Resistivity Meters

Resistivity Meters

The resistivity of water is a measure of the ability of water to resist electric current. Pure water has a resistivity of 18.104 milliohms (mΩ) at standard sea-level atmospheric pressure. Resistivity is not constant, but varies depending on temperature and the presence of solutes that may be electrolytes. The resistivity of water is one of the parameters used to determine the quality of a water source. The higher the resistance, the more are the contaminants in the water. In other words, high resistivity is a sign that there are either high levels of dissolved solids or contaminants like metal or grime.

Monitoring the water purity is a necessity for power generation, semiconductor manufacturing and other industries. The so-called resistivity meters rightly serve this purpose as they can be used to measure the quality of raw water, in-line with treatment plant process control, and after treatment. At Cannon Water Technology, we offer an extensive line of water resistivity meters that offer a relatively inexpensive way to measure water quality. When you opt to buy resistivity meter online, you get a chance to explore a wide variety of models and choose a one that best suits your requirements at a cost-effective price.

Working of Water Resistivity Meter

Water resistivity meter is a sophisticated device that measures the electrical properties of water and determines if it is pure or not. The device shows the presence of pollutants, and other physical or chemical impurities.

A water resistivity meter is made up of a transmitter, a receiver and an electronic circuit. The transmitter sends a current into the measuring cell through the transmitter wire. This current goes into the measuring cell and through the area that needs to be tested. The meter has a sensor that produces an electrical impulse and sends it to the water sample. A display then shows the amount of current that returns to the meter from the water sample. The information gathered is then used to determine the resistivity level of the water.

Beneficial Features of Resistivity Meters

Water resistivity meters are an effective and economical way to test water quality. They are great for homeowners and businesses alike, and can be used to perform a wide range of tests. A few amongst the well-known features of this tool offered by us are as follows:

  • This digital water resistivity meter has a clear 4 digit liquid crystal display, which allows easy reading in outdoors as well as in low-lit areas with the backlight. 
  • This hand-held device can be used for both indoor and outdoor use.
  • No wires need to be inserted into the water stream or soil, which could potentially interrupt or change the natural balance of minerals present in the water.
  • It is IP67/NEMA 6 Waterproof to 1 meter/3 feet rated.
  • The device is waterproof and can be fully immersed to 3 feet/1 meter.
  • The unit is manufactured with long life internal electrodes.
  • It is supplied complete with all accessories to perform the measurement.
  • Water resistivity meter comes with thermoformed carrying case.

Why Use a Resistivity Meter for Water Testing?

Resistive meters are popularly called water resistivity monitors or conductivity testers. They are designed to measure the electrical conductivity of water. Here are some pointers that will help you understand why these meters are used for water resistivity tests.

  • Assessment of Water Quality: Electrical conductivity is one of the most crucial parameters to test the quality of water. It indicates the concentration of ions in the water, including minerals, dissolved salts, and other impurities. Low electrical conductivity indicates the need for additional treatment or minerals, while high conductivity values indicate elevated dissolved salts and ions levels. This can impact water's odor, taste, and suitability. 
  • Monitoring Water Purity: Clean and contamination-free water is essential for industrial processes. Different industries, including pharmaceuticals, producing ultrapure water for laboratories and electronics manufacturing, demand pure water. Water resistivity measurement meters help monitor the effectiveness of water purification processes. 
  • TDS and Salinity: Total Dissolved Solids or TDS is a measurement used to analyze water quality in terms of dissolved particles and solids. It quantifies the total concentration of organic and inorganic substances dissolved in water. Conductivity is directly related to TDS. It is possible to estimate TDS levels by measuring conductivity. This information is crucial for determining the suitability of water for specific applications, such as aquaculture, agriculture, or industrial processes, where excessive TDS can be detrimental.
  • Groundwater Exploration: Resistivity meters play a crucial role in groundwater exploration. They help hydrogeologists and geophysicists assess subsurface conditions. With water resistivity tests, expertise can identify potential sources of groundwater contamination, delineate the boundaries of aquifers, gain insights into the geology and stratigraphy of underground formations, and so on.
  • Process Control: Precise monitoring and regulation of water quality is paramount for process control across industries. Resistivity meters make a significant difference here by indicating the concentration of dissolved ions and the purity of process water. These meters allow quick adjustments to water treatment processes, chemical dosage, product formulations, and more by interfacing with control systems and monitoring conductivity. These results help in optimizing efficiency and minimizing product defects.

