Paper Info
Title
Influence of the length of lead lines on the response of a variable orifice meter: analysis of sensitivity and settling time
Abstract
Gas flow measurements are pivotal in several medical applications. For instance, mechanical ventilators and applications for respiratory monitoring need flowmeters with strict requirements: they must be accurate, with adequate dynamic response, high sensitivity (especially if used for neonatal purposes), and they must be almost insensitive to the composition of the gas Only few types of flowmeters are may be used in these applications. Among differential pressure flowmeters, characterized by good static and dynamic responses, variable area orifice meters (VAOMs) are gaining large acceptance in applications related to respiratory monitoring, estimation of respiratory function, and mechanical ventilation. VAOMs consist of two main parts: a primary element (basically a restriction), and a secondary element (i.e., a differential pressure transducer). The installation of the primary and the secondary elements can strongly influence the input-output relationship of VAOMs and can introduce relevant bias error. The aim of this study was twofold: i) the experimental assessment of the influence of the lead lines length (L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> ) on the calibration curve of a variable orifice meter; ii) the experimental analysis of the influence of L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> on the step response of the flowmeter in terms of settling time. Results show that the value of L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> influences both the static response and the step response: regarding the static response, the sensor sensitivity significantly decreases with L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> (e.g., the sensitivity decreases from 5.3 Pa/L·min <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> to 4.0 Pa/L·min <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , when L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> increases from 4 cm to 182 cm); concerning the step response, the flowmeter increases the settling time from approximately 20 ms up to 60 ms using L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> values of 4 cm and 182 cm, respectively. The findings of this study can be useful to figure out the impact of the L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> value on the sensor response; in addition may provide useful information to correct the sensor response if it is used in condition of installation different from the one used during the calibration.
Year
DOI
Venue
2018
10.1109/MeMeA.2018.8438738
2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA)
Keywords
Field
DocType
orifice meters,flow measurements,installation of differential flowmeters,variable area orifice meters,mechanical ventilation
Step response,Settling time,Flow measurement,Orifice plate,Pressure sensor,Respiratory monitoring,Calibration curve,Acoustics,Calibration,Mathematics
Conference
ISBN
Citations 
PageRank 
978-1-5386-3393-9
0
0.34
References 
Authors
2
6
Name
Order
Citations
PageRank
Federica Montagna100.34
Emiliano Schena210643.86
C Massaroni35426.42
Chiara Caciotti400.34
Daniela Lo Presti5144.42
Sergio Silvestri65815.86