Multi functional desktop dissolved oxygen analyzer

Multi functional desktop dissolved oxygen analyzerInstrument features:
1. The dissolved oxygen measurement mode has the functions of automatic temperature compensation, automatic salinity compensation, and automatic pressure compensation.
2. The new structure of the polarographic dissolved oxygen electrode can simultaneously measure temperature, salinity, and dissolved oxygen, and is equipped with a dissolved oxygen electrode calibration kit
Polarization only takes 3-5 minutes.
4. Compliant with international GLP requirements, it has intelligent functions such as automatic calibration, data storage, RS232 output, clock display, and function settings.
5. There are three different measurement modes: stable display mode; Timed measurement mode; Continuous measurement mode.
6. Optional intelligent magnetic stirrer (dissolved oxygen measurement must be used in conjunction with a magnetic stirrer)
Instrument parameters:
name:Multi functional desktop dissolved oxygen analyzer
Model: JPSJ-605F
Measurement range: (0~20.00) mg/L (ppm) (0~200.0)%
Resolution: 0.1/0.01 mg/L (ppm) 1/0.1%
Accuracy: Electrometer: ± 0.10 mg/L, matching: ± 0.40 mg/L
Response time: ≤ 30 seconds (25 ℃, 90% response)
Residual current: ≤ 0.1 mg/L
Temperature compensation range: 0~45 ℃ (automatic)
Salinity compensation range: (0~45) ppt (automatic)
Pressure compensation range: (80~105) kPa (automatic)
Automatic calibration: air saturated with water; Water saturated with air
Electrode type: Polarographic
Measurement range: -10 ℃~110 ℃
Resolution: 0.1 ℃
Accuracy: 5~60 ℃ Range: ± 0.4 ℃ Other ranges: ± 0.8 ℃
Data storage: 600 sets
Storage contents: measurement value number, measurement value, temperature value, measurement date, measurement time
Power supply: DC9V/300mA
Communication interface: RS232
Environmental temperature: 10-30 ℃
Environmental humidity: ≤ 80%
IP rating: IP54 dustproof and splash proof
working principle
The oxygen content in water can fully demonstrate the degree of self purification of water. For biological treatment plants using activated sludge, it is crucial to understand the oxygen content in the aeration tank. An increase in dissolved oxygen in wastewater can promote biological activities other than anaerobic microorganisms, thereby removing volatile substances and easily oxidizable ions, and purifying the wastewater.
There are three main methods for measuring oxygen content: automatic colorimetric analysis and chemical analysis measurement, paramagnetic method measurement, electrochemical method measurement, and fluorescence method. The dissolved oxygen in water is generally measured by electrochemical method.
Oxygen can dissolve in water, and its solubility depends on temperature, total and partial pressure on the water surface, and the salts dissolved in the water. The higher the atmospheric pressure, the greater the ability of water to dissolve oxygen, which is determined by Henry's law and Dalton's law. Henry's law states that the solubility of a gas is proportional to its partial pressure.
The oxygen measurement sensor consists of a cathode (usually made of gold and platinum), a current carrying counter electrode (silver), and a reference electrode (silver) without current. The electrode is immersed in electrolytes such as KCl and KOH. The sensor is covered with a diaphragm, which separates the electrode and electrolyte from the measured liquid. Only dissolved gases can penetrate the diaphragm, thus protecting the sensor from electrolyte leakage and preventing contamination and poisoning caused by foreign substances.
Applying a polarization voltage between the counter electrode and the cathode, if the measuring element is immersed in water with dissolved oxygen, oxygen will diffuse through the membrane, and oxygen molecules appearing on the cathode (excess electrons) will be reduced to hydroxide ions [OH -]. Electrochemical equivalent silver chloride precipitates on the counter electrode (electron deficient). For each oxygen molecule, the cathode releases 4 electrons and the counter electrode accepts electrons, forming a current of 4Ag+4Cl -=4AgCl+4e -.
The current is proportional to the oxygen partial pressure of the sewage to be measured. This signal, together with the temperature signal measured by the thermal resistance on the sensor, is sent to the transmitter. The oxygen content in the water is calculated using the relationship curve between the oxygen content, oxygen partial pressure and temperature stored in the sensor, and then converted into standard signal output. The function of a reference electrode is to determine the cathodic potential.