Ultrasonic Flow Meters

20+ Years Manufacturing Experience

Why do ultrasonic water meters represent the current mainstream trend？

Key Highlights of the WM9100 Series Ultrasonic Water Meter

01. Long‑Life Battery

With 10 years shelf life battery. No moving parts, excellent long-term stability and reliability.

02. Material

With stainless steel (SUS304) body.

03. Multiple Output Options Available

RS485, M-bus, LoRaWAN,NB-IoT and so on.

04. Protection Class

IP68 design, longtime under water working.

05. Prepaid Function

An integrated valve for prepaid function is available as an option.

06. Selectable Turndown Ratio

With the turn-down ratio as R250, R400 for optional.

1.WM9100 Series Ultrasonic Water Meter — Product Portfolio Summary

The WM9100 series covers residential and bulk‑size ultrasonic water meters, covering nominal diameters from DN15 up to DN600. All models adopt stainless‑steel SUS304 body (SS316L optional), no‑moving‑part ultrasonic measurement, comply with ISO4064 Class 2 accuracy and drinking‑water sanitary standards, with IP68 protection for long‑term underwater operation.

A. Residential ultrasonic water meters (DN15‑DN25, thread connection)

  • WM9100‑ED: Direct‑reading type, non‑replaceable battery with 10‑year shelf‑life.
  • WM9100‑EV: Prepaid valve‑integrated version based on WM9100‑ED.
  • WM9100‑BD: Direct‑reading type, replaceable battery, 10‑year service life.
  • WM9100‑BV: Prepaid valve‑integrated version based on WM9100‑BD.

Turndown ratio: standard R250, optional R400. Communication options: RS485, M‑Bus, LoRaWAN, NB‑IoT.

B. Bulk‑size ultrasonic water meters

  1. DN32‑DN40: Thread‑type bulk meter. Turndown ratio: standard R250, optional R500. Outputs: RS485, Pulse, LoRaWAN, NB‑IoT, GPRS.
  2. DN50‑DN300: Flange‑connected bulk meter. Available in full‑bore double‑channel (A2) and 20% reduced‑bore (B); DN50‑DN150 max working pressure 1.6 MPa; DN200‑DN300 max working pressure 1.0 MPa. Turndown ratio: standard R500, optional R1000. Valve control function is optional.
  3. DN350‑DN600: Flange‑connected extra‑large‑size meter with four‑channel ultrasonic sensor. Turndown ratio: standard R250, optional R400 / R500. Max working pressure 1.0 MPa.

All bulk‑size meters are equipped with built‑in 10‑year data logger, multi‑alarm indication, and rich communication interfaces.

2. What is the working principle of the ultrasonic water meter?

Ultrasonic Tansit-time method

The WM9100‑series ultrasonic water meter adopts transit‑time difference measurement technology for flow calculation. Paired ultrasonic transducers are installed inside the measuring tube. They alternately transmit and receive ultrasonic pulses along and against the direction of water flow.

Ultrasonic signals travel faster when moving downstream with water flow and slower when propagating upstream against the flow. The high‑precision electronic unit captures this tiny propagation‑time difference. Combined with the pipe geometric parameters, the microprocessor computes water flow velocity, instantaneous flow rate and accumulated total water volume.

There are no moving mechanical parts within the measuring channel. All measurement is completed by pure electronic signal processing. The measured data can be displayed on local LCD, stored in the built‑in data logger, and uploaded remotely via RS485, M‑Bus, LoRaWAN or NB‑IoT communication interfaces.

3. What Are the Key Features of the WM9100 Series Ultrasonic Water Meter?

No moving mechanical parts Adopts ultrasonic transit‑time difference measuring principle without any moving parts, minimizing wear and delivering outstanding long‑term stability and reliability.
Wide turndown ratio options Multiple turndown ratios are available from R250 up to R1000, ensuring accurate measurement for both tiny low flow and large‑volume flow conditions.
Bidirectional flow measurement Supports both forward and reverse flow measurement, capable of detecting backflow and abnormal water‑use status.
Long‑life battery power supply Two battery solutions for selection: non‑replaceable battery with 10‑year shelf‑life or field‑replaceable battery with 10‑year service life, low power consumption ≤0.3 mW.
IP68 high‑grade waterproof performance IP68 protection rating, supports long‑term underwater and buried installation, adapts to harsh wet manhole environments.
Multiple remote communication interfaces Rich communication options including RS485, M‑Bus, Pulse, LoRaWAN, NB‑IoT and GPRS, convenient for smart water‑system remote data reading and management.
Multi‑active alarm & indication function Built‑in active alarms for leakage, water theft, backflow, meter tampering, abnormal flow and low battery status; alarms can be shown on local LCD and read remotely.
Built‑in historical data logger On‑board data logger stores historical consumption data by year /month/day, data storage period up to 10 years; recorded data will not be lost after power‑off.
Flexible hardware configuration options SUS304 standard body with optional SS316L material; prepaid valve, pressure measurement function are optional; covers DN15‑DN600 full size range (thread & flange connection).
Complies with international measurement standard Measurement accuracy meets ISO4064 Class 2, suitable for potable drinking‑water metering for residential and bulk‑size pipeline projects.

