FI58114B - FOERFARANDE OCH ANORDNING FOER AVLAEGSNANDE AV FOERORENANDE AEMNEN UR EN PROCESS FOER FRAMSTAELLNING AV FIBER A THERMOPLASTIC MATERIAL GENOM UTDRAGNING MED HJAELP AV GASSTROEMMER - Google Patents

Description

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Patent · och ragifterstyralaan AnaMcan udagd oeh utUkrtftan pubUcuratf 29.08.80 (32) (33) (31) * n * «* r Utuellwu» —BagM prlorkat 10.10.73

France-France (FR) 7336169 (71) Saint-Gobain Industries, 62, Boulevard Victor Hugo, 92209 Neuilly-sur-Seine, France-France (iR) (72) Marcel Levecque, Saint-Gratien, Marie-Pierre Barthe, Clermont ,

Jean Battigelli, Rantigny, France-France (FR) (74) Berggren Oy Ab (54) Method and apparatus for removing contaminants from a process for the production of fibers from a thermoplastic material by gas jet stretching - Förfarande och anordning för avlägsnanöe av förorenande av en process fibrers of a thermoplastic material genome utilized with a gas meter

The present invention relates to a method for removing contaminants from a process for producing fibers from a thermoplastic material by gas jets by stretching to form a stream of stretchable gas and stretchable fibers in a forming zone having a perforated receiving device at the boundary of the forming zone. accumulate to form a mattress.

The process according to the invention makes it possible, at least for the most part, to remove pollutants which are harmful because of their toxicity, odor or opacity and which are contained in the gas or liquid waste streams discharged by mineral fiber mat production plants.

The invention also relates to an apparatus for carrying out said cleaning method.

The binders commonly used in this production are based on pure or modified phenolic plastics or amino plastics, as they have advantageous properties for the production of bonded fiber products. They are thermosetting, water soluble or 2,5114 emulsifiable, adhere well to fibers and are relatively inexpensive.

Binders are generally used dissolved or dispersed in water to which certain ingredients are added to make an adhesive to be sprayed onto the fibers.

Due to the heat applied to them during the production process, these adhesives release volatile substances which, even at very low concentrations, have toxic and remarkably bitter odors, such as phenol, formalin, urea, ammonia, and decomposition products of organic substances.

For some uses, other binders are used due to their low cost. Certain natural products harden by reticulation, such as linseed oil when oxidized. Some are thermoplastic, such as bitumen. All of these are exposed during the gluing process of the fibers, at least in part, to a temperature sufficient to cause the release of volatile substances which are harmful e.g. because of its smell.

In this specification, the term binder means any and all of the above binders used in liquid form, dissolved or suspended in water or another liquid, or as emulsions.

The invention relates to the part of the plants for the production of bonded fiber products, which is called the receiving part and which is located immediately after the fiber production plant and in which the following work steps are mainly performed: transporting the fibers from the fiber production plant to the mattress forming member; -gluing of fibers with a binder, which usually contains contaminants; -forming the mattress on the receiving member, which generally has a permeable belt; -cooling of fibers and traction or control media, usually with air sucked by them; -separation of the fibers and (according to which absorbent drawing or guiding) media by sucking the media through the mattress during this formation; -removal of all substances from the plant that are not retained by the fiber mattress.

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It is in this receiving section that large amounts of gaseous media and water come into contact with the binder containing contaminants and are contaminated through a contamination process common to all known methods of making binder-bonded fiber mats, mattresses or sheets, which will now be explained.

a) Exhaust gas contamination takes place according to the following process.

The binder is injected into the stream of fibers and medium leaving the fiber making apparatus as a mist formed by small droplets. Part of the binder adheres to the fibers, another part is deposited on the walls of the device and a third part finally gets into the gas as small droplets and steam.

Thus, the medium is contaminated simultaneously in two ways, namely due to the binder droplets on the one hand and the binder vapors on the other hand. In fact, the binder dispersing and spraying devices used deliver particles, i.e., droplets, over a fairly wide range of diameters. The fibers do not then trap the smallest droplets, but these pass through the fiber mattress during its formation with the stream of medium in which they remain suspended.

The binder droplets deposited on the fibers during the gluing step are exposed to the kinetic effects of the current flowing through it during the formation of the fiber mattress. A considerable number of droplets tear off the fibers and pass through the mattress suspended in the effluent.

In addition, the tendency to cause the binder to be evenly distributed in the mattress forces the binder to be sprayed into the fiber and medium stream in an area close to the fiber fabricator and where the geometry of this stream is still well defined, but where the temperature may be so high that the binder is partially or at least volatile. parts evaporate. These contaminating fumes mix with the medium, contaminating it.

In this specification, "exhaust gases" are hereinafter referred to as "exhaust gases" which pass through a fiber mattress and which are removed during reception, i.e. a combination of traction or control media, a medium absorbed by them, and contaminants in the form of droplets or vapor suspended in these media.

(b) The tasks performed by the water at the receiving stage make significant pollution inevitable.

Water is used for the following purposes: - to dilute and transport the binder when used as a liquid; - flue gas scrubbing, which comprises the following steps: - the aim is to capture as much of the pollutant in the form of droplets or vapor as possible in the form of droplets or steam and thus to transfer the polluting part of the flue gas to the scrubbing water; and - the fibers suspended in the exhaust gas are captured and transported between the walls of the receiving part; - the various parts of the receiving plant (permeable belt, exhaust pipes, etc.) are washed to remove the binder and fibers deposited on them.

During these work steps, dissolved, insoluble or gaseous binder components accumulate in the wash water and its contaminant content can reach high values.

The above explanation of the exhaust and water contamination process is based on the interpretation of measurements and observations made at the manufacturing plant.

The explanation is presented for informational purposes; other explanations may be provided regardless of the method of the invention.

In all plants for the production of bonded fiber products, and regardless of the fiberization method used to produce the fibers in these plants, the contamination process of the effluents described above involves significant effluent volumes.

In plants equipped with a blown fiber traction device in which the material to be drawn is converted into fibers by high-energy jets, the amounts of exhaust gases removed to the atmosphere in the best known methods are in the order of magnitude indicated by the following figures: 5 58114 to 100 Nm-5 per kg of fiber : No. 2,133,236 in the method described; - 300 Nm ^ per kg of fiber in the AEROCOR process described in U.S. Patent No. 2,489,243; 70 Nm ^ per kg of fiber in the SUPERTEL method described in French Patent Publication No. 1,124,489; which in large production plants means 500,000 to 1,000,000 Nm ^ / h.

In plants equipped with fiber drawing devices in which the material to be drawn is converted into fibers by mechanical, e.g. centrifugal, forces and a gas stream is used to convey the produced fibers in a generally substantially horizontal direction to the receiving member, the amount of exhaust gases is slightly lower; for example, in the process described in U.S. Patent No. 2,577,431, it is 30 Nm 2 per kg of fiber, which in the production plant means on the order of 300,000 to 400,000 Nm 3 / h.

The amounts of contaminated water are approximately the same in all methods, 3 namely in the order of 1000 m / h and even in large industrial plants.

The magnitude of these contaminated effluents has led the legislature to first limit the phenolic content of effluents discharged into the atmosphere and then, at least in some countries, to ban the discharge of pollutants altogether.

In addition, there are restrictions on the odor or opacity of discharged effluents in different countries.

The fact is that plants for the manufacture of bonded fiber products are also polluting in this respect, because, in addition to toxic and foul-smelling products, they emit large amounts of water vapor, on the order of 20-30 tonnes per hour, in large plants leaving chimneys as opaque chimneys.

