FI59446C - PROCEDURE FOR THE FRAMEWORK OF FIBERSHIP MATERIAL - Google Patents

Description

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Hint · och refisterstyreltan 'Ameka »utttgd och uti. * Kriftun puMkonrf 30. On. 8l (32) (33) (31) Fjryduttjr ucuotkuu »I || W pdortwt 27 · 12.77 USSR (SU) 2560226 (71) Vsesojuznoe Nauchno-Proizvodstvennoe Obiedinenie Tselljulozno-Bumazhnoi Pronyshlennosti, Prospekt Lvradika 72) Vyacheslav Sergeevich Alexandrov, Leningrad, Alexandr Evgenievich Guschin, Leningrad, Rudolf Vasilievich Zavodov, Leningrad, Elena Ivanovna Zhukova, Leningrad, Alexandr Alexandrovich Ivanov, Leningrad, Tatyana Semenovna Fofanova, Leningrad, Evgeny Ivanovich Mikhailov, Pavel Mikhailovich Luzin, Leningrad, Igor Alexandrovich Sergeev, Leningrad, Lidia Antonovna Pankratova ,, Leningrad,

Vera Egorovna Krylova, Leningrad, Semen Anatolievich Leibenzon, Leningrad, ussr (su) (7 * 0 Oy Kolst'er Ab (5I +) Method and apparatus for the production of fibreboard material - iBrfarande och anordning for framställning av fiberskivmaterial and an apparatus for producing fibreboard materials.

The present invention is most preferably used in the pulp, paper, textile and building materials industries to make a variety of paper, board, non-woven fabric, felt and building board products.

In order to produce a fibrous sheet material, it is essential to achieve an even distribution of the fibrous material in the gas stream with a predetermined dispersion value in the air / fiber stream along the entire flow path.

The air / fiber stream must have a specific fluidity in order for the stream shape to be made flat, as well as the internal structure of the air / fiber stream to change to obtain a uniform fiber distribution throughout the stream.

The air / fiber flow dispersion value is assumed to be the ratio of the volume of individual fibers or small groups of fibers to the volume of a single fiber having a species length of 2 59446, the species length being that prevailing in the fiber length distribution.

A homogeneous fiber distribution in the air stream requires that the fiber concentration in each individual unit volume of the stream varies little or not at all.

The dispersion value of the air / fiber stream and the even distribution of the fiber throughout the stream determine the degree of structural uniformity of the resulting fibreboard material, while the amount of fiber in the air stream determines the amount of gas to be removed from the air / fiber mixture to form a fibrous web.

On the other hand, the dispersion value of the air / fiber suspension decreases due to the high mutual adhesion of the fibers, i.e. the grouping of separate fibers takes place. To reduce the likelihood of fibers collapsing due to turbulent forces developing in the moving air / fiber stream, the fiber content should be low. In general, the fiber content should be in the range of 5-30 g / m, depending on the properties of the material to be produced and the quality of the fiber.

In addition, the high fiber content of the air / fiber stream reduces the flowability of the stream, said fluidity being a mandatory necessity to change the external shape of the air / fiber stream, e.g., cylindrical shape for a flat network.

Thus, a low gas content in the gas / fiber stream is a prerequisite for forming the fibreboard material. Therefore, if the layer of fibrous material is formed at a high speed, e.g. for a flat network moving between 180 and 900 m / min, a considerable amount of gas must be transferred out of the gas / fiber mixture.

A flat network on which the fibers are arranged to form a layer of fibrous material has a high coefficient of resistance, 2Q-500 depending on the fiber quality and the thickness of the fibrous layer. Therefore, the removal of a large amount of gas per unit time required for high speed fiber bed fabrication results in increased electric power consumption.

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The force consumed to overcome the resistance can be reduced by a suitable increase in the active surface of the flat network. However, this leads to a controversial increase in hardware size, resulting in additional consumption on metal structures.

On the other hand, the force required to overcome the resistance provided by the network during the layer formation process as the gas is passed through the network and the fiber layer assembled thereon can be reduced by increasing the fiber content of the gas / fiber stream. In this case, the gas / fiber flow must be consumed before it is fed to the network to achieve a uniform distribution in the velocity field, a uniform fiber distribution over the entire flow volume, and an increase in the gas / fiber flow dispersion value, all this to achieve a homogeneous layer of fibrous material. uniform material in mechanical and physical properties.

A method for making a fibreboard material is known in the art (U.S. Patent 2,689,985). According to this method, the fibrous material is finally divided and introduced into an expanding gas stream, where it is converted by mechanical agitation, whereby a uniform velocity field distribution is achieved and the separation of large groups into small fibrous pieces takes place. The gas / fiber mixture is then assembled into a network to form a fiber layer thereon.

An apparatus for producing a fibrous sheet material for this method comprises a disc mill for separating the fibers, said mill being connected via a discharge tube to a mixer having sidewalls and front walls in different directions and a rotating roller arranged inside it, which roller is provided with teeth. The gas / fiber flow is changed by mechanical agitation caused by a rotating roller, resulting in a uniform fiber distribution throughout the volume of the gas / fiber flow. The gas / fiber stream is fed from the mixer to a flat network.

A suction box is installed below the network to remove gas from the gas / fiber stream that is fed to the network during the layer formation process.

The disadvantage of the above-mentioned method and the corresponding device is that, due to the precipitation of the fibers in the form of flakes caused by mechanical mixing, it only allows the fiber content to be changed as low as 5-10 g / m 2. Milloxn is used for oral V.

h 59446 gas / fiber flow with a higher fiber content, the even distribution of the fibers over the entire volume of the flow is disturbed.

