Conductance is the ability of the solution to conduct electric current. A: The effect of temperature on conductivity readings depends on the solution being measured. The effect is greatest in low ionic strength low conductivity solutions.
This rule can be followed for most aqueous solutions, however if you require a high degree of accuracy, you should consult a chart for the particular solution you are measuring. A: No, all substances possess some conductive properties. Generally organic compounds such as benzene, alcohols, and petroleum products have very low conductivities, while metals have very high conductivities.
Measuring the conductivity of highly flammable liquids is very risky. A: Salts, minerals, and even dissolved gases contribute uniformly to the conductivity of a solution. Shown here is a conductivity meter being used to measure the quality of water in a wastewater treatment facility. In addition to conductivity, this particular meter can be used to measure pH and dissolved oxygen. Shown here is a conductivity meter that can measure the conductance of up to samples of plant material and analyze the measurements with available data processing equipment.
Damage to plant cellular membranes is a common response to a stress. This damage leads to leakage of electrolytes from the cells of stressed tissues. By measuring this leakage with a conductivity meter, an operator can reliably indicate the severity of the stress on a plant. Hach Company , Loveland, CO. Hanson, B. McPherson, Lori. McPherson Lori. The reading of a conductivity meter is usually without a temperature correlation.
Since ionic strength, and therefore conductance, is temperature-dependent, the reading may be inaccurate. Thus, many conductivity meters have a specific conductance measurement as well. When in the specific conductance mode, the meter reads the conductivity of the solution at 25 degrees Celsius, not at the actual temperature.
This results in a more standardized reading. Salinity is the amount of dissolved salts in a solution. Conductivity meters equipped with a salinity option internally convert the conductivity reading to one of salinity. Total dissolved solids can be determined by multiplying the conductivity measured in microSeimens by a factor of 0.
Calibration leads to a more accurate reading. To calibrate a meter, follow the instructions for that meter; in general, the steps are easy and standardized. Conductivity varies greatly with temperature change and the readings must be corrected for the affect of temperature. Usually the conductivity meter has an in-built thermometer that automatically compensates for the temperature effects and presents an accurate reading.
The meter can be adjusted to bring it to the correct reading and then put back into service. An alternative to direct liquid contact type probes, is to use induced electrical field conductivity probes.
These probes generate an alternating current electro-magnetic filed in the liquid. Charged particles in the liquid respond by setting-up a counter acting electro-magnetic field that is detected by the probe.
The strength of the field generated in the liquid reflects the conductivity of the water. No direct contact with the solution is required. The sensor end of the probe is mounted in the water stream and the read-out is displayed locally or in a control room. Conductivity meters are regularly installed in boiler water purification plants to prove the treatment is removing the dissolved salts and metals that would otherwise go into the boiler and scale-up the heat transferring metal surfaces.
Conductivity meters are also used to measure the TDS build-up inside boilers and to automatically open and close a control valve to blow down the boiler contents and lower the TDS. The probe senses the contamination increasing as water is boiled away into steam.
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