Upper sealing device of direct-drive screw pump

Abstract

The invention relates to the technical field of screw pump sealing, and discloses an upper sealing device of a direct-drive screw pump, which comprises a sealing seat body arranged at the top end of a motor main shaft; the wear-resistant seat is arranged at the top end of the central pipe, the central pipe is sleeved on the inner side of the motor main shaft, and the sealing seat body is arranged on the outer side of the wear-resistant seat; a bearing is arranged among the sealing assembly, the sealing seat body and the wear-resistant seat, the sealing assembly is arranged above the bearing, and the inner side and the outer side of the sealing assembly are in elastic sealing contact with the wear-resistant seat and the sealing seat body respectively; and the sealing cap hermetically sleeves the outer side of the top end of the motor main shaft. The inner side and the outer side of the sealing assembly are in elastic sealing contact with the wear-resisting seat and the sealing seat body correspondingly, so that the sealing assembly can make elastic contact with the wear-resisting seat, the center position is automatically adjusted, and eccentric wear is prevented. The concentricity between the sealing assembly and the central pipe is guaranteed, the service life of the sealing assembly is guaranteed, and liquid leakage is avoided.

Description

Technical Field

[0001] This invention relates to the field of screw pump sealing technology, and more specifically, to an upper sealing device for a direct-drive screw pump. Background Technology

[0002] Direct-drive screw pumps, as a type of high-efficiency and reliable positive displacement pump, are widely used in oil extraction, chemical transportation, and wastewater treatment. A typical direct-drive screw pump consists of a motor, sealing components, bearings, a central tube, and wellhead connection components (such as a wellhead sealer). Existing direct-drive screw pump oil production units typically use permanent magnet direct-drive motors. The seal above the motor is called the upper seal, and the seal below the motor is called the lower seal. Seal types typically include mechanical seals, packing seals, and multiple rubber ring seals. However, all of these sealing methods share a common problem: if the concentricity of the central tube deviates significantly, the seal's lifespan will decrease dramatically, leading to leakage of oil and other liquids.

[0003] Therefore, it is necessary to propose an upper sealing device for a direct-drive screw pump to at least partially solve the problems existing in the prior art. Summary of the Invention

[0004] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] To at least partially solve the above problems, the present invention provides an upper sealing device for a direct-drive screw pump, comprising: The sealing seat is located at the top of the motor spindle; A wear-resistant seat is set at the top of the central tube, which is sleeved on the inner side of the motor spindle, and the sealing seat body is set on the outer side of the wear-resistant seat. A sealing assembly is provided, wherein a bearing is provided between the sealing seat and the wear-resistant seat, and a sealing assembly is provided above the bearing, and the inner and outer sides of the sealing assembly are in elastic sealing contact with the wear-resistant seat and the sealing seat respectively. The sealing cap is fitted onto the outer top of the motor spindle.

[0006] Preferably, the sealing assembly includes a first seal and at least one second seal arranged sequentially, wherein the first seal is disposed above the bearing.

[0007] Preferably, the bottom inner side of the sealing seat is provided with a first annular groove corresponding to the bearing, the top of the first annular groove forms a stepped surface, and the bottom surface of the first seal is in contact with the stepped surface.

[0008] Preferably, the first seal includes: The first sealing seat is set on the stepped surface; The first sealing body is disposed in the first inner ring groove of the first sealing seat. The inner ring surface of the first sealing body is in elastic sealing contact with the outer ring surface of the wear-resistant seat. The side of the first inner ring groove is provided with a first sealing ring that contacts the first sealing body. The second sealing ring is disposed in the first outer ring groove of the first sealing seat, and the second sealing ring is in elastic sealing contact with the inner ring surface of the sealing seat body.

[0009] Preferably, the second seal includes: The second sealing seat is located above the first sealing element; The second sealing body is disposed in the second inner ring groove of the second sealing seat, and the inner ring surface of the second sealing body is in elastic sealing contact with the outer ring surface of the wear-resistant seat. The fourth sealing ring is disposed in the second outer ring groove of the second sealing seat, and the fourth sealing ring is in elastic sealing contact with the inner ring surface of the sealing seat body.

