HORIBA - Model APNA-370 - Ambient NOx Monitor
The APNA-370 continuously monitors atmospheric NOX, NO2, and NO concentrations using a cross-flow modulated semi decompression chemiluminescence method. The APNA-370 employs an independent, internal dry-method sampling device to achieve the highest levels of sensitivity and accuracy. The dry method, due to its minimal maintenance requirements and capability of continuous monitoring and instantaneous analysis of gas in its unaltered state, has been a preferred method for monitoring the atmospheric pollution.
The APNA-370 uses a combination of the dual cross flow modulation type chemiluminescence principle and the referential calculation method.
This gives it the advantages of the single-detector method plus the ability to do continuous measurements of NOX, NO, and NO2. The design gives great stability and extremely high sensitivity (0.1 ppm F.S.)
Standard equipment includes a drier unit with an automatic recycle function to provide dry ambient air as the ozone source. This makes long-term continuous measurements possible.
The detector uses a silicon photodiode sensor to reduce size and prolong working life.
All the necessary features are built right into a single rack-sized unit, including a reference-gas generator, an ozone-source drier unit, an ozone decomposer, and a sampling pump. No supplemental gas is required.
The chemiluminescence method uses the reaction of NO with O3
A portion of the NO2 generated as the result of this reaction becomes NO2*. As these excited molecules return to the ground state, chemiluminescence is generated in the range of 600 nm to 3,000 nm. The light intensity is in proportion to the concentration of NO molecules and by measuring it we obtain the NO concentration of the sample. A deoxidation converter changes the NO2 to NO, which is measured. In other words, the NO2 concentration can be obtained by the difference between (1) the NOx concentration measured when the sample gas is directed through a converter and (2) the NO concentration measured when the gas is not run through the converter.
- Principle: Cross flow modulation type, reduced pressure chemiluminescence (CLD)
- Application: NO2, NO and NOx in ambient air
- Range: Standard ranges: 0-0.1/0.2/0.5/1.0 ppm; auto range ~ manual range selectable; can be operated by remote switching.
Optional (measurable) ranges: 4 ranges selectable from 0-10 ppm, within 10 times range ratio; auto range ~ manual range selectable; can be operated by remote switching.
- Lower detectable limit: 0.5 ppb(3 sigma)
- Repeatability: ±1.0% of F.S. Linearity: ±1.0% of F.S.
- Zero drift: <LDL/day, at lowest range
±1.0 ppb/week at lowest range
- Span drift: < LDL/day at lowest range
±1.5% of F.S./week
- Response time (T90): Within 90 sec at lowest range
- Sample gas flow rate: Approx. 0.8L/min
- Indication: Measured value, range, alarm, maintenance screen
- Alarms: During AIC, zero calibration error, span calibration error, temperature error in converter, etc.
- On-screen messages are available in four languages: English, German, French, and Japanese.
Input/output: 0-1 V/0-10 V/4-20 mA, to be specified (2 systems: either (1) momentary value and integrated or (2) moving average value)
Ambient temperature: 5-40 C
- Power: 100/110/115/120/220/230/240 VAC, 50/60 Hz (to be specified)
- Dimensions: 430(W)X550(D)X221(H) mm
- Mass: Approx. 21 kg,