Self-adaptive sealing device of roots pump and roots pump
By using a flexible sealing structure in the Roots pump, the wear problem between the shaft and the housing is solved, the pump's performance and lifespan are improved, adaptive sealing is achieved, and leakage is reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING TONGJIA HONGRUI TECHNOLOGY CO LTD
- Filing Date
- 2025-05-16
- Publication Date
- 2026-05-12
AI Technical Summary
In existing Roots pumps, the sealing ring between the shaft and the housing is prone to wear, leading to interstage leakage and affecting the pump's performance and lifespan.
The system employs a flexible sealing structure, including a fixed baffle and a flexible sealing layer. The flexible sealing layer has multiple cantilevered sections and flexible gaps, which can adapt to the deformation of the rotating shaft and reduce wear and leakage.
It improves the effective pumping speed of the Roots pump, extends the service life of the shaft, enhances sealing performance, and reduces maintenance cycles.
Smart Images
Figure CN224228861U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of vacuum pump technology, specifically relating to a Roots pump adaptive sealing device and a Roots pump. Background Technology
[0002] In a Roots vacuum pump, the two axes of the rotor are parallel to each other. The rotor is composed of impellers and shafts, with minute gaps between the impellers, and between the impellers and the casing and bearing plates, to prevent contact. Leakage in these gaps, especially between the shaft and the casing in a multi-stage rotor Roots pump, has a significant impact on the pump's performance. With the continuous development and improvement of Roots pump technology, the dynamic sealing problem of the shaft in high-performance Roots pumps has gradually become a bottleneck restricting pump performance.
[0003] Currently, multi-stage Roots pumps typically seal the rotors between each stage using sealing rings between the shaft and the housing. The minute deformation that occurs when the shaft rotates at high speed makes the sealing rings extremely prone to wear. The interstage leakage that occurs after the sealing rings wear out has a significant impact on the performance of the Roots pump.
[0004] To address the aforementioned problems, it is necessary to propose a well-designed and effective Roots pump adaptive sealing device and Roots pump. Utility Model Content
[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a Roots pump adaptive sealing device and a Roots pump.
[0006] One aspect of this utility model provides a self-adaptive sealing device for a Roots pump, which is sleeved between the shaft and the housing of the Roots pump for sealing the shaft and housing of the Roots pump. The device includes:
[0007] Two fixed baffles, which are annular in structure, are inserted through the rotating shaft and are arranged opposite each other in the axial direction of the rotating shaft;
[0008] A flexible sealing structure is sandwiched between the two fixed baffles. The flexible sealing structure is provided with multiple flexible gaps that penetrate its thickness, so that the end of the flexible sealing structure facing the rotating shaft forms multiple cantilever arms, and each cantilever arm has a preset gap between its end and the rotating shaft.
[0009] Optionally, each of the cantilever arms has a thrust surface at its end that is parallel to the outer wall surface of the pivot.
[0010] Optionally, the flexible sealing structure includes a low-pressure sealing layer and at least one high-pressure sealing layer superimposed on the low-pressure sealing layer; wherein,
[0011] The width of the thrust surface in the high-pressure sealing layer is consistent with the thickness of the cantilever.
[0012] Optionally, the cantilever in the low-pressure sealing layer is extended by a predetermined length along the axis of rotation toward the side away from the high-pressure sealing layer, so that a predetermined length of fitting gap is formed between the thrust surface in the low-pressure sealing layer and the rotating shaft.
[0013] Optionally, the distance from the thrust surface to the outer wall surface of the shaft in the high-pressure sealing layer is greater than the distance from the thrust surface to the shaft wall in the low-pressure sealing layer.
[0014] Optionally, the cantilever of the high-pressure sealing layer is distributed circumferentially along the axis of rotation in the flexible gap between two adjacent cantilever in the low-pressure sealing layer.
[0015] Optionally, the number of high-pressure sealing layers is multiple, and the multiple high-pressure sealing layers are stacked sequentially along the axial direction of the rotating shaft; wherein,
[0016] The flexible gaps between two adjacent high-pressure sealing layers are staggered.
[0017] Optionally, the plurality of flexible gaps extend from the end of the cantilever toward the radially outer direction of the flexible sealing structure, first in the positive radial direction and then inclined, with the inclined direction opposite to the rotation direction of the shaft.
