What is liquid conductivity?
Liquid conductivity refers to the ability of a liquid to conduct an electrical current. It is a measure of the liquid's ability to allow the flow of charged particles, such as ions, through it when an electric field is applied.
In essence, when it comes to flow measurement, it is the property of the liquids electrical resistance that is evidenced in an increase or decrease in speed when moving through a pipe that contains a magnetic field. Conductivity is typically expressed in units of siemens per meter (S/m) or microsiemens per centimeter (µS/cm).
The conductivity of a liquid is influenced by the presence and concentration of charged particles or electrolytes dissolved in the liquid. These particles can be ions from salts, acids, bases, or other dissolved substances. When an electric field is applied, the ions move towards oppositely charged electrodes, which creates an electrical current.
Why does the conductivity of a liquid matter for flow measurement and level control?
Certain flow and level technology types are not suitable for liquids with low conductivity. The actual principle of operation depends on the base assumption that the media being measured contains enough conductivity to carry an electrical current.
Magnetic flow meters are only suitable for liquids with sufficient conductivity. If you try to use a magnetic flow meter with a media like ultra-pure water, it will not work. To learn more about magnetic flow technology visit our article about Magnetic Flow Meters.
Conductive level switches also require a certain base level of conductivity because the principle of operation needs the media to be able to carry an electrical current for it to function properly.
How does temperature affect the conductivity of a liquid?
The conductivity of a liquid is often influenced by changes in temperature. As the temperature increases, the mobility of ions in the liquid may change, resulting in a change in conductivity. Any measurements of conductivity are often paired with temperature compensations to ensure accurate readings.
How do you measure the conductivity of a liquid?
The conductivity of a liquid can be measured using a conductivity meter or conductivity sensor. The sensor typically consists of two electrodes that are immersed in the liquid. When a voltage is applied across the electrodes, the resulting current is measured and used to calculate the liquid's conductivity.
What is total dissolved solids (TDS) in liquids and how does it relate to conductivity?
Total Dissolved Solids (TDS) refers to the content of both inorganic and organic substances within a liquid. There is a correlation between conductivity and TDS, although it is not a direct conversion and conductivity measurements can be used as an estimation of TDS levels in certain cases.
How does liquid conductivity relate to the salinity of water?
For bodies of water, conductivity is often used as a proxy for salinity. The more dissolved salts or ions that are in the water, the higher its conductivity is. This property is used to measure the salinity of water in applications such as environmental monitoring, aquaculture, and water treatment.
What Now?
Still confused about how the conductivity of your media affects choosing the right flow or level instrumentation for your application? Our expert engineers are available by phone or email to help you identify the best solution for your process or system.
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