How to use the conductivity meter

Speaking of conductivity meters, those who generally do instrumentation may not necessarily get them, but for those in the water treatment and environmental protection industries, they are certainly not unfamiliar. This is a parameter that often needs to be measured. But even if you don't touch it, after all, if you don't have enough skills, learn and understand more knowledge, you might be able to use it just by turning your head. The following is a detailed explanation of the knowledge for everyone: 　　What is conductivity? What is conductivity? Can you fish? Can it be discharged? Ah, will you get an electric shock! 　　 In fact, don’t worry! The strength of the conductor's ability to transmit current. The unit is Siemens (Siemens), abbreviated as West, and the symbol is S.　　2. Conductivity, a concept in physics, means that the product of the quantity and the electric field strength in the medium is equal to the conduction current density. For isotropic media, conductivity is a scalar; for anisotropic media, conductivity is a tensor. In ecology, conductivity is the ability of a solution to conduct electric current expressed as a number. The unit is expressed in Siemens per meter (S/m).　　 3. Conductivity is the reciprocal of resistivity.　　二　　Why measure it? 　　The measurement of conductivity is usually for the conductivity of the solution. The detection of the conductivity can qualitatively reflect the good condition of the water quality. High conductivity often corresponds to a larger ion concentration in the solution. Our general water is nearly neutral. Natural mineral water is the healthiest water for the human body. Like mineral water bought at ordinary times, it contains certain mineral ions and will exist. Certain electrolytes are good for human health.　　Water hardness detection　　In addition, if there are more calcium and magnesium ions in the water, the conductivity will be large, which is generally said to be high hardness. There is no serious impact in normal times, but it will affect the structure of the boiler. You might say that scaling is scaling. Let me give you an example of a power plant: 　　 There are generator sets in a power plant, and cooling water is often needed to control the temperature. However, there are certain requirements for the cooling water, which often requires processes such as deoxygenation and desalination before it can be recycled. But how to judge the effect of deoxygenation and desalination? At this time, it is often necessary to monitor water quality parameters, such as conductivity, pH, sodium ion, fluoride ion, etc., only when these parameters meet the requirements can it be recycled. If the oxygen is removed, the salt removal effect will not meet the requirements, and the water will scale when burned in the boiler, which will easily cause the boiler to explode. So it is very important to measure the conductivity. Environmental water quality testing of natural water bodies such as rivers and lakes. The water itself contains certain ions and has a certain range of electrical conductivity. If the electrical conductivity of the natural water body suddenly rises on a certain day, it indicates that the salt value in the water body is relatively high, and it may be affected by some The pollution of inorganic salt ions can reflect the water quality to a certain extent. 3. How to measure? 　　——————The general trend, the homeopathic conductivity meter and conductivity electrode test principle ), put it in the measured solution, add a certain potential to both ends of the electrode plate (in order to avoid solution electrolysis, it is usually a sine wave voltage with a frequency of 1 to 3 kHz). Then measure the conductance between the plates by a conductivity meter. Electrode classification (1) The two-electrode conductivity electrode is currently the most widely used type of conductivity electrode in China. The structure of the experimental two-electrode conductivity electrode is to sinter two platinum sheets on two parallel glass sheets, or on the inner wall of a round glass tube , Adjusting the area and distance of the platinum sheet, conductivity electrodes with different constant values u200bu200bcan be made. Usually there are Ku003d1, Ku003d5, Ku003d10 and other types. The two-electrode conductivity electrode used on the online conductivity meter is often made into a cylindrical symmetrical electrode. When Ku003d1, graphite is often used, when Ku003d0.1, 0.01, the material can be stainless steel or titanium alloy.　　(2) Multi-electrode type conductivity electrode. Generally, there are several ring-shaped electrodes on the support. Through different combinations of ring-shaped electrodes in series and parallel, conductivity electrodes with different constants can be made. The material of the ring electrode can be graphite, stainless steel, titanium alloy and platinum. There are four-electrode type and electromagnetic type for conductivity electrodes.　　Electrode installation method　　Installation precautions　　(1) The electrode should be installed in the pipeline at a low position, stable flow rate and not easy to generate bubbles.　　 (2) The concentric tubular electrode should be installed in the direction of FLOW in flat, oblique or vertical installation, and should go deep into the movable water body.　　 (3) The measurement signal is a weak electrical signal. The collection cable should be routed independently. It is forbidden to connect with the power line and control line in the same set of cable connectors or terminal boards to avoid interference or breakdown of the measurement unit.