Flowmeter

A flowmeter is a device for measuring the amount of working substance, liquid, or gas that has passed through a pipeline. Since compressible and incompressible substances have their own measurement specifics, devices in this segment differ in their operating principles. Each category is designed to operate in an environment with certain operational characteristics, has specific parameters, and possesses its own advantages and disadvantages.

Electromagnetic Flowmeters

These devices are based on Faraday's law (electromagnetic induction). An electromotive force is generated under the influence of water or another conductive liquid passing through a magnetic field. The liquid flows between the poles of a magnet, creating an EMF, and the device measures the voltage between two electrodes, thereby measuring the flow volume. This device operates with minimal errors provided it transports purified liquids and does not impede the flow.

Advantages of Electromagnetic Flowmeters

There are no moving or stationary parts in the cross-section, which helps maintain the liquid transport speed.
Measurements can be made over a wide dynamic range.

Disadvantages

If the liquid contains magnetic and conductive sediments or contaminants, the device will operate with distortions.

Ultrasonic Flowmeters

This type of flowmeter is equipped with ultrasonic signal transmitters. The speed of the signal traveling from the transmitter to the receiver changes each time the liquid moves. If the ultrasonic signal travels in the direction of the flow, the time decreases; if against it, the time increases. The volumetric flow of the liquid is calculated based on the difference in signal travel time downstream and upstream. Typically, these devices come with an analog output and a microprocessor control unit, and all displayed data is shown on an LED display.

Advantages of Ultrasonic Flowmeters

Resistance to vibrations and shocks.
Durable and stable housing.
Suitable for the oil refining industry and cooling systems.
Measure the flow of water and liquids with physical properties similar to water.
Operate within a medium dynamic measurement range.
Can be installed on pipelines with large diameters.

Disadvantages

Increased sensitivity to vibrations.
Sensitivity to sediments that absorb or reflect ultrasound.
Sensitivity to flow misalignment.

Tachometric Flowmeters

In tachometric flowmeters, the main measuring element is a impeller or turbine (arranged perpendicular or parallel to the flow, respectively). The rotation speed and the number of revolutions made in the flow are measured.

Advantages

Suitable for measuring the flow of liquid, steam, and gas.
Simple and inexpensive models.
Easy to install on small-diameter pipelines and often used in household settings.
Operate without a power source; no electrical connection required.

Disadvantages

For large-diameter pipelines (i.e., in industrial metering), tachometric flowmeters are too expensive due to high metal consumption and are also too bulky.
Create hydraulic resistance to the flow and, in the case of large diameters, can cause "blockage" or fail due to mechanical breakdowns.
Low reliability for industrial measurements, small dynamic range.
Insufficient measurement accuracy: results are affected by impurities and foreign objects in the flow.
The service life is not high enough: suitable for household conditions, but not for industrial use.

Coriolis Flow Meters

The operating principle is based on the Coriolis effect: U-shaped tubes are subjected to oscillations during flow, and the vibrational oscillations, in turn, cause the substance to twist. The phase shift magnitude depends on the mass flow rate of the liquid or steam. The flow is measured considering the formed twisting angle. Most often, such flow meters are used for liquid media, including paints, varnishes, and liquid polymers.

Advantages

Mass flow is measured directly.
Deposits or contaminants dissolved in the liquid do not affect measurement results.
There are no obstacles in the internal cross-section; the system operates stably.
Suitable for measuring all types of liquids, regardless of their electrical conductivity.

Disadvantages

High cost, complex technological components.
Requires high-precision installation.
Measurement accuracy may vary under strong vibrations.

Vortex Flow Meters

These devices measure the frequency of oscillations that occur in a gas or liquid flow when bypassing obstacles. The flow around the obstacles leads to vortex formation (hence the name of this type of device), and the magnitude of vortex changes allows calculating the flow rate.

Advantages

Suitable for measuring the flow of gases, technical air.
No moving parts in the design.

Disadvantages

There are mechanical obstacles in the cross-section that hinder the movement of the medium.
Measurement accuracy significantly decreases if the bluff body is contaminated.
The device is sensitive to temperature changes.
Vibrations affect the results.
Measurements are possible within a small dynamic range.

Vortex flow meters measure the frequency of oscillations that arise in a liquid or gas flow when they bypass obstacles. When flowing around obstacles, vortices form, from which the devices get their name.

Differential Pressure Flow Meters

The operating principle of these devices is based on measuring the pressure drop that occurs when a liquid or gas flow passes through a narrowing device (orifice plate, nozzle). At this point, the flow velocity changes, and the pressure increases. Measurements at the obstacle point are made using a differential pressure sensor.

Advantages

There are no moving parts in the device.

Disadvantages

Measurements are possible within a small dynamic range.
Any deposits on the narrowing device lead to significant errors.
Mechanical obstacles in the cross-section reduce the reliability of the design.

These six options are considered the main types of flow meters for measuring volumes of liquids and gaseous media, air, and water.

Izmerkon company offers a wide selection of industrial air and compressed gas flow meters, including those with digital interfaces. You can choose a suitable model based on the description or by consulting with our managers. Our company from Saint Petersburg provides shipping of measuring instruments throughout Russia.