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Page 34 of 939 Results 331 - 340 of 9382

Liang Zhang, Hulin Guo, Guixiang Lu, Yucheng Chen
Performance Improvement of Stack Simulator

In order to improve the performance of the old Stack Simulator, NIM built two new facilities. One is a close loop wind tunnel, which can simulate the real flue gas conditions. The wind tunnel can change the flow rate, temperature, pressure, gas composition and turbulence in the test section. It is used to calibrate the velocity measurement devices such as three-dimensional pitot tubes used in Relative Accuracy Test Audit (RATA). Another facility is a new Stack Simulator, which can simulate the flow field conditions in the real stack. It is used to evaluate the average velocity measurement of RATA devices.

Elsa Batista, Hugo Bissig, John Morgan, Anders Niemann, Annemoon Timmerman, Florestan Ogheard
Metrology for Drug Delivery project – results and impact

This paper presents the major impacts of the work developed in EMPIR Project - MeDD II, Metrology for Drug Delivery in the reference standards used for flow rate determination of drug delivery devices and the results obtained in each work package, with a special focus on the primary standards developed by the partners using different technologies. These new primary standards were validated via an inter-laboratory comparison using two different type of flow meters and a precision syringe pump, in a range from 1500 nL/min down to 5 nL/min. This inter-comparison was performed between nine participating laboratories, each with different methodologies, measurement principles, flow ranges,operating conditions, and measurement uncertainty values.

Jin Song, Chao Chen, Yiping Liu, Haiyang Li
Investigation on Sampling Flow Rate Calibration Method of Air Sampler

In order to obtain the most accurate and effective sampling flow rate calibration method of air sampler, several different equipments were used under two different installation conditions in this paper. According to the experimental results, the calibration results of ultrasonic flowmeter and special orifice flowmeter will be affected by the installation conditions. Consequently, while ultrasonic flowmeter and special orifice flowmeter are used to sampling flow rate calibration, it is necessary to first calibrate the two flowmeters with filter paper, and then use the corrected results to calibrate the sampling flow rate. Based on the results of further experiments, calibration datas of gas roots flowmeter and special orifice flowmeter are consistent with the results obtained from gas flow standard facilities by negative pressure method, at the same time, there is still an error of 3 % ~ 5 % when corrected ultrasonic flowmeter is used. Therefore, gas flow standard facilities by negative pressure method and gas roots flowmeter can be directly used for sampling flow rate calibration of air sampler, if it is not convenient , special orifice flowmeter which calibrated with filter paper is also a good choice, ultrasonic flowmeter is not recommended.

K-H. Cheong, R. Doihara, N. Furuichi, M. Nakagawa, R. Karasawa, Y. Kato, K. Kageyama, T. Akasaka, Y. Onuma, T. Kato
Measurement of the Infusion Flow Rate Produced by a Novel Non-electric-powered Infusion Pump

Intravenous (IV) fluid therapy is a common medical practice that is widespread worldwide, and the method has remained unchanged for more than a century. The IV bag is suspended from an IV stand or pole, and the pressure created by gravity is used to administer the drug. However, this method inevitably reduces the mobility of patients, and may cause accidents such as falls during movement. To solve these problems faced in home care, nursing home, and hospital settings, this study aims to develop a non-hanging, non-electric-powered IV infusion pump with reasonable portability and operability. In this study, instead of gravity, atmospheric pressure is used as the driving force. The infusion device developed is required to achieve a certain level of dosing stability and accuracy, in line with medical guidelines and ideally as comparable to the existing gravity method. We developed a number of prototypes based on different pressurization mechanisms using vacuum piston cylinders as the driving source in order to find an optimum mechanism capable to produce a stable flow rate comparable to the suspended drip system. Tests on performance in terms of discharged flow rate were conducted on three feasible prototypes based on three different pressurization mechanisms, using a gravimetric test bench built for this purpose. The tests show that the pressurization mechanism using an inflating air bag to compress a drip bag has the best performance in terms of flow rate stability.

XING Jing-fang, QU Hong-qiang, HUI Ji, ZHENG Xue-jing, HU Fang-shu, WANG Ying-jie
Simulation and optimization study on the methane combustion chamber

This paper simulated and optimized the combustion chamber of the direct metering of the natural gas calorific value experimental platform. This material conducted a numerical simulation of methane combustion in the combustion chamber using ANSYS Fluent software, and the effects of different mixture inlet pipe length, combustion chamber diameter, and methane nozzle diameter on carbon monoxide emission concentration were studied. Aim to promote the complete combustion of methane, a more appropriate combustion chamber structure, and size were determined through carbon monoxide emission concentration. Through the comparison and analysis of the temperature field, velocity field, and concentration field of each component, it is suggested to set the length of the inlet pipe to 25 mm, and set the diameter of the combustion chamber and methane nozzle as 44 mm and 1.5 mm, respectively. After optimization, carbon monoxide emission concentration decreased from 27.9 PPM to 17.8 PPM, decreasing by 36.2 %.

