IE41882B1

IE41882B1 - Improvements in the manufacture of fibres and fibrous mat products

Info

Publication number: IE41882B1
Application number: IE2065/74A
Authority: IE
Original assignee: Saint Gobain
Priority date: 1973-10-10
Filing date: 1974-10-04
Publication date: 1980-04-23
Also published as: HU175296B; IL45755A0; TR18256A; AR209427A1; NL7412646A; FI291274A; JPS5843339B2; SU843766A3; ZA746264B; AU7405974A; DK528274A; BE820942A; JPS5076328A; CH597287A5; CA1056568A; BR7408419A; NO770918L; FI58114B; CA1069645A; DK149647B

Abstract

1429580 Reducing pollution in making resin-fibre mats SAINT GOBAIN INDUSTRIES 3 Oct 1974 [10 Oct 1973] 42998/74 Heading D1R In the production of a bonded fibre mat 23 pollution is reduced by recycling waste products by repeated passage through the mat, washing the waste products, purifying part of the waste at each cycle and transferring part of the heat resulting from fibre formation to a fluid which is then cooled. Glass fibres are produced by introducing molten material 102 into a perforated rotor and drawn downwards by an annular array of high speed hot gas jets. Alternatively the fibres are extruded from spinneret (112, Fig. 13, not shown), by directing a molten glass net (121, Fig. 14, n.s.) upon high speed rotors (123, 124) or by the action of hot gas jets upon glass rods or filaments (115, Fig. 12, n.s.). The drawn fibres are sucked onto perforated belt 15 by blower 19, distribution being achieved by oscillating nozzle 14 or by air pair of compressed air nozzles (14, Fig. 13, n.s.). Binder is applied by jets 13, preferably as an aqueous solution or dispersion of phenol formaldehyde resin, urea-formaldehyde resin, oxidised linseed oil or bitumen. Cooling water is supplied by sprays 50 situated above or below binder sprays 13 and/or below perforated belt 15 to remove the heat produced by fibre formation. (Little or no atmospheric air is drawn in for cooling, c.f. the prior art, Fig. 1, n.s.). The gases drawn through mat 23 are washed by sprays 45, by bubbling through wales in jar (48, Fig. 12, n.s.) or by counter-current contact with thin films of water flowing over dividing walls (46, Fig. 4, n.s.). Heat is also removed. Chamber 16 below the perforated belt may increase in cross section to reduce the velocity of the gas and thus collect particles of solid waste. A cyclonic or electrostatic precipitator 18 proceeds blower 19. Most of the partly purified gas is returned by duct 34 to mat forming chamber 22 and again passes through mat 23. 5% to 10% of the gas is taken to burner 39 where remaining organic impurities are connected to carbon dioxide and water and released to the atmosphere. Duct 35 leading to burner 39 may be situated in chamber 22 (Fig. 4, n.s.). Noise is reduced by absorbing panels 99, 100. The washing water collects at sump 103 and is passed through vibratory mesh filter 51 to remove fibres and insoluble binder. The filtered water is cooled by circulation through heat exchanger 105. Cooled filtered water is supplied via pump 55 to cooling sprays 50, washing means 45 binder preparation 108 and water treatment station 109. As illustrated station 109 comprises a pump 77 which raises the pressure to 16 bar, a heat exchanger 83 which raises the pressure to 80‹C, a mixer 78 in which superheated steam raises the water to 200‹C and a reactor 82 in which the treated water is kept for 2 to 4 minutes. The treated water is cooled in the heat exchanger, decompressed, centrifuged at 110 to remove binder insolubilised by the heat and returned to tank 52. In other embodiments heat is applied to the interior of a treatment tank by steam or an immersed burner or electric arc. In other embodiments the dissolved binder is removed by flocculation or bacterial action. The solid waste removed by filter 51 and centrifuge 110 is heated to 600 to 700‹C to burn organic material and frit the fibres into low volume plates which are returned to the fibre production station, or heated to 1000‹C to melt the waste fibres.

Description

This invention concerns a process and apparatus for forming fibres and making a fibrous mat product. The invention . ' -relates in particular, t’o such a process and-apparatus’, the use of which will make possible suppression of the harmful effects of, and removal of at least the major proportion of, pollutants which are noxious due to tfieir toxicity, odour and, dust content and which ure contained in gaseous or liquid effluents from a.plant producing mineral fibre mat products, that is mineral fibre: in the form of mats, panels, bats, and so on. The invention is particularly though not exclusively concerned with mats of glass fibre bound by thermo-setting of thermoplastic binders, which produce in the finished mat rigid bonds between the fibres.

The binders commonly used are· phenolic ,resins or aminoplastiCs,' pure or modified, because these have advantages, in'the manufacture of fibrous agglomerated products. They are thermo-setting, soluble or emulsifying in water, they'adhere well to the fibres, and are relatively inexpensive. These binders as generally used are dissolved or dispersed in water to which other constituents have been added to form the binder which is sprayed-onto the fibres.

Under the effect of the heat to whichthey are exposed during the manufacturing process .these hludure ilboralo toxic volatile . ·, ’ elements with a bitter odour oven ill’very weak concentration, .for example phenol, formal, urea, and.ammonia as well as products arising from decomposition of organic material.

Other binders are used for some applications because of their low cost.. Some extracts of natural products, for example · linseed oil, become hardened by oxidation. Others are thermoplastic such as bitumen for example. In the course of the fibre binding operation, all are raised, at least in part, to a temperature which is' sufficient to cause separation of noxious volatile constituents. -z 41883 Thus as used herein binder means one or all of the binding products mentioned above, whether used in liquid form, dissolved or in suspension in water or other liquid, or as an emulsion.

The invention refers to that part of the plant for the manufacture of fibrous mat products which includes a fibre producing device or devices, and in which the following operations are also carried out:feeding the fibres to a reception device for formation of 10 the mat product; binding the fibres with a binder which contains pollutants; forming the mat product on the reception device, which is usually a perforated belt; cooling the fibres and the attenuating and guiding fluids, and also fluids induced by the latter; such cooling is normally by means of air; separating the fibres and the various fluids by drawing them through the mat product as it is being formed; and evacuating all constituents not retained by the fibre mat product.

Large quantities of gaseous fluids and water come into contact with the binder which contains the pollutants and are contaminated following a process of pollution which is common to the known methods for formation of fibre mat products and which will not be described.

Pollution of gaseous effluents takes place in the following way: The binder is projected into the stream formed by the fibres and fluids coming from the fibre producing device in the form of .30 clouds of fine droplets. Part of the binder is captured by the -341882 fibres, part settles on the surrounding parts of the fibre producing device, and part becomes waste in the form of fine droplets and vapour.

Thus, two sources of contamination co-exist, on the one 5 hand bubbles of binder and on the other, vapours from the binder.

The device for spraying and projecting the binder delivers particles or droplets of a wide range of sizes, and the finest droplets are not captured by the fibres but are carried in suspension by the stream of fluids through the mat product being formed.

The droplets deposited on the fibres are subject to the kinetic effect of the stream of fluids which passes through the mat product. A significant amount of the droplets is removed from the fibres, passes through the mat product and becomes suspended in the evacuated fluids.

The need to obtain homogeneous distribution of binder in the mat product makes it necessary to inject the binder in the stream of fibres and fluids in a zone near the fibre production device where the stream still has a well-defined geometric formation, but where its temperature may be sufficient for some of the binder, and at least its more volatile elements, to be evaporated. These polluting vapours mix with tho fluids and contaminate them.

In the text which follows the expression waste products means the effluents which pass through the fibrous mat product and are evacuated downstream of it, that is to say, the whole of the attenuating and guiding fluids, and the fluids induced by them, as well as pollutants in the form of droplets or vapour in suspension in the fluids.

The operations use large amounts of water and thus make considerable pollution inevitable. Water is used for diluting and carrying the binder when it isto be used in liquid form; for wailing ihe waste, which 41889 includes operating in such a way that a large amount of the pollutants in the waste in the form of droplets or of vapour may be captured by droplets of washing water, so that the pollutants in the waste are transferred to the water; and capturing and carrying within the apparatus fibres suspended in the waste; and for washing the various parts of the apparatus such as the perforated belt and waste containers, so that the binder and deposited fibres are removed therefrom.

During these operations the washing water becomes charged with binder ingredients, soluble and insoluble, or in the form of vapour, and the concentration of pollutants can be high.

