The supply of clean drinking water, and guaranteeing its quality and quantity, is becoming a more acute, important and costly issue. To record parameters from a body of water, in addition to the most commonly measured parameters such as determining the water level and temperature, other measured variables must also be determined, for example, conductivity. Conductivity is a good indicator of water cleanliness and an important parameter in the supply of drinking water.
Instrotech, the local supplier of Keller, a market leader in producing isolated pressure transducers and transmitters, has a CTD multiparameter probe and multiparameter logger that measures and monitors the quality and quantity of drinking water.
The acronym ‘CTD’ stands for conductivity, temperature and depth. These parameters are determined by the probe through a conductivity sensor, a PT1000 temperature sensor, and a pressure sensor. Since these parameters are directly dependent on each other, Keller incorporates three sensors into one device to provide compensated, and thus highly accurate, measured values.
Conductivity
Some media or substances, such as water, can transmit heat, sound or electricity. The more dissolved ions (chlorides, sulphates or carbonates) there are in a substance, the higher its electrical conductivity.
Thanks to the high number of dissolved ions, sea or salt water has a conductivity many times higher than conventional drinking or fresh water. Carefully distilled water, on the other hand, contains very few to zero dissolved ions, which prevents the flow of electrical current in the water.
Conductivity is determined by six titanium electrodes. The electrical current flow between the electrodes immersed in a medium is measured. The greater the current flow, the higher the conductivity. Conductivity sensors for water bodies measure from a few micro-siemens per cm (µS/cm) to about 200 milli-siemens per cm (mS/cm).
Some example values are:
• Distilled water: 0,05 µS/cm to 1 µS/cm.
• Drinking water: 300 µS/cm to 800 µS/cm.
• Seawater: approximately 50 mS/cm.
Temperature
Temperature changes in a substance also mean a change in conductivity. This means that at higher temperatures, the number of dissolved ions and their mobility increases significantly, hence the conductivity increases.
The temperature can be read out as an independent measuring value, but Keller uses it to compensate for the other parameters. The PT1000 temperature sensor is located directly next to the titanium electrodes, so the temperature and conductivity are measured at the same point.
Depth
The water depth is determined by the difference between the surface and the immersion depth. In measurement technology, one refers to the so-called water column. For example, a water column of 10 m corresponds to a pressure difference of approximately 1 bar.
The application dictates which of two different measuring methods is used: absolute pressure (related to vacuum) or relative pressure (related to ambient pressure).
Keller’s 36XiW-CTD multiparameter probe series and DCX-22-CTD / DCX-22AA-CTD multiparameter loggers combine all the aforementioned measurements in one device.
Pressure sensors for hydrogen applications Instrotech
Pressure Measurement & Control
Keller manufactures isolated piezoresistive pressure sensors. The great advantage of the piezoresistive measuring principle is its high stability.
Read more...Cloud-based inventory management software Endress+Hauser South Africa
Level Measurement & Control
Netilion is an award-winning cloud-based IIoT ecosystem designed for industrial processes. It connects the physical and digital worlds to send valuable information from the field straight to your phone, tablet or other device.
Read more...Level sensing, conveyor control and grid resistors DRH Components
Editor's Choice Level Measurement & Control
DRH Components is a specialist electric component and systems supplier with a focus on the control of electric motors. As part of its wide variety of products, the company markets the entire Bindicator range. Bindicator manufactures sensors for dry bulk and liquid level measurement.
Read more...Wind turbines with smart sensors Instrotech
Motion Control & Drives
The wind’s usable kinetic energy increases with the wind speed. Wind turbines, therefore, use kinetic energy to generate torque and then rotational movement. The rotor, consisting of three rotor blades, ...
Read more...Infrared camera for condition monitoring and early fire detection Instrotech
Temperature Measurement
The Optris PI 640i thermal imager is the smallest measuring VGA infrared camera, with a body-sized volume of 45 x 56 x 90 mm, and weighing only 269 to 340 g, depending on the lens. It counts among the most compact thermal imaging cameras on the market.
Read more...Pressure monitoring for oil and water tempering machines Instrotech
Pressure Measurement & Control
Temperature plays a significant role in many manufacturing processes. In such cases, a tempering machine is used to maintain the manufacturing process at the desired temperature. Keller supplied PR-21Y piezoresistive pressure transmitters to a client specialising in developing and producing oil and water tempering machines.
Read more...Level measurement under extreme plant processing conditions VEGA Controls SA
Level Measurement & Control
Level measurement in LNG and LPG processes is about answering the simple question: “How much product is in the tank?” However, obtaining an exact value is not easy. The products are often under pressure, cryogenic, and highly explosive. Sensors from Vega have been operating successfully in all stages of the LNG/LPG process for many years.
Read more...Temperature monitoring in the metal casting process Instrotech
Temperature Measurement
During metal casting, the liquid material is poured into a mould, and after solidification becomes a solid body. Both too-high and too-low casting temperatures can lead to quality defects. The compact Optris PI 05M infrared thermal imaging camera from Instrotech can monitor the casting process.
Read more...Grounding of hydrostatic level sensors WIKA Instruments
Level Measurement & Control
Hydrostatic level sensors are very often installed in outdoor applications, primarily in the water and wastewater industries. A good connection to ground is essential when installing hydrostatic level sensors, since no grounding or poor grounding can result in destruction or damage to the level sensor.
Read more...Interference-resistant pressure transmitters Instrotech
Pressure Measurement & Control
Instrotech offers a pressure transmitter from Keller for temperature compensation and protection from electromagnetic fields (EMC) in the recently approved 21Y Series.
printer friendly version