The Experts below are selected from a list of 501 Experts worldwide ranked by ideXlab platform
Shigeka Yoshimoto - One of the best experts on this subject based on the ideXlab platform.
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Development and performance of a magnetic ionic liquid for use in vacuum-compatible non-Contact Seals
Precision Engineering, 2017Co-Authors: Takao Okabe, Daichi Moritaka, Masaaki Miyatake, Yukishige Kondo, Shinya Sasaki, Shigeka YoshimotoAbstract:Abstract For the electron-beam machining of optical media, a very low rotational speed is required to enable the precise fabrication of grooves of various depths and widths. In addition, a lubricant with a very low vapour pressure, such as an ionic liquid, and a vacuum chamber are needed to avoid contamination of workpieces. Accordingly, the development of a vacuum-compatible hydrostatic bearing using an ionic liquid is required to satisfy these rotational conditions and nanometre-order machining accuracy. To use a hydrostatic bearing in a vacuum environment, a non-Contact vacuum Seal is needed to avoid leakage of the ionic liquid used as the lubricant. Furthermore, making a non-Contact Seal using an ionic liquid requires the development of a new type of magnetic ionic liquid. Therefore, this paper describes the development of such a magnetic ionic liquid, which consists of magnetite (Fe3O4) particles, a newly synthesized dispersant, and a pyridinium-based ionic liquid. The outgassed products from this magnetic ionic liquid were measured when it was applied to a non-Contact Seal in a vacuum of about 10−6 Pa. In addition, its mechanical properties, such as viscosity and burst pressure as a non-Contact Seal, were measured. From these investigations, it was found that the developed magnetic ionic liquid would meet the requirements for non-Contact Seals to be used in vacuum-compatible hydrostatic bearings.
Takao Okabe - One of the best experts on this subject based on the ideXlab platform.
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Development and performance of a magnetic ionic liquid for use in vacuum-compatible non-Contact Seals
Precision Engineering, 2017Co-Authors: Takao Okabe, Daichi Moritaka, Masaaki Miyatake, Yukishige Kondo, Shinya Sasaki, Shigeka YoshimotoAbstract:Abstract For the electron-beam machining of optical media, a very low rotational speed is required to enable the precise fabrication of grooves of various depths and widths. In addition, a lubricant with a very low vapour pressure, such as an ionic liquid, and a vacuum chamber are needed to avoid contamination of workpieces. Accordingly, the development of a vacuum-compatible hydrostatic bearing using an ionic liquid is required to satisfy these rotational conditions and nanometre-order machining accuracy. To use a hydrostatic bearing in a vacuum environment, a non-Contact vacuum Seal is needed to avoid leakage of the ionic liquid used as the lubricant. Furthermore, making a non-Contact Seal using an ionic liquid requires the development of a new type of magnetic ionic liquid. Therefore, this paper describes the development of such a magnetic ionic liquid, which consists of magnetite (Fe3O4) particles, a newly synthesized dispersant, and a pyridinium-based ionic liquid. The outgassed products from this magnetic ionic liquid were measured when it was applied to a non-Contact Seal in a vacuum of about 10−6 Pa. In addition, its mechanical properties, such as viscosity and burst pressure as a non-Contact Seal, were measured. From these investigations, it was found that the developed magnetic ionic liquid would meet the requirements for non-Contact Seals to be used in vacuum-compatible hydrostatic bearings.
Wang Rui - One of the best experts on this subject based on the ideXlab platform.
