivers and are then forced through perforations of a cage. At the downstream side of the perforations the material is chopped in transverse as well as in longitudinal direction and subjected to air-blast loosening.

This review of the art is given here to indicate the versatility of the present invention and to make it clear that for its proper operation, and in order to arrive at the desired advantages, it is immaterial how the fibers are produced.

Of course, to obtain the advantages of high production speed it is advantageous to supply large quantities of fibers in the incoming air stream so that the choice of means for producing the air stream and the fibers carried by it should advantageously be such as to reflect the same. This is true, of course, also of the means of producing the fibers to begin with, for instance the above-described manner of drawing them on a fiber-drawing drum and subsequently severing them by chopping or the like.

As FIG. 1 also shows, the arrangement further comprises a supply conduit 8 communicating with diagrammatically illustrated liquid supply means and so oriented with reference to the channel 1 as to discharge a stream of liquid which intersects the stream of carrier gas carrying the incoming fibers. The stream of liquid is discharged at high pressure and accordingly high velocity, both in excess of the corresponding factors in the stream 2, and again any means suitable of propelling the stream of liquid through and from the conduit 8 in this manner may be utilized.

According to the present invention it is essential that the stream of liquid 9, preferably water, intersect the stream 2 before the fibers of the latter can have contact with the surface of the bath 4, and that it be at such velocity as to displace the carrier gas, break the fibers out of the stream 2 and carry them along downwardly towards the level 5 as illustrated in FIG. 1 whilestraightening the fibers in so doing, and impart to the fibers such additional velocity and energy that they not only impinge upon the level or surface 5 of the bath but are actually pushed through this surface and into the body of the bath 4 below the surface 5. In so doing the present invention prevents the fibers from interfelting and forming knots either above or on the surface 5 as is known in the prior approaches. Thus, whereas heretofore the incoming fibers were unable to penetrate the surface of the bath because of the prevailing high surface tension, they now are able to effect such penetration and the development of knots or the like at the surface 5 is avoided.

Moreover, once the fibers have been made to penetrate the surface 5 and have entered actually into the body of the bath 4, they do no longer tend to form knots within the body 4 itself. This is due to the substantial density reduction and is particularly true if the bath 4 in the receptacle 3 is agitated.

It is pointed out that such agitation should not only take place throughout the bath 4, but particularly also at and in the region of the upper level 5. To some extent this already results from the fact that the liquid of the stream 9 impinges upon the surface 5. It is further enhanced by the incoming water flow 11 which will be subsequently explained in more detail. However, additional means may be provided if and when necessary, for instance known stirring apparatus and/or pumps which turn over the dispersion to facilitate admixture of the fibers in the liquid of the bath 4, and which in conjunction with other factors acting upon and agitating the surface 5, should impart to the surface 5 a movement whose speed is at least equal to or greater than that of the incoming fibers.

Reference has been made above to the Water flow 11. The reason for this is that individual fibers may tend to adhere to the far wallthat is the right-hand wall in FIG. 1of the receptacle 3; also it is possible that in the upper outermost portion of the essentially conical stream 9 fibers might be displaced against and upwardly over the wall or walls of the receptacle 3. To remove these, one embodiment of the invention provides for flooding the wall with a continuous fiow 11 of liquid, usually water, which simply runs over the wall and flushes off any fibers adhering thereto. A very simple manner of achieving this is to provide a container 10 located at a requisite elevated level over an edge of which water continuously overflows onto the wall of the receptacle 3 which is to be cleared of adhering fibers. Of course, additional water must be continuously supplied to the receptacle 10 to continue such overflow but this will be self-evident to those skilled in the art.

It is, in fact, possible to utilize the water flow 11 for setting and maintaining the desired fiber to liquid ratio in the bath 4, simply by regulating the quantity of water in the how 11. Under most circumstances it will be sufficient to let the water flow 11 simply run over the associated wall so that it can enter the bath 4 without hav ing additional pressure imparted to it. According to an additional concept of the invention a conduit 12 may also be provided communicating in suitable manner with the receptacle 3 in order to add to the bath 4 additional material, for instance water which is recirculated from the user device and/or other already dispersed fibrous material of different type and characteristics than the fibers which are being introduced through the conduit 1, for example organic and/or inorganic fibers of different lengths or thicknesses. However, the ratio of fibers to liquid in the bath 4 should always be such that each fiber can individually move in the liquid.