Factors Affecting the Resistivity of Water

Water resistivity refers to its ability to resist electrical current. However, it is influenced by different factors. Here are some important ones:

  • Concentration of Ion: This is the primary determinant of its resistivity. There are electrically charged particles or ions in water such as chloride (Cl-) and sulfate (SO4²-), sodium (Na+), potassium (K+), calcium (Ca2+), and so on. The higher the ion concentration, the lower is the water resistivity.
  • Dissolved Solids: The presence of dissolved solids in water can impact its resistivity as they may react with the ions. These solids dissociate into water ions, impacting its ability to resist electricity.
  • Temperature: It can significantly impact water resistivity. The resistivity of the water decreases with the increase in the temperature. The reason is that ions move more quickly in warmer water.
  • pH Level: Another factor that can impact the resistivity of water is its pH level. Water with pH 7 is typically more resistive than very acidic or alkaline pH values.
  • Pressure Changes: Pressure changes can also affect water resistivity, although this effect is minor and only significant at very high pressures.
  • Electrolytes: They are substances that dissociate into ions when dissolved in water, significantly influencing water resistivity. Salts, acids, and bases are typical examples of electrolytes.

Applications of Resistivity Meters

The resistivity meter can be used to determine the concentration of suspended solids in water, testing groundwater, checking for contamination from landfill leachate, investigating contamination in lakes, rivers and tidal estuaries. Additionally, it is often used in the fields of geophysics and hydrology for ground water exploration, groundwater level monitoring and detection of groundwater pollution.

Our range of water resistivity meters find immense applications across several industries such as:

  • Construction
  • Metallurgy
  • Mining
  • Manufacturing
  • Civil engineering
  • Water and Wastewater Treatment
  • Boilers and Cooling Towers
  • Aquaculture
  • Paper and Printing
  • Swimming Pools and Spas
  • Plating and Parts Washing
  • Agriculture
  • Process Control
  • Food and Beverage
  • Irrigation Water
  • Hydroponics
  • Laboratories

Overall, the device has been used in many industries and it is an excellent unit for measuring the level of purity of water. The water resistivity meters offered at Cannon Water Technology are well tested on various parameters to deliver quality performance. Buy resistivity meter online from us and avail the most appropriate model from prominent brands at the best prices. If you would like to get more technical details of the models listed, get in touch with our team at the earliest.

Frequently Asked Questions and Answers on Resistivity Meters

Our clients often ask us some common questions regarding resistivity meters. We have answered some of them here.

  • How is Resistivity Measured?

Resistivity is measured using ohm-meters (Ω·m) or ohm-centimeters (Ω·cm), depending on the units used for length. It can also be expressed in other units like ohm-feet or ohm-inches when different length units are used.

  • How Deep Can Resistivity Meters Penetrate inside the Ground?

The penetration depth varies based on the type of resistivity meter used, the configuration of electrodes, and the electrical properties of the measured materials. According to the surveys, resistivity meters can often penetrate up to tens of meters inside the ground.

  • Are There Any Safety Precautions When Using Resistivity Meters?

Yes, safety is paramount when working with any electrical equipment. It is important to follow safety guidelines in the user manual, such as using appropriate tools, proper grounding techniques, and so on to avoid electrical shocks or any other damage.

  • Can Resistivity Meters be Used for Both DC And AC Measurements?

Yes. Most of the resistivity meters are capable of both DC and AC measurements. The choice between DC and AC measurements depends on the application and the material being tested.

  • What Are the Key Components of a Resistivity Meter?

Resistivity meters consist of a current source, electrodes for measuring voltage, electrodes for injecting current into the material, and a display or data collection system.

  • Can Resistivity Meters be Used in Harsh Environmental Conditions?

Most resistivity meters are designed for rugged use and withstand harsh environmental conditions. However, it's essential to check the specifications and capabilities of the meter to ensure it meets the requirements of the intended application. 

  • How Do I Choose the Right Resistivity Meter for My Application?

There are several factors to consider while choosing resistivity meters such as measurement depth, the type of material, required accuracy, and budget. It is always advisable to consult with industry experts for resistivity meter selection.