A flow meter is a device that measures the volume of working fluid that passes through a pipe over a period of time. There are several models on the market today with different operating principles, each with its own set of performance characteristics. One of the most popular options is the electromagnetic and ultrasonic options. These devices are characterized by high measurement accuracy, ease of use, reliable and stable operation. However, they have their own differences, advantages and disadvantages. This will be discussed below.
Characteristics of Electromagnetic Equipment
The operation of this flowmeter is based on the law of electromagnetic induction. Under the influence of water or other conductive working medium passing through a magnetic field, an electric current is formed. That is, the working medium passes between the magnetic poles and generates an electromotive force. A voltage appears between the electrodes, which is fixed by the device. From the data obtained, the volume of the working medium passing through the pipe is calculated.
The advantages of electromagnetic flowmeters include:
There are no fixed elements and moving mechanisms inside the measuring block. Therefore, there is no obstacle to the movement of the working medium, thus maintaining the specified transport speed;
Large dynamic measurement range;
Minimum error in compliance with operating rules.
However, the correct operation of the device depends on the following factors:
The quality of the work environment. If it contains third-party impurities, conductive or magnetic inclusions, significant distortion of the measurement results will be observed;
Install. Measurement errors cannot be avoided if equipment is installed against technology (improper installation, connection, calibration). Installation work may only be carried out by professional service representatives;
Are there any electrical appliances nearby. External electromagnetic fields can adversely affect the flowmeter, so it must be kept away from any electrical equipment;
The presence of a constant power supply. Magnetic flowmeters only function when connected to an external power source. Therefore, it is recommended to install them in facilities with stable power supply.
Disadvantages of this device include the possibility of use only with conductive working fluids, such as water. Electromagnetic models have been used in general house accounting in energy consumption and other fields. However, due to the poor quality of the conductive working environment in many facilities, they are used less frequently.
Features of Ultrasonic Flow Meters
These flow meters are equipped with ultrasonic signal transmitters. When the working medium is flowing, the velocity of the measurement signal from the generating device to the receiving device is measured. The ultrasonic transmitter emits a signal, which is fixed by the receiver after a certain time interval. The transit time decreases if the signal motion vector is consistent with the flow motion, and increases if the vector is opposite. After calculating the travel time difference of the signal along the flow and against the flow, the device calculates the volume flow of the working medium. Most models of ultrasonic flow meters are equipped with an electronic computing mechanism, a control unit, an output for remote data transmission and an informational LCD.
Additional benefits of ultrasonic flow meters include:
Flow measurement of any type of liquid;
High resistance to mechanical stress;
Stability, reliability and long service life;
Can be installed on pipes with large cross-sectional areas.
This type of flow meter is designed to measure the average dynamic range. Their minor disadvantages include susceptibility to vibrations, susceptibility to substances that absorb or reflect ultrasonic waves, and susceptibility to water flow deformation. All of these problems can be solved by properly installing the device.
An example of an ultrasonic flowmeter under the Pulsar trademark
LLC NPP "TEPLOVODOKHRAN" manufactures ultrasonic flowmeters for various applications including:
Ultrasonic Heat Meters for Houses and Apartments - Devices with visual readout, and pulsed or digital output for remote data transmission. Released in a modified version of Du 15 — Du 20 (depending on the diameter of the conditional pass);
Common household ultrasonic heat meters with digital or radio output. Released as a modified Du 15 — Du 50;
Ultrasonic Water Meter - with visual readout, digital, pulse or radio output. Issue conditional pipes of different diameters - from 15 to 200 mm.
Devices equipped with outputs for remote data transmission can be integrated into a single automated energy consumption accounting and control system.
Pulsar branded models may operate in systems where the work environment contains third party impurities. They have become the best substitute for electromagnetic instruments in systems that use other types of non-conductive liquids instead of water as the working medium. The devices are equipped with their own power source - a high-quality, high-energy-consuming battery, so they can work autonomously and not depend on the facility's power source.
Which flowmeter to choose - the consumer decides himself, taking into account the characteristics of the object, the type of working environment, the nominal diameter of the pipe, the task of organizing the energy accounting, the financial capacity.
