US3787195A

US3787195A - Apparatus for the production of sheets or mats from fibers of thermoplastic material

Info

Publication number: US3787195A
Application number: US00136132A
Authority: US
Inventors: J Kirchheim
Original assignee: Compagnie de Saint Gobain SA
Current assignee: Compagnie de Saint Gobain SA
Priority date: 1970-04-29
Filing date: 1971-04-21
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22
Also published as: DE2118081A1; GB1359003A; NO129342B; RO63891A; SE370384B; FR2108162A2; FR2085525B1; GB1359001A; DK141400B; FI52967C; DE2118081B2; JPS5145704B1; NL166290C; HU166151B; ES390691A1; NL166290B; BE766432A; NL7105438A; FI52967B; BR7102534D0

Abstract

The invention concerns the production of homogeneous and structurally resistant sheets or mats of thermoplastic fibers, such as glass fibers, issuing from one or more spinnerettes above a travelling conveyor. The fibers are deposited on the conveyor after being blown through a stationary skirt or conduit formed essentially of a pair of large plane surfaces having critically controlled spacings therebetween to attain predetermined crosssectional areas between the inlet and outlet end of the conduit, as well as adjustable outlines of the outlet. These variable and/or adjustable sectional areas serve to control the pattern and area of deposition of the fibers on the conveyor. A plurality of spinnerettes and guide conduits may be arranged in different patterns and alignments relative to the direction of travel of the conveyor to control the laying-up of the fibers and consequently the physical characteristics of the deposited mat. Additional trapezoidally shaped shaping members, also each formed essentially of a pair of large plane surfaces with an inlet and outlet, as well as intermediate sections of predetermined or adjustable areas, may be used in lieu of or in conjunction with the above-mentioned skirts or conduits. These shaping members are fitted with openings and/or blowers for air or gaseous currents to afford a convenient control of the entrainment of the dropping fibers passing therethrough, which discharge from the outlet ends of said members, which are spaced a slight distance above the travelling conveyor.

Description

United States Patent [1 1 Kirchheim Jan. 22, 1974 APPARATUS FOR THE PRODUCTION OF SHEETS OR MATS FROM FIBERS OF THERMOPLASTIC MATERIAL [75] Inventor: Jean-Jacques Kirchheim,

Saint-Maur-des-Fosses, France [73] Assignee: Saint-Gobain, Neuilly-Sur-Seine,

France 22 Filed: Apr. 21, 1971 21 Appl. No.: 136,132

[30] Foreign Application Priority Data Primary Examiner-Robert L. Lindsay, Jr. Attorney, Agent, or Firm-Dale A. Bauer; John L. Seymour; Bauer & Seymour Samuel Lebowitr [57] ABSTRACT The invention concerns the production of homogeneous and structurally resistant sheets or mats of thermoplastic fibers, such as glass fibers, issuing from one or more spinnerettes above a travelling conveyor. The fibers are deposited on the conveyor after being blown through a stationary skirt or conduit formed essentially of a pair of large plane surfaces having critically controlled spacings therebetween to attain predetermined cross-sectional areas between the inlet and outlet end of the conduit, as well as adjustable outlines of the outlet. These variable and/or adjustable sectional areas serve to control the pattern and area of deposition of the fibers on'the conveyor. A plurality of spinnerettes and guide conduits may be arranged in different patterns and alignments relative to the direction of travel of the conveyor to control the laying-up of the fibers and consequently the physical characteristics of the deposited mat. Additional trapezoidally shaped shaping members, also each formed essentially of a pair of large plane surfaces with an inlet and outlet, as well as intermediate sections of predetermined or adjustable areas, may be used in lieu of or in conjunction with the above-mentioned skirts or conduits. These shaping members are fitted with openings and/or blowers for air or gaseous currents to afford a convenient control of the entrainment of the dropping fibers passing therethrough, which discharge from the outlet ends of said members, which are spaced a slight distance above the travelling conveyor.