Noise is another disadvantage caused by plants for the manufacture of bonded fiber products. In these plants, noise is generated essentially from two sound sources, namely the fiber production equipment and the exhaust fan.

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In fact, all production equipment installed in these plants uses either high-velocity fluid jets to either convert the drawn material into fibers or to direct the manufactured fibers.

It is known that the level of sound energy produced by these jets increases considerably with their speed. This level may exceed 100 decibels near the fiber manufacturing facility where the operator must perform his work. This level is much higher than the level allowed by the legislature.

In addition, the sound energy of the exhaust fan is transferred along the connecting lines to the degassing chimney. When this is located outside the buildings, it acts like an antenna and radiates this sound energy into the environment. The inconvenience this has caused the neighborhood has led the authorities in various countries to order some institutions to close down.

It has become increasingly necessary to reduce or eliminate the resulting pollution at such a low cost that it does not affect the price of the final product too much; a lot of work has been done to this end and some results have been achieved.

The method according to the invention is characterized by spraying water and a resinous fibrous binder into the gas and fiber stream in the forming zone, recirculating the gas deflected downstream of the receiving apparatus into and through the receiving zone and separating water and solids from the receiving apparatus. , separating the solids from the separated water and re-using the water purified from the solids to spray the stream of gas and fibers in the formation zone.

The device according to the invention is characterized in that it has a device which sprays a liquid binder compound into a stream of gas and fibers in the forming zone, a suction fan connected to divert gas from the suction chamber, a device separating liquid binder components a device for recycling the liquid components and reusing them in the spray binder compound, and a device for recycling the gas discharged from the suction chamber to the forming zone and through the fiber collecting device after the liquid binder-containing components have been separated.

7 58114

According to the invention, it is precisely most of the exhaust gases that are recycled back to the plant and only a small part of them are treated and removed, so that the amount recycled can be at least 95% of the total amount of exhaust gases normally released into the atmosphere. The amount of gases to be purified before removal can thus be less than 5% of their total amount, which makes it possible to use a cleaning treatment which is expensive but has a perfect efficiency, such as incineration, without excessive energy costs.

Another object of the invention is to render water-curable thermosetting resins insoluble. This is achieved by heat treatment, preferably above 100 ° C, most preferably between 150-240 ° C. This heat treatment can advantageously be carried out under pressure.

This application of the insolubilization process to at least a part of the cooling and washing water is preferably used to insolubilize the dissolved binder components contained therein, so that they can then be separated by known techniques and thus keep the washing and cooling water contaminants so low that they can be reused in the plant. The wash water then circulates in a closed circuit so that no contaminants are released through it.

The invention also relates to a heat treatment which is carried out on the washing water and which comprises evaporating this and heating the steam to such a high temperature that the contaminants become uncontaminated.

The invention also provides isolation devices adapted to the specific shapes of the recirculated exhaust gas conveying and control devices, in order to reduce the noise caused by the fiber manufacturing devices, and a special arrangement of the non-recycled exhaust gas exhaust device which reduces the noise emitted to the environment.

Other objects and advantages of the invention, including in particular many specific advantages in exhaust gas recycling, are set forth and explained in more detail below.

8 58114

Figure 1 shows a type of receiving device to which the invention is directed.

Fig. 2 shows a part of a device of the type according to Fig. 1, in which, however, the walls delimiting the receiving chamber are extended to the fiber manufacturing device.

Figure 3 shows a receiving device according to the invention.

Figure 4 shows another embodiment of the device according to the invention. Figure 5 shows another embodiment of the washing chamber.

Figure 6 shows the evolution of the insolubilization treatment yield as a function of temperature and treatment time.

Figure 7 shows an apparatus in which heat treatment of water under pressure according to the invention can be carried out.

Figure 8 shows a continuous water treatment device.

Figure 9 shows an apparatus in which one of the solid waste heat treatments according to the invention can be performed.

Figure 10 shows an apparatus in which a second solid waste treatment method can be performed.

Figure 11 shows a complete receiving plant according to the invention which can be used for the production of fiberglass sheets.

Figure 12 shows an embodiment of the invention applied to another method of manufacturing glass fibers.

Figure 13 shows another embodiment of the invention applied to a method of blowing mineral fibers.

Figure 14 shows another embodiment of the invention applied to a method of manufacturing mineral fibers, in particular slag fibers.

Figure 1 shows a receiving plant of the prior art type to which the invention relates. This plant includes: -Fibre manufacturing apparatus 11 of a known type, commonly used in bonded fibreboard manufacturing plants, in which the material to be drawn is exposed to centrifugal or aerodynamic forces or both. The aerodynamic force is applied to the material to be drawn or to the fibers by jets, which are generally high in temperature and high in speed. The resulting fibers leave the device dispersed in a medium stream 12, which is generally in a gaseous state and consists of high energy jets, as well as media which they absorb from the environment and which surrounds the fibers and directs them in a well-defined stream towards the receiving member.

9 58114 - A gluing zone located in the path of the fiber and medium flow between the fiber manufacturing device 11 and the receiving member, where the atomizers 13 spray the binder as a small droplet mist into the fiber and medium stream. A significant proportion of the droplets hit and adhere to the fibers and the rest are suspended in the gases accompanying the fibers, either as droplets or in the form of vapor.

- A fiber splitting device 14 timed in the path of the fiber and gas stream 12 either between the manufacturing device 11 and the gluing zone or between the gluing zone and the receiving member as in Figure 1, which by vibrating the fiber and gas stream distributes the fibers to the receiving member so as to form a mattress.

- A receiving member 15 formed by an endless, perforated belt on which the fibers descend to form a mattress.

- A box 16 placed under a perforated belt on which the fibers are deposited, i.e. a mattress forming zone where the vacuum generated by the vacuum cleaner 19 forces all the gas traveling with the fibers on their way from the manufacturing device 11 to the torn belt 15 to pass through the forming mattress without gaseous medium at all travel with the fibers out of the mattress formation zone.

- Vertical walls 21 extending from the torn belt 15 to a level close to the fiber making device 11 and delimiting the mattress forming zone so as to form a chamber 22 surrounding the fiber and gas flow, open at the top, to the zone close to the fiber making step, now called that is, as a chamber.

- A vacuum cleaner 19, the function of which is to generate a sufficient vacuum in the box 16 to pass the entire amount of gas entrained with the fibers, as they deposit on the receiving member, through the forming mattress, and which removes the gases into the atmosphere through the chimney 5.

It has already been mentioned above that the amount of gases to be removed from the receiving device La of the type described above is quite large.

Thus, in fiber fabrics equipped with these devices, in which jets of media are used to draw or control the material to be fiberized or to control the fibers, their flow rate and velocity are very high.

This speed, which is usually more than 100 m / sec, is much higher than the speed that the fibers and the accompanying gases, if a proper mattress is desired, must have when they arrive at the receiving member, which speed usually does not exceed 10 m / sec. Therefore, the speed of the jets leaving the fiber manufacturing device must be significantly slowed down. This is accomplished by transferring a plurality of motion of these jets to a medium with which they are allowed to coalesce, which they themselves absorb and accelerate in their own flow direction, and into which they mix. It is this mixture of the jets leaving the fiber making device and the medium which they absorb that forms the flow which accompanies the fibers.

The suction of the medium from the environment by the jets leaving the fiber production device is a well-known phenomenon and is characteristic of all jets flowing in the open air or in a space containing some medium. Indeed, according to medium mechanics, it is known that such a jet absorbs a considerable amount of medium from the environment, and that these sucked amounts of medium increase from the point of origin of the jet along its length as it travels in the surrounding medium. But since this suction phenomenon is a progressive phenomenon, the velocity of the suction jet does not decrease much until the jet has traveled a long enough distance in the ambient air.