The above description of contamination of waste products and water is based on measurements and observations oarried out in a production plant. It is given by way of information and other explanations may be advanced.

In all production plants for fibrous agglomerates, and irrespective of the method of producing the fibres, the process of pollution described above involves considerable quantities of effluent. In the various well-known processes using a fibre producing device in which glass is attenuated to fibres by high-energy gaseous jets or blast, the quantities of waste products evacuated to atmosphere are of the order of the values given below:g 100 Nm per kilo of fibres in the method described in U.S. Patent No. 2,133,236 (Slayter); g 300 Nm per kilo of fibres in the Aerocor method described in the U.S. Patent No. 2,489,243; and - 5 41882 Nm per kilo of fibres for the Supertel method described in French Patent No. 1,124,489.

Tims, for a large manufacturing plant, there is a loss of 500,000 to 1,000,000 NiiP/Il.

In the well known processes in which material is attenuated into fibres by mechanical force, for example, by a centrifuge, and in which a gas stream is used only to transport the fibres (normally in a generally horizontal direction)to a reception device on which the fibres are deposited to form a mat, the quantity of waste is 3 less but still very considerable; for example 30 Nm per kilo of fibres for the method described in U.S, Patent No, 2,577,431 which for a large manufacturing plant amounts to a loss of 300,000 to 400,000 NnP/h.

The quantities of polluted water are more or less the same I t for all these processes and a're of the order of 1,000 m^/h and more for a large manufacturing plant.

These vast quantities of polluted effluents have led the authorities firstly to limit the concentration of phenolic deposits in effluents ejected into the atmosphere, then to prohibit in some countries, all ejection of pollutants.

In addition, limitations regarding the odour or the level of the dust particle content of evacuated effluents are imposed in some countries.

Thus, plants for the production of fibrous mat products are equally pollutant in this way, as in addition to toxic products or noxious products, the plant ejects large quantities of water vapour of the order of 20 to 3θ tons per hour for a large plant, which thus emits from its chimneys thick smoke. -641882 Noise ie another nuisance created by such a plant. The noise is mainly emitted by two sources, the fibre production device or devices and the waste extraction fans.

In fact all fibre producing devices used in such a plant require high speed jets of fluid either for attenuation of material into fibres, or for guiding the fibres. The sound level of such vets increases considerably with their speed. The level may exceed 100 dB near the fibre producing device, which is just where operatives have to work. Such a sound level is much above that considered tolerable.

In addition the noise from the waste extraction fans is transmitted along connecting channels to an exterior chimney which in effect acts as an antenna and radiates the noise into the surrounding neighbourhood. The resulting nuisance has led authorities to forbid the operation of some plants.

The necessity of reducing or eliminating pollution, and at a sufficiently low cost so as not to influence too greatly the cost of the finished product, has become pressing; much work has been carried out and some solutions put into effect.

According to this invention there is provided a process for forming fibres and making a fibrous mat product wherein:part of the waste products (as hereinbefore defined) are re-cycled by repeated passage through the fibrous mat product; the major part of the heat resulting from fibre formation and retained by the waste products is transferred to a fluid which is then cooled; the waste products are washed by a washing medium after passage through the fibrous mat product, so as to transfer some of the waste products to the washing medium; and -741882 the non-recycled gaseous waste products are purified and the purified products evacuated from apparatus in which the process is carried out.

Also accord Lug Lo Lb is .invention npparnLiis for producing Fibres and making a fibrous inal product, comprises:- a device for forming fibres; a chamber for surrounding the fibres between the forming device and a device for making a fibrous mat product and having an opening through which fibres and fluids from the fibre forming device can enter the chamber, the edges of which opening are arranged to be tangential to a stream of fibres and fluids entering the chamber; means for introducing recycled waste products into the chamber; means for introducing water and for causing it to contact the waste products; a device for separating water from the waste products; means for cooling the water, an extractor downstream of the device for making the mat product; a connecting duct between the extractor and the means for introducing recycled waste products into tho chamber, for the recycling of part of the waste products; and a duct for leading the non-recycled part of the waste products to a device for the treatment of the waste products before evacuation to atmosphere.

The invention may provide for recycling the greater part of the waste products and for treating and evacuating only a small part of them, the recycled part amounting to at least 955“ of the total quantity of waste normally evacuated to atmosphere. The quantity of waste to be purified before evacuation, of the purified products may thus be less than 55» °f the total, which permits use of a.relatively costly purification operation which is for example burning which is effective without involving a prohibitive expenditure of power. -841882 The washing medium (and also the cooling fluid) used in carrying out the process of the invention may conveniently be water and the invention may provide for making insoluble, thermosetting resins contained in the water. This may be achieved by a heat treatment at a temperature above 100°C and preferably between 150 and 24O°C. This heat treatment is preferably carried out under pressure. Application of this treatment for making insoluble dissolved binder ingredients enables them to bo extracted by known techniques, thereby maintaining the concentration of pollutants in the washing and cooling water at a level compatible with continuous re-use of the water in the apparatus. The washing water is thus circulated in closed circuit and evacuation of pollutants through this medium is avoided.

The invention will now be described by way of example, with reference to the drawings, in which :Figure 1 is a diagrammatic section of part of a plant for the production of fibrous mat products; Figure 2 shows part of Figure 1, modified by the addition of a housing around a reception chamber, which is extended to a fibre producing device; Figure is a diagrammatic section of one embodiment of apparatus in accordance with the invention; Figure 4 is a diagrammatic section of another embodiment; Figure 5 is a diagrammatic section of a washing chamber; Figure 6 is a graph showing the change in output after treatment for making effluent insoluble; Figure 7 is a diagrammatic section of a device for treating water by heating under pressure; -944883 Figure 8 Is a flingranmiatic section oi' a continuous process device Cor treatment oi' water; Figure 9 is a diagrammatic section of a device for thermal treatment of waste solids; Figure 10 is a diagrammatic section of another device for treatment of waste solids; Figure 11 is a diagrammatic section of a plant for manufacture of glass fibre mat; Figure 12 is a diagrammatic section of another plant for manufacture of glass fibre mat; Figure 13 is a diagrammatic section of another plant for manufacture of mineral fibres; and Figure 14 is a diagrammatic section of another plant for manufacture of mineral fibres from vitreous slag.

Referring to the drawings, Figuro 1 shows parts of a plant of known kind for the production of fibrous mat products, to which the invention may be applied. This device comprises :i) a fibre producing device 11 as commonly used for the manufacture of fibrous agglomerate mats in which material to be attenuated is subjected to the action of centrifugal or aerodynamic force, or to a combination of both. Aerodynamic force is applied to the material to be attentuated or to fibres with the aid of jets, generally at high temperature and high speed.

The fibres produced leave the device 11 dispersed in a current 12 of fluid which may be air in the form of high energy jets and fluids induced from the surrounding medium by them, which current 12 envelops the fibres and guides them in the form of a stream having fairly well-defined limits, towards a reception device 15 (see below). -1041882 ii) a binding zone, situated on the path of the stream of fibres and fluids, between the device 11 and the reception device 15 and in which sprayers 13 project the binder as a cloud of droplets onto the stream. A substantial proportion of the droplets intercept the fibres and cling to them, and the rest are in suspension in the gases accompanying the fibres, either in the form of droplets or in the form of vapour. iii) a device 14 for distribution of the fibres, situated in the path of the stream of fibres and gases, either between the device 11 and the binding zone, or (as shown in Figure 1) between the binding zone and the reception device 15. The device 14 imparts an oscillating movement to the stream or deforms it, so that the fibres are distributed over the reception device 15 so as to form a mat of generally uniform ratio of weight per unit surface area. iv) the reception device 15 is constituted by a continuous perforated belt on which the fibres are deposited to make up the mat. v) a chamber 16 below that area of the perforated belt where the fibres are deposited and in which reduced pressure created by an extractor fan 19 draws the gas accompanying the fibres from the device 11 to the belt 15 through the mat so that little or no gaseous fluid will be carried with the fibres out of the zone of mat formation. The fan passes the gas to a chimney 5· vi) a vertical frame 21, which extends from the belt 15 up to a level near the device 11 and which limits the formation zone of the mat so as to form a reception chamber or basket 22 encircling the stream of fibres and gas and which, as shown, is open at its upper part near the device 11, so as to provide a large opening 28. -114188S The speed of the attenuating and/or guiding jets or blast, generally above a hundred metres fber second, is much greater than the speed which the fibres and gas should have for correct formation of mat, when they arrive at the reception device, which speed should not exceed in general ten metres per second. It is necessary to slow up the jets or blast considerably. This is carried out by the transfer of the momentum of the jets to the fluid in which they flow, fluid which they induce and which they accelerate in their own direction of flow and with which they mix. It is this mixture of jets and induced fluid which constitutes the gas accompanying the fibres.

