Industrial Online Residual Chlorine Sensor

Working Principle

Electrolyte and osmotic membrane separates the electrolytic cell and water samples, permeable membranes can selectively to ClO- penetration; between the two

electrode has a fixed potential difference, current intensity generated can be converted into residual chlorine concentration.

At the cathode: ClO^- + 2H+ + 2e^- → Cl^-+ H₂O

At the anode: Cl^- + Ag → AgCl + e^-

Because in a certain temperature and pH conditions, HOCl, ClO- and residual chlorine between fixed conversion relationship, in this way can measure the residual chlorine.

Technical Indexes

Daily Maintenance

(1) Such as the discovery of the whole measurement system long response time, membrane rupture, no chlorine in the media, and so on, it is necessary to replace the membrane, the maintenance of the electrolyte replacement. After each exchange membrane or electrolyte, the electrode needs to be repolarized and calibrated.

(2) The flow rate of the influent water sample is kept constant;

(3) The cable shall be kept in a clean, dry or water inlet.

(4) Instrument display value and the actual value vary greatly or chlorine residual value is zero, may dry chlorine electrode in the electrolyte, the need to re injection into the electrolyte. Specific steps are as follows:

Unscrew the electrode head film head (Note: absolutely not to damage the breathable film), drained the film first before the electrolyte, then the new electrolyte poured into the film first. General every 3 months to add the electrolyte, half a year for a film head. After changing the electrolyte or the membrane head, the electrode is required to be re - calibrated.

(5) Electrode polarization: the electrode cap is removed, and the electrode is connected to the instrument, and the electrode is more than 6 hours after the electrode is polarized.

(6) When not using the site for long time without water or meter long time, should promptly remove the electrode, sheathe a protection cap.

(7) If the electrode fails to change the electrode.

What's Means Residual Chlorine?

Residual chlorine is the low level amount of chlorine remaining in the water after a certain period or contact time after its initial application. It constitutes an important safeguard against the risk of subsequent microbial contamination after treatment—a unique and significant benefit for public health. Chlorine is a relatively cheap and readily available chemical that, when dissolved in clear water in sufficient quantities, will destroy most disease causing organisms without being a danger to people. The chlorine, however, is used up as organisms are destroyed. If enough chlorine is added, there will be some left in the water after all the organisms have been destroyed, this is called free chlorine. (Figure 1) Free chlorine will remain in the water until it is either lost to the outside world or used up destroying new contamination. Therefore, if we test water and find that there is still some free chlorine left, it proves that most dangerous organisms in the water have been removed and it is safe to drink. We call this measuring the chlorine residual. Measuring the chlorine residual in a water supply is a simple but important method of checking that the water that is being delivered is safe to drink.