In plants of the type described above, in order to have the above-mentioned velocity of the flow of fibers and accompanying gas to the receiving member (on the order of 10 m / sec or less), the distance from this fiber making device 11 to the receiving member 15 is generally greater than 2-3 meters. the amount of medium which the jets leaving the defibering device 11 suck in this way and which passes through the receiving member 15 is at least 10-20 times compared to the amount of medium which forms the jets and leaves the defibering device 11.

In addition to slowing the flow of fibers and subsequent gas, in order to provide good conditions for mattress formation, it is necessary that the flow directions of fibers and gas be parallel and generally directed from the defibering device to the receiving member.

To illustrate the matter, the transverse slices of the fibers and the subsequent gas stream 12, bounded by intersecting planes perpendicular to the flow direction and represented by the lines M, N, 0, are considered below.

The foregoing knows that in all slices bounded by straight shear planes such as M and N, the current retains its direction well defined and undergoes a well-defined rate-loss.

These two factors, direction and velocity loss, are of the desired nature in each stream slice if the current is able to uniformly absorb the entire required amount of medium relative to the entire circumference of the slice relative to the mass of the forming medium as it enters the shear plane M and its relative velocity loss occurs as it passes through the MN of the slice in question.

This relative velocity loss is equal to the ratio of the difference between the speed of the incoming current at the cutting plane M and the velocity of the outgoing current at the cutting plane N to the former speed.

If the surrounding medium in all slices of stream between the defibering device and the receiving member is able to deliver to each of them the amount of medium necessary for the flow direction and velocity loss to be desired, the suction stream of the surrounding medium is formed downstream of the fibers and subsequent gas. This current is shown in Figure 1 by lines 27 ·

In the receiving plant of the type according to Figure 1, the medium sucked by the stream 12 consists entirely of atmospheric air coming into the housing 22 from a large opening 28 in the housing 22 in the area at the defibering device 11.

Figure 2 shows the shape of the medium flow in the receiving chamber when the environment is unable to deliver to the jets leaving the defibering device the full amount of medium which they could absorb. This shape is shown in an illustrative sense for ease of presentation.

This Figure 2 shows a part of a receiving plant comprising a fiberizing device 11 from which a fiber and gas stream 12 leaves, a gluing device 13, a fiber breaking device 14, a receiving member 15 and a vacuum box 16 into which the exhaust gases 29 flow after passing through the forming nozzle 23 . All these members are similar to Fig. 1. Instead, the walls 21 delimiting the receiving chamber 22 are extended in Fig. 2 to the defibering device 11, so as to considerably reduce the opening 28 through which the chamber 22 communicates with the atmosphere and thus the amount of atmospheric air entering this chamber. .

Thus, if in one of the slices of the current 12 and especially in slices such as IV! and N located in the zone close to the defibering device 11, i.e. near the nozzles of the guiding or drawing jets of the material to be defibered or where the velocities of these jets are at their highest, the environment is unable to deliver to the fiber and subsequent gas stream 12 the full amount of medium that the stream could absorb, in which case the missing medium slices located downstream, such as slices 0 and P, where the speed of stream 12 is lower.

The gas streams 30 leaving the zones downstream of the main gas stream rise all the way up the walls 21 to the upstream, faster flowing zones, enter the main stream and accelerate in the general flow direction. This creates vortices 31 which develop between the interfaces of the current 12 and the walls of the chamber 21. The intensity of these vortices increases the greater the amount of medium that the environment has been unable to release; their direction of rotation is such that the fibers which they tear from the forming belt 23 and carry with them are guided along the walls of the chamber 21 towards the dispensing device 14, the gluing device 13 and the defibering device 11.

Thus, if the amount of atmospheric air entering the receiving chamber of the plant of Figures 1 and 2 decreases to a value 58114 much less than the amount of air that the current could absorb, the intensity of the vortices 31 may be so high that the fibers it carries are entangled in the defibering and gluing equipment and interfere with their operation. In addition, these vortices may disorder the emerging mattress 23 as shown in Figure 2.

In the industrial use of this type of plant, it has been shown that this phenomenon of fiber rise, called recovery, is permissible as long as the amount of air entering the chamber is less than 60-70% of the required amount. Below this value, use is no longer possible industrially. If it were desired to further reduce or eliminate the amount of atmospheric air entering the chamber, the turbulence in the chamber would be so strong that the fibers could not settle on the receiving member.

It is an object of the invention to provide a method by which the amount of atmospheric air entering the receiving chamber can be considerably reduced or completely eliminated, while maintaining the conditions suitable for the formation of the mattress.

This method comprises not using atmospheric air as the suction medium, but a part of the exhaust gases which are removed from the pressure side of the blower, i.e. some of the exhaust gases continuously passing through the receiving chamber are returned, i.e. recycled back to the chamber.

An apparatus suitable for carrying out this method is shown in Figure 3. * The receiving chamber 22 is closed at the top by a lid 32 with a hole through which the flow of fibers and the subsequent gas 12 from the defibering device 11 enters the chamber 22. The edges 33 of this opening are tangential to the current 12 and have a shape to facilitate the flow of said current.

To facilitate utilization, the lid 32 may be located at a distance H from the defibering device 11.

The device according to Figure 3 comprises a washing chamber 17 located downstream of the vacuum box 16 and having a generally larger cross-section than this, and is provided with devices in which the exhaust gases 29, i.e. the gases following the fibers between the defibering device 11 and the receiving member 111 58114 15 and the contaminants suspended therein are brought into contact with a detergent, namely water. In this scrubber 17, the substances contained therein suspended in the exhaust gases are separated, which consist essentially of fibers and a binder which has adhered to the fibers as they pass through the gluing zone and the fiber mattress being formed. When the fibers contained in the exhaust gas come into contact with the wash water, they are trapped by small water droplets, so that they then tend to settle to the bottom of the chamber 17 by gravity, a phenomenon further accelerated by the high flue gas velocity loss due to the flow cross-section from contaminant droplets or fumes, wash water droplets are captured and dissolved by themselves. Exhaust gas scrubbing consists of a combination of these two operating steps. The scrubbing water to which at least part of the exhaust gas contaminant content has been transferred is discharged through the opening 24.

The device further comprises a vortex or electrostatic separation system 18 located between the scrubber chamber 17 and the fan 19, in which at least some of the water droplets transferred to them during the scrubbing process are separated from the exhaust gases, which is important to remove before the vacuum cleaner 19. The liquid water separated from the exhaust gases

The collector 26 directs the wash water removed from the openings 24 and 25 to their treatment zone.

The fiber and gas stream passes through the gluing device 13 and then the fiber dispersing device 14. The fibers are deposited on the receiving member 15 and the exhaust gases pass through the emerging fiber mattress 23, the box 16, the washing chamber 17 and the water separator 18, and are blown by a fan 19 into the line 34. Some exhaust gases are discharged from the system through the opening 35. The second part is led along the line 34 to the receiving chamber 22, into which it passes through an opening 36 located in the area at the defibering device 11.

The amount of soot entering the receiving chamber through the opening 33 is equal to the amount of gas coming from the defibering device 11 plus the amount of air 27 which this gas absorbs as it travels in free air on the journey H. The amount of gas entering the chamber increases.

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In order for the system to be in equilibrium, the amount of exhaust gas leaving the system through the outlet 35 must be equal to the amount of gas entering the system through the opening 33. However, the amount of gas to be removed decreases as the distance H decreases.

