BE894826A - PROCESS AND APPARATUS FOR MANUFACTURING CUT AND TABLET STRANDS - Google Patents

Description

       

  "Method and apparatus for making cut and compressed strands" Method and apparatus for making cut and compressed strands.

  
The present invention relates to a method and apparatus for manufacturing high density cut and compressed strands. More particularly, the invention relates to a method and an apparatus for manufacturing cut and compressed strands practically in the form of bars from cut strands having a generally flat shape, which is obtained by cutting a strand of long fibers, by for example, a strand or strand of glass fibers.

  
In recent years, glass fiber reinforced thermoplastics have been widely used as part materials to be of high mechanical strength.

  
Various processes are known for the manufacture of articles from these thermoplastic materials reinforced with glass fibers.

  
According to one of these known methods, by means of an extruder, a mixture of pellets of a thermoplastic resin and strands cut from glass fibers is transformed into pellets, then the pellets thus formed containing glass fibers are shaped. into an article using an injection molding machine. According to another known method, the mixture of strands cut from glass fibers and pellets

  
resin is loaded directly into an injection molding machine by which it is shaped into an article.

  
In these processes, the unit or all of the cut strands is an important factor which largely influences different operating characteristics, as well as the formability during the stages of preparation of the mixture of resin pellets and cut strands, as well than during the final forming step, this factor also influencing different physical properties of the formed article. In particular as a result of cracks, fluffing and separation of the cut strands, not only the operating characteristics and the formability are altered during these stages, but it is also difficult to obtain different characteristics. strength and other physical properties such as the homogeneity of the formed article.

  
On the other hand, in the field of manufacture of glass fiber reinforced thermoplastic articles, there is a trend towards labor saving, rationalization and systematization, which, in turn , requires a certain change in the shape of the strands cut from glass fibers.

   In this case, until now, the length of the glass fibers used for the manufacture of thermoplastic articles reinforced with glass fibers has generally been between 3 and 6 mm but, recently, more and more strands have been requested. shorter cuts having, for example, a length of 1 to 3 mm, as well as a higher integrity and a higher density in order to ensure the operating characteristics and to fully exploit the possibilities of machines such as automatic machines for weighing, pneumatic conveyors, etc. which is used to meet the demands for labor savings, rationalization and systematization.

   It should also be noted that there is an increasing demand for homogenization and equalization of the thermoplastic articles themselves reinforced with glass fibers, since both the use of articles of this type extends to the field of small parts. These requirements also increase the demand for shorter, denser cut strands.

  
In this regard, conventional cut strands pose a vital problem. In this case, following

  
prior art, flat strands are obtained due to the characteristics of the forming process and depending on the requirements of the cutting process; however, this flat shape considerably alters not only the operating characteristics during automatic weighing and pneumatic transport, but also the formability. More specifically, in the conventional process for forming glass fibers, glass filaments from a sleeve or an orifice plate forming part of a spinning furnace, they are collected in strands and they are wound on coils under a high tension which is necessary to form filaments and overcome the friction force resulting from contact with a primer applicator, collector pads, a cross member, etc.,

   so that the strands wound on the coils inevitably have a flattened cross section, The strands wound are dried into cakes. The strands of the dried cakes are then cut. Immediately before cutting, a lubricant or an aqueous coating agent is applied to the cake. However, these steps do not significantly modify the flat configuration of the strands.

  
The same remark also applies when an undried cake is cut directly or when an aqueous dressing agent is applied secondarily to the undried cake before cutting.

  
Another process is known for forming cut strands, that is to say a cutting process.

  
direct type, during which strands coming. from a spinning oven are brought directly to a device which cuts them. In this case, the stretching tension of the fibers is created by the adhesion of the strand to a peripheral surface of a supply roller of the cutting device, a roller on which the fibers are inevitably flattened. As a result, the cut strand has, of course, a flat configuration. Strands of this type having a flat cross section have a large specific surface area and are generally bulky as a whole.

   Consequently, the operating characteristics during the automatic weighing and the pneumatic transport involved in the forming process, as well as the operating characteristics during the stage of preparation of the mixture with pellets of a resin are disadvantageously altered, the flattened cross section of the strand in itself reduces resistance to external mechanical forces, while disadvantageously increasing the tendency to fluff, cracking and separation, which further impairs operating characteristics and formability .

  
A cut strand is obtained by gathering a large number of filaments (for example, 800 to 2,000 filaments) into a strand which is then cut into other strands of a predetermined length. Yes

  
the cut strands are shorter, the impact force exerted by the cutting device increases relative to the bonding force. The resistance of the cut strand to mechanical external forces is also reduced.

  
It is therefore an object of the present invention to provide a method and an apparatus for manufacturing cut and compressed strands having a higher density and hence better unity and resistance to external mechanical forces compared to strands. classic cuts having a flattened cross section.

  
To this end, according to one aspect of the invention, a method of manufacturing cut and compressed strands is provided, this method comprising the steps consisting in preparing flattened cut strands and subjecting them to a rolling effect while they are still wet, so as to compress them,

  
According to another aspect of the invention, there is provided an apparatus for the manufacture of cut and compressed strands, this apparatus comprising a rolling apparatus having an inlet intended to receive cut and impregnated strands, a rolling element exerting a rolling effect on these cut and impregnated strands so as to compress them, as well as an outlet for removing the cut strands which have been treated.

  
According to a preferred embodiment of the invention, a rolling effect is exerted on the cut and flattened strands by vibrating a plate supporting the cut strands so that the cut and flattened strands are transformed into strands practically in the form of bars. .

  
According to another preferred embodiment of the invention, cut, flattened and impregnated strands are transported in the form of a layer or a bed while undergoing the vibrations of a plate which supports them while, in an area predetermined located in the center of the transport path, hot air is applied to the underside of the fluid bed of cut strands, so that these cut strands are compressed, after which they are dried during transport. Since hot air is applied to the underside of the vibrated and transported cut strand bed, hot air can flow efficiently through this cut strand bed to ensure very dry fast and very efficient of these strands.

   Furthermore, this hot air eliminates and evacuates lint or fibers separated from the bed of cut strands so that, as an end product, cut strands are obtained in which the fluff and the separation of the fibers are reduced to a minimum, thus giving product of a superior unit.

  
According to another preferred embodiment of the invention, cooling air is applied to the underside of the moving bed of cut strands which undergo vibrations and are transported, this downstream of the zone of application of hot air, thus ensuring rapid cooling of the cut strands.

  
In the accompanying drawings:
FIG. 1 is a schematic sectional view of an embodiment of the invention: <EMI ID = 1.1> before line II-II of figure 1; Figure 3 is a side elevational view, partially in section, of a drying apparatus incorporated in the embodiment illustrated in Figure 1, this apparatus being shown with gas supply and discharge systems; Figure 4-is an exaggerated perspective view of a piece of a flattened cut strand; Figure 5 is an exaggerated perspective view of a piece of cut strand which is obtained by exerting a rolling effect on the cut and flattened strand illustrated in Figure 4; Figure 6 is a schematic sectional view of another embodiment of the invention;

    Figure 7 is a side elevational view in section of a spheroidization and drying apparatus incorporated in the embodiment illustrated in Figure 6; Figure 8 is a side elevational view <EMI ID = 2.1>

  
supply and exhaust air adapted thereto; and FIG. 9 is a side elevational view in section of a modified embodiment of the spheroidization and drying apparatus illustrated in FIG. 7.

  
Preferred embodiments of the invention will be described below with reference to the accompanying drawings.

  
FIGS. 1 to 3 illustrate an apparatus for manufacturing cut strands of the direct cut type in which the present invention is implemented. In these figures, the reference numeral 10 designates a spinning machine below which are arranged a cutting device 20, a rolling device 40, a drying device 60, as well as a sorting and packaging device.

  
The spinning machine 10 has ovens

  
  <EMI ID = 3.1>

  
respective tapes 12a, 12b, 12c apply an ordinary finishing material containing a coating agent and a lubricant the collecting rollers 13a, 13b,
13c making these groups of filaments converge into

  
  <EMI ID = 4.1>

  
introduced into the cutting device.

