Stirring device of pulping machine bleaching tower

Abstract

The invention discloses a pulping machine bleaching tower stirring device which comprises a stirring assembly, a driving device and a high-pressure jet mixing system, the driving device and the high-pressure jet mixing system are arranged at the bottom of a bleaching tower, the stirring assembly comprises a rotating shaft vertically penetrating through the bottom of the bleaching tower, and the rotating shaft is driven by the driving device to rotate to complete material stirring; the high-pressure jet mixing system comprises a jet ring located at the penetrating position of the bottom of the bleaching tower, a plurality of water outlets are formed in the peripheral side of the jet ring, and a first annular flow channel is formed between the jet ring and the rotating shaft; a sealed upper bearing bracket is arranged below the bleaching tower, a high-pressure dilution water inlet is formed in the upper bearing bracket, and a second annular flow channel in the upper bearing bracket is communicated with the first annular flow channel. The driving device is arranged at the bottom of the bleaching tower, the rotating shaft moment arm is reduced, fatigue fracture of the rotating shaft is avoided, and maintenance is facilitated; through cooperation of the follow-up ring and the positioning static ring, dilution water is obliquely and rotationally sprayed into the bleaching tower, and the mixing uniformity and efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pulping machines, and particularly to a stirring device for a bleaching tower of a pulping machine. Background Art

[0002] In the process of pulping production, bleaching is an important link, and its purpose is to remove the coloring substances in the pulp and improve the whiteness and quality of the pulp. As one of the key equipment of the pulping machine, the stirring device inside the bleaching tower has a crucial impact on the uniform mixing of the bleaching agent and the pulp, the reaction efficiency, and the product quality. However, the traditional bleaching tower stirring device has the following technical defects: First, the driving device is usually installed at the top of the bleaching tower, which requires a crane for cooperation during maintenance, resulting in high maintenance costs. At the same time, the ultra-long rotating shaft is prone to generate a large moment arm effect. Slight deviation in concentricity will cause a huge bending moment at the driving end of the rotating shaft, easily leading to fatigue fracture. Moreover, due to the long moment arm of the rotating shaft, the resistance to drive the stirring blades during rotation is large, the motor power is high, and the energy consumption is high. Second, the mixing efficiency is low. The traditional top-feed method is prone to cause local enrichment of the bleaching agent, insufficient mixing of the material and the bleaching agent, forming "spot bleaching", with low conversion rate of the bleaching agent and incomplete bleaching reaction. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a stirring device for a bleaching tower of a pulping machine to reduce energy consumption, improve mixing efficiency and reduce maintenance costs.

[0004] The technical solution of the present invention is: It includes a stirring component, a driving device and a high-pressure jet mixing system arranged at the bottom of the bleaching tower. The stirring component includes a rotating shaft vertically penetrating the bottom of the bleaching tower, and the rotating shaft rotates under the drive of the driving device to complete material stirring.

[0005] The high-pressure jet mixing system includes a jet ring located at the penetration of the bottom of the bleaching tower. The jet ring is hermetically connected to the bleaching tower through a first sealing structure; a number of water outlets for spraying high-pressure diluted water into the bleaching tower are provided on the circumferential side of the jet ring, and a first annular flow channel is formed between the jet ring and the rotating shaft; a sealed upper bearing bracket is provided below the bleaching tower, and a high-pressure diluted water inlet is provided on the upper bearing bracket. A second annular flow channel is machined between its interior and the rotating shaft, and the second annular flow channel communicates with the first annular flow channel.

[0006] Further: The jet ring includes a follower ring and a positioning static ring; the top of the follower ring is sealed, and it is fixedly connected to the rotating shaft through a connecting component at the cantilever end of the rotating shaft and rotates with the rotating shaft; the upper end of the positioning static ring is nested inside the follower ring, and the outer periphery of its lower end is hermetically connected through the first sealing structure at the penetration of the bleaching tower.

[0007] Furthermore: the first sealing structure includes packing and packing gland, and there is an annular gap at the connection between the positioning static ring and the bleaching tower. A plurality of packings are axially coiled in the annular gap, and the packing gland compresses the packing axially and is screwed to the bottom of the bleaching tower.

[0008] Furthermore: the rotating shaft is fixed by a double-bearing support structure, and the double-bearing support structure includes an upper bearing seat and a lower bearing seat arranged at intervals below the bleaching tower, and the rotating shaft is rotatably connected to the upper bearing seat and the lower bearing seat respectively through bearings.

[0009] Furthermore: the upper bearing seat is arranged in the upper bearing bracket, and the upper end surface of the upper bearing seat is provided with a second sealing structure for preventing dilution water from entering the interior of the bearing.

[0010] Furthermore: the second sealing structure includes a stationary ring assembly fixed on the upper cover of the upper bearing seat and a dynamic ring assembly rotating with the rotating shaft through the shaft sleeve, and an elastic member is pre-pressed in the dynamic ring assembly.

[0011] Furthermore: a plurality of the water outlets are opened obliquely along the rotation direction of the rotation axis.

[0012] Furthermore: the high-pressure dilution water enters the second annular flow channel from the water inlet along the tangential direction of the rotation axis.

[0013] Further: the driving device includes a motor, a gear box is provided at the output end of the motor, and the output end of the gear set in the gear box is transmission-connected to the bottom end of the rotating shaft through a transmission assembly.

[0014] Furthermore: the transmission assembly includes synchronous wheels respectively installed on the output end of the gear set and the rotating shaft, and the two sets of synchronous wheels are connected by a synchronous belt transmission.

[0015] The beneficial technical effect of the present invention is that by arranging the driving device at the bottom of the bleaching tower, the lever arm of the rotating shaft is greatly shortened, the energy consumption of the motor is greatly reduced, and the risk of the rotating shaft breakage is avoided. At the same time, the rotating shaft is fixed with a double-bearing support structure to better limit the radial runout of the rotating shaft, ensure the coaxiality of the rotating shaft, and reduce equipment failures and leakage problems caused by coaxiality deviation.

[0016] Through the cooperation between the follower ring and the positioning static ring, the dilution water is sprayed obliquely and rotated into the bleaching tower to complete the full coverage, so that the pulp and the dilution water are fully mixed at the same time, the conversion rate of the bleaching agent is improved, and the bleaching effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 The present invention Figure 1Schematic diagram of local structure;

[0019] Figure 3 It is a schematic diagram of the specific structure of the high-pressure injection mixing system of the present invention;

[0020] Figure 4 is a schematic diagram of the specific structure of the second sealing structure of the present invention;

[0021] Wherein: 1. bleaching tower; 2. driving device; 21. motor; 22. gear box; 23. transmission assembly; 3. stirring assembly; 31. rotating shaft; 32. stirring blade; 4. high-pressure jet mixing system; 41. jet ring; 411. follower ring; 412. positioning static ring; 42. water outlet; 43. upper bearing bracket; 44. water inlet; 5. first sealing structure; 51. packing; 52. packing gland; 6. upper bearing seat; 7. lower bearing seat; 8. lower bearing bracket; 9. second sealing structure; 91. static ring assembly; 92. dynamic ring assembly; 93. elastic member; 94. auxiliary sealing member. DETAILED DESCRIPTION

[0022] In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0023] like Figures 1 to 2 As shown, a pulping machine bleaching tower stirring device according to the present invention comprises a driving device 2 arranged at the bottom of the bleaching tower 1 and a stirring component 3 for stirring materials. The stirring component 3 rotates under the drive of the driving device 2 to stir the materials.

[0024] The driving device 2 includes a motor 21, and a gear box 22 is provided at the output end of the motor 21. A gear set is provided in the gear box 22 to reduce the rotation speed and increase the torque. The output end of the gear set is connected to the bottom end of the rotating shaft 31 through a transmission assembly 23. The transmission assembly 23 includes synchronous wheels respectively installed on the output end of the gear set and the rotating shaft 31, and the two sets of synchronous wheels are connected through a synchronous belt transmission. This structure sets the driving device 2 at the bottom of the bleaching tower 1, which is different from the traditional top installation method, saves the link of crane coordination during maintenance, and greatly reduces the difficulty and workload of maintenance. The transmission assembly 23 is designed to shift the motor 21 to avoid the area directly below the bleaching tower 1, so as to avoid damage to the motor 21 due to maintenance work or accidental leakage of the bleaching tower 1.

[0025] The stirring assembly 3 includes a rotating shaft 31 vertically penetrating through the center of the bottom of the bleaching tower 1. A number of stirring blades 32 are evenly arranged on the circumferential side of the rotating shaft 31 within the bleaching tower 1. The rotating shaft 31 is fixed by a double-bearing support structure and rotates under the drive of the driving device 2 to realize the stirring of the material by a number of stirring blades 32.

[0026] A high-pressure jet mixing system 4 is also provided at the bottom of the bleaching tower 1. As Figure 3 shown, the high-pressure jet mixing system 4 includes a jet ring 41 located at the penetration of the bottom of the bleaching tower 1; water outlets 42 for spraying high-pressure dilution water into the bleaching tower 1 are provided on the jet ring 41, and a number of the water outlets 42 are evenly distributed along the circumferential side of the jet ring 41 to ensure the uniform distribution of the dilution water. A first annular flow channel is formed between the jet ring 41 and the rotating shaft 31; a sealed upper bearing bracket 43 is provided below the bleaching tower 1, and a high-pressure dilution water inlet 44 is provided on the upper bearing bracket 43. A second annular flow channel is machined between its interior and the rotating shaft 31, and the second annular flow channel communicates with the first annular flow channel and constitutes a conveying channel for the high-pressure dilution water.

[0027] In this embodiment, the jet ring 41 includes a follower ring 411 and a positioning static ring 412; specifically, the top of the follower ring 411 is designed with a seal and is fixedly connected to the rotating shaft 31 through a connecting component at the cantilever end of the rotating shaft 31 and rotates with the rotating shaft 31. The upper end of the positioning static ring 412 is nested inside the follower ring 411, and the fit tolerance between the two is controlled within a very small range to ensure concentricity and reduce water flow turbulence and energy loss. The outer periphery of the lower end of the positioning static ring 412 is welded or flange-connected to the bleaching tower 1 at the penetration of the bleaching tower 1, and the sealed connection between the positioning static ring 412 and the bleaching tower 1 is realized through a first sealing structure 5.

[0028] When the follower ring 411 rotates with the rotating shaft 31, the high-pressure dilution water ejected from its water outlets 42 will have a rotating tangential velocity, which makes the dilution water form a rotating water flow in the bleaching tower 1. Cooperating with the stirring action of the stirring blades 32, it can mix with the material more fully, improving the mixing uniformity and efficiency. The rotating jet of the rotating follower ring 411 can cover a larger range and reduce the mixing dead angle.

[0029] The positioning static ring 412 plays a positioning role for the follower ring 411, while making the entire jet ring 41 structure more stable and preventing leakage.

[0030] The first sealing structure 5 includes packing 51 and a packing gland 52. There is an annular gap at the connection between the positioning static ring 412 and the bleaching tower 1. A number of packings 51 are wound axially in the annular gap and axially compressed by the packing gland 52. The packing gland 52 is fixed to the bottom of the bleaching tower 1 by screws..

[0031] The first annular flow channel is jointly formed by the annular gap between the inner hole of the packing gland 52 and the rotating shaft 31, and the annular gap between the inner wall of the injection ring 41 and the rotating shaft 31.

[0032] The double-bearing support structure includes an upper bearing seat 6 and a lower bearing seat 7 that are spaced below the bleaching tower 1. The upper bearing seat 6 is installed in the upper bearing bracket 43; the lower bearing seat 7 is installed below the upper bearing bracket 43 through the lower bearing bracket 8. The rotating shaft 31 is rotatably connected to the upper bearing seat 6 and the lower bearing seat 7 through bearings respectively.

[0033] In this structure, the upper bearing seat 6 and the lower bearing seat 7 provide two supports for the rotating shaft 31, reducing the lever arm, enabling the rotating shaft 31 to rotate stably, better withstanding the torque during operation, and reducing the risk of damage to the rotating shaft 31 or the bearings caused by excessive torque; moreover, the two spaced upper bearing seat 6 and lower bearing seat 7 can better limit the radial runout of the rotating shaft 31, ensure the coaxiality of the rotating shaft 31, and reduce equipment failures and leakage problems caused by coaxiality deviation.

[0034] To prevent dilution water from seeping into the bearings and causing lubrication failure or corrosion, a second sealing structure 9 for preventing dilution water from entering the interior of the bearings is provided on the upper end face of the upper bearing seat 6, such as Figure 4 The second sealing structure 9 adopts a single-end mechanical sealing structure, including a stationary ring assembly 91 fixed on the upper cover of the upper bearing seat 6 and a rotating ring assembly 92 that rotates with the rotating shaft 31 through a shaft sleeve. An elastic member 93 is pre-pressed in the rotating ring assembly 92. When the sealing surface wears or the rotating shaft 31 axially moves, compensation is made through the elastic member 93 to maintain the sealing surface specific pressure. The elastic member 93 can adopt multiple springs or bellows.