4. What working environmental conditions can the WM9100 series ultrasonic water meter adapt to?

For ambient environment, its operating ambient temperature ranges from ‑40 ℃ to +70 ℃, relative humidity up to 100%RH. The protection class reaches IP68, so it can work for a long‑time under water, suitable for buried installation in water wells and wet manhole environments. Max working pressure is 1.6 MPa for DN15‑DN150; for DN200‑DN300 large‑size meters, the maximum working pressure reduces to 1.0 MPa. Temperature class is T30 as standard, T50 is optional for residential models. In terms of environmental compatibility, it meets climatic & mechanical environment Class O and E2 electromagnetic compatibility requirements, which enables stable operation under complex outdoor interference conditions. Please note that the meter complies with drinking‑water sanitary standards for potable water measurement, it is intended for clean drinking‑water, not for heavily polluted sewage.

 

5. What are the advantages of ultrasonic water meters compared with mechanical water meters?

  1. No moving mechanical parts: Without impellers or gears. No wear, no jamming risk from water impurities, long‑term consistent metering accuracy. Mechanical meters suffer accuracy decline as internal parts wear over service time.
  2. Superior low‑flow performance & wide turndown ratio: Ultrasonic meters can accurately measure tiny leakage flow with high R‑value (R250‑R1000). Most mechanical meters have limited turndown ratio and fail to record small drip flow.
  3. Native digital & smart functions: Built‑in digital output, historical‑data logger, multi‑alarm functions for leak, tamper and backflow. Mechanical meters usually need extra add‑on modules to realize remote reading, without built‑in alarm and data storage capability.
  4. Lower maintenance work: Less on‑site repair and replacement work thanks to wear‑free structure. Mechanical meters require regular inspection and replacement due to wearing parts.
  5. Better environmental adaptability: IP68 underwater‑proof design, suitable for buried manhole installation. Ultrasonic meters keep stable performance under complicated outdoor conditions.

6. Why are ultrasonic water meters becoming the prevailing trend nowadays?

Ultrasonic water meters match the development direction of smart water‑supply systems. Firstly, they adopt no‑moving‑part solid‑state measurement technology, avoiding accuracy drift caused by mechanical wear, delivering long‑term stable metering performance and lowering later‑stage maintenance costs. Secondly, they support multiple digital communication interfaces for remote meter reading, leakage monitoring and abnormal alarm, which is critical for smart water management. Thirdly, they feature an extra‑wide turndown ratio, capable of capturing tiny low‑flow leakage that traditional mechanical meters often miss, reducing water‑supply revenue loss. Besides, they have long battery life, high IP68 waterproof grade and wide‑range product portfolio covering residential to large‑diameter pipeline projects. For water utilities, ultrasonic solutions bring better whole‑life‑cycle economic benefits, so they are gradually replacing conventional mechanical meters.

 

7. The Application of WM9100 Series Ultrasonic Water Meter.

The WM9100‑series ultrasonic water meters cover a complete size range from DN15 to DN600 to satisfy diverse metering requirements for smart water supply projects. Thread‑type DN15‑DN25 models are mainly deployed for residential household metering, apartment buildings and prepaid water‑fee management. DN32‑DN40 thread meters apply to small‑scale commercial premises, community branch pipelines and building total‑water‑consumption monitoring. Flange‑connected DN50‑DN300 large‑diameter meters are widely adopted in DMA district metering areas, municipal distribution pipe networks, industrial water‑supply pipelines, hotels, hospitals and shopping malls for bulk‑volume water measurement. Extra‑large‑size DN350‑DN600 meters serve for municipal trunk transmission mains and major water‑supply nodes. Thanks to IP68 submersible capability, rich communication options and multi‑alarm functions, the whole series adapts to underground manhole, buried installation and various harsh field environments, supporting remote reading, leakage detection and non‑revenue‑water reduction for water utilities.

 

FAQ About the WM9100 Series Water Meter

Q1. What factors will affect the measuring accuracy of WM9100 ultrasonic water meter?

Although the WM9100 series has no moving parts and delivers stable metering performance, several field factors may influence its measuring accuracy. First of all, excessive air bubbles inside the pipeline are the primary interference source. Large amounts of bubbles will reflect ultrasonic pulses and weaken signal strength, leading to inaccurate or unstable readings. Secondly, dirty pipe walls or heavy sediment buildup on ultrasonic transducers will attenuate ultrasonic signals. It is recommended to keep the medium as clean drinking water and avoid sewage with high sediment content. Thirdly, installation conditions play a vital role. The meter requires sufficient upstream and downstream straight pipe sections. If elbows, valves or reducers are mounted too close to the meter inlet and outlet, distorted flow profiles will cause measurement deviation. Besides, extreme operating temperature beyond ‑40℃~+70℃ and strong external electromagnetic interference may also bring minor impact. When installed following official installation instructions and used with clean bubble‑free tap water, the meter can consistently maintain ISO4064 Class 2 accuracy.