[0010] Preferably, the top surface of the sealing seat that contacts the sealing cap is provided with a second annular groove, and a fifth sealing ring that makes elastic sealing contact with the sealing cap is provided in the second annular groove; The outer side of the sealing seat is provided with a third outer ring groove, and a sixth sealing ring is provided in the third outer ring groove to elastically seal against the inner ring surface of the sealing cap. The inner side of the sealing cap is provided with a third inner ring groove, and a seventh sealing ring is provided in the third inner ring groove to elastically seal against the outer ring surface of the sealing seat.

[0011] Preferably, the bottom end of the wear-resistant seat is connected to the center tube, and a fourth outer ring groove is provided on the outer side of the bottom end of the wear-resistant seat. An eighth sealing ring is provided in the fourth outer ring groove, which is in elastic sealing contact with the inner ring surface of the center tube.

[0012] Preferably, the top of the sealing cap is provided with a groove, the bottom of the groove extends through the sealing cap, multiple sealing gaskets are provided in the groove, and a locking nut is provided at the top of the groove, so that the multiple sealing gaskets are pressed into the groove by the locking nut.

[0013] Preferably, the second sealing body includes: An internal elastic body has a V-shaped cross-section; wherein the internal elastic body includes a plurality of inner elastic pieces and a plurality of outer elastic pieces evenly arranged in the circumferential direction, the plurality of inner elastic pieces being disposed inside the plurality of outer elastic pieces, and the inner elastic pieces and outer elastic pieces being arranged alternately. The inner spring sheet has two connecting ends at its bottom, and the outer spring sheet has two connecting ends at its bottom. The two connecting ends of the inner spring sheet are respectively connected to the connecting ends of two adjacent outer spring sheets. An outer sealing body is fitted onto the outside of the inner elastic body, and the outer sealing body is disposed within the second inner annular groove; The top of the outer sealing body is open.

[0014] Preferably, it further includes: a snap-fit ​​member for connecting the first seal and the second seal, or for connecting two second seals; the snap-fit ​​member includes: At least two elastic locking heads are provided on the first annular plate. Each elastic locking head includes a guide portion, a locking portion, and an elastic deformation portion arranged in sequence. The elastic deformation portion is connected to the first annular plate. The guide portion forms an inclined surface on the inner ring side, the locking portion forms a locking groove on the inner ring side, and the elastic deformation portion forms an arc-shaped recess on the outer ring side. A limiting part is provided on the second annular plate, the cross-section of the second annular plate is L-shaped, and the limiting part is radially engaged with the slot; the limiting part is a retaining ring or a retaining block corresponding to the elastic retaining head; The first and second sealing members have a first mounting groove on their top surfaces for mounting the first annular plate, and the second sealing member has a second mounting groove on its bottom surface for mounting the second annular plate.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The upper sealing device of the direct-drive screw pump described in this invention has an inner and outer side of the sealing component that elastically seals with the wear-resistant seat and the sealing seat body, respectively. This allows the sealing component to elastically contact the wear-resistant seat, automatically adjust its center position, and prevent uneven wear. Furthermore, the end of the central tube furthest from the wear-resistant seat is a fixed end. The sealing component forms an elastic abutment against the wear-resistant seat connected to the top of the central tube, ensuring the concentricity between the sealing component and the central tube. This prevents the wear-resistant seat from causing significant uneven wear force on the sealing component, ensuring the service life of the sealing component and preventing liquid leakage.

