A device for washing the wood fiber supply

 

(57) Abstract:

The invention relates to a device for washing the wood fiber supply, mainly to improved device for washing the cellulose fibers. The essence of the invention lies in the fact that the device for washing, containing a hollow body, a stationary wash the grid chamber for collecting fluid, formed by the grid and the housing, means for feeding the mass flow and wash liquid and removing the liquid passing through leaching grid, there is a rotating tool. This tool represents a rotor to provide a high-frequency low-amplitude pulses in the mass, passing along a grid having a cylindrical surface, and rinsing the mesh is made in the form of shells. Cylindrical surface of the rotor has a large number of outgoing edges. The tabs have a hemispherical shape. Given the design of the chamber for collecting fluid. 4 C.p. f-crystals, 2 Il.

The invention relates to a device for washing the wood fiber supply, and more specifically to an improved device for washing the cellulose fibers.

When the wood is subjected to chemical treatment to obtain cellulose is Noah chips using different cooking liquids, when this resin and materials, linking the cellulose fibers dissolve in the cooking fluid and the release of fibers. The result is a liquid mass of fibers suspended in an aqueous solution, which consumes chemicals or solution. For further cooking of the pulp used for paper production, the fibers must be separated from the liquid, the liquid is removed and the fibers are subjected to washing to remove those chemicals that remain together with the fibers.

Washing of the pulp is to separate the soluble impurities from the cellulose fibers in order to obtain cellulose, in which there are virtually no impurities. The optimal system for pulp washing must remove the spent solution and other impurities, using the minimum amount of wash liquid. For regeneration chemicals and/or other subsequent processing of the spent solution from any rinsing liquid that is added during the stage of leaching, must also be processed through evaporation or other means. It is therefore desirable to minimize the amount of wash liquid added during the washing process so that the RNO involved in the process chemicals in the later stages of processing.

When evaluating the efficiency of washing systems in the paper industry adopted the term "dilution factor" which determines the number of used washing liquid. The coefficient can be defined as the amount of water or other washing liquid fed into the system and do not take away from the system washed pulp when the pulp is removed from the system. If the quantity of wash liquid added is equal to the quantity of wash liquid, leaving the system with cellulose, the dilution factor is equal to zero. Therefore, the most desirable small values of the dilution factor.

A device for washing wood fibrous mass containing a hollow housing forming a pressure compartment mass flow of cellulose fibers in the carrier liquid. The case has a hole for feeding the stock in the inlet zone and the outlet for its output, a stationary cylindrical leaching grid located in the pressure compartment, creating a barrier for the passage of cellulose fibers from one side of the grid to the opposite side and providing a passage through it of the carrier fluid into the chamber for collecting fluid, formed by the grid and the housing. The device contains yunwu grid, means for creating an axial velocity in the direction of flow of the mass from the input area of the device to the output zone, a tool for creating radial velocity for dehydration of mass moving along the grid from its first end on the second rotating means mounted coaxially with a wash mesh inside the volume occupied by the grid, with the formation of a gap between them to ensure the passage of the mass of the means of its delivery to the specified gap and localized mixing of the mass along the wash nets (see application UK N 2009274, class D 21 C 9/02, 1979).

A disadvantage of the known device is the necessity of using high mass concentration at low speed rotating means, while the invention provides for a low concentration and high speed. The result is that a relatively small device according to the invention gives significantly better performance than the known device.

This is achieved by the fact that the rotating means is a rotor to provide a high-frequency low-amplitude pulses in the mass, passing along a grid having a cylindrical surface, and rinsing the grid imp who have a hemispherical shape. Chamber for collecting fluid has a means of diversion from her part of the fluid passing through the second end of the mesh to the input area of the device. Chamber for collecting fluid has at least two compartments, one of which is located closer to the first end of the grid for collecting fluid passing through the first end of the grid, and the second part is located closer to the second end of the grid for collecting fluid passing through the second end of the grid.

In Fig. 1 shows a schematic vertical section showing a device for washing the pulp, constructed and operating according to the principles of the invention; Fig. 2 is a view in vertical cross section of the preferred alternative implementation of the device for washing the wood fiber supply, which operates in accordance with the principles of the present invention.

A device for washing the wood fiber supply according to the invention includes a hollow body 1, forming a pressure compartment mass flow, and a rotary site 2 located in the housing in the axial direction. The main shell or casing 1 is divided into three main areas. The first area that the input area 3, located in front of the industry the first part of the casing with the to submit fibrous mass containing cellulose fibers in a carrier liquid, to promiseme device with the velocity tangential to the axis of the apparatus through the opening for feeding the stock.

The second area inside the housing 1 is a leaching zone 5, which can be divided into several teeth at the outer surface of the shell for the extraction of wash solutions. Cylindrical wash mesh, made in the form of the shell 6, is located along the wash zone, isolating the pipeline 7 to the filtrate (carrier fluid passing through the mesh), located in the upper part of the casing, a rotary site 2, located in the axial direction inside the washing machine, and washing mesh, with a gap in relation to it. Hence, the reach of the pipeline to the filtrate, only the fluid that passes through leaching grid. Wash the mesh forms a barrier along which separates the fibers from the solution.