17 Claims, 30 Drawing Figures PATENTEDJANZZIW 3.787. 195

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SHEET OZUF 11 PATENIEUJANPPIETM SIEEI 03UF 11 PMENTH] JAN 2 2 1974 SHEET 0% HF 11 mwdm PAIENTED JAN 2 2 m;

SHET 05 0F 11 PATENTED 3,787, 195

SHEET UEUF 11 PAIENTED JAN 2 21974 SHEET 070F 11 PATENTED JAN 2 21974 SHEEF DSUF 11 PATENTED 3.787. 195

SNEEI IOUF 11 APPARATUS FOR THE PRUDUCTHON OT SHEETS OR MATS FROM IFTBERS F THEUPLASTH MATIEIRTAL The present invention relates to apparatus for, the production of sheets or mats from fibers of thermoplastic materials, particularly glass fibers produced by a drawing plate or spinning nozzles, and which are entrained by gaseous currents onto a perforated conveying member, below which is disposed a suction box.

According to a known device, a feeder or bushing with a drawing plate is used, the orifices of which are arranged horizontally and in parallel rows in the direction of movement of the conveying member. A blower is disposed below this drawing plate, in proximity with and parallel thereto, for delivering a gaseous fluid under pressure, such as air or steam, which acts by induction on the filaments of molten material, in order to transform them into fibers by separating and attenuating them. This blower is integrally connected at its lower end with a sleeve having vertical walls of rectangular section, known also as a fixed hood or skirt, which is adapted to channel the gaseous jet and the produced fibers toward the conveyor member.

As is known, the device described above may be completed advantageously by two rectangular plates located symmetrically on both sides of the jet of fibers in the direction of the conveyor member, each being movable about a horizontal axis, parallel to the direction of the movement of the conveyor, with each axis being also coincident with the upper edge of the respective plate. These plates, which may also be designated movable deflectors, are actuated by a synchronized oscillating movement, at a frequency of 240 to 600 pulsations per minute, and with such an angular amplitude that the oscillations transmitted to the jet of fibers effect the distribution of the latter over the entire width of the conveyor. When two or more fiberproducing devices such as the above are used and are placed side by side in a direction transverse to that of the movement of the conveyor, each of the movable deflectors is activated in synchronism, but with a phase lag, in such a way that at each instant the different jets of fibers are combined on the conveyor member.

It is the object of the present invention to improve equipment of the type described above, by virtue of which sheets, pads or mats of fibers are obtained having a high degree of homogeneity, while dispensing with the use of movable distributing members.

In accordance with the invention, the fiber drawing plate or plates disposed above the conveyor, are provided below the level of the blower members, which effect the drawing-out of the fibers, with skirts or conduits comprising two large surfaces of generally flat shape, the planes of which converge in the direction of travel of the gaseous fluid and are symmetrical with respect to the principal axis of said skirts. The latter have an outlet opening of a cross-section at least equal to that of the inlet opening, to channel the gaseous fluid, as well as the air or induced fluid, so as to disperse the entrained fibers and to effect their uniform distribution on the conveyor member. It has been determined that by virtue of the use of such skirts, the drawing-out of the filaments of material by fluid through the skirts, is accomplished in a uniform menner without the threads having a tendency to bend their direction toward the center and recede from the edges of the skirts in the course of effecting the regrouping of the fibers. The

result is that the fibers produced at the outlet of the skirt constitute a homogeneous assembly, which leads to uniform distribution of the fibers on the conveyor member.

According to another characteristic of the invention, the skirts are furnished with selective clamping means which permit a modification of the shape of the crosssection of the outlet passage, to control the flow and direction of the gaseous jets entraining the fibers, and consequently the distribution of said fibers on the conveyor member. These clamping or tightening means may be constituted by screws or threaded bolts acting separately on the lower part of each large base of the skirt, which are screwed against a stationary part independent of the skirt. For example, if the opening at the outlet of the skirt is reduced to a maximum extent by tightening, with the two large edges of this outlet opening remaining substantially parallel, the resulting jet of fibers is spread out greatly, which at the level of the conveyor, covers a great distance. If, on the other hand, the clamping is so regulated as to obtain a considerable opening at the parallel edges, it is found that the path of the sheaf or bundle of fibers on the conveyor is much shorter, its length being of the order of that of the drawing-plate itself. If intermediate adjustments are made, such as tightening of the outer screws and loosening of the central screws, a sheaf is obtained having a path on the conveyor which approximates a circular form. In the case where the outer screws are loosened and the central screws are tightened, there results a division of the jet in two, with the fibers separating on the conveyor into two parts. In like manner, by appropriate adjustment of the clamping screws, jets of fibers of different sections and directed toward any part of the conveyor may be obtained.

