Modular bearing housing and blender and sand mixing tank comprising same

Abstract

The application relates to a modular bearing box and a mixer and a sand mixing tank comprising the same, and belongs to the technical field of sand mixing products. The modular bearing box comprises a bearing pair, a bearing inner sleeve and a bearing outer sleeve. The bearing pair is coaxially arranged with a stirring shaft. The bearing inner sleeve is arranged on the inner side of the bearing pair. The upper end of the bearing inner sleeve is used for connecting a motor, and the lower end is used for connecting the stirring shaft. The bearing outer sleeve is arranged on the outer side of the bearing pair. The upper end of the bearing outer sleeve is used for fixedly connecting a tank body, and the lower end is used for connecting a paddle fixing cylinder arranged outside the stirring shaft. The modular bearing box is arranged between the motor and the stirring shaft. When the bearing needs to be replaced or maintained, the modular bearing box can be directly disassembled for operation, so that the installation and maintenance of the bearing are more simple and convenient, the construction difficulty and cost are reduced, the stirring shaft and the paddle fixing cylinder can be assembled in a separated mode, the friction between the stirring shaft and the paddle fixing cylinder is reduced, and the stability and smoothness of stirring are improved.

Description

Technical Field

[0001] This invention belongs to the technical field of sand mixing products, and particularly relates to a modular bearing housing and a mixer and sand mixing tank containing therein. Background Technology

[0002] A sand mixer is a common piece of oilfield equipment used to prepare fracturing fluids. The agitator inside the sand mixer ensures the material system reaches a homogeneous state, promoting uniform reaction and heat transfer. The bearings of the sand mixer's agitator are a crucial component and require frequent maintenance and inspection. In current designs, such as... Figure 1 As shown, bearing 1' is installed between the stirring shaft 2' and the impeller fixing cylinder 3'. When maintaining the agitator bearing, it is necessary to first disconnect the agitator from the mixing tank, lift the agitator out of the mixing tank, and then disassemble the agitator before the bearing can be repaired or installed. Due to this design, the installation and maintenance of the bearing is very complex, requiring a large number of disassembly and installation operations. Moreover, the agitator is large in size, making lifting and disassembly difficult, which leads to high difficulty and cost in installation and maintenance.

[0003] Therefore, how to provide a bearing housing that can solve the problems of high difficulty and high cost in the installation and maintenance of bearings in current sand mixing tank agitators is an urgent technical problem to be solved. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a modular bearing housing and a mixer and sand mixing tank containing it. The modularly installed bearing housing achieves isolation between rotating and stationary components. At the same time, with a simple and clear structure, it solves the problems of high difficulty and cost in bearing installation and maintenance of current sand mixing tank mixers.

[0005] This invention provides a modular bearing housing, installed between the motor and the stirring shaft of a sand mixing tank agitator, and rotatably connected to the tank body of the sand mixing tank, comprising:

[0006] The bearing pair is coaxially arranged with the stirring shaft.

[0007] The bearing inner sleeve is fitted inside the bearing pair. The upper end of the bearing inner sleeve is used to connect the motor, and the lower end is used to connect the stirring shaft.

[0008] The bearing outer sleeve is fitted onto the outside of the bearing pair. The upper end of the bearing outer sleeve is used to fix and connect the tank body, and the lower end is used to connect the blade fixing cylinder fitted onto the outside of the stirring shaft.

[0009] This technical solution enables the transmission of torque between the motor and the stirring shaft, as well as the fixed connection between the tank and the impeller fixing cylinder, improving the stability and smoothness of the stirring. At the same time, the modular bearing housing is installed between the motor and the stirring shaft. When the bearing needs to be replaced or repaired, only the modular bearing housing needs to be disassembled, without disassembling the motor and stirring shaft or other structures. This makes the installation and maintenance of the bearing simpler and more convenient, reducing construction difficulty and cost.

[0010] In some embodiments, the outer wall of the bearing inner sleeve is provided with a first locking step, and the inner wall of the bearing outer sleeve is provided with a second locking step. The inner ring of the bearing pair is locked onto the first locking step, and the outer ring of the bearing pair is locked onto the second locking step. This technical solution can effectively prevent the bearing pair from slipping or falling off during rotation, making the installation of the bearing pair more reliable.