The third area of the body represents the output area 8 located at the rear part of the washing apparatus at the opposite end of the rotor and the network from the input zone is the zone in which the washed pulp mass is discharged from promyvaete. These compartments separated by a partition 11. Wash (fresh) water is introduced from the rear side of the washing device through the input means in the form of pipeline 12. The number of added fresh water is controlled by control valve 18. The solution in the pulp mass is displaced by fresh water through leaching and mesh extracted into the compartment 10. After washing, the pulp is produced through the hole to exit the washing machine on line 19. The filtrate (the liquid passing through the grid) from the Department of 10 is entered with the input side of the washing apparatus through the pipeline 13 without using the pump only on the basis of the pressure difference. The pressure in the Central zone of the leaching apparatus below the pressure at the place of issue of the filtrate from the Department 10. However, it is obvious that the pump can also be used.

The filtrate is entered from the input side of the washing apparatus through the pipeline 13 is used for internal dilution. Since the filtrate has a lower concentration than the solution already present in the pulp mass, when the filtrate displaces the solution of higher concentration in this zone, which is transported to the compartment 9 through leaching mesh, pulp and fiber liberation is launched from the washing machine through the pipe 7 to the filtrate.

The flow through the inlet pipe 4, line 7 for leachate concentration, the pipeline 13 for recirculation of the filtrate, line 19 output washed pulp and the pipeline 12 for fresh water is controlled by valves 14, 15, 16, 17 and 18, in order to maintain the stable operation of the washing machine by creating a pressure drop across the mesh between the inner and outer surfaces, and the washing machine between the entrance pulp and exit the wash pulp.

Next with reference to Fig.2 will be given a more specific description of the preferred variant of the invention, schematically disclosed in Fig. 1. In Fig.2 position 100 indicated a device for washing the wood fiber supply, designed to operate in accordance with the principles of the invention. The housing 110, preferably made of stainless steel or similar material, includes an outer, actually cylindrical shell 112 having a flange 114 for going down on him cover 116 at the input end of the leaching apparatus. The housing 110 additionally includes actually cone-shaped portion 118 at the input end of the leaching apparatus.

Genie in motion attached to the motor 124 and is connected to the housing 126, having a large number of heads or bumps 128 on its outer surface. The rotor described hereinafter, often referred to as the rotor fractionation of the type that generates in the pulp mass pulses of high frequency and low amplitude. Bumps 128 may have a hemispherical or other shape.

The inlet area 130 is generally formed by a cover 116, a part of the shell 120, the flange 132 of the inner shell and face 136 of the housing 126 of the rotor. The inlet pipe 140 provides a supply of liquid pulp intended for washing, to the intake zone 130. The orientation of the inlet pipe 140 with respect to the rotor axis of the rotor and the inlet zone is to provide a substantial tangential velocity pulp.

The inner wall 142 of the shell 112 holds the rotary node 120 by bearings 144, which enters the shaft 122 of the rotor. The wall 142 includes a flange 146. The flange 132 with one end of the leaching apparatus and the flange 146 with its other end in General define the inlet and outlet edges of the wash zone 150, which receives the pulp from the inlet zone 130.

Wash the grid 160 is connected to the flanges 132 and 144 through its mounting flanges 162 respectively) smooth, and has holes or slits, small enough to restrict the passage of cellulose fibres under the action of pulses from the rotary node 120. It is established that the slits constituting of 0.015 cm in the construction of shells work well enough, but acceptable cuts in the range from 0.005 to 0.03 cm and openings in the range of 0,01-0,03 see

Wash the mesh 160 forms a stationary barrier, along which the pulp flows from the input of which the pulp flows from the input end of the washing device to its output end. Wash the mesh close separated from the body 126 of the rotor with protuberances 128 on it and share leaching area 150 on the radial inner and radial outer part. The pulp from the input zone 130 enters the radial inner portion of the wash zone through the space 166 between the rotor and the inner surface of the leaching grid. Fluid displaced from the pulp to flow through the slots in the grid to the radial outer part of the wash zone 150. Some or all of the displaced fluid may be directed from the washing device through the output 170 for the filtrate, while the washed pulp mass is fed from the washing machine through the exit 180 190 200 through the septum 210. It is clear that can be used two or more partitions such as partition 210 to form three or more washing zones, such zones 190 and 200.

The pulp enters the space 166 between the outer surface of the rotor node 120 and the inner surface of the leaching grid 160 and flows along the wash of the grid due to the continuing pressure difference between input and output. Line 220 washing liquid made in the wall 142 and provides a supply of this fluid, which displaces the solution in the pulp mass, and the solution is removed through leaching grid and enters the sub-190 and 200. Line 230 for recirculation of the filtrate gives a filtrate from a sub-200 to the input 232 for recirculating the filtrate is made in the cover 116.

