Roots screw vacuum system with cooling device
Patent Information
- Application Number
- CN202522456724.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-09-29
- Estimated Expiration
- 2035-11-19
AI Technical Summary
过高的气体温度会引发一系列问题，首先，它会引起泵体内部零件的热膨胀，从而危及关键的微小运行间隙，增加摩擦甚至卡滞的风险；其次，高温会使气体分子运动加剧，返流率增加，直接制约系统极限真空度的提升
[0016]本实用新型通过设置在泵腔进气端的冷却源，利用交叉曲线型流道将制冷腔分隔为周向包覆的液冷区与内部气流区，形成三明治夹层式换热结构，使得进气气流被引导产生双股对向涡旋，此动态的涡旋相互作用与静态的三明治夹层式换热结构相互协同，共同实现了对气体介质高效、均匀的强化制冷，从而从源头有效降低了进入泵腔的气体温度，解决了因罗茨螺杆真空泵定子与转子之间微米级间隙导致气体温升所带来的真空度下降及运行可靠性问题。
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Figure CN224813985U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of vacuum pump technology, and in particular to a Roots screw vacuum system with a cooling device. Background Technology
[0002] A Roots screw vacuum system is a dry vacuum generating device that combines the advantages of Roots pumps and screw pumps. It achieves continuous suction and compression of gas through a pair of meshing helical rotors rotating synchronously at high speed in a non-contact manner within the pump chamber. To ensure high efficiency and prevent backflow, a precise micron-level gap must be maintained between the rotor and the pump chamber stator.
[0003] In a Roots screw vacuum system, to prevent backflow of the pumped gas and maintain a high vacuum, an extremely small, micrometer-level gap must be maintained between the stator and rotor. This structural feature leads to a significant temperature rise during gas compression and discharge. Excessively high gas temperatures can cause a series of problems. First, it can cause thermal expansion of internal pump components, thereby jeopardizing critical micro-operating gaps and increasing the risk of friction or even jamming. Second, high temperatures intensify gas molecule movement, increasing the backflow rate and directly limiting the improvement of the system's ultimate vacuum. Utility Model Content
[0004] To address the shortcomings of existing technologies, this invention provides a Roots screw vacuum system with a cooling device, which solves the technical problems mentioned in the background section.
[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a Roots screw vacuum system with a cooling device, comprising;
[0006] Pump chamber;
[0007] A cooling source is disposed at the air inlet end of the pump chamber, which is axially aligned with the air outlet end of the pump chamber. The cooling source includes:
[0008] A columnar hollow shell, the interior of which forms a refrigeration chamber for the flow of liquid cooling medium;
[0009] Two intersecting curved flow channels, located inside the hollow shell and extending axially, divide the cooling cavity into a circumferentially enclosed liquid cooling zone and an internal airflow zone, forming an axial sandwich-type heat exchange structure.
[0010] The two intersecting curved flow channels guide the intake airflow to generate two opposing vortices. The interaction of the two opposing vortices, together with the sandwich-type heat exchange structure, constitutes enhanced cooling of the gas medium.
[0011] Preferably, the axial projections of the two intersecting curved flow channels form a continuous X shape on a plane perpendicular to the pump cavity axis, with an intersection angle of 50°-130°.
[0012] Preferably, the diameter of the continuous X-shaped flow channel of the two intersecting curved flow channels increases in a gradient along the gas flow direction.
[0013] Preferably, the two intersecting curved flow channels form a collision and fusion region of two opposing vortices, which coincides axially with the section in the sandwich heat exchange structure where the liquid cooling zone is most fully covered.
[0014] Preferably, the two intersecting curved flow channels are continuously X-shaped flow channels that are intersected and merged at least three times in the axial direction.
