• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Removal of water from a fibre suspension, in particular cellulose pulp in a static thickner which essentially does not comprise moving parts. The clogging of the perforations in the screen sufaces (14,15,28,30,38,40,74,75,88,90) is reduced by dimensioning these perforations and the flow channels (13,33,37,76,87) in such a way that the pulp flows in the channels (13,33,37,76,87) as a plug flow, that is, the internal friction of the pulp is greater than the surface friction between the pulp and the screen surface (14,15,28,30,38,40,74,75,88,90). The process and apparatus (52,62) may be applied whenever a dilute pulp must be thickened, e.g. during pulp bleaching or refining of rejects.
    公开号:SU1732819A3
    申请号:SU874355036
    申请日:1987-12-16
    公开日:1992-05-07
    发明作者:Хенриксон Кай
    申请人:А.Альстрем Корпорейшн (Фирма)；
    IPC主号:
    专利说明:

    Fig.Z
    The invention relates to a technique for thickening fibrous suspensions and can be used in the pulp and paper industry.
    A known method of separating the liquid phase from the suspension and a device for its implementation is a tubular filter comprising several superposed layers of mesh plates, between which there is a material for separating the liquid phase from the suspension and fine filtration of the latter.
    This technical solution is designed to separate water and other liquid substances from the solid component, but it cannot be used to thicken the fibrous suspension, since the long fraction of the fibrous suspension will be collected in the mesh plates and the fine filter material between the plates. will be clogged with a fine fraction of the fiber suspension.
    There is also known a method for thickening a suspension consisting of a crumb and a liquid by separating the filtrate under the influence of a difference in pressure and a device for its implementation in the form of a tubular thickener. The walls of the thickener consist of ribs parallel to the suspension flow, between which there are gaps so small that solid particles do not penetrate into them. The diameter at the inlet of the thickener channel corresponds to the outer diameter of the thickener, therefore even those solid particles that have fallen into the gaps between the ribs are carried away by the flow, which eliminates clogging of the thickener.
    The disadvantage of this technical solution is the complexity of the thickening process, since the filtering surface of the thickener is formed by freely spaced rods, which requires extremely high accuracy and thoroughness of their manufacture and assembly when forming slots of equal flow area.
    Closest to the invention is a method of thickening a fibrous suspension by separating the filtrate under the influence of a pressure difference acting on the filtering surfaces, including feeding the fibrous suspension to the channel formed by the filtering surfaces, separating the filtrate when the suspension moves through the channel in the form of a piston flow, consisting of a multidimensional fiber mesh, and controlling the amount of filtrate withdrawn and the flow rate of the slurry through the channel by adjusting the pressure difference across the filter surface so that the internal friction of the slurry in the stream exceeds the flow friction surface and the filter surface and the apparatus thereof, comprising a thickening element having a slurry flow path bounded by filtration surfaces mounted in the thickening element
    0, the distribution element, bounding together with the walls of the condensing element, the cross-sectional area of the condensing element in such a way that the cross section of the suspension flow channel has a circular shape.
    The disadvantage of this technical solution is that the movement of the suspension in the thickening process is carried out with the stops necessary to bring
    The effect of the means of washing the filtering surfaces of the thickening element, substantially reflects on the effectiveness of the method being implemented.
    The aim of the invention is to increase the efficiency of the process.
    The goal is achieved by the fact that in the method of thickening a fibrous suspension by separating the filtrate under the influence of the pressure difference acting on the filtering surface, including the supply of the fibrous suspension to the channel formed by the filtering surfaces, the filtrate separates as the suspension moves through the channel a piston current consisting of a multidimensional fibrous mesh, and controlling the amount of filtrate discharged and the flow rate of the slurry through the channel by adjusting the pressure difference across the filter so that the internal friction in the flow exceeds the surface friction of the flow and the filtering surface, the filtrate is separated by continuously or stepwise decreasing the flow rate of the suspension in the direction of its movement through the channel, the filtrate can be separated in successive stages, one after the other, between which the suspension is homogenized, while on the surface
    0 sieves can direct high-frequency vibrations to reduce surface friction and eliminate fiber sticking to the sieve surface, and in an apparatus for carrying out the method comprising thickening
    5 element, having at least one flow channel of the suspension, bounded by filtering surfaces, installed in the thickening element, at least one distribution element, bounding together with the walls of the thickening element, the cross-sectional area of the thickening element so that The circular shape, the cross section of the flow channel is made variable, increasing in the direction of movement of the suspension, while the cross sectional area of the flow channel may stepwise or evenly, the thickening element may contain at least two successively distributed distribution elements, and the cross-sectional area of the first element in the direction of movement of the suspension is larger than that of the second, at least one of the filtering surfaces bounding the suspension flow channel conical and positioned so that the cross-sectional area of the channel increases in the direction of the slurry and at least one of the surfaces bounding the channel may be made flexible in the direction perpendicular to the flow of the suspension.
