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Mori M.,Hitachi - GE Nuclear Energy | Nebu A.,Materials Strength and Reliability Unit | Kanno T.,Hitachi Engineering and Services Co.
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2010

An appropriate flange tightening methods for small bore and low rating piping flange joints are clarified to improve the sealing performance of the bolted flange joints and the workability of flange tightening work. It is said that lubricant on the screw of the bolts and the nutseating surface can minimize the variability of axial force acting on flange bolts, while this process might make it harder to tight the bolts uniformly especially for small bore low rating flanges. So, in this paper the appropriate condition to apply lubricant is clarified by a series of bolt tightening tests and sealing tests results. On the other hand, for the bolted flanges applying spiral wound gaskets, measuring the gasket compress dimensions help us to prevent uneven tightening balance and to perform the appropriate tightening work. Appropriate gasket compress dimensions are also clarified to ensure the sealing performance for the flanges based on the sealing tests results. Based on these test results, recommended flange-tightening methods have been summarized as an instruction and tightening work procedure to improve the sealing performance of the bolted flanges and the workability of flange tightening work. Copyright © 2010 by ASME. Source


Tsumaki Y.,Yanlagata University | Owada H.,Yanlagata University | Kimura K.,Hitachi Engineering and Services Co.
World Automation Congress Proceedings | Year: 2014

Remote camera control plays a crucial role in acquiring detailed information. In our previous work, intuitive camera control with spherical coordinates was proposed for a known environment, which required distance between a camera and gaze point. In this paper, to handle an unknown environment, a small distance sensor is employed alongside an attached 6-DOF camera-arm with low load capability. Unfortunately the sensor sometimes detects the wrong distance, because it is an infrared-distance sensor. In response, an operator support system which displays the measuring error is proposed as well as an adjustable function to correct the error. The system, named 'A Distance-Error Detection and Correction System' is based on a shared-control concept. Past images captured from a different perspective are employed to leverage the superior human capacity to recognize images. Its effectiveness has also been verified by experiments with a real telerobotic system. © 2014 TSI Press. Source


Suzuki K.,Hitachi Engineering and Services Co. | Hoshino N.,Hitachi Engineering and Services Co. | Inomata N.,Tohoku Electric Power Co. | Kimura H.,Tohoku Electric Power Co. | Fujiwara T.,Iwate University
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi) | Year: 2011

This paper describes the influence of wind turbulence on the yaw-control gears of the nacelle in a wind power station. The site is located on Tappi Cape in Aomori prefecture, where major wind turbulence occurs due to the strong western wind and the steep slope of the cape. This paper discusses two adjacent wind towers out of a total of eleven and clarifies the influence of wind turbulence on the leeward wind power generator. Measurements showed that the turbulence and the standard deviation frequently exceeded IEC Wind Turbine Standards. Consequently, the torque applied to the yaw-control gears oscillated with a short time period and its magnitude was frequently greater than 4.8 ton-m (47 kN-m), regarded as the metal fatigue limit. By a method in which the output of the wind turbine generator is controlled, the magnitude of the oscillating torque can be reduced below the limit of material fatigue. © 2011 Wiley Periodicals, Inc. Source


Nakano S.,Hitachi Ltd. | Tsubouchi K.,Hitachi Ltd. | Shiraiwa H.,Hitachi Engineering and Services Co. | Hayashi K.,Hitachi Engineering and Services Co. | Yamada H.,Hitachi Engineering and Services Co.
Proceedings of the ASME Turbo Expo | Year: 2012

Simulation method for load rejection with a 150 kW class radial inflow steam turbine system was proposed to determine over rotational speed at load rejection. Simulations were carried out for several parameters of valves which are operated in an emergency. And load rejection tests were carried out to confirm the machine reliability and to obtain results for comparison with the simulation results. Simulation results show that operation delay times of the steam release and vacuum break valves greatly affect over rotational speed at load rejection. Load rejection tests were done for generator outputs from 69 kW to 113 kW. Maximum over rotational speed of 54,160 rpm was measured at the generator output of 113 kW. Over rotational speed calculated by the dynamic simulation has relatively good agreement with the result for the operation delay time of 0.21 s. If the operation delay time of the steam release valves are kept as 0.21 s at the load rejection for the rated load of 150 kW, the over rotational speed is suppressed within 55,200 rpm which is less than the allowed rotational speed of 56,100 rpm. Copyright © 2012 by ASME. Source


Nakano S.,Hitachi Ltd. | Tsubouchi K.,Hitachi Ltd. | Shiraiwa H.,Hitachi Engineering and Services Co. | Hayashi K.,Hitachi Engineering and Services Co. | Yamada H.,Hitachi Engineering and Services Co.
Proceedings of the ASME Turbo Expo | Year: 2010

A design study for a 150 kW class radial inflow steam turbine system for the bottoming cycle in 2.4 MW class gas engine systems has been completed. The total electrical efficiency of the gas engine can be increased from 41.6 % to 44.2%. A two-stage condensing turbine system is applied to increase output power under the supplied steam conditions from the exhaust heat of the gas engines. The pressure ratio of a high-pressure turbine is 3.5, and that of a low-pressure turbine is 4.6. The blade profiles of both turbines are also designed to make sure the thrust does not exceed 300 N at the rated rotational speed of 51,000 rpm. To simplify the rotor system and to reduce mechanical losses, a permanent magnet generator rotor is applied that is composed of turbine rotors in a common shaft supported by two water-lubricated bearings. The oil supply system is completely eliminated in the turbine system. Design specifications of the turbines are shown, as are operating pressure ratio ranges of upper and lower limits from the start to the rated rotational speed for a stable starting operation. © 2010 by ASME. Source

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