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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.

Xiaobin Huang, Liang Zhang, Chun Lu
Development of a portable small gas flow transfer standard based on laminar flow technology

Small gas flow measurement is widely applied in aerospace, environmental monitoring, automotive, medical and other fields. To calibrate the small gas flow, a portable transfer standard device based on laminar flow technology is developed, which includes a gas conditioner, laminar flow elements, a pressure sensor, a temperature sensor and a flow computer. The measurement range of the device is (1 ~ 10000) mL/min with a relative expanded uncertainty of U ≤ 0.3 %, k = 2. The device has the capacity to compensate the medium temperature influencing on the flow rate. It can be utilized to calibrate the gas flow whose pressure does not exceed 0.6 MPa. With a compact dimension and weighing 27 kg, the device is easy to be carried. The consistency of the measurement results of the device under different temperature and pressure conditions is studied, and it is verified that the device can be utilized as a transfer standard for both in-laboratory calibration and on-site calibration for small gas flow.

Elsa Batista, Vania Silverio, Florestan Ogheard, Christina Pecnik, Holger Becker, Anders Niemann
MFMET project - Establishing metrology standards in microfluidic devices

This paper presents the objectives and initial outcomes of EMPIR Project 20NRM02 MFMET - Establishing metrology standards in microfluidic devices, funded under the EURAMET EMPIR program of the European Commission, that intends to tackle the lack of metrological specifications for microfluidics. It started in June 2021 with the involvement of 15 partners and will have a duration of three years. The main goal of this project is to contribute to the development of globally accepted standards for microfluidics, with a focus in metrology for the methodologies and fabrication processes that are essential to ensure measurement accuracy and traceability of microfluidic devices and their dissemination to end users in industry (health, pharmaceutical) and academia. This project is expected to create impact, as new calibration guidelines for microfluidics and microfluidic devices will be developed, that are of direct relevance particularly to the industrial partners in the project but also to other user communities. An experimental setup and results from the characterization of the flow rate in a microfluidic device are also given in this work.

H. Bissig, M. de Huu
Dynamic vs constant liquid flow calibrations down to 20 nL/min

Calibration of flow devices is important in several areas of pharmaceutical, flow chemistry, HPLC and microfluidic applications, where dosage of process liquids or accurate measurement of the flow rate are important. The process-oriented liquid itself might influence the performance of the flow device. Therefore, the calibration of the flow meter or microfluidic device with the process-oriented liquid is important and performing dynamic flow profile changes to simulate any dosing process gives important insight in the behaviour of these flow devices and their accuracies under non-constant flow conditions. Therefore, METAS has developed facilities with METAS piston provers to address the issue of measuring with process-oriented liquids non-constant flow profiles for flow rates down to 20 nL/min. The stated measurement uncertainties for the constant flow rate and for the dynamic flow profile changes are 1 % and 2 % at 20 nL/min. The piston provers, the new developed capillary beaker for the gravimetric reference method, validation measurements as well as response time characterization with incompressible and compressible liquids are discussed in this paper.

Hai-Bo Zhao, Han Wu
Development on in -situ flow measurement technology of high performance liquid chromatography

The infusion system (referred to pump) was the heart of High performance liquid chromatography (HPLC), which provided the power of HPLC. The critical parameter of the pump were the accuracy and stability of flow, which were directly related to the consistency and effectiveness of HPLC results. At present, the technical standards of HPLC are mainly JJG705-2014 and EDQM-OMCL, which were that Verification Regulation of Liquid Chromatograph and Quality Control Laboratory of European Medical Administration for flow of HPLC respective. In this study, a new portable HPLC flowmeter (PM-210plus) for HPLC was used. It adopted the volumetric principle, including the fully closed volumetric parts and the special constant force in situ detection structure, which realized in-situ measurement of HPLC flow and data traceability. The flowmeter was calibrated by Dynamic mass method water flow standard device of National Institute of metrology, China (NIM ).Parameters of flow in-situ measurement were designed, including value error, stability, and temperature influence test. After the optimization of conditions, the flow range could be covered from 0.01 mL/min to 5.0 mL/min in situ conditions, the maximum allowable error was within ± 1 %, the stability was within 0.5 %, and each measurement was completed in 3 min. It fully met the requirements of JJG705 field flow measurement, and greatly improved the field measurement efficiency.

L. Liu, C. Zhou, T. Meng
Research on Methods to Reduce the Influence of Medium Evaporation on Liquid Micro-Flow Facility

Liquid micro-flow facility in our country can achieve ultralow flow measurement as low as 100nL/min. In the detection process of liquid micro-flow facility, evaporation is significant for liquid at low flow rate, and if not controlled, the evaporation of the medium will be the main source of uncertainty for liquid micro-flow facility, so it is necessary to correct the evaporation effect during the test. Evaporation occurs mainly during the collection of liquid in the weighing container inside the balance, the effect of evaporation on flow is analysed, and obtains an evaluation method of the effect of reducing evaporation. The influence of balance drift on evaporation was excluded through experiment, and the research on evaporation under uninhibited conditions, evaporation under evaporation trap and oil film coverage were carried out. In addition, the evaporation studies under oil film coverage plus evaporation trap was also implemented. Finally, it is concluded that both the evaporation trap and the oil film covering can effectively inhibit the evaporation of medium, the optimal anti-evaporation method of the liquid micro-flow facility is to cover the paraffin oil film above 0.15 g/cm², which can reduce the evaporation to 0.3 μg/min, and the uncertainty to 0.12 % (k = 2) at the ultralow flow rate of the facility.

Page 3 of 907 Results 21 - 30 of 9067