[0018] Optionally, the device further includes a gasket sandwiched between the fixed baffle and the flexible sealing structure; wherein,
[0019] The gap between the inner circumferential wall of the gasket and the outer wall of the rotating shaft is greater than the preset gap between the end of the cantilever and the rotating shaft.
[0020] Another aspect of this utility model provides a Roots pump, including the Roots pump adaptive sealing device described above.
[0021] This invention relates to an adaptive sealing device for a Roots pump and the Roots pump itself. The sealing device is fitted onto the Roots pump shaft and is used for sealing between the shaft and the housing, particularly for sealing between the housing and the shaft of a multi-stage Roots pump. The flexible sealing structure of this device features multiple flexible gaps extending through its thickness, creating multiple cantilevered ends facing the shaft. When the shaft experiences radial runout, centrifugal deformation, or thermal expansion, the flexible gaps allow the flexible sealing structure to adapt to the shaft's deformation. Even if the shaft contacts the cantilever of the flexible sealing structure, the flexible design allows the shaft to continue operating efficiently without damaging the sealing structure. This sealing device reduces interstage leakage between the Roots pump shaft and housing, increases the effective pumping speed, and extends the shaft's service life. Furthermore, the highly adaptive flexible sealing structure is resistant to wear and damage, thus improving the overall lifespan of the Roots pump and extending its maintenance cycle. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of an adaptive sealing device for a Roots pump according to an embodiment of the present invention;
[0023] Figure 2 This is a schematic diagram of the structure of the low-pressure sealing layer according to another embodiment of the present invention;
[0024] Figure 3 This is a schematic diagram of the high-pressure sealing layer according to another embodiment of the present invention;
[0025] Figure 4 This is a cross-sectional view of an adaptive sealing device for a Roots pump according to another embodiment of the present invention;
[0026] Figure 5 This is a schematic diagram of the structure of the Roots pump adaptive sealing device at the installation position of the Roots pump, according to another embodiment of the present invention. Detailed Implementation
[0027] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0028] like Figures 1 to 4 As shown, one aspect of this utility model provides a self-adaptive sealing device 100 for a Roots pump, which is sleeved between the shaft and the housing of the Roots pump for sealing the shaft and housing, particularly for sealing the housing and shaft between the multiple chambers of a multi-stage Roots pump. The device includes two fixed baffles 110 and a flexible sealing structure 120.
[0029] The two fixed baffles 110 are annular structures, passing through the rotating shaft and positioned opposite each other along the axial direction of the rotating shaft.
[0030] A flexible sealing structure 120 is sandwiched between two fixed baffles 110, which fix the flexible sealing structure 120 in place. Further, the fixed baffles 110 can be regular annular thin sheet structures. The flexible sealing structure 120 is provided with multiple flexible gaps 121 extending through its thickness, so that the flexible sealing structure forms multiple cantilever 122 at one end facing the rotating shaft. Each cantilever 122 has a predetermined gap between its end and the rotating shaft.
[0031] It needs to be further explained that, such as Figure 1 As shown, in this embodiment, both the fixed baffle 110 and the flexible sealing structure 120 are annular, wherein the annulus is sleeved on the rotating shaft.
[0032] Due to the presence of the flexible gap 121, the flexible sealing structure 120 can adaptively deform to follow the deformation of the rotating shaft when the shaft deforms.
[0033] Specifically, when the shaft deforms, the deformed part of the shaft will transmit pressure to the flexible sealing structure 120. The pressure acts on the contact surface between the cantilever 122 of the flexible sealing structure 120 and the shaft. Since the flexible sealing structure 120 has a flexible gap 121, under the action of pressure, the flexible sealing structure 120 can form an interference fit or a clearance fit as needed, which can seal the airflow.
[0034] This utility model discloses an adaptive sealing device for a Roots pump. The flexible sealing structure features multiple flexible gaps extending through its thickness, creating multiple cantilevered arms at the end of the flexible sealing structure facing the shaft. When the shaft experiences radial runout, centrifugal deformation, or thermal expansion deformation, the flexible sealing structure adapts to the shaft's deformation due to the presence of these flexible gaps. Even if the shaft contacts the cantilever of the flexible sealing structure, the flexible design allows the shaft to continue operating efficiently without damaging the flexible sealing structure. This sealing device reduces interstage leakage between the Roots pump shaft and the housing, increases the effective pumping speed of the Roots pump, and extends the shaft's service life. Furthermore, the flexible sealing structure is highly adaptive, resistant to wear and damage, thus improving the overall lifespan of the Roots pump and extending its maintenance cycle.