It will be appreciated that it is fully within the concept of the present invention-and particularly desirable if a large fiber quantity is to be processed per unit of time to employ several conduits 8 each of which discharges a liquid stream 9 with all of these liquid streams intersecting the stream 2, but from different directions, so that the liquid streams are inclined to one another. This is diagrammatically indicated by the chain line 8a. It is hardly necessary to emphasize in this context that the arrangement may also be such that the stream 2 is discharged to the center of the intersection of the two or more streams 9.

FIGS. 2 and 3 show such a modified embodiment. Like reference numerals in these figures indicate elements corresponding to similarly numbered ones in FIG. 1. However, here it will be seen that two additional fiber supply channels are provided through which two additional streams of carrier gasdesignated 2a and 2b and carrying vitreous fibers-are admitted into the space of receptacle 3, again above level 5. In this embodiment the three streams 2, 2a and 2b enter from different directions (compare also FIG. 3). Furthermore, the angle included between stream 2a and the stream of liquid 9a issuing from the associated liquid conduit 8a, differs from the corresponding angles included between the stream 2 and the liquid issuing from conduit 8, and between the stream 2b and the liquid issuing from the associated conduit 8b. Note, however, that the liquid stream 9a also intersects the stream 2b.

As illustrated, each of the streams 2, 2a and 2b may be supplied with fibers from a separate fiber supply, and in turn these may each be fed by a separate producing device; similarly, each conduit 8, 8a and 8b may have its own liquid supply. It is, however, also conceivable to supply all streams 2, 2a and 2b from a single supply station and asingle producer, and to provide a single supply for the conduits 8, 8a and 8b. Such a determination is readily within the purview of those skilled in this art.

Insofar as the relative velocity of the fiber-air streams and the liquid streams is concerned, as well as the location in space at which they must intersectrelative to the level 5the comments made about the embodiment of FIG. 1 are fully applicable here.

In FIGS. 2 and 3, we have provided agitating means for the bath 4 in the region of its level 5, in form of a conduit 8d which communicates with the bath 4 slightly below level 5 and through which additional liquid may be admitted in a manner requisite for stirring bath 4 at least in the region of level 5. Of course, this liquid could also have been withdrawn from the bath at another location and be recirculated into the bath through conduit 8d.

For purposes of clarity it is pointed out that here also the water-fiber dispersion passes via the channel 6 and the breast box 7 into the user device in form of a not specifically illustrated but conventional fiber-forming apparatussuch as the one shown by way of example in FIG. 1-in which the fibers flow against a lip delimiting the deposition surface of an e.g. screen-type conveyor belt. In known manner the belt will pass over de-watering chambers in which the liquid, such as water wherein the fibers were dispersed, is largely withdrawn from the layer of fibers deposited on the surface of the belt. This liquid is recirculated, for intance via the conduits 8 and 12 and the receptacle 10. The diagrammatic sectional view of FIG. 3 shows that in lateral direction the channel 6 communicating with the bath 4 advantageously diverges from the width of receptacle 3 to the greater width of breast box 7 in diffuser-like manner. This is, incidentally, also advantageous in the FIG. 1 embodiment.

The method and apparatus according to the present invention can advantageously be used to supply into the bath 4 not only already dispersed but dry fibers of different type, for instance different length and/or thickness, via a stream of gaseous carrier fluid. In this manner, also, the structure of the finished fibrous sliver can be infinenced, for instance its porosity, its hand, its absorption characteristics, its flexibility or its weight per square meter. For this purpose it is for instance possible to use one of the additional conduits which communicate with the receptacle 3 and which carry the streams 2a and 2b. The additional fibers provided by this additional gaseous carrier stream may be so directed as to be inserted into the bath 4 in the manner previously discussed, either by the stream 9 and/or by the liquid stream discharged from whichever conduits 8, 8a or 8b may be provided.