Since induction is progressive, the reduction in speed is not considerable until after a gaseous jet has passed through the surrounding fluid for a sufficient distance.

In the installation described above, to obtain at the reception device an arrival speed for the stream of fibres and gas of the order of ten metres per second, the length of the path of the stream from the device 11 to the reception device 15 is generally greater than 2 or 3 metres, and the quantity of fluid induced over this path length and which passes through the reception device 15 is at least equal to 10 or 20 times the quantity of fluid constituting the jets.

In the apparatus of Figure 1 all the fluid induced by the stream is formed by atmospheric air which enters the chamber 22 through the large opening 28.

Figure 2 shows a configuration of fluid flow inthe reception chamber of a modified apparatus, when-the surrourjdlng medium is not able to supply all of the fluids induced by the jets issuing from the device 11. - 12 41882 Figure 2 shows the device 11 from which the stream 12 of fibres and gas flows, binder spray nozzles 13, a device for distribution of the fibres 14, a reception device 15, and a reduced pressure chamber 16 in which waste products 29 flow after passage through the mat 23. These items are as in Figure 1. But in Figure 2 the walls 21 bounding the reception chamber22 are extended up to the device 11 so as to reduce considerably the opening 28 which connects the chamber 22 to atmosphere, thus reducing the quantity of air entering the chamber. Therefore, if in a section of the stream 12 (partially in the zones for example M and N adjacent the device 11, that is to say, close to the orifices which emit the jets for guiding or attenuating where the jet speed is highest) the surrounding medium will not be able to supply to the stream 12 the whole amount of the fluid which the stream could in fact induce; it will be the downstream zones, for example O and P, where the stream 12 is moving at reduced speed, which will supply the missing quantity.

Gas streams 30 emanating from the downstream zones Ο, P, will rise as shown along the walls 21 towards the upstream zones Μ, N which have the higher speed, will be entrained by the stream, and will be accelerated in the general direction of flow of the stream. Thus, zones of turbulence will be generated between the edge of the stream 12 and the walls 21. The intensity of the turbulence will increase with the quantity of fluid which the surrounding medium is unable to supply; their direction of circulation is such that the fibres which they tear out of the forming mat 23, and which they transport are directed along the walls 21 towards the distribution device 14, the nozzles 13, or the device 11. - 13 Thus, if the quantity of air entering the reception chamber 22 in Figures i and 2 is reduced to a value much lower than the quantity of air which the stream is able to induce, the intensity of the turbulence may be sufficient to cause deposition of fibres on the devices 13 and 14 and so disturb their proper function. The turbulence will also as explained disturb the mat 23 by lifting up fibres from it. This is known as inhibiting and it may be acceptable as long as the quantity of air entering the chamber 22 is not less than 60 or 70% of the necessary amount.

Below this value operation is not in practice possible.

If it is desired to reduce further, or suppress completely, the amount of air entering the chamber, the turbulence will be such that the fibres will be unable to come to rest on the reception device.

One feature of the invention is to reduce considerably or even eliminate tbe entry of atmospheric air into the chamber 22, whilst still preserving conditions suitable for formation of the mat Thus instead of using, as the induced fluid, atmospheric air, there is used part of tbe waste previously collected at the '0 outlet of the extraction fan, that is, to recycle part of the waste which continually passes through the chamber.

Referring now to Figure 5, the reception chamber 22 is closed at the top by a cover 32 which has an opening through which the stream 12 enters the chamber. The edges 33 defining tbis opening are tangential to the stream 12 and are shaped so that passage of the stream is facilitated.

For convenience in use the cover 32 may be at a distance II from the device li.

A washing chamber 17 is disposed downstream of the reduced pressure chamber 16, of a cross section generally greater than that of the chamber 16, and fitted with devices in which the waste products 29, that is, the gas accompanying the fibres between the device 11 and the reception device 15 and pollutants in suspension, are caused to contact a washing fluid, which may be water. In the washing chamber 17 the waste products are partly cleaned of the elements which they contain in suspension, which are mainly fibres and binder. On contact with the washing water the fibres in the waste capture droplets of water and as a result have a tendency to fall on to the bottom of the chamber 17, this phenomenon being accelerated by the sudden drop in speed of the waste following the increase in the cross section of flow from chamber 16 to chamber 17. A proportion of the droplets or the pollutant vapours is intercepted by the droplets of washing water and is dissolved by it. The combination Of these two operations forms the washing of the waste. The water, having served for washing, and to which at least part of the pollutants of the waste has been transferred, is evacuated through an outlet 24.

The plant also includes a separation system 18, of cyclonic or electrostatic type, disposed between the washing chamber 17 and the fan 19 and in which the waste is relieved of at least part of the droplets of water with which it has become loaded during the washing and which it is important to eliminate before entry into the fan 19. Washing water extracted from the waste is drained through an outlet 25.

A collector 26 leads the evacuated washing water via outlets 24 and 25 to the treatment zone. - 15 41882 The stream of fibres and gas passes the nozzles 13 and the distributin’ device 1¾. The fibres are deposited on the reception device 15 and the waste 29 passes through the mat 23 being formed, the chamber 16, the washing chamber 17, the device for separation of water 18, and is then passed by the fan 10 into a duet 54. I-'art of the waste is evacuated from the system through an outlet 35* The rest is re-cycled via the duct 54 to the reception chamber 22 through an opening 5b situated near the device ii. 1'· The quantity of gas entering the reception chamber through the opening 35 is equal to the sum of the quantity of gas issuing from the device ii and the quantity of air 27 induced during its passage of length H in the open air, less that quantity re-cycled through the duct 54. The quantity of gas entering the W chamber 22 increases therefore with length H.

In order that the system should remain in equilibrium, it is necessary that the quantity of waste gas evacuated from the system through the discharge outlet 35 should be substantially equal to the quantity of gas which enters in the system through the opening 33. The quantity of waste gas to be evacuated will thus decrease when the distance 11 decreases.

Other items seen in Figure 3 will be discussed below with reference to other Figures.

Figure 4 shows an embodiment, in which the distance H is nil, that is) in which the device li, or at least the opening for ejection of the attenuating and guiding jets, is in the chamber 22. The quantity of waste to be evacuated from the system will be more or less equal to the quantity of the fluids issuing from the device 11. - lb 41882 The proportion of waste re-cycled in this embodiment can reach values of 96 to 97?·· In the embodiments of Figures 3 and 4, where the quantity re-cycled corresponds to the quantity which can be induced by the device li, the flow of the fluids into the chamber 22 will take place universally in the direction of flow of the attenuating and guiding jets, in the absence of disturbing turbulence. The recycled waste follows more or less the lines of flow shown by 37.

One advantage of tbe invention is that it is possible, thanks to the fan 19, to impart to the re-cycled flow 37 a speed slightly higher than that of the induced air 27 in Figure i.

The flow 37 can thus have sufficient energy to prevent the inhibition of the fibres, as referred to above.

An advantage of the invention is that the quantity of waste evacuated can be as little as 3 to 4f/ of the quantity normally evacuated, so that it becomes feasible to apply to this small quantity of waste a purification treatment which is costly but effective.

Thus waste evacuated through the opening 33 can be burnt by raising the waste to ahove 600°C at which the pollutant of the waste, especially the phenolic ingredients are transformed by combustion into non-pollutants such as COg and water. This has in addition the advantage of destroying odour. Burning ls carried out in a device 3θ (Figure 3) having a combustion chamber 39, a burner 40 fed with a combustible mixture and a flame stabiliser 41. The treatment temperature can be between 300 and 400°C in the presence of a combustion catalyst. - 17 418 8 2 The purified effluent gas is evacuated to atmosphere by a duct 42. At the exit from the duct 42 the temperature of the effluent gas is sufficiently high, and due to recycling the loss is sufficiently low, that condensation of water vapour does not occur before dilution of the effluent in the atmosphere. Thus no thick smoke appears at the chimney.

