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Calibration Pressure

The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform

Tokihiko Kobata – 1st expert on this subject based on the ideXlab platform

  • reproducibility of Calibration results by 0 a 0 pressurization procedures for hydraulic Pressure transducers
    Measurement Science and Technology, 2014
    Co-Authors: Hiroaki Kajikawa, Tokihiko Kobata

    Abstract:

    This paper focuses on 0-A-0 pressurization for the Calibration of electromechanical Pressure gauges in order to obtain reproducible results by various procedures. In 0-A-0 pressurization, Pressure is released to atmospheric Pressure after finishing each measurement at each Calibration Pressure, and the output reading at atmospheric Pressure is used for offset correction. Pressure gauges are calibrated under various Pressure sequence and time interval conditions in the Pressure range of 10 MPa to 100 MPa using a fully automated Calibration system that uses a Pressure balance as the standard device. Results for a quartz Bourdon-type Pressure transducer are mainly reported. The hysteresis obtained by 0-A-0 pressurization is found to be nearly one-tenth of that obtained by stepwise pressurization. The effect of the previously applied Pressure is less than 10 parts per million even for a random Pressure sequence. Key points for Calibration procedures are proposed from the Calibration results for different time intervals. When the appropriate procedure is used, 0-A-0 pressurization largely reduces the effect of pressurization history, thus yielding highly reproducible Calibration results.

  • Development of low-Pressure Calibration system using a Pressure balance
    Measurement, 2012
    Co-Authors: Momoko Kojima, Tokihiko Kobata

    Abstract:

    Abstract A new Calibration system for low-Pressure is now under development at NMIJ/AIST. The new system is designed to calibrate Pressure transducers in the Pressure range of less than 10 kPa in absolute mode. The Pressure generation technique needs only a single Pressure balance and the Pressure in the bell-jar is used as a Calibration Pressure instead of the system Pressure. In this paper, the outline of the Calibration system and the measurement results are described.

  • Improvement of Pressure generating system for low Pressure Calibration
    SICE Annual Conference 2011, 2011
    Co-Authors: Momoko Kojima, Tokihiko Kobata

    Abstract:

    A Calibration system for low Pressure below 10 kPa has been developed at the National Metrology Institute of Japan (NMIJ/AIST). The standard is realized with a Pressure balance of which the Calibration Pressure is generated in the bell jar. This low-Pressure generating system was first fabricated about a year ago; some improvement has been made to extend the Pressure range and also to archive more efficiency in the operation. Main point of the improvement is the refinement of a weight loading system and a Pressure control system in the bell jar. The details of the instruments are described in this article.

Hashem M. Hashemian – 2nd expert on this subject based on the ideXlab platform

  • Integrated online condition monitoring system for nuclear power plants
    Kerntechnik, 2010
    Co-Authors: Hashem M. Hashemian

    Abstract:

    Online condition monitoring or online monitoring (OLM) uses data acquired while a nuclear power is operating to continuously assess the health of the plant’s sensors, processes, and equipment; to measure the dynamic performance of the plant’s process instrumentation; to verify in-situ the Calibration of the process instrumentation; to detect blockages, voids, and leaks in the Pressure sensing lines; to identify core flow anomalies; to extend the life of neutron detectors and other sensors; and to measure the vibration of reactor internals. Both the steady-state or DC output of plant sensors and their AC signal or noise output can be used to assess sensor health, depending on whether the application is monitoring a rapidly changing (e. g., core barrel motion) or a slowly changing (e. g., sensor Calibration) process. The author has designed, developed, installed, and tested OLM systems (comprised of software/ hardware-based data acquisition and data processing modules) that integrate low-frequency (1 mHz to 1 Hz) techniques such as RTD cross-Calibration, Pressure transmitter Calibration monitoring, and equipment condition monitoring and high-frequency (1 Hz to 1 kHz) techniques such as the noise analysis technique. The author has demonstrated the noise analysis technique’s effectiveness for measuring the dynamic response-time of Pressure transmitters and their sensing lines; for performing predictive maintenance on reactor internals; for detecting core flow anomalies ; and for extending neutron detector life. Integrated online condition monitoring systems can combine AC and DC data acquisition and signal processing techniques, can use data from existing process sensors during all modes of plant operation, including startup, normal operation, and shutdown; can be retrofitted into existing PWRs, BWRs, and other reactor types and will be integrated into next-generation plants.