    Figure 1 presents a graph of the surface and internal friction of the suspension from its concentration; Fig. 2 is a diagram of the effect of perforation size of filtering surfaces on the behavior of fibers near the perforation; Fig. 3 shows a device for thickening a fiber suspension, a longitudinal section; Figures 4-6 are the same; 7 is a schematic of a device for bleaching fibers; Figure 8 is the same for recycling; Fig. 9 is a graph showing changes in the main parameters during the thickening process.
    The method of thickening the fibrous suspension by separating the filtrate under the influence of the pressure difference is carried out in a device comprising a condensing element 1, having a flow channel of the suspension 2 limited by filtering surfaces 3, installed in the condensing element 1 a distributing element 4, bounding together with the walls 3 of the condensing element 1 the cross-sectional area of the condensing element 1 in such a way that the cross section of the flow channel of the suspension 2 has a circular shape and is made variable, increasing in eg suspension of suspension. The suspension flow channel has an inlet 5 and outlet 6 of the aperture and is enclosed in the area of filtering surfaces 3 by a casing 7 with a filtrate outlet pipe 8 equipped with a control valve 9. The thickening element 1 may have at least one homogenization zone for the suspension 10 located between two thickening zones 11 and 12, which is structurally an abrupt change in cross section of the thickening element 1, and in order to avoid clogging the flow channel 2, at least one of the filter surfaces 3 is limited vayuschih flow channel 2 may be made flexible in a direction perpendicular to the flow
    0 suspension - such a surface passes the lumps and again takes the original position,
    The method is implemented as follows.
    5 The initial fiber suspension of a certain concentration is fed through the inlet 5 to the flow channel of the suspension 2, when moving along which it is separated from the suspension by a piston flow
    0 filtrate through surface 3 under the influence of pressure difference. The required pressure difference on the filter surfaces 3 is created either by the hydraulic pressure created by the suspension itself, by the pressure of the feed pump, by suction created separately, or by a combination of these methods. The thickened suspension is discharged from the device through the outlet 6, and the filtrate through
    0 nozzle 8,
    The movement of the suspension through the channel 2 by the piston flow, i.e. provided that the internal friction of the suspension in the flow exceeds the surface friction of the flow and
    5 of the filtering surface is ensured by the choice of the concentration of the initial suspension, its speed through channel 2 and the size of the perforation of the filtering surfaces 3.
    0 The origin of FIG. 1, where the abscissa axis characterizes the change in the concentration of the suspension, and the ordinate axis shows the friction, and where curves 1 and 3 illustrate the dependence of the friction flow of the suspension and the filtering surface,
    5, respectively, for coarse (up to 1 mm) and fine (about 0.2 mm) perforations, and curves 2 and 4, friction in the slurry flow, respectively, at high and low speeds of flow, to ensure the flow of the piston suspension concentration equal to coarse perforation or fine perforation, while surface friction 3 does not exceed internal friction 2. On the other hand, if the initial suspension concentration and required after condensation are known and if the effect of flow rate on friction is known, then the maximum perforations and the filter surfaces. When the required thickening is not achieved in a device with a specific perforation, the thickening is carried out in stages using distribution elements 4 in series with the thickening element 1, the cross-sectional area of which decreases in the direction of flow of the suspension, increasing its velocity those. a step change in the concentration of the slurry from Si to $ 2 is provided at an average of 5 H and from 3 H to S4, etc. (figure 4),
    In the process of thickening, the suspension may be subjected to homogenization in the corresponding zones 10, where mixing of the outer, more concentrated layers of the flow is carried out, with medium, less concentrated, in order to average the concentration of the suspension in the flow.