According to another characteristic of the invention, the drawing plate or spinnerette, the blower and the accompanying fixed skirt, are placed transversely relative to the direction of movement of the conveyor. By virtue of the adjustable outlet of the skirt, it is possible to spread out the jet of fibers in a uniform manner over the entire width of the conveyor, which operation, combined with the advance of the conveyor, gives rise to the production of homogeneous sheets of fibers. Consequently, the skirts with an adjustable outlet makes possible the elimination of the movable deflectors which are used in known apparatus.

It is advantageous, and this is another characteristic of the invention, to design the skirts with such a profile that at least the whole width of the conveyor is visible from each orifice of the drawing plate through the passage of the blower and the skirt.

According to another characteristic of the invention, it is advantageous to use two or more devices according to the invention, placed side by side on a common axis parallel to the direction of the movement of the conveyor. In this way each device produces an elemental sheet of the width of the conveyor, the elemental sheets being superposed one on the other without disturbing in the least, the distribution of the fibers. Thereby is eliminated the presence of wicks and tufts of fibers in the finished products.

According to another interesting characteristic of the invention, the directional effect of each of the skirts is regulated in such a way that each of the spinnerettes affects only one zone of the conveyor member, so that the assembly of these skirts effects a homogeneous distribution of the fibers over the entire surface of the conveyor.

According to another characteristic of the invention, the apparatus may comprise a shaping member discharging in proximity to the conveyor member and having two large surfaces of generally plane shape, converging at least at one portion of their length in the zone near the outlet section. This shaping member may be placed immediately below the level of the blower which effects the drawing-out of the fibers, with the skirts or conduits according to the invention forming an integral part with the two large plane surfaces of this shaping member.

The invention also contemplates the positioning of the shaping member immediately below the level of the skirts or conduits in accordance with the invention described above, with air induction being attained inside the shaping member between the outlet of the skirts or conduits and the inlet of said shaping member.

According to another characteristic of this invention, the control of the regularity, the quantity, as well as the decrease of speed of flow of the gaseous fluid entraining the fibers in the shaping organ, is effected by the conjugate action of the variation of the section of this shaping organ and the introduction of additional fluids.

According to another characteristic of the invention,

the means provided for the introduction of additional fluids are placed and regulated in such a way that the quantity of fluid per unit of area remains substantially constant across all the transverse sections of the shaping member.

Other objects, characteristics and advantages of the invention will appear from the following description thereof as embodied in several illustrative physical forms shown in the accompanying drawings wherein,

FIG. 1 is a perspective view of a device according to the invention, at the upper portion of the apparatus;

FIG. 2 is a vertical sectional view of the skirt and its regulating members, along a longitudinal plane transverse to the axis of the drawing plate;

FIG. 3 is a front elevation of the apparatus for producing a sheet of fibers over the entire width of the conveyor;

FIG. 3a is a bottom view of the outlet slotofthe skirt;

FIG. 4 is-an end view of the apparatus showing two devices placed one after the other in the direction movement of the conveyor member;

FIG. 5 is a front elevation of the apparatus, so adjusted as to produce a sheet of fibers over half of the width of the conveyor;

FIG. 5a is a bottom view of the outlet slot of the skirt shown in FIG. 5; Y

FIG. 6 is a front elevation of the apparatus, so ad justed as to produce a sheet of fibers on the other half of the width of the conveyor; 1

FIG. 6a is a bottom view of the outlet slot of the skirt shown in FIG. 6;

FIG. 7 is an end view showing two successive devices projecting the fibers over one half of the width of the conveyor, and the other half, respectively, in order to obtain a uniform deposit over the entire breadth of the conveyor;

