Analytical-industries GPR-35 Oxygen Analyzer Manuel d'utilisateur télécharger pdf (Page 8)

Advanced Instruments Inc.

¾ Assure there are no restrictions in the sample or vent lines

¾ Avoid drawing a vacuum that exceeds 14” of water column pressure – unless done gradually

¾ Avoid excessive flow rates above 5 SCFH which generate backpressure on the sensor.

¾ Avoid sudden releases of backpressure that can severely damage the sensor.

¾ Avoid the collection of liquids or particulates on the sensor, they block the diffusion of

oxygen into the sensor - wipe away.

¾ If the analyzer is equipped with an optional integral sampling pump (positioned

downstream of the sensor) and a flow control metering valve (positioned upstream of the

sensor), completely open the flow control metering valve to avoid drawing a vacuum on

the sensor and placing an undue burden on the pump.

¾ Calibrate ambient area monitors with a certified span gas.

¾ Avoid calibration of ambient area monitors with the surrounding atmosphere unless

assured the oxygen content is 20.9%.

¾ Optionally, to confirm the span gas calibration or air calibration of the GPR-35, the user can

use an inexpensive battery powered hand held analyzer (such as the AII-3000A pictured at

right) that is easily air calibrated in a “safe remote area” and carried to the area being

monitored by the GPR-35 where readings can be compared.

Moisture & Particulates: Installation of a suitable coalescing or particulate filter is required

to remove condensation, moisture and/or particulates from the sample gas to prevent

erroneous analysis readings and damage to the sensor or optional components. Moisture and/or particulates do not necessarily

damage the sensor, however, collection on the sensing surface can block or inhibit the diffusion of sample gas into the sensor

resulting in a reduction of sensor signal output – and the appearance of a sensor failure when in fact the problem is easily

remedied by blowing on the front of the sensor. Consult the factory for recommendations concerning the proper selection and

installation of components.

Moisture and/or particulates generally can be removed from the sensor by opening the sensor housing and either blowing on

the the sensing surface or gently wiping or brushing the sensing surface with damp cloth. Caution: Minimize the exposure of

ppm sensors to air during this cleaning process. Air calibration followed by purging with zero or a gas with a low ppm oxygen

concentration is recommended following the cleaning process. Moisture and/or particulates generally can be removed from the

sample system by flowing the purge gas through the analyzer at a flow rate of 4.5-5 SCFH for an hour.

Mounting: The analyzer is approved for indoor use, outdoor use requires optional enclosures, consult factory. Mount as

recommended by the manufacturer.

Gas Connections: Analyzers designed for in-situ ambient or area monitoring have no sample system because the sensor is

intended to be exposed directly to the surrounding ambient atmosphere which it is sampling and to operate at atmospheric

pressure, however, slightly positive pressure has minimal effect on accuracy. Further, applications situations may dictate that

the sample be transported from a semi-sealed area to a safe area where the analyzer is located. In these cases the analyzer can

be readily adapted to include optional pumps, tubing and connection fittings.

Power: Supply power to the analyzer only as rated by the specification or markings on the analyzer enclosure. The wiring that

connects the analyzer to the power source should be installed in accordance with recognized electrical standards. Ensure that is

properly grounded and meets the requirements for area classification. Never yank wiring to remove it from a terminal

connection. AC powered analog analyzers consume 5 watts.

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Analytical-industries GPR-35 Oxygen Analyzer Manuel d'utilisateur Page 8