    Figure 7 shows the use of the invention for bleaching a suspension. A suspension of 12% of accumulator 13 is pumped by pump 14 through a thickener 15 into a chemical mixer 16, and the concentration of suspension by the time it reaches mixer 16 is about 18%. . The slurry is then taken to a bleaching apparatus 17.
    Another exemplary application of the invention is shown in FIG. 8 for waste processing. In this case, the suspension is pumped from the tank 18 for the suspended waste using a pump 19 to the mixer 20. From where the thickened from 3 to 8% concentration of the suspension is sent to the mill 21.
    The method and apparatus of the invention has many uses. Due to its simplicity of construction, small size and reliability of operation, the device can be used in many process streams where conventional drum thickeners are difficult to adapt to work. In the case of clogging of the filtering surfaces 3, it is possible to install a backwash device in the device or the inner element can be positioned so that it can be moved in the direction of flow. You can also install various scrapers or rotors in the thickener.
    Fig. 9 shows the dependence of the pressure difference on the filtering surface over time and the change in the volumetric flow rate of the filtrate in the nozzle 8. At the initial stage, when the device starts up, both the pressure difference on the filtering surface and the flow rate of the filtrate constantly increase, i.e. . internal friction of the piston flow of the fiber suspension
    more surface friction between the flow and the filtering surface, since the volume of the filtrate is constantly increasing with increasing pressure difference. However, at a certain pressure difference, the volume of the filtrate begins to decrease rapidly, and this means that fibrous meshes are quickly built on the filtering surface. This indicates that surface friction increased to a greater extent than internal friction in the slurry flow. At this stage, the pressure difference should be increased, as shown in FIG. 9, and the volume of the filtrate begins to increase, as shown in FIG. 9, until after a certain time the volume of the filtrate with respect to the pressure difference becomes the same as at the beginning of the adjustment.
    This way you can completely clean the filter surfaces. The pressure difference at which the filter surfaces are clogged is determined by the change in the concentration of the feed slurry. The more uniform the suspension concentration, the closer to the specified limit the pressure difference can be chosen, and vice versa. It is also advisable to provide a filter sieve with a high-frequency radiator, due to the use of vibration of which the surface friction on the filter surface becomes less pronounced, which leads to a decrease in resistance to both the flow of the suspension and the filtrate. In addition, the vibrations to a certain extent agitate the fibers in the stream, the concentration profile of the suspension in the stream becomes more uniform, Tte. the concentration does not increase dramatically near the filter surface.
    权利要求:
    Claims (9)
    [1]
    Claim 1. A method of thickening a fibrous suspension by separating a filtrate under the influence of a pressure difference acting on a filtering surface, including supplying the fibrous suspension to a channel formed by filtering surfaces, separating the filtrate when the suspension moves through the channel in the form of a piston flow consisting of fiber mesh, and controlling the amount of filtrate withdrawn and the flow rate of the slurry through the channel by adjusting the pressure difference across the filter surface so that The internal friction of the suspension in the flow exceeds the surface friction of the flow and the filtering surface, characterized in that, in order to increase the efficiency of the process, the filtrate is separated by continuously or stepwise decreasing the flow rate of the suspension in the direction of its movement through the channel.
    [2]
    2. A process according to claim 1, characterized in that the filtrate is separated in successive steps, one after the other, between which the suspension is homogenized.
    [3]
    3. A method according to claim 1, characterized in that high-frequency vibration is directed to the filter surfaces to reduce surface friction and to prevent fibers from sticking to the surface of the sieve.
    [4]
    4. A device for thickening a fibrous suspension containing a thickening element, having at least one channel of the suspension flow limited by filtering surfaces, installed in a thickening element, at least one distribution element bounding together with the walls of the thickening element a cross-sectional area of the thickening element: that the slurry flow channel section has a circular shape, characterized in that the cross section of the flow channel is variable, increasing in the direction of movement and suspensions.
    [5]
    5. The device according to claim 4, characterized in that the area of the cross section of the flow channel increases stepwise.