In addition, the gas / fiber stream fed to the flat network has a low fiber content. This results in an increase in electrical power consumption to overcome the resistance that develops in a flat network during the fiber layer formation process when a large amount of gas is removed through the network and the fiber layer placed on it.

A gas / fiber stream with a higher fiber content can be fed to the network if changing the flow before it is fed to a flat network is achieved by multiple dispersal of the fibers in the gas stream.

Another method for producing a fibreboard material is known in the art. In this process, the fibrous material is ground and fed into an expanding gas stream. The resulting gas / fiber stream is subjected to multiple dispersions and then passed to a flat network to form a fiber layer thereon.

The apparatus for carrying out this process comprises a mixer with sidewalls in different directions, its inlet opening into a gas / fiber stream pipeline, while its outlet is connected to a rectangular upper chamber. A number of streamlined bearing-shaped pieces are arranged in the chamber, their planes being parallel to the side walls, the upper part of each piece being arranged inside the mixer.

When the gas / fiber stream impinges on the streamlined bodies, a multiple scattering effect occurs due to the flexible pushing of the fibers against the curved surfaces in the streamlined bodies, whereby the gas / fiber stream is evenly distributed along the edges in the rectangular chamber.

However, the above-mentioned method and apparatus for producing fibrous sheet material fails to change the gas / fiber flow having a fiber content greater than 5-15 g / m 2. If a gas / fiber stream with a higher fiber content is fed towards the streamlined bodies, the force of the distribution fields is insufficient to change the gas / fiber flow, i. the forces generated in the process are insufficient to mix a gas / fiber stream containing a large amount of fibers per unit volume. As a result, a uniform velocity field distribution in the modified gas / fiber flow is not achieved.

In addition, the fiber content in the stream fed to the flat network is still low, resulting in increased power consumption used to overcome resistance in the flat network during the fiber layer formation process, as a large amount of gas must be passed through the network and the fibrous layer deposited thereon.

The gas / fiber flow can be varied simultaneously using the multiple fiber scattering effect and the transverse pulsation with respect to the gas / fiber flow.

Yet another method of making a fibreboard material is known in the art. In this process, the fibers are dispersed in the gas stream as a gas / fiber stream. after which the gas / fiber stream is then flattened. The resulting flattened gas / fiber stream is converted by feeding it to the cylinder element.

The interaction of the flat gas / fiber stream with the cylinder causes a multiple fiber scattering effect due to the flexible repulsion of the solid pulp upon contact with the surface of the cylinder. Thus, shear of the solid pulp occurs, i. increase in the distribution constant.

The cylinder belonging to the device produces transverse pulsations in the gas / fiber stream flowing over the cylinder, thus providing a uniform distribution in the velocity field of the stream. The modified gas / fiber stream is then fed to a flat network to form a fiber layer thereon. The fibrous layer is then subjected to further processing to obtain a finished sheet material.

The apparatus for carrying out the above process for producing a fibreboard material comprises an elongate slit nozzle having perpendicular sidewalls and approaching front walls, said nozzle inlet being in communication with the fiber dispersing means to re-emit the gas / fiber in a gas / fiber stream in connection with the chamber.

Below the elongate nozzle along its entire length is a cylinder attached at its ends to the side walls of the chamber. A special grid, to eliminate the turbulence of the current, is placed in the current leaving the cylinder and extends over the cross-section of the chamber.

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The layer-forming process takes place in a flat mesh by means of a suction box located below the chamber.

A disadvantage of the described method and apparatus for producing fibrous board material is that this apparatus allows a gas / fiber stream to have a fiber content of only 10-30 g / m 3. Once the gas / fiber stream is applied to the cylinder, transverse pulsations are formed in the gas / fiber stream flowing behind the cylinder, the force of said pulsations gradually decreasing as the current moves away from the cylinder. Because a gas / fiber stream with a higher fiber content is fed to the cylinder, the force of the distribution fields and the force of the transverse pulsations are insufficient to change the current and provide a fibrous material that is uniform in structure.

None of the current converting devices can provide the desired degree of conversion to a high fiber content stream.

Thus, only a gas / fiber stream with a low fiber content can be fed to a flat network to produce a sheet material with a homogeneous structure. This results in increased power consumption as it has to remove a large amount of gas per unit time during the bed formation process.

It is a main object of the present invention to provide a method and apparatus for producing fibrous board material that changes the structure of a high fiber gas / fiber stream, provides a uniform fiber layer to a flat network, as well as increase production volume, reduce to reduce size and metal consumption.

In view of this main object, there is provided a method of producing a fibrous sheet material comprising dispersing fibers in a gas stream to provide a gas / fibrous stream, directing the gas / fibrous stream to a flat network, degassing the gas / fibrous stream through said network, part of the gas is removed from the gas / fiber stream before it is directed to a flat network so that the fiber concentration in the gas / fiber stream can rise between 1 and 7 59446 3 ...

20-500 g / m, said concentration being selected according to the quality and properties of the fibers and the transverse pulsations being damped in the gas / fiber flow during movement.

The gas / fiber flow is modified according to the method 3 presented so that its fiber content increases from 5.0 to 50 g / m to 20 to 500 g / m. This occurs due to the movement of the fibers relative to the gas, causing the fibers to converge in a regular manner, resulting in an increase in local fiber content. As a result, part of the gas emptied from the fibers can be removed separately from the part of the gas impregnated with the fibers.

By providing attenuation of the transverse pulsations in the gas / fiber stream during its movement, a sheet material of uniform structure is obtained, this being achieved by eliminating the local flocculation which occurs in the gas / fiber stream as its fiber content increases.