[0016] The upper sealing device of the direct-drive screw pump described in this invention, other advantages, objectives and features of this invention will be apparent in part from the following description, and in part will be understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the internal structure of the direct-drive screw pump described in this invention; Figure 2 This is a schematic diagram of the upper sealing device of the direct-drive screw pump described in this invention; Figure 3This is a detailed structural diagram of the upper sealing device of the direct-drive screw pump described in this invention; Figure 4 This is a schematic diagram of the structure of the second sealing body in the upper sealing device of the direct-drive screw pump of the present invention; Figure 5 This is an exploded structural diagram of the second seal in the upper sealing device of the direct-drive screw pump of the present invention; Figure 6 This is a schematic diagram of the internal elastic body in the upper sealing device of the direct-drive screw pump described in this invention; Figure 7 This is an exploded structural diagram of two adjacent second seals in the upper sealing device of the direct-drive screw pump described in this invention. Figure 8 This is a schematic diagram of the installation structure of two adjacent second seals in the upper sealing device of the direct-drive screw pump described in this invention. Figure 9 This is a schematic diagram of the structure of the upper sealing device of the direct-drive screw pump described in this invention when the elastic clamp and the limiting part are not engaged. Figure 10 This is a schematic diagram of the structure of the first annular plate and the elastic clamp in the upper sealing device of the direct-drive screw pump described in this invention; Figure 11 This is a schematic diagram of the structure of the second annular plate and the limiting part in the upper sealing device of the direct drive screw pump described in this invention.

[0018] 1 is a sealing seat body, 11 is a first annular groove, 12 is a second annular groove, 13 is a bearing, 2 is a wear-resistant seat, 3 is a sealing cap, 31 is a multi-layer sealing gasket, 4 is a first sealing element, 41 is a first sealing seat, 42 is a first sealing body, 411 is a first inner annular groove, 412 is a first outer annular groove, 43 is a first sealing ring, 44 is a second sealing ring, 45 is a first mounting groove, 5 is a second sealing element, 51 is a second sealing seat, 511 is a second inner annular groove, 512 is a second outer annular groove, 52 is a second sealing body, 521 is an internal elastic body, and 522 is an internal spring sheet. 523 is the outer spring sheet, 524 is the outer sealing body, 54 is the fourth sealing ring, 55 is the second mounting groove, 6 is the fifth sealing ring, 7 is the sixth sealing ring, 8 is the seventh sealing ring, 9 is the eighth sealing ring, 10 is the locking nut, 20 is the first annular plate, 30 is the elastic clamp, 301 is the guide part, 302 is the snap-fit ​​part, 303 is the elastic deformation part, 304 is the slot, 305 is the arc-shaped recess, 40 is the second annular plate, 50 is the limiting part, 60 is the motor spindle, 70 is the central tube, 80 is the rain cover, 90 is the motor body, and 100 is the well sealer. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0020] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0021] like Figures 1-3 As shown, the present invention provides an upper sealing device for a direct-drive screw pump, comprising: The sealing seat 1 is located at the top of the motor spindle 60; Wear-resistant seat 2 is set at the top of the central tube 70, the central tube 70 is sleeved on the inner side of the motor spindle 60, and the sealing seat 1 is set on the outer side of the wear-resistant seat 2. A sealing assembly is provided, wherein a bearing 13 is provided between the sealing seat 1 and the wear-resistant seat 2, and a sealing assembly is provided above the bearing 13. The inner and outer sides of the sealing assembly are in elastic sealing contact with the wear-resistant seat 2 and the sealing seat 1, respectively. The sealing cap 3 is fitted onto the outer side of the top end of the motor spindle 60.

[0022] The wear-resistant seat 2 is screwed onto the top of the central tube 70 by a thread.

[0023] The direct-drive screw pump includes: an upper sealing device, a rain cover 80, a motor body 90, a central tube 70, and a well sealer 100. The rain cover 80 is provided on the outside of the motor spindle 60 below the sealing cap 3. The motor spindle 60 is driven by the motor body 90. The upper sealing device is completely fitted onto the motor spindle 60. The central tube 70 is fixed to the lower bearing chamber of the motor body 90 by screws. The bottom of the central tube 70 is inserted into the well sealer 100, and the upper end of the central tube 70 is connected to the upper sealing device. The motor body 90 and the well sealer 100 are fixed by bolts.