    [6]
    6. The device according to claim 5, characterized in that the thickening element contains at least two successively distributed distribution elements, the cross-sectional area of the first distribution element in the direction of movement of the suspension of the distribution element than the second.
    [7]
    7. The device according to claim 4, wherein the cross-sectional area of the flow channel increases evenly in the direction of movement of the suspension.
    [8]
    8. The device according to claim 7, characterized in that at least one of the filtering surfaces bounding the flow channel is conical and positioned so that the cross-sectional area of the channel increases in the direction of movement of the slurry.
    [9]
    9. The device according to claim 4, characterized in that at least one of the surfaces bounding the channel is made flexible in the direction perpendicular to the flow of the suspension.
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    类似技术:
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    SU1043882A1|1985-05-30|Centrifuge
    US2130249A|1938-09-13|Method of filtering sewage and the like
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    同族专利:
    公开号 | 公开日
    JPH0826518B2|1996-03-13|
    EP0274690B1|1993-08-18|
    FI865136A|1988-06-18|
    FI865136A0|1986-12-17|
    AT93287T|1993-09-15|
    FI81137B|1990-05-31|
    US4904395A|1990-02-27|
    EP0274690A1|1988-07-20|
    JPS63227883A|1988-09-22|
    CA1313324C|1993-02-02|
    DE3787089T2|1994-01-05|
    DE3787089D1|1993-09-23|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    SU59828A1|1939-05-31|1940-11-30|П.В. Хвиюзов|Apparatus for thickening suspensions|
    DE1142562B|1960-04-22|1963-01-24|Stamicarbon|Shear classifier|
    US3939075A|1970-10-19|1976-02-17|The Bauer Bros. Co.|Thickening apparatus|
    SU516210A1|1974-01-16|1976-05-30|Предприятие П/Я Р-6429|Photomask|
    US4096060A|1974-09-16|1978-06-20|Fairchild Incorporated|Method utilizing plug flow for separating solids from liquid|
    SE394821B|1975-04-15|1977-07-11|Kamyr Ab|METHOD AND DEVICE FOR DRAINING MOVEMENT SUSPENSIONS|
    SE415202B|1976-12-06|1980-09-15|Sunds Ab|DEVICE FOR CONCENTRATION AND / OR LIQUID TREATMENT OF LIQUID MIXTURES|
    US4136035A|1977-07-26|1979-01-23|Bogomolov Boris N|Apparatus for dehydration of continuously fed flow of suspension|
    GB2009274B|1977-09-28|1982-11-24|Reed International Ltd|Process and apparatus for washing fibre stock in the de-inking of paper|
    SE435400B|1980-01-10|1984-09-24|Kamyr Ab|SILAN SYSTEM FOR DEDUCTION OF LIQUID FROM SUSPENSIONS IN MOVEMENT|
    DE3485871T2|1983-03-10|1993-01-21|Cpc Eng Corp|METHOD FOR INCREASING THE FLOW RATE OF CROSS-CURRENT FILTRATION SYSTEMS.|WO1993006299A1|1991-09-26|1993-04-01|Sunds Defibrator Industries Ab|An arrangement and a method for concentrating a suspension|
    SE470444B|1992-08-18|1994-03-28|Sunds Defibrator Ind Ab|Drainage device comprising vertical piping|
    FI112385B|1998-09-23|2003-11-28|Andritz Oy|Method and apparatus for treating pulp|
    JP2002530188A|1998-11-23|2002-09-17|ゼノン、エンバイロンメンタル、インコーポレーテッド|Filtration of water using immersion membrane|
    US20040007527A1|1998-11-23|2004-01-15|Zenon Environmental Inc.|Membrane filtration device and process|
    US20010052494A1|1999-10-25|2001-12-20|Pierre Cote|Chemical cleaning backwash for normally immersed membranes|
    US20050194315A1|2004-02-27|2005-09-08|Adams Nicholas W.H.|Membrane batch filtration process|
    US20060118487A1|2004-12-07|2006-06-08|Adams Nicholas W H|Membrane filtration process|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    FI865136A|FI81137B|1986-12-17|1986-12-17|FOERFARANDE OCH ANORDNING FOER URVATTNING AV FIBERSUSPENSIONER.|
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