Spire Metering Technology, LLC.

- Model wPrime Series 280W-CI4 - Ultrasonic Water Meter



Spire Metering offers the latest in Commercial/Industrial ultrasonic metering technology for reliable flow measurement. The rugged 280W-CI water meter will provide sustained flow accuracy for the life of the meter while providing connectivity to smart AMR/AMI solutions.

  • Any application that requires high accuracy across all flow rates for revenue billing
  • Municipal, commercial, and distribution applications including reclaim and irrigation water requirements
  • Commercial buildings: malls, campus, hospitals, industrial parks, airports, facilities
  • Industrial water: steel, heavy manufacturing plants, power plants, food & beverage
  • Leak and tamper detection, DMA (District Metered Area) leakage detection system
  • AMR/AMI projects which require flow accuracy with an economical solution

  • Fully encapsulated in a heavy-duty enclosure with IP68 rating
  • No moving parts; dependable ultrasonic performance without maintenance
  • Excellent performance at all flow rates; accuracy does not degrade over the life of the meter
  • NSF-61G Approved
  • Not affected by water impurity. Withstands the challenges in harsh environments, such as the Middle East and Africa
  • Low pressure drop. Saves significant pumping cost
  • Exceed ISO4064 Class D and AWWA C715
  • 10 Year battery life
  • Bi-directional flow; no strainer required
  • Does not measure entrained air in pipe
  • Unaffected by magnetic interference
  • DN50 (2”) to DN600 (24”) sizes
  • Tamper-proof design
  • AMR/AMI ready with Encoder pulse, 4-20mA, M-Bus, Modbus, BACnet, long range RF or GPRS wireless
  • Data Logger with 700 daily totals and 24 monthly totals
  • Built-in temperature sensor for wide range temperature compensation


A member of the wPrimeTM Series, the 280W-CI Ultrasonic Water Meter is specially designed for commercial and industrial water metering applications where the environment is challenging and traditional mechanical water meters fail.

280W-CI is carefully engineered to offer robust performance in harsh environments. The flow sensor utilizes a crystal to generate an ultrasonic signal. There are no moving parts to wear out over time, as in traditional mechanical meters. The electronics, transducers and cables are all encapsulated in a heavy-duty metal enclosure which is IP 68 rated. It is suitable for both outdoor and indoor applications and anywhere the meter may be submersible.

The 280W-CI offers the most advanced water flow measurement by using state-of-the-art multi-path ultrasonic technology. It employs 2 pairs or 4 pairs of ultrasonic transducers to interrogate the flow from different positions, so that flow profile distortion has minimal impact on the measurement results. This is a significant improvement compared to singlepath ultrasonic flow meters, because it is very common in real applications that there is not enough straight-pipe run after an elbow, a valve or a pump, or the sensor installation is not perfectly aligned with existing pipe line. In those scenarios, turbulence (swirl) or other type of secondary flow could cause errors with single-path flow meters.

The technical specification of the 280W-CI water meter meets the ISO 4064 (or OIML R49) water meter standards for Class D accuracy, and exceeds the AWWA C715 water meter standard. The operational temperature ranges from 0.1°C (32.2°F) to 60°C (140°F) including safety temperature up to 85°C. The large display can be set to display the flow total, flow rate, working time, leakage alarm, reverse flow, and more. The meter also has a remote readout which could be configured as pulse, M-Bus, RS485/Modbus, pulse, 4-20mA, BACnet, or, wireless.

Spire Metering’s 280W-CI Ultrasonic Water Meter stands out among the competition due to its rugged design, wide dynamic range, robust performance and extensive AMR functions. The 280W-CI performs reliably when the water has particulate or the environment is harsh. Both commercial and industrial installations can profit from the advantages of precision, wear-free water flow measurement, operational security and long service life.

The wPrime series ultrasonic water meter consists of a flow-cell, a pair of ultrasonic flow transducers and an integrator. The transducers are firmly mounted on the flowcell at the optimal position. As illustrated, the transducers face each other with one on the upstream, and the other on the downstream.

The integrator (or calculator) controls the two ultrasonic transducers to transmit and receive ultrasounds to conduct precise flow measurement. Specifically, it operates the two transducers which transmit a pulse of ultrasonic energy into the water flow toward the opposite transducer. The integrator detects the pulse signal which has traveled within the flow tube, and then is received by the opposite transducer. With advanced digital signal processing technology, the integrator precisely measures the arrival (or transit) time of each pulse signal.