[0024] The bearing 13 below the sealing assembly is a deep groove ball bearing. The bearing 13 can ensure the concentricity of the wear-resistant seat 2 and the sealing assembly. In addition, the inner and outer sides of the sealing assembly are in elastic sealing contact with the wear-resistant seat 2 and the sealing seat body 1, respectively, so that the sealing assembly can elastically contact the wear-resistant seat 2, automatically adjust the center position, and prevent uneven wear. Furthermore, the end of the central tube 70 away from the wear-resistant seat 2 is a fixed end. The sealing assembly forms an elastic abutment against the wear-resistant seat 2 connected to the top of the central tube 70, ensuring the concentricity between the sealing assembly and the central tube 70. This prevents the wear-resistant seat 2 from causing a large uneven wear force on the sealing assembly, ensuring the service life of the sealing assembly and preventing liquid leakage.

[0025] like Figure 2As shown, in one embodiment, the sealing assembly includes a first seal 4 and at least one second seal 5 arranged sequentially, the first seal 4 being disposed above the bearing 13.

[0026] The sealing assembly employs a multi-stage sealing method, which can extend the life of the seal and reduce the probability of liquid leakage.

[0027] like Figure 2 As shown, in one embodiment, the bottom inner side of the sealing seat 1 is provided with a first annular groove 11 corresponding to the bearing 13, the top of the first annular groove 11 forms a stepped surface, and the bottom surface of the first seal 4 contacts the stepped surface.

[0028] The first seal 4 does not contact the bearing 13, and the second seal 5 is positioned above the first seal 4.

[0029] like Figure 3 As shown, in one embodiment, the first seal 4 includes: The first sealing seat 41 is disposed on the stepped surface; The first sealing body 42 is disposed in the first inner ring groove 411 of the first sealing seat 41. The inner ring surface of the first sealing body 42 is in elastic sealing contact with the outer ring surface of the wear-resistant seat 2. The side of the first inner ring groove 411 is provided with a first sealing ring 43 that contacts the first sealing body 42. The second sealing ring 44 is disposed in the first outer ring groove 412 of the first sealing seat 41, and the second sealing ring 44 is in elastic sealing contact with the inner ring surface of the sealing seat body 1.

[0030] Both the first sealing ring 43 and the second sealing ring 44 can be O-rings. The first sealing seat 41 can be a PTFE oil seal seat, and the first sealing body 42 can be a PTFE oil seal, also known as a polytetrafluoroethylene oil seal. It has excellent chemical corrosion resistance and can withstand a variety of strong acids, strong alkalis, organic solvents and corrosive media. It can withstand extremely high temperatures and usually has good sealing performance between -200℃ and +260℃. In addition, the PTFE oil seal has an extremely low coefficient of friction and good self-lubricating properties, which enables the first sealing element 4 to reduce energy consumption, reduce wear caused by friction, and extend the sealing life during operation.

[0031] like Figure 3 As shown, in one embodiment, the second seal 5 includes: The second sealing seat 51 is disposed above the first sealing element 4; The second sealing body 52 is disposed in the second inner ring groove 511 of the second sealing seat 51, and the inner ring surface of the second sealing body 52 is in elastic sealing contact with the outer ring surface of the wear-resistant seat 2. The fourth sealing ring 54 is disposed in the second outer ring groove 512 of the second sealing seat 51, and the fourth sealing ring 54 is in elastic sealing contact with the inner ring surface of the sealing seat body 1.

[0032] The fourth sealing ring 54 can be an O-ring, the second sealing seat 51 can be a plug seal seat, and the second sealing body 52 can be a plug seal. A plug seal is a high-performance seal with a special spring installed inside a U-shaped Teflon. It is suitable for high-temperature and corrosive environments, and has a low coefficient of friction, stable sealing contact pressure, strong wear resistance, can tolerate large radial deviations, has a long service life, and can guarantee sealing performance.

[0033] like Figure 3 As shown, in one embodiment, the top surface of the sealing seat 1 that contacts the sealing cap 3 is provided with a second annular groove 12, and a fifth sealing ring 6 that is in elastic sealing contact with the sealing cap 3 is provided in the second annular groove 12. The outer side of the sealing seat 1 is provided with a third outer ring groove, and the third outer ring groove is provided with a sixth sealing ring 7 that is in elastic sealing contact with the inner ring surface of the sealing cap 3. The inner side of the sealing cap 3 is provided with a third inner ring groove, and a seventh sealing ring 8 is provided in the third inner ring groove to elastically seal against the outer ring surface of the sealing seat 1.