  
This cutting device 20 comprises a guide roller 21, a feeding roller 22 and a cutting roller 23 facing the feeding roller 22. The entire cutting device is installed in a housing 24 open on its front face and fixed to the frame of a box spring 27 comprising a hinged cover on the front face. The guide roller 21 is arranged below the feed roller 22 in a position in which

  
  <EMI ID = 5.1>

  
from the spinning machine 10 to the feed roller 22. The roller 21 has grooves 25a, 25b,
25c which are intended to delimit the travel paths of the respective strands and this roller can be moved back and forth in its axial direction in order to vary the travel positions

  
  <EMI ID = 6.1>

  
The feed roller 22 has a surface made of an elastic material having a high friction coefficient with respect to glass fibers, for example rubber or a synthetic resin, the cutting roller facing the roller. feed 2 has a plurality of blades 26 which protrude radially therefrom and which are designed to penetrate the elastic surface of the feed roller 22 afi

  
  <EMI ID = 7.1>

  
designed to be driven directly and positively by a shaft 33 extending through a housing 32 mounted on the base 27 while the shaft 33 itself is driven by a motor 28 mounted on the top:
27 with the intervention of pulleys 29, 30 and a run <

  
  <EMI ID = 8.1>

  
the cutting roller 23 is constantly pressed against the feed roller 22 which is rotatably held by a shaft extending through the housing fixed on the bed base 27, so that the feed roller 22 is driven by the cutting roller 23 by means of friction contact and following the penetration of the blades 26.

  
  <EMI ID = 9.1>

  
which are spun and formed by the spinning machine 10

  
and which are always impregnated, are wound on the feed roller 22 beyond the corresponding grooves 25a, 25b, 25c formed in the guide roller 21 while, at the point of contact between the feed roller 22 and the roller 23, the blades provided on the latter cut them into pieces of a length determined by the spacing of the blades 26 These strand pieces, that is to say the cut strands 34, then fall into the rolling 40. During this step, the spinning force results from the adhesion of the impregnated strands wound on the surface of the feed roller 22. It is precisely this spinning force which stretches and spins the molten glass at the exit from the respective ovens

  
  <EMI ID = 10.1>

  
Rons wound on the surface of the feed roller are inevitably flattened. Since these flattened strands are then cut into strands 34, the latter have, of course, a flattened shape. The cut, flattened strands, always impregnated and falling into the rolling device 40 are subjected to the rolling effect exerted by the latter.

  
The rolling device 40 is disposed below the cutting device 20 at a location allowing it to receive the cut strands 34 falling from this cutting device 20 and it is supported by uprights 42 by means of vi absorbers. -

  
  <EMI ID = 11.1>

  
disation 44 disposed at an appropriate intermediate location of the vibration box 43, across the latter, this spheroidization plate 44 being designed to receive the cut strands 34 which fall, and to impart vibrations thereto, as well as a vibration generating device 45 fixed to the side wall of the vibration box 43 and designed to vibrate the whole of the latter. The vibration generating device 45, which is supported by the bottom of the vibration box 43 as indicated above, can be of a known type, for example, an electromagnetic generating device

  
vibration comprising an electromagnet animating springs of a reciprocating translational movement, or a mechanical device generating vibrations producing vibrations thereby rotation of an unbalance or the like.

  
At its upper end, the vibration box 43 is open to receive the cut strands:
34 coming from the cutting device 20 and, at a location on its side wall, it has an opening,
46 whose base is flush with the spheroid plate,

  
  <EMI ID = 12.1>

  
to vibrations, are transferred, via opening 46, to a drying station, either directly or indirectly by means of an appropriate transfer device. In this rolling apparatus 40, the spheroidization plate 44 can be arranged horizontally or it can be inclined slightly up or down in the direction of the opening 46. A sufficiently powerful rolling effect can be exerted on the cut strands , to then discharge the strands cut and treated by the opening 46, even if the spheroidization plate is inclined, provided that adequate vibrations are exerted on the spheroidization plate. The disa-tien.44 sphero plate itself can constitute the base plate of the vibration box 43.

  
The cut strands 34 formed by the device

  
  <EMI ID = 13.1>

  
sation 44. It is essential that the cut strands 34 subjected to the rolling effect are impregnated. It is not possible to generally determine the degree of impregnation, since this varies according to factors such as the type of rolling element, the intensity of the rolling effect, the unit of the strands. cut, etc. ; preferably, however, the content of

  
  <EMI ID = 14.1>

  
still, between about 10 and 15% by weight. It is not always essential that each cut strand be

  
  <EMI ID = 15.1>

  
impregnated only on the surface.

  
In the case of the direct cut type system adopted in the illustrated embodiment, the cut strand usually contains 10 to 15% by weight of water and is impregnated to the core, so that the cut strands can be suitably subjected to the rolling effect. If the impregnation is too weak, the cut strands can be impregnated, for example, by spraying water on them. In FIG. 1, the reference numeral 47 designates a device intended to spray water on the cut strands. On the other hand, if the water content of the cut strands is excessively high, it is possible, for example, to adopt a provision consisting in introducing hot air

  
  <EMI ID = 16.1>

  
rolling while evaporating part of the water,

  
During the rolling treatment described above, the intensity of the rolling effect cannot be determined either definitively or in general, in part because it varies (even in the vibration system illustrated only). according to factors such as the size of the strands cut, their quantity and their nature, for example, the water content and the degree of unit, and partly also

  
the fact that the rolling treatment itself can be carried out in various ways as will be explained below. However, the optimum conditions can easily be obtained in each rolling system if the condition of the product is observed during processing. In the case of the illustrated embodiment, the optimal conditions are those described below. In this case, three strands each consisting of 2,000 glass filaments having a diameter

  
  <EMI ID = 17.1>

  
directly to a length of 1.5 mm by the cooperation between a feed roller rotating at a peripheral speed of 1,000 m / minute and a cutting roller pressed against this feed roller. The cut strands thus formed are collected by a spheroidization plate with a width of 0.4 m and they are caused to travel along this plate over a distance of 1.2 m, while the plate undergoes vibrations at a frequency of 3000 Hz and at an amplitude of 4 mm.

  
when, while they are impregnated, the cut strands are treated by the rolling effect resulting from vibrations, a certain type of spheroidization effect is exerted on each piece of cut strands, so that each piece is rounded and gradually compresses and thus goes from the flattened configuration illustrated in FIG. 4 to a configuration practically in the form of a bar as shown in FIG. is important. The cut and compressed strands thus obtained are then dried. The shape of the bar and the high density are maintained until the end. One of the characteristics of this cut strand lies in the extremely low separation rate of the filaments or strands.

   This remarkable effect can be attributed to the fact that, although regular cut strands do not adhere to each other, separate filaments or strands tend to stick to each other or to regular cut strands to be brought together and compressed.

  
According to the invention, one can use a

  
  <EMI ID = 18.1>

  
other than that of the vibration type described above, for example, rotary container, fluidized bed, mixer machines, etc. An apparatus of the rotary drum, rotary disc and wave vibration type can also be used. Therefore, in this specification, the term "rolling" is used to generally refer to a effect causing the spheroidization of a material by vibration, rotation or flow, as is the case in the field of the technique of spheroidization.

  
Although it is preferable to load the cut strands by the cutting device directly into the rolling device as in the illustrated embodiment, the cut strands can be temporarily collected by a hopper, an inclined conduit or a conveyor, to then be loaded into the rolling device. This indirect loading of the material is particularly effi-cient when the rolling device is of the rotary drum type.

  
Although the embodiment described is applied to a system of the direct cut type, the invention can also be applied to other systems for manufacturing cut strands. For example, the unsweetened cake, which is wound on a reel, is cut directly or after a treatment of coating or impregnation with water with or without a finishing agent. It is also possible to subject a so-called dried cake which has been wound on a reel, then dried, to a secondary impregnation / coating treatment or to a simple impregnation treatment before cutting. It is also possible to directly cut the wick or the strand wound directly and impregnated or it is also possible to subject the wick or the strand wound directly and dried to cutting after impregnation.

   Given the principle of the invention, it is understood that the latter can even be applied to cut and dried strands which have not been subjected to rolling, that is to say to the cut strands which have been produced by the classic process. For this purpose, the cut strands obtained by a conventional process are loaded into the rolling apparatus after having been suitably impregnated with water or the cut and dry strands are loaded into the rolling apparatus * under a spray of water. .

  
Preferably, in its part located between the cutting device 20 and the rolling device
40, the cutting and rolling device which is cor &#65533; s titled this cutting device 20 and the rolling device 40 located immediately below the cutting device, in particular, the cutting and rolling device in the disconnection type system. live page, has an element to collect and dispose of unacceptable low quality cut strands.

