Panametrics DigitalFlow GM868 General-Purpose Gas Ultrasonic Flowmeter
Overview
The Panametrics GM868 — officially the Panametrics DigitalFlow GM868 — is a general-purpose gas ultrasonic flowmeter engineered by Panametrics, a Baker Hughes business, for accurate and reliable volumetric and mass flow measurement across an exceptionally wide range of pipe sizes and gas compositions. Built on the patented Correlation Transit-Time™ method of ultrasonic flow measurement, the GM868 provides drift-free readings without impeding or obstructing the gas stream in any way. Its clamp-free, non-intrusive transducer design allows one meter to do the work of several conventional instruments, covering pipes from 1 to 120 inches (2.5 cm to 3 m) in diameter and flow velocities from 0.1 to 150 ft/s (0.03 to 46 m/s) in either direction, whether the flow is steady or pulsating.
As the official authorized partner and exclusive regional representative for Panametrics and Baker Hughes instrumentation, Seven Star LLC proudly supplies the Panametrics DigitalFlow GM868 to process plants, gas utilities, and industrial facilities across Oman and the wider GCC. Engineers in Muscat, Sohar, and Salalah rely on Seven Star LLC for genuine Baker Hughes flow metering hardware, complete with full manufacturer warranty, application engineering support, and locally stocked spares that keep flare, vent, and process gas measurement points running without costly import delays.
Measurement Principle
The Panametrics GM868 measures gas flow using the transit-time ultrasonic method, in which paired ultrasonic transducers are mounted diagonally across a pipe or flow cell, one upstream and one downstream of the flow direction. Sound pulses are transmitted alternately in both directions along the same acoustic path; the pulse travelling with the flow arrives faster than the pulse travelling against it. The Panametrics GM868’s Correlation Transit-Time algorithm calculates this time difference with exceptional precision, deriving the average gas velocity along the path and converting it into standard or actual volumetric flow, mass flow, and totalized flow using entered or measured process conditions.
Because the wide-range transducers introduce nothing into the gas stream beyond the acoustic pulse itself, the GM868 causes no pressure drop and has no parts that foul, wear, or require lubrication. This non-obstructive architecture makes it inherently tolerant of dirty, contaminated, or particulate-laden gas streams that would degrade mechanical meters, while the wide rangeability — a turndown ratio of 1500 to 1 — lets a single meter cover startup, turndown, and peak-load conditions without recalibration. Two-channel and two-path configurations are available for applications demanding the highest achievable accuracy or for simultaneously monitoring two separate pipes.
Engineering Design of the Panametrics GM868
The Panametrics GM868 is housed in an epoxy-coated aluminum enclosure rated Type 4X/IP66, with hazardous-area variants certified Class I, Division 1, Groups B, C and D, and flameproof options meeting ATEX II 2 GD EEx d IIC T5 IP66. An optional stainless steel enclosure is available for corrosive coastal and offshore installations common across GCC oil and gas terminals. The standard transmitter measures 8.2 in x 6.6 in (208 mm x 168 mm) and weighs approximately 10 lb (4.5 kg), with a built-in infrared six-button keypad enabling full field configuration without opening the enclosure, and an optional two-line by sixteen-character backlit LCD display for local readout of up to four measurement parameters in sequence.
Field wiring is straightforward: standard 100–240 VAC power (12 to 28 VDC optional) feeds the electronics at a maximum draw of 20 W, while two isolated 0/4–20 mA outputs, Namur NE043-compliant, ship as standard. Up to six additional I/O slots accept analog input boards, RTD input boards, totalizer/frequency output boards, and general-purpose or hermetically sealed alarm relay boards, giving integrators flexibility to match the GM868 to existing SCADA and DCS architectures. Digital communication options extend from standard RS232 to optional RS485 (Modbus RTU or TCP), Ethernet, OPC server, and Foundation Fieldbus, while transducer cabling runs up to 1,000 ft (330 m) using coaxial RG62 AU cable, allowing the electronics to be mounted safely away from hazardous or high-temperature zones.
Key Features
The Panametrics GM868 gas ultrasonic flowmeter combines wide-range coverage with rugged, low-maintenance construction suited to demanding industrial gas applications.
- The Panametrics GM868 delivers Correlation Transit-Time™ ultrasonic measurement with drift-free accuracy of ±1% to 2% of reading, improvable to ±0.5% with process calibration.
- Covers pipe sizes from 2 in to 120 in (50 mm to 3,000 mm) and bidirectional flow velocities from –150 to 150 ft/s (–46 to 46 m/s).
- Non-obstructive transducers cause zero pressure drop and require no lubrication, cleaning, or routine maintenance.
- Transducers are removable under line pressure, allowing service without shutting down the process.
- 1500:1 turndown ratio provides accurate readings across a wide range of flow conditions from a single instrument.
- Standard and optional configurations support hazardous-area classifications including explosion-proof and flameproof enclosures.
- On the Panametrics GM868, optional two-path measurement doubles acoustic sampling for maximum accuracy on critical custody-adjacent or balance metering points.
- Wide digital interface support — RS232, RS485, Modbus, Ethernet, OPC and Foundation Fieldbus — simplifies integration into existing plant control systems.
Industrial Applications
The Panametrics GM868 is deployed across hydrocarbon gas measurement, vent and flare gas monitoring, biogas and digester gas metering at wastewater treatment plants, fuel gas supply lines, waste gas and incinerator air flow monitoring, vapor recovery units, and stack gas measurement. Its tolerance for dirty, particulate-laden, or pulsating gas streams makes it especