Self-adaptive anti-climbing rod anti-drag stirring shaft

Abstract

The utility model relates to a self-adaptive anti-pole-climbing anti-drag stirring shaft, which is suitable for stirring a polymer solution with a pole-climbing effect and comprises a stirring auxiliary shaft and a stirring shaft, the stirring shaft is rotatably connected with the stirring auxiliary shaft through a bearing arranged at the upper part of the stirring shaft, and a shearing structure is arranged at the lower part of the stirring shaft. And a driven stirring paddle is fixed on the outer side of the lower part of the stirring countershaft. According to the utility model, direct contact between the stirring shaft rotating at a high speed and the polymer fluid in the container is avoided through the stirring countershaft, and linear polymers in the polymer fluid cannot stretch on the stirring countershaft under the condition that the paddle of the driven stirring paddle and the fluid circulation in the container keep a lower rotating speed difference and the horizontal circulation is weakened; macromolecules only show weak elasticity, so that no power is generated to generate a pole climbing effect, the power of the passive stirring paddle comes from the horizontal circulation of the fluid, and meanwhile, the anti-climbing pole reduces the work of the stirring shaft on the macromolecule fluid, so that the aims of saving energy and reducing consumption are fulfilled according to the principle.

Description

Technical Field

[0001] The utility model relates to the technical field of polymer material processing, in particular to a drag-reducing stirring shaft of an adaptive anti-climbing rod. Background Art

[0002] Polymer materials are indispensable in the chemical industry. During the processing and stirring of polymer liquids, polymer liquids will gather toward the stirring shaft. In severe cases, the liquid will leave the bottom and climb to the top of the container. This phenomenon is called the Weissenberg effect, also known as the climbing rod effect and the axis wrapping effect. The reason for this effect comes from the elasticity of polymers. When polymer liquids are subjected to rotational shear stress, due to the elasticity of the molecular chains, the molecular chains are reoriented and stretched in the circumferential direction of the flow, and the elastic tension generated causes the fluid to gather toward the stirring shaft. The climbing rod effect affects the mass transfer, heat transfer, dispersion effect and energy utilization efficiency of the production process. Driven by demand, a variety of anti-climbing rod structural devices have been developed to solve the climbing rod effect of polymer liquids.

[0003] From the perspective of the principle of anti-climbing pole devices, existing anti-climbing pole devices can be roughly divided into three categories: one is to use arc-shaped structures or special-shaped stirring paddles to prevent the fluid from climbing upward; the second is to use a threaded structure to apply a reverse force in the circulation direction of the polymer fluid to suppress or offset the upward climbing of the fluid; the third is to shear-thin the polymer fluid through high-speed rotation near the stirring shaft to destroy the climbing conditions of the polymer fluid. The three structures are usually used in combination.

[0004] However, these three types of structures may also have anti-climbing rod failures. The reasons for failure are analyzed as follows: when the structural parts are not adjustable, they are suitable for anti-climbing rod scenarios with stirring viscosity less than a certain value. Once this limit viscosity is exceeded, the polymer fluid will cross the anti-climbing rod structure, causing the anti-climbing rod structure to fail. For example, in the prior art, the coaxial reverse threaded stirring auxiliary propeller driven by a driving motor has a stirring speed that is 5 times that of the main stirring propeller, and its rotation speed is adjustable, which reflects the use scenario of coping with a wide range of viscosity changes.

[0005] However, the existing anti-climbing poles have irregular structures, introduce extra energy consumption, have anti-climbing pole failure, and are not adjustable. Therefore, it is of great significance to design an anti-climbing pole device that is simple, adjustable, has no failure problems, and is energy-saving. Utility Model Content

[0006] The utility model aims to provide a drag-reducing stirring shaft with an adaptive anti-climbing rod to solve the problems encountered in the above-mentioned background technology.

[0007] To achieve the above purpose, the technical solution of the utility model is as follows:

[0008] A drag-reducing stirring shaft with an adaptive anti-climbing rod comprises a stirring sub-shaft and a stirring shaft. The stirring shaft is rotatably connected to the stirring sub-shaft via a bearing provided at the top, a shear structure is provided at the bottom of the stirring shaft, and a passive stirring paddle is fixed to the outer side of the lower part of the stirring sub-shaft.

[0009] In the above scheme, the stirring secondary shaft is a hollow cylindrical structure, and a limit block for limiting the descent of the stirring secondary shaft is provided on the outer side of the bottom of the stirring secondary shaft. As a preferred scheme, the diameter of the stirring secondary shaft is the same as the length of the limit block, and there is at least one limit block, which is designed and assembled according to actual installation needs.

[0010] In the above scheme, the shearing structure includes shearing teeth, and the shearing teeth are provided with at least three layers, which are distributed as an upper layer, a lower layer and a middle layer; the upper layer and the lower layer are clockwise downward pressing shearing teeth, and the middle layer is shearing teeth with reverse upper and lower layers.

[0011] Among them, a single shearing tooth is rectangular, with an installation angle of 30-60 degrees, such as 45 degrees, a width of 1-1.5cm, and an installation gap less than 20% of the spacing between the stirring auxiliary shaft and the stirring shaft; the regional spacing between two adjacent layers is 1.5-2.0cm, such as the regional spacing between two adjacent layers is 1.7cm. As a preferred solution, the shearing structure also includes a screw paddle, the height of the screw paddle is the same as the height of the shearing tooth; the ratio of the long diameter of the screw paddle to the screw paddle's own diameter is 1:1, and the length of the screw paddle is 1-2.5 turns of the screw paddle's own diameter.

[0012] In the above scheme, a suction hole and a discharge hole are provided on the outer side of the lower part of the stirring secondary shaft, the suction hole is located on the upper part of the passive stirring paddle, and the discharge hole is located on the lower part of the passive stirring paddle. As a preferred scheme, the suction hole and the discharge hole are staggered, and two suction holes and two discharge holes are respectively provided, and the two suction holes are symmetrically distributed, and the two discharge holes are symmetrically distributed.

[0013] In implementation, the stirring secondary shaft adopts a radial flow impeller with a large annular force area, such as a six-straight-blade disc stirring impeller, a Burmakin type, a double straight-blade, a three-blade swept type, a backward curved-blade open turbine type, and a backward curved-blade disc turbine type. The difference between the inner diameter of the stirring secondary shaft and the diameter of the stirring shaft is 2 to 2.5 cm; the blade length of the passive stirring impeller is 1 / 3-1 / 4 of the container diameter, and the width-to-length ratio is 1 / 4-1 / 5.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] The utility model avoids direct contact between the high-speed rotating stirring shaft 6 and the polymer fluid in the container through the stirring sub-shaft 1. When the blades of the passive stirring paddle 3 and the fluid circulation in the container maintain a low rotation speed difference and the horizontal circulation is weakened, the linear polymer in the polymer fluid cannot stretch on the stirring sub-shaft, and the polymer only shows weak elasticity, and there is no power to produce the climbing rod effect. The power of the passive stirring paddle 3 comes from the horizontal circulation of the fluid. At the same time, the anti-climbing rod reduces the work done by the stirring shaft on the polymer fluid, and this principle is used to achieve the purpose of energy saving and consumption reduction. The horizontal circulation in the stirring and mixing process is not beneficial to the mixing process. The passive stirring paddle 3 consumes the circulation energy and reduces the circulation speed. The passive stirring paddle takes on the role of part of the baffle, so as to achieve the goal of improving the stirring efficiency.

[0016] In the prior art, there is no limiting viscosity problem. When the fluid viscosity of the non-adjustable anti-climbing rod device continues to rise and exceeds the limiting viscosity of the device, the polymer fluid will also "ignore" and cross the anti-climbing rod device. The passive stirring shaft 3 in the drag-reducing stirring shaft is powered by the horizontal circulation of the polymer fluid. The increase in the horizontal circulation velocity can drive the stirring sub-shaft 1 to increase the rotation speed, and keep the speed difference between the polymer fluid and the stirring sub-shaft low in real time. In theory, there is no limiting viscosity problem.