  
In the illustrated embodiment, a device 50 is provided for collecting and eliminating these strands, this device being produced in an embarrassed manner *. stripe in the shape of a box, while it is supported and

  
  <EMI ID = 19.1>

  
picking up and removing unacceptable cut strands comprises a collector plate 51 which can rotate between an upright position and a practically horizontal position in which it can interrupt the downward flow of the cut strands in order to collect the latter, a handle 52 for rotate it, as well as an evacuation passage

  
53. The system is designed in such a way that, after having collected the cut strands;, the collector plate 51 preferably rotates from the horizontal position to a practically vertical position or to the initial position in which it is drawn up. -from the vertical position so that the cut and collected strands are discharged through the evacuation passage 53. This device
50 of the box type collecting and eliminating unacceptable strands can form a single unit with the peripheral wall 24 of the cutting device 20.

   In this case, the evacuation passage 53 is connected to an opening made in this peripheral wall 24. In the illustrated embodiment, the device
50 is assembled, at its lower end, to the vibration box 43 of the rolling device 40 via a peripheral wall 54 made of a flexible material such as canvas. It is essential that the upper and lower ends of the device 50 are at least partially open so that the cut strands can pass perfectly through. The collector plate 51 is designed to rotate in the position in which it closes the opening of the upper end of the device

  
50 when there are unacceptable cut strands which are thus collected.

  
Unacceptable cut strands are formed when the spinning and cutting operation starts or restarts after a failure in the strand formation operation due to broken filaments in some or all of the sleeves during the 'spinning and cutting operation. In this case, when starting or restarting the spinning and cutting operation, for example, when restarting, broken filaments are expelled from the sleeves and arranged in the form of strands, after which they are brought to the feed roller. However, it is extremely dangerous and practically impossible to feed the filaments directly to the feed roller, since the latter also rotates at a high speed, for example, around 1,000 m / minute.

   In order to avoid this danger it is necessary to bring the feed roller

  
at a low speed, for example &#65533; 100 m / minute. Since the speed of the feed roller is reduced, the strand formed in this state

  
inevitably has an unacceptable large diameter and therefore the cut strands become unacceptable

  
as a product. In this case, by means of the handle 52, the collector plate 51 is rotated to bring it into a position in which it closes the opening of the passage of the cut strands forming part of the device 50 in order to collect the cut strands. ; unacceptable. In the meantime, the cover of the housing 24 is pivoted to open the front face of the latter, while the expelled and new-drawn filaments are wound around the feed roller.

  
  <EMI ID = 20.1>

  
the cutting operation begins. Then, the speed of the cutting device is gradually increased and, when the speed of spinning and cutting has reached normal value to allow the production of normal and acceptable cut strands,

  
the housing 24 is closed and the collector plate 51 is rotated so that the unacceptable cut strands collected by this plate are discharged through the evacuation passage 53 towards the outside of the device, thus restoring the state normal operation. The apparatus 50 collecting and removing unacceptable strands can be manually operated as described or, alternatively, it can be driven by a motor. In the latter case, the collector plate 51 can be actuated automatically when a failure occurs during the spinning operation.

  
The strands cut and thus treated under a rolling effect are then dried to form the final product. The drying can be carried out by a usual means; for example, stationary drying can be used in which hot air or high frequency wave heating is used. However, the cut strands produced by the process of the invention can be most effectively dried.

  
  <EMI ID = 21.1>

  
cut which flows under vibrations and this, via a number of small openings opening onto the underside of the flowing bed, so that the hot air passes through the thickness of the latter.

  
The illustrated embodiment comprises a drying device 60 comprising an envelope or main body 61, a support plate or a perforated plate 62 which receives the flowing bed and which extends across the envelope, a generator device vibration 63 attached to one of the side walls of the casing 61 and designed to impart vibrations to the latter, as well as an air supply system and an air exhaust system.

  
The interior space of the envelope 61 is divided, by the perforated plate 62, into a lower section constituting a hot air supply chamber 64 and an upper section constituting an air discharge chamber 65. envelope 61 is supported by the lower wall of its air supply chamber 64 by means of support pillars 67 and via vibration absorbers 66. A duct 81 leaving from the air supply system is connected to the opening 68 practiced in a side wall of

  
the air supply chamber 64 so that the hot air is introduced into the latter via this opening 68. The hot air thus distributed is discharged through small perforations made in

  
the support plate 62, then it flows through the bed of cut strands 34 which are deposited on the plate
62 and which are thus heated and dried. The cut and dried strands are then continuously discharged through the outlet. The cut strands can then be sorted and cooled naturally to constitute the final product. However, natural cooling is not exclusive and the strands cut

  
  <EMI ID = 22.1>

  
may be subjected to forced cooling. To this end, in the illustrated embodiment, the outlet end of the air supply chamber 64 is divided by a partition 69 in order to form a cooling air chamber 70. A duct 88 starting from a cooling fan
87 is connected to an opening 71 formed in a side wall of the cooling air chamber 70. The cooling air supplied by the opening 71 is discharged through the perforations made in the plate 62. The evacuation chamber d 'air 65 includes,

  
  <EMI ID = 23.1>

  
a small cross section at the lower end of the front wall of the casing 61, as well as a discharge opening 73 provided at the top thereof and connected to a discharge duct 84, in this embodiment , the drying device
60 forms a single unit with the rolling apparatus by assembling its side walls to the casing 61 by means of peripheral walls 74 and 75 which are flexible and which allow the casing 61 and

  
the vibration box 43, to vibrate independently of one another,

  
The support plate 62 which is held transversely in the envelope 61, comprises several small perforations with a diameter lying between 1 and 5 mm, preferably between 2 and 3 mm,

  
  <EMI ID = 24.1>

  
3% to allow the passage of hot and cold air from the air supply chambers
64 and 70 respectively. This plate 62 is located

  
at a level slightly below the opening 46

  
of the rolling device 40, its end closest to the opening 46 being curved upwards moreover, this plate is held inside the envelope 61 in a practically horizontal position or with a slight inclination in direction

  
from the outlet 72 provided for the cut strands. On the other hand, the spheroidization plate 44 of the rolling apparatus 40 extends through the opening 46 to enter the drying device 60 by overlapping the plate 62 over a predetermined area so that the strands cut , impregnated and treated by the rolling apparatus 40 are caused to fall on the plate 62 undergoing vibrations. Although in

  
  <EMI ID = 25.1>

  
disation 44 has one end curved down and extending into the dryer, this is not an exclusive feature and this end of the

  
  <EMI ID = 26.1>

  
lement. The vibration generating device 63 can be the same device as that described above in connection with the rolling apparatus.

  
The air supply and exhaust systems of the drying device 60 are hot air supply and exhaust systems, as well as a cold air supply system. The hot air supply and exhaust systems include a hot air loading system consisting of an air distribution blower 80, a duct 81 extending from this blower 80 and connected to the opening
68 of the air supply chamber 64, as well as of a heating device 82 located at a point indi-

  
  <EMI ID = 27.1>

  
cuation consisting of a conduit 84 connecting the discharge opening 73 of the chamber 65 and the discharge blower 83, a recycling conduit going from the outlet of the discharge blower 83 to the supply blower air 80, as well as a conventional device for collecting dust 86, for example a cyclone disposed at an intermediate point of the conclusion:

  
  <EMI ID = 28.1>

  
tion of cold air comprises the cooling blower 87 and a duct going from this blower 87

  
  <EMI ID = 29.1>

  
cooling air 70. The cold air exhaust system is common to the hot air exhaust system. Although it has not been shown, the connections between the conduits 81, 84, 88 and the openings

  
  <EMI ID = 30.1>

  
canvas which are fixed by flanges at their ends so that they absorb the vibrations of the drying device 60.

  
The air discharged from the supply blower 80 is heated by the device 82, then it is introduced into the air supply chamber

  
  <EMI ID = 31.1>

  
in the evacuation chamber 65 via the perforations made in the plate 62 as indicated by arrows, while heating the latter. Hot air entering the hot air supply chamber

  
64 is usually at a temperature between

  
  <EMI ID = 32.1>

  
flow rate of this air is adjusted to generally establish a flow speed of 3 to 12 m / second, preferably 5 to 8 m / second through each perforation, although this flow rate can be varied according to different factors such as the feed rate of the cut strands in the drying device, the water content of the cut strands, the dimensions of the plate 62, the dimensions and the porosity of the openings, etc. On the other hand, the cold air introduced into the cold air supply chamber 70 can be air at room temperature and the flow rate of this air is generally adjusted to establish a flow rate of 4 to 6 m / second for each perforation.

