Intra Automation digiflow 515, Installation And Operating Manual

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Gas- and Steam Flowcomputer DigiFlow 515 Operating Manual
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1 Introduction
The DigiFlow 515 combines compensation for gas and vapors to the following equations:
1. Ideal Gas: Temperature and pressure correction, compressibility correction not required.
2. General Gas: Temperature and pressure correction with compressibility correction calculated using the
Redlich-Kwong
1
state equation. This equation is suitable for gases with known properties. Information
about common industrial gases are provided in the operating manual.
3. Natural Gas: Compressibility is calculated using the AGA-NX-19-mod equation for natural gases of low
gross caloric value.
4. Steam Flow Computer : Based on the IFC 1967.Mass flow correction of the flowing steam using pressure
and temperature.
5. Energy : The heat quantity is calculated based on enthalpy and mass flow.
6. Energy Balance: . Assuming a mass balance in upstream-and downstream pipe, an energy balance of the
loop is calculated.
Inputs from various of flowmeters are accepted. Examples of these sensors are ( VORTEX ) , turbine, orifice
plate, averaging pitot tubes like ( ITABAR -Flow sensor), wedges and target flowmeters.
To increase the measured flowrange of an ITABAR -Flow sensor, it is possible to use two differential pressure
transmitters whose ranges overlap with automatic crossover in the computer.
The device include a scaleable Pulse Output an two scaleable Alarm Relay Outputs.
Optionally this computer includes:
•
Up to 3 Analog Outputs 0/4 – 20mA.
•
RS485 – Interface.
•
Control Relays for an Sensor–Purge–Unit.
A unique feature available with the serial interface is the ability to print flowrates and totals at programmable time
intervals. This enables the instrument to function as a data logger when used in conjunction with a printer, or
other storage device.
1
Redlich & Kwong,, „An equation of State“, Chem Rev., vol. 44, p233, 1949