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

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.

[1]  A. Ochkov,et al.  Algorithm for Determining Optimum Runner Number in the Blading Section of a Turbomolecular Pump , 2020 .

[2]  A. H. Isfahani,et al.  A New Relaxation Time Model for Lattice Boltzmann Simulation of Nano Couette Flows in Wide Range of Flow Regimes , 2019, Journal of Applied Fluid Mechanics.

[3]  E. Svichkar,et al.  Calculation method of pumping characteristics of high-vacuum system with turbomolecular vacuum pump , 2018 .

[4]  M. Eskandari,et al.  On the Expedient Solution of the Boltzmann Equation by Modified Time Relaxed Monte Carlo (MTRMC) Method , 2018 .

[5]  Fan-Chun Hsieh,et al.  Pumping performance analysis on turbomolecular pump , 2012 .

[6]  Firat Oguz Edis,et al.  Fast cell determination of the DSMC molecules in multi-stage turbo molecular pump design , 2011 .

[7]  S. Giors,et al.  New spiral molecular drag stage design for high compression ratio, compact turbomolecular-drag pumps , 2010 .

[8]  E. Merzari,et al.  Numerical study of a single blade row in turbomolecular pump , 2009 .

[9]  M. Hablanian.  Engineering aspects of turbomolecular pump design , 2007 .

[10]  S. Hosseinalipour,et al.  A continuum model for pumping performance of turbomolecular pumps in all flow regimes , 2004 .

[11]  A. Goddard,et al.  Empirical and numerical calculations in two dimensions for predicting the performance of a single stage turbomolecular pump , 1998 .

[12]  A. Goddard,et al.  General geometry calculations of one‐stage molecular flow transmission probabilities for turbomolecular pumps , 1995 .

[13]  G. Levi.  Combination of turbomolecular pumping stages and molecular drag stages , 1992 .

[14]  F. Casaro,et al.  Compression ratio and leakage through stages in turbomolecular pumps , 1991 .

[15]  J. Henning.  Thirty years of turbomolecular pumps: A review and recent developments , 1988 .

[16]  S. Pang,et al.  Study of the structure and performance of a new type of molecular pump , 1987 .

[17]  George S. Springer,et al.  A test particle Monte Carlo method , 1973 .

[18]  E. Svichkar,et al.  Method for calculating pumping characteristic of high-vacuum system with turbomolecular vacuum pump , 2018 .

[19]  H. Ninokata,et al.  The pumping performances of the turbomoleculae pump simulated by direct simulation monte carlo method , 2005 .

[20]  Charles H Kruger,et al.  The axial-flow compressor in the free-molecule range , 1960 .