  
The cut and impregnated strands which are loaded via the opening 46 in the rolling device
40, fall on the support plate 62 which undergoes vibrations, for example, at a frequency of 1.450 Hz and at an amplitude of 2 mm, after which they are moved towards the outlet 72 in the form of a laminar bed in which the strands cut are agitated and mixed under the action of hot air projected by the perforations in the plate. The cut strands constituting the moving bed are dried by the hot air flowing through this bed. At the same time, the flow of hot air has the effect of blowing and evacuating the fine filaments and strands separated from the cut strands, these separated filaments and strands being sucked in and evacuated through the conduit 84 together with the hot air. .

   An experiment has revealed that the quantity of filaments and strands eliminated by the apparatus 86

  
  <EMI ID = 33.1>

  
the total quantity of cut strands introduced into the drying device 60 and that, under these conditions, the dried product formed by the cut and compressed strands of the invention did not contain fine separate filaments and strands which could alter the operating characteristics and formability.

  
The cut and dried strands are at a temperature

  
  <EMI ID = 34.1>

  
they can be subjected to natural cooling. However, it is preferable to subject the cut strands to forced cooling. In the illustrated embodiment, the forced cooling of the cut strands is carried out by the cooling blower 87 which, via the conduit 88, sends cold air or air at room temperature into the supply chamber d cold air 70 which is formed by dividing the front end of the hot air supply chamber 64 and projecting this air through the perforations in the support plate 62, thereby positively dissipating the heat to cool the cut strands .

   The hot air and the cold air distributed respectively by the hot air supply chamber 64 and the cold air supply chamber 70, to then be discharged into the room
65 beyond the perforations in the plate
62 while drying and heating the cut strands, are formed by the blower 83 via the evacuation duct 84 so that the separated filaments and strands are eliminated by the dust collecting device 86 provided at an intermediate point of the duct 84 Then, the air freed from the separated filaments and strands is recycled, via the conduit 85, to the blower 80, then it is recycled to the drying device as drying air.

  
The cut strands thus dried, then cooled, are caused to fall from the outlet 72 of the drying device 60 in a sorting device 90 and thus, the residual filaments and free strands which possibly remain, as well as the poorly cut strands and d other foreign matter is removed from the cut strands. The cut strands then pass through a device 91 eliminating the metal and they are conditioned into final product 92, while the waste and foreign matter separated and eliminated by

  
  <EMI ID = 35.1>

  
discharge structure 93.

  
In the conventional immobile type drying system for cut strands, it takes a long time (for example, 15 hours) to dry the cut strands. Likewise, it is feared that migration of the finishing agent will take place during drying. However, according to the inventa drying system which has been described above, it is possible to achieve uniform drying in a short period of 15 to 30 minutes without fear of possible migration of the agent. finishing and while getting rid of separated filaments and strands. Therefore, as a final product, high quality cut strands can be obtained.

  
A preferred embodiment of the invention has been described mainly with reference to a manufacturing system of the direct cut type. According to the method and the apparatus of the invention, it is possible to form cut strands which are suitably dried, in particular, by the device.

  
described dynamic drying ensuring high drying efficiency as previously stipulated. Furthermore, as a final product, the cut strands have a markedly reduced content of separate filaments and strands, they have a markedly reduced lint and they have a high density, as well as a practically rounded configuration in the form of a bar instead of 'a flattened shape, thus perfectly meeting the current requirements imposed for rationalization and systematization, as well as with regard to formability.

  
The results of the manufacture of cut strands according to the invention will be described in the example.

  
  <EMI ID = 36.1>

  
  <EMI ID = 37.1>

  
Three strands are spun from three sleeves, each with cooling fins and 2,000 nozzles at their ends, then an ordinary finishing agent containing a coating agent and a lubricant is applied. Via a guide roller, these three strands are introduced into the cutting device which consists of a cutting roller on the periphery of which radial blades are provided at a circumferential spacing of 1.5 mm as well as a roller d feed against which this cutting roller is pressed. Cutting is carried out by rotating the feed roller

  
at a peripheral speed of 1,000 m / minute. The cut strands thus formed have a flat configuration and a water content of about 12%.

  
The cut and impregnated strands thus obtained are dropped directly into a vibration boot which is arranged immediately below the cutting device and they are treated by the vibrations caused by the spheroidization plate which is arranged transversely in this vibration box. The width and length of the spheroid plate -

  
  <EMI ID = 38.1>

  
and the amplitude of the vibrations is 3,000 Hz and

  
4 mm respectively. Following the treatment imposed by the vibrations, the cut strands gradually lose their flat configuration to take a rounded configuration in the form of a bar. The cut strands, impregnated and thus treated with vibrations are then introduced into the drying device comprising a perforated plate receiving the bed of cut strands, arranged in the transverse direction of this device and defining, on its upper face and its lower face respectively. , an air supply chamber and an air exhaust chamber in the presence of vibrations with a frequency of 1.450 Hz and an amplitude of 2 mm.

   Hot air brought to a temperature of 150 [deg.] C and introduced into the air supply chamber is projected upward through each perforation of the aforementioned plate at a speed of 7 ni / second in order to dry the cut strands as they move towards the exit of the drying device. This perforated plate has a width of 0.45 m and a length of 3.2 m, while it has small perforations with a diameter of 2 mm with a porosity of 3%. The residence time of the cut strands in the drying device is approximately 30 minutes. Then the cut and dried strands are abandoned and allowed to cool naturally to result in the final product.

  
Table 1 indicates the quality of the cut strands thus obtained compared to cut strands produced by a conventional process. The conventional method adopted for this comparison consisted in directly drying the cut strands under conditions of immobility by means of hot air brought to a temperature of 130 [deg.] C without subjecting them to the treatment.

  
.

  
of rolling.

  
In Table 1, the specific gravity is measured by uniformly depositing 200 g of cut strands in a graduated measuring cylinder of 1,000 ml, the volume being read in g / cm3. According to this experience,

  
a higher specific gravity can be considered as the index of a weaker lint and a higher density in the cut strands.

  
The fluidity value is determined as described below. 500 g of cut strands are placed in a pyramid-shaped hopper having an inlet opening forming a square 20 cm in side, an outlet

  
  <EMI ID = 39.1>

  
15 cm, the outlet of this hopper being opened by undergoing vibrations at a frequency of 3,000 Hz

  
  <EMI ID = 40.1>

  
the time required to evacuate all the cut strands is measured and determined. A lower fluidity value is the index of a reduced fluff and a higher density in the product.

  
We measure the lint formation rate of

  
  <EMI ID = 41.1>

  
ml, 60 g of pellets of a resin of a diameter are deposited <EMI ID = 42.1>

  
40 g of cut strands, then seal the beaker and stir for 3,000 cycles to mix the resin pellets and the cut strands. Next, the degree of separation or fibrillation of the cut strands is measured by sieving the mixture using a 16-mesh sieve and determining the ratio (%) between the amount of fibrillated fibers remaining on the sieve and the total amount of cut strands initially deposited on the latter. This ratio is used as the fluff formation rate. This ratio is used as an index of resistance of the cut strands to external mechanical forces. In this case, the lower this ratio, the higher the convergence and the unity of the cut strands.

  
The rate of residual strands is measured as described below. By dropping the cut strands out of the hopper, hot air is blown in from the sides in order to separate and blow out the fine filaments and strands. the ratio (%) between the filaments and strands thus separated and the initial weight of the strands, this ratio being used as the percentage of residual strands. In this case, the lower the value of this ratio, the more the fibrillation is reduced. Table 1

  
Characteristics of the strands

  
cut

  

  <EMI ID = 43.1>


  
From the comparison established in table 1 above, it can be seen that the cut strands produced in accordance with the present invention exhibit a significantly reduced lint and fibrillation while they have greater convergence and unity, as well as high density and high resistance to external mechanical forces thanks to the rolling treatment according to the invention.

  
In the first embodiment described above, the rolling treatment and the drying of the cut strands are carried out in separate steps, but these two steps can be carried out in a single device.

  
FIGS. 6 to 8 illustrate an apparatus for manufacturing cut strands comprising an apparatus for

  
  <EMI ID = 44.1>

  
temporarily the rolling effect and the drying of the cut strands.