Figure 4 shows a particular embodiment of the invention in which the distance H is zero, i. wherein the defibering device 11 or at least the outlet nozzles of the traction or control jets are located in the chamber 22. The amount of gas removed from the system is quite exactly equal to the amount of medium leaving the defibering device 11. The amount of recovered exhaust gas in this embodiment is at least 96-97%>

The amounts recycled in the plants according to the invention shown in Figures 3 and 4 correspond to the amounts which the jets of the device 11 are able to absorb, whereby the flow of medium in the chamber 22 takes place completely in the flow direction of the traction jet without disturbing vortices. Recycled exhaust gases essentially follow the streamline and 37.

One of the advantages of the invention is that the exhaust gas streams 37 recirculated by the fan 19 can be given a slightly higher velocity than the atmospheric air stream 27 whose fibers are sucked in by the gas stream 12 in the plants according to Figure 1. The currents 37 thus have sufficient energy to resist a possible tendency for the fibers to rise.

The main advantages of the method according to the invention are that the amount of exhaust gas to be removed from the system can be made as small as 3-4% of the conventional exhaust amounts of the above-mentioned order of magnitude, and that this small amount of exhaust gas can be subjected to expensive but efficient cleaning treatment.

Thus, the exhaust gases removed through the opening 35 are treated by incineration, which step comprises raising the temperature of the exhaust gases above 600 ° C, above which the exhaust gas contaminants, in particular phenolic compounds, on combustion become contaminated tower compounds such as CO 2 and H 2 O. This treatment also has the advantage of eliminating odors. The combustion is carried out in a device 38 of a known type, consisting of a combustion chamber 39 »a bulb 40 into which a combustible mixture is fed and a flame stabilizing member 41 known per se. The treatment temperature can be raised between 300 and 400 ° C in the presence of a combustion catalyst.

The purified exhaust gases are discharged into the atmosphere through the chimney 42. At the outlet end of the chimney 42, the temperature of the exhaust gases is so high and, due to their recirculation, their amount is so small that the water vapor they contain does not condense until the exhaust gases have completely decomposed into the atmosphere. Thus, there is no opaque cloud at the mouth of the chimney 42.

The invention also has the advantage that since the exhaust gases are either recycled or subjected to a complete cleaning treatment, they do not have to be washed very completely beforehand, which makes it possible to reduce the dimensions and investment costs of the washing device 17 and the water separation device 18 before the extractor.

The plants according to the invention shown in Figures 3 and 4 comprise a gluing device and a receiving chamber 22 surrounding the fiber breaking device, which makes these devices difficult to access. However, if during operation it is necessary to break into the gluing device 13 or the fiber dispersing device 14, the hatches in the walls of the chamber close to the defibering device 11 must be opened for this purpose.

If during this delivery it is desired to prevent the return gases, which are therefore not completely purified, from escaping from the chamber 22, the pressure inside this must be equal to or less than the atmospheric pressure of a few millimeters of water (1-2 mm VP).

This also has the advantage that, when the inspection hatches are closed, unintentional leaks caused by defective sealing are completely avoided. The pressure in the chamber 22 is adjusted to the desired value by setting the vacuum generated by the fan 10 in the box 16 in the embodiment according to Fig. 3.

Another way is that the amount of exhaust gas to be removed is removed, not through the return line 34, but directly into the chamber 22 through an opening 43 in the wall of the chamber in the zone where the pressure must be maintained at the desired value, as shown in Fig. 4. The exhaust gases are removed from the chamber 22 by a small auxiliary fan 44 and 17 581 1 4 are led out along the line 35. The fan 19 then does nothing but recycle the exhaust gases. This embodiment makes it possible to position the vacuum or zero pressure zone more precisely.

One advantage of the invention is that the amount of finely divided binder sprayed by the guns 13 can be adjusted according to the amount of binder components suspended in the recycled exhaust gases that accumulate in the fiber mattress as the exhaust gases pass therethrough.

In fact, recycling causes the exhaust gases to pass repeatedly and densely through the emerging fibrous mattress, and although this mattress has poor trapping ability due to the low exhaust gas velocity, the number of successive passes is so high (about 15 times per minute) that the amount of binder components in the exhaust gases remains on the mattress. As a result, the amount of finely divided binder fed through the gluing device 13 can be correspondingly reduced, which makes it possible to increase the efficiency of the binder by about 5 #, which is an economic advantage to be taken into account.

In the plant according to Figure 1, the temperature of the receiving chamber 22 must be maintained at a certain value and therefore the heat introduced to it by the material to be drawn and the traction or control medium must be removed. In fact, since the binder used for gluing the fibers is thermosetting, it undergoes a continuous development under the influence of heat, which gradually changes it from the liquid state in which it is sprayed to a solid state. If the temperature in the chamber 22 is too high, the binder may reach a stage of development during mattress formation that is long enough to alter its ability to bind fibers. This phenomenon is called pregelatinization and is avoided by cooling the receiving chamber 22.

In the plant according to Figure 1, this cooling takes place by means of the absorbed atmospheric air, the temperature of which is generally lower than the maximum temperature allowed in the chamber 22. The amounts of heat which enter the chamber and the traction or control medium and which, depending on the method of defibering, are of the order of 1500 to 15 000 Kcal per kilogram of material, are transferred to the intake air and then to the exhaust gases, which give off a small proportion. in contact with the washing water, and remove the rest of them with them into the atmosphere.

In the plant shown in Figures 3 and 4, a small amount of exhaust gas removed to the atmosphere removes only a small amount of heat, so that a second method must be used to cool the receiving chamber 22.

The invention provides such a method. The method comprises transferring at least a portion of the heat introduced into the chamber 22 by the material to be drawn and the traction or control medium to the heat exchange medium, namely water, by contacting the stream of flux and subsequent gas or exhaust gases with this medium. The heat exchange medium, after absorbing the heat introduced into the chamber 22, is removed from this chamber and cooled by a suitable system located outside the plant.

The heat exchange between the fibers and the subsequent gas stream or exhaust gases and cooling water is carried out by contact between the media, either directly or through a heat-conducting wall separating them. It is known that the amount of heat exchanged per unit time in this heat exchange mode is proportional to the temperature difference and the contact area of the medium to be cooled and to be cooled.

The relatively low velocities of the gas or exhaust gas, taking into account the dimensions of the plant, result in the short time available to carry out the heat exchange. In order to have sufficient cooling, the amounts of heat exchanged per unit time must therefore be large.

The invention provides methods and apparatus for this purpose.

One of these methods involves removing from the receiving chamber 22 the heat units introduced therein by the material to be drawn and the traction or control medium by cooling the exhaust gases in a box 16 and a scrubber chamber 17 where available volumes allow large contact surfaces between the cooling water and the exhaust gases. A large contact surface can be achieved in many ways: either by dispersing the water in the form of small droplets or making it flow in the form of a very thin film, or finally by bubbling the exhaust gas into the water.

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For example, in the apparatus of Figure 3, the atomizers 45 spray cooling water in the form of small droplet membranes, i.e. curtains, which are located substantially perpendicular to the flow direction of the exhaust gases 29. After passing through the emerging fibrous bed, the exhaust gases enter the box 16 at a temperature of the order of 80-100 ° C and are cooled by contact with water curtains to a temperature of the order of 10 ° C. The temperature of the water entering the sprayers 45 is of the order of 15-20 ° C, depending on the cooling equipment available. In contact with the exhaust gases, the water heats up to a temperature of the order of 30-40oC, depending on the power of the nozzles 45.

The recyclable portion of the cooled exhaust gases passes through a separator 18 and a fan 19 and then enters a receiving chamber 23 where, mixed with the gas from the defibering device 11, it cools this gas and fibers in the same way as atmospheric air enters the device of Figure 1.

Another embodiment is shown in Figure 4, where water flows along the partitions 46 as a very thin film. The exhaust gas stream 29 travels along these partitions, licks the water film and cools upon contact with it.