It is desirable to keep the amount of gas removed from the gas / fiber stream before it is fed into a flat network in the range of 20-90%.

It is also desirable to dampen transverse pulsations by shrinking the gas / fiber flow in a direction that is normal for the flow of current.

Shrinking the gas / fiber stream in a direction that is normal for the flow of the current involves a tortuous flow of the current and at the same time an even distribution of the velocity field profile. This contributes to a steady, regular increase in fiber content and a decrease in the cross-current component of the current turbulence.

In view of this main object, there is also provided an apparatus for carrying out a method for producing a fibreboard material comprising a groove nozzle having normal side walls such as converging front walls, said nozzle inlet being connected to devices for dispersing fibers in a network to form a fiber layer thereon and located below said chamber, and the suction box being arranged under a flat network in which, according to the invention the side walls of the groove nozzle are parallel to each other, means for removing part of the gas / fiber stream gas are arranged in the chamber 880446 are provided with branching pipes for the removal of gas, being mounted substantially at the top of the chamber.

The parallel arrangement of the side walls of the groove nozzle eliminates any significant elongation of the velocity field profile, i.e. provides an even distribution of the velocity field profile.

Due to the arrangement of devices for removing part of the gas / fiber stream from the gas located below the outlet of the groove nozzle, degassing is achieved through pipe branches located at the top of the chamber, increasing the fiber content of the stream while decreasing the consumption of used electricity during fiber formation.

According to one embodiment of the invention, the devices for removing part of the gas from the gas / fiber stream comprise a plurality of guides arranged parallel below each other and 3-20 mm apart to form a vertical row below one front wall of the slit nozzle and at an angle of 3.5-11 ° with respect to the axis of the groove nozzle, each of the guides being oblique to the axis of the slot nozzle, forming an angle of 10-35 ° in the direction of gas / fiber flow.

Devices for removing part of the gas from the gas / fiber stream, formed as a plurality of guides arranged parallel to each other to form a vertical row below a front wall of the slit nozzle, at an oblique position and at a certain angle to the slit nozzle axis, develop a resistance gas leaves the outlet of the slit nozzle, whereby part of the gas changes its original direction and is gradually removed as it passes the openings between the guides as the gas / fiber flow passes along the row of guides. Due to the gradual removal of gas between the guides, the fiber content of the stream increases, which affects the uniform distribution of the velocity field profile of the gas / fiber stream.

According to another embodiment of the invention, the devices for removing part of the gas from the gas / fiber stream comprise a plurality of guides arranged parallel below each other and 3-20 mm apart to form two vertical rows * located below one front wall of the slit nozzle and 3, At an angle of 5-11 ° to the groove nozzle axis, each of the guides being oblique to the slot nozzle axis, forming an angle of 10-35 ° in the gas / fiber flow direction, with the rows of one row in a mirror image position relative to the guides of the other row.

Such a device design in which part of the gas is removed from the gas / fiber stream, comprising guides placed parallel to each other to form two vertical rows, each of the rows below one front wall of the slit nozzle, makes it possible to double the size of the active zone through which the gas is removed. , while the production of the machine remains at the same level.

Due to the converging position of the guides, the shrinkage of the gas / fiber flow is achieved in a direction normal to the direction of its movement, whereby the transverse pulsations are partially damped.

It is recommended to make the guides in the form of blades.

Due to the shape of the blades of the guides, the gas / fiber flow is prevented from losing fibers when part of the gas is removed.

It is recommended to arrange the guides in each row to form at least two groups of blades and to set equal gaps between the guides in each group, with gaps greater between the upwardly directed guides than between the downstream guides.

Due to the formation of two groups of guides in each row, and with the guides in each group equidistant and the gaps between the upstream guides being greater than the gaps between the downward guides, removal of the gas portion without loss of fibers is ensured as the gas / fiber stream flows along the guides. .

The gap between the guides in the upwardly directed group should not be more than 20 mm, while the gap between the guides in the downwardly directed group should not be less than 3 mm.

The invention will now be described in more detail with reference to embodiments thereof 10 59446 shown in the accompanying drawings, in which: Figure 1 is a flow diagram showing a method of producing fibreboard material according to the present invention; Figure 2 is a schematic view of an apparatus utilizing a method of producing fibreboard material according to the invention; Figure 3 is the same as in Figure 2, longitudinal section; Figure 4 is an enlarged view of point A in Figure 2; Figure 5 is an enlarged view of point B in Figure 2; Figure 6 is an alternative form of apparatus using a method of producing a fibreboard material in accordance with the invention; Figure 7 is the same as shown in Figure 6, in perspective view; Figure 8 shows a second embodiment of an apparatus using the method of the present invention to produce a fibreboard material; Figure 9 is the same as Figure 8, in longitudinal section; Figure 10. shows another embodiment of the apparatus using the method of the present invention for making a fibreboard material.

The method for producing the fibrous sheet material is illustrated by the flow diagram shown in Fig. 1.

The fibrous material and gas are fed to the device 1 to disperse the fibers into the gas stream, thereby obtaining a gas / fibrous stream 2. The obtained gas / fibrous stream 2 is passed through the slit nozzle 3 to the chamber 4, the gas / fibrous stream 2 is shrunk in the chamber 4. When the gas / fiber stream is shrunk, the gas and fibers move in different directions due to the fact that the density of the fibrous material is 800 times higher than that of air. The fibers run along a path that coincides with the original path of the gas / fiber stream 2, while a portion of the gas, free of fibers, begins to move in the opposite direction to the original direction of the gas / fiber stream 2. Some of the gas removed causes an increase in the fiber content in the stream.