  
Referring to these figures, the reference numeral 110 designates a spinning machine comprising:

  
  <EMI ID = 45.1>

  
spun a multitude of filaments 112a, 112b and 112c to which a binder is applied by means of primer applicators 113a, 113b and 113c. By means of skates col-

  
  <EMI ID = 46.1>

  
115b, 115c which are then introduced into a cutting device 120.

  
This cutting device 120 comprises a guide roller 121 in which grooves are made in a number corresponding to that of the strands., A feed roller 122 which can rotate freely and having a surface made of an elastic material having a large coefficient of friction with glass fibers, for example rubber or a synthetic resin, as well as a cutting roller 123 pressed elastically against the supply roller 122 and positively driven by a motor., several blades protruding radially of the periphery of this cutting roller 123.

   The impregnated strands 115a, 115b and 115c introduced into the cutting device 120 are wound around the feed roller 122 beyond the grooves of the guide roller 121 and * at the point of contact between the feed roller 122 and the roller cutting 123, they are cut into pieces, that is to say into cut strands 130 of a length which is determined by the circumferential spacing of the blades, following the penetration of the latter into the elastic surface of the roller d 'food. The impregnation of the cut strands 130 thus formed varies according to the rate of application of binder during spinning but, as a general rule, the water content is between approximately 10 and 15% by weight.

  
During the spinning step and the direct cutting step which have been described above, the

  
  <EMI ID = 47.1> <EMI ID = 48.1>

  
tation 122 on which the impregnated strands are tightly wound. Under the effect of this spinning force., The groups of glass filaments 112a, 112b

  
  <EMI ID = 49.1>

  
are transformed into fibers.

  
By adopting the direct cutting system which has been described above, the cut strands 130 can be obtained immediately after spinning. Although the invention is preferably applied to the spheroidization and to the drying of cut strands obtained by the direct cutting type method described above, the invention can also be applied to the sphere ...

  
  <EMI ID = 50.1>

  
methods other than that described above%, For example, the invention can be applied to the treatment of cut strands obtained by the formation of an undried cake by winding the spun and gathered strands, then routing this undried cake to a cutting device where it is cut directly or indirectly after having undergone a coating or impregnation treatment by means of an aqueous treatment agent with or without a finishing agent, The invention can also be applied to the treatment of cut strands which are obtained by forming a so-called dried cake by winding the strands on a reel and

  
  <EMI ID = 51.1>

  
where it is cut after having undergone a secondary coating and impregnation treatment or a simple impregnation treatment. Although the above description is mainly concentrated on strands, those skilled in the art will understand that the invention can also be applied to the sphero [pound] disation and the drying of cut strands obtained by cutting the impregnated products obtained from strands. , for example- <EMI ID = 52.1>

  
directly and formed directly during spinning while omitting the wicking step. In this specification, these products obtained from strands will hereinafter be referred to as "secondary strand products 11. The water content of cut strands or secondary strand products varies with the types thereof, but is usually in the range of between about 10 and
25% by weight.

  
The cut strands 130 formed by the cutting device 1.20 'are brought to fall on suitable conveying elements such as the systems

  
  <EMI ID = 53.1>

  
transported to the spheroidization and drying device 150. The supply of the cut strands to the spheroidization and drying device 150 is usually carried out continuously, although it can also be carried out intermittently,

  
The cut strands thus loaded into this device are dried and, preferably, cooled, then they are discharged as final product and they are conditioned by a device 190.

  
The spherotizing and drying apparatus
150 comprises an envelope inside of which is horizontally disposed a single support plate or spheroidization plate 151 receiving the bed of cut strands. The interior space of the aforementioned envelope is divided by this spheroidization plate
151 into an air exhaust chamber 152 defined on the upper face of the plate 150 and of the chambers

  
  <EMI ID = 54.1>

  
bottom of the plate 150. A vibration generating device 154 intended to vibrate the entire drying and spheroidizing device is fixed to one of the side walls of the envelope. In addition, as auxiliary systems, the spherrordization and drying device comprises air supply and exhaust systems connected to the air supply chambers 153a, 153b and to the exhaust air chamber. air 152.

  
In this spheroidization and drying apparatus 150, the spheroidization plate 151 comprises a non-perforated zone A constituting the zone where the cut, impregnated and thus charged strands undergo spheroldization by vibrations, as well as perforated zones B and C located in the extension of the non-perforated zone and constituting the drying and cooling zone - cut strands which flow in the form of a bed from the non-perforated zone A. The perforated zones B and C comprise a multitude of 155 holes drilled right through, having

  
  <EMI ID = 55.1>

  
spheroidization 151 is arranged inside the envelope either horizontally or with a slight inclination towards the exit.

  
The air evacuation chamber 152 has, in its wall, an inlet opening 156 for loading the cut and impregnated strands into the end of the non-perforated area, as well as an outlet opening 157 for the cut strands., this opening 157 being formed in the end of this chamber which is opposite to that where the opening 156 is located, at a level allowing the cut strands which flow on the spheroidization plate 151, to be evacuated through this opening. In addition, the air evacuation chamber has an opening 158 for evacuating the air loaded in this chamber. The air evacuation opening 158 is connected to an external air evacuation system. .

  
It is preferable that the air supply chamber is divided, by a partition 159., into a hot air chamber 153a adjacent to the rear end wall, that is to say the end wall in which is made the inlet opening 156 for the cut strands, as well as in a cold air chamber 153b adjacent to the front end wall, that is to say the end wall comprising the outlet opening 157 for the cut strands, as shown in the illustrated embodiment. However, the cold air chamber
153b can be omitted provided that the cut strands heated to a high temperature by the hot air applied through the holes in the spherotization plate 151 can be cooled naturally.

   Each of the air supply chambers 153a and 153b can be further divided into several sections, although individual chambers are sufficient in most cases. However, in the illustrated embodiment, the two air supply chambers 153a and 153b are separated from each other by the partition plate 159. However, the use of this partition plate is not not essential and these chambers are formed separately from each other from the start. Openings

  
  <EMI ID = 56.1>

  
these openings communicating with a hot air supply system and a cold air supply system. When each air supply chamber

  
at a large volume or when divided into sections, several openings 160a can be formed or

  
  <EMI ID = 57.1> starting from a corresponding air supply system are connected to these openings.

  
The vibration generating device 154 is fixed to one of the side walls of the drying device, preferably in the lower part of the side wall, for example, the part of the side wall defining the air supply chamber, and it is designed to impart vibrations to the entire apparatus 150. The vibration generating device 154 may be of a known type, for example, an electromagnetic vibration generating device comprising an electromagnet designed to drive springs parallel back and forth movements, as well as a mechanical vibration generating device designed to produce vibrations following a rotary movement of an unbalance.

  
The air supply and exhaust systems include a supply system and a exhaust system for hot air, as well as a supply system for cold air. More specifically, the hot air supply system comprises a blower 161 ensuring the air supply, a duct 163 connecting the blower 161 to the opening

  
  <EMI ID = 58.1>

  
ducts in canvas 162 absorbing vibrations, a damper (not shown) being provided for regulating the flow rate, while a heating device 164 is installed at an intermediate point of the duct 163 and is designed to heat the air sent by the blower
161 at a desired high temperature. The hot air exhaust system comprises an air exhaust blower 165, a duct 167 connecting the air exhaust opening 158 of the air exhaust chamber 152 and the air blower exhaust air 165 via ducts 166, a damper (not shown) being provided to regulate the flow, as well as an exhaust air 168 leaving from the exhaust air blower 165 .

   Preferably, the air supply system and the exhaust air system are connected to each other by a recycling duct.
169 so that the hot air brought by its supply system into the air supply chamber 152 is sent and recycled, by the blower

  
  <EMI ID = 59.1>

  
hot air via the recycling duct 169. This recycling system can be implemented, for example, by connecting the air exhaust duct 168 to a dust collecting device 170 such as a cyclone, the recycling duct 169 starting from the dust collecting device 170 to reach the suction side of the air supply blower 161. In the preferred embodiment comprising the air supply chamber 153b for cooling air, the air supply system connected to this chamber 153b includes a supply blower

  
  <EMI ID = 60.1>

  
air ment 153b via canvas ducts (not shown), a register (not shown) being provided for regulating the flow rate. There is no need for an independent exhaust system for the cooling air. In this case, as in the case of the illustrated embodiment, in the systems intended for hot air and for cold air, the exhaust chamber 152. is commonly used. This evacuation chamber 152 provided for hot air is used not only as an exhaust chamber for hot air, but also as an exhaust chamber for cold air.