Another advantage of the invention is that with the waste being partly recycled and partly subjected to full purification, it is not necessary to subject it to a preliminary thorough 10 washing, so that the size and cost of the washing device 17 and water separator 18 can be reduced.

In Figures 3 and 4 the reception chamber 22 encloses the nozzles 13 and the device 14 making them difficult of access. During operation it may be necessary to have access to the nozzles 13 or the device 14 and in so doing to open access ports in the walls of the chamber near the device 11. To avoid escape of recycled and not fully purified gas the pressure in the chamber 22 should be equal to atmospheric pressure or less than It by say one or two millimeters li^O. This also allows, when the 2υ access ports are closed, elimination of leaks caused by faults in sealing. The pressure in the chamber 22 is regulated to a required value by adjusting the reduced pressure in the chamber 16 by adjusting the fan 19, Figure 3.

Instead of evacuating a quantity of waste from the recycling duct 14, it can be evacuated directly from the chamber 22 via an opening 43 (1'igure 4) in the walls of the chamber in the zone where it is necessary to maintain the pressure at the required level. The waste is extracted by a small auxiliary - 18 41882 extractor fan 44 and a duct 35. The extractor 19 only recycles the waste. This arrangement allows more precise control of the zone of reduced or nil pressure.

Recycling causes the waste to carry out repeated frequent passages through the fibre mat and although the capture power of the mat may be low because the speed of the waste which passes through it is low, the number of successive passages is such (about 15 per minute) that a significant quantity of the binder in suspension in the waste, is retained by the mat. This allows a reduction of the quantity of binding material sprayed by the nozzles 13, which means an increase in the efficiency of the binding material of the order of 5$.

In the installation shown in Figure 1, it is necessary to maintain in the reception chamber 22 a predetermined temperature, and for this purpose to conduct away the heat introduced by the glass and the fluids. Since the binder is thermo-setting it undergoes continuous evolution which leads it progressively from the liquid state in which it is sprayed to the solid state. If the temperature in chamber 22 is excessive the binder may, during formation of the mat, reach a state sufficiently advanced to alter its capacity for binding the fibres. This is called pre-gelation, and it can be avoided by cooling the reception chamber 22.

In Figure 1, this cooling is carried out by the induced atmospheric air, which is generally at a lower temperature than the required temperature in the chamber 22. The quantities of heat brought into the chamber by the material and the fluids (and which are, according to the process for making the fibres, of the order of 1,500 to 15,000 Kcal, per kilo of material), are transmitted - 19 41882 by mixing with the induced air and by mixing with the waste, which gives a small amount of the heat to the washing water and evacuates the remainder to atmosphere.

In the embodiments of Figures 3 and 4, the small amount j of waste evacuated to atmosphere only eliminates a small amount of heat, and other means must be used to cool the chamber 22.

Thus some of the heat introduced into the chamber 22 is transferred to a heat-absorbing fluid, for example water, by contacting the stream of fibres and accompanying gas or waste in contact with this fluid. The latter is evacuated after it has absorbed the heat, and is then re-cooled. Exchange of heat between the stream of fibres and gas or waste and the cooling water, is made either by direct contact or through a heat-conducting wall which separates them. It is known that the quantity of heat exchanged 1ς per unit of time with this kind of transfer are proportional to the difference between the temperature of the fluid to be cooled and the cooling fluid, and to the size of the contact surface.

The relatively high speed of the gas or waste, having regard to the dimensions of the installation, means that the time available for the exchange of heat is short. In order to cool adequately it is therefore necessary that the amount of heat exchanged per unit of time should be great.

One method is to remove, outside the chamber 22, the introduced heat by cooling the waste In the chamber lfi and ln the washing chamber 17, where the space available permits the use of large contact surfaces between the waste and the cooling water. This large contact surface may be obtained hy dispersing the water in the form of fine droplets, by making it flow in the form of a very thin film, or by making the waste bubble through the water.

In Figure 3, for example, sprayers 45 project cooling water in the form of curtains of fine droplets, the curtains being more or less perpendicular to the direction of flow of the waste 29. The waste, having passed through the fibre mat being formed, enters the chamber i6 at a temperature of the order of 80 to 100°C and is cooled by contact with the curtains of water to a temperature of the order of 30°C. The temperature of the water at the entrance to the sprayers 45 is about 15 to 20°C according to the capacity of the cooling devices. In contact with the waste this water is warmed to a temperature of about 3θ to 40°C according to the output of the sprayers 45.

The part of the cooled waste which is recycled enters the reception chamber 22, where by mixing with the' gas from the device 11, cools the gas and the fibres, in the same way as the atmospheric air in Figure 1.

Another arrangement is shown in Figure 4 in which the 2(: water flows on dividing walls 46 in the form of thin films. The stream of waste 29 flows over these walls in contact with the films of water and is thus cooled.

Another arrangement is shown in Figure 5, where the stream of waste 29 is led to outlets 47 the surface of a body of water in a bath 48 downstream of the pressure-reduced chamber 16, so generating bubbles of gas of large water-to-waste contact surface, causing boiling of the body of water perpendicular to the outlets 47. ln other arrangements the introduced heat is removed outside tlie chamber 22 by direct cooling of the stream 12 of fibres and gas, by projection of water onto it in a zone where the contact surfaces cannot be large because of the limited space available, but where the difference between the temperature of the fluid to be cooled and the cooling fluid is great.

Thus in Figure 3, spray nozzles 49, disposed between the device 11 and the nozzles 13, project fine water droplets on to the gas and fibre stream to be cooled. The droplets reach the stream of gas and fibres in a zone where it is at a high temperature, perhaps 600°C, and are instantly vapourised. The considerable amount of heat, of the order of 650 to 700 Kcal per kg of water vapour, necessary for vapourisation of the droplets, is taken from the stream of fibres and gas which therefore undergoes rapid cooling so as to lower its temperature at the level of the nozzles 13 to about 100 to 120°C. The vapour produced is evacuated with tbe waste, through the mat 23 to the chamber 16 and the washing chamber 17 where, on contact with the curtains of water from the nozzles 45, it condenses and transfers its latent heat to the cooling water from the nozzles.

Location of the spraying device 49 between tbe device ii and the nozzles 13 is preferred since it has the following advantages.

Firstly, in this zone the difference in temperature between the stream to be cooled and the water is greatest and accordingly the transfer of heat can be greatest.

Then, spraying of the binder is carried out on to a stream of fibres and gas which has been cooled, at a temperature sufficiently low (100 - i20°C) for the reduction in quality of the binder by loss oi volatile elements to be limited or nil.

As a result efficiency of the binder is increased by about 5% and pollution of the waste is reduced accordingly.

Another arrangement is shown in Figure 4, in which the device 50, for projection of cooling water onto the stream of fibres and gas 12, is placed between the nozzles 13 and the reception device 15. As in Figure 3 the cooling water in the form of vapour passes through the mat 23. This water condenses by transferring its heat to the films of water flowing on the partitions 46. This water is evacuated through the outlets 24 and 25 at the low points of the chambers 16 and 17 and the separation device 18, to a device 51 in which solid particles in suspension, particularly fibres, are filtered out.

The device 51 may be a filter with meshes of vibratory or rotary type, or a separator, or a centrifuge.

The water without solid particles is collected in a container 52, whence it flows by gravity or by means of a pump 53, to a cooling station 54. At the outlet of this station cooled water may be evacuated to atmosphere or re-used in the system. Station 54 may be a cooling tower 106 in which the water is cooled on contact with air. But if the washing water is directly cooled in the tower 106, there is a risk of pollution by the more volatile pollutants remaining in the washing water. This risk is low, because the quantity of pollutants thus ejected into the atmosphere by the tower 106 is lower than 5? of the quantity ejected by the chimney 35 of an installation which does not recycle, such as that of Figure i.

In any event, to avoid this risk, the washing water may be cooled in an exchanger 105, the cooling liquid of which is - 23 44882 non-polluted water circulated in the cooling tower hy a pump 107.

Thus another feature of the invention is that there is no ejection of water outside the installation, so that the environment is not contaminated by pollutants in the water. In other words, the cooling water and washing water circulate in closed circuit.