[0034] The fifth sealing ring 6, the sixth sealing ring 7, and the seventh sealing ring 8 are used to ensure a static seal between the sealing seat 1 and the sealing cap 3, and to ensure the sealing performance of the sealing cap 3 during installation.

[0035] like Figure 3 As shown, in one embodiment, the bottom end of the wear-resistant seat 2 is connected to the center tube 70, and a fourth outer ring groove is provided on the outer side of the bottom end of the wear-resistant seat 2. An eighth sealing ring 9 is provided in the fourth outer ring groove, which is in elastic sealing contact with the inner ring surface of the center tube 70.

[0036] The bottom end of the wear-resistant seat 2 can be inserted into the central tube 70 and threadedly connected to the central tube 70. An eighth sealing ring 9 is set above the threaded connection. The eighth sealing ring 9 can be an O-ring to ensure the sealing of the connection and to form a pre-tightening force on the connection between the central tube 70 and the wear-resistant seat 2, ensuring the stability of the connection.

[0037] like Figure 3 As shown, in one embodiment, the top end of the sealing cap 3 is provided with a groove, the bottom end of the groove is provided through the sealing cap 3, multiple sealing gaskets 31 are provided in the groove, and the top end of the groove is provided with a locking nut 10, which presses the multiple sealing gaskets 31 into the groove.

[0038] The multi-layer sealing gasket 31 includes at least one first flat gasket, at least one V-shaped gasket, and at least one second flat gasket arranged in sequence. During installation, the multi-layer sealing gasket 31 is placed into the groove in sequence, and then the locking nut 10 is threadedly connected to the sealing cap 3 to press the multi-layer sealing gasket 31 tight and seal the top of the sealing cap 3.

[0039] In one embodiment, another structure for the second sealing body 52 is also provided, such as... Figures 4-6 As shown, the second sealing body 52 includes: The internal elastic body 521 has a V-shaped cross section; wherein, the internal elastic body 521 includes a plurality of inner elastic pieces 522 and a plurality of outer elastic pieces 523 evenly arranged in the circumferential direction, the plurality of inner elastic pieces 522 are disposed inside the plurality of outer elastic pieces 523, and the inner elastic pieces 522 and the outer elastic pieces 523 are arranged alternately. The inner spring piece 522 has two connecting ends at its bottom, and the outer spring piece 523 has two connecting ends at its bottom. The two connecting ends of the inner spring piece 522 are respectively connected to the connecting ends of two adjacent outer spring pieces 523. An outer sealing body 524 is sleeved on the outside of the inner elastic body 521, and the outer sealing body 524 is disposed in the second inner annular groove 511; The top of the outer sealing body 524 is open.

[0040] After being subjected to radial compression, the inner spring sheet 522 and the outer spring sheet 523 store elastic deformation energy and form an elastic force on the outer sealing body 524, thereby enabling the outer sealing body 524 to form a seal on the parts in contact with it; the outer sealing body 524 is made of Teflon material. The top dimensions of the inner spring sheet 522 and the outer spring sheet 523 are smaller than their bottom dimensions. The main elastic deformation areas of the inner spring sheet 522 and the outer spring sheet 523 are at their connection. When the outer sealing body 524 wears out after long-term use, the inner spring sheet 522 and the outer spring sheet 523 can compensate for the wear through their elastic recovery, so that the outer sealing body 524 can always be in close contact with the wear-resistant seat 2. In addition, the elastic force of the inner elastic body 521 can form a large radial support force on the wear-resistant seat 2, ensuring the concentricity of the wear-resistant seat 2 and the sealing assembly, avoiding uneven wear, especially avoiding frictional contact between the wear-resistant seat 2 and the first sealing seat 41 and the second sealing seat 51, thus ensuring the service life of the sealing assembly.