[0017] This solution improves the mixing capacity of the center of the stirring equipment and reduces the stirring resistance: in the prior art, the fluid rotation speed near the stirring shaft 6 is relatively low. If it is not installed eccentrically, it is easy for a single component to gather near the stirring shaft and the mixing is insufficient. The stirring sub-shaft 1 and the stirring shaft 6, the shearing teeth 9 and the suction hole and the discharge hole form a stirring and mixing center with a protective sleeve, which improves the stirring efficiency of the center of the container. After the viscosity increases in the later stage of stirring, the fluid between the stirring sub-shaft 1 and the stirring shaft 6 is shear-thinned under high shear (the phenomenon that the viscosity of polymer fluids becomes lower under strong shear), thereby achieving the purpose of improving the central mixing capacity and reducing the stirring resistance.

[0018] This solution is also simple, highly combinable and expandable: the various special-shaped structures of the anti-climbing rod structure in the prior art, some of which need to enter below the liquid surface, complicate the simulation calculation. The utility model has a simple structure and can simplify the polymer fluid stirring structure and calculation. By changing the stirring paddle bracket and the number and the length of the stirring shaft, it can adapt to the commonly used stirring paddle without affecting the stirring paddle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them:

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0021] Figure 2 It is a schematic diagram of the stirring shaft structure of the utility model which does not include an external stirring auxiliary shaft.

[0022] Numbers in the figure: 1-mixing auxiliary shaft; 2-intake hole; 3-passive mixing paddle; 4-discharge hole; 5-limiting block; 6-mixing shaft; 7-bearing; 8-screw paddle; 9-shearing tooth. DETAILED DESCRIPTION

[0023] In order to make the technical means, creative features, objectives and effects of the utility model easier to understand, the utility model is now further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the relevant components of the utility model.

[0024] According to the technical solution of the utility model, without changing the essential spirit of the utility model, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the utility model, and should not be regarded as the entirety of the utility model or as a limitation or restriction to the technical solution of the utility model.

[0025] The technical solution of the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] Embodiment 1, as Figure 1 and Figure 2 As shown, an adaptive anti-climbing drag-reducing stirring shaft, which is suitable for stirring polymer solutions with climbing effects, includes a stirring sub-shaft 1 and a stirring shaft 6. A conventional stirring paddle for stirring polymer materials is welded to the bottom of the stirring shaft 6 and maintained on the same axis. The stirring shaft 6 is rotatably connected to the stirring sub-shaft 1 through a bearing 7 provided on the upper portion. Two bearings 7 are provided on the upper portion of the stirring shaft 6 to stabilize the transmission torque of the stirring sub-shaft 1 and the stirring shaft 6. The two bearings 7 on the stirring shaft 6 that play a rotating role are installed between the stirring sub-shaft 1 and the stirring shaft 6, and need to meet the installation tolerance. The installation spacing length should be greater than 1 / 2 of the length of the stirring sub-shaft 1 to ensure the stability of the rotation of the stirring sub-shaft 1 and maintain a low rotational resistance.

[0027] A shearing structure is provided at the lower part of the stirring shaft 6, which is used to shear the polymer material climbing the pole during stirring. As a preferred solution, the shearing structure includes shearing teeth 9, which are provided with at least three layers of regions, distributed as an upper layer, a lower layer, and a middle layer, and each region is provided with a number of shearing teeth 9. The upper layer and the lower layer are clockwise downward pressing shearing teeth, and the middle layer is a shearing tooth with reverse layers, which is used to expand the shearing angle and provide resistance to the polymer material climbing the pole to prevent it from continuing to climb the pole.

