VorTek Pro-T, Instruction Manual

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Series M22/M23/M24 Instruction Manual Chapter 1 Introduction
M-000-00010 1-7
its vapor phase. The resulting two-phase flow degrades the liquid calibra-
tion accuracy. For some applications, a valve downstream of the flow me-
ter may be required to increase the pressure in the meter, thereby avoiding
cavitation. The following equation defines the minimum back pressure to
prevent cavitation.
P = 2.9

P + 1.3 P
V
Where:
P = Minimum line pressure five pipe diameters downstream of the flow
meter required to avoid cavitation (psia or bara).

P = Permanent pressure loss across the flow meter (psia or bara).
P
V
= Liquid vapor pressure at actual flowing conditions (psia or bara).
Temperature Measurement
Pro-V Flow Meters use a 1000 ohm platinum resistance temperature detec-
tor (PRTD) to measure fluid temperature.
Pressure Measurement
Pro-V Flow Meters incorporate a solid-state pressure transducer isolated
by a 316 stainless steel diaphragm. The transducer itself is micro-
machined silicon, fabricated using integrated circuit processing technol-
ogy. A nine-point pressure/temperature calibration is performed on every
sensor. Digital compensation allows these transducers to operate within a
0.3% of full scale accuracy band within the entire ambient temperature
range of -40°F to 140°F (-40 to 60°C). Thermal isolation of the pressure
transducer ensures the same accuracy across the allowable process fluid
temperature range of -330°F to 750°F (-200 to 400°C).