E&H 9G3B ultrasonic flowmeter

E&H 9G3B ultrasonic flowmeter

Introduction: The Process Gas Measurement Specialist

The Endress+Hauser Proline Prosonic Flow G 300, designated under the product root 9G3B, represents the culmination of decades of ultrasonic measurement expertise applied to the most demanding gas applications in the oil & gas and chemical industries. Whether measuring raw natural gas, processed gas, coal seam gas, shale gas, wet biogas, or complex industrial gas mixtures, the E&H 9G3B ultrasonic flowmeter delivers laboratory-grade accuracy in harsh industrial environments.

Unlike conventional gas flow metering technologies that struggle with fluctuating gas compositions or wet gas conditions, the 9G3B series employs a transit-time ultrasonic measurement principle that remains fundamentally unaffected by changes in gas properties. This inherent robustness, combined with multivariable measurement capabilities and Heartbeat Technology, transforms a simple flowmeter into a comprehensive gas analysis and process monitoring platform.

For operators of natural gas pipelines, chemical processing plants, biogas facilities, and custody transfer applications, the E&H 9G3B ultrasonic flowmeter provides the reliability and intelligence required for 21st-century gas measurement.

Key Technical Specifications at a Glance

Accuracy Specifications

Maximum achievable measuring accuracy: 0.5 % with optional calibration-1.

Wetted Materials

All wetted materials are compliant with NACE MR0175/MR0103, ensuring compatibility with sour gas applications containing hydrogen sulfide.

Eight Sub-Models: The Complete 9G3B Product Family

The E&H 9G3B ultrasonic flowmeter series is organized into eight distinct product variants, each engineered for specific pipe diameters, path configurations, and application requirements. Understanding these sub-models is essential for correct device specification.

9G3B25 – DN 25 (1″) Entry-Level Configuration

The 9G3B25 represents the smallest nominal diameter offering in the G300 series, designed for DN 25 pipelines (1-inch). This compact variant is ideal for smaller gas lines, pilot-scale processes, skid-mounted systems, and applications where space constraints are critical. Despite its minimal footprint, the 9G3B25 delivers the full measurement capability of the series: volume flow, corrected volume flow, mass flow, flow velocity, speed of sound, pressure, temperature, density, dynamic viscosity, energy flow, Wobbe index, methane fraction, calorific value, and molar mass-9. A documented stock configuration, 9G3B25-BDDMABAGADACEABSAA2ADEF, is available with a manufacturer list price of $18,292.85-36.

9G3B50 – DN 50 (2″) Small-Line Configuration

The 9G3B50 serves the DN 50 (2-inch) market segment, offering a balance between compact size and flow capacity. This variant is frequently specified for process gas lines in chemical plants, natural gas distribution branches, and biogas collection headers. The 9G3B50 is available in multiple stock configurations, including 9G3B50-CDEBABDOADACDAASDA2AADEEFJAJBK674 and 9G3B50-CSIMADAGADACEAASAA2EBEF with stock levels of 10 units, priced at $13,348.97-36.

9G3B80 – DN 80 (3″) Medium-Line Configuration

The 9G3B80 addresses DN 80 (3-inch) pipeline applications, representing the upper end of the small-bore range before transitioning to two-path configurations. This variant is ideal for medium-flow natural gas metering, process gas monitoring in chemical reactors, and industrial gas distribution. A readily available configuration, 9G3B80-CDDMADAGADACDAASAA2EF, is stocked with three units at $19,888.96-36.

9G3B1H – Two-Path High-Performance for DN 100

The 9G3B1H introduces two-path ultrasonic measurement technology, delivering enhanced accuracy and redundancy for DN 100 pipelines (4-inch nominal diameter). The dual-path configuration improves measurement performance in challenging flow profiles, making the 9G3B1H particularly suitable for main natural gas headers, custody transfer applications requiring SIL certification, and process gas lines with complex flow regimes. The two-path design also provides built-in redundancy, ensuring continued operation if one acoustic path experiences signal degradation.

9G3B1F – Two-Path Flanged Configuration for DN 150

The 9G3B1F is specified for DN 150 pipelines (6-inch nominal diameter). This two-path variant combines the accuracy benefits of dual-path technology with flanged process connections for secure, leak-free installation. A documented configuration, 9G3B1F-CSIBABBFADAAAACSAA2AAJBLR, is available with a configured price of $20,734.81 and typical lead time of 2-3 weeks-.