[0035] The second sealing structure 9 further includes auxiliary seals 94, that is, including a first sealing ring provided at the docking end face between the rotating ring assemblies 92, a second sealing ring provided at the docking end face between the rotating ring assembly 92 and the rotating shaft 31, and a third sealing ring provided at the docking end face between the rotating ring assembly 92 and the stationary ring. The first sealing ring is used for floating sealing between the rotating ring assemblies 92; the second sealing ring is used to ensure the sealing between the rotating ring and the shaft sleeve; the third sealing ring mainly functions as a seal between the stationary ring and the rotating ring, and also plays a role in floating and buffering.

[0036] Furthermore, to reduce the energy loss of the high-pressure dilution water, the high-pressure dilution water enters the second annular flow channel from the water inlet 44 along the tangential direction of the rotation of the rotating shaft 31. By utilizing the centrifugal force of the rotating shaft 31, the circumferential distribution of the dilution water in the second annular flow channel is enhanced, avoiding energy loss caused by direct radial impact.

[0037] Furthermore, in order to strengthen the turbulence, in this embodiment, the water outlet 42 is inclinedly opened along the rotation direction of the rotating shaft 31. The centrifugal force of the rotating shaft 31 is utilized to enhance the jet kinetic energy, reduce the flow resistance. At the same time, the oblique jet makes the dilution water form a spiral upward flow field, prolongs the contact time with the material, and improves the mixing efficiency. Meanwhile, the caliber of the water outlet 42 is designed in coordination with the conveying pressure of the dilution water, ensuring the efficient and stable operation of the system while ensuring the full coverage of the dilution water.

[0038] The high-pressure dilution water is sprayed into the bleaching tower 1 from the water outlet 42 at a high speed with a relatively high flow rate, and strongly impacts the material falling from a high place in the bleaching tower 1, causing the material particles to be dispersed by the dilution water. At the same time, the two penetrate, mix and complete pre-mixing under the action of the impact force. Due to the countercurrent, the contact time between the two phases is prolonged, the penetration rate of the dilution water to the material is increased, and the bleaching reaction is more thorough. At the same time, the high-pressure dilution water enters the bleaching tower 1 at a relatively high flow rate, generating turbulence, which is superimposed on the shear force generated by the rotation of the stirring paddle 32 to form multi-scale eddies, accelerating the mass transfer between the material and the dilution water, greatly shortening the mixing time, and avoiding fiber damage caused by too high local concentration.

[0039] In the traditional bleaching tower 1, the rotating shaft 31 penetrates through the top of the bleaching tower 1 and extends to the bottom of the bleaching tower 1. Its ultra-long rotating shaft 31 structure forms a great lever arm effect. When there is a slight deviation in the concentricity of the rotating shaft 31, a huge bending moment will be generated at the driving end, resulting in stress concentration and causing fatigue fracture. And replacing the rotating shaft 31 requires setting up a special scaffold inside the bleaching tower 1, which is time-consuming and laborious. At the same time, due to the long lever arm of the rotating shaft 31, the resistance to rotating and driving the stirring paddle 32 is large, the power of the motor 21 is high, and the energy consumption is high.

[0040] In this structure, the cantilever end of the rotating shaft 31 is located at the bottom of the bleaching tower 1, and the rotation of the rotating shaft 31 is driven by reducing the speed through the internal gear set in the gearbox 22 and then driving the transmission component 23. The rotation of the rotating shaft 31 drives the stirring paddle 32 to complete the material stirring. This greatly reduces the energy consumption of the motor 21, also avoids the risk of fracture of the rotating shaft 31, and at the same time reduces the configuration of the stirring paddle 32, reducing the cost.

[0041] The chemical reaction process in the bleaching tower 1 is as follows: The bleaching agent usually uses hydrogen peroxide (H2O2). The material is added from the top or side of the bleaching tower 1, and the high-pressure dilution water is sprayed obliquely upward from multiple water inlets 44, forming a countercurrent mixture with the falling pulp, ensuring full coverage of the alkaline environment with Ph > 7. H2O2 decomposes into active HOO - , and the lignin chromophore is bleached by HOO - oxidation.