[0035] For example, such as Figure 2 and Figure 3 As shown, each cantilever 122 has a thrust surface 123 at its end that is parallel to the shaft wall. There is a preset gap between the thrust surface 123 and the shaft wall.
[0036] Specifically, when the shaft deforms, it contacts the thrust surface 123 and transmits pressure to it. The shaft and the flexible sealing structure 120 are in surface contact, resulting in a large contact area and reducing shaft wear. Due to the presence of the flexible gap 121, an interference fit or clearance fit can be formed as needed under pressure, effectively sealing the airflow.
[0037] For example, such as Figure 4 As shown, the flexible sealing structure 120 includes a low-pressure sealing layer A and at least one high-pressure sealing layer B connected to the low-pressure sealing layer A. The low-pressure sealing layer A is located in the low-pressure zone of the Roots pump and performs low-pressure sealing; the high-pressure sealing layer B is located in the high-pressure zone of the Roots pump and performs high-pressure sealing. In this embodiment, the thickness of the low-pressure sealing layer A and the high-pressure sealing layer B is generally around 0.4 mm.
[0038] Among them, such as Figure 3 As shown, the width of the thrust surface 123 in the high-pressure sealing layer B is the same as the thickness of the cantilever 122. That is, the thrust surface 123 in the high-pressure sealing layer B is not extended. Because the installation space in the high-pressure zone of the Roots pump is small, the width of the thrust surface 123 in the high-pressure sealing layer B being the same as the thickness of the cantilever 122 is suitable for the high-pressure zone installation space. Here, the width of the thrust surface 123 refers to the distance between the two sides of the thrust surface 123 along the axial direction of the shaft, and the thickness of the cantilever 122 refers to the thickness of either the high-pressure sealing layer B or the low-pressure sealing layer A.
[0039] For example, such as Figure 2 As shown, in the low-pressure sealing layer A, the cantilever 122 extends a predetermined length along the axial direction of the rotating shaft towards the side opposite to the high-pressure sealing layer B, so that a predetermined length of fitting clearance is formed between the thrust surface 123 in the low-pressure sealing layer A and the rotating shaft. That is, the thrust surface 123 in the low-pressure sealing layer A extends a predetermined length along the axial direction of the rotating shaft towards the side opposite to the high-pressure sealing layer B. In this embodiment, the thrust surface 123 in the low-pressure sealing layer A extends 10mm along the axial direction of the rotating shaft. The extension length of the thrust surface 123 is not specifically limited in this embodiment and can be selected according to actual needs.
[0040] In this embodiment, the contact area between the thrust curved surface 123 in the low-pressure sealing layer A and the rotating shaft is larger, which further reduces the wear of the rotating shaft when it deforms.
[0041] For example, the distance from the thrust surface 123 in the high-pressure sealing layer B to the shaft wall is greater than the distance from the thrust surface 123 in the low-pressure sealing layer A to the shaft wall. In this embodiment, the distance from the thrust surface 123 in the low-pressure sealing layer A to the shaft wall is 0.03 mm, and the distance from the thrust surface 123 in the high-pressure sealing layer B to the shaft wall is greater than 0.03 mm, meaning the gap between the high-pressure sealing layer B and the shaft is greater than the gap between the low-pressure sealing layer A and the shaft. This embodiment does not specifically limit this distance; it can be selected according to actual needs.
[0042] In this embodiment, by setting the distance from the thrust surface 123 in the high-pressure sealing layer B and the low-pressure sealing layer A to the shaft wall, when the shaft deforms, the shaft will first contact the thrust surface 123 in the low-pressure sealing layer A. Since the thrust surface 123 in the low-pressure sealing layer A has a large area, the wear of the shaft can be reduced.
[0043] For example, such as Figure 4 As shown, the cantilever 122 of the high-pressure sealing layer B is distributed circumferentially along the axis of rotation in the flexible gap 121 between two adjacent cantilever in the low-pressure sealing layer A. That is, the flexible gap 121 in the high-pressure sealing layer B and the flexible gap 121 in the low-pressure sealing layer A are staggered.
[0044] In this embodiment, the cantilever 122 of the high-pressure sealing layer B is distributed circumferentially along the shaft in the flexible gap 121 between two adjacent cantilever in the low-pressure sealing layer A, which can prevent airflow from leaking from the flexible gap 121 and ensure the sealing between the shaft and the housing.