FIG. 8 is a front elevation of the apparatus so adjusted as to produce a deposit of fibers of circular form on the conveyor;

FIG. 8a is a bottom view of the outlet slot of the skirt shown in FIG. 8;

FIG. 9 is an end view showing two successive devices each producing a circular shaped deposit, these devices being staggered transversely in the direction of travel of the conveyor;

FIG. 10 is a front elevation of an apparatus producing two distinct jets of fibers;

FIG. 10a is abottom view of the outlet slot of the skirt shown in FIG. 10;

FIG. 11 is an end view showing two devices, one of which produces two distinct jets of fibers, and the other one, a single jet of fibers in the space between the preceding ones;

FIGS. 12 to 15, on the first sheet of the drawings, with FIG. I, are schematic plan views of distribution of the devices above the conveyor;

FIG. 16 is a schematic front view of another embodiment of the invention;

FIG. 17 is a vertical sectional view of FIG. 16 through a plane perpendicular to the axis of the drawing plate;

FIG. 18 is a vertical sectional view, similar to FIG. 17, of a variant from the apparatus shown in FIG. 16;

FIG. 19 is a perspective view of another embodiment of the invention;

FIG. 20 is a vertical sectional view of FIG. 19, through a plane perpendicular to the axis of the drawing plate or spinnerette;

FIG. 21 is a front view of still another embodiment of the invention;

FIG. 22 is a vertical sectional view of FIG. 21 along a plane perpendicular to the axis of the drawing plate or spinnerette;

FIG. 23 is a vertical sectional view, similar to FIG. 22, of a variant of the apparatus shown in FIG. 22;

FIG. 24 is a front view of another embodiment of the invention; and

FIG. 25 is a vertical sectional view of FIG. 24, through a plane perpendicular to the axis of the spinnerette.

In FIG. 1 of the drawings is shown the body 1 containing a mass of molten glass. A row 3 of spinning nozzle orifices is disposed below the chamber 1. In this figure is also shown the skirt 4, the upper opening of which is opposite the row of orifices 3 of the spinnerette and which empties into the casing 5 communicating with a source of fluid under pressure. The outlet slot of the skirt is shown at 12. The large surfaces of the skirt are trapezoidal in shape and converge towards the enlarged base of the skirt. Frame supports 6 are affixed to the casing 5, and adjusting screws 10 are mounted on the former for acting on surfaces 11 of the skirt. The mounting details of the regulating screws 10 are shown in FIG. 2. Internally threaded bores in vscrews 10 are engaged with threaded rods 7 which act on the surfaces 11 of the skirt through articulated joints 8. In this figure are also shown the opposed openings 9 through which the gaseous fluid admitted into the casing 5 is introduced into the skirt 4, on opposite sides of the curtain of filaments issuing from the spinnerette.

As shown in FIGS. 35 and 3a, the adjusting screws ll) acting on the lower part of the surfaces 11. of the skirt are regulated so that outlet slot 12 is of constant width. The sheet 13 of projected fibers is deposited on conveyor M along its entire breadth, said conveyor moving continuously in the direction perpendicualr to the rows of orifices of the spinnerette. lBy regulating the screws, slots of greater or smaller width may be obtained, which permits the obtention of sheets of greater or lesser thickness.

It is possible, as shown in FIG. 4, to group several devices 15 of the type described above, so that their axes x-x are in the common vertical plane passing through the median longitudinal plane of the conveyor. Thereby, the thickness of the deposited fibers formed on the latter becomes greater as the number of devices 115 is larger.

By regulating screws Ill so that slot 12 has a width decreasing progressively from one extremity to the other, as shown in FIGS. 5 and 5a, the fibers from device 15 are projected along a sheet 13 involving only one part of the surface of the conveyor. This regulation can be effected so that the deposit of fibers on conveyor 14 takes place only on half the width of the latter. In this case, a second device 115a (FIGS. 6 and 7), may be used, which may be positioned following and in line with the first, and the outlet slot 312a of which has the same shape as that of the preceding device 15, but with its width diminishing in an inverse ratio as indicated in FIG. 6a, so as to effect a deposition of the fibers in the form of a curtain of fibers 13a, on the other half of the width of the conveyor. Thus, by the use of two devices 15, 15a, whose outlet slots 12, 12a have, respectively, the shapes shown in FIGS. 5a and 6a, a homogeneous deposit of fibers, in the form of

curtains

13 and 13a, over the entire surface of the conveyor is obtained.

