(b) High or Low Sensitivity .... Extractive systems can be designed for high sensitivity, by choosing an optical pathlength sufficient to meet the sensitivity requirements, by including a small volume multi-pass sample cell;

(c) Elevated pressure streams....High pressure gas streams can be sampled by reducing the pressure to ambient; etc

(d) Economical.... One analyzer can be multiplexed to monitor several different streams sequentially; or even several different points in the same stream;

(e) Accessible.... The analytical hardware can be located at ground level for easy access, in a temperature-controlled environment, if desired.

(b) Increased system maintenance...... Must maintain the sampling system also;

(c) Generally more expensive than in-situ systems;

(d) Slower response, due to sample transit time.

(e) Measures at a single point; may not be representative of the average composition of a stratified gas stream.

Model 710X
Ambient temperature multigas[X = 1 to 6] NDIR analyzer.

Model 711X
Ambient temperature single(or dual) gas NDIR analyzer.

Model 720X
Heated multigas [X = 1 to 6] NDIR analyzer, maintaining condensible vapors above their dew point.

Model 721X
Heated single (or dual) gas [X = 1 to 6] NDIR analyzer, maintaining condensible vapors above their dew point.

Model 761X
Ambient temp multigas DIR analyzer.

Model 762X
Heated multigas DIR analyzer.

Model 770X
Ambient temp analyzer from California Analytical.

Model 771X
Ambient temp Mini-CEMS from California Analytical.

Model 781X
Ambient temp multigas FTIR analyzer.

Why do we need to use UV absorption also? Complimentary to IR absorption.
(a) Only Spectral Region - Some gases absorb only in the UV, not in the IR. Examples are homonuclear diatomics such as Cl2, F2, (which we measure) as well as H2 and O2 (which we do not measure in the UV ... because O2 is such a strong UV absorber, the O2 in the air makes it impossible to measure H2 or O2 unless the system operates in a vacuum with all the air and hence O2 removed);

(b) Higher Sensitivity - Some gases, such as SO2, NH3 & NO have much stronger absorption bands in the UV than in the IR, so we can measure with higher sensitivity (i.e. lower concentrations);

(b) Single or Dual Beam NDUV Absorption Spectroscopy, dual wavelength ratioing [two narrow bandpass filters are selected, one for a wavelength where the sample gas uniquely absorbs light, and a 2nd for an adjacent reference wavelength, where the sample gases do not absorb light; or

Extractive single gas, NDUV.... Model 511Y (ambient temp) and 521Y (heated), Y=1 or 2

In-Situ multigas,DUV.... Model 560X with an E-6000 optical projection system, or
Model 565X with an on-stream optical projection system & optical fiber connection to a remote analyzer.

Open-Path Ambient Air DUV.... Model 580X

NO = 5 ppm.m,
SO2 = 2 ppm.m,
NH3 = 5 ppm.m;
with a 2% of MMR

detection limit for 1 min response time, and 0.7% of MMR for 10 min response time.

Model 7501..... ambient temperature sampling system, where the sample temperature is reduced to ambient, and the measurement is at ambient temp. [Since most samples contain levels of water that would condense at ambient temperatures, the water must be removed. This technique is often called ¡§cold, dry¡¨].

Model 7502..... heated sampling system, where the sample is kept hot, by heating all system components that it comes in contact with, including the analyzer sample cell. In this way the water does not condense. [This technique is often called ¡§hot, wet¡¨].

Model 7503.... dilution-based sampling system, where the sample is continuously diluted with a precise known volume of clean dry air to lower the sample temperature close to ambient, and to dilute the sample below the dew point so that water and other condensibles do not condense.

Multiplexed..... Model # - Y, where Y= the number of sample points being sequentially monitored. [One analyzer can be time shared between several sampling points, to reduce system cost; (but at the same time this reduces the system response time, and may result in the analyzer not measuring the specific stream at the moment of a process upset)].