[0015] By employing the above technical solution, this utility model provides a Roots screw vacuum system with a cooling device, which has at least the following beneficial effects:
[0016] This invention utilizes a cooling source located at the inlet of the pump chamber. By employing a cross-curved flow channel, the cooling chamber is divided into a circumferentially enclosed liquid-cooled zone and an internal airflow zone, forming a sandwich-type heat exchange structure. This guides the intake airflow to generate two opposing vortices. The dynamic interaction of these vortices, in conjunction with the static sandwich-type heat exchange structure, achieves efficient and uniform enhanced cooling of the gas medium. This effectively reduces the gas temperature entering the pump chamber from the source, solving the problem of vacuum level reduction and operational reliability issues caused by the micron-level gap between the stator and rotor of the Roots screw vacuum pump leading to gas temperature rise. Attached Figure Description
[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0018] Figure 1 This is a schematic diagram of the structure of this utility model;
[0019] Figure 2 This is a cross-sectional structural diagram of the present invention;
[0020] Figure 3 This is a schematic diagram of the gas flow structure of this utility model.
[0021] In the diagram: 1. Pump chamber; 2. Cooling source; 21. Hollow shell; 22. Cross-curved flow channel. Detailed Implementation
[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0023] Please refer to Figures 1-3 This embodiment proposes a Roots screw vacuum system with a cooling device, comprising:
[0024] Pump chamber 1;
[0025] A cooling source 2 is disposed at the air inlet end of the pump chamber 1, and its axial direction coincides with the exhaust end of the pump chamber 1. The cooling source 2 includes:
[0026] The cylindrical hollow shell 21 has an internal cooling cavity for the flow of liquid cooling medium.
[0027] Two intersecting curved flow channels 22, located inside the hollow shell 21 and extending axially, divide the cooling cavity into a circumferentially enclosed liquid cooling zone and an internal airflow zone, forming an axial sandwich heat exchange structure.
[0028] Among them, the two intersecting curved flow channels 22 guide the intake airflow to generate two opposing vortices. The interaction of the two opposing vortices, together with the sandwich heat exchange structure, constitutes enhanced cooling of the gas medium.
[0029] To address the issue of gas temperature rise caused by the small gap between the stator and rotor in a vacuum pump, a cooling process is implemented before the gas flow is introduced. The liquid inlet of the hollow shell 21 is connected to an external medium inlet, such as a water pump or other device capable of generating negative pressure. The liquid outlet of the hollow shell 21 is connected to an external receiver. The operating principle after operation can be derived layer by layer as follows:
[0030] Phase 1: When the system starts working, the external liquid cooling medium is introduced into the cooling chamber of the hollow shell 21 and flows continuously. The sandwich-style heat exchange structure, separated by two intersecting curved flow channels 22, begins to function. Specifically, the circumferentially enclosed liquid cooling zone forms a uniform and powerful low-temperature shell, while the internal airflow zone is completely surrounded by this low-temperature shell. This structure establishes an ideal foundation for heat exchange, meaning that no matter how the subsequent airflow flows within the channels, its circumferential position maintains the closest distance to the efficient cooling interface, laying the structural foundation for uniform cooling.
[0031] The second stage: The gas to be processed from the vacuum system enters through the inlet end of the intersecting curved flow channel 22 at the top of the hollow shell 21. Crucially, the gas does not simply flow through a straight channel, but is forcibly divided into two independent gas streams by the two intersecting curved flow channels 22. Guided by the curved walls of the flow channels, the flow paths of these two gas streams are significantly extended, and they gain kinetic energy, forming two opposing vortices. These two vortices collide head-on at an optimal angle at the predetermined intersection point of the flow channels.
[0032] Specifically, this collision and fusion process produces two effects. First, the collision converts the kinetic energy of the airflow into internal energy, generating strong turbulence and micro-vortices, which completely destroys the laminar thermal boundary layer that may form near the wall and hinder heat transfer. Second, the gas with a higher temperature from the center of the cross-curved flow channel 22 is forced to mix with the gas with a lower temperature near the cooling wall, achieving instantaneous temperature equilibrium on the flow channel cross section and avoiding uneven cooling.