FIG. 8 illustrates a device 115 with a skirt having regulating screws 10 which may be adjusted in such a way that the outer screws are tightened while the median screw is loosened to form a slot 12 having the shape shown in FIG. 8a. Thereby, a sheaf of fibers 113 is obtained, the projection of which on the conveyor 14 approximates a circular form.

As shown in FIG. 9, several devices 15, 15a, of the type described in the preceding paragraph, may be associated successively with the conveyor, each producing a deposit of fibers in substantially circular form on the conveyor, by similar adjustments of screws 10, 10a. Such a grouping of the devices effects a deposition of a homogeneous sheet of fibers across the whole width of the conveyor.

FIG. 10 illustrates a device 15 with the skirt having regulating screws 10 which permit the outer screws to be loosened while the median screw is tightened. Slot 12 then has the form shown in FIG. 10a. This shape of slot permits obtaining two jets of

fibers

13, 13a diverging from one another and oriented toward the sides of the conveyor. In order to obtain a homogeneous deposit of fibers on the conveyor, a second device 15a may be associated with this device 15, as indicated in FIG. 11, such as, for example, a device whose screws may be adjusted as shown in FIG. 8a, to produce a jet of fibers 13a directed toward the middle of the conveyor.

In order to effect the sizing of the fibers deposited on the conveyor band, spray guns or weirs may be provided downstream from the point of formation of the sheet on the conveyor for applying a composition to the fibers.

The schematic diagrams shown in FIGS. 12 to 15, on the first sheet of the drawings, illustrate by way of example, different arrangements for distributing the devices 15 above conveyor 14. In the arrangement of FIG. 12, the devices 15 are abreast of each other with respect to the direction of movement of the conveyor. In the arrangement of FIG. 13, the devices are in a quincuncial pattern. With these arrangements the formation of wicks is avoided, while obtaining sheets or pads of large widths. In the arrangement of FIG. 14, the devices are in a single file or line with respect to the direction of travel of the conveyor. The formation of cores or wicks is avoided, while also multiplying the number of layers formed on the conveyor. The homogeneous distribution of the fibers on the conveyor is obtained by suitable clamping expedients imposed on the skirts, as described above. According to the arrangement shown in FIG. 15 the devices 15 are disposed abreast of each other with respect to the direction of movement of the conveyor as well as with their large axes parallel to the latter. This arrangement also results in the elimination of wicks and obtaining sheets or mats of large width.

By way of example, the half-angle a at the top of the large trapezoidal surfaces 11, as shown in FIG. 3, may be given a value of about 15. Furthermore, these large surfaces may be toed-in or caused to converge before any regulation; for example, the spacing between these surfaces at the inlet end at the top may be about 7mm., and at the outlet end at the bottom, 5.4mm.

In FIGS. 16 to 18 is shown a shaping member, designated generally by reference character 17, which discharges in proximity to the conveyor 14. This shaping member 17 comprises two

large surfaces

18 and 19 of generally plane shape. In the embodiment illustrated in FIG. 17, these two large plane surfaces 18 and 19 converge along a part of their length located in the zone adjacent to the outlet section. These convergent parts are designated by

reference characters

18' and 19. On the other hand, in the embodiment shown in FIG. 18, the two

large surfaces

18 and 19 of the shaping member are convergent over their entire length. The shaping member, in the embodiments illustrated in FIGS. 16 to 18, is placed immediately below the level of the blower members 5, which effect the drawing-out or attenuation of the fibers, with the skirts or conduits described above constituting an integral part of the two

large surfaces

18 and 19 of the shaping member 17.