[0028] Among them, a single shearing tooth 9 is rectangular, the installation angle is 30-60 degrees, for example, 45 degrees, then the reverse angle is 135 degrees, the width is 1-1.5cm, and the installation gap is less than 20% of the spacing between the stirring auxiliary shaft and the stirring shaft. For example, the installation angle of the shearing teeth 9 in the upper and lower regions is 45 degrees, and the installation angle of the shearing teeth 9 in the middle region is 135 degrees. The regional spacing between two adjacent layers is 1.5-2.0cm, for example, the regional spacing between two adjacent layers is 1.7cm, for example, the regional spacing between the lower region and the middle region is 1.7cm.

[0029] In addition, as a preferred solution, the shearing structure also includes a screw paddle 8, and the height of the screw paddle 8 is the same as the height of the shearing teeth 9. The ratio of the long diameter of the screw paddle 8 to the diameter of the screw paddle 8 itself is 1:1, and the length of the screw paddle 8 is 1-2.5 turns of the diameter of the screw paddle 8 itself. During implementation, the installation position length of the shearing teeth 9 is between the screw paddle 8 and the limit block 5, and strong shear and light circulation are performed during rotation. The screw paddle 9 and the stirring sub-shaft 1 work together to force the liquid to be discharged downward, and play a dynamic sealing role to prevent the lower polymer solution from contacting the connecting part of the upper polymer solution.

[0030] A passive stirring paddle 3 is fixed to the outer side of the lower part of the stirring auxiliary shaft 1. The passive stirring paddle 3 adopts a six-straight-blade disc passive paddle during implementation. The passive stirring paddle 3 is driven to rotate only when the polymer physically climbs the rod.

[0031] Embodiment 2, a drag-reducing stirring shaft with an adaptive anti-climbing rod, is based on Embodiment 1, wherein the stirring sub-shaft 1 is a hollow cylindrical structure, and a limit block 5 is provided on the outer side of the bottom of the stirring shaft 6 for limiting the descent of the stirring sub-shaft 1 to prevent the stirring sub-shaft 1 from falling off. As a preferred solution, the diameter of the stirring sub-shaft 1 is the same as the length of the limit block 5, and there is at least one limit block 5. During implementation, the length of the limit block 5 and the stirring shaft 6 is determined according to the installed passive stirring paddle 3. If the installed passive stirring paddle 3 is a frame-type or multi-layer blade, the length of the stirring shaft 6 can be extended and the number of limit blocks 5 can be increased to meet the requirements.

[0032] Embodiment 3, an adaptive anti-pole climbing drag-reducing stirring shaft, based on embodiment 1, is provided with a suction hole 2 and a discharge hole 4 on the lower outer side of the stirring secondary shaft 1, the suction hole 2 is located above the passive stirring paddle 3, and the discharge hole 4 is located below the passive stirring paddle 3. When the stirring secondary shaft 1 rotates, when the polymer physics is climbing the pole, it will enter from the suction hole 2 and flow out from the discharge hole 4, thereby preventing it from continuing to climb the pole.

[0033] As a preferred solution, the suction hole 2 and the discharge hole 4 are staggered, and two suction holes 2 and two discharge holes 4 are respectively provided, and the two suction holes 2 are symmetrically distributed, and the two discharge holes 4 are symmetrically distributed, so as to absorb the high molecular liquid of the climbing rod in a larger range. When the passive stirring paddle 3 is implemented, the optimal working liquid level is located between the screw paddle 8 and the lower end of the suction hole 2, and the installation position is between the lowest rotating bearing 7 and the suction hole 2, which plays the role of forcing the fluid to be discharged with the stirring sub-shaft 1, and dynamically maintains the clean state of the rotating bearing 7. In addition, the suction hole 2 and the discharge hole 4 occupy 10%-20% of the outer surface area of ​​the stirring sub-shaft 1 under the liquid surface, ensuring heat dissipation and flow stability.