Q2. What is the difference between replaceable‑battery model WM9100‑BD and non‑replaceable‑battery WM9100‑ED? Which one should I choose for my project?

The core difference lies in battery structure and service‑life definition. WM9100‑ED / EV adopt non‑replaceable built‑in lithium battery with 10‑year shelf life. Shelf‑life means the maximum storage duration before installation. Once installed and put into operation, the actual working life depends on communication upload frequency and alarm trigger frequency. When the battery is exhausted, users cannot open the meter to replace the battery; the whole meter needs to be replaced. In contrast, WM9100‑BD / BV are equipped with replaceable batteries with 10‑year operating life under typical working conditions (power consumption ≤0.3 mW). When power runs low, technicians can open the battery compartment and replace the battery on‑site without removing the whole meter from pipeline. Except for battery design, both series share identical hardware: SUS304 body, turndown ratio options, communication interfaces, IP68 protection, alarm functions and data‑logging capacity. For new large‑scale residential projects with low later‑stage maintenance manpower, WM9100‑ED is cost‑effective. If your project is hard‑to‑access underground manholes and you want to avoid full‑meter replacement after battery depletion, WM9100‑BD with replaceable battery will be the better option.

Q3. How does the built‑in data logger work on WM9100 series, and will historical data get lost under power‑off or low‑battery condition?

All WM9100 ultrasonic water meters are fitted with an independent built‑in data logger. It automatically archives water consumption data on yearly, monthly and daily basis, supporting up to 10‑year historical records storage. The flow sampling frequency of the meter is 1‑4 times per second, while it does not store every second‑level raw flow data. Instead, it stores aggregated periodic cumulative consumption data. All stored historical records are saved into non‑volatile memory chip. Even when battery voltage drops to low‑battery alarm threshold or the battery is completely exhausted, the saved historical data will not be erased or lost. Users can retrieve historical data in two ways: reading records locally from the LCD display screen on site, or remotely fetching year‑month‑day historical archives via RS485, M‑Bus, LoRaWAN or NB‑IoT communication interfaces. Please note that the data logger cannot store continuous second‑by‑second flow curve; only periodic cumulative consumption and event alarm records are available. If you need high‑frequency real‑time flow curve recording, additional external data acquisition device shall be equipped.

Q4. What are the differences between full‑bore type and reduced‑bore type for DN50‑DN300 WM9100 large‑diameter water meters, and how to select?

For DN50‑DN300 flange ultrasonic water meters, there are two mechanical structures: A2 full‑bore type and B 20% reduced‑bore type. The A2 full‑bore model keeps the same inner diameter as nominal pipe size. It creates minimum pressure loss, suitable for pipelines where pressure drop must be strictly controlled. Its flow profile sensitivity class is U5/D3. The B type is 20% reduced‑bore structure, the inner measuring section is slightly narrowed. This structural design improves low‑flow measuring performance and achieves higher turndown ratio up to R1000, yet it will generate relatively higher pressure loss compared with full‑bore version. Its flow profile sensitivity class is U3/D0. If your pipeline runs mostly under large flow condition and pressure loss is your top concern, choose A2 full‑bore type with standard R500 turndown ratio. If your site has frequent small‑flow conditions and you hope to capture tiny leakage flow while pressure loss allowance is acceptable, B type 20% reduced‑bore with optional R1000 will be more suitable. Both versions comply with ISO4064 Class 2 accuracy requirement for legal metering.

Q5. What communication options does WM9100 series support, and what should be noticed when selecting communication modes for projects?

WM9100 series provides rich communication selections. Residential DN15‑DN25 supports RS485, M‑Bus, LoRaWAN and NB‑IoT. DN32‑DN300 adds Pulse and GPRS output on that basis. Extra‑large DN350‑DN600 supports RS485, Pulse, LoRaWAN and NB‑IoT. Wired interfaces include RS485 Modbus and M‑Bus, which are suitable for short‑distance centralized wiring scenarios. They feature stable signal and low operating cost, but require on‑site cable laying work. Wireless options contain LoRaWAN, NB‑IoT and GPRS. LoRaWAN needs matched local LoRa gateway deployment; NB‑IoT and GPRS rely on cellular operator network, no gateway required on‑site, but SIM card annual data service fee shall be considered. Pulse output is dry‑contact pulse signal for connecting third‑party data collector. When choosing communication modes, you need to evaluate site conditions: whether cables can be laid, wireless signal coverage on‑site, project budget, and operating‑fee budget for SIM cards. Please also note that higher data upload frequency will shorten the overall battery service life of the battery‑powered water meter. If you set very frequent report intervals, actual battery running time will be shorter than theoretical value.

1
Arina Hu | Sales Engineer

Graduating with a Bachelor’s in Business English, as a sales engineer of Lanry Instruments more than 5 years.

Having participated in multiple overseas exhibitions,possess in-depth product knowledge of our complete instrument lineup

and strong capabilities for international client engagement.Should you have any project demands for instruments, pls feel free to contact me.

Post time: Sep-02-2026

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