Signal NOXGEN III Operation Manual Download Page 5

SIGNAL GROUP LTD 

 

s/sales/masters/manuals/noxgman.doc                                                      Page 5 of 17

 

2.00 

INTRODUCTION

 

 
Chemiluminescent NOx analysers, such as Signal’s own Model 4000 Series; rely 
upon the efficiency of the NO2 to NO converter in the analyser.  The converter 
enables a measurement to be made of the total oxides of nitrogen in the sample 
stream (NOx = NO + NO2). 
 
The 1979 Heavy Duty Register of the U.S. Environmental Protection Agency 
stipulates that such converters must be checked before the analyser is initially 
used, and thereafter at weekly intervals, to ensure that they have an efficiency of 
at least 90%.  The Signal NOXGEN III provides known, accurate amounts of NO2 
for converter efficiency testing, and fully meets the EPA requirements. 
 
The instrument is compact, inexpensive and provides a precision of control and 
repeatability of results that were unobtainable with the previous generation of 
converter testers.  Ozone is generated by a high energy lamp using an electronic 
pulse, which can be varied to adjust the Ozone level.  The Noxgen III produces no 
NO from air, in contrast to the high voltage corona discharge technique. 
 
Stability against mains power variations, and the consequent effects of NO2 
concentrations, is ensured by the incorporation of a voltage stabilised electronic 
circuit, feeding pulses to a high voltage transformer. 
 
2.01 

PRINCIPLES OF OPERATION

 

 
The instrument is fed with nitric oxide and oxygen, the latter being subjected to a 
high-energy lamp, which partially converts the oxygen to ozone.  The 
oxygen/ozone mixture is passed to the nitric oxide flow, and the nitric oxide is 
instantly converted by the ozone to give nitrogen dioxide.  The reaction between 
the remaining oxygen and nitric oxide again produces nitrogen dioxide, but this 
reaction is so slow that it does not need to be taken into account for test 
purposes. 
 
The amount of nitrogen dioxide generated is determined by measuring the fall of 
nitric oxide concentration.  If, for example, this concentration falls by 400 vpm, 
then 400 vpm nitrogen dioxide has correspondingly been generated, as the 
oxidation is a 1 : 1 molecular reaction.  The concentration of nitrogen dioxide is 
therefore directly proportional to the concentration of ozone generated.  When 
connected to the analyser converter, the NO2, should be converted back to NO.  
From the results obtained the converter efficiency can be determined. 

Summary of Contents for NOXGEN III

Page 1: ...doc Page 1 of 17 SIGNAL NOXGEN III NO2 CONVERTER TESTER OPERATION MANUAL NOX III MAN SIGNAL GROUP LTD 12 Doman Road Camberley Surrey GU15 3DW UK Tel 44 0 1276 682841 Fax 44 0 1276 691302 e mail instru...

Page 2: ...Group Ltd While we believe that the information and guidance given in this manual is correct all parties must rely upon their own skill and judgement when making use of it The Signal Group Ltd will n...

Page 3: ...4 2 02 The Ozonizer 5 2 03 Flow Scheme Diagram 6 2 04 Remote Control Flow Scheme Diagram 7 3 00 INSTALLATION 8 3 01 General 8 3 02 Installation Drawing 9 3 03 Span Gas Connection 10 3 04 Oxygen Air In...

Page 4: ...ce or Distributor 1 Before any connection is made unscrew the 4 cross head screws on instrument cover lid 2 Slide lid back to reveal the internal assemblies of the instrument NOTE Do not take the cove...

Page 5: ...e corona discharge technique Stability against mains power variations and the consequent effects of NO2 concentrations is ensured by the incorporation of a voltage stabilised electronic circuit feedin...

Page 6: ...NOXGEN III utilises a very efficient high energy lamp system which ionises oxygen to ozone The ozonizer is built into a fully self contained enclosure within the instrument This should not be opened...

Page 7: ...SIGNAL GROUP LTD s sales masters manuals noxgman doc Page 7 of 17 Figure 2 03 Flow Scheme Diagram...

Page 8: ...SIGNAL GROUP LTD s sales masters manuals noxgman doc Page 8 of 17 Figure 2 04 Remote Control Flow Scheme Diagram...

Page 9: ...t will need to be removed To do this undo the 4 cross head screws on the under cover and slide back the cover to remove it With the cover removed you can easily unscrew the four feet before replacing...

Page 10: ...SIGNAL GROUP LTD s sales masters manuals noxgman doc Page 10 of 17 Figure 3 02 Installation Diagram...

Page 11: ...but dry air can be used with almost as high an ozone production as that using oxygen Also the Signal Model NOXGEN III has been carefully designed so that no nitric oxide is generated from the nitroge...

Page 12: ...ny of the function pins can be utilised the remote enable must be operated and again either an OV logic signals via the earth return or a short circuit wire link can be used Without the remote enable...

Page 13: ...SIGNAL GROUP LTD s sales masters manuals noxgman doc Page 13 of 17 Figure 4 00 Operational Controls...

Page 14: ...ygen ON OFF flow valve on the Noxgen front panel G and adjust the flow of this oxygen using the flow control I until the analyser reading falls by about 10 of the original reading in step 6 Record thi...

Page 15: ...the analyser reading This reading should now represent the same as obtained in Step 6 The only difference now from Step 6 is that you have the analyser in its NOx mode and therefore any NO2 which was...

Page 16: ...e enable control is activated the instrument will behave the same as the standard manual controlled Noxgen and the operation as explained in Steps 1 11 can be carried out as normal With power off all...

Page 17: ...SIGNAL GROUP LTD s sales masters manuals noxgman doc Page 17 of 17 Figure 4 02 Chart Display...

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