The flow path of the part of the gas which has changed direction is indicated by arrows "a".

The gas / fiber stream 2 is shrunk in a direction normal to its direction of movement, whereby the transverse pulsations produced in the gas / fiber stream are damped to a degree. Thus, uniformity of the velocity field profile of the fibrous material in the gas / fiber flow, as well as a small-scale turbulence structure, is achieved. This in turn ensures a high fiber content, and at the same time a uniform structure of the gas / fiber flow after it has passed the chamber H.

The gas / fiber stream 2 is passed from the chamber H to the flat network 5, the rest of the gas being removed therefrom via a suction box 6 located below the flat network 5.

The direction of the gas part which is removed from the gas / fiber stream 2 when it is introduced into the flat network 5 is indicated by arrows "c". The fiber layer laid on the flat network 5 is then subjected to a special treatment to obtain a finished fibreboard material.

The part of the gas removed from the gas / fiber stream 2 in the chamber 4 and the part removed from the flat network 5 can be reused by introducing them into the device 1 to disperse the fibers without any further purification of the fibers from the gas, 3 as the fiber content in the gas is 0.02 - 0.5 g / m. These fibers can be reused just as well.

This has effectively solved the problem of environmental protection.

The proportion of gas removed from the gas / fiber stream 2 in chamber 4 is estimated to be 20-90%.

The amount of gas to be removed from the gas / fiber stream 2 is selected according to the desired mass of the finished material per square meter and the length of fiber fed to the dispersing device 1.

The amount of gas to be removed is estimated to be 20-40% in order to provide mobility for fibers with a length of 0.5-38 mm, in which case a fibrous board material with a high degree of structural uniformity with a mass of 12-40 g / m 2 must be obtained.

40-60% of the gas / fiber stream 2 must be degassed in order to allow less mobility of the fibers, with a fiber content of 0.5-38 mm, and when a fibrous board material of 40-100 g / m 2 must be formed.

60-90% of the gas must be removed from the gas / fiber stream 2 in the event that the mobility of the fibers is even lower in the gas / fiber stream 2, this being allowed for the production of a homogeneous fibrous sheet material with a mass greater than 100 g / m 2.

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If the amount of gas to be removed is less than 20%, the process does not justify the consumption of electric power, which increases drastically due to the considerable volume of gas that must be removed per unit time.

It is essentially impossible to remove more than 90% of the gas from the gas / fiber stream 2.

The device according to the method of producing the fibrous sheet material comprises a pipe 8 (Fig. 2) connecting a device 1 which disperses the fibers into the gas stream and an inlet opening of the slit nozzle 3. The slit nozzle 3 has parallel side walls 9, 10 (Fig. 3), which are normal for the adjacent side walls 11, 12. The outlet opening of the slit nozzle 3 communicates with the chamber 4.

Guides, represented by blades 13, are mounted in the chamber 4 below the front wall 11 (Figure 1). The blades are spaced apart parallel to each other, their spacing varies, and is 20 to 3 mm.

The gap 14 between the blades 13 is selected according to the fiber length used in the layer forming process. If the fiber length is 2 mm and less, the gap 14 is selected to be 10-3 mm, for the fiber length 20-35 mm the gap 14 is in the range of 10-20 mm. The blades 13 are in a stacked position and at an acute angle © (.in relation to the axis of the slit nozzle 3, in the direction of current movement.

The angle o (selected according to the mass of the fibrous material and the elasticity of the fibers. In case the fibers have sufficient elasticity and the mass of the fibrous material is sufficient, considerable inertia forces develop in the gas / fiber stream 2 as it moves along the blades 13. as it passes between the blades 13, the angle kul is set close to 35 °. As a result, the fibers protrude against the blade surfaces towards the axis of the chamber 4. In addition, such an angle provides additional resistance to the gas / fiber flow 2 by the blades 13. the gas is removed from the gas / fiber stream 2.

In the case where the elasticity and mass of the fibers are low, resulting in lower inertia forces in the gas / fiber stream 2 as it travels along the blades 13, the angle is set close to 10 ° to provide soft motion for fibers that do not have sufficient elasticity to be pushed from the blade surfaces along the blades. 13. In addition, such an angle ^ provides negligible additional resistance from the blades to the gas / fiber stream 2, which eliminates fiber loss upon degassing.

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The blades 13 are fixed at their end faces to the side walls 9, 10 of the chamber U (Fig. 3), the length of each blade being equal to the distance between the side walls 9, 10 of the chamber <4.

The blades 13 were in a vertical row oblique to the axis of the slit nozzle 3 at an angle β (Fig. 5) selected from the range of 3.5-11 °.

The maximum angle /}> is set if a steep blade resistance build-up is required in the gas / fiber stream 2 to enhance gas removal. High-efficiency degassing of the gas / fiber stream 2 can only be carried out if the mass of each base fiber is considerable, for example when using fibers with a considerable length or density (asbestos). In this case, the inertial forces acting on the fiber in the gas / fiber stream 2 are large, whereby the fiber loss with the gas to be removed is negligible.

Placing a row of blades at an angle greater than 11 ° causes unnecessarily intensive degassing, resulting in significant fiber loss during degassing.

If the fibers are short or have a low density, such as hollow fibers, the inertial forces acting on them are insignificant. In this case, vigorous degassing is not allowed, otherwise a large amount of fibrous material will be lost.

Therefore, the degassing process must be performed at a lower intensity, i.e. a low resistance to gas / fiber flow must be achieved. 2. The need to satisfy such requirements dictates that the angle ^ must be close to 3.5 °.