[0011] In some embodiments, a first bearing cap is installed at the upper end of the bearing pair, and the first bearing cap is connected to both the inner and outer bearing sleeves; a second bearing cap is installed at the lower end of the bearing pair, and the second bearing cap is connected to both the inner and outer bearing sleeves. This technical solution can protect the bearing pair from the intrusion of external impurities and can fix the position of the bearing pair, ensuring that the bearing pair will not fall off during rotation.

[0012] In some embodiments, the upper end of the first bearing cap is fixedly connected to the tank body via a bearing support flange, and the lower end of the second bearing cap is used to fixally connect to the blade fixing cylinder. This technical solution further realizes the fixed connection between the modular bearing housing and the fixed components, ensuring the normal operation of the modular bearing housing.

[0013] In some embodiments, the upper end of the bearing outer sleeve is provided with a third locking step, and the lower end is provided with a fourth locking step; the first bearing cap is locked into the third locking step to connect with the bearing outer sleeve, and the lower end of the first bearing cap abuts against the upper end of the bearing pair; the second bearing cap is locked into the fourth locking step to connect with the bearing outer sleeve, and the upper end of the second bearing cap abuts against the lower end of the bearing pair. This technical solution solves the problem of reliable fit between the first and second bearing caps and the bearing outer sleeve, and can further prevent the bearing pair from loosening or wobbling during rotation.

[0014] In some embodiments, skeleton oil seals are provided above and below the bearing pair. Each skeleton oil seal has an inner oil seal sleeve on the side near the bearing inner sleeve. The two inner oil seal sleeves are embedded in the bearing inner sleeve and tightly fitted with the bearing pair. This technical solution effectively prevents lubricant leakage through the skeleton oil seals, maintaining good lubrication of the bearing pair. Simultaneously, the inner oil seal sleeves protect the bearing inner sleeve from friction and wear caused by the skeleton oil seals.

[0015] In some embodiments, the bearing pair includes a first rolling bearing and a second rolling bearing, which are coaxially arranged, with the first rolling bearing positioned above the second rolling bearing. This technical solution, through two coaxially arranged rolling bearings, reduces radial runout and wear of the stirring shaft, making the operation of the stirring shaft more stable and reliable.

[0016] In some embodiments, the first rolling bearing is an angular contact ball bearing, and the second rolling bearing is a deep groove ball bearing. This technical solution can achieve load balance in both the axial and radial directions.

[0017] Furthermore, the present invention also provides a stirrer installed inside a sand mixing tank, comprising a motor, a stirring shaft, a blade fixing cylinder sleeved around the outer periphery of the stirring shaft, fixed blades connected to the blade fixing cylinder, and rotating blades connected to the lower end of the stirring shaft. It also includes the aforementioned modular bearing housing, which is installed between the motor and the stirring shaft. This technical solution achieves separate assembly of the stirring shaft and the blade fixing cylinder through the modular bearing housing, ensuring effective torque transmission and simplifying the installation and maintenance of the stirrer.

[0018] In addition, the present invention also provides a sand mixing tank, including a tank body, wherein the aforementioned agitator is installed inside the tank body. This technical solution reduces the operating cost of the sand mixing tank by using an agitator that is simple and easy to maintain.

[0019] Based on the above solution, a modular bearing housing for a sand mixing tank agitator in this embodiment of the invention can isolate the rotating parts from the fixed parts, thereby improving the stability and smoothness of the mixing; at the same time, the modular design of the bearing housing makes the installation and maintenance of the bearings simpler and more convenient, reducing construction difficulty and cost. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0021] Figure 1 A schematic diagram of the bearing installation structure of the agitator in a sand mixing tank in the prior art;

[0022] Figure 2 This is a schematic diagram of the modular bearing housing of the present invention;

[0023] Figure 3 This is a three-dimensional structural diagram of the modular bearing housing of the present invention;

[0024] Figure 4 This is a schematic diagram of the structure of the stirrer of the present invention;

[0025] Figure 5This is a schematic diagram of the sand mixing tank of the present invention.