Yet another embodiment is shown in Figure 5. In this device, the exhaust gas stream 29 penetrates through the nozzle 47 below the free surface of the water mass 48 located downstream of the vacuum box 16, generating strong turbulence in this water mass to the right of nozzle 47. and for contacting the exhaust gases.

Yet another method comprises removing from the receiving chamber 22 the heat units introduced therein by the material to be defibered and the traction or control medium by immediately cooling the fiber and gas stream 12 by injecting water therein. Water injection into this stream is performed in a zone where the contact surfaces cannot be quite large because the available space is small, but where the temperature difference between the coolant and the coolant is large.

There are other embodiments. For example, in the embodiment according to Figure 3, the nozzles 49 located between the defibering device 11 20 581 1 4 and the gluing device 13 spray the mist consisting of small water droplets against the stream to be cooled.

The droplets meet in a zone of gas and fiber flow, where this is at a high temperature, which can be as high as 600 ° C, and evaporate immediately.

The large amounts of heat, in the order of 600-700 Kcal per kg of water to be evaporated, required to vaporize the water droplets are removed from the fiber and gas stream, which then cools very rapidly, reducing its temperature at the level of the gluing device 13 to the order of 100-120 ° C. The generated steam escapes with the exhaust gases through the fiber mattress 23 to the box 16 and the washing chamber 17, where it condenses on contact with the water curtains from the atomizers 45 and transfers its latent heat to the cooling water from the atomizers 45.

The placement of the device 49 injecting the cooling water into the stream 12 between the defibering device 11 and the gluing member 13 is a preferred embodiment of the invention. This arrangement therefore offers certain advantages:

First, it is in this zone that the temperature difference between the stream to be cooled and the water is greatest and, as a result, the heat transfer is greatest.

Second, the spraying of the binder into the cooled fiber and gas stream takes place at a sufficiently low temperature (100-120 ° C) that the pollution of the binder due to the removal of volatiles is very small or non-existent.

This results in an increase in binder efficiency of about 5% and a corresponding reduction in exhaust gas contamination.

Yet another embodiment is shown in Figure 4, in which a device 50 for injecting cooling water into the fiber and gas stream 12 is located between the gluing device 13 and the receiving member 15. As in the embodiment according to Figure 3, the cooling water passes in the form of steam through the mattress 23 being formed. This water condenses, transferring its heat to the water films which flow along the partitions 46 of the washing chamber 17.

21 58114 This water is discharged from the plant through openings 24 and 25 located at the lowest points of the boxes 16 and 17 and the water separating member 18, to a device 51 in which solid particles, in particular fibers suspended in water, are separated from the water.

The device 51 can be either a vibrating or rotating perforated screen of a known type or a decanting or centrifuging device of a known type.

The water from which the suspended solids have been separated is collected in a basin 52 and then led by its own weight or by a pump 53 to a cooling station 54. After this position, the cooled water can be removed to the outside or reused in the system.

Station 54 may consist of a cooling tower 106 of a known type in which water is cooled by contact with air. But if the wash water is immediately cooled in the tower 106, there is a risk that the air will be contaminated with the most volatile contaminants remaining in the wash water.

This danger is small because in this way the amount of pollutants leaving the tower 106 into the atmosphere is less than 5% of the amount leaving the chimney 35 of the non-recycled plant of Figure 1.

In order to avoid this danger, the washing water according to the invention is in any case cooled in a heat exchanger 105, in which the cooling medium is uncontaminated water which circulates in the cooling tower pumped by the pump 107.

According to another characteristic, no water is removed from the plant as a liquid at all, so the remote environment is not polluted by the pollutants contained in the water.

This knows that the cooling and washing water circulates in the plant in a closed circuit.

In the plants according to Figures 3, 4 and 5, the closed circuit followed by the cooling and washing water is as follows: - The water leaving the cooling station 54 is pumped by a pump 55 to the cooling units 49 and / or 50 located in the chamber 22 and the steam condensing and exhaust gas scrubbers located in the chamber 17 and consisting of either the atomizers 45 of Figure 3 or the water-film partitions 46 of Figure 4 or the basin 48 of Figure 5.

- Washing water and condensed steam containing contaminants, fibers and binder components flow through the openings 24 and 25 at the lowest points of the washing chamber 17 and the water separator 18 to a collector 26 which leads them to a filtration device 54 which separates suspended solids, fibers and insoluble matter from the washing water.

This waste is collected on a conveyor 57 · The filtered wash water contains only contaminants and soluble binder components, so it is transferred by gravity or pump 53 to a treatment station 54.

It has been found that when the wash water circulates in a closed circuit, the concentration of substances dissolved or suspended in the filtered water must be kept below a certain value of the order of 3-4%, calculated in units of mass of dry matter per unit mass of water. Above this value, some of the substance dissolved or suspended in the wash water (mainly microfibers or binder microparticles not remaining in the filter device 51, as well as soluble binder components) is deposited on different parts of the plant. The binder polymerizes to form viscous or solid layers which gradually block the holes passing through the washing water spray nozzles 45, 49 and 50 and the exhaust gases 29 of the receiving body 15. This results in a reduction and cooling of the amount of exhaust gases leaving the horn, which will soon lead to a plant shutdown.

Therefore, in order to keep the concentration of substances carried by the water below the desired limit, significant amounts of substances must be removed from the wash water. In fact, a significant portion, on the order of 20-30%, of the binder sprayed onto the fibers by the devices 13 enters the wash water through the process described above. In large plants, this results in 3000-5000 kg of binder per day (calculated as dry matter) entering the closed wash water circuit, so that as much of the binder as it enters must be removed from the water in order to maintain the concentration at equilibrium.

23 581 1 4

Several different removal methods are possible:

One of these methods comprises treating at least a portion of the wash water in a centrifuge capable of separating much smaller suspended solids from the water than the screen 51. The water treated by the centrifuge 58 may be returned to the basin 52, as shown in Figure 3, or more preferably sent to a cooling device 49.

Another method comprises treating the water by adding a flocculant thereto and then separating the flocculant substance therefrom.

The disadvantage of these two methods is that they essentially separate only the insoluble substances it contains from water. The dissolved binder, which makes up the majority of the substances to be removed, remains completely inseparable or separates only slightly.

The invention provides several methods for removing binder dissolved in wash water. .

One of these methods comprises using screened or centrifuged wash water to dilute the binder with gluing devices 13 in the manufacture of adhesives to be sprayed onto the fibers. The screened water can be taken from any point in the circuit from the downstream side of the cooling station 54 or more preferably from the downstream side of the centrifuge 58, as in Figure 3, through the valve 59.

Another method comprises using the washing water as a cooling medium for the fiber and gas stream 12 in the chamber 22. The washing water is then injected into the stream 12 by the cooling device 49 of Fig. 3 or by the cooling device 50 of Fig. 4.

These two methods have the advantage that part of the binder contained in the wash water can be reused, and the invention is characterized in that the amount of binder sprayed by the gluing device 13 is adjusted as a function of the amount of binder retained by the mattress 23 with the devices 49 or 50. makes it possible to improve the efficiency of gluing, but these methods are not able to remove such large amounts of dissolved binders from the wash water that the binder content of this water remains below the desired value. Therefore, the invention provides two methods by which substantial additional amounts of dissolved binder can be removed from water circulating in a closed circuit.