The fibers are designed for washing, summarized in the form of liquid pulp by means not shown, to the intake pipe 140, while the pulp is produced tangentially to promiseme the apparatus in the inlet zone 130. Liquid pulp mass, consisting of mortar and fiber consistency of 0.2 to 4.5% and preferably from 3.0 to 3.5% is applied at a temperature of 93oC to promiseme machine.

Liquid in pivnoy area 150 on the way, in fact, parallel to wash the grid 160. The fibers are difficult to pass through the grid because of the angle of their approach to the slots. Fiber is moved in the axial direction from the input zone 130 to intended for the washed pulp output 180 of the washing device.

There are three main components of the speed force inside the washing machine to facilitate the flushing mechanism. These components are axial, radial and tangential velocity. The axial velocity is directed along the axis of rotation of the washing machine and generally parallel to wash the surface of the grid. This speed is controlled by the pressure difference between the inlet pulp and exit the washed pulp. This axial velocity is affected by the size of the annular gap between the wash grid and the rotor housing and the volume of flow toward the exit pulp.

Radial velocity is directed through leaching grid. This speed is controlled by the pressure difference between inlet for pulp and access to the washed filtrate. Radial velocity depends on the total area of the leaching mesh, square hole mesh and the volume of flow of the filtrate.

Tangential is ity largely depends on the design of the rotor.

Speed in the washing machine create radial traction, cutting efforts and turbulent efforts together mix, re-turn in the liquid mass and dehydrate the pulp mass to obtain the desired degree of leaching efficiency in the wash area.

Due to the shear velocity, which is a combination of the velocities generated in the washing machine, the available effective size of the openings of the mesh fibers, the current through the washing apparatus can be reduced. This decrease is visible holes of the mesh is an important mechanism for the effective separation of the liquid from the pulp. The pressure difference created between the interior of the leaching apparatus and chamber for filtrate, provides fluid flow through leaching grid. However, fiber, affected by shear velocity, will not pass through the openings of the grid, which would ensure the passage of the fiber if the fiber was influenced by only the radial velocity. The pulp inside the washing machine reaches a higher consistency than the consistency of the input, due to the extraction liquid.

Cellisvallen, mixing, extraction and displacement. The efficiency of the process depends on the degree of equilibrium reached under stirring, and the degree of extraction and the displacement achieved in the specific conditions of the leaching apparatus. A high degree of mixing is achieved in that the washing apparatus through the work of the high-speed rotor in close proximity to the wash of the grid. This quickly provides a uniform concentration of the solution at any point of the leaching apparatus, when the solution of a high concentration in the pulp mass is mixed with a solution of low concentration or fresh water. This solution after reaching equilibrium concentration is extracted through a grid.

The device performs two stages of washing, but for professionals it is obvious that it can be extended to introduce a single system of any number of stages.

A device for washing the wood fiber supply creates trubulence liquid displacement in contrast to the previously known static displacement. Preemption is more efficient and the device can vary according to the size of one third of the comparable, for example, a drum washing machine.

the e these goals and distinctive features. However, it is clear that without deviating from the scope of the invention it can be made various changes.

1. A device for washing the wood fibrous mass containing a hollow housing forming a pressure compartment mass flow consisting of cellulose fibers in the carrier fluid, the housing has a hole for feeding the stock in the inlet zone and the outlet for its output, a stationary cylindrical leaching grid located in the pressure compartment, creating a barrier for the passage of cellulose fibers from one side of the grid to the opposite side and providing a passage through it of the carrier fluid into the chamber for collecting fluid, formed by the grid and the housing, feed means for introducing wash liquid, displacing and replacing the fluid passing through leaching grid, means for creating an axial velocity in the direction of flow of the mass from the input area of the device to the output zone, a tool for creating radial velocity for dehydration of mass moving along the grid from the first end to the second rotating means mounted coaxially with a wash mesh inside the volume occupied by the grid, with the formation of a gap between them to ensure that al leaching grid characterized in that the rotating means is a rotor to provide a high-frequency low-amplitude pulses in the mass, passing along a grid having a cylindrical surface, and rinsing the mesh is made in the form of shells.

2. The device under item 1, characterized in that the cylindrical surface of the rotor has a large number of outgoing edges.

3. The device according to p. 2, characterized in that the protrusions are hemispherical in shape.

4. The device according to PP.1 to 3, characterized in that chamber for collecting fluid has a means of diversion from her part of the fluid passing through the second end of the mesh to the input area of the device.

5. The device according to p. 4, characterized in that chamber for collecting fluid has at least two compartments, one of which is located closer to the first end of the grid for collecting fluid passing through the first end of the grid, and the second part is located closer to the second end of the grid for collecting fluid passing through the second end of the grid.

 

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