What Is An Ultrasonic Water Meter?
Ultrasonic water meters use ultrasonic waves to measure water consumption. Because the transmission speed of ultrasonic waves can be affected by the speed of water flow. The water flow speed is calculated to determine water consumption by recording the ultrasonic transmission time. Ultrasonic water meters have high measurement accuracy and a large measuring range, and are the most comprehensive and practical water meters.
What Are Ultrasonic Waves?
We must first define ultrasonic waves to grasp how ultrasonic water meters work.
Ultrasonic waves are defined as mechanical sound waves with frequencies above 20 kHz, beyond the range of human hearing.
Ultrasonic waves propagate through water and other media, with their speed influenced by both the medium’s properties and its flow velocity.
Why Use Ultrasound? Can’t Other Types Of Waves Be Used In Water Meter Measurement?
Ultrasonic waves are suitable for water measurement, resulting from comprehensive consideration of the physical properties, measurement principles, and engineering applicability of ultrasound.
What Are The Characteristics Of Ultrasound?
- Good propagation in liquids: Ultrasonic waves can propagate in liquid media with little attenuation.
- Propagation speed is affected by the flow velocity of the medium (Propagation Speed Affected by Medium Velocity): Ultrasonic waves accelerate when propagating downstream (sound speed + water flow velocity component), and slow down when propagating upstream (sound speed – water flow velocity component)
- Accurate directionality: Ultrasonic waves are high frequency and short wavelength, which makes ultrasonic waves have good directionality, concentrated energy, and are easy to propagate in a specific direction.
Ultrasonic waves can accurately transmit and receive signals. From the beginning of transmission, ultrasonic signals must experience at least 2 reflections in the water pipe before they are emitted to the receiver. The accurate directionality of ultrasonic waves meets this requirement.
Why Can’t Other Waves Be Used For Water Consumption Measurement?
Light waves: require transparent pipes and are severely scattered in water, making it difficult to receive signals.
Ordinary sound waves: low frequency (20Hz~20kHz), easily interfered by environmental noise, affecting measurement results.
Operating Principle Of Ultrasonic Water Meters:
Ultrasonic water meter currently has two main metering methods: Transit Time Method そして Doppler Effect Method.
The transit time method is the most commonly used ultrasonic water meter measurement method, and the Doppler effect method is suitable for the industrial field with poor water quality.
How Is The Ultrasonic Wave Produced In The Ultrasonic Water Meter?
By applying an alternating electrical signal above 20 kHz to the transducer/sensor, the ultrasonic transducer can generate tiny high-frequency mechanical vibrations, which are converted into ultrasonic waves.
What Are The Advantages Of Ultrasonic Water Meters?
Compared with mechanical water meters, ultrasonic water meters have 11 main advantages:
1. High Accuracy:
Combined with electronic technology (high frequency clocks, precision timing circuits), tiny time differences can be measured very accurately, with accuracy down to the nanosecond (ns) level, thus accurately calculating velocity and flow rate.
The sensitivity of ultrasonic water meters is much higher than that of mechanical water meters, especially in measuring small flows (even drips). The ultrasonic water meter can measure a starting flow rate of 1 liter/hour, while the mechanical meter’s starting flow can only be 6-7 liters. This capability significantly reduces water loss caused by unmeasured low flows.
2. Long Lifespan:
With no mechanical components, ultrasonic water meters avoid wear-related lifespan reduction. Because of wear and tear, the service life of mechanical water meters in different countries is set at about 6-8 years.
3. Stable Long-Term Accuracy:
Mechanical water meters degrade as impellers and gears wear, whereas ultrasonic models maintain precision with no moving parts to deteriorate.
4. Strong Resistance to Impurities:
The pipeline of the ultrasonic water meter is unobstructed, and it is not easy to be blocked or stuck by impurities such as sand and rust in the water, and the environment with poor water quality can also be measured.