Connected to the upper part of the chamber M · (Fig. 2) is a branch pipe 15. A flat net 5 can be found under the chamber 4. The suction box 6 is placed below the flat net 5. The fibrous layer formed on the flat network 5 is then fed to a device 7 where it is subjected to post-treatment to obtain a finished sheet material.

Figures 6,7 show another embodiment of an apparatus for producing a fibrous material having means for removing part of the gas from the gas / fiber stream 2, consisting of a plurality of blades 13 forming two vertical rows, each row below one of the front walls 11, 12 of the slit nozzle 3 and in an oblique position relative to the axis of the slit nozzle 3, forming an angle of 3.5-11 °. The blades 13, which form a row located below the front wall 11, are arranged in a mirror image with respect to the blades 13, 14 59446 which form a row located below the front wall 12 of the slit nozzle 3. The blades 13 in each row are placed parallel below each other and 3-20 mm apart, each blade 13 being oblique to the axis of the slit nozzle 3, at an angle of 10-35 ° to the direction of current movement.

Figures 8,9 show another embodiment of an apparatus for producing a fibreboard material, in which each row of blades 13 is divided into two parts I and II. Part I is set below Part II. The distance 14 between the blades 13 of Part I is 20-10 mm, while the distance 14 between the blades 13 of Part II is set to 10-3 mm.

Figure 10 shows another embodiment of an apparatus for producing a fibreboard material, in which the row of blades 13 is divided into four parts III, IV, V and VI. The spacing 14 of the blades 13 of Part III is set to 20-17 mm, the spacing 14 of the blades 13 of Part IB is set to 16-12 mm, the spacing 14 of the blades 13 of Part V is set to 11-6 mm and the same spacing in Part VI is set to 6-3 mm.

The following considerations were taken into account when setting the blade spacing in each section. When the gas / fiber stream enters the zone of Part I (Figure 3), the fiber content in the gas / fiber stream is low and the resistance of the fibrous material to the transverse flow of gas is also low during its removal. In addition, due to the high mobility of the fibers due to the low fiber content in Part I, the inertia of each fiber particle is more pronounced than in the later parts. As a result, more intensive degassing is ensured in the zone of Part I, and a large distance between the blades can be formed practically without any fiber loss. The fiber content of the gas / fiber stream 2 increases as it passes through the Part I zone and enters the Part II zone.

The resistance to the transverse gas flow increases in Part II due to the higher fiber content. The same reason causes low mobility of the fibers, said mobility occurring under the influence of inertial forces. Thus, the probability of fiber loss with the gas to be removed increases.

However, the distance between the blades 13 in Part II is small, so that the degassing rate is reduced and the fiber loss is reduced.

Thus, by varying the distance between the blades 13 in each section, the flow of gas is monitored along the entire length of the row of blades 13.

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The proposed apparatus for producing the fibreboard material operates as follows: The fibers are delivered to the apparatus 1 (Figure 6) to disperse the fibers into the gas stream. The obtained gas / fiber stream 2 is fed through a pipe 8 to the inlet of the slit nozzle 3. By using the approaching front walls 11, 12 and the parallel side walls 9,10 (Fig. 7), the cross-sectional area of the slit nozzle 3 decreases, whereby the velocity of the gas / fiber stream 2 increases as it leaves the slit nozzle 3. At the same time, the gas / fiber stream 2 is shrinked. uniform distribution of the velocity field.

Leaving the slit nozzle 3 (Fig. 6), the gas / fiber stream 2 encounters a resistance caused by the approaching rows of blades 13. As a result, a considerable amount of gas reverses its direction of movement, and after being guided into the gaps 14 between the blades 13, enters the chamber 4 and is then removed from the apparatus along the pipe branch and 15.

With the density of the fibers being much higher than in the air, the fibers continue to move perpendicularly between the converging rows of blades 13 under the influence of inertial forces. Some of the fibers contacting the surfaces of the blades strike these surfaces, and after being pushed away from them, due to the direction of the blades at an envelope angle relative to the axis of the slit nozzle 3, move towards the central part of the cavity formed by the converging rows of blades.

As the gas is gradually removed through the gaps between the blades 14, the fiber content in the gas / fiber stream 2 increases.

The converging position of the rows of blades 13, which causes the gas / fiber flow 2 to shrink, has an increasing effect on the degree of current uniformity.

The high fiber content in the gas / fiber stream 2 causes a reduction in fiber mobility.

Bypassing the gas / fiber flow 2 between the rows of blades 13, it is changed to meet the requirements needed to obtain a uniformly structured fibreboard material and is introduced into the mobile network 5.

When the gas / fiber stream 2 comes into contact with the flat network 5, the rest of the gas is removed by means of a suction box 6, whereby the fibers are assembled on the flat network 5 to form a uniform fibrous layer. The resulting layer is then fed to a device 7 where it is subjected to a treatment to produce a uniform fibreboard material.

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Example 1 o

Sheet material with a mass of 105 g / m must be made of asbestos fiber with a species length of 2.5 mm.

3 a) fiber content in the gas / fiber stream 50 g / m b) gas / fiber stream velocity 10 m / s c) gas / fiber stream turbulence intensity cross-flow component 20% d) air is used as the gas medium, e) the amount of gas removed is 80-90%,. 2 because 105 g / m of fibrous material must be obtained from short fibers.

The devices for removing part of the gas from the gas / fiber stream consist of a plurality of blades forming two vertical rows, each row being positioned below one front wall of the slit nozzle. Each blade is oblique with respect to the axis of the slot nozzle forming an angle of 10 °, and each row of blades is oblique with respect to the axis of the slot nozzle forming an angle of 11 °.