^ 58114

One of these methods comprises burning a small part, of the order of 1-5% of the wash water flow in the circuit, in a suitable device 60. This device, shown in Figure 4, is of a known type and comprises the following parts: - A burner 6l fed with combustible air and fuel mixture; - a spray nozzle 62, from which the water to be treated entering it up the line 63 is sprayed in the form of small droplets under pressure into the flame of the burner 6l by means of a scattering cloth 64; - Reaction chamber 65, in which the washing water is treated under the action of the heat leaving the burner 61. This involves first evaporating the wash water, and then heating the generated steam and water-entrained components to a temperature of the order of 800 ° C, where these contaminating binder components become uncontaminated such as CCl 4 and IVO.

Uncontaminated steam exits through the chimney 66 outside the device at a high temperature so that an opaque cloud does not form.

The water intake to be treated is generally located between the pump 53 and the cooling station 54, as shown in Figure 4.

This method has the advantage that the binder components contained in the treated wash water can be completely removed and converted into uncontaminated compounds. It has the downside that it requires high energy consumption and is very expensive. The effect of processing costs on the price of the fibrous products produced can be reduced by recovering part of the heat of the high-temperature steam in a heat exchanger producing superheated steam for various purposes.

The second method comprises subjecting a small portion of the flow rate of wash water containing dissolved binder of the order of 1-5%> in a closed circuit to heat treatment to render the binder insoluble and then separating it from the water by some suitable separation method such as filtration, flocculation, flocculation, .-

It has been found that if water used for cooling and scrubbing exhaust gases, which after filtration contains dissolved binder or binder components, is kept at a certain temperature for a certain time, the temperature and treatment time increase the dissolved binder to insoluble particles which are then suspended in water and easily separated thence.

The relative amount of part of the solute that becomes insoluble during treatment indicates the efficiency of the treatment.

The processing temperature has a fairly large effect on the efficiency; for example, it has been found that when treating water containing 1% of binder components in solution, the treatment efficiency is: 40% y if the water is kept at 40 ° C for 8 hours, ^ 0% if the water is kept at 70 ° C for 3 hours, ^ 0 % if water is kept at 110 ° C for 3 minutes, 60% if water is kept at 180 ° C for 3 minutes, and 95% if water is kept at 240 ° C for 3 minutes.

Figure 6 shows the development of treatment efficiency as a function of treatment temperature and time.

In large factories producing bonded fibreboards, where the amount of water to be treated can be up to 50 m 2 / h, it is mandatory to strive for the shortest possible processing times and thus to operate at elevated temperatures above 100 ° C in order to avoid the use of oversized treatment equipment. This knows that the treatment must be carried out in a pressure vessel, at a temperature maintained at about 5 ° C below the boiling point of water at the pressure prevailing in the vessel, so that the water remains in the liquid phase during the treatment. This solution also has the advantage that its energy consumption is low and, with the exception of losses, corresponds only to the heat surcharge that must be transferred to the water in order to increase its temperature.

Thus, per the same amount of dissolved binder removed, this method is four times cheaper than the combustion method described above.

26 5 81 1 4

One of the difficulties that usually occurs when heating water in a pressure vessel containing a small amount of binder or its components dissolved is that a layer of insoluble binder forms on the vessel walls which very soon reaches such a thickness that it clogs the emptying openings of the vessel or itself. vessel.

It has now been found that if the heat required for treatment is released inside the water mass to be treated and the walls of the vessel are kept at a lower temperature than the mass of water to be treated during treatment, no deposition on the walls remains and the insoluble binder remains suspended in water. This has resulted in heating the water either by mixing it with hot media such as water vapor, preferably superheated, or the combustion gases of a burner immersed in it, or with devices that place energy inside the water mass, such as by an electric arc.

Operating conditions can vary over a wide range, for example pressure from 6 to 40 bar abs, temperature from 160 to 24 ° C and treatment time from 3 to 10 minutes.

The following operating conditions are the result of a good compromise between energy cost and equipment maintenance costs.

- temperature: 200 ° C

- pressure: 16 bar abs - treatment time: 5 minutes - efficiency: 70-80%.

This form of processing can be performed either intermittently or continuously.

Figure 7 shows a periodically operating device for carrying out this processing method. The water to be treated is fed via a motorized valve 67 to the vessel 68. The amount of water fed, i.e. the charge, corresponds to 70-80% of the capacity of the vessel. The heating medium, which is steam, preferably superheated, is then injected into the vessel by means of an injector 69 »the end nozzle of which is immersed. The amount of steam is controlled by a motorized valve 70 controlled by a controller 71.

The treatment cycle is as follows: 27 5 81 1 4 - Vessel 68 contains a charge of water to be treated at atmospheric pressure.

- The desired treatment pressure is set in the regulator 71, for example 16 bar abs.

The valve 70 opens and the steam flows through the injector 69, mixes with the water to be treated and, as it condenses, transfers all its latent and free heat to it. The temperature and pressure in vessel 68 rise until they reach values of about 200 ° C and 16 bar abs.

In this case, the steam supply is interrupted. The injector 69 is dimensioned so that this rise in temperature and pressure is rapid, lasting less than one minute.

The water is kept at 200 ° C and 16 bar abs for 2-4 minutes.

After this time, the pump 72 is started to pump a new batch of water to be treated through the double jacket 74 into the basin 73. As it passes through the double jacket, the water to be treated, which enters a temperature of about 40 ° C, initiates cooling of the treated water in vessel 68. The double jacket 74 is dimensioned so that the water to be treated enters the basin 73 at a temperature of about 80 ° C.

In the second double jacket 75, additional cooling medium is circulated, completing the cooling of the treated water in the vessel 68. Cooling is considered complete when the temperature of the treated water has dropped below 100 ° C, preferably 40-50 ° C. The motorized valve 76 then gradually opens to relieve pressure from the vessel 68.

The treated water flows to a filtration station 51 or a flocculating, decanting or centrifuging device, which separates from the treated water the binder which has become insoluble during the treatment.

The filtered water flows into the basin 52 and the removed waste 56 is transferred to a conveyor 57 ·

When the vessel 68 is empty, the valve 76 is closed and the valve 67 is opened, allowing the preheated water to be treated to flow under its own weight from the basin 73 to the vessel 68. The drain valve 67a completes the plant.

A new episode can begin.

28 5 81 1 4

Figure 8 shows a continuous apparatus for performing the processing method.

The pump 77 presses the water to be treated at a treatment pressure into a mixer 78, into which a heating medium, namely steam, enters via the injector 79. The steam mixes with the water to be treated and, when condensed, transfers all its heat content to it. The steam flow rate is controlled by a motorized valve 80 controlled by the controller 81 so that the desired treatment temperature is maintained at the outlet of the mixer 78. After leaving the mixer 78, where it has remained for about ten seconds, the water to be treated passes through a reactor 82 where the binder becomes insoluble and which is dimensioned so that the residence time of the water to be treated there corresponds to a treatment time of about 2 k minutes.

Upon leaving the reactor, the water is cooled in a heat exchanger 83 to a temperature below 100 ° C, preferably between 40 and 50 ° C. Part of the cooling is performed by the water to be treated, which thus preheats in the coil 81 from about 40 ° C to about 80 ° C.

The second part of the cooling is performed by a circulating cooling medium in the coil 85.

After the treated and cooled water leaves the heat exchanger 83, its pressure is reduced to atmospheric pressure by a pressure relief valve 86 which, under the control of the controller 87, maintains the plant at the treatment temperature.

The unpressurized water then flows to a filtration device 51 or a flocculation and decantation or centrifugation device, in which a binder which has become insoluble in the treatment is separated from the treated water. The filtered water flows into the basin 52 and the treatment waste 56 is transferred to the conveyor 57 ·

In the continuous device according to Fig. 8, the processing can be performed more flexibly and cheaper than in the device according to Fig. 7.