  
The spheroidization and drying apparatus
150 is resiliently supported on the lower walls of its air supply chambers 153a,

  
153b by the intervention of vibration absorbers such as springs 173 by means of support pillars 174 placed vertically on the ground so that the whole of the apparatus is animated by vibrations by the vibration generating device 154.

  
The masses of cut strands 130 which the conveyor systems 140a, 140b and 140c convey continuously or intermittently in the spheroidization and drying apparatus 150, are caused to fall on the non-perforated zone A of the sphere plate.

  
  <EMI ID = 61.1>

  
the action of the vibration generating device 154, the cut strands then being moved towards the perforated zone B in the form of a laminar bed while undergoing jolts under the effect of vibrations. In the perforated zone B, the cut strands 130 form a practically fluidized bed 175 under the action of vibrations., As well as under the effect of the hot air projected by the multitude of perforations, so that these cut strands are moved naturally and in

  
  <EMI ID = 62.1>

  
The cut strands 130 loaded on the spheroidization plate 151 undergo a rolling effect resulting from the vibrations, while they pass through the non-perforated zone A. It is essential that the cut strands are subjected to this rolling effect while they are still permeated. The degree of impregnation cannot be determined definitively, since both the preferred degree of impregnation varies according to various factors such as the degree of unity of the cut strands. However, the water content of the cut strands is generally between <EMI ID = 63.1>

  
pés can in particular be impregnated only on the surface. In the direct cut type system of the illustrated embodiment, the strands are usually impregnated to the core and have a

  
  <EMI ID = 64.1>

  
by weight, so that the cut strands can be advantageously subjected to the rolling effect resulting from the vibrations. However, if the water content is too low, water is added to the cut strands, for example by spraying.

  
When the cut and impregnated strands are subjected to the rolling effect resulting from vibrations,

  
  <EMI ID = 65.1>

  
by being prevented from joining or being linked to each other. Consequently, the cut strands gradually change from the flattened shape illustrated in FIG. 4 to a practically bar-shaped configuration as shown in FIG. 5. The cut and impregnated strands which have been subjected to spheroidization and which have been compressed, are then dried, but each cut strand retains its configuration in the form of a bar until the end, ultimately becoming a compressed cut strand in which the fluff is reduced and whose specific gravity is high. The length of the non-perforated zone A of the spheroidization plate 151 constituting the rolling spheroidization zone varies according to the high density or the high compactness to be produced but, as a general rule, it is between 1 and 2 m.

  
The cut and impregnated strands that have been

  
  <EMI ID = 66.1> in the non-perforated zone A by forming a fluid bed, move towards the perforated zone B where they form

  
a practically fluidized bed 175 under the action of hot air applied by the holes 155 and under the effect of vibrations, so that these cut strands are dried and moved naturally towards the outlet 157. In order to

  
  <EMI ID = 67.1>

  
cut strands, as well as for deposit. of the fluid bed and the regular transport of the cut strands, the spheroidization plate 151 is animated by vibrations at a frequency generally between approximately 500 and 3,000 Hz, preferably between

  
  <EMI ID = 68.1>

  
a few millimeters, for example, 1.5 to 3 mm. According to variable factors such as the feed rate of the cut strands, the water content of the latter, the feed rate of the drying air,

  
  <EMI ID = 69.1>

  
regular transportation. In this case, in accordance with the method described for the application of vibrations, the separation of the strands cut one apart from the other is partially favored by the fact that they undergo the effect of projection of the drying air while being animated by vibrations and, in part also due to the fact that the adhesion of the cut strands is reduced following the rapid evaporation of the water attributable to the application of the drying air. Consequently,

  
avoids the untimely formation of large agglomerated pieces during transport, while the cut toons are transported regularly by forming a laminar fluid bed.

  
The heating air intended to dry the cut and impregnated strands going from the non-perforated zone A to the perforated zone B is obtained by heating, to the desired temperature, the air distributed by the blast-

  
  <EMI ID = 70.1>

  
air ment 153a and, while heating the plate

  
spheroidization 151, it is discharged, via the small perforations 155 formed in the perforated zone B, into the air evacuation chamber 152 passing through the fluid bed of cut strands, thus promoting the formation of the fluid bed 175. The projection effect of the heated air causes rapid evaporation of a large part of the water content of the cut strands when they are introduced into the perforated zone in order to promote the separation of the cut strands into independent strands, thus contributing to the formation of the laminar fluid bed 175. The cut strands of the bed 175 are not necessarily caused to float perfectly under the action of the heated air, but they are sufficiently agitated and mixed to uniform the fluid bed, thus further promoting the drying.

   The thickness of the bed is generally between 0.5 and 3 cm, preferably between 1 and 2 cm.

  
In order to exert these effects of heated air, it is necessary to appropriately determine the temperature and flow rate of the heated air. The flow rate and the air temperature, however, depend on various factors in the perforated area B and the flow rate is more restricted since it is necessary to prevent the cut strands constituting the fluid bed from being blown strongly deviation, so that it is not possible to generally and definitively determine the air flow and temperature. However, the air temperature is preferably

  
  <EMI ID = 71.1>

  
sea: in air, a flow speed of about 3 to 12 m / second, better still, about 5 to 8 m / second for each perforation. It is also preferable that the temperature and the flow rate of the air are chosen in a mutual relation such as the air situated immediately above the fluid bed 175, i.e. the air hardly leaving this 175 bed (this air having of course a temperature lower than that which it has before entering the 175 bed) or at a temperature between about 100 and 110 [deg.] C. Under these conditions, ordinary strands cut in the wet state, as well as direct cutting strands having a water content of about 10 to 25% are perfectly dried in 15 to 30 minutes.

   When, to date, drying has been completed in such a short period of time, if some type of hardening type binder is used, it is feared that the binder cannot be sufficiently cured. However, we can

  
  <EMI ID = 72.1>

  
and projections of hot air facilitates the separation of the cut strands and the formation of a laminar bed thereof. As a result, the supply rate of hot air can be reduced compared to the system in which vibration is not used, so that the method of the described embodiment can be applied to the processing of further cut strands. short length, for example, from 1 to 3 mm.

  
As indicated above, the cut and dried strands usually have a temperature above 100 ° C. It is possible to abandon the strands heated at high temperature in order to subject them to natural cooling just as in the process. conventional but, in order to take full advantage of the high efficiency of the spheroidization and drying according to the invention, it is preferable to adopt the cooling air supply system so as to subject the cut strands to forced cooling of the same way as for drying.

  
In this case, the cooling air is routed, through the supply blower 171 and via the conduit 172, into the air supply chamber 153b and it is projected, via the small perforations 155, into the area perforated C of the plate

  
  <EMI ID = 73.1>

  
through the small perforations 155 is caused to flow through the bed 175 of cut and hot strands moving along the perforated zone B of the spheroidization plate 151, thus dissipating the heat of these strands, this air then being sent in the exhaust air chamber. The ambient air which is at room temperature can advantageously be used as cooling air. The speed of flow of the cooling air projected by the small perforations 155 in the perforated zone C can be lower than the speed of flow of the drying air and it can be between approximately 1 and

  
10 m / second, preferably between about 4 and 6 m / second. Following this dynamic cooling of the cut strands in the form of a laminar fluid bed, the cut strands brought to a higher temperature.

  
to 100 [deg.] C are cooled to room temperature in a short period of 5 to 10 minutes.

  
During the drying and cooling stages described above, the cut strands which have been subjected to spheroidization and which have been compressed, retain their unity practically perfectly even under the application of jets of heating air. and cooling air for dynamic drying and cooling. Consequently, as will be understood on reading the description of an example, the embodiment described above gives cut strands having a high specific weight and, consequently, a high density, without it poses no problem such as migration of the binder, rupture of the binder, etc., since both the agitation and the mixing of the strands cut in the laminar fluid bed shorten the heating time.

  
  <EMI ID = 74.1>

  
drying and cooling air are projected from the air supply chambers 153a and 153b via the small perforations 155 in the spherotization plate 151 and they flow into the air exhaust chamber 152 passing through the bed fluid 175 of strands cut to then merge into one another. The air is then sucked in and out

  
  <EMI ID = 75.1>

  
preferably, the evacuated air is brought to pass through a dust collector 170 where the released filaments and strands are eliminated from the air, after which this air is recycled to the supply blower 161, then distributed in the apparatus as heating air after passing through the heater 164.

