Dual channel ultrasonic flowmeter is an instrument used to measure liquid flow rate. It utilizes the characteristics of ultrasonic propagation to measure flow and improves measurement accuracy through a dual channel design based on the Doppler effect. When ultrasonic waves pass through a liquid flowing medium, a frequency change occurs due to the fact that the speed of liquid flow is different from the speed of ultrasonic waves in a stationary medium. This frequency change is called Doppler shift. The flow velocity of a liquid can be calculated based on the magnitude of the Doppler shift.

When ultrasonic waves pass through a liquid flowing medium, the radial direction of ultrasonic waves will be affected by Doppler frequency shift, and the frequency will change. Ultrasonic waves in the diameter direction are not affected by Doppler frequency shift, and their frequency remains unchanged. By measuring the frequency difference between radial ultrasonic waves and diameter ultrasonic waves, the liquid flow velocity can be calculated.

The specific calculation process is as follows: By using the ultrasonic signals received by two receivers, frequency signals in the radial and radial directions can be obtained separately. Then, the signal processor will process these frequency signals and calculate the frequency difference. By calibration and other methods, the frequency difference is converted into actual flow velocity values and displayed on the monitor.

Multi channel ultrasonic flowmeter is a device that measures fluid flow velocity by detecting the effect of fluid flow on ultrasonic beams. According to the detection method of signals, it can be divided into propagation velocity difference method, Doppler method, beam offset method, noise method, and correlation method. The Doppler method utilizes the principle of acoustic Doppler to determine fluid flow rate by measuring the ultrasonic Doppler frequency shift scattered by scatterers in non-uniform fluids. It is suitable for measuring fluid flow rates containing suspended particles, bubbles, and other substances. The beam offset method uses the deviation of the propagation direction of the ultrasonic beam in the fluid as the fluid velocity changes to reflect the fluid velocity. At low flow velocities, the sensitivity is low and the applicability is limited. The widely used measurement principle currently is the “time difference method”. Combining multi pulse technology, digital information processing technology, and signal processing circuits to display measurement data in real-time. The “time difference method” is to generate ultrasonic signals by sending sensors and emit them into the air flow. The signals pass through the pipe wall and fluid to the receiving sensor, and at the same time, the receiving sensor emits the same ultrasonic signals. The signals pass through the pipe wall and fluid to the sending sensor. At this point, due to the presence of flow velocity, the time difference can be used to calculate the flow velocity and subsequently the flow rate.

Operation and usage steps of dual channel ultrasonic flowmeter:

1. Preparation: Place it in a suitable location and ensure there is enough space for installation and operation.
2. Install sensors: Install sensors as needed and ensure that they are securely connected to the flow meter.
3. Connect the power supply: Connect the flowmeter to the power supply and ensure that the power supply is stable.
4. Turn on the instrument: Press the power switch to turn on the instrument.
5. Parameter setting: Set parameters as needed, such as units, temperature correction, etc.
6. Measurement: Pass the fluid through a sensor, observe the display screen, and record the data.

Advantages of dual channel ultrasonic flowmeter

1. Simultaneously supporting both mono and stereo channels, and when one channel is abnormal or disconnected, it can automatically switch to mono operation based on signal quality;
2. Adopting the latest 32-bit Cortex-M4 core CPU as the processor core, using 64 bit floating-point operations, the calculation does not lose accuracy;
3. Using high-speed ADC to collect ultrasonic signals, with ultrasonic waveform restoration and reconstruction technology; Using precision time measurement chips, the ultrasonic flight time accuracy can reach 22 picoseconds;
4. Single board and full surface mount technology are all soldered using SMT machines, greatly reducing issues such as virtual soldering, solder leakage, and short circuits on circuit boards.
5. Thermal function: Optional PT100 external clip on platinum resistor can achieve thermal measurement.

Technical parameters

medium	The vast majority of single-phase liquids, less than 5% particles or bubbles
Pipe material	Stainless steel, PVC, carbon steel
Ambient temperature	-40℃～+60℃
Fluid temperature	-20℃～+120℃
Explosion-proof class	Flameproof Exd II BT4
Velocity range	Nominal accuracy flow rate range 0.1 ~ 12.5m/s
Measurement accuracy	±0.5%
sensitivity	0.001m/s
Measurement repeatability	±0.2%
Class of protection	IP65
Power source	12V～24VDC，0.5A
Electrical interface	Waterproof head 2M201.5
LCD display	128*64 lattice liquid crystal
Serial communication	RS485,MODBUS RTU protocol

Maintenance methods for dual channel ultrasonic flowmeter:

1. Regular calibration: Regularly calibrate to ensure the accuracy of measurement results.
2. Clean the sensor: Regularly clean the impurities on the surface of the sensor to prevent them from affecting the measurement results.
3. Dustproof and moisture-proof: Keep the sensor dry to prevent water ingress and dust accumulation, to ensure normal operation.
4. Regular maintenance: Regularly check whether each component is worn or loose, and repair or replace it in a timely manner.
5. Pay attention to protection: prevent impact, vibration, or severe shaking to avoid affecting measurement results and instrument life.
6. Pay attention to the usage environment: avoid exposure to high temperature, low temperature, high humidity or corrosive gas environment to prevent damage.

Application fields of dual channel ultrasonic flowmeter

Application: Medical/Health, Environmental Protection/Water Industry, Food/Beverage, Chemical Testing, Petroleum/Chemical Industry.