[0033] The third stage: The aforementioned dynamic airflow organization (vortex collision) and static heat exchange structure (sandwich layer) do not work independently, but constitute a deeply synergistic organic whole. The dynamic process empowers the static structure. The intense vortex collision and mixing is equivalent to an invisible stirrer, continuously pushing all gas molecules to the flow channel wall, which serves as the heat exchange interface. This greatly enhances the rate and uniformity of cold energy transfer from the wall to the airflow core, solving the heat transfer bottleneck that may exist in the static structure. The static structure provides a guarantee for the dynamic process. The circumferentially enclosed liquid cooling zone ensures that no matter where the vortex mixes the gas, its surroundings are always an efficient and uniform cooling interface, providing a fundamental guarantee for continuous and dead-angle-free heat dissipation.
[0034] The direct technical effect of this synergy is that every moment the gas flows in the channel, it simultaneously experiences the triple effects of path extension, enhanced disturbance, and maximized heat exchange interface. Thus, within an extremely short axial distance, it achieves the cooling effect that traditional designs require longer channels or larger heat exchange areas, thereby realizing enhanced heat exchange.
[0035] After being processed by the aforementioned synergistic cooling mechanism, the gas entering the pump chamber 1 of the Roots screw vacuum pump becomes significantly cooled and uniformly distributed cold gas. This brings about a fundamental improvement at the system level. The micron-level gap between the rotor and stator in the pump chamber 1 will not disappear due to the thermal expansion effect of the high-temperature gas, fundamentally avoiding the risks of friction, wear, or even jamming.
[0036] Furthermore, such as Figures 2-3 As shown, the axial projections of the two intersecting curved flow channels 22 form a continuous X shape on a plane perpendicular to the axis of the pump chamber 1, with an intersection angle of 50°-130°.
[0037] In the acute angle range (approximately 50°-80°), the two airflows do not collide head-on but converge at a smaller angle. This generates a strong shearing effect, causing the airflows to tear at each other and entrain surrounding fluid, forming a series of smaller, more widely distributed vortices. This mode can very efficiently strip and disrupt the thermal boundary layer, while continuously entraining cold gas near the cooling wall to the center of the flow channel, achieving extremely uniform lateral mixing. It provides strong but not overly violent mixing, ensuring efficient heat transfer while helping to control pressure loss.
[0038] In the near-right-angle range (approximately 80°-100°), when the airflows nearly intersect perpendicularly, the collision is most direct and intense. This is similar to two high-speed water jets firing at each other, where kinetic energy is directly converted into intense turbulence and pressure pulsations, generating the strongest disturbance intensity. This has the most significant bombardment effect on the core area of the airflow and can most thoroughly break down temperature stratification, which is particularly crucial for handling gases with extremely high initial temperatures or those requiring instantaneous and powerful cooling.
[0039] In the obtuse angle range (approximately 100°-130°), the main direction of the airflow after the collision will be significantly deflected, forming a more complex, merged composite vortex field. While achieving effective mixing, it is more conducive to guiding the airflow towards the next section of the flow channel, preparing the flow for multiple intersections in the "continuous X-shaped" structure, helping to maintain the continuity of disturbances within the entire flow channel, and optimizing the overall flow resistance.
[0040] Furthermore, such as Figures 2-3 As shown, the diameter of the continuous X-shaped flow channel of the two intersecting curved flow channels 22 increases in a gradient manner along the gas flow direction.
