Introduction - Contrec 415 User Manual

1. INTRODUCTION

The Model 415 Gas Flow Computer incorporates compensation for gas
and vapours to the following equations:
1. Ideal Gas Law using temperature & pressure correction, but where
2. General Gases where compressibility is calculated using the
3. Natural Gas using NX-19 2 equation for supercompressibility.
4. Steam Equations for both saturated and superheated steam. Mass
Inputs from a wide range of flowmeters are handled including vortex,
turbine, orifice plate, averaging pitot tubes, wedges, V-Cones and target
flowmeters. In addition, where two differential pressure transmitters are
used across an orifice (or similar device) to increase the measured
flowrange, both D.P. Transmitter inputs can be accepted into the Flow
Computer and scaled separately with automatic crossover.
Options include a 4-20mA re-transmission, high and low flow alarms and
an RS232/422/485 output. A unique feature available with the
RS232/422/485 output 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.
Two versions of the instrument are available, the Model 415R with direct
RTD input, and the 415A with a 4-20mA temperature input. Both accept a
4-20mA pressure input.
The Model 415 is designed to supersede the Models 405GS and 405ST.
1 Redlich & Kwong. "An equation of State". Chem Rev, vol 44, p233, 1949.
2 Par Research Project NX-19. "Extension of Range of Supercompressibility
Tables", American Gas Association, 1962.
415-M-V3.2
compressibility is ignored.
Redlich-Kwong 1 equation.
and energy flowrates are calculated using standard equations to
determine the specific weight and enthalpy of steam.
Introduction 7