  
During the drying and cooling stages described above, the fine filaments and strands released from the cut strands at the time of cutting are collected from the exhaust air under normal conditions of drying and cooling at a rate of 0.5 to 2% of the total quantity of loaded cut strands, although this rate varies according to the speeds of the heating air and the cooling air. Even if a part of these released filaments and strands remains in the cut strands, they remain tightly fixed and joined to these while the cut and impregnated strands roll in the non-perforated area.

  
  <EMI ID = 76.1>

  
in no way affect the quality of the cut strands as the final product In the conventional process in which the drying air is applied while the cut strands remain stationary., as the final product, the cut strands can only have a low specific weight. This characteristic seems to be attributable to the fact that a very large part of the fine fibers and of the fine released strands remain attached to the cut strands and that they are dried together with these, thus increasing the volume. The cut strands, which have been dried and cooled, are caused to fall from the product outlet opening 157 into an ordinary sorting apparatus 180 where. poorly cut strands and other unacceptable cut strands are separated as waste and disposed of via the discharge opening 18le to a container 182 receiving the scrap.

   The cut strands which are now cleared of the waste are conveyed, via a device 183 eliminating the metal chips, to a product container 184 while being weighed. When ' predetermined weight is reached, the cut strands are sent to a conditioning device 190 where they become the final product 191.

  
In the sorting step described above, the cut strands which have been dried and cooled do not tend to form large pieces which are partly agglomerated because the released filaments and strands are practically eliminated by the jet. air and, partly also because the migration of the binder which can give rise to the formation of large agglomerated pieces, is practically eliminated. Consequently, it is possible to obtain a continuous and regular evacuation of the cut strands practically at a constant rate.

  
In the spheroidization and drying apparatus illustrated in FIG. 7, the non-perforated area

  
A is adjacent to the strand feed opening 156. As indicated above, the length of this non-perforated area A is determined according to the degree of compression which the cut strands must achieve, as well as depending on the impregnation of the cut strands that are routed there. Unperforated area A can be omitted if strong compression is not required. Figure 9 illustrates a device

  
  <EMI ID = 77.1>

  
the fluid bed and which is free from the non-perforated zone A. Consequently, in this embodiment, the cut and impregnated strands coming from the feed opening 156 are directly subjected to the effects of rolling and drying.

  
Examples II and III below illustrate the results of tests for manufacturing strands cut using the apparatus illustrated in FIGS. 6 to 8, as well as by means of the apparatus shown in FIG. 9.

Example II

  
Using a conventional spinning process and applying two different types of binders

  
  <EMI ID = 78.1>

  
three sleeves each having 800 nozzles at their ends. The glass fibers are joined into three independent strands by collecting pads and these three strands are introduced, via a guide roller, into a cutting device which is constituted by a cutting roller of the peripheral surface from which several radial blades, as well as a feed roller against which the cutting roller is pressed, so that after their passage through this cutting device, the strands then become cut strands. The cut and impregnated strands thus obtained have a flattened structure and a water content of 12%.

   The cut and impregnated strands accumulate on the conveyor located just below the cutting device and they are conveyed to the spheroidization and drying apparatus of the type illustrated in FIGS. 7 and 8 in which the spheroidization, the drying and cooling is carried out to obtain the final product. The water content of the product is lower than normal, that is to say that it is lower than 0.03%, thus confirming that the cut strands have been practically dried perfectly. As a final product, the cut strands also have a rounded bar-shaped configuration. Feed rate ..

  
  <EMI ID = 79.1>

  
sation and drying is about 45 kg / hour, while the thickness of the fluid bed of strands cut in the perforated area of the spheroidization plate is about 10 to 15 mm with application of hot air.

  
In the spheroidization and drying apparatus used, the spheroidization plate has a

  
  <EMI ID = 80.1>

  
followed by a perforated drying zone corresponding to the hot air supply chamber located

  
  <EMI ID = 81.1>

  
having an area of 1.125 m2 (450 mm wide and
2,500 mm long). The remaining part of the plate <EMI ID = 82.1>

  
the passage of cooling air,

  
In order to ensure safety conditions, this spheroidization plate. on which the fluid bed is deposited, is designed with dimensions somewhat greater than the minimum dimension required for

  
  <EMI ID = 83.1>

  
carries small perforations with a diameter of 2 mm evenly dispersed in the perforated area with

  
  <EMI ID = 84.1>

  
and an amplitude of 2 mm and this, under the action of the mechanical device generating vibrations which it has

  
  <EMI ID = 85.1>

  
sation and drying comprises a hot air supply system and a cold air supply system connected to their respective air supply chambers, as well as an air exhaust system comprising a cyclone and connected to the air exhaust chamber of the device. As hot drying air, air brought to a temperature of 150 [deg.] C is used, which is projected at a flow speed of 5 m / second through each of the small perforations. The cooling air which is the air of the environment at room temperature is also projected at a flow speed of 5 m / second through each perforatic

  
  <EMI ID = 86.1>

  
cooling times are approximately 8 minutes, 17 minutes and 6 minutes respectively *

  
Table 2 gives the characteristics of the cut strands thus obtained compared to the characteristics of cut strands which were obtained by drying the cut strands and impregnated to the same degree in the form of a fixed bed with a thickness of 60 mm.

  
  <EMI ID = 87.1>

J

  
for 10 hours with air circulation. hot to

  
  <EMI ID = 88.1>

  
In Table 2, the water contents are the water contents of the cut strands which have been

  
  <EMI ID = 89.1>

  
dissement.

  
The deposition rate is the weight ratio between the binder and the fibers in the cut strands constituting the final product while the insolubility is the weight ratio between the remaining undissolved binder and the amount of binder existing before treatment when boil the tarons cut and dried with the binder and when they are dissolved in toluene for 1 hour.

  
The fluidity value is determined as described below. 100 g of cut strands are placed in a pyramid-shaped hopper having an inlet forming a square 20 cm in side, an outlet forming a square 2.5 cm in side and a height of 15 cm de

  
the square output being open while applying vibrations with a frequency of 3 * 000 Hz and an amplitude of 2 mm, measured at the input. Then, as fluidity value, we measure and determine, in terms

  
seconds / 100 g, the time required to evacuate all cut strands. The lower the fluidity value, the less lint is important. Likewise, a lower fluidity value is the index of a high density in the product.

  
The specific weight is determined by uniformly depositing 200 g of cut strands in a graduated measuring cylinder of 1,000 ml and reading the volume in terms of g / cm3. According to the experience acquired, a higher specific weight can be considered as an indication of less lint and a higher density in the product.

  
The rate of lint formation is measured as described below. 100 g of cut strands are placed in a 1,000 ml beaker which is stirred for 3,000 cycles to mix the cut strands.

  
The fibrillation rate following the vibrations is measured by sieving the cut strands having undergone the vibrations, by means of a 16-mesh sieve and by determining the ratio between the fibrillated strands and the total amount of cut strands fed to the sieve. This rate (%) is used as the lint formation index (CS). We measure the rate of fibrillation
(CS / R) in the same way as the rate (CS), with the exception that 40 g of cut strands are mixed with
60 g of resin pellets each having a long

  
  <EMI ID = 90.1>

  
can be considered as the resistance index to external mechanical forces. In this case, the lower the rate of lint formation, the higher the bond and unity of each piece of cut strand.

  
TABLE 2

  
Characteristics of cut strands

  

  <EMI ID = 91.1>

Example III

  
By a conventional spinning process and with the application of two different types of hard binders

  
  <EMI ID = 92.1>

  
three sleeves each having 800 nozzles at their ends. The glass fibers are gathered in three independent strands by means of collecting pads and lion introduced these three strands, via a guide roller in a cutting device which consists of a cutting roller of the peripheral surface from which several radial blades emerge. , as well as a feed roller against which the cutting roller is pressed, so that the strands are cut by this cutting device to become cut strands, The cut strands and im-

  
  <EMI ID = 93.1>

  
The cut and impregnated strands accumulate

  
on the conveyor located just below the cutting device and they are conveyed to the drying apparatus of the type represented in FIG. 9 in which the spheroidization, the drying and the cooling are carried out to obtain the final product. The water content of the product is lower than normal, i.e. it is lower than 0.03% # thus confirming that the cut strands were practically dried perfectly. The feed rate of the cut strands to the dryer is approximately
45 kg / hour, while the thickness of the fluid bed of * strands cut in the perforated area of the spheroidization plate is approximately 10 to 15 mm with application of hot air.