In the embodiment illustrated more completely in FIGS. 19 and 20, the shaping member 17 is placed immediately below the level of the skirts or conduits described above and indicated schematically at 4. The shaping member is constituted by an elongated skirt whose two large plane surfaces 18 and 19 are trapezoidal in shape. In this embodiment, these two large plane surfaces are convergent over their entire height (FIG. 20)., but, as described above, these two large plane surfaces may converge along only part of their length, namely, along the part near the outlet section 20. In order to regulate the available cross-sectional area for the passage of gaseous fluid bearing the fibers, clamping means are provided, which may assume the form of screw 21, in engagement with threaded rods 22, which act on the large faces of the shaping member 17 suitable sizing by means of connectors which, in this example, are constituted by angle irons 23. The sheet of fibers projected through the shaping member 17 is deposited on the conveyor member 14, which is moved continuously in the direction perpendicular to the rows of orifices of the spinnerette. An induction of air takes place on the inside of the shaping member, between the outlet of the skirts or conduits 4, and the intake 25 of said shaping member.

According to the invention, the control of the regularity, quantity and decrease of speed of flow of the gaseous fluid entraining the fibers is effected by the cooperative action between the variation of the crosssection of the shaping member 17 and the introduction of additional fluids. As noted above, in the embodiment shown in FIGS. 19 and 20, the introduction of additional fluids was realized in the form of induced air.

According to the invention, this introduction is controlled in such a way that the quantity of fluid per unit of surface area remains substantially constant through all the transverse sections of the shaping member.

The cross-section of the opening may be varied by operating the clamping means so as to obtain a volume of induced air from eight to times the volume of the gas leaving the skirt conduit. The outlet section 20 and inlet section of the shaping member are also regulated in the same manner so that the area of the outlet section 20 is of the order of one to two times that of the inlet section 25.

With a view of obtaining better results in respect to the homogeneity of the distribution of fibers on the conveyor member, it has been determined that the speed of the gaseous fluid bearing the fibers at the inlet 25 of the shaping member should advantageously be one to five times that at the outlet 20. By way of illustration, the following values have provenpractical:

Speed at inlet 25 75 meters per second Speed at outlet 20 25 meters per second Speed on conveyor 14 15 meters per second The embodiments of the invention illustrated in FIGS. 21 to 25 have for their objective the capability of introducing a volume of additional fluids either in the form of a controlled induction of air, or in the form of air or steam introduced by means of blower members in an amount corresponding to the increase in volume in the shaping member. This quantity of additional fluids should correspond to the increased crosssection of the shaping member between the flaring walls of the latter. Thereby is attained, over the entire height of the shaping member, a constant quantity of fluid per unit of surface at each section, and consequently a flow of reduced turbulence.

By referring to FIGS. 21 to 23, it is seen that the shaping member is of a design similar to that shown in the preceding figures, but it has openings, arranged here in the form of shutters 27, which are preferably regulatable, and which permit the induction of air. In this embodiment, the shutters 27 are placed on each of the large surfaces of the shaping member. In addition,

blower members

32,33 are provided and arranged in such a way as to introduce additional gaseous fluids into the shaping member. In the arrangement shown in FIGS. 21 to 23, one of these blowers 32 is shown positioned at the upper opening of the shaping member and a second blower 33 discharging over one of the shutters 27 at an intermediate level. It goes without saying that the number, position, and distribution of these blowers will be determined as a function of each particular case, in order to achieve the control conditions of the invention as set forth above.

It is to be noted that in the embodiment shown in FIG. 22, the large surfaces of .the shaping member are convergent only at 34, over a portion of their length near the conveyor 14, while that in FIG. 23, they are convergent over their entire length.

In the embodiment of the invention shown in FIGS. 24 and 25, the shaping member is constituted by sev-' eral superposed elements, such as 28, 29, between which air is induced. These elements have two large plane surfaces which converge over at least a portion of their length, at the portions thereof adjacent to their outlet. In the arrangement shown in FIG. 25, the large plane surfaces are shown convergent over their entire lengths. In accordance with the invention, the outlet 38 of one of the shaping members is lower than the intake 39 of the following member. In addition, the outlet section 40 of each member is at least equal to that of the intake section 39 of the same member.