Since the transit-time difference between the two pulses is directly proportional to flow velocity, it can calculate the flow velocity and flow rate. This is accomplished by combining it with the geometry of the flow-cell and fluid dynamics theory.

Only ultrasonic pulses are used to interrogate the flow which enables the meter to have no moving parts. Since the principle is based on the transit-time difference instead of transit-time, all the interfering factors, such as temperature, pressure, solids concentration and water quality, are cancelled out. The end result is an ultrasonic metering system which is inherently robust! Multi-path Technology

Multi-path Technology

In real application, it is not easy to install the flow sensor perfectly in line with the pipe line. A slight misalignment could cause flow profile distortion inside the flow sensor, and thus cause significant measurement errors. Spire Metering developed a unique multipath technology to solve this problem. Two or more pairs of ultrasonic transducers are mounted on the flow sensor body to interrogate the flow from four different paths. A flow calculation algorithm based on fluid dynamics theory is then used to derive an average flow reading with improved accuracy.

The wPrime series water meter offers a variety of interface options, such as M-Bus, pulse, RS485/ Modbus, BACnet, Pulse encoder, 4-20mA and wireless (GSM, GPRS and Radio). It is very flexible to be integrated into an AMR/AMI system.

Spire Metering also offers a complete range of AMR/AMI solutions as well as an integrated billing system. The SpireCapture system is a cutting edge fixed automatic meter reading system which integrates both wired and wireless AMR/AMI technologies. The system provides a unified platform for meter reading and data management through M-Bus networks, RF wireless networks, GSM/ GPRS cellular networks as well as TCP/IP networks. In addition, it works seamlessly with Spire Metering’s billing software to make data exchange fast, easy and reliable.

SpireCapture is an advanced, highly robust meter reading solution that delivers comprehensive usage information as well as timely, high-resolution meter reading. This data enables gas, water, heat and electric utilities to eliminate on-site visits and estimated reads, reduce theft and loss, implement time-of-use billing, and profit from all of the financial and operational benefits of fixed-network AMI/AMR.

Electrical Data

  • Power Supply: Battery, 3.6V, Lithium
  • Replacement Interval: 10 years at tBAT
  • Power Consumption: <0.1W
  • Backup Power Supply: Internal SuperCap
  • Communication Interface: M-Bus, Optional: long range Lora RF, pulse,
  • Encoder, GPRS, 4~20mA, Modbus, BACnet / MSTP
  • CE approval: EN61326-1:2006
  • Electromagnetic Class: E2

*Note: for OMS-compliant wMBus, please contact support@spiremt.com for details.

Accuracy / MPE (Maximum Permissible Error)

  • MPE according to OIML R49 / ISO4064
  • +/-2% in range Q2 ≤ Q < Q4; ±5 in range Q1 ≤ Q ≤ Q2

Metrology Data

  • Accuracy Class: 2 (according to ISO4064 / OIML R49)
  • Metrological Class: D (according to ISO4064 / OIML R49)
  • Range Q3/Q1: 250
  • Temperature Rating T30

Mechanical Data

  • Environmental Class: B. Optional A
  • Electromagnetic Class: E1
  • Environmental Temp: 0~55°C(32~131°F)
  • Permissible Flow Temp: 0.1~60°C (32.2~140°F) for permanent and up to 85°C (185°F) for short term
  • (
  • Enclosure Protection: IP68
  • Integrator Detachable: No
  • Lid Cover Protection: Yes
  • Pressure: PN16

Pressure Loss

The pressure loss of a flow sensor is proportional to the square on the flow : Δp = k x Q2 Here Δp is pressure loss, Q is volume flow rate and k is the coefficient. All meters have Δp less than 0.63bar at Q3, meet ISO4064 / OIML R49 standard and AWWA standard.

  • Optional Components (Choose One)
  • Output Interface Module (Must choose Serial TTL for the Base Unit Interface) Model No.
  • M-Bus Module: 280AP-MB
  • Pulse Module (dry contact, require 12~24VDC power): 280AP-P2
  • RS485 / Modbus Module: 280AP-MOD
  • 4-20mA & RS485 / Modbus Module: 280AP-MODAO
  • LoRa wireless endpoint with antenna for drive-by & AMI: 280AP-MR-LR2xxx (xxx = 1:433; 2:470; 3:866; 4:868; 5:915)
  • GPRS Cellular Module with 6 Years Battery in IP68 enclosure: Datakite-d10-GPRS
  • BACnet / MSTP Adapter: 280AP-MSTP

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