9G3B2H – Two-Path High-Performance for DN 200

The 9G3B2H addresses DN 200 pipelines (8-inch nominal diameter). This configuration is designed for high-volume natural gas transmission, large-scale chemical processing, and industrial gas distribution networks. The 9G3B2H maintains the full 0.5% accuracy specification across the entire flow range while handling significantly higher volumetric flow rates.

9G3B2F – Two-Path Flanged Configuration for DN 250

The 9G3B2F is engineered for DN 250 pipelines (10-inch nominal diameter). This two-path flanged variant is specified for large-diameter gas transmission lines, compressor station inlets and outlets, and industrial gas distribution systems requiring robust mechanical connections. A documented stock configuration, 9G3B2F-CDEBADDFADACEAASAA2, is available with a manufacturer list price of $29,652.23-36.

9G3B3H – Two-Path High-Performance for DN 300

The 9G3B3H represents the largest offering in the G300 series, engineered for DN 300 pipelines (12-inch nominal diameter). This two-path high-performance configuration is designed for the most demanding high-volume gas applications, including main natural gas transmission lines, large-scale chemical plants, and centralized biogas upgrading facilities. The 9G3B3H maintains the exceptional 0.5% accuracy specification even at the highest flow rates, delivering reliable measurement for billing, allocation, and process control purposes.

Complete Order Code Breakdown: 9G3B25-BBECAAAFAAAAAAASAA2

Endress+Hauser employs a structured order code system that encodes all device features and configuration options into a compact alphanumeric string. Understanding this structure enables engineers and procurement specialists to verify configurations, order spare parts, and ensure specification compliance.

Below is a detailed breakdown of the order code 9G3B25-BBECAAAFAAAAAAASAA2:

When ordering or verifying device configurations, users can enter the complete order code into the Endress+Hauser W@M Device Viewer to retrieve full documentation, spare parts lists, and device-specific information. The product root 9G3B is the first part of any order code and uniquely identifies the G300 series-26.

Core Technology: Ultrasonic Transit Time for Gas

The Prosonic Flow G 300 operates on the ultrasonic transit time principle, a measurement technique that has been proven in thousands of gas measurement installations worldwide. Two ultrasonic transducers are mounted on opposite sides of the measuring tube at a specific angle. The flowmeter alternately transmits ultrasonic signals in both directions—upstream and downstream. The transit time of the signal traveling with the flow is shorter than that of the signal traveling against it. This time difference (Δt) is directly proportional to the average flow velocity of the gas.

What makes this principle revolutionary for process gas applications is its immunity to gas composition variations. Unlike thermal mass flowmeters, which require knowledge of gas properties, or differential pressure devices, which are affected by density changes, the ultrasonic measurement principle delivers reliable readings regardless of whether the gas contains varying levels of methane, carbon dioxide, nitrogen, hydrogen, or moisture.

The E&H 9G3B ultrasonic flowmeter delivers consistent performance across:

Raw natural gas (varying methane content)

Process gas (chemical plant byproducts)

Coal seam gas (variable CO₂ content)

Shale gas (composition fluctuations)

Wet biogas and digester gas

Industrial gas mixtures with up to 8 user-defined components

Integrated Gas Analysis Functions

Perhaps the most compelling feature of the E&H 9G3B ultrasonic flowmeter series is its advanced gas analysis capability, which transforms the device from a simple flowmeter into a comprehensive gas quality analyzer.

The physics underlying this capability is both elegant and powerful: the speed of sound in a gas is a function of its temperature, pressure, and molecular composition. The Prosonic Flow G 300 precisely measures flow velocity, speed of sound, pressure (with optional integrated pressure cell), and temperature. Using these direct measurements, the device calculates a comprehensive suite of derived process variables:

Directly measured variables:

Volume flow

Flow velocity

Speed of sound (±0.2 % o.r. accuracy)

Pressure (with integrated pressure cell)

Temperature (with optional AFM 34 sensor)

Derived variables (advanced gas analysis):

Corrected volume flow (referenced to standard conditions)

Mass flow

Density

Dynamic viscosity

Energy flow

Wobbe index (critical for gas quality and interchangeability)

Methane fraction (CH₄ content)

Calorific value (heating value)

Molar mass

For applications requiring custom gas mixtures, the G300 allows user definition of up to eight gas components, enabling precise calculation of all derived variables for proprietary process gases or non-standard compositions-20.

Condensate-Insensitive Sensor Design

A persistent challenge in gas flow measurement is the presence of condensate—liquid droplets that can accumulate on sensor surfaces and degrade measurement performance. The 9G3B series addresses this challenge with a sensor design specifically engineered for condensate insensitivity.

