GDC-703
Overview
Compensation for the effect of gas composition and concentration on mass flow-controller operation ensures accurate results. Blended gases are within ± 1% of gas concentration accuracy.
Designed to support the wide concentration ranges of MEXA-7000 analyzers, GDC-703 is available in rack-mount and portable-cart configurations.
The GDC-703 uses highly accurate mass-flow controllers to blend a calibration gas with diluent. The cut points range from 100% to 0.2% (1/500th) of the gas value. Controlled by the MEXA-7000 main control unit, GDC-703 supports fully automated analyzer calibration (linearization) and NOx converter-efficiency checks. Mixing divisions are from 0 to 95% at 0.2% increments and 100%.
Features
- Highly accurate and convenient method for linearizing analyzers with wide dynamic measurement range.
- Maximizes test-cell efficiency. Can automatically linearize analyzers during scheduled test-cell down times (e.g., overnight).
- 40 cut-points - with a minimum step-size of 1/500 of the calibration gas value - can be selected as desired, compared to capillary dividers which provide fixed, equally-spaced cut points
- Integrated ozonator supports automatic NOx converter efficiency check.
- Controlled by MEXA-7000 main control unit.
Principle
Uses four Mass Flow Controllers (MFCs) to blend a diluent and component gas. One MFC - with maximum flow rate of 4 L/min - controls the flow rate of diluent gas (nitrogen or air). Three MFCs - with maximum flow rates of 4 L/min, 500 ml/min, and 60 ml/min - control component gas flow rate.
Blending ratio is determined by the flow rates of diluent and component gas at 4 L/min. For example, to achieve 0.2% (1/500th) of calibration-gas value at 4 L/min:
- Span flow is set to 8 ml/min - using the 60 ml/min MFC.
- Diluent flow is set to 3992 ml/min.
- 8 + 3992 = 4000 ml/min.
- 8/4000 = 0.2% of span-gas value.
To achieve 80% of span-gas value at 4 L/min.
- Span flow is set to 3200 ml/min - using the 4 L/min MFC.
- Diluent flow is set to 800 ml/min.
- 3200 + 800 = 4000 ml/min.
- 3200/4000 = 80% of span-gas value.
All MFCs are operated within 10 to 100% of their maximum rated flow.
Manufactured by HORIBA
Specifications
Principle | Mass Flow Controller |
|---|---|
Mixing Divisions | 0~95% at 0.2% divisions and 100% at 4 L/min. |
Repeatability | ± 0.5% |
Accuracy | ± 1.0% |
Flow Rate | 4 L/min. |
Pressure (Supply Gas) | 100 ± 10 kPa |
Pressure (Mixed Gas) | 30 ± 5 kPa |
Base Gas | N2 or Air (selectable in software) |
Materials in Contact with Gases | Stainless (SUS ø30) |
Ambient Conditions | 5-35°C (precision guarantee 15-35°C) |
Power | 0.1 kVA |
Interface | Serial RS-232 to MEXA-7000 MCU |
GDC-703 Converter Checker | |
NOx Conc. Range | 0~10 to 1000 ppm |
Divisions | 1/2500 |
Flow Rate | 2.2 ± 0.4 L/min. |
Pressure (Supply Gas) | NO 100 ± 10 kPa |
Pressure (Mixed Gas) | 30 ± 5 kPa |
Noise | ± 1% of span-gas conc. |
Stability | ± 1% of span/10 min. |
Related SAE Papers
For an independent evaluation of GDC-703, click on the paper's identification number to order from SAE:
"Evaluation of Mass Flow Controller Gas Divider for Linearizing Emission Analytical Equipment."
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