/ RDLs
/ ISO 15926 Part 4: Core reference data - Edition 4
/ MASS FLOW MEASURING ELEMENT - SONIC NOZZLE
MASS FLOW MEASURING ELEMENT - SONIC NOZZLE
Definition
A <MASS FLOW MEASURING ELEMENT - SONIC NOZZLE> is an <INSTRUMENTATION ITEM> and a <MASS FLOW MEASURING ELEMENT> that is operated by pressurizing the inlet of a venturi or evacuating its outlet in order to achieve an Inlet to Outlet pressure ratio of 1.4 to 1 or greater. This ratio maintains the Nozzle in a &amp;amp;amp;quot;choked&amp;amp;amp;quot; or &amp;amp;amp;quot;sonic&amp;amp;amp;quot; state. In this state, only the upstream pressure and temperature influence the flow rate of gas through the Nozzle. The flow rate through the Nozzle becomes nearly a linear function of the inlet pressure which increases the thereby doubling the flow rate of gas