5. Low Pressure Loss:
The structure of the ultrasonic water meter pipe is simple, and the resistance of the water flow through the measuring pipe section is small, unlike the pressure loss caused by the rotation of the impeller caused by the mechanical water meter.
6. Wide Rangeability (R Ratio):
Ultrasonic water meters with DN15 caliber, for example, can be effectively measured from 0.001 m³/h/ h-5 m³/h. The mechanical water meter can only measure the flow in the range of 0.004m³/h – 3m³/h.
7. Data recording and analysis:
It can generally store up to 2 years of historical consumption data, instantaneous flow, water temperature, and other information, and support advanced functions such as water leakage detection and water consumption pattern analysis. Ultrasonic water meters can also be customized according to customer requirements to store longer historical data.
8. Fault diagnosis and alarm:
Can detect reverse flow, air pipe, battery low voltage, sensor failure, water temperature, water pressure, data, and other abnormal states and issue alarms.
9. Bidirectional Measurement Capability:
By comparing the transit time of upstream and downstream ultrasonic signals, the direction of water flow can be judged, and the forward and reverse flow can be measured respectively.
10. Installation Flexibility:
Mechanical water meters can usually only be installed horizontally or vertically. The ultrasonic water meter can be installed in the horizontal/vertical/inclined direction without affecting the measurement accuracy. However, it is still necessary to follow the manufacturer’s installation guidelines to ensure optimal performance.
11. Strong Immunity to Magnetic Interference:
Some mechanical water meters are magnets with wheel gear rotation, which can receive external magnetic field interference. The working principle of the ultrasonic water meter is different, and it is not interfered with by the external magnetic field, and the use of strong magnets to interfere with the mechanical water meter count is avoided.
What Are The Differences Between Ultrasonic Water Meters And Mechanical Water Meters?
There are many differences between ultrasonic water meters and mechanical water meters, and the following are the most important 3 differences:
- Different technologies: Ultrasonic water meters are essentially different in measuring technology, and the measurement is more accurate.
- Different structure: there are no impellers, gears, and other mechanical rotating parts in the internal structure of the ultrasonic water meter.
- The accuracy is different: the measurement accuracy of the ultrasonic water meter can reach R800, while the mechanical multi-water meter can only reach R160 ( R=Q₃/Q₁)
The Main Difference Between Ultrasonic Water Meter, Mechanical Water Meter, Electromagnetic Flow Meters
| 特徴 | 機械式水道メーター | 超音波式水道メーター | Electromagnetic Water Meter |
|---|---|---|---|
| Measurement Principle | Physical displacement | Acoustic principle | Electromagnetic induction |
| Moving Parts | Yes | No | No |
| 正確さ | 中くらい | 高い | 高い |
| Turndown Ratio (R) | 低い | Wide | Wide |
| 圧力損失 | Significant | Minimal | Nearly zero |
| Water Quality Requirements | Sensitive to impurities | Sensitive to bubbles/particles | Requires minimum conductivity |
| Starting Flow | Relatively high | Extremely low | 低い |
| Power Requirement | Not needed | Required | Required |
| Smart/Communication | Basic models lack | Ideal for smart systems | Ideal for smart systems |
| Installation | May have orientation limits | Flexible | Flexible |
| Durability/Lifespan | Relatively short | Long | Long |
| Interference Resistance | Vulnerable to magnetic fields | Resistant to magnetic fields | Resistant to external fields |
| Cost | 低い | Medium to high | 高い |
| Typical Applications | Residential/small commercial | Residential/commercial/industrial/DMA | Industrial/water plants/trade settlement |
Choose The Best Ultrasonic Water Meter Supplier
BMAG designs and manufactures ultrasonic water meters that undergo extensive simulation testing. We conduct rigorous experiments under numerous conditions—including variations in water quality, temperature, air bubbles, low flow rates, and installation angles—and perform data optimization. This ensures that BMAG ultrasonic water meters deliver accurate measurements in diverse environments.