[0041] The first seal 4 and the second seal 5, as well as the two second seals 5, can be installed in contact only, or in a snap-fit ​​manner. like Figures 7-11As shown, in one embodiment, it further includes: a snap-fit ​​member for connecting the first seal 4 and the second seal 5, or for connecting two second seals 5; the snap-fit ​​member includes: At least two elastic locking heads 30 are disposed on the first annular plate 20. Each elastic locking head 30 includes a guide portion 301, a locking portion 302, and an elastic deformation portion 303 disposed sequentially. The elastic deformation portion 303 is connected to the first annular plate 20. The guide portion 301 forms an inclined surface on the inner ring side, the locking portion 302 forms a locking groove 304 on the inner ring side, and the elastic deformation portion 303 forms an arc-shaped recess 305 on the outer ring side. A limiting part 50 is provided on the second annular plate 40, the cross section of the second annular plate 40 is L-shaped, and the limiting part 50 is radially engaged with the slot 304; the limiting part 50 is a retaining ring or a retaining block corresponding to the elastic retaining head 30; The top surface of the first sealing member 4 and the second sealing member 5 is provided with a first mounting groove 45 for mounting the first annular plate 20, and the bottom surface of the second sealing member 5 is provided with a second mounting groove 55 for mounting the second annular plate 40.

[0042] The first annular plate 20 is fixed to the first mounting groove 45 by screws, and the second annular plate 40 is fixed to the second mounting groove 55 by screws.

[0043] When installing the first seal 4 and the second seal 5, they can be placed sequentially inside the sealing seat 1. At this time, the elastic locking head 30 and the limiting part 50 are as follows: Figure 9 The overlapping state is shown, and then pressure is applied downward to the first seal 4 and the second seal 5 in the sealing seat 1, so that the limiting part 50 can move downward along the guide part 301 and engage in the slot 304 of the engaging part 302, thereby realizing the installation and fixation of the two adjacent seals. The arc-shaped recess 305 at the elastic deformation portion 303 of the elastic clamp 30 ensures that the elastic clamp 30 has a certain deformation capacity. This not only ensures the locking stability of the two adjacent seals, but also allows the two adjacent seals to make slight radial movements. Thus, when there is a deviation between the axis of the wear-resistant seat 2 and the axis of the sealing assembly, the deviation between the axis of each seal and the axis of the wear-resistant seat 2 is different, resulting in different forces on each seal. This allows each seal to adapt to the movement of the wear-resistant seat 2 and ensures sealing performance. In addition, the elastic recovery function of the elastic clamp 30 can promote the concentricity of the wear-resistant seat 2 and the sealing assembly, further preventing uneven wear.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the present invention, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A top sealing device for a direct-drive screw pump, characterized in that, include: A sealing seat (1) is set at the top of the motor spindle (60); Wear-resistant seat (2) is set at the top of the central tube (70), the central tube (70) is sleeved on the inner side of the motor spindle (60), and the sealing seat body (1) is set on the outer side of the wear-resistant seat (2); A sealing assembly is provided between the sealing seat (1) and the wear-resistant seat (2), and a sealing assembly is provided above the bearing (13). The inner and outer sides of the sealing assembly are in elastic sealing contact with the wear-resistant seat (2) and the sealing seat (1), respectively. The sealing cap (3) is fitted onto the outer side of the top end of the motor spindle (60).

2. The upper sealing device of the direct-drive screw pump according to claim 1, characterized in that, The sealing assembly includes a first seal (4) and at least one second seal (5) arranged in sequence, wherein the first seal (4) is located above the bearing (13).

3. The upper sealing device of the direct-drive screw pump according to claim 2, characterized in that, The bottom inner side of the sealing seat (1) is provided with a first annular groove (11) corresponding to the bearing (13), the top of the first annular groove (11) forms a stepped surface, and the bottom surface of the first sealing element (4) contacts the stepped surface.

4. The upper sealing device of the direct-drive screw pump according to claim 3, characterized in that, The first seal (4) includes: The first sealing seat (41) is set on the step surface; The first sealing body (42) is disposed in the first inner ring groove (411) of the first sealing seat (41). The inner ring surface of the first sealing body (42) is in elastic sealing contact with the outer ring surface of the wear-resistant seat (2). The side of the first inner ring groove (411) is provided with a first sealing ring (43) that contacts the first sealing body (42). The second sealing ring (44) is disposed in the first outer ring groove (412) of the first sealing seat (41), and the second sealing ring (44) is in elastic sealing contact with the inner ring surface of the sealing seat body (1).

