Flammable gases
The analyzer is suitable for measuring flammable gases in general purpose environment (see page 22).
Oxygen analyzer Magnos28 Measurement principle Paramagnetic behavior of oxygen Magnetomechanical oxygen analyzer Sample component and measurement ranges Sample component Oxygen (O2) Smallest measurement range 0–2 vol.% O2 Measurement range quantity 2 measurement ranges Measurement range limits Measurement ranges are freely adjustable; they are factory-set per order to 0–5 vol.% O2 or 0–25 vol.% O2 or 0–100 vol.% O2 or 98–100 vol.% O2. Largest measurement range 0–100 vol.% O2 Measurement ranges should not be set within ignition limits. Measurement ranges with suppressed zero-point Suppressed measurement ranges are freely adjustable in the range 0–100 vol.% O2. Smallest span 2 vol.% O2. The combination of a suppressed and an initial measurement range is not possible. Pressure correction with a pressure sensor is required. A pressure sensor is installed when the analyzer has been ordered with suppressed measurement range. Stability The following data apply only if all influence factors (e.g. flow rate, temperature, atmospheric pressure) are constant. Linearity deviation ≤ 0.5 % of span, at least 0.005 Vol.-% O2 Repeatability ≤ 50 ppm O2 Zero drift ≤ 3 % of span of the smallest measurement range (per order) per week, minimum 300 ppm O2 per week Sensitivity drift ≤ 0.1 vol.% O2 per week or ≤ 1 % of measured value per week (not cumulative), whichever is smaller; ≤ 0.15 % of measured value per three months, minimum 0.03 vol.% O2 per three months Output fluctuation (2 σ) ≤ 25 ppm O2 at electronic T90 time (static/dynamic) = 3/0 sec Detection limit (4 σ) ≤ 50 ppm O2 at electronic T90 time (static/dynamic) = 3/0 sec Influence effects Flow effect ≤ 0.1 vol.% O2 in the 30–90 l/h range Associated gas effect Data regarding the effect of associated gases can be found in IEC 61207-3:2002 “Gas analyzers – Expression of performance – Part 3: Paramagnetic oxygen analyzers”. Temperature effect Ambient temperature in the permissible range – At zero-point: ≤ 0.02 vol.% O2 per 10 °C – On sensitivity: ≤ 0.3 % vol.% O2 per 10 °C Thermostat temperature = 60 °C Air pressure effect – On sensitivity with no pressure correction: ≤ 1 % of measured value per 1 % air pressure change – On sensitivity with pressure correction using integrated pressure sensor (optional): ≤ 0.1 % of measured value per 1 % air pressure change; for highly suppressed measurement ranges ≤ 0.01 % of measured value per 1 % air pressure change or ≤ 0.002 vol.% O2 per 1 % air pressure change, whichever is greater. Power supply effect DC 24 V ± 5 %: within detection limit Position effect Zero-point shift ≤ 0.05 vol.% O2 per 1° deviation from horizontal orientation. Position has no effect on the hard-mounted unit.
Dynamic response Warm-up time < 1 hour 90% response time T90 ≤ 3 sec at a sample gas flow of 90 l/h and electronic T90 time (static/dynamic) = 3/0 sec, gas change from nitrogen to air (see “Gas connections”, applies to an analyzer unit only with Magnos28) Calibration Zero-point calibration With oxygen-free process gas or substitute gas End-point calibration With process gas with a known oxygen concentration or a substitute gas such as dried air Single-point calibration Zero-point calibration with any oxygen concentration, e.g. with nitrogen or ambient air, processed through a cooler or H2O absorber. Pressure correction by means of pressure sensor is recommended for single-point calibration with air. Depending on the measurement task involved, the zero- and endpoints should be verified periodically (recommendation: once a year). Calibration of measurement ranges with suppressed zero-point Highly suppressed measurement ranges (≥95–100 vol.% O2) should only be calibrated with test gases with concentrations in the selected measurement range. Single-point calibration can also be done within a suppressed measurement range. The O2 concentration of the test gas must lie within the measurement range. Materials in contact with the sample medium Analyzer Stainless steel 1.4305 (SAE 303), nickel alloy, glass, PtNi, silicon, gold, PTFE; FPM seals, optional: FFKM75 Gas connectors of the solenoid valve (option in model EL3020) PVDF Gas connections See page 31 Sample gas inlet conditions The analyzer must not be used for measurement of ignitable gas/air or gas/oxygen mixtures. Temperature The sample gas dew point should be at least 5 °C below the temperature throughout the sample gas path. Otherwise a sample gas cooler or condensate trap is required. Water vapor content variations cause volume errors. Pressure The analyzer is operated under atmospheric pressure; the sample gas outlet is open to atmosphere. Internal pressure drop < 5 hPa with standard flow rate 60 l/h. Permissible absolute pressure range: 800–1250 hPa. Operation under lower absolute pressure (e.g. at altitudes above 2000 m) on request. Operation under elevated pressure: A pressure sensor is required for pressure influence compensation. Absolute pressure ≤ 1250 hPa: An optional internal pressure sensor can be connected to the sample gas path. Absolute pressure ≥ 1250 hPa: An external pressure sensor must be connected to the sample gas path. Correction is done externally. Flow rate 30–90 l/h Changes of the sample gas flow rate should be avoided in highly suppressed measurement ranges. Corrosive gases Consultation with ABB Analytical is required if the sample gas contains Cl2, HCl, HF or other corrosive components. FFKM75 seals must be used if the sample gas contains NH3. In this case the integral gas feed cannot be connected to the analyzer. The pressure sensor must not be connected to the sample gas path. Flammable gases The analyzer is suitable for measuring flammable gases in general purpose environment (see page 22).