X. Zheng, X. Zhipeng, J. Qing, Z. Gaoming, T. Jianbing
A Novel Multi-Parameter Calibrator for Ventilator Tester Based on Reciprocating Plunger

Ventilators are widely needed when the COVID-19 is a global outbreak, and they are used to provide mechanical ventilation for patients who are physically unable to breathe, or breathe insufficiently. A ventilator tester is an instrument used to verify and calibrate ventilation parameters of ventilators like gas flow, tidal volume, frequency. As a measuring device, the ventilator tester also needs to be calibrated periodically. And different parameters are usually calibrated with different devices. In order to improve calibration efficiency and accuracy, a novel multi-parameter calibrator for ventilator tester based on reciprocating plunger is proposed in this work. The system composition is introduced and mathematical models are deduced. According to calibrating regulation, different calibrating modes are simulated and realized.

R. Doihara, K.-H. Cheong, N. Furuichi
Evaluation of Microflow Calibration Rig using Static Weighing System with Flying Start-and-Finish Method

A Liquid microflow calibration rig was designed and evaluated. The developed calibration rig has a static weighing system and improved diverter valves for small flow rates. The weighing system succeeded in reducing an uncertainty due to an evaporation effect by using a detachable weighing tank. Experimental results of evaporation effect were introduced. In this study, two types of devices were introduced so that a Flying Start-and-Finish (FSF) method was implemented into the static weighing system. One of these devices is a set of diverting valves, and the other is a syringe pump with a linear encoder. Estimation tests were conducted. Diverter timing errors for the set of diverting valves were estimated to be about 6 ms.

Tao Meng, Chang Zhou, Li Liu, Huichao Shi, Dongjun Li, Bo Wu
Establishment of Micro Liquid Flow facility at NIM

In order to meet the needs of micro-flow measurement in industrial, biological and medical fields, the National Institute of Metrology (NIM) has established a micro liquid flow facility based on dynamic weighing method, with the flow rate range of 100 nL/min ~ 150 mL/min. The facility is composed of two sets of high accuracy electronic balances as the main standard, and three Coriolis mass flowmeters and two sets of independentpipeline systems according to different flow rate ranges. It has been designed a special degassing, a filter and a pipe air exhausting system, as well as a group of weighing containers and syringes of different specifications. An acquisition method of weighing value based on the fluctuation frequency is adopted to effectively reduce the uncertainty introduced by dynamic reading. A ‘dual time’ method is used to realize the synchronization between weighing system and meter under test by the "time stamp" with resolution of 1 ms. The uncertainty sources of balance that came from weighing accuracy of mg magnitude, short-term drift and long-term stability are evaluated by experimental method. In addition, the uncertainty introduced by liquid evaporation and capacity change of middle pipe are also analyzed. The results show that the facility uncertainty is better than 1.5 % (k = 2) at 100 nL/min flow rate, and the uncertainty is better than 0.1 % (k = 2) when the flow rate is above 1 mL/min.

S. H. Lee, Y. Zeng, K.-C. Tsai, K.-H. Cheong, T. Chinarak
Intercomparison of micro-liquid flow standard system in APMP

A pilot study was conducted to compare the microflow rate from 2 to 200 g/h in the APMP TCI project (TCFF_01_TCI2019). A syringe pump (Chemyx Nexus 3000) and Coriolis flowmeter (Bronkhorst M12) were used as the transfer standards. The comparisons were coordinated in the KRISS institute, which was also responsible for the pilot study. The volumetric flow rate was measured using a syringe pump and the measured flow rates were 33, 100, 333, 500, and 1000 μL/min and the institutes that participated in the international comparison of micro-liquid volumetric flow rates were KRISS, NMC A*STAR, and CMS, all of which used water as the working fluid. To measure the mass flow rate, a Coriolis flow meter was used; the flow rates were 2, 6, 20, 60, and 200 g/h and the institutes that participated in this international comparison of micro-liquid mass flow rates were KRISS, NMC A*STAR, CMS, NMIJ, and NIMT. All of the participating institutes used water as the working fluid, except for the NMIJ, which used light oil. The En values for the syringe pumps and mass flow meters were calculated based on reference values and were less than 1 for all the flow rates determined by the participating institutes. Therefore, the international equivalence of the micro-liquid flow standard system of the participating APMP institutions was confirmed.

Chen Fan, Du Bin, Shi Huichao, Meng Tao, Li Wenlong
Design and Optimization of Graphene Membrane Differential Pressure Microflowmeter Based on CFD

In view of the design requirements of the measurement pipeline of the differential pressure micro-flow meter based on graphene membrane, the relationship between the pressure difference and the flow velocity between different pressure points in the micro-pipe was deeply studied, and the relationship between the flow rate and the pressure difference in the pipeline was established. The relational model is verified by CFD simulation calculation. The influence of parameters such as the diameter of the pipe, the length of the pressure pipe and the inlet flow rate on the measurement results were studied respectively, which provided a reference for the optimal design of the sensitive structure of the differential pressure micro flowmeter based on the graphene membrane.

Page 34 of 939 Results 331 - 340 of 9382