Another method comprises treating part of the contaminant-containing wash water in a ventilated basin from bacteriological. The bacterial organisms present in such a pool cause the enzymatic pathway to decompose the water, especially phenolic compounds. This treatment causes, in a step corresponding to a complete oxidation reaction, in particular the conversion of phenolic compounds into uncontaminated substances such as CO 2 and H 2 O. For this reaction to be complete, the bacterial organisms and the oxidation reaction must be supplied with the necessary oxygen by aerating the pool.

Bonded fiberboard manufacturing plants generate a large amount of different types of waste, all of which, however, contain a contaminating binder or binder component.

These are, firstly, Manufacturing Waste, which are discarded boards in quality control. These wastes contain contaminants in a dispersed form, but are very space consuming. Then there are those wastes that are generated in the filtration of cooling and washing water and contain fibers and a high concentration of binder and its components. To date, all of this waste has usually been stored in abandoned quarries.

This practice is likely to be banned due to pollution.

The invention provides a method for converting these wastes into non-contaminated substances. The method comprises treating the waste after heat treatment with heat so that the pollutants are incinerated to an uncontaminated substance such as CCl 2 and H 2 O.

Figure 9 shows an apparatus with which this method can be performed.

The waste 56 from the heat treatment stations and the water filtration station is transported by a conveyor 57 and delivered to a mixer 88 where it is mixed with discarded bonded fiber products 87 generated on the production line.

Upon leaving the mixer 88, the mixture is discharged to the incinerator 90 by a conveyor 89. The heat generated by the burner 91 raises the temperature of the waste above 1000 ° C. At this temperature, the binder and binder components are converted to uncontaminated substances such as CO 2 and CO 2 and released into the atmosphere with the combustion gases of the burner 91 through the chimney 93. The material, which consists of heat-melted fibers, collects at the bottom of the furnace 90 and is removed therefrom through a drain hole as early as 5 8114 92 in the form of a whisk and is cooled in a basin 94 containing water.

Figure 10 shows another device with which waste can be treated.

The mixture of wastes 56 and 87 from the mixer 88 is deposited by a conveyor 89 on a belt 94 passing through the furnace 95. With the heat released from the radiant burners or electric resistors 96, the furnace raises the waste to a temperature of the order of 600-700 ° C. At this temperature, the binder or binder components contained in the waste are converted to uncontaminated substances such as CCl 4 and IVO and removed through the chimney 97. The fibers that make up the majority of the waste soften under the influence of heat, regroup, and bind by sintering into slabs 98 with a volume much smaller than the initial volume of the waste. These tiles can then be returned to the fiber fabrication cycle.

Another important feature of the invention is the reduction of noise caused by the plants subject to the invention.

The main source of noise in these plants is the defibering device, more precisely the jets of medium leaving it at high speed. The volume of sound around the defibering device, where machine operators have to do their work, usually exceeds 100 decibels. In the open plants according to Figure 1, the shape of the zone surrounding the sound source is such that the sound source cannot be effectively isolated from the outside, since a relatively large free space must be provided for the passage of the absorbed air. In the plants of the invention shown in Figures 3 and 4, the wall of the barrier plate 32 having the nozzle 33i through which the fiber and gas flow 12 passes into the chamber 22 and its other walls 21 are shaped so that absorbent acoustic plates 99 and the chamber 22 can be mounted inside the chamber 22. 22 exterior insulating acoustic panels 100.

By installing these plates in the zone surrounding the fiber manufacturing apparatus 11, the sound level is reduced by 20-30 decibels, which considerably improves the working conditions of the machine operators.

The second sound source is the exhaust fan 19 · The sound power generated by this 3i 5 8114 is transferred down the connecting lines to the chimney, which, located outside the buildings protecting the plant, radiates the sound power to the environment.

In the plants of Figure 1, the large amount of gases discharged through the chimney 35 and the tendency to limit pressure losses in the chimney have led to the installation of a large cross-section chimney immediately on the exhaust side of the fan 19 and thus almost completely radiate the fan power to the environment.

In the plants according to the invention, shown in Figures 3 and 4, the small number of exhaust gases makes it possible to locate the exhaust outlet further away from the fan 19. It is located in the recirculation line 3, at least one bend of the fan 9 and at such a long end that at least part of the fan 19 of the sound power generated by it is absorbed into the wire 34.

The volume reduction thus achieved in the zone surrounding the chimney 35 may be 10 decibels or more.

Figure 11 shows an apparatus combination according to the invention, comprising: - A defibering device 101 in which molten material 102 is fed into a high-speed rotating body having a number of holes in its circumference through which the material exits under centrifugal force. The resulting filaments are then exposed to a concentric, annular, high-velocity jet of hot gas directed generally downwards, which pulls the filaments into thin fibers.

- A fiber dispersing device formed by an oscillating flue 14 in the flow path of the fiber and gas stream 12 from the defibering device.

- A cooling device comprising atomizers 50 for injecting cooling water into the stream 12. This device is placed between the dispersing device 14 and the gluing device 13.

- A mattress forming device 15 with a perforated belt.

- A receiving chamber 22 in the shape of a parallelepiped and delimited at the bottom by a perforated belt 15, vertical walls 21 and 32 5 81 1 4 on the sides, a horizontal wall 32 at the top, located 200 mm below the defibering device 101 and having a circular nozzle 33 through which flow 12 passes. The holes of this nozzle are shaped to facilitate the entry of the stream 12 and to be parallel to its tangent. The vertical walls 21 delimit the mattress forming zone for the perforated belt 15.

- A box 16 placed under the perforated belt 15 in the mattress forming zone and in which a vacuum is maintained by means of a fan 19.

- Separation and washing chamber 17, located downstream of the box 16, with sprayers 45 for forming curtains of small water droplets in the passage of the exhaust gases 29.

- On the downstream side of the chamber 17, a cyclone-type water separator 18.

- A blower 19 which sucks all the gases following the fibers into and through the receiving member 15 and presses them into the line 34.

- A recycle line 34, the downstream end of which opens from an opening 36 in the upper part of the chamber 22 to the zone surrounding the fiber scattering device 14. Recycled gases in the order of 90-95% of the gases passing through the receiving member 15 are introduced into the chamber 22 through the hole 3o down the recirculation line 34.

- A line 35 located above the line 34 and removing 5-10% of the exhaust gases passing through the receiving member 15 to the combustion device 39. After passing through an incinerator where their temperature is raised above 600 ° C, these exhaust gases are released into the atmosphere.

- Absorbent plates 99 and insulating plates 100, placed on the walls 21 and 32 in a zone close to the defibering device 101.

- Well 103, which collects the washing and cooling waters containing the fibers and the binder and the binder components dissolved or suspended, coming from the openings 24 and 25 at the lowest points of the chamber 17 and the cyclone 18. · - Pump 104, which presses the water in the sewage into the filtration device 51 .

33 5 81 1 4 - Vibrating screen type filtration device 51 »which separates insoluble waste from washing water.

- A basin 52 under the filter 51, in which the filtered water is collected.

- A heat exchanger 105 in which the water collected in the basin 52 is circulated by a pump 53, whereby it cools, releasing the heat accumulated in contact with the exhaust gases 29 as it passes through the chambers 22 and 17 and the box 16.

- Cooling tower 106, where the cooling water of the heat exchanger 105 is circulated by a pump 107.

- A pump 55 which circulates water from the basin 52, forcing it into the gas stream cooling device 50, the exhaust gas condensing and washing device 45, the glue production station 108 and the water treatment base 109.