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Theoretical and experimental investigation of variable stiffness finger Seal
'Informa UK Limited', 2020Co-Authors: Zhang Yan-chao, Yin Ming-hu, Zeng Quan-ren, Wang Ting, Wang RuiAbstract:A finger Seal is a flexible and dynamic Contact Seal, and many researches and experiments have proved its application potential in aviation engines, gas turbines, and other equipment. However, the contradiction between hysteresis leakage and wear life in the design and initial installation condition of finger Seals seriously affects the integrated performance design effect. A variable stiffness finger Seal is investigated in the present study to resolve the aforementioned problems, and the influence of initial installation condition is considered. First, a theoretical model of the finger Seal is established to calculate the hysteresis characteristic and Contact pressure between finger feet and rotor. The performances of the variable stiffness finger Seal and traditional involute curved finger Seal are compared to confirm the advantages of the variable stiffness finger Seal. The results show that the initial conditions such as rotor structure and support bearing clearance have an important influence on the accuracy of finger Sealing performance calculation. In addition, the variable stiffness structure improves the hysteresis characteristic of the finger Seal with virtually no loss of wear life under low pressure differential and reduces the hysteresis rate by more than 50%. Under high pressure differential, the variable stiffness structure reduces the average Contact pressure by more than 25%. Therefore, the leakage and wear performance of the finger Seal are simultaneously improved by the variable stiffness structure. This characteristic does not change with an increase in rotor excitation. This indicates that the variable stiffness finger Seal provides good synthetic performance and high dynamic adaptability to random operating conditions
Andreas Tünnermann - One of the best experts on this subject based on the ideXlab platform.
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Contact-free exhaust system for vacuum compatible gas bearing guides
Precision Engineering, 2012Co-Authors: Nils Heidler, Christoph Schenk, Gerd Harnisch, Stefan Risse, Gerhard Schubert, Ramona Eberhardt, Andreas TünnermannAbstract:Abstract Using linear gas bearing guides in a high vacuum environment, the common method to keep the vacuum quality is to exhaust the gas emitted by the bearing pads before leaking into the vacuum chamber. Thereby the exhaust tubes between the guide and the exhaust pumps should interfere with the guide as little as possible while maintaining a flexible connection and a highly effective exhaustion rate. A novel exhaust system that implements these requirements is described within this paper. The major achievement was the realization of two exhaust tubes slidable into one another combined with the known method of non-Contact clearance Seals, thus enabling an highly efficient and yet disturbance free exhaustion. This setup was developed and characterized at static and dynamic conditions. An analytical model for dimensioning the non-Contact Seal was worked out and experimentally verified. The number of Seal stages and the clearance height were identified as the major impact factors on the leakage rate of the setup. It is concluded that the investigated approach is very suitable for vacuum compatible gas bearing guides since a vacuum level in the order of 10 −4 Pa was maintained during the experiments.
Daichi Moritaka - One of the best experts on this subject based on the ideXlab platform.
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Development and performance of a magnetic ionic liquid for use in vacuum-compatible non-Contact Seals
Precision Engineering, 2017Co-Authors: Takao Okabe, Daichi Moritaka, Masaaki Miyatake, Yukishige Kondo, Shinya Sasaki, Shigeka YoshimotoAbstract:Abstract For the electron-beam machining of optical media, a very low rotational speed is required to enable the precise fabrication of grooves of various depths and widths. In addition, a lubricant with a very low vapour pressure, such as an ionic liquid, and a vacuum chamber are needed to avoid contamination of workpieces. Accordingly, the development of a vacuum-compatible hydrostatic bearing using an ionic liquid is required to satisfy these rotational conditions and nanometre-order machining accuracy. To use a hydrostatic bearing in a vacuum environment, a non-Contact vacuum Seal is needed to avoid leakage of the ionic liquid used as the lubricant. Furthermore, making a non-Contact Seal using an ionic liquid requires the development of a new type of magnetic ionic liquid. Therefore, this paper describes the development of such a magnetic ionic liquid, which consists of magnetite (Fe3O4) particles, a newly synthesized dispersant, and a pyridinium-based ionic liquid. The outgassed products from this magnetic ionic liquid were measured when it was applied to a non-Contact Seal in a vacuum of about 10−6 Pa. In addition, its mechanical properties, such as viscosity and burst pressure as a non-Contact Seal, were measured. From these investigations, it was found that the developed magnetic ionic liquid would meet the requirements for non-Contact Seals to be used in vacuum-compatible hydrostatic bearings.