[0026] In the picture:

[0027] 1' Bearing; 2' Agitator shaft; 3' Impeller retaining cylinder;

[0028] 1. Modular bearing housing; 2. Agitator; 3. Tank body;

[0029] 11. Bearing pair; 12. Bearing inner sleeve; 13. Bearing outer sleeve; 14. First bearing cap;

[0030] 15. Second bearing cap; 16. Oil seal skeleton; 17. Oil seal inner ring sleeve; 18. Grease injector;

[0031] 111. First rolling bearing; 112. Second rolling bearing; 121. First locking step;

[0032] 131. Second locking step; 132. Third locking step; 133. Fourth locking step;

[0033] 21. Motor; 22. Bearing support flange; 23. Agitator shaft; 24. Impeller fixing cylinder;

[0034] 25. Fix the blade; 26. Rotate the blade. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] like Figures 2-4 As shown, in one embodiment of a modular bearing housing of the present invention, the modular bearing housing 1 is installed between the motor 21 and the stirring shaft 23 of the sand mixing tank agitator 2, and is rotatably connected to the tank body 3 of the sand mixing tank. The modular bearing housing 1 includes a bearing pair 11, an inner bearing sleeve 12, and an outer bearing sleeve 13. The bearing pair 11 is coaxially arranged with the stirring shaft 23. The inner bearing sleeve 12 is sleeved on the inner side of the bearing pair 11, and the upper end of the inner bearing sleeve 12 is used to connect the motor 21, and the lower end is used to connect the stirring shaft 23. The outer bearing sleeve 13 is sleeved on the outer side of the bearing pair 11, and the upper end of the outer bearing sleeve 13 is used to fixally connect to the tank body 3, and the lower end is used to connect to the blade fixing cylinder 24 sleeved on the outside of the stirring shaft 23.

[0040] In the above illustrative embodiment, the modular bearing housing 1 enables the separate assembly of the stirring shaft 23 and the impeller fixing cylinder 24. The torque transmission from the motor 21 to the stirring shaft 23 is achieved through the inner bearing sleeve 12, and the fixed connection between the tank 3 and the impeller fixing cylinder 24 is achieved through the outer bearing sleeve 13. The bearing pair 11 is located between the inner bearing sleeve 12 and the outer bearing sleeve 13, achieving isolation between the inner bearing sleeve 12 and the outer bearing sleeve 13, further isolating the stirring shaft 23 and the impeller fixing cylinder 24, thereby reducing the friction between the stirring shaft 23 and the impeller fixing cylinder 24, while buffering the impact load and vibration on the stirring shaft 23, improving the stability and smoothness of stirring. At the same time, the modular bearing housing 1 is installed between the motor 21 and the stirring shaft 23. When the bearing needs to be replaced or repaired, only the modular bearing housing 1 needs to be disassembled, without disassembling the motor 21 and the stirring shaft 23 or other structures, thus making the installation and maintenance of the bearing simpler and more convenient, reducing construction difficulty and cost.

[0041] In some embodiments, such as Figure 2 As shown, the bearing pair 11 includes a first rolling bearing 111 and a second rolling bearing 112, which are coaxially arranged, with the first rolling bearing 111 positioned above the second rolling bearing 112. The two coaxial bearings balance the radial forces from the motor 21 and the stirring shaft 23 in both vertical directions, thereby reducing radial runout and wear of the stirring shaft 23. Furthermore, the use of rolling bearings with low friction coefficients and high transmission efficiency makes the operation of the stirring shaft 23 more stable and reliable.

[0042] Furthermore, such as Figure 2 As shown, the first rolling bearing 111 is an angular contact ball bearing, and the second rolling bearing 112 is a deep groove ball bearing. Angular contact ball bearings can withstand large axial loads and unidirectional radial loads, while deep groove ball bearings can withstand smaller axial loads and bidirectional radial loads. The combination of the two can achieve load balance in the axial and radial directions.

[0043] In some embodiments, such as Figure 2 As shown, the outer wall of the bearing inner sleeve 12 is provided with a first locking step 121, and the inner wall of the bearing outer sleeve 13 is provided with a second locking step 131. The inner ring of the bearing pair 11 (i.e., the aforementioned angular contact ball bearing and deep groove ball bearing) is locked onto the first locking step 121, and the outer ring of the bearing pair 11 is locked onto the second locking step 131. It should be noted that the outer wall of the bearing inner sleeve 12 is provided with first locking steps 121 on both the upper and lower sides. The inner ring of the angular contact ball bearing is locked onto the first locking step 121 located on the upper side, and the inner ring of the deep groove ball bearing is locked onto the first locking step 121 located on the lower side. The inner wall of the bearing outer sleeve 13 is provided with second locking steps 131 on both the upper and lower sides. The outer ring of the angular contact ball bearing is locked onto the second locking step 131 located on the upper side, and the outer ring of the deep groove ball bearing is locked onto the second locking step 131 located on the lower side. Thus, the bearing pair 11 is secured by the first locking step 121 and the second locking step 131, effectively preventing the bearing pair 11 from sliding or falling off during rotation, making the installation of the bearing pair 11 more reliable and improving the working stability and safety of the bearing pair 11.