It is emphasized that other possibilities and modifications of the present invention will offer themselves readily to those skilled in the art and are fully intended to be encompassed within the concept and scope of the present invention. Thus, it should only be pointed out by way of example that the additional fiber-supplying channels could also all discharge into the receptacle 3 on the same level as the channel 1. Also, it or they need not discharge from another side than the conduit 1, but all or some of them could discharge at the same side as the conduit 1 at a different level from the same.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a method and arrangement .for processing fibers of vitreous material, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without (further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a method of processing fibers of vitreous material, particularly glass, the steps of maintaining a liquid bath containing in dispersion a predetermined ratio of vitreous fibers; continuously withdrawing a predetermined quantity of liquid and fibers for supply to a user device; continuously blowing into a space located above and open to the upper level of said bath at least one stream of carrier gas at an angle smaller than with reference to a vertical on said upper level of said bath, said stream of carrier gas carrying vitreous fibers for replenishing those withdrawn from said bath; and continuously directing into said space and towards said upper level at an angle which is also smaller than 90 relative to a vertical on said upper level at least one stream of liquid intersecting said stream of carrier gas and having a cross-sectional area smaller than the surface area of said bath exposed to said space, and a velocity greater than that of said stream of carrier gas and so selected as to straighten and accelerate the fibers in said stream of carrier gas sufficiently to insert them into said bath and depress them below said upper level thereof.

2. In a method as defined in claim 1; further comprising the step of directing into said space at least one additional stream of liquid similar to the first-mentioned one and intersecting said stream of carrier gas from a different direction.

3. In a method as defined in claim 1; further comprising the step of blowing into said space at least one additional stream of carrier gas similar to the first-mentioned stream of carrier gas and carrying some of said fibers for replenishing those withdrawn from said bath; and wherein said stream of liquid intersects both of said streams of carrier gas.

4. In a method as defined in claim 1; and further comprising the step of agitating said bath so that the liquid thereof moves at said upper level with a speed which at least equals the speed of fibers being inserted into said bath by said stream of carrier liquid.

5. In a method as defined in claim 4, wherein the speed at which the liquid of said bath moves at said upper level is greater than the speed of said fibers being inserted into said bath.

6. In a method as defined in claim 1; and comprising the step of admitting additional liquid into said bath at least substantially free of pressure, for replenishin in part the liquid withdrawn from said bath.

7. In an apparatus for processing vitreous fibers, particularly glass fibers, in combination, container means accommodating a bath of liquid and vitreous fibers dispersed in predetermined ratio therein, said container means defining above the level of said bath an enclosed chamber which is open to said bath; outlet means for continuous withdrawal of liquid and fibers from said bath; supply means communicating with said chamber for continuously admitting into the same at a lower velocity and at an angle smaller than 90 relative to a vertical on said upper level of said bath at least one stream of carrier gas carrying fresh fibers for replenishing those withdrawn from said bath; and means for directing into said chamher at least one stream of liquid intersecting said stream of carrier gas in direction towards and also at an angle smaller than 90 relative to a vertical on said upper level of said bath and at a higher velocity so selected as to straighten said fibers and depress them below said level into said bath.

8. In an apparatus as defined in claim 7, including additional means for directing into said chamber at least one addition stream of liquid similar to the first-mentioned stream of liquid but intersecting said stream of carrier gas from a different direction.

11 12 9. In an apparatus as defined in claim 7, including an 2,658,848 11/1953 Labino 162-456 additional means for admitting into said chamber at least 3,293,116 12/ 1966 Opderbeck 162156 one additional stream of carrier gas and fibers, said 3,691,009 9/ 1972 Opderbeck et al. 162157 X stream of liquid also intersecting said additional stream 3,676,294 7/1972 Opderbeck et al. 162380 X of carrier gas and fibers. 5

S. LEON BASHORE, Primary Examiner References Cited R. H. TUSHIN, Assistant Examiner UNITED STATES PATENTS 2,787,542 4/1957 Labino 162--156 3,021,255 2/1962 Simpson 162-336

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