The aforementioned minimum blade skew angle and the maximum row skew angle with respect to the slot nozzle axis are selected to provide efficient degassing of the gas / fiber stream as the latter moves between the rows of blades.

Each row of blades is divided into four sections. The first four parts, viewed from the nozzle, are the same length. The length of the fourth part is 1.2 times the length of the first part. The gap between the blades of the first part is 12 mm, the gap between the blades of the second part is 8 mm, the gap between the blades of the third part is 6 mm and the gap between the blades of the fourth part is 3 mm.

Due to the use of four parts, each with a different large gap between the branches, a smooth removal of the gas from the gas / fiber stream is ensured. The loss of asbestos fiber, most of which is a small fraction, is insignificant. Although the fiber length is small, the mass of the asbestos fiber is large, therefore the gap between the blades in the first part can be set much larger than the fiber length.

In this case, large forces of inertia develop in the gas / fiber stream as it moves along the blades in the first part, these forces preventing fiber loss.

The gas fiber stream is introduced into the slit nozzle at a speed of 10 m / s. When leaving the nozzle, its speed increases up to 15 m / s due to the converging front walls. As the gas / fiber stream passes between the rows of blades, the gas is partially removed therefrom, 50% is removed in the first section, 30% in the second section, 15% in the third section and 5% in the fourth section. The total amount of gas partially removed from the gas / fiber stream is considered to be 100%. The gas removed from the gas / fiber stream is passed from the chamber through the pipe branches to a device where the fibers are dispersed into the gas stream. The total fiber loss does not exceed 10%.

As a result of the removal of 8090% of the gas, the

O

the concentration in the gas / fiber stream is increased to between 250-500 g / m, while the transverse pulsations characterized by the cross-current component of the turbulence intensity of the gas / fiber stream decrease to 5-8%, making it possible to achieve a homogeneous structure for the gas / fiber stream.

The gas / fiber stream moving at a speed of 15 m / s is further fed to a flat network moving at the same speed.

The remaining part of the gas, in an amount of 10-20%, is removed by means of a suction box, which forms a fibrous layer of 70 g / m 3 on a flat network. The fibrous layer is then impregnated with a 3% silicone emulsion to obtain a material,. 2 with a mass of 105 g / m, and rolling and drying to achieve a moisture content of 2%. The finished sheet material has high thermal and electrical insulation properties and can be advantageously used in the electrical accessories industry.

Example 2

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A board material with a mass of 110 g / m must be made from bleached sulphate pulp with a fiber length of 1.5 mm.

3 (a) fiber content in the gas / fiber stream 50 g / m (b) air containing 10% carbon dioxide in addition shall be used as the gas medium to prevent the explosion of the gas / fiber mixture due to static electricity charges; c) gas / fiber flow velocity 8 m / s d) gas / fiber flow turbulence intensity cross-flow component 25%

The amount of gas that must first be removed is 60-80%, as a material with a mass of 110 g / m must be obtained.

Devices for removing a portion of the gas from the gas / fiber stream are provided by the plurality of blades forming two vertical rows, each row being located below one front wall of the slit nozzle. Each blade is oblique with respect to the slot nozzle axis forming an angle of 10 °, and each row of blades is oblique with respect to the slot nozzle axis forming an angle of 3.5 °.

The aforementioned minimum obliques of each blade and row of blades relative to the axis of the slit nozzle have been selected to provide efficient removal of gas from the gas / fiber stream as the latter passes between the rows of blades.

Each row of blades is divided into three sections of equal length. The gap between the blades in the first part is 11 mm, the gap between the blades in the second part is 9 mm, and the gap between the blades in the third part is 4 mm.

Cellulose fibers have a smaller amount of small fraction than asbestos fibers, so it is sufficient to divide the rows of blades into only three parts and perform degassing less softly.

The gaps between the blades in each part ensure efficient gas removal without significant fiber loss.

The gas / fiber stream is introduced into the slit nozzle at a speed of 8 m / s. When leaving the slot nozzle, its speed increases to 10 m / s. As the gas / fiber stream passes between the rows of blades, it is partially degassed, 55% of the gas is removed in the first section, 30% of the gas is removed in the second section, and 7% of the gas is removed in the third section. The total amount of gas removed as part of the gas / fiber stream is taken to be 100%.

As a result of 60-80% removal from the gas, the fiber content in the gas / fiber stream rises to 125-250 g / m, while the transverse pulsations in the gas / fiber stream decrease to 4-6%, making it possible to obtain a uniform gas / fiber stream.

The gas / fiber stream moving at a speed of 10 m / s is further fed to a flat network running at the same speed. The remaining part of the gas, 20-40%, is removed by means of a suction box, whereby a layer of cellulose fibers having a mass of 90 g / m 3 is formed on a flat network. The fibrous layer is impregnated with a 3% solution of soldered corn starch to increase the mass of the material to 110 g / m 2, then the material is rolled and dried to obtain a wrapping paper.

i9 59446

Example 3 2

Fibrous material with a mass of 40 g / m must be made of viscose fibers with a fiber length of 8 mm.

a) fiber content in the gas / fiber stream 25 g / m ^ b) air is used as the gas medium c) gas / fiber stream velocity 6 m / s d) cross-flow component of the gas / fiber stream turbulence intensity 38%.

The amount of gas that must first be removed is between 50-60% because the viscose fibers are long and because 40 g / m of material must be obtained.

The devices for removing part of the gas from the gas / fiber stream consist of a plurality of blades forming two vertical rows, each row being positioned below one front wall of the slit nozzle. Each blade is inclined with respect to the axis of the slot nozzle, forming an angle of 15 °, with each row of blades oblique with respect to the axis of the slot nozzle, forming an angle of 7 °.

