Operating manual ConOx Combined Conductivity and Dissolved Oxygen Sensor ba75383e03 10/2004
ConOx Accuracy when going to press Copyright The use of advanced technology and the high quality standard of our instruments are the result of continuous development. This may result in differences between this operating manual and your instrument. Also, we cannot guarantee that there are absolutely no errors in this manual. Therefore, we are sure you will understand that we cannot accept any legal claims resulting from the data, figures or descriptions.
ConOx Contents ConOx - List of contents 1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.1 1.2 Structure and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Instrument identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview ConOx 1 Overview 1.1 Structure and function The ConOx is a modular sensor for conductivity, dissolved oxygen (DO) and temperature.
ConOx Overview The conductivity basic module can be used as an independent conductivity measuring cell. For this purpose, unscrew the DO module and close the open plug connection with a closing cap. The DO module is connected to the conductivity basic module via a watertight, three-pole plug connection. The conductivity basic module measures the temperature, which is required for the determination of the DO content.
Safety ConOx 2 Safety This operating manual contains special instructions that must be followed during the operation of the sensor. Always keep this operating manual in the vicinity of the sensor. Special user qualifications The membrane cap of the DO module is filled with a small amount of an alkaline electrolyte solution. All maintenance work that requires dealing with the electrolyte solution must only be carried out by persons who know how to deal with chemicals safely.
ConOx Commissioning 3.1.2 Scope of delivery of the conductivity basic module l Conductivity basic module l 1 closing cap, mounted on the conductivity basic module l Operating manual for ConOx 3.1.
Commissioning ConOx 3.2 Getting the sensor ready for measuring 3.2.1 Measurements with the conductivity basic module Make sure that the plug connection is tightly closed by the closing cap. When mounted, the closing cap (1) must be screwed on up to the stop. 1 2 Before screwing on the closing cap, check the following points: l The sealing (2) must be clean and evenly positioned in the groove. l The plug connection and the inside of the closing cap must be clean. 3.2.
ConOx Unscrewing the DO module Measuring / Operation Unscrew the cap nut and remove the DO module from the conductivity basic module. Caution Inappropriate handling can lead to the release of electrolyte solution. When unscrewing the DO module only turn the cap nut (not the membrane cap!). 3.2.3 Preparing the measuring operation Connect the sensor to the measuring instrument. The sensor is immediately ready to measure. It is not necessary to polarize the DO module. 4 Measuring / Operation 4.
Maintenance, cleaning, replacement 4.3 ConOx Storage Always store the sensor with the DO module in the calibration vessel at a temperature of 0 to +50 °C. Make sure that the sponge in the calibration vessel is always moist. 1 Storage in the calibration vessel, OxiCal®-CX 2 Moisten the sponge: l Remove the cap (1). l Take out the sponge (2), wet it, then slightly squeeze it out. l Reinsert the sponge and close the calibration vessel with the cap.
ConOx Maintenance, cleaning, replacement Caution The RL/G cleaning solution irritates eyes and skin. When dealing with the RL/G cleaning solution, observe the following points: l During working activities, always wear suitable protective gloves and protective goggles/face shield. l If it comes into contact with the skin, rinse thoroughly with water and immediately change contaminated clothing. l If it comes into contact with the eyes, rinse thoroughly with water and consult a doctor.
Maintenance, cleaning, replacement 5.3 ConOx DO module: Changing the electrolyte solution and membrane cap Caution Before starting to work with the sensor, please note the GENERAL MAINTENANCE INSTRUCTIONS on page 34. General information WTW delivers the DO module ready to use (see section 3). The electrolyte solution and the membrane cap must only be replaced if: l a calibration error occurs and the membrane is heavily contaminated l the membrane is damaged l the electrolyte solution is exhausted.
Maintenance, cleaning, replacement G ELY/ ConOx ELY/ G Carefully shake off the drops of water. Fill a new membrane cap with ELY/G electrolyte solution. Remove any air bubbles by carefully tapping the membrane cap. Additionally, you can prevent air bubbles by throwing the first filling away and refilling the membrane cap. Ventilation area points upwards 4 mm Thoroughly rinse the sensor head with electrolyte solution.