[0044] In some embodiments, such as Figure 2 As shown, a first bearing cap 14 is installed at the upper end of the bearing pair 11 (here referring to the upper end of the angular contact ball bearing), and the first bearing cap 14 is connected to the inner bearing sleeve 12 and the outer bearing sleeve 13 respectively; a second bearing cap 15 is installed at the lower end of the bearing pair 11 (here referring to the lower end of the deep groove ball bearing), and the second bearing cap 15 is connected to the inner bearing sleeve 12 and the outer bearing sleeve 13 respectively. The first bearing cap 14 and the second bearing cap 15 protect the aforementioned angular contact ball bearing and deep groove ball bearing from the intrusion of external dust, moisture and impurities, and further ensure that the two bearings will not fall off during rotation, thus extending the service life of the bearings.

[0045] In some embodiments, such as Figure 4As shown, the upper end of the first bearing cap 14 is fixedly connected to the tank body 3 via the bearing support flange 22, and the lower end of the second bearing cap 15 is used to fixally connect to the blade fixing cylinder 24. By fixing the first bearing cap 14 to the bearing support flange 22 and the second bearing cap 15 to the blade fixing cylinder 24, the first bearing cap 14 and the second bearing cap 15 can be made more secure and stable, achieving a fixed connection between the tank body 3 and the blade fixing cylinder 24, and ensuring the normal operation of the modular bearing housing 1.

[0046] In some embodiments, such as Figure 2 As shown, the upper end of the bearing outer sleeve 13 is provided with a third locking step 132, and the lower end is provided with a fourth locking step 133; the first bearing cover 14 is locked in the third locking step 132 to connect with the bearing outer sleeve 13, and the lower end of the first bearing cover 14 abuts against the upper end of the bearing pair 11 (here referring to the upper end of the angular contact ball bearing); the second bearing cover 15 is locked in the fourth locking step 133 to connect with the bearing outer sleeve 13, and the upper end of the second bearing cover 15 abuts against the lower end of the bearing pair 11 (here referring to the lower end of the deep groove ball bearing). The third locking step 132 ensures a reliable fit between the first bearing cap 14 and the bearing outer sleeve 13, and the fourth locking step 133 ensures a reliable fit between the second bearing cap 15 and the bearing outer sleeve 13. The first bearing cap 14 can apply a certain preload to the angular contact ball bearing, and the second bearing cap 15 can apply a certain preload to the deep groove ball bearing, thereby further preventing the angular contact ball bearing and the deep groove ball bearing from loosening or wobble during rotation.

[0047] In some embodiments, such as Figure 2 As shown, both the upper and lower sides of the bearing pair 11 (referring to the upper side of the angular contact ball bearing and the lower side of the deep groove ball bearing) are provided with skeleton oil seals 16. The skeleton oil seals 16 prevent lubricant leakage and maintain good lubrication of the angular contact ball bearing and the deep groove ball bearing. Each of the two skeleton oil seals 16 has an inner oil seal sleeve 17 on the side near the bearing inner sleeve 12. The two inner oil seal sleeves 17 are embedded in the bearing inner sleeve 12 and are tightly fitted with the bearing pair 11 (referring to the angular contact ball bearing and the deep groove ball bearing, respectively). The inner oil seal sleeves 17 can protect the bearing inner sleeve 12 from friction and wear of the skeleton oil seals 16, extending the service life of the bearing inner sleeve 12. On the other hand, the tight fit between the inner oil seal sleeves 17 and the bearing pair 11 can prevent the bearing pair 11 from loosening during rotation.