In Figures 3, 4 and 5 the closed circuit is as follows. Water from the cooling station 54 is passed by a pump 55 (Figure 3) to the cooling nozzles 49 or 50 and to devices for condensation of steam and washing of waste in the chamber 17, and which comprise either sprayers 45 (Figure 3) or partitions 46 (figure 4) or again to the bath 48 (Figure 5)· The washing water and condensed steam with pollutants, fibres and binder ingredients, flow via the outlets 24 and 25 l5 and the collector 26 to the filtration device 51, which separates the washing water from the solids in suspension, fibres and insoluble binder ingredients.

These waste products are collected on a conveyor 57.

The filtered washing water containing only those pollutants 20 and binder ingredients which are dissolved, flows by gravity or by the pump 53 to the treatment station 54.

If the washing water is circulated in closed circuit, it is necessary to maintain the concentration of the dissolved matter or matter in suspension in the filtered water below a ••’5 certain level, of the order of 3 to 4# of units of the mass of dry matter per unit of mass of water. Above this level part of the matter dissolved or in suspension in the washing water, (mainly microfibres or microparticles of the binder not caught - 24 41882 by the filtration device 51, and tbe soluble ingredients of the binder) are deposited in various parts of the plant. The binder polymerises, forming viscous or rigid layers which progressively obstruct the outlets 45, 49 and 50 and the outlets of tbe reception device 15 for the passage of waste 29. There results a reduction in the quantity of the waste evacuated from the basket and in cooling of tiie waste, leading to early stoppage of the plant.

To maintain the concentration of matter in the water below a desired level, it is necessary to extract from the washing water considerable quantities of matter. A considerable proportion, of the order of 20 to 30% of the binder sprayed onto the fibres, is found in the washing water. For a large factory this leads to the introduction of 3,000 to 5,000 kilgrammes per day of binder (calculated in dry matter) into the closed circuit of circulation of washing water, and to maintain the concentration at an equilibrium value it is necessary to extract from the water a quantity of binder identical to that introduced.

Several methods of extraction are possible.

One method is to treat at least part of the washing water in a centrifuge which can separate smaller solid particles from the water than can the filter 51. The centrifuged water can return to the container 52 (Figure 3) or preferably be passed to the cooling nozzles 49· Another method is to treat the water by the addition of a flocculant, then to separate the flocculated matter.

The disadvantage of these two methods is that only Insoluble matter is generally extracted from the water. The - 25 41682 dissolved binder which constitutes the major part of the matter to be extracted is not affected, or only slightly.

Several methods of extraction of the dissolved binder are possible.

One method is to use the filtered or centrifuged washing water to dilute the binder during preparation of the binder to be sprayed onto the fibres. Introduction of the filtered or centrifuged water could be done at any point in the circuit downstream from the centrifuge 58, as by means of a valve 59 (Figure 3).

Another method is to use the washing water as a cooling fluid for the stream 12 of fibres and gas in the chamber 22.

The washing water is then projected against the stream 12 by the cooling device 49 (Figure 3) or 50 (Figure 4).

These two methods have the advantage that they allow part of the binder in the washing water to be re-used. Further they allow regulation of the quantity of binder sprayed by the nozzles 13 in relation to the quantity of binder that the mat 23 retains from the cooling water projected by the nozzles 49 or 50, which in (urn allows an improvement in the output of binder material, but these methods do not allow extraction from the washing water of a sufficient quantity of binder for the concentration in the water to be maintained below the desired level. For this reason the invention provides two methods which permit extraction of a considerable amount of the binder dissolved in the water circulating in closed circuit.

One method is to burn a small part, of the order of 1 to 5% of the output of the washing water in the closed circuit, in a device 60, Figure 4, which comprises a burner bi fed with a - 26 41882 combustible fuel-air mixture; a spray injector 62 to which the water to be treated is fed, by a pipe 63 and from which the water is projected under pressure in droplet form into the flame of the burner 61, under the effect of the jet 64 of air; a reaction chamber 65 in which treatment of the washing water takes place under the action of the heat given off hy the burner 61. This consists firstly in vapourising the washing water, and heating the steam and the binder ingredients to a temperature of 800°C, to convert the binder which is pollutant into non-pollutants such as C02 and water.

The non-pollutant vapour escapes through a chimney 66 to atmosphere at high temperature, thus avoiding formation of thick smoke.

The take-off point for the water to be treated is between the pump 53 and the cooling device 46, Figure 4.

This method has the advantage of extracting and transforming into non-pollutants all the ingredients of the binder in the treated washing water. Its disadvantage is that it requires a considerable supply of energy, and is thus costly. The effect of the cost of treatment on the price of manufactured fibrous products can be reduced by recapturing some of the heat of the steam in a high temperature heat exchanger producing superheated steam for various uses.

Another method is to heat a small part, of the order of i to 5/-, of the output of the washing water carrying dissolved binder in circulation in the circuit, so that the binder is made insoluble, then to separate it from the water by filtration, flocculation, or centrifuging.

If the water used for cooling and washing the waste - 27 41882 products contains after filtration dissolved binder or binder ingredients and is maintained at a given temperature for a given time, a proportion, which increases with temperature and time, of the dissolved binder is transformed into insoluble particles and is then in suspension in the water and can be easily separated out.

The proportion'of the dissolved matter made insoluble in the water by the treatment, characterises the output of the treatment. The temperature of the treatment has an important 10 influence on output; for example, it has been found that for water containing 1? of the ingredients of the dissolved binder the output of treatment was:- 41Λ if the water was maintained for 8 days at wσ0 40,. if the water was maintained for 3 days at 70 °C 40? if the water was maintained for 3 minutes at 16O°C 60? i i' the water was maintained for 3 minutes nt 180°C 95; if the water was maintained for 3 minutes at 240°C Figure 6 shows the percentage change in output as a function of temperature and treatment time. ln a large factory making fibrous agglomerate panels the quantity of water to be treated can amount to 50 mJ/h, so that it is necessary in order to avoid the installation of huge treatment devices to find the shortest possible time for treatment, and thus to work at a high temperature, say above 10u°C Thus another method is to treat the water in a pressure chamber at a temperature which is at about 5°C below the boiling point of the water at the pressure in the chamber, so that the water remains liquid. This has in addition the advantage that only a small amount of energy is required which, apart from losses, amounts to the heat required to raise the water temperature. Thus for the same extracted quantity of dissolved binder this method is four times less costly than the burning method.

One disadvantage met when water is heated in a container and the water contains, even in weak concentration, dissolved binder or binder ingredients, is that insoluble binder is deposited very quickly on the walls of the container to a thickness sufficient to obstruct the outlets of the container or the container itself.

If the heat necessary is given off within the body of the water to be treated and the walls of the container are kept at a temperature lower than tlie treated water, there is little or no deposit on the walls, since the insoluble binder remains in suspension in the water. This leads to heating of the water, either by mixing with hot fluids such as steam, preferably super-heated, or by combustion gas with an Immersed burner, or by means which localise energy in the mass of water, such as an electric arc.

A wide range of working conditions is possible, for example, 6 to 40 bars in absolute pressure, from 160 to 240°C in temperature, and 3 to 10 minutes in duration of treatment.

The following conditions provide an acceptable compromise between cost of power and cost of maintaining the equipment:Temperature 200°C Pressure 16 bars absolute Duration 5 minutes Output from 70 to 80% - 29 41882 This method can be carried out in either non-continuous or continuous operation. Figure 7 shows a device for noncontinuous operation. The water to be treated is introduced through a valve 67 into a chamber 68. Tiie quantity of water '3 introduced represent 70 to 80%· of the capacity of the chamber.

The heating fluid, preferably super-heated steam, enters the chamber from an injector 69, the outlet of which is immersed, as shown. The quantity of steam is adjusted by a valve 70 controlled by a regulator 71.

The treatment cycle is carried out in the following manner:Chamber 68 contains a charge of water to be treated at atmospheric pressure. Regulator 71 is set at the desired pressure, for example, 16 bars absolute. Valve 70 opens and the steam flows in through the ihjector 69, mixes with the water to he treated nnd in condensing transmits to the water all its latent and sensible heat. The temperature and pressure in chamber 68 increase to 200°C and 16 bars absolute. The introduction of steam is then stopped. The injector 60 has been set so that the rise in temperature and pressure is rapid, with a duration of less than one minute. The water is maintained at 200°C and i6 bars absolute for 2 to 4 minutes. At the end of this time, a pump 72 passes a further body of water to be treated, through a jacket 74 to a container 73. During its passage through the jacket, the water, at a temperature of about 40°C at the inlet, starts to cool the treated water in the chamber 68. The size of the jacket 74 is such that the water to be treated reaches the container 73 at about 80°C.