Maintenance, cleaning, replacement 5.4 ConOx DO module: Cleaning the electrodes Caution Before starting to work with the sensor, please note the GENERAL MAINTENANCE INSTRUCTIONS on page 34. General information Cleaning is only required in cases of slopes too small or too large (sensor cannot be calibrated) that cannot be resolved by changing the membrane cap and electrolyte solution. Cleaning the electrodes SF 300 Unscrew the membrane cap.
ConOx Maintenance, cleaning, replacement H2O Carefully shake off the drops of water. Remove any air bubbles by carefully tapping the membrane cap. Additionally, you can prevent air bubbles by throwing the first filling away and refilling the membrane cap. Rinse the sensor head with electrolyte solution. G Water the counter electrode in deionized water for at least 10 minutes. ELY/ ELY/ G Thoroughly rinse the sensor head with deionized water.
Maintenance, cleaning, replacement ConOx Note For measurements under high pressure the filling must be completely free of air bubbles. Readiness to measure After approx. 30 to 50 minutes, the sensor is ready for operation. Subsequently calibrate the sensor. Note If you want to measure very low DO concentrations (< 0.5 % saturation), we recommend to let the sensor rest overnight and then calibrate it. 5.5 Checking the DO module for freedom from zero-current The DO module is free from zero-current.
ConOx Maintenance, cleaning, replacement 5.7 Disposal Caution The ELY/G electrolyte solution irritates eyes and skin. When dealing with the ELY/G electrolyte solution, observe the following points: l During working activities, always wear suitable protective gloves and protective goggles/face shield. l If it comes into contact with the skin, rinse thoroughly with water and immediately change contaminated clothing.
What to do if... ConOx 6 What to do if... 6.1 Error symptoms of DO measurement Error symptom Cause The sensor is in the air and the display shows 0.0 mg/l or 0 % O2 – No connection between – Check connection between measuring instrument and sensor measuring instrument and sensor – Cable defective – No electrolyte in the membrane – Replace and refill the membrane cap cap (see section 5.
ConOx Technical data General features 7 Technical data 7.1 Conductivity basic module Measuring principle Four-electrode measurement Cell constant 0.475 cm-1 ±1.5 % Temperature sensor integrated NTC 30 (30 kW/ 25 °C) Dimensions (in mm) Weight Materials Connection cable Connector for DO module approx. 135 g (without DO module, with 1.
Technical data Pressure resistance ConOx Sensor with closed plug connection IP 68 (3 x 105 Pa or 3 bar) Cable plug IP 67 (when plugged in) The ConOx meets the requirements according to article 3(3) of the 97/23/EC directive ("Pressure equipment directive"). Measurement conditions Storage conditions Characteristic data on delivery Conductivity measuring range 1 mS/cm ... 2 S/cm Temperature range 0 ... 50 °C Max. allowed overpressure 3 x 105 Pa (3 bar) Depth of immersion min.
ConOx Technical data Materials Plug connection Pressure resistance Working electrode Gold Counter electrode Lead – Membrane cap – Cap nut POM Membrane FEP, 13 µm – Sensor head Epoxy, PEEK – Plug connection PEEK Screw thread base Stainless steel 1.
Technical data Characteristic data on delivery Pin assignment ConOx Zero signal < 0.1 % of the saturation value Response time at 20 °C t90 (90 % of the final value display after) < 10 s t95 (95 % of the final value display after) < 16 s t99 (99 % of the final value display after) < 60 s Oxygen own consumption at 20 °C 0.008 µg·h-1 (mg/l)-1 Drift approx. 3 % per month in the operating condition Working life min.
ConOx Wear parts and accessories 8 Wear parts and maintenance means Accessories Wear parts and accessories Description Model Order no.
Wear parts and accessories 48 ConOx
