Rotameter (flow meter)
OVERVIEW
Rotameters are devices that enable flow to be measured using a float that sits on a stream of gas within a glass tube and rises proportional to gas flow.
USE
- controlled delivery of medical gases at appropriate flow rates
DESCRIPTION
- glass tube containing a float which is elevated by a stream of moving gas
- outlet for attachment of tubing
- inlet from pressure regulator device attached to gas source
- control knob
METHOD OF USE
- the float is raised in the tube as gas flow increases
- cylinder markings allow determination of flow rate
- reading is taken at the centre of the float
- glass cylinder must be upright
- float should spin (shows that it is not stuck)
COMPLICATIONS
- Incorrect function if not held vertically
- float can stick if excess static electricity/debris
- breakage of glass cylinder
- malfunction of valve controlling flow
OTHER INFORMATION
- Different meters are required for different gases as flow rates depend on gas properties such as viscosity and density
- Different flow meters are used for different purposes (e.g. paediatric 0–5 L/min; and adult 0–15 L/min)
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
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