  
In the drying apparatus used, the perforated plate has a width of 450 mm and a length

  
3.200 mm with a drying area of 1.125 m2

  
(450 mm wide and 2,500 mm long) corresponding to the hot air supply chamber below the perforated plate. The remaining part of the spheroidization plate constitutes the perforated area for the passage of the cooling air.

  
In order to ensure security conditions,. this spheroldization plate is designed to dimensions somewhat greater than the minimum dimensions required for spheroidization and drying, this plate comprising small perforations with a diameter of 2 mm dispersed uniformly in its area

  
  <EMI ID = 94.1> of spheroidization at vibrations with a frequency of <EMI ID = 95.1> tion of the mechanical vibration generating device mentioned above. The spheroidization and drying apparatus comprises a hot air supply system and a cold air supply system connected to its respective air supply chambers, as well as an exhaust air system. comprising a cyclone and connected to the air evacuation chamber of the apparatus "As hot drying air, air at a temperature of 150 [deg.] C is used which is projected at a flow speed of 5 m / second through each of the small perforations. The cooling air which is the air of the surrounding medium at room temperature is also projected at a flow speed of 5 m / second through each perforation .

   The drying time and the cooling time are approximately 16 minutes and 5 minutes respectively.

  
Table 3 below gives the characteristics of the cut strands thus obtained compared to the characteristics of cut strands which were obtained by drying the cut strands and impregnated to the same degree in the form of a fixed bed of a thickness

  
of 60 mm having a specific weight of 0.55 to 0.56 g / cm3 and this, for 10 hours with circulation of hot air at 130 [deg.] C.

  
In Table 3, properties such as water content, deposition rate, insolubility,

  
the fluidity value, the specific weight and the lint formation rate are determined in the same way

  
  <EMI ID = 96.1>

  
TABLE 3

  
Characteristics of the strands

  
cut

  

  <EMI ID = 97.1>


  
Although preferred embodiments of the invention have been described using specific terms, this description is given by way of illustration only and it is understood that changes and modifications may be made thereto without departing from the spirit or the scope of the claims below.


    

Claims (1)

1. Process for making high density cut and compressed strands # characterized in that it comprises the steps which consist in preparing flattened cut strands and, while these are impregnated, subjecting them to a rolling effect in order to compress them. 2. Method of manufacturing cut and compressed strands having a high density according to the resale <EMI ID = 98.1> is exerted by subjecting a plate supporting these cut strands to vibrations. 3. A method of manufacturing cut and compressed strands having a high density according to any one of claims 1 and 2, characterized in that it also comprises the step of drying the cut and compressed strands. 4. Method for manufacturing cut and compressed strands having a high density according to one  <EMI ID = 99.1> that it also includes the steps of routing the cut and compressed strands to an area adjacent to one end of a vibrating support plate; transport the cut strands in the form of a fluid bed towards another end of this support plate while applying vibrations to these cut strands, then apply a hot gas to this fluid bed of strands cut from the underside of this bed so that this hot gas flows through this fluid bed to thereby dry the cut strands. 5. A method of manufacturing cut and compressed strands having a high density according to claim 4. characterized in that it also comprises the step of applying a current of a gas for cooling this fluid bed of strands cut, by the underside of this bed, in an area located downstream from that where the hot gas is applied, this cooling gas * flowing through this fluid bed in order to cool the cut strands. 6. Method of manufacturing cut and compressed strands having a high density according to the resale  <EMI ID = 100.1> impregnated and flattened are conveyed to an end region of a vibrating support plate, while they are transported to another end region in the form of a fluid bed, while applying vibrations., the rolling effect being exerted on these strands cut during transport,  <EMI ID = 101.1> and tablets having a high density according to claim 1, characterized in that a hot gas is applied to the bed of cut strands flowing towards the other, the aforementioned end of the support plate and this, by the underside of this reads so that it passes through the latter and thus ensures the drying of the cut strands. 8. Method of manufacturing cut and compressed strands having a high density according to the resale  <EMI ID = 102.1> This layer of cut strands flowing towards this other end of the support plate is applied to an area located downstream from that where the hot gas is applied, by the underside of this bed so that this gas cooling flows  <EMI ID = 103.1> cut. 9, A method of manufacturing cut and compressed strands having a high density according to any one of claims 6 and 7 3 characterized in that the hot gas is supplied to an area of the bed. fluid which is spaced, by a predetermined distance and downstream from the point where the cut and impregnated strands are routed, 10, A method of manufacturing cut and compressed strands according to any one of the claims.  <EMI ID = 104.1> routed to the area of the cut strand fluid bed which is located near the feeding point of the cut and impregnated strands, 11. Apparatus for manufacturing cut and compressed strands having a high density, characterized in that it comprises a rolling apparatus having an inlet for receiving the cut and impregnated strands, a rolling element having a rolling effect on the strands cut and impregnated to compress them, as well as an outlet to evacuate the treated cut strands, 12. Apparatus for the manufacture of cut and compressed strands having a high density according to claim 11, characterized in that the element of  <EMI ID = 105.1> to support the cut strands routed, as well as a vibration generating device for  <EMI ID = 106.1> 13. Apparatus for the manufacture of cut and compressed strands having a high density according to any one of claims 11 and 12, characterized in that it also comprises a drying element designed to receive the cut strands coming from the element of rolling, as well as for drying these strands, 14. Apparatus for the manufacture of cut and compressed strands having a high density according to claim 13, characterized in that the drying element comprises an envelope having, one of se. ends, an inlet for the cut strands and, at its other end, an outlet for the latter; a perforated plate on which is deposited the fluid bed of cut strands and which is situated practically horizontally in the aforementioned envelope between the two ends, this plate comprising several small perforations, while it divides the interior space of the envelope in at least one gas supply chamber situated below this perforated plate and a gas discharge chamber situated above the latter;  a vibrating element intended to vibrate this perforated plate so that the cut strands conveyed by the aforementioned entry are moved towards the exit undergoing vibrations; a hot gas supply element for supplying hot gas into the gas supply chamber so that this hot gas flows upward through the perforations in the perforated plate and then through the fluid bed of cut strands; as well as a gas evacuation element through which this gas is evacuated via this gas evacuation chamber, 15. Apparatus for the production of cut and compressed strands having a high density according to  <EMI ID = 107.1> also a second gas supply chamber located below the perforated plate and on the downstream side of the first gas supply chamber, seen in the direction of flow of the cut strands; as well as a cooling gas supply element for conveying a cooling gas in this second gas chamber so that this cooling gas flows upward through the small perforations made in this plate, then through the fluid bed of cut strands. 16.  Apparatus for the production of cut and compressed strands having a high density according to claim 11, characterized in that the rolling element comprises an envelope having, at one of its ends, an inlet intended to receive the cut and impregnated strands and, at its other end, an outlet for the latter; a perforated plate on which is deposited the bed of cut strands and  <EMI ID = 108.1> inside of this envelope between the two ends, this plate having several perforations, while it divides the interior space of the envelope into at least one gas supply chamber situated below this perforated plate, and a gas discharge chamber situated above this plate; a vibrating element intended to vibrate this perforated plate so that the cut strands routed via the aforementioned entry, are moved towards the exit along this perforated plate taking the form of a fluid bed and while undergoing vibrations ; a hot gas supply element for conveying hot gas into the gas supply chamber so that this hot gas flows upward through the perforations in the perforated plate, then through the bed cut strand fluid; as well as a gas evacuation element in view &#65533; to evacuate this gas via the evacuation chamber gas, the cut strands thus being subjected to rolling and compression, then to drying as they move along this perforated plate. 17. Apparatus for the production of cut and compressed strands having a high density according to claim 16, characterized in that it also comprises a second gas supply chamber disposed below this perforated plate and on the downstream side of the first supply chamber  <EMI ID = 109.1> pés; as well as a gas supply element cooling gas to convey a cooling gas into the second gas supply chamber so that this cooling gas flows upward through the perforations of the perforated plate and then through the fluid bed of cut strands, 18. Apparatus for the production of cut and compressed strands having a high density according to  <EMI ID = 110.1> terized in that the perforated plate on which the bed of cut strands is deposited has a non-perforated zone located near the entrance, this non-perforated zone being designed to mainly exert the rolling effect on the cut and impregnated strands moving through this area, compressing these cut strands. 19. Apparatus for the manufacture of cut and compressed strands having a high density according to any one of claims 16 and 17, characterized in that the perforated plate comprises the perforations practically over the entire extent of its zone &#65533; so that the cut and impregnated strands therein  <EMI ID = 111.1> of rolling.