In FIGS. 24 and 25 are shown

blower members

35 and 36 which are adapted to introduce gaseous fluids into the interior of the shaping member under the same conditions as set forth above. Blower 35 is positioned at the inlet of the shaping member and blower 36 is located between two successive elements at a lower level. Naturally, other blowers, similar to 36, may be provided at addtional levels.

The devices of the present invention have the particular advantage of avoiding the regrouping of the fibers and of spreading them on the conveyor without forming packs, bundles or nodules. They also make possible an improvement in the resistance of the sheet, for example, in the case of the embodiment shown in FIGS. 24 and 25, by a deformation and/or change of orientation of at least one of the successive elements of the shaping member, which gives rise to a preferential orientation of the fibers on the conveyor.

It should be understood that the invention is not limited to the specific embodiments shown and described above, since the objectives stated above may be realized with diverse variations. Thus, in particular, movable deflectors may be provided below the stationary skirts according to the invention.

The travelling conveyor 14 is illustrated in the several figures of the drawings only schematically. Its airpermeable characteristics may be realized by the use of perforated or woven sheets of metal, textile or composite fabrics, with preferably a suction box therebelow, as is known in the art.

I claim:

I. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor,

b. a blowing chamber below said nozzles for inducing gaseous currents to act on the opposite sides of the filaments gravitating from said nozzles to effect the attenuation thereof,

c. a stationary conduit below said blowing chamber comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said conduit,

d. a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member,

e. means defining openings along the length of said shaping member for controlling the induction of air into said shaping member,

f. said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end, and

g. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for uniform distribution thereof onto said travelling conveyor.

2. An apparatus as set forth in claim ll, including means for introducing additional gaseous fluids into said shaping member on at least one level thereof for controlling the entrainment of the fibers therethrough.

3. An apparatus as set forth in claim 2, wherein said last-mentioned means is provided at both the inlet and outlet levels of said shaping member.

4. An apparatus as set forth in claim 2, including means for modifying the cross-section of said shaping member between the inlet and outlet ends thereof, thereby to control the regularity, the quantity and the decrease in speed of the gaseous fluid entraining the fibers through said shaping member.

5. An apparatus as set forth in claim 4, including adjusting means for said shaping member to reduce'the speed of the gaseous fluid at the outlet end from one to five times that at the inlet end.

6. An apparatus as set forth in claim 4, including adjusting means for said shaping member to reduce the speed of the gaseous fluid at the outlet end of the shaping member to one-third that at the inlet end thereof.

7. An apparatus as set forth in claim 4, including adjusting means for said shaping member to adjust the cross-sectional area of the outlet end to render it approximately one to two times that of the inlet end.

8. An apparatus as set forth in claim 2, including means for adjusting said gaseous fluid introducing means into said shaping member to render substantially constant the quantity of gaseous fluid per unit of area passing the different cross-sectional areas along the length thereof in the course of flowing therethrough.

9. An apparatus as set forth in claim 2, wherein said last-mentioned means controls at least partly the introduction of air into the shaping member.

10. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor,

(1. a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member.

e. means below said inlet for introducing additional gaseous fluids into said shaping member for controlling at least partially the introduction of air into said shaping member and the entrainment of the fibers therethrough, comprising openings with shutter closures therefor, through which air is admitted into the interior of said member,

11. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor,

e. said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end,

f. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for uniform distribution thereof onto said travelling conveyor, and

g. said shaping member being constituted by a plurality of superposed elements spaced from each other by spacing gaps, said last-mentioned gaps providing passages for the entry of air into said shaping member.

12. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor,

a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member,

e. means below said inlet for introducing additional gaseous fluids into said shaping member for controlling at least partly the introduction of air into said shaping member and the entrainment of the fibers therethrough, said means in conjunction with the controlled spacing between the inlet of said shaping member and the outlet of said stationary conduit adapted to feed into said shaping member, approximately eight to times the quantity of gaseous fluid applied initially on the filaments issuing from the spinnerette to effect the attenuation thereof,

f.- said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end, and

g. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for unifonn distribution thereof onto said travelling conveyor.

13. An apparatus as set forth in claim 11, wherein said superposed elements are each provided with outlets terminating below the level of the inlet of the next lower element.