[0042] The feeding method of the traditional bleaching tower 1: Diluted water and materials are both added from the top or side of the bleaching tower 1, and the mixing is realized by relying on the stirring paddle 32. In this method, the diluted water is easily enriched in local areas, resulting in a low conversion rate of H2O2; at the same time, the pulp forms spot bleaching due to insufficient mixing with the diluted water, and the bleaching effect is poor.

[0043] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A stirring device for a pulping machine bleaching tower, characterized in that: The invention comprises a stirring assembly (3), a driving device (2) and a high-pressure jet mixing system (4) arranged at the bottom of a bleaching tower (1), wherein the stirring assembly (3) comprises a rotating shaft (31) vertically penetrating the bottom of the bleaching tower (1), and the rotating shaft (31) rotates under the drive of the driving device (2) to complete material stirring; The high-pressure jet mixing system (4) comprises a jet ring (41) located at a penetration point at the bottom of the bleaching tower (1); a plurality of water outlets (42) for spraying high-pressure dilution water into the bleaching tower (1) are provided on the circumferential side of the jet ring (41); a first annular flow channel is formed between the jet ring (41) and the rotating shaft (31); a sealed upper bearing bracket (43) is provided below the bleaching tower (1); a high-pressure dilution water inlet (44) is provided on the upper bearing bracket (43); a second annular flow channel is machined between the interior of the upper bearing bracket and the rotating shaft (31); the second annular flow channel is communicated with the first annular flow channel.

2. A stirring device for a pulping machine bleaching tower according to claim 1, characterized in that: The injection ring (41) comprises a follower ring (411) and a positioning static ring (412); the top of the follower ring (411) is sealed and is fixedly connected to the rotating shaft (31) through a connecting component at the cantilever end of the rotating shaft (31) and rotates with the rotating shaft (31); the upper end of the positioning static ring (412) is nested inside the follower ring (411), and the outer periphery of the lower end is located at the penetration point of the bleaching tower (1) to achieve a sealed connection through a first sealing structure (5).

3. A stirring device for a pulping machine bleaching tower according to claim 2, characterized in that: The first sealing structure (5) comprises a packing (51) and a packing gland (52); an annular gap is provided at the connection between the positioning stationary ring (412) and the bleaching tower (1); a plurality of packings (51) are axially coiled in the annular gap; the packing gland (52) compresses the packing (51) axially and is screwed to the bottom of the bleaching tower (1).

4. A stirring device for a pulping machine bleaching tower according to claim 1, characterized in that: The rotating shaft (31) is fixed by a double-bearing support structure, wherein the double-bearing support structure comprises an upper bearing seat (6) and a lower bearing seat (7) which are arranged at intervals below the bleaching tower (1), and the rotating shaft (31) is rotatably connected to the upper bearing seat (6) and the lower bearing seat (7) respectively by bearings.

5. A stirring device for a pulping machine bleaching tower according to claim 4, characterized in that: The upper bearing seat (6) is arranged in the upper bearing bracket (43), and the upper end surface of the upper bearing seat (6) is provided with a second sealing structure (9) for preventing dilution water from entering the interior of the bearing.

6. A stirring device for a pulping machine bleaching tower according to claim 5, characterized in that: The second sealing structure (9) comprises a stationary ring assembly (91) fixed on the upper cover of the upper bearing seat (6) and a dynamic ring assembly (92) rotating with the rotating shaft (31) through a shaft sleeve, and an elastic member (93) is pre-pressed in the dynamic ring assembly (92).

7. A stirring device for a pulping machine bleaching tower according to claim 1, characterized in that: The plurality of water outlets (42) are opened obliquely along the rotation direction of the rotation axis (31).

8. The stirring device for a pulping machine bleaching tower according to claim 1, characterized in that: The high-pressure dilution water enters the second annular flow channel from the water inlet (44) along the tangential direction of the rotation of the rotation shaft (31).

9. A stirring device for a pulping machine bleaching tower according to claim 1, characterized in that: The driving device (2) comprises a motor (21), a gear box (22) is provided at the output end of the motor (21), and the output end of the gear set in the gear box (22) is transmission-connected to the bottom end of the rotating shaft (31) via a transmission assembly (23).

10. A stirring device for a pulping machine bleaching tower according to claim 9, characterized in that: The transmission assembly (23) comprises synchronous wheels respectively mounted on the output end of the gear set and the rotating shaft (31), and the two sets of synchronous wheels are connected by synchronous belt transmission.

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