Analyzers and systems for flue and combustible gas

Multigas infrared analyser Mod. Enox (NDIR)

INTRODUCTION

The Enox multicomponent gas analyzer is an industrial photometer based on the non dispersive photometry in the infrared, for the contemporary measure of several gases.

The technology which has been used is based on correlation filters (GFC) and optical non dispersive absorption (DOAS). A high stability sensor, working at a very low temperature (-35 °C) and the used technology ensure a nearly fully immunity to cross sensitivity, high stability and sensitivity.

A very powerful electronic unit that can acquire all available measures (4000 per second for each analyzed gas) reduces the noise to a minimum value.

The measuring principle, the optical bench and the automatic and accurate compensation of the variations of room temperature enable to avoid the expensive and complicated automatic calibrations, which are always possible.

A large back lighted graphic display continuously supplies the value of the measured gases (including a large bar graph), the alarms, the service requirements, the faults, separated for each gas and the alarms from the sampling system.

All alarms have the acknowledgement routine. All anomaly messages are reported on the display for the immediate knowledge of what has gone wrong. Contacts enable to retransmit all the diagnostic.

This instrument has been drawn to be user friendly and reduce as much as possible the costs of the analysis system in which it will be used. The analyzer can be directly connected to a P.C. provided with a special software, named DAS-DAC, for data acquisition.

APPLICATION

The analyzer can be used for gas measuring in a wild range of industrial applications:

·         Combustion control

·         Measuring of emissions of boilers, furnaces, domestic and industrial incinerators, cement, furnaces, etc.

·         Process gas

·         Monitoring of emissions of engines and test bench

·         Analysis of gases from

·         Air quality in green houses, tunnels, parking

·         Analysis of protection atmosphere

PRINCIPLE OF OPERATION

A wide band infrared radiation is emitted by a non metallic, high stability source. For each measured gas this radiation is routed alternatively through an interferential filter and a cuvette filled with nitrogen and a filter and a cuvette filled with high partial pressure of the gas to be analyzed.

A suitable optical system drives the IR radiation inside the analysis chamber and then to the detector which receives and amplifies alternatively the two signals: one is the measure, the other is the measure. The gas concentration is proportional to the difference of the two signals.

Gases which may have a cross sensitivity with the measured gas, generate the same variation of the measure and reference signals. Therefore the measure is not affected. 

The wheel that holds the cuvettes and filters rotates at 3000 r.p.m. The sensor can acquire 50 measures each time one of the cuvettes is in front of the IR. source. A high quantity of measures is available. They must be amplified and computed, having a very high precision and stability.

Two microprocessors connected via a dual ram are used. With this approach no measures are lost and the instrument can manage all functions. The analyzer can be optionally provided with an electrochemical cell for O2 measuring.

FUNCTIONAL DESCRIPTION

The analyzer is housed in a metallic enclosure suitable for 19” 3 PV mounting. The electronic circuit is placed on the rear part of the housing. All connectors for input and output signals are directly welded in the printed circuit, avoiding wire and connectors inside the housing. On the rear part are also placed the filtered plug with switch and fuses for the main power supply and the inox pneumatic connections for gas inputs and outputs. Inside the housing are present a membrane pump, the electro valve for the auto zero calibration, a flow sensor and the optional cell for O2 measuring. The panel includes a 16 keys keyboard, a fine filter with the visible filtering element and the back lighted display

DPB Version

Polluting compound and emissions measure the more and more reduced in the air, have demanded the reduction of the full-scale of the instrument in order to render the measure of more and more small analyzable gas amounts possible.  Version DPB differs from the base version for the fact that uses an optical path much longer with consequent increase of the variation of  measure signal with the same gas concentration. Is therefore possible to reduce drastically  the full-scale of measurable gases.  Particular attention has been placed in the measure of CO and CO2 in air or in the products of combustion obtaining:

All the other characteristics remain unchanged;  only the weight increases of 1.1 Kg.  

Technical specifications