14. An apparatus as set forth in claim 13, wherein the outlet of each superposed element is of a cross-section at least no greater than that of the inlet of the next lower element.

15. An apparatus as set forth in claim 11, including 1 at least one blower unit between two of the superposed elements to induce additional gaseous fluids into said shaping member.

16. An apparatus as set forth in claim 11, including means for adjusting the outline of at least one of said superposed elements with respect to the adjacent one to control the deposition of the fibers on the travelling conveyor.

17. An apparatus as set forth in claim 11, including means for adjusting the orientation of at least one of said superposed elements with respect to the adjacent one to control the pattern of the deposition of the fibers relative to the travelling conveyor.

Claims

1. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor, b. a blowing chamber below said nozzles for inducing gaseous currents to act on the opposite sides of the filaments gravitating from said nozzles to effect the attenuation thereof, c. a stationary conduit below said blowing chamber comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said conduit, d. a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member, e. means defining openings along the length of said shaping member for controlling the induction of air into said shaping member, f. said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end, and g. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for uniform distribution thereof onto said travelling conveyor.

2. An apparatus as set forth in claim 1, including means for introducing additional gaseous fluids into said shaping member on at least one level thereof for controlling the entrainment of the fibers therethrough.

5. An apparatus as set forth in claim 4, including adjusting means for said shaping member to reduce the speed of the gaseous fluid at the outlet end from one to five times that at the inlet end.

10. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor, b. a blowing chamber below said nozzles for inducing gaseous currents to act on the opposite sides of the filaments gravitating from said nozzles to effect the attenuation thereof, c. a stationary conduit below said blowing chamber comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said conduit, d. a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member, e. means below said inlet for introducing additional gaseous fluids into said shaping member for controlling at least partially the introduction of air into said shaping member and the entrainment of the fibers therethrough, comprising openings with shutter closures therefor, through which air is admitted into the interior of said member, f. said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end, and g. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for uniform distribution thereof onto said travelling conveyor.

11. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that the fibers experience a free drop before deposition on said conveyor, b. a blowing chamber below said nozzles for inducing gaseous currents to act on the opposite sides of the filaments gravitating from said nozzles to effect the attenuation thereof, c. a stationary conduit below said blowing chamber comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said conduit, d. a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member, e. said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end, f. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for uniform distribution thereof onto said travelling conveyor, and g. said shaping member being constituted by a plurality of superposed elements spaced from each other by spacing gaps, said last-mentioned gaps providing passages for the entry of air into said shaping member.

12. An apparatus for producing mats of thermoplastic material, comprising a. a spinnerette for said material in a molten state comprising a chamber for the material with at least one row of nozzles in the bottom thereof wherefrom flow downwardly filaments of the molten material toward a travelling conveyor therebelow and spaced a substantial distance therefrom so that tHe fibers experience a free drop before deposition on said conveyor, b. a blowing chamber below said nozzles for inducing gaseous currents to act on the opposite sides of the filaments gravitating from said nozzles to effect the attenuation thereof, c. a stationary conduit below said blowing chamber comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said conduit, d. a shaping member below said stationary conduit having the inlet thereof spaced from the latter to permit the induction of air into said member, e. means below said inlet for introducing additional gaseous fluids into said shaping member for controlling at least partly the introduction of air into said shaping member and the entrainment of the fibers therethrough, said means in conjunction with the controlled spacing between the inlet of said shaping member and the outlet of said stationary conduit adapted to feed into said shaping member, approximately eight to 10 times the quantity of gaseous fluid applied initially on the filaments issuing from the spinnerette to effect the attenuation thereof, f. said shaping member comprising a pair of large plane surfaces of symmetrical outline with respect to the vertical axis of said member, having a slight convergence at least adjacent to the outlet end thereof, while the cross-section of the outlet end is at least as great as that of the inlet end, and g. said outlet end being disposed in proximity to said travelling conveyor but in spaced relation thereto to disperse the fibers from said outlet end for uniform distribution thereof onto said travelling conveyor.

15. An apparatus as set forth in claim 11, including at least one blower unit between two of the superposed elements to induce additional gaseous fluids into said shaping member.