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Chlorine Analyzer – AMI codes II
Chlorine is often added into the treatment process for potable waters. For ultrapure waters chlorine must be removed in a process called dechlorination. For this purpose a very low reading analyser with absolutely no drift is needed. Arasains Indonesia supplies the AMI Codes II for measuring low levels of chlorine in semiconductor waters. This instrument uses a colorimetric process analyser using the DPD method according to EN ISO 7393-2 and APHA 4500 CI-G methodologies. The measurement values can be configured to read free chlorine, total chlorine, chlorine dioxide bromine or iodine, monochloro amines or ozone. The analyser is a complete system including measurement and control electronics, photometer, flow indicator, reaction chambers reagent dosing system and reagent containers. For cleaning of the photometer and reaction chambers, a chemical cleaning moduleis available. pH is an integrated measurement together with temperature. The measurement range is 0-2 ppm chlorine with an accuracy of 0.02 ppm. The cycle time is 1 to 12 minutes. Communications channels are 4-20 mA output, rs 485, profibus DP or Modbus with a logger download kit with hyper terminal.
Conductivity Swan Rescon
High purity waters measures conductivity/resistivity at the lower limits of measurement. It is thus important that a suitable analyser is selected. Swan Rescon is specifically designed to measure semiconductor waters of 0.055mS/cm using a high precision resistivity sensor, Swan sensor RC-U, a two wire electrode made of stainless steel with integrated precision temperature probe. The transmitter is housed in an aluminium enclosure of IP 66. For monitoring of flow, a flow sensor, QV-Flow with needle valve is available with a digital flow reading. In order to maintain stable reading throughout its life time, the instrument regularly conducts its own verification with an on board ultra high precision resistors. For calibration an optional precision test resistor plug for transmitter verification according to USP645 can be supplied by Arasains Indonesia. The precision sensor has a certificate with a cell constant defined with a precision of 5 digits after the decimal point. The temperature correction factor for the built in NTC is determined with a thermometer traceable to national standards (Swiss National calibration service, 1997 SCS). The instrument is factory tested, calibrated and ready for use.
For pharmaceutical waters sensors with polished surface, sanitary flange and no dead volume according to 3A standards is available.
Silica is one of the most important parameters to be measured in a semicon plant. Swan Indonesia supply the AMI silica analyser for measurements of silica at ppb levels. The reproducibility is 1 ppb or ±5% of reading. This analyser is specially designed for measurements at low levels with a range of 1-5000ppb. The technology is based on colorimetric measurement. The analyser is a complete system including measurement and control electronics, photometer, flow indicator, reaction chambers reagent dosing system and reagent containers. The cycle time for each analysis is 10 mins. For cleaning of the photometer and reaction chambers, a chemical cleaning module is available. A second stream is available with a switching valve as an option. A sample sequencer for up to 6 streams is available as an accessory.
Other Parameters for Ultra Pure Water
Other parameters available for use in semiconductor plants are oxygen, boiler water analyzer and to pharmaceutical waters
FREQUENTLY ASKED QUESTIONS
Why is the measurement of pH important for the accurate measurement of free chlorine?
The amount of available chlorine for disinfection depends on the dissociation of HOCl and this is dependent on pH. As chlorine dissolves in water it forms hypochlorous acid. At high pH the hypochlorite ion is formed and this change from hypochlorous acid to the ion is rapid at pH 7-8. The effectiveness of disinfection depends on the hypochlorite ion.
Why is the measurement of silica important in ultra pure water?
Besides the importance of silica as a pollutant in semicon manufacture, silica analysis is important in prediction the exhaustion of resin columns. Normally conductivity can be used for monitoring this but the response may be too late. This is because silica is the first contaminant to be flushed out of the column. Monitoring this will then give you early warning ahead of conductivity.
For more information on the above tests contact the friendly Arasains sales staff or fill in the enquiry form.
For more questions ask Dr Lee
Caution : not all question can or will be answered