[0034] Embodiment 4, a drag-reducing stirring shaft with an adaptive anti-climbing pole, based on the scheme of embodiments 1-3, when implemented, the stirring sub-shaft 1 adopts a radial flow blade with a large annular force area, such as a six-straight-blade disc stirring paddle, Burmakin type, double straight blade, three-blade swept type, backward curved blade open turbine type and backward curved blade disc turbine type, etc., to obtain the rotational torque from the horizontal circulation. The difference between the inner diameter of the stirring sub-shaft 1 and the diameter of the stirring shaft 6 is 2 to 2.5 cm; the blade length of the passive stirring paddle 3 is 1 / 3-1 / 4 of the container diameter, and the width-to-length ratio is 1 / 4-1 / 5, and the container is the stirring drum of the equipment for placing the drag-reducing stirring shaft.

[0035] Based on the scheme described in the above embodiment, the improved structure during the stirring process has an anti-climbing effect, so that the polymer liquid has the functions of adaptive adjustment, improving the central mixing ability, reducing the stirring resistance, saving energy and improving the mixing efficiency during the stirring process.

[0036] When implemented, the principles and processes are as follows:

[0037] The drag-reducing stirring shaft is connected to the power transmission of the driving motor, that is, the stirring shaft 6 is connected to the driving motor, the lower part of the limit block 5 of the drag-reducing stirring shaft is connected to a conventional stirring paddle for stirring polymer materials, the stirring sub-shaft 1 is mounted on the outside of the stirring shaft 6 through a bearing sleeve, the passive stirring paddle 3 is installed on the stirring sub-shaft 1, and is limited on the stirring shaft 6 by the limit block 5.

[0038] Due to the elasticity of the polymer, when the polymer liquid is subjected to rotational shear stress, due to the elasticity of the molecular chain, the curled molecular chain is reoriented and stretched in the circumferential direction of the flow, and the elastic tension generated causes the fluid to shrink and gather in the direction of the drag-reducing stirring shaft. With the help of the stirring shaft 6 with the same rotation direction but faster stirring speed, the power transmission between the stirring shaft 6 and the polymer, and between the polymers, accelerates the continuous climbing of the fluid. The limit viscosity problem and the fixed anti-climbing rod structure, when the viscosity exceeds a limit value, the anti-climbing rod structure fails, and the polymer fluid ignores the structure and climbs upward.

[0039] The power of the climbing pole effect comes from the passive stirring paddle 3 and the stirring shaft 6, and then climbs up with the help of the stirring shaft 6. In this embodiment, the stirring sub-shaft 1 fully isolates the stirring shaft 6 rotating at a high speed and most of the fluids circulating horizontally at a lower speed, blocking the polymer fluid from obtaining power from the speed difference of the stirring shaft, and also isolating the object of the polymer fluid climbing. However, the polymer fluid also has the power obtained by the stirring paddle to rotate horizontally in a circular flow. The stirring sub-shaft 1 obtains power through the blades of the passive stirring paddle 3, maintaining a low speed difference between the stirring sub-shaft 1 and the polymer fluid. Under the low speed difference, the polymer is not stretched sufficiently, and with the elastic force of climbing being less than its own gravity, the polymer fluid can only return to the container downward. The blades of the passive stirring paddle 3 are unpowered, and power is obtained through horizontal circulation. When the horizontal circulation speed increases, the speed of the stirring sub-shaft 1 will increase synchronously, and there is no limit viscosity problem. The above principles of this embodiment realize the anti-climbing pole effect, and realize adaptive adjustment, and can also avoid limit viscosity.

[0040] During the stirring process, due to the low linear velocity near the axis and the centrifugal effect of the stirring paddle, the liquid level is low in the middle and high on both sides. In the early stage of the reaction, the raw materials will inevitably gather near the stirring center. The stirring process is mainly for mixing, and the axial circulation capacity needs to be improved. The annular circulation of the horizontal circulation is useless work done by the stirring paddle. Baffles are usually added to weaken the circulation and enhance the mixing efficiency. In high shear stirring scenarios, the viscosity of polymer fluids will decrease, that is, shear thinning.