An additional cooling fluid circulates in a second jacket 75, - 50 41882 and completes the cooling of the treated water in the chamber 68. Cooling is complete when the temperature of the treated water falls below 100°C and preferably below 40 or 50°C. Then a valve 76 is progressively opened to decompress the chamber 68.

The treated water flows to a filtration station 51 or a flocculation device, or a separation or centrifuge device, which separates the now insoluble binder from the treated water. The filtered water flows into the container 52 and the extracted binder waste 56 is emptied onto a conveyor 57.

When the chamber 68 has been emptied, the valve 76 is closed and valve 67 is opened, and the pre-heated water now to be treated and contained in container 75, flows by gravity into the chamber 68. A drain 67a completes the installation.

Figure 8 shows a continuous processing system for water treatment.

A pump 77 passes at the required pressure the water to be treated to a mixer 78 in which an injector 79 opens and introduces the heating fluid, in this case steam. The steam mixes with the water to be treated and on condensing transfers all its heat to the water. The steam input is adjusted by a valve 80 controlled by a regulator 81, to maintain at the outlet of the mixer 78 the desired temperature for treatment. At the outlet from the mixer 78, in which the water has remained for about ten seconds, the water passes through a reactor 82 where the binder is made insoluble; the size of the reactor is such that the dwell-time of the water corresponds to the duration of the treatment time, that is, to 4 minutes.

At the outlet of the reactor, the water is cooled in an exchanger 83, to a temperature below 100°C and preferably to - 31 41883 to 50°C. Part of this cooling is carried out by water to be treated, which is thus preheated in the coil 84, from about 40°0 to about 8o°G. The other part of the cooling is carried out by cooling liquid circulating in a coil 85. it the nutlet of the exchanger 83 the treated water, now cooled, is reduced to atmospheric pressure by an escape valve 86 controlled by a regulator 87 set to the pressure in the plant. The water now flows to the filtration unit 51, or to a flocculation-separation device, or a centrifuge, which separates the binder made insoluble by treatment of the treated water. The filtered water flows to the container 52, and the waste product 56, the residue from the treatment, is emptied onto a conveyor 57.

The apparatus of Figure 8 allows more flexible and less costly operation than that of Figure 7.

Another method is to subject parts of the washing water containing pollutants to bacteriological treatment in an aerated tank. In such a tank bacteriological organisms, by enzyme attack destroy phenolic products, especially in water. The treatment, which corresponds to a total oxidation reaction, converts phenolic products into non-pollutant elements such as G0o and water. For this reaction to be complete it is necessary by aeration of tbe tank to supply the oxygen necessary to the bacteriological organisms and for the oxidation reaction.

In the manufacture of fibrous mat a large quantity of various waste products arise, but they all contain either binder or binder ingredients. - 32 41882 Firstly, there are faulty mats rejected on inspection.

These waste panels contain pollutants in dispersed form, but are voluminous. Then there are waste products from the filtration of the cooling and washing water, which contain fibres, and a high concentration of binder and binder ingredients. All these waste products were previously dumped, normally in disused quarries. This practice is likely to be forbidden, because it is pollutant.

The invention provides a method of transforming the waste products into non-pollutants. It consists in submitting the waste products, after preparation, to a heat treatment which transforms by burning the pollutants into non-pollutants such as CO,, and water. Figure 9 shows a device for carrying out such a method.

The waste products 56 are transported by the conveyor 57 and emptied into a grinder 88 where they are ground and mixed with rejected fibrous mat products 87 from the production line.

At the outlet of the grinder 88 the mixture is carried by a conveyor 89 to an incinerator 90 in which a burner 91 heats the waste products to a temperature above 1000°C. At this temperature the binder and binder ingredients are transformed into non-pollutants such as water and COg and exhausted to atmosphere with the combustion gas of the burner 91 through a chimney 93· The fibrous material, softened by heat, collects at the bottom of the incinerator 90 and is evacuated through a drain 92 in the form of a viscous stream and then cooled in a container 94 filled with water. The cooled material is then in the form cf granules which can be re-made into fibres.

Figure 10 shows another device for the treatment of the waste products.

The mixture ol' waste products 5b and b? from the grinder 88 is deposited by the conveyor S9 on a conveyor 94 which passes through an oven 95, where radiant or electrical resistance heaters 96 heat the waste products to between 600 and 700°C.

At this temperature the binder or binder ingredients are transformed into non-pollutants such as CO., and water which are exhausted through a chimney 97.

The fibres forming the major part of the waste products are softened by the heat, and collect and agglomerate hy fritting in the form of plates 98 with a volume which is much less than the initial volume of the waste products. These plates may then be returned into the circuit for fibre production. ln a fibre mat making plant the major source of noise is the device for the production of fibres, and particularly the high speed jets of fluid which are used. The noise level around such a device where the operatives have to work generally exceeds 100 decibels. However, an open plant as shown in Figure i does not allow efficient insulation of the noise source from the outside, because it is necessary to provide a large free space for the passage of the induced air·. In an installation as shown in Figure 3 there are provided on the walls 21 means for fitting internal and external acoustically absorbent panels 9‘> and 100 respectively. The reduction in noise level given b\ these panels Is, in the zone around the device li, of the older of 20 to 30 decibels, which is a considerable improvement.

Another source of noise is the waste extractor fan 19. This noise is transmitted by ducts to the chimney which, situated - 34 41882 outside the building housing the installation, radiates the noise to the neighbourhood.

In the installation shown in Figure 1, the large volume to be exhausted by the chimney 35, and the need to limit loss of power, has led to tbe installation of a chimney of large cross section, directly at the outlet of the fan 19, thus radiating virtually the whole of the sound emitted by the fan.

In installations as shown in Figures 3 and 4, the low volume of waste evacuated allows the fan 19 to be located some 10 distance from the exhaust for the waste. It is situated on the recycling duct 34 at a point which separates the fan 19 by at least one bend and a length of ducting sufficient for the absorption by the duct 34 of at least some of the sound emitted by the fan 19. fhe reduction in the noise level around the chimney 35 can be 10 decibels or more.

Figure 11 shows another plant in accordance with the invention, and comprising:a centrifuge 101 into which molten glass 102 is introduced 2° and from which the glass emerges in the form of filaments which are attenuated and driven downwards in well known manner by an annular gaseous blast; a device for distributing the fibres formed, in the form of an oscillating nozzle 14 which crosses the stream 12 of -6 fibres and gas from the device 101; a cooling device comprising nozzles 50 for projecting cooling water onto the stream 12. This device Is situated between the distributing device 14 and binder spray nozzles 13; - 35 41882 a perforated belt on which the mat 15 is formed; a reception chamber 22, parallelepiped in shape, hounded nt below hy the belt 15, laterally by vertical walls 21 and at the top by a horizontal partition 32 spaced 200 mm below the device 101 and including a circular opening 53 through which the stream 12 passes. The partition 32 around this opening is shaped to facilitate entry of the stream 12, and tangential to it. Vertical walls 21 bound the chamber 22; a chamber 16 below the belt 15 in the area of formation of the mat and having its’pressure reduced by a fan 19; an expansion and washing chamber 17, downstream of the chamber 16, and having sprayers 45, disposed so as to form curtains of water droplets in the path of the waste 29; downstream from the chamber 17, a cvclonic water separator 18; a fan 19 which forces all the gases to pass through the belt 15 and to compress them in the duct 34; the recycling duct 54 of which the downstream end opens through the opening 56 into the upper part of the chamber 22 at a zone around the device 14. The quantity of waste recycled, of the order of 90 to 95/ of that passing through the belt 15, is introduced into the chamber 22 through the opening 56 via the duct >4; a pipe 55 leading from the duct 54 to the burner 59, to evacuate from 5 to 10,5 of the waste which has passed through the belt 15. After passing through the burner where it is heated above 600°C, the waste is ejected to atmosphere; sound insulating panels 99 and 100 in the zone near the device 101; a trap 105 which collects cooling the washing water - 3b 41882 containing fibres, binder and binder ingredients, dissolved or in suspension, coming from outlets 24 and 25 of the chamber 17 and cyclone 18 respectively; a pump 104 which passes the water from the trap 103 to a filter 51 of vibratory mesh type, which separates the insoluble waste products from the washing water; a container 52 below the filter 51 to collect the filtered water; a heat exchanger 105 in which the water from the container 52 is circulated hy a pump 53, and is cooled to extract the heat gained from contact with the waete 29 during the latter's passage through the chambers 22, 17 and 16; a cooling tower 106, in which the cooling water from the heat exchanger 105 is circulated by a pump 107; a pump 55 which returns into circulation the water from the container 52 by pumping it to the nozzles 5θ for cooling the stream 12, to the condensation and washing device 45, to the binder preparation station 108, and to the water treatment station 109; the station 109, in which the water to he treated is raised to a pressure of 16 bars absolute by a pump 77 and is then passed through a heat exchanger 83 in which it is heated to 8o°C. At the outlet of this heat exchanger the water to be treated enters a mixer 78 where it is put in contact with a flow of super-heated steam, and raised to 200°C, at which temperature it is maintained for 2 to 4 minutes in a reactor 82 at the outlet of the mixer 78. At the outlet of the reactor 82, the treated water is cooled to 40 to 5θ°θ, then decompressed to atmospheric pressure in the expansion - 37 41883 chamber 86 and passed to a centrifuge 110 which separates the binder made insoluble liv the treatment. The treated water returns to coni al tier 52; an inlet 111 for fresh water lending into container 52, to maintain a constant quantity of water in the plant; conveyors 57 and 112 for removing waste solids from the filter 51 and water treatment station 109, and from the mat production line, to a station 113 for the treatment of waste products; and io the station 113 constituted hy an oven fitted with radiant gas heaters or electrical resistance tube heaters, in which oven the waste products are raised to 600 to 700°C so that binder and binder ingredients are burnt, and fibres fritted to form small plates which can he reintroduced into the system for the production of fibres.

