Combination of turbomolecular pumping stages and molecular drag stages

Levi, G.

doi:10.1116/1.577947

Cited by 13 publications

(2 citation statements)

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“…The compound turbo pump, which complements the conventional TMP design by incorporating a turbo-drag section on the same rotation shaft, permits discharge pressures of 1000 to 2000 Pa. Meanwhile, Levi (1992) developed another type of pump, called a hybrid pump, which combines different impellers on the same axis without increasing the number of stages. Furthermore, Hablanian (1994) reviewed the development history of turbine-type, high vacuum pumps and noted that the optimization process for designing a generalpurpose turbopump for high-vacuum use is incomplete.…”

Section: Review Of the Turbo Pump Designsmentioning

confidence: 98%

Pumping Speed Measurement and Analysis for the Turbo Booster Pump

Jou¹,

Tzeng²,

Liou³

2004

The International Journal of Rotating Machinery

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This study applies testing apparatus and a computational approach to examine a newly designed spiral-grooved turbo booster pump (TBP), which has both volume type and momentum transfer type vacuum pump functions, and is capable of operating at optimum discharge under pressures from approximately 1000 Pa to a high vacuum. Transitional flow pumping speed is increased by a well-designed connecting element. Pumping performance is predicted and examined via two computational approaches, namely the computational fluid dynamics (CFD) method and the direct simulation Monte Carlo (DSMC) method. In CFD analysis, comparisons of measured and calculated inlet pressure in the slip and continuum flow demonstrate the accuracy of the calculation. Meanwhile, in transition flow, the continuum model of CFD is unsuitable for calculating such rarefied gas. The pumping characteristics for a full 3D model on a rotating frame in transition and molecular regimes thus are simulated using the DSMC method and then confirmed experimentally. However, when the Knudsen number is in the range 0.5 < Kn < 0.1, neither CFD computation nor DSMC simulation is suitable for analyzing the pumping speed of the turbo booster pump. In this situation, the experimental approach is the most appropriate and effective method for analyzing pumping speed. Moreover, the developed pump is tested using assessment systems constructed according to ISO and JVIS-005 standards, respectively. Comparisons are also made with other turbo pumps. The compared results show that the turbo booster pump presented here has good foreline performance.

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Section: Review Of the Turbo Pump Designsmentioning

confidence: 98%

Pumping Speed Measurement and Analysis for the Turbo Booster Pump

Jou¹,

Tzeng²,

Liou³

2004

The International Journal of Rotating Machinery

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“…F. Casaro studied the leakage of turbomolecular pumps in detail, analyzed the effect of leakage on the compression ratio and proposed a specific way to implement improved spacer rings to reduce leakage [2]. G. Levi found that the structure of the turbine stage and the traction stage of the hybrid molecular pump affected pumping performance and proposed two options, changing several stages of blades at the turbine-stage articulation and adding a disc transition structure, to improve the pumping performance [3]. Amoli proposed a conceptual molecular pump with the ability to pump over a wide range; although not successfully applied, this concept provides a guiding direction for the development of molecular pumps [4].…”

Section: Introductionmentioning

confidence: 99%

The Pumping Performance of a Multiport Hybrid Molecular Pump and Its Effect on the Inspection Performance of a Helium Mass Spectrometer Leak Detector

Wang

Hou

et al. 2022

Applied Sciences

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The multiport hybrid molecular pump is a new type of molecular pump that was specifically designed for use in helium mass spectrometer leak detectors. This pump enables the instrument to detect both downstream and counter-current leaks. Access to different extraction ports can fulfill various leak detection requirements, which broadens the application range of these detectors and improves their detection efficiency. This paper establishes a model for the calculation of the parameters of a helium mass spectrometer leak detector under fine inspection conditions, studies the influence of different turbine blade parameters and fine inspection port positions on pumping performance and leak detection, discusses a method to determine turbine blade parameters and fine inspection port positions under fine inspection conditions, and provides a theoretical basis for the development of helium mass spectrometer leak detection technology and the optimization of multiport hybrid molecular pump structures. The results show that reducing the blade inclination and increasing the number and height of blades can improve the detection sensitivity. Provided that the hybrid molecular pump has good pumping capacity, the helium mass spectrometer leak detector can obtain high detection sensitivity when the single blade inclination angle is 25°, the number of turbine blades is 25 to 30, the blade height is 3 mm, and the blade thickness is 0.6 mm to 0.8 mm. To determine the position of the inspection port, it is necessary to consider the actual requirements of the leak detector, such as the working pressure of the inspected parts, the leakage rate and the minimum detectable leakage rate. When the inspection port is between the 7th- and 8th-stage blade rows, optimum working pressure of the mass spectrometer chamber for better leak detection performance and large pressure detection range are guaranteed.

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Turbomolecular pumps designed for plasma processes industry. Turbomolekularpumpen speziell für die Plasmaindustrie

Cerruti¹,

Giors²,

Vissers³

2005

Vak Forsch Prax

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Plasma processes are a very popular method to produce high‐grade quality thin films on many different substrates. There are a large variety of different coating systems. Such systems go from small‐scale machines (i.e. Optical coating systems for ophthalmic lenses and filters), through mid‐size machines (such as systems for deposition on flexible substrates used in the food, electronics and packaging industry or systems used for producing optical and magnetic data storage media), up to large‐area systems (i.e. used for architectural glass coating or in the flat panel display industry). Even if all of these systems look very different, there are few common specific points that characterize most of these applications. The plasma is normally based on Argon, Oxygen, Nitrogen (and more recently Krypton) mixtures in the mid 10–3 mbar range. The base pressure is generally over the mid 10–7 mbar range. The deposition rate is very high and so the demand for gas throughput is high as well. (i.e. a glass coater can ionize more than 2000 sccm of Argon per cathode segment). There is a high probability of debris and particle generation within the process; roughing and venting cycles are fast and sometimes uncontrolled (they can be described as air‐in rushes in some cases). Uptime and reliability are not an option, but a must in industrial production environments. It is therefore difficult to believe that turbo molecular pumps originally designed to reach the 10–10 mbar range with a high number of pumping stages and very tight clearances, are capable to work reliability in this demanding environment. We are keener to think that if we want a reliable and performing pumping solution the design of the turbomolecular pump must be specific and dedicated to the application. Ideally this development process is done side by side with the ultimate equipment users, matching at best process requirements and turbomolecular pump design know‐how. As Varian Vacuum Technologies, we have followed that process and this article is sharing the results.

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Combination of turbomolecular pumping stages and molecular drag stages

Cited by 13 publications

References 0 publications

Pumping Speed Measurement and Analysis for the Turbo Booster Pump

Pumping Speed Measurement and Analysis for the Turbo Booster Pump

The Pumping Performance of a Multiport Hybrid Molecular Pump and Its Effect on the Inspection Performance of a Helium Mass Spectrometer Leak Detector

Turbomolecular pumps designed for plasma processes industry. Turbomolekularpumpen speziell für die Plasmaindustrie

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