[0045] For example, there are multiple high-pressure sealing layers B, which are stacked sequentially along the axial direction of the rotating shaft. This embodiment does not specifically limit the number of high-pressure sealing layers B, and can select them according to actual needs. In this embodiment, two high-pressure sealing layers B are used as an example for explanation.
[0046] Among them, such as Figure 3 and Figure 4 As shown, the flexible gaps 121 of the two adjacent high-pressure sealing layers B are staggered to prevent airflow from leaking from the flexible gaps 121, further increasing the sealing between the shaft and the housing.
[0047] For example, multiple flexible gaps 121 extend radially from the end of the cantilever 122 toward the radially outer direction of the flexible sealing structure, then extend obliquely, with the oblique direction opposite to the rotation direction of the shaft. Specifically, as shown... Figure 2 and Figure 3As shown, in this embodiment, each flexible gap 121 in the low-pressure sealing layer A and the high-pressure sealing layer B extends radially outward from the end of the cantilever 122, first in a positive radial direction and then inclined. The multiple flexible gaps 121 in the low-pressure sealing layer A and the high-pressure sealing layer B are evenly spaced.
[0048] In this embodiment, multiple flexible gaps in the flexible sealing structure extend radially outward from the end of the cantilever, improving sealing reliability. When the cantilever end is subjected to airflow or axial force, the deformation of the flexible sealing structure is more uniform and stable, preventing one-sided deformation. The inclined distribution of multiple flexible gaps allows the thrust surface to undergo flexible deformation under stress, reducing wear.
[0049] For example, such as Figure 3 As shown, the flexible gap 121 includes an inclined portion 121a and an extension portion 121b connected to the inclined portion 121a and extending in the radial direction when close to the pivot. Specifically, as Figure 2 and Figure 3 As shown, in this embodiment, each flexible gap 121 in the low-pressure sealing layer A and the high-pressure sealing layer B includes an inclined portion 121a and an extension portion 121b. The inclined portion 121a may be distributed in a spiral shape.
[0050] like Figure 2 and Figure 3 As shown, in this embodiment, viewed from the low-pressure side, the flexible gap 121 is a gap inclined in a clockwise direction, such as... Figure 3 As shown, the arrow points in the direction of the rotation of the shaft, which is counterclockwise. That is, the tilt direction of the flexible gap 121 is opposite to the rotation direction of the shaft.
[0051] For example, the flexible gap 121 can also be a clockwise inclined curved gap, or a straight gap that radiates outwards, etc., which can be selected according to actual needs.
[0052] For example, such as Figure 1 and Figure 4 As shown, the fixed baffle 110 and the flexible sealing structure 120 are provided with a plurality of fixing holes 130 along their circumference. The Roots pump adaptive sealing device 100 also includes a plurality of fasteners, each fastener passing through its corresponding fixing hole 130 to fix the fixed baffle 110 and the flexible sealing structure 120.
[0053] Specifically, in this embodiment, the fixing hole 130 can be a rivet hole, and the fastener can be a rivet. The fixing baffle 110 and the flexible sealing structure 120 are riveted together by the rivet, and the entire Roots pump self-adaptive sealing device is fixed to the housing.
[0054] It should be noted that there are no specific restrictions on the type of fixing hole 130 and fasteners; they can be selected according to actual needs.
[0055] Other methods can be used to connect the fixed baffle 110 and the flexible sealing structure 120, such as bonding, pins, bolts, etc., as long as they can be fixed together.
[0056] like Figure 1 and Figure 4 As shown, the device also includes two gaskets 140, which are sandwiched between the fixed baffle 110 and the flexible sealing structure 120. Specifically, as... Figure 4 As shown, one gasket 140 is sandwiched between one fixed baffle 110 and the high-pressure sealing layer B, and the other gasket 140 is sandwiched between another fixed baffle 110 and the low-pressure sealing layer A.
[0057] For example, the gap between the inner circumferential wall of the gasket 140 and the outer wall of the shaft is greater than the preset gap between the end of the cantilever 122 and the shaft. Specifically, in this embodiment, the gasket 140 is also in the form of a ring-shaped thin sheet structure, wherein the inner ring of the gasket 140 is much larger than the inner ring of the low-pressure sealing layer A and the inner ring of the high-pressure sealing layer B.