Figure 12 shows another plant in accordance with the invention, comprising:a fibre production device in which a stream 115 of molten glass flows from a crucible 114 which solidifies before contact with transporting rollers 116, which introduce the solid filament or rod into a jet 117 of hot gas, normally in a direction perpendicular to the jet. The ends of the rods are heated and softened, so that the jet can draw them into fibres and carry the latter, in the form of a stream 12 of fibres and gas, to the mat forming belt; a cooling device comprising the nozzles 50 for spraying cooling water onto the stream 12; nozzles 13 for spraying binder on to the stream 12 downstream of the nozzles 50; a perforated belt 15 for formation of the mat; a reception chamber 22 of parallepiped shaped, bounded below hy the belt 15, laterally by vertical walls 21 and at the top by a partition 32 and at the back by a vertical partition 118 situated approximately 200 mm from the outlet of the jet 117 and including a rectangular opening 33 through which passes the stream 12. The edges around this opening are shaped to facilitate entry of the stream 12 and are tangential to it. The walls 21 bound the zone of mat formation; a chamber 16 with reduced pressure, situated below the belt 15, in the zone of formation of the mat; a washing chamber 17 below the chamber 16 and which includes outlets 47 below the surface of a body of water 48, and through which the waste 29 flows. Sprayers 45 introduce washing water whieh is discharged into collector 26 via an overflow 24; a cyclonic water separator 18 downstream of chamber 17; an extractor fan 19 which forces all the gas accompanying the fibres to pass through the belt 15 and passes it through the recycling duct 34; the duct 34, the downstream end of which opens into the chamber 22 hy wav of inlets (not shown) at the two vertical walls 21 situated on either side of the device for the production of fibres, in a zone situated near that device.

The quantity of recycled waste may he 95 of that passing through the belt 15, and is led into the chamber 22 through these inlets; a pipe 43 leading from the chamber 22 in a zone at the downstream end of the chamber, which evacuates a non-reeycled part of the waste through an extractor fan 44 to a burning off device 30; sound absorbent panels and insulating panels 99 and 100 on the partitions 21, 32 and 118 in the zone near the device for production of fibres; a trap 103 which collects washing and cooling water containing fibres and binder and hinder ingredients, dissolved or in suspension, coming from the openings 24 and 25; a pump 104 which pumps water from the trap to a filter; the filter 51, of vibratory mesh type, which separates insoluble waste products from the washing water; a container 52 below the filter 5i, which container collects the filtered water; and a hent exchanger 105 in which the water from the container 52 is circulated by a pump 53 and is cooled by giving up the heat from the waste 29 during its passage through chambers 22 and 17.

The installation which has .just been described includes in addition as shown stations for treatment of water and fo1 treatment of waste products analogous to those described above with reference to Figure 11.

Figure 13 shows another installation in accordance witli the invention and comprising a device for production of fibres in which molten glass flows from a furnace 118 through the openings of one or several rows of nozzles on a drawing plate 112, thus producing a large number of threads of material which flow into an attenuating zone where they pass between converging high speed jets of gas. Openings 120 for ejection of the jets are situated near to the threads of glass and the jets are directed downwards following a path which is virtually parallel to the direction of the movement of the glass threads.

Usually the jets are of high pressure gas. The fibres produced, the jets, and the surrounding induced fluid form the stream 12; cooling nozzles 5° for spraying cooling water onto the stream 12; nozzles 15 for spraying binder onto the stream 12; and a device 14 for distribution of fibres and formed by two compressed air nozzles for directing tbe fibres in the d-sired direction.

The installation shown in Figure 13 is analogous to that shown in Figure 11 in other respects.

Figure 14 shows another installation in accordance with the invention and comprising:a device for production of fibres in which a stream 121 of molten glass is directed onto the periphery of a rotor 122 turning at high speed by high speed jets issuing from nozzles 123. The rotor 122, under the action of centrifugal force, transforms into fibres part of the material which it receives and projects onto a second rotor 124 the rest of the glass, which rotor 124 similarly transforms into fibres the rest of the glass. The number of rotors like 122 is generally limited to two or three.

Through a series of openings 125 around the rotors 122 and 124 jets of fluid are emitted, also at high speed, which act on the fibres produced to direct them towards the reception device. These jets are formed by air or steam at high pressure.

Generally, openings 125 are also used for projection of binder onto the fibres.

The fibres, guidance jets and the surrounding induced fluid together form the stream i2.

Cooling nozzles 50 for spraying cooling water onto the stream 12, downstream from the openings 125 through some of which the hinder is sprayed.

The installation shown in Figure 14 is in other respects analogous to that shown in Figure 12.

Claims

1. CLAIMS:41882 1. A process for forming fibres and making a fibrous mat product where impart of the waste products (as hereinbefore defined) are 5 recycled by repeated passage through the fibrous mat product; the major part of the heat resulting from fibre formation and retained by the waste products is transferred to a fluid which is then cooled; 10 the waste products are washed by a washing medium after passage through the fibrous mat product, so as to transfer some of the waste products to the washing medium; and the non-recycled gaseous waste products are purified and the purified products evacuated from apparatus in which 15 the process is carried out.

2. A process according to claim 1, wherein the washing medium is water.

3. A process according to claim 1 or claim 2, wherein at least some washing medium is recycled. 20

4. A process according to any preceding claim, wherein the volume of purified gaseous waste products ejected to atmosphere is substantially equal to the volume of fluid used in the apparatus for attenuating material to fibres.

5. · A process according to claim 2, wherein the water is 25 ejected to atmosphere as steam or vapour.

6. A process according to any preceding claim, wherein the recycled waste products are returned into a fibre forming zone of the apparatus and are so guided as to follow between the zone and a zone of fibre reception, a path which is substantially parallel to that of the fluid used in attenuating -4330 material to fibres.

7. A process according tn any preceding claim, wherein a zone for ejection to atmosphere of non-recycled waste products is situated on the path of recycled waste, at a location such as to reduce noise transmitted to atmosphere by an extraction device for the waste products.

8. A process according to claim 2, wherein the washing water is heated to form steam which is then heated to between 500 and 800°C whcrehv pollutant components are transformed into nontO pollutant components.

9. A process according to claim 2, wherein the washing water is subjected to a bacteriological treatment process to transform pollutant components into non-pollutant components. 15

10. A process according to claim 2 for rendering insoluble anv thermo-setting resins contained in the water, wherein the water is heated to a temperature above 100°C.