[0048] In some embodiments, such as Figure 3As shown, the bearing outer sleeve 13 is equipped with a grease nipple 18, which penetrates the bearing outer sleeve 13 and communicates with the internal cavity formed by the first rolling bearing 111 (i.e., angular contact ball bearing) and the second rolling bearing 112 (i.e., deep groove ball bearing). Through the grease nipple 18, grease can be periodically replenished to the two bearings, maintaining good lubrication and extending their service life. Furthermore, the grease nipple 18 allows for easy removal and installation of grease, reducing maintenance costs and saving maintenance time.

[0049] Based on the modular bearing housing 1 described above, the present invention also provides a stirrer 2, such as... Figure 3 As shown, the agitator 2 is installed inside a sand mixing tank and includes a motor 21, a stirring shaft 23, a blade fixing cylinder 24 sleeved around the stirring shaft 23, a fixed blade 25 connected to the blade fixing cylinder 24, and a rotating blade 26 connected to the lower end of the stirring shaft 23. It also includes the aforementioned modular bearing housing 1, which is installed between the motor 21 and the stirring shaft 23. Specifically, the upper end of the bearing inner sleeve 12 of the modular bearing housing 1 is fixedly connected to the motor 21, and the lower end is fixedly connected to the stirring shaft 23. The lower end of the stirring shaft 23 is rotatably connected to the rotating blade 26. The upper end of the first bearing cap 14 is fixedly connected to the bearing support flange 22, and the lower end is fixedly connected to the blade fixing cylinder 24. The blade fixing cylinder 24 is fixedly connected to the fixed blade 25. Thus, the modular bearing housing 1 enables the separate assembly of the stirring shaft 23 and the blade fixing cylinder 24, making the installation and maintenance of the agitator 2 simpler and more convenient while ensuring transmission performance.

[0050] Specifically, such as Figure 4 As shown, the upper end of the bearing inner sleeve 12 of the modular bearing housing 1 is connected to the motor 21 of the agitator 2 via a connecting flange, and the lower end is connected to the impeller fixing cylinder 24 of the agitator 2 via a connecting flange. The force transmission process is: motor 21 → bearing inner sleeve 12 → agitator shaft 23 → rotating impeller 26. The torque generated when the motor 21 starts can drive the rotating impeller 26 to rotate through this transmission process, so as to realize the function of the agitator 2 in mixing the mixture. The first bearing cover 14 of the modular bearing housing 1 is fixedly connected to the tank body 3 of the sand mixing tank via the bearing support flange 22, and the second bearing cover 15 is connected to the impeller fixing cylinder 24 via the connecting flange. The connection achieves a fixed connection from tank 3 → bearing support flange 22 → first bearing cap 14 → bearing outer sleeve 13 → second bearing cap 15 → blade fixing cylinder 24 → fixed blade 25, that is, to achieve a fixed connection between the fixed blade 25 and tank 3, so as to counteract the counter-torque generated by the rotating blade 26 through the fixed blade 25, and maintain the stability and balance of the agitator 2; the bearing pair 11 inside the modular bearing housing 1, through the bearing inner sleeve 12 and bearing outer sleeve 13, avoids the friction between the agitator shaft 23 and the blade fixing cylinder 24, while buffering the impact load and vibration on the agitator shaft 23, improving the stability and smoothness of the agitation.

[0051] Based on the aforementioned agitator 2, the present invention also provides a sand mixing tank, such as... Figure 5 As shown, the sand mixing tank includes a tank body 3, inside which the aforementioned agitator 2 is installed. A motor 21 is fixedly mounted above the tank body 3, and a blade fixing cylinder 24 is fixedly mounted inside the tank body 3. The agitator shaft 23 is detachably connected to the output shaft of the motor 21 via a modular bearing housing 1 and is rotatably connected to the tank body 3. The inclusion of a modular bearing housing 1 in the agitator 2 simplifies the installation and maintenance of the bearings in the sand mixing tank agitator 2, thereby reducing the cost of bearing operation.

[0052] The modular bearing housing 1 in the above embodiments enables the separate assembly of the stirring shaft 23 and the impeller fixing cylinder 24 through modular installation. This is particularly suitable for applications where the stirring shaft 23 is of equal length to the stirrer 2. The modular bearing housing 1 occupies little space, facilitating installation, maintenance, and repair. Disassembly and repair can be completed within the mixing tank 3 without removing the stirrer 2, solving the current problem of having to disassemble the stirrer 2 before installing or maintaining the bearings. This reduces the difficulty of manual construction and thus saves on bearing usage costs. Other positive technical effects of the modular bearing housing 1 in the above embodiments also apply to the stirrer 2 and mixing tank containing the modular bearing housing 1, and will not be elaborated further here.