[0058] In this embodiment, the gasket serves to fix the flexible sealing structure 120 while providing space for the axial deformation of the flexible sealing structure 120, thus preventing friction between the flexible sealing structure 120 and the cantilever 122.
[0059] For example, in this embodiment, the flexible sealing structure 120 can be made of nickel-based or cobalt-based high-temperature alloys. Nickel-based or cobalt-based high-temperature alloy materials have heat resistance, durability, good toughness, elasticity, and high mechanical properties.
[0060] It should be noted that the flexible sealing structure 120 can also be made of other flexible materials, which can be selected according to actual needs. This embodiment does not make specific limitations.
[0061] Another aspect of this utility model provides a Roots pump, including the Roots pump adaptive sealing device 100 described above. The specific structural features of the Roots pump adaptive sealing device 100 have been described in detail above and will not be repeated here.
[0062] Specifically, such as Figure 5 The diagram shows a Roots pump, including a housing 210, a rotor 220, and a shaft 230. The aforementioned Roots pump adaptive sealing device 100 is installed at position C. That is, the Roots pump adaptive sealing device 100 is sleeved on the Roots pump shaft, located between the shaft 230 and the housing 210, and is used for sealing between the Roots pump shaft 230 and the housing 210.
[0063] The Roots pump of this invention adopts the self-adaptive sealing device described above to achieve a seal between the Roots pump shaft and the housing, thereby improving the effective pumping speed of the Roots pump, extending the service life of the shaft, and achieving efficient and stable operation of the Roots pump.
[0064] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.
Claims
1. A self-adaptive sealing device for a Roots pump, sleeved between the shaft and housing of the Roots pump, for sealing the shaft and housing of the Roots pump, characterized in that, The device includes: Two fixed baffles, which are annular in structure, are inserted through the rotating shaft and are arranged opposite each other in the axial direction of the rotating shaft; A flexible sealing structure is sandwiched between the two fixed baffles. The flexible sealing structure is provided with multiple flexible gaps that penetrate its thickness, so that the end of the flexible sealing structure facing the rotating shaft forms multiple cantilever arms, and each cantilever arm has a preset gap between its end and the rotating shaft.
2. The apparatus according to claim 1, characterized in that, Each of the cantilever ends has a thrust surface parallel to the outer wall surface of the pivot.
3. The apparatus according to claim 2, characterized in that, The flexible sealing structure includes a low-pressure sealing layer and at least one high-pressure sealing layer superimposed on the low-pressure sealing layer; wherein... The width of the thrust surface in the high-pressure sealing layer is consistent with the thickness of the cantilever.
4. The apparatus according to claim 3, characterized in that, In the low-pressure sealing layer, the cantilever extends a predetermined length along the axis of the rotating shaft toward the side opposite to the high-pressure sealing layer, so that a predetermined length of fitting gap is formed between the thrust surface in the low-pressure sealing layer and the rotating shaft.
5. The apparatus according to claim 4, characterized in that, The distance from the thrust surface to the outer wall surface of the shaft in the high-pressure sealing layer is greater than the distance from the thrust surface to the shaft wall in the low-pressure sealing layer.
6. The apparatus according to claim 3, characterized in that, The cantilever of the high-pressure sealing layer is distributed circumferentially along the axis of rotation in the flexible gap between two adjacent cantilever in the low-pressure sealing layer.
7. The apparatus according to any one of claims 3 to 6, characterized in that, The number of high-pressure sealing layers is multiple, and the multiple high-pressure sealing layers are stacked sequentially along the axial direction of the rotating shaft; wherein... The flexible gaps between two adjacent high-pressure sealing layers are staggered.
8. The apparatus according to any one of claims 1 to 3, characterized in that, The multiple flexible gaps extend from the end of the cantilever toward the radially outer direction of the flexible sealing structure, first in the positive radial direction and then inclined, with the inclined direction opposite to the rotation direction of the shaft.
9. The apparatus according to any one of claims 1 to 3, characterized in that, The device further includes a gasket sandwiched between the fixed baffle and the flexible sealing structure; wherein... The gap between the inner circumferential wall of the gasket and the outer wall of the rotating shaft is greater than the preset gap between the end of the cantilever and the rotating shaft.
10. A Roots pump, characterized in that, Includes the Roots pump adaptive sealing device as described in any one of claims 1 to 9.