[0041] In summary, the utility model improves the stirring efficiency of the center of the container by forming a stirring mixing center with a protective sleeve by the stirring sub-shaft 1, the stirring shaft 6, the shearing teeth 9, the suction hole 2, and the discharge hole 4. The blades of the passive stirring paddle 3 partially play the role of a movable baffle, which slightly suppresses the horizontal circulation and improves the mixing efficiency. The shearing teeth 9 on the stirring shaft 6 reduce the viscosity of the polymer fluid in the stirring sub-shaft 1 by shearing it, play a "lubricating" role, and reduce the stirring resistance. This embodiment achieves the purpose of improving the central mixing capacity, reducing the stirring resistance, saving energy, and improving the mixing efficiency through the above principles.

[0042] It should be noted that the technical solution of the utility model is directed to solving the mixing of materials with high polymer content and prone to climbing rod effect, and is not suitable for mixing other types of materials.

[0043] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only the specific implementation method of the utility model and is not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A drag-reducing stirring shaft with an adaptive anti-climbing rod, characterized in that: The invention comprises a stirring sub-shaft (1) and a stirring shaft (6); the stirring shaft (6) is rotatably connected to the stirring sub-shaft (1) via a bearing (7) provided at the top; a shearing structure is provided at the bottom of the stirring shaft (6); and a passive stirring paddle (3) is fixed to the outer side of the bottom of the stirring sub-shaft (1).

2. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 1 is characterized in that: The stirring auxiliary shaft (1) is a hollow cylindrical structure, and a limit block (5) for limiting the descent of the stirring auxiliary shaft (1) is provided on the outer side of the bottom of the stirring shaft (6).

3. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 2 is characterized in that: The diameter of the stirring auxiliary shaft (1) is smaller than the diameter of the limit block (5), and at least one limit block (5) is provided.

4. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 1, characterized in that: The shearing structure comprises shearing teeth (9), wherein the shearing teeth (9) are provided with at least three layers, namely, an upper layer, a lower layer and a middle layer; the upper layer and the lower layer are clockwise downward pressing shearing teeth, and the middle layer is shearing teeth with reverse upper and lower layers.

5. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 4, characterized in that: Each of the shear teeth (9) is rectangular, has an installation angle of 30-60 degrees, a width of 1-1.5 cm, and an installation gap that is less than 20% of the distance between the stirring auxiliary shaft (1) and the stirring shaft (6); and the regional distance between two adjacent layers is 1.5-2.0 m.

6. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 4, characterized in that: The shearing structure further comprises a screw paddle (8), the height of the screw paddle (8) being the same as the height of the shearing teeth (9); the ratio of the long diameter of the screw paddle (8) to the diameter of the screw paddle (8) itself is 1:1, and the length of the screw paddle (8) is 1-2.5 turns of the diameter of the screw paddle (8) itself.

7. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 1, characterized in that: The lower outer side of the stirring sub-shaft (1) is provided with a suction hole (2) and a discharge hole (4); the suction hole (2) is located at the upper part of the passive stirring paddle (3), and the discharge hole (4) is located at the lower part of the passive stirring paddle (3).

8. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 7, characterized in that: The suction holes (2) and the discharge holes (4) are distributed in a staggered manner. Two suction holes (2) and two discharge holes (4) are provided respectively, and the two suction holes (2) are distributed symmetrically, and the two discharge holes (4) are distributed symmetrically.

9. The drag-reducing stirring shaft of the adaptive anti-climbing rod according to claim 1, characterized in that: The stirring secondary shaft (1) adopts radial flow blades with an annular force bearing area.

10. The drag-reducing stirring shaft with an adaptive anti-climbing rod according to claim 1, characterized in that: The difference between the inner diameter of the stirring secondary shaft (1) and the diameter of the stirring shaft (6) is 2 to 2.5 centimeters; the blade length of the passive stirring paddle (3) is 1 / 3-1 / 4 of the container diameter, and the width-to-length ratio is 1 / 4-1 / 5.

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