Q: What is dissolved oxygen (O2)?
A: Dissolved oxygen is the level of free, non-compound oxygen, which is pr...
Q: What is dissolved oxygen (O2)?
A: Dissolved oxygen is the level of free, non-compound oxygen, which is present in water or another liquid. it is typically measured with an in-line dissolved oxygen analyzer.
Q: What is an in-line dissolved oxygen analyzer?
A: A dissolved oxygen analyzer is a system for in-line DO measurement. An in-line dissolved oxygen analyzer typically consists of three major components: a dissolved oxygen sensor, a dissolved oxygen transmitter (or multi-parameter transmitter) and a process adaption/housing system. The dissolved oxygen sensor typically used in a dissolved oxygen analyzer is typically is a sensor designed for industrial dissolved oxygen measurement, as opposed to laboratory measurement. In-line DO analyzers can use either optical dissolved oxygen sensors or polarographic dissolved oxygen sensors.
Q: Why is dissolved oxygen measured with an in-line DO analyzer?
A: Proper oxygen levels are important in many processes in biotechnology, pharmaceutical development, food and beverage production, chemical manufacturing and in water and primary water treatment. In-line DO analyzers are vital for optimizing product yield and quality, reducing costs and ensuring process safety.
Q: What does a dissolved oxygen analyzer display?
A: A METTLER TOLEDO dissolved oxygen meter measures in real-time and continuously the dissolved oxygen level in water or another liquid. Depending on the kind of application and industry, the dissolved oxygen concentration is expressed either in relative numbers, such as percent saturation, volume percent, percent dissolved oxygen, ppm or in absolute numbers, e.g. mg/L or mmol/L.
Q: How does an in-line dissolved oxygen analyzer work?
A: A dissolved oxygen analyzer (also called an in-line dissolved oxygen meter) works based on the technology of the industrial dissolved oxygen sensor. METTLER TOLEDO offers two different technologies of sensor for dissolved oxygen analyzers.: amperometric and optical.
Amperometric: The sensor for process dissolved oxygen analyzers uses a gas permeable membrane to separate the sample from the electrochemical cell inside. Oxygen diffuses through the membrane in direct proportion to the partial pressure of oxygen in the liquid outside the sensor. The cathode and anode inside the probe are polarized with a voltage to enable the electrochemical reaction of oxygen. Oxygen is reduced at the cathode while the anode is oxidized, producing a small current in direct proportion to the amount of oxygen reacting. In addition, the dissolved oxygen sensor uses the temperature value to convert the oxygen partial pressure signal to a dissolved oxygen concentration value by compensating for the changing solubility of oxygen with temperature.
Optical: Dissolved oxygen probes that use optical technology for measurement contain an oxygen-sensitive layer that can fluoresce. This layer absorbs light from a light emitting diode in the sensor, and the light is released as fluorescence. The amount of fluorescence depends on the level of oxygen present in the sample media.
Q: How do you calibrate a dissolved oxygen analyzer?
A: Each in-line DO analyzer has its own individual calibration parameter set which are subject to change. To ensure high measurement accuracy of the dissolved oxygen analyzer, calibration must be carried out after each exchange of a sensor's spare part(s). Dissolved oxygen sensor calibration can be performed as a 1-point or 2-point calibration. For the 1-point calibration the normal calibration medium is air, for a 2-point calibration additionally a gas with 0% oxygen has to be used, which normally is pure nitrogen.
Q: Are there in-line DO Analyzers with Intelligent Sensor Management (ISM)?
A: METTLER TOLEDO produces a wide range of ISM sensors for dissolved oxygen analyzers. These digital sensors provide you with the benefits of ISM on your in-line DO analyzer, including a strong digital signal to prevent signal interference so you can place your dissolved oxygen analyzer where you need it, predictive diagnostics on your sensor so that you know when your in-line DO sensor needs replacement parts or calibrated, and plug and measure technology that allows you to calibrate your sensor away from your in-line DO analyzer for fast sensor swapping.