11. A process according to claim 10, wherein the water is heated to between 150 and 240°C. 20

12. A process according to claim 10 or claim 11, wherein' the water is heated under pressure.

13. A process according to any of claims 10 to 12, wherein heat is imparted Internally to a mass of water.

14. Λ process according to any of claims 10 to 13, wherein 35 the water Is heated in a chamber maintained at a wall temperature lower than that of the water lieing heated.

15. Λ process according to anv of Claims 10 to 14, wherein the water is heated hy heat, given off by combustion gases from a burner immersed in the water. 44 41882

16. A process according to any of claims 10 to 14, wherein the water is heated by heat given off by an electric arc immersed in the water.

17. A process according to any of claims 10 to 14, wherein the water Is heated hy heat given off hy condensation of steam within the mass of water.

18. A process according to claim 17, wherein the steam is super-heated steam.

19. A process according to any of claims 10 to 18, wherein the water is filtered after heating to remove solids and insoluble constituents.

20. A process according to any of claims 10 to 18, wherein solids and insoluble constituents in the heated water are separated out by flocculation.

21. A process according to any of claims 10 to 18, wherein solids and insoluble constituents in the water are separated out by centrifugation.

22. A process according to any of claims 19 to 21, wherein insoluble constituents are burned In a furnace at a temperature of from 600 to 1000°C to render them non-pollutant.

23. A process according to any preceding claim, wherein the heat in the fluid used for attenuating material into fibres and the heat in the fibres is conveyed outside the apparatus by means of water.

24. A process according to claim 1, wherein water which is placed into contact with fibres and waste products to be cooled, is vapourised at least in part by heat removed from the fibres and waste products, and is removed mainly in the form of steam to a zone where it is condensed and cooled. - 45 - 41882

25. A process according to claim 23 or claim 24, wherein transfer of heat and pollutant from waste products to water is increased by use of a large contact surface between the waste products and the water. 5

26. A process according to claim 25, wherein the large contact surface is obtained by projecting fine water droplets into the waste products.

27. A process according to claim 25, wherein the large contact surface is obtained by causing the water to flow in contact with 10. The waste products in the form of a film.

28. A process according to claim 25, wherein the large contact surface is obtained by causing the waste products to bubble through the water.

29. A process according to claim 23 or claim 24, wherein heat 11. 15 is transferred from the waste products to water and the temperature of the water is increased hy spraying It into an upstream zone in which the waste products are at a higher temperature.

30. A process according to claim 29, wherein the water is sprayed as droplets into the waste products and onto fibres in 20 a zone situated between a zone of formation of the fibres and a zone of formation of a fibrous mat product.

31. A process according to claim 29, wherein the water is projected as droplets into the waste products and. onto fibres betiveen a zone of formation of the fibres and a zone of 25 projection of binder material.

32. A process according to any of claims 23 to 31, wherein the water includes the recycled water charged with dissolved constituents of a binder material for the fibres. - 46 41882

33. A process according to claim 32, wherein the quantity of binder material sprayed on to the fibres is reduced in accordance with the quantity of the said dissolved constituents in the washing water and retained by the fibrous mat product. 5

34. A process according to any of claims 23 to 28, wherein the water is projected onto the waste products after the latter have passed through a zone of formation of the fibrous mat product.

35. > A process according to any of claim 24 to 34, wherein the water is cooled in a chamber without contact with atmosphere. 10

36. A process according to claim 2, wherein part of the water is filtered and then used for preparation of a binder material for the fibres.

37. · A process according to any of claims 1 to 4, wherein the part of the waste products not recycled is heated to render 15 pollutant constituents non-pollutant by direct combustion or catalytic combustion.

38. A process according to any of claims 1 to 4, wherein the part of tho waste products not recycled is subjected to electrostatic purification. 12. 20

39. A process according to claim 1, wherein any solid waste products are treated hy heating to a temperature ahove 1000°C, so as to render mineral pollutant constituents non-pollutant, by melting and forming into bodies of reduced volume.

40. A process according to claim 1, wherein any solid waste 13. 25 products are heated to a temperature above 600°C, so as to render their pollutant constituents non-pollutant, the mineral produots of which they are composed being fritted into small bodies.

41. Apparatus for producing fibres and making a fibrous mat product, comprising:- a device for forming fibres; a chamber for 14. 30 surrounding the fibres between the forming device and a device -4741882 Tor making: a fibrous mat product and having an opening through which fibres and fluids from the fibre forming device can enter the chamber, the edges of which opening are arranged to be tangential to a stream of fibres and fluids entering the chamber? means for introducing recycled waste products into the chamber; means for introducing water and for causing it to contact the waste products; a device for separating water from the waste products; means for cooling the water; an extractor downstream of the device for making the mat product; a connecting duct between the extractor and the means for introducing recycled waste products into the chamber, for the recycling of part of the waste products; and a duct for leading the non-recycled part of the waste products to a device for the treatment of the waste products before evacuation to atmosphere.

42. Apparatus according to claim 41 , wherein water sprayers are situated between the fibre forming device and the device for making the mat product,

43. Apparatus according to claim 42, wherein the water sprayers are situated between the fibre forming device and a zone of projection of binder material.

44. Apparatus according to any of claims 4l to 43> wherein the water sprayers are downstream of the device for making the fibrous mat product.

45. Apparatus according to any of claims 41 to 44, wherein surfaces on which a film of water flows are situated in the path of the waste products.

46. Apparatus according to any of claims 41 to 44, wherein nozzles introduce the waste products below the surface of a bath of washing water situated downstream of the device for making the fibrous mat product. -4841882 47· Apparatus according td any of claims 41 to 46, including moans for treating at least part of the washing water for separation of pollutant constituents in the water. 48. Apparatus according to claim 47, including a filter, and a centrifuge or other separator for separating solid waste products from the washing water. 49. Apparatus according to claim 47, wherein the treating means is a thermal means. 50. Apparatus according to any of claims 41 to 49 including a boiler to heat the water under pressure to a temperature of over 100°C and a reactor in which resin in the water is rendered insolubi 0. 51. Apparatus according to claim 50, including a device for heating water under pressure by mixing with steam. 52. Apparatus according to claim 50, including a device for heating water under pressure by heat from an immersed electric arc 53· Apparatus according to claim 5θ, including a device for heating water under pressure by means of an immersed burner. 54. Apparatus according to any of claims 50 to 53, including a heat exchanger in which treated water gives up heat to water to be treated. 55· Apparatus according to claim 49, including a burner for evaporating the washing water and raising the water to a temperature of from 500 to 800°C. 56. Apparatus according to any of claims 41 to 55, including a heat exchanger for cooling the water. 57· Apparatus according to claim 56, wherein the heat exchanger is a cooling tower. -4941882 58. Apparatus according t'o any of claims 41 to 49 °r 55 to 57, wherein the device for the separation of water from waste products includes a shock chamber or an expansion chamber, or Is formed by a cyclone or an electrostatic filter. 5 59· Apparatus according to any of claims 4l to 49 or 55 to 58, wherein the opening in the chamber for surrounding the fibres and by which the fibres and entraining fluid enter the chamber, is at such a distance, in relation to the fibre forming device, that the length of the passage in free air of the jets issuing 10 from the fibre forming device is less than 200 mm. 60. Apparatus according to claim 59» wherein the shape of the chamber is such that the length of the passage in free air of the attenuating jets is fill, 61. Apparatus according to any of claims 41 to 49 or 55 to 60, 15 wherein the inlet to a pipe leading non-recycled waste products to the treatment device is situated at a point in the connecting duct between the extractor and the chamber surrounding the fibres. 62. Apparatus according to any of claims 41 to 49 or 55 to 61 , wherein the entrance to a chimney for evacuation to atmosphere 20 of recycled waste products is situated on the recycling duct at a point separated from the extractor and includes at least one bend, 63. Apparatus according any of claims 41 to 49 or 55 to 60, wherein the inlet of the duct leading off non-recycled waste products 25 to the treatment device is situated in a wall of the chamber surrounding the fibres, 64. Apparatus according to any of claims 4l to 49 or 55 to 63, having insulation for reducing noise emanating from the chamber surrounding the fibres. -5041882 65. A process for forming fibres and making a fibrous mat product, substantially as herein described with reference to Figures 3 to 14 of the accompanying drawings. 66. Apparatus for producing fibres and making a fibrous mat 5 produot constructed and arranged substantially as herein described and shown in Figure 3 to 14 of the accompanying drawings .