The robust industrial design maintains measurement reliability even with humid or wet gases, ensuring that the presence of moisture does not compromise accuracy or cause signal loss-12. This is particularly critical in:

Natural gas transmission (water vapor content)

Biogas applications (saturated at 100% relative humidity)

Landfill gas extraction (variable moisture levels)

Compressor station operations (condensate formation)

Integrated Pressure and Temperature Measurement

The E&H 9G3B ultrasonic flowmeter can be ordered with a built-in pressure cell and optional temperature sensor, providing all three measurement variables—flow, pressure, and temperature—from a single process penetration.

This integrated approach delivers several significant advantages:

Reduced installation complexity – Single process connection instead of separate flow, pressure, and temperature devices

Real-time compensation – Corrected volume flow calculated instantaneously using live pressure and temperature values

Lower procurement costs – Single device cost versus three separate instruments

Reduced leak paths – Fewer process penetrations mean fewer potential leak points

Simplified documentation – Single device verification instead of three separate calibration records

When the integrated pressure cell is specified, the medium temperature range is limited to –50 to +100 °C (–58 to +212 °F)-1. For applications requiring the full –50 to +150 °C temperature range, the pressure cell option is omitted.

Heartbeat Technology: Integrated Verification

Endress+Hauser’s patented Heartbeat Technology is embedded within the 9G3B series, providing continuous self-diagnostics and on-demand verification without process interruption-9. This capability enables:

Continuous self-monitoring of sensor and electronics health with diagnostic coverage exceeding 95%

On-demand verification of meter accuracy against factory specifications without removing the device from service

Documentation-ready reports for regulatory compliance, quality audits, and SIL certification requirements

Predictive maintenance alerts before failures occur, enabling planned interventions rather than unplanned shutdowns

The verification functionality has been certified by TÜV SÜD for metrologically traceable device verification without process interruption-20. For natural gas custody transfer, emissions reporting, and carbon credit verification applications, Heartbeat Technology provides the auditable traceability required for compliance while eliminating costly off-line calibration.

Pressure-Rated Sensor Housing with Rupture Disc

Safety is paramount in gas measurement applications, where overpressure events can have catastrophic consequences. The 9G3B series features a pressure-rated sensor housing equipped with a rupture disc that limits safety risks in the event of an internal overpressure condition-13.

The entire sensor housing is constructed from corrosion-resistant stainless steel, making the E&H 9G3B ultrasonic flowmeter especially suited for harsh ambient conditions, including offshore platforms, marine environments, and chemically aggressive industrial atmospheres-20.

Flexible Transmitter and Connectivity

The compact dual-compartment transmitter of the 9G3B series offers exceptional flexibility in operation and system integration:

Access and operation:

Backlit 4-line illuminated display with touch control (operation from outside the device)

WLAN access for remote configuration and diagnostics

Remote display available for mounting up to 20 meters from the sensor

Inputs and outputs:

Up to 3 I/Os in a compact dual-compartment housing

Freely configurable I/O functionality for reduced complexity

Digital communication options: HART (standard), Modbus RS485

Power supply:

24 VDC for loop-powered 4-20 mA HART operation

100-230 VAC for high-power configurations

SIL Certification for Safety-Related Applications

The Prosonic Flow G 300 has been developed to IEC 61508 (SIL) standards, making the E&H 9G3B ultrasonic flowmeter suitable for safety-related applications-20. SIL certification ensures that the device meets rigorous requirements for systematic capability, random hardware integrity, and architectural constraints.

SIL-rated applications for the G300 series include:

Overfill protection in gas storage systems

High-pressure shutdown in compressor stations

Emergency venting monitoring

Safety instrumented functions (SIF) requiring flow measurement

When combined with Heartbeat Technology, the SIL-rated G300 provides both the functional safety required for protection applications and the diagnostic coverage needed to maintain safety integrity over time.

Environmental and Operating Conditions Summary

Model Comparison Summary

Ordering and Configuration Resources

Endress+Hauser provides several online tools to assist with device selection and configuration:

W@M Device Viewer (www.endress.com/deviceviewer): Enter the order code or serial number to access complete device documentation, spare parts lists, and technical drawings

Applicator sizing tool: For correct product selection and sizing based on specific process conditions, including gas composition, flow rates, and pressure ranges

Offline Configurator: For product configuration, quote generation, and export to procurement systems

Documentation for the 9G3B series is available for download from the Endress+Hauser website, including:

Technical Information (TI01385D)

Operating Instructions (BA01834D for HART, BA01835D for Modbus RS485)

Safety Instructions (KA01374D, KA01375D, KA01376D)