User`s manual
AX2200/AX2300 Instruction Manual Chapter 1 Introduction
CM2-AX2200-2001 (Rev. 4, 4/2014) 1-3
How the AX2000Series Vortex Mass Flow Meter Oper-
ates
Figure 1-1. In-Line Vortex Multi-Parameter Mass Flow Meter
azbil Series AX2200 and AX2300 Multi-Parameter Vortex Mass Flow
Meters use a unique sensor head to monitor mass flow rate by directly
measuring three variables–fluid velocity, temperature and pressure. The
built-in flow computer calculates the mass flow rate and volumetric flow
rate based on these three direct measurements. The velocity, temperature
and pressure sensing head is built into the vortex meter’s flow body. To
measure fluid velocity, the flow meter incorporates a bluff body (shedder
bar) in the flow stream and measures the frequency of vortices created by
the shedder bar. Temperature is measured using a platinum resistance
temperature detector (PRTD). Pressure measurement is achieved using a
solid-state pressure transducer. All three elements are combined into an
integrated sensor head assembly located downstream of the shedder bar
within the flow body.
Velocity Measurement
The AX2000Series vortex velocity sensor is a patented mechanical design
that minimizes the effects of pipeline vibration and pump noise, both of
which are common error sources in flow measurement with vortex flow
meters. The velocity measurement is based on the well-known Von Kar-
man vortex shedding phenomenon. Vortices are shed from a shedder bar,
and the vortex velocity sensor located downstream of the shedder bar
senses the passage of these vortices. This method of velocity measurement
has many advantages including inherent linearity, high turndown, reliabil-
ity and simplicity.