5. The upper sealing device of the direct-drive screw pump according to claim 3, characterized in that, The second seal (5) includes: The second sealing seat (51) is disposed above the first sealing element (4); The second sealing body (52) is disposed in the second inner ring groove (511) of the second sealing seat (51), and the inner ring surface of the second sealing body (52) is in elastic sealing contact with the outer ring surface of the wear-resistant seat (2). The fourth sealing ring (54) is disposed in the second outer ring groove (512) of the second sealing seat (51), and the fourth sealing ring (54) is in elastic sealing contact with the inner ring surface of the sealing seat body (1).

6. The upper sealing device of the direct-drive screw pump according to claim 1, characterized in that, The top surface of the sealing seat (1) that contacts the sealing cap (3) is provided with a second annular groove (12), and a fifth sealing ring (6) that is in elastic sealing contact with the sealing cap (3) is provided in the second annular groove (12). The outer side of the sealing seat (1) is provided with a third outer ring groove, and the third outer ring groove is provided with a sixth sealing ring (7) that is in elastic sealing contact with the inner ring surface of the sealing cap (3). The inner side of the sealing cap (3) is provided with a third inner ring groove, and the third inner ring groove is provided with a seventh sealing ring (8) that is in elastic sealing contact with the outer ring surface of the sealing seat (1).

7. The upper sealing device of the direct-drive screw pump according to claim 1, characterized in that, The bottom end of the wear-resistant seat (2) is connected to the center tube (70). The outer side of the bottom end of the wear-resistant seat (2) is provided with a fourth outer ring groove. The fourth outer ring groove is provided with an eighth sealing ring (9) that is in elastic sealing contact with the inner ring surface of the center tube (70).

8. The upper sealing device of the direct-drive screw pump according to claim 1, characterized in that, The top of the sealing cap (3) is provided with a groove, the bottom of the groove is provided through the sealing cap (3), the groove is provided with multiple layers of sealing gaskets (31), and the top of the groove is provided with a locking nut (10). The multiple layers of sealing gaskets (31) are pressed into the groove by the locking nut (10).

9. The upper sealing device of the direct-drive screw pump according to claim 5, characterized in that, The second sealing body (52) includes: An inner elastic body (521) has a V-shaped cross section; wherein, the inner elastic body (521) includes a plurality of inner elastic pieces (522) and a plurality of outer elastic pieces (523) evenly arranged in the circumferential direction, the plurality of inner elastic pieces (522) are disposed on the inner side of the plurality of outer elastic pieces (523), and the inner elastic pieces (522) and the outer elastic pieces (523) are arranged alternately; An outer sealing body (524) is fitted onto the outside of an inner elastic body (521), and the outer sealing body (524) is disposed within a second inner annular groove (511).

10. The upper sealing device of the direct-drive screw pump according to claim 2, characterized in that, Also includes: A snap-fit ​​connector for connecting the first seal (4) and the second seal (5) or for connecting two second seals (5); the snap-fit ​​connector includes: At least two elastic clips (30) are provided on the first annular plate (20). Each elastic clip (30) includes a guide portion (301), a snap-fit ​​portion (302), and an elastic deformation portion (303) arranged in sequence. The elastic deformation portion (303) is connected to the first annular plate (20). The guide portion (301) forms an inclined surface on the inner ring side, the snap-fit ​​portion (302) forms a groove (304) on the inner ring side, and the elastic deformation portion (303) forms an arc-shaped recess (305) on the outer ring side. A limiting part (50) is provided on the second annular plate (40), the cross section of the second annular plate (40) is L-shaped, and the limiting part (50) is radially engaged with the slot (304); the limiting part (50) is a retaining ring or a retaining block corresponding to the elastic retaining head (30); The top surfaces of the first sealing member (4) and the second sealing member (5) are provided with a first mounting groove (45) for mounting the first annular plate (20), and the bottom surface of the second sealing member (5) is provided with a second mounting groove (55) for mounting the second annular plate (40).

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