- A water treatment station 109 in which the pressure of the water to be treated is raised to 16 ata by a pump 77, after which it passes through a heat exchanger 83 where it heats up to about 80 ° C. After leaving the heat exchanger, the water to be treated passes to a mixer 78 where it comes into contact with a stream of steam, preferably superheated, causing its temperature to rise to 200 ° C, where it is maintained for 2-4 minutes in a reactor 82 located on the outlet side of the mixer 78. After leaving reactor 82, the treated water is cooled to 40-50 ° C, after which its pressure is reduced to atmospheric pressure by means of a pressure relief valve 86 and passed to a centrifuge 110 which separates from it the binder which has become insoluble during treatment. The treated water is led to the basin 52.

- A fresh water inlet pipe 111 which opens into the basin 52 and allows the amount of water in the plant to remain constant.

- Conveyors 57 and 112, which transport waste from filtration station 51, water treatment station 109 and production lines to waste treatment station 113.

- Waste treatment station 113, consisting of a furnace with gas radiating tubes or electric resistors, in which the temperature of the waste is raised to 600-700 ° C, for burning the binder and binder components and sintering the fibers into thin plates which can be returned to the fiber production cycle.

Fig. 12 shows another device combination according to the invention, comprising: - A defibering device in which molten material, namely molten glass, flows from crucible 114 in strands 115 which solidify before coming into contact with traction rollers 116 feeding fixed strands or rods to a fast hot gas jet 117, usually in the direction , which is substantially perpendicular to the gas jet. As a result, the ends of the rods heat up and soften so that the jet is able to pull them into fibers and carry them with them to the mattress forming member in the form of a fiber and gas stream 12.

- Cooling device with atomizers 50 for injecting cooling water into the stream 12.

- A gluing device 13 for injecting a binder into the stream 12, located downstream of the cooling device.

- A mattress forming member 15 with a perforated belt.

- A receiving chamber 22 in the shape of a parallelepiped and delimited at the bottom by a perforated belt 15, vertical walls 21 at the sides and a wall 32 at the top and a vertical wall 118 at the rear about 200 mm from the nozzle outlet 117 with a rectangular opening 33 through which the current 12 passes.

The edges of this opening are profiled to facilitate the entry of the current 12 and parallel to this tangent. The vertical walls 21 delimit the mattress forming zone for the routed belt 15.

- A vacuum box 16 located under the perforated belt 15 in the mattress forming zone.

- A washing chamber 17 located below the box 16 and having nozzles 47 which open below the surface of the water mass 48 and through which the exhaust gases 29 flow. The atomizers 45 supply washing water, which the overflow pipe 24 removes to the collector 26.

35 581 1 4 - On the downstream side of chamber 17, a cyclone-type water separator 18.

- A blower 19 which sucks all the gases passing through the fibers to the receiving member 15 and presses them into the horn 34.

- A recirculation horn 34, the downstream end of which opens into the chamber 22 through two holes in the vertical directions 21 on both sides of the defibering device to the zone at the defibering device. Recycled exhaust gases, which can amount to 95% of the amount of gases passed through the perforated belt 15, are introduced into the chamber 22 through these holes.

- A line 43 which opens into the chamber 22 in the zone at this downstream end and which, through the fan 44, removes the non-recycled part of the exhaust gases to the combustor 39 · - Absorbent plates 99 and insulating plates 100 placed on the walls 21, 32 and 118 in the zone at the defibering device.

- A well 103 which collects the washing and cooling waters containing the fibers and the binder and the binder components dissolved or suspended, coming from the openings 24 and 25 at the lowest points of the chamber 17 and the cyclone 18.

- Pump 104, which presses water from the well to the filtration device 51.

- Filtration device 51, of the vibrating screen type, which separates insoluble waste from washing water.

- A filter 52 arranged under the device 51, which collects the filtered water.

- A heat exchanger 105, in which the water in the basin 52 is circulated by a pump 53, whereby it cools, releasing the heat accumulated in contact with the discharge jacks 29 as it passes through the chambers 22 and 17.

- The newly described plant further comprises, as shown in the figure, a water treatment station and a waste treatment station, which are analogous to the stations described in connection with Fig. 11.

36 5 8114

Fig. 13 shows another device combination according to the invention, comprising: - A defibering device in which molten material flows from the front chamber 118 of the furnace through holes in one or more rows of pins 119 in the drive plate 119, forming a large number of fibers flowing into the drawing zone. between converging gas jets. The jet exit nozzles 120 are located very close to the glass fibers, and the jets flow downward, following a direction that is substantially parallel to the direction of movement of the glass fibers. Most often, the showers are high-vapor. The resulting fibers, drawing jets, and the surrounding medium sucked by them form a stream 12.

- Cooling device 50 for injecting cooling water into the stream 12.

- A gluing device 13 for injecting a binder into the stream 12.

- A fiber splitting device 14 consisting of two compressed air injectors for guiding the fibers in the desired direction.

The plant according to Fig. 13 is in other respects analogous to the plant according to Fig. 11.

Fig. 14 shows a further device combination according to the invention, comprising: - A defibering device in which the material in the form of melt and thread 121 is directed to the circumference of the high-speed rotating rotor 122 by fast jets leaving the nozzles 123. The rotating body 122 converts a portion of the material received into fibers by centrifugal force and throws another portion onto a second rotor 124, which by an analogous process converts a portion of the material received into fibers. The number of rotors such as 122 is usually limited to two or three.

From the nozzle ring 125 surrounding the rotors 122 and 124, jets of medium leave, even at high speeds, which act on the fibers formed, directing them to the receiving member. These showers are air or • high pressure steam.

37 5 8114

Generally, nozzles 125 are also used to spray the binder onto the fibers.

The fibers, the control jets and the surrounding medium sucked by them together form a stream 12.

- A cooling device 50 for injecting cooling water into the stream 12 located downstream of the nozzles 125, some of which are sprayed with a binder.

The plant according to Fig. 14 is in other respects analogous to the plant shown in Fig. 12.

Claims (6)

38 5 81 1 4 A method for removing contaminants from a process for making fibers from a thermoplastic material by gas jets by stretching to form a stream of stretchable gas and stretchable fibers in a forming zone having a perforated receiving device at the boundary of the forming zone through which said stream passes and through which a mattress, characterized in that water and a resinous fibrous binder are sprayed into the gas and fiber stream (12) in the formation zone, that the gas deflected downstream of the receiving device is recirculated from below the receiving device to and through the receiving zone and into the receiving device (15); and includes solids from the diverted gas, separating the solids from the separated water, and reusing the water purified from the solids in a stream of gas and fiber stream. in the formation zone. Method according to Claim 1, characterized in that the water reused for spraying is cooled. A method according to claim 1, characterized in that water and the aqueous resinous binder are sprayed separately into the gas and fiber stream (12) in the receiving chamber and that the water released from the solids is reused in both water and the aqueous binder jet. A method according to claim 1, characterized in that the reused water is cooled in the upstream direction of the jet. An apparatus for carrying out the method according to claims 1-4, comprising a forming zone for the flow of stretching gas and stretchable fibers, a suction chamber, and a perforated fiber receiving device separating the suction chamber from the forming zone, characterized by a device (13) for spraying a liquid binder compound in a stream (12) in the formation zone, a suction blower (19) connected to deflect the gas from the suction coaxium, a device (18) for separating the liquid, binder-containing components from the deflated 39 581 1 4 gas deflected from the suction chamber, a device (51) for separating solids, liquid binder-containing components, an apparatus (55) for recycling the liquid components and reusing them in the spray binder compound, and an apparatus (19) for recycling the gas discharged from the suction chamber to the forming zone and collecting the fibers; through the liquid device after the components containing the liquid binder have been separated. Device according to claim 5, characterized in that it comprises the recirculation of gases in a gas outlet (35, 43) in the flow path, located between the entrained liquid separating member (18) and the fiber receiving member (15).