Because the viscose fibers do not have sufficient flexibility, a 15 ° tilt of the blades relative to the slot nozzle axis causes the fibers to slide smoothly along the blades, while a 7 ° tilt of the blade rows ensures degassing of a reasonable intensity from the gas / fiber flow.

Each row of blades is divided into two equal parts. The gap between the blades in the first part is 10 mm, the gap between the blades in the second part is 5 mm.

The gas / fiber stream is introduced into the slit nozzle at a speed of 6 m / s. When leaving the slit nozzle, its speed increases to 8 m / s. As the gas / fiber stream passes between the rows of blades, the gas is partially removed therefrom, 60% of the gas becoming removed in the first section, and 30% of the gas becoming removed in the second section. The total amount of gas that is first removed from the gas / fiber stream is taken to be 100%.

As a result of removing 50-6% of the gas from the gas, the fiber content in the gas / fiber stream increases from 25 g / m to 50-64 g / m, while the transverse pulsations of the gas / fiber stream decrease to 7% due to flow shrinkage, thus providing a uniform structure gas / fiber stream.

A gas / fiber stream moving at a speed of 8 m / s is fed 2o 5 94 4 6 to a flat network running at the same speed. The remaining part of the gas, 40-50%, is removed by means of a suction box, thus forming a layer of viscose fibers with a mass of 30 g / m, which is then impregnated with 15% of the yesi-polyvinyl acetate dispersion to increase the mass of the finished material to 40 g / m. The material is rolled and dried to produce non-woven oil filter material for large diesel engines.

Example 4 2

Sheet material with a mass of 20 g / m must be made of synthetic polyester fibers with a species length of 28 mm.

3 a) gas content of the gas / fiber stream 8 g / m b) ionized air is used as the gas medium; c) gas / fiber flow velocity 8 m / s d) gas / fiber flow turbulence intensity cross-flow component 35%.

The amount of gas first removed is 20-25%, it has to produce 2 fibreboard materials with a mass of 20 g / m.

The devices for removing a portion of the gas from the gas / fiber stream are made in a plurality of blades forming a single vertical row positioned below one front wall of the slit nozzle. The gap between the blades is 20 mm. Each blade is inclined with respect to the slot nozzle axis, forming an angle of 35 °, while the row of blades is inclined with respect to the slot nozzle axis, forming an angle of 3.5 °.

The aforementioned heeling angles for each blade and row of blades relative to the axis of the slit nozzle are selected to ensure the removal of a small amount of gas substantially without fiber loss.

The gas / fiber flow is directed to the slit nozzle at a speed of 7 m / s. When leaving the slit nozzle, its speed is as high as 10 m / s.

As the gas / fiber stream passes along the blades, 20% of the gas is removed from it. As a result of 20% removal from the gas, the fiber content in the gas / fiber stream increases from 16 g / m to 21 g / m. The cross-current component of the turbulence intensity decreases due to the shrinkage of the gas / fiber flow to 12%.

A gas / fiber stream moving at a speed of 15 m / s is fed into a flat network moving at the same speed. The remaining 21 59 A 4 6 of the gas, namely 80% of the gas, is removed from the gas / fiber stream by means of a suction box, thus forming a layer of synthetic fibers with a mass of 15 g / m 2. The layer is impregnated with a 5% polyvinyl alcohol solution to obtain a material having a mass of 20 g / m 3, which is then rolled and dried. The finished material is "long grain" paper that can be used in the Electrical Supplies industry.

Example 5 2

Board material with a mass of 500 g / m must be made of defibrated wood fiber particles.

(3a) the gas content of the gas / fiber stream is 50 g / m; b) gas / fiber flow velocity 8 m / s; (c) cross-flow component of turbulence intensity 32%; (d) air is used as the gas medium; (e) the amount of gas removed is 85 to 90%, 2 it must be made of fibrous material weighing more than 100 g / m.

The devices for removing part of the gas from the gas / fiber stream comprise a plurality of blades arranged to form two vertical rows each located below one front wall of the slit nozzle, each blade obliquely relative to the slit nozzle axis, forming an angle of 30 ° to the axis forming an angle of 11 °.

The above-mentioned maximum tilt angles for each blade and each row of blades with respect to the axis of the slit nozzle have been selected to provide efficient removal of gas from the gas / fiber stream as it passes between the blade rows.

The wood fiber particles used in the process have a high mass and considerable elasticity, therefore the inertial forces acting on the fibrous material are considerable.

For the same reason, the dimensions of the gaps between the blades are the same, 6 mm. The gas / fiber stream is fed into the slit nozzle at a speed of 8 m / s. When leaving the slit nozzle, the gas / fiber flow rate increases to 10 m / s.

As the flow of gas and wood fiber particles passes between the blade rows, some 85-90% of the gas is removed. As a result, the concentration of wood fiber particles is caused to increase 3. . .

le 334-500 g / m. The cross-current component 59446 22 of the turbulence intensity decreases to 7-10% due to the shrinkage of the gas and wood fiber particles.

The current is still routed to the flat network in a direction that is normal to that level.

The flat net moves at a speed of 0.8 m / s. The remainder of the gas, in an amount of 10-15%, is removed from the gas / fiber stream by means of a suction box, thus forming a layer of wood fiber particles 2 with a mass of 400 g / m 2. The resulting layer is impregnated with a phenolic resin solution to increase the weight of the finished material. . .

flow 500 g / m. The material is then cut into sheets with dimensions 2 of 3 x 3 m, which are subjected to a compression of 60 kg / cm for 20 min at 180 ° C.