  • Integrated online condition monitoring system for nuclear power plants
    Kerntechnik, 2010
    Co-Authors: Hashem M. Hashemian

    Abstract:

    Online condition monitoring or online monitoring (OLM) uses data acquired while a nuclear power is operating to continuously assess the health of the plant’s sensors, processes, and equipment; to measure the dynamic performance of the plant’s process instrumentation; to verify in-situ the Calibration of the process instrumentation; to detect blockages, voids, and leaks in the Pressure sensing lines; to identify core flow anomalies; to extend the life of neutron detectors and other sensors; and to measure the vibration of reactor internals. Both the steady-state or DC output of plant sensors and their AC signal or noise output can be used to assess sensor health, depending on whether the application is monitoring a rapidly changing (e. g., core barrel motion) or a slowly changing (e. g., sensor Calibration) process. The author has designed, developed, installed, and tested OLM systems (comprised of software/hardware- based data acquisition and data processing modules) that integrate low-frequency (1 mHz to 1 Hz) techniques such as RTD cross-Calibration, Pressure transmitter Calibration monitoring, and equipment condition monitoring and high-frequency (1 Hz to 1 kHz) techniques such as the noise analysis technique. The author has demonstrated the noise analysis technique’s effectiveness for measuring the dynamic response-time of Pressure transmitters and their sensing lines; for performing predictive maintenance on reactor internals; for detecting core flow anomalies; and for extending neutron detector life. Integrated online condition monitoring systems can combine AC and DC data acquisition and signal processing techniques, can use data from existing process sensors during all modes of plant operation, including startup, normal operation, and shutdown; can be retrofitted into existing PWRs, BWRs, and other reactor types and will be integrated into next-generation plants. © Carl Hanser Verlag, Mu¨nchen.

Shi Jian Yuan – 3rd expert on this subject based on the ideXlab platform

  • Numerical Simulation and Experiments of Hydroforming of Rectangular-section Tubular Component
    Journal of Materials Science & Technology, 2009
    Co-Authors: Shi Jian Yuan, Xianwei Tian, Zhong-jin Wang

    Abstract:

    In order to reduce high Calibration Pressure in hydroforming of components with too small radii, a method wasproposed to manufacture automotive hollow components with rectangular shape by relatively lower Pressure. Theprocess is simulated and analyzed. It is thought that the friction force between the die surface and tube is a mainreason that high Pressure is needed to form small radii. Using the method proposed in this paper, a petal-like sectionshape is first preformed so that the central zones of the four sides of the preform section do not contact with the diesides, thus the tube metal is easy to flow into the transition radii area in Calibration stage. Moreover, a positive forcealong the sides is produced by the internal Pressure, which is beneficial to overcome the friction force and push thematerial into the radii. Therefore, the Pressure for forming the transition radii is greatly reduced and the componentswith small radii can be formed with relatively lower Pressure. For the experimental case conducted in this paper, theforming Pressure is reduced by about 28.6% than the estimated forming Pressure.

  • Thickness distribution of a hydroformed Y-shape tube
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: D.m. Cheng, Bugang Teng, Shi Jian Yuan

    Abstract:

    The process of hydroforming a Y-shape tube was investigated through numerical simulation and experiments. Characteristics of three different forming stages were studied. Thickness distribution of these three stages and the thickness of typical location that varies with internal Pressure during forming process were analyzed when the Calibration Pressure was 136 MPa. It is shown that thickness distribution of the leftward fillet transition region is the thickest, rightward takes the second place, the top of the protrusion is the thinnest after forming. The influence of different Calibration Pressures on the thickness distribution was studied through numerical simulation. It is indicated from the simulation results that with the increase of Calibration Pressure, the biggest thickening rate is not obviously changed; however, the highest thinning rate increased significantly.

  • Reduction of Friction and Calibration Pressure by Section Preform during Hydroforming of Tubular Automotive Structural Components
    Advanced Materials Research, 2008
    Co-Authors: Shi Jian Yuan

    Abstract:

    In the past decade, hydroformed structural components have been widely used in industrial areas in North American and Europe and there is a large potential market in Asia with the development of automotive industry. An extraordinary feature of tube hydroforming is that a hollow component with a three dimension axis and variable closed-sections can be integrally formed, so that the number of component parts is minimized, weight is reduced and stiffness of the part is increased. The section shapes in many automotive hollow components are complex and it is usually difficult or impossible to hydroform these typical sections directly from circular section tube, so that satisfactory preforms are necessary. In this paper, a method to reduce the friction and Calibration Pressure through a petal-like cross-section shape preform is presented and its mechanism is analyzed. Preforms for rectangular, trapezoidal and polygonal sections used in hollow components are investigated and satisfactory preforms are obtained. Taking an engine cradle as example, satisfactory preform section shapes have been designed, by which the thickness distribution was controlled and the flash generated from the die-parting surface in the final forming was avoided. So a carefully selected preform process can contribute significantly to the reduction of friction and Calibration Pressure and it is a dominant factor for successful hydroforming.