[0053] Through the description of several embodiments of the modular bearing housing and the agitator and sand mixing tank comprising therein, it can be seen that the embodiments of the modular bearing housing and the agitator and sand mixing tank comprising therein of the present invention have at least one or more of the following advantages:

[0054] 1. The modular bearing housing provided by the present invention designs the bearing as a modular bearing housing 1, which can be installed and disassembled separately, making the installation and maintenance of the bearing simple and convenient; and by designing two rolling bearings back to back, the modular bearing housing 1 achieves load balance in the axial and radial directions, making the operation more stable and reliable.

[0055] 2. The stirrer provided by the present invention achieves separate assembly of fixed parts and rotating parts through modular bearing housing 1, which reduces friction between fixed parts and rotating parts and improves the stability and smoothness of stirrer 2 operation;

[0056] 3. The mixing tank provided by the present invention achieves mixing of the mixture by means of a stirrer 2 with a modular bearing housing 1. The fixed part of the stirrer is connected to the tank body 3, the rotating part operates stably in the tank body 3, and the installation and maintenance of the bearing is very simple and convenient.

[0057] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A sand mixing tank, comprising a tank body and a stirrer, characterized in that, The stirrer includes: A motor is fixedly mounted on top of the tank, and the output shaft of the motor extends into the interior of the tank. A stirring shaft is located inside the tank. The upper end of the stirring shaft is detachably connected to the output shaft of the motor via a modular bearing housing, and the lower end of the stirring shaft is rotatably connected to the tank. A rotating impeller is connected to the lower end of the stirring shaft. The modular bearing housing includes a bearing pair, an inner bearing sleeve, and an outer bearing sleeve. The bearing pair is coaxially arranged with the stirring shaft. The inner bearing sleeve is fitted inside the bearing pair, with its upper end connected to the motor and its lower end connected to the stirring shaft. The outer bearing sleeve is fitted outside the bearing pair, with its upper end fixedly connected to the tank. A first bearing cap is installed on the upper end of the bearing pair, connecting to both the inner and outer bearing sleeves. A second bearing cap is installed on the lower end of the bearing pair, connecting to both the inner and outer bearing sleeves. The upper end of the first bearing cap is fixedly connected to the tank via a bearing support flange, and the lower end of the second bearing cap is fixedly connected to the impeller fixing cylinder. A blade fixing cylinder is sleeved on the outer periphery of the stirring shaft, and the upper end of the blade fixing cylinder is used to connect to the lower end of the bearing outer sleeve; a fixed blade is connected to the outside of the blade fixing cylinder.

2. The sand mixing tank according to claim 1, characterized in that, The bearing pair includes a first rolling bearing and a second rolling bearing, which are coaxially arranged, with the first rolling bearing positioned above the second rolling bearing. The first rolling bearing is an angular contact ball bearing, and the second rolling bearing is a deep groove ball bearing. The outer wall of the bearing inner sleeve is provided with first locking steps on both the upper and lower surfaces, and the inner wall of the bearing outer sleeve is provided with second locking steps on both the upper and lower surfaces. The inner and outer rings of the angular contact ball bearing are respectively locked onto the upper first and second locking steps, and the inner and outer rings of the deep groove ball bearing are respectively locked onto the lower first and second locking steps.

3. The sand mixing tank according to claim 1, characterized in that, The upper end of the bearing outer sleeve is provided with a third locking step, and the lower end is provided with a fourth locking step; the first bearing cover is locked in the third locking step to connect with the bearing outer sleeve, and the lower end of the first bearing cover abuts against the upper end of the bearing pair; the second bearing cover is locked in the fourth locking step to connect with the bearing outer sleeve, and the upper end of the second bearing cover abuts against the lower end of the bearing pair.

4. The sand mixing tank according to claim 1, characterized in that, Both the upper and lower sides of the bearing pair are provided with skeleton oil seals. Each of the two skeleton oil seals has an inner oil seal sleeve on the side near the inner sleeve of the bearing. The two inner oil seal sleeves are embedded in the inner sleeve of the bearing and are tightly fitted with the bearing pair respectively.

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