[0041] The gas initially reaches its highest temperature, largest specific volume, and fastest velocity upon entry. By maintaining a small flow cross-section, the gas maintains a high velocity and kinetic energy in the first half of the flow path. To ensure intense collisions at the intersection, if the initial pipe diameter is too large, the velocity will rapidly decrease, resulting in insufficient vortex intensity and significantly diminishing the core collision fusion effect. High velocity translates to a higher Reynolds number and stronger turbulence, which establishes extremely high initial heat transfer efficiency during the stage with the largest temperature difference, achieving rapid cooling. As the gas is continuously cooled during flow, its temperature decreases, and its volume shrinks. The gradually increasing pipe diameter compensates for this volume shrinkage, preventing flow instability or additional flow resistance due to excessively low velocity, thus maintaining a smooth and stable flow field. By reducing the flow resistance in the latter part of the flow path, the overall pressure drop of the cooling device is effectively controlled. This is crucial for maintaining the inlet pressure of the vacuum pump and reducing its operating load, achieving a balance between efficient cooling and low system energy consumption.
[0042] Furthermore, such as Figures 2-3As shown, the two intersecting curved flow channels 22 form a collision and fusion region of two opposing vortices, which coincides axially with the section in the sandwich heat exchange structure where the liquid cooling zone is most fully covered.
[0043] At the instant of the collision between the two opposing vortices, the kinetic energy of the gas is converted into turbulent energy, and microscopic particles undergo intense friction and collision. This region is the hotspot with the highest local heat generation rate and instantaneous temperature in the entire flow channel. Simultaneously, it is also the region with the most complete liquid cooling coating and the strongest cooling capacity. Collision fusion is a strong mechanical mixing process, inherently designed to equalize temperature. When this process occurs in the environment with the strongest cooling capacity, its effect is amplified. Through this spatial overlap design, the two core principles of dynamic vortices and static coating are no longer merely complementary but completely integrated, transforming the system's cooling behavior from reactive to predictive and suppressive.
[0044] Furthermore, such as Figure 3 As shown, the continuous X-shaped flow channels of the two intersecting curved flow channels 22 undergo at least three intersecting fusions in the axial direction.
[0045] The first collision breaks the initial laminar flow state and major temperature stratification, achieving preliminary, coarse-grained mixing; the second collision re-stirs the initially mixed gas flow, eliminating any large temperature inhomogeneities that may remain after the first mixing; the third and subsequent collisions perform final fine homogenization, eliminating all microscale temperature gradients and ensuring that no local area of gas can escape being mixed and cooled multiple times, achieving temperature uniformity close to the theoretical limit.
[0046] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A Roots screw vacuum system with a cooling device, characterized in that, include: Pump chamber; A cooling source is disposed at the air inlet end of the pump chamber, which is axially aligned with the air outlet end of the pump chamber. The cooling source includes: A columnar hollow shell, the interior of which forms a refrigeration chamber for the flow of liquid cooling medium; Two intersecting curved flow channels, located inside the hollow shell and extending axially, divide the cooling cavity into a circumferentially enclosed liquid cooling zone and an internal airflow zone, forming an axial sandwich-type heat exchange structure. The two intersecting curved flow channels guide the intake airflow to generate two opposing vortices. The interaction of the two opposing vortices, together with the sandwich-type heat exchange structure, constitutes enhanced cooling of the gas medium.
2. A Roots screw vacuum system with a cooling device according to claim 1, characterized in that, The axial projections of the two intersecting curved flow channels form a continuous X shape on a plane perpendicular to the pump cavity axis, with an intersection angle of 50°-130°.
3. A Roots screw vacuum system with a cooling device according to claim 2, characterized in that, The diameter of the continuous X-shaped flow channel of the two intersecting curved flow channels increases in a gradient along the gas flow direction.
4. A Roots screw vacuum system with a cooling device according to claim 3, characterized in that, The two intersecting curved flow channels form a collision and fusion region of two opposing vortices, which coincides axially with the section in the sandwich heat exchange structure where the liquid cooling zone is most fully covered.
5. A Roots screw vacuum system with a cooling device according to claim 4, characterized in that, The two intersecting curved flow channels are continuous X-shaped flow channels that are intersected and merged at least three times in the axial direction.