The finished material is a building fiberboard that can be used in the building materials industry.

Example 6 2

Wool felt with a mass of 400 g / m must be made of fibers with a species length of 10 to 35 mm.

q a) Gas / fiber stream with a fiber content of 40 g / m.

b) gas / fiber flow velocity 6 m / s; (c) a turbulence intensity cross-flow component of 40%; (d) air is used as the gas medium; (e) 90% of the gas to be removed.

The devices for removing part of the gas comprise two rows of blades, each row being placed below one front wall of the slit nozzle. The blades in each row are oblique, forming an angle of 18 °, with each row oblique by 11 °.

The above-mentioned tilt angles of the elements have been chosen taking into account the mass of the base fibers and their resilience. Because the fibers are long and have a considerable mass, efficient degassing can be allowed. The elasticity of the fibers is very high, therefore the tilt angle of the blade is set to 18 °.

The gaps between the blades are the same size, 10 mm, because the mass of each fiber is sufficient to ensure, under the influence of inertial forces, the high velocity of the transverse flow of the gas to be removed.

The gas and wool fibers are fed to the slit nozzle at a speed of 7 m / s. When left, the slit nozzle current moves at a speed of 23 59446 la 8.5 m / s and is channeled between two rows of blades. As the current flows between the two rows of blades, 88-90% of the gas is removed.

3

The fiber content in the gas / fiber stream is increased to between 410-500 g / m. The degassed gas / fiber stream is fed into a flat network at a speed of 8.5 m / s at an angle of 120 ° to its plane. The flat net moves at a speed of 1.35 m / s, the remaining part of the gas is removed by means of a suction box.

As a result, a layer of fibrous material having a mass of 400 g / m 3 is formed on the net.

The resulting layer is rolled.

The finished material is a felt used in the textile and building materials industries.

Although specific embodiments of the invention have been shown and described in detail, various modifications thereof will be apparent to those skilled in the art, therefore, the invention is not intended to be limited to the published embodiments or details thereof, and may be departed from within the scope and spirit of the invention.

I>!

Claims (10)

A method of making a fibrous sheet material, comprising dispersing fibers in a gas stream to obtain a gas / fiber stream (2), feeding a gas / fiber stream (2) to a flat network (5), degassing a gas / fiber stream (2) through said flat network (5) to form a fiber layer and its subsequent treatment to obtain fibrous sheet material, characterized in that part of the gas is removed from the gas / fiber stream (2) before being fed to the flat network (5), to increase the fiber content in the gas / fiber stream (2) to between 20-500 g / m 2, said concentration being selected according to the quality and properties of the fiber, and that the transverse pulsations produced in the gas / fiber stream (2) during movement are damped. Method for producing fibrous board material according to Claim 1, characterized in that the amount of gas removed from the gas / fibrous stream (2) before it is fed to the flat network (5) is kept between 20 and 90%. 2. 59446 Claims. A method of manufacturing a fibrous sheet material according to claim 1, characterized in that the transverse pulsations are damped by shrinking the gas / fiber stream (2) in a direction normal to the path of current flow. Apparatus for carrying out the method according to claims 1, 2 and 3, comprising a slit nozzle (3) with side walls (9, 10) normal to adjacent front walls (11, 12), said nozzle inlet being connected to the devices (1) for dispersing fibers a gas stream, while its outlet is connected to the chamber (4), a flat network (5) adapted to form a fibrous layer thereon and located below said chamber (4), and a suction box (6) arranged in the flat network (5) characterized in that the side walls (9, 10) of the slit nozzle (3) are parallel to each other, means for removing part of the gas from the gas / fiber stream (2) are arranged in the chamber (4) below the outlet of the slit nozzle (3), and ) is provided with branch pipes (15) for removing gas, which are mounted substantially at the top of the chamber (4). Device according to claim 4, characterized in that the devices for removing a part of the gas from the gas / fiber stream (2) comprise a plurality of guide pieces arranged parallel below each other and 3 to 20 mm apart and to form a vertical row located below one of the front walls (11, 12) of the slit nozzle (3) and at an oblique angle (^) of 3.5 to 11 ° with respect to the axis of the slit nozzle (3), each guide being oblique to the slit nozzle (3) ) at an angle (CC) to the axis of 10 to 3 ° in the direction of gas / fiber flow. Device according to claim 4, characterized in that the devices for removing part of the gas from the gas / fiber stream (2) comprise a plurality of guide pieces arranged parallel below each other and 3 to 20 mm apart to form two vertical rows, each of which is placed under one front wall (11, 12) of the slit nozzle (3) and obliquely forming an angle (/ 3) between 3.5 and 11 ° with respect to the axis of the slit nozzle (3), each of said guides being oblique to the axis of the slit nozzle (3) at an angle (c ^ ·) between 10 and 35 ° in the direction of gas / fiber flow, while the guides of one row are in a mirror image position relative to the guides of the other row. Device according to Claims 5 and 6, characterized in that the guide pieces are made in the form of blades (or blades) (13). Device according to claims 5 and 6, characterized in that the guides of said row are arranged to form at least two parts (I, II) and to form similar gaps (14) between the guides of each group, the upward part of the gap (14) I) between the guides being larger than the gap (14) between the guides of the downwardly directed part (II). Device according to Claim 8, characterized in that the gap (14) between the guide pieces of the upwardly directed part (I) does not exceed 20 mm. Device according to Claim 8, characterized in that the gap (14) between the guide pieces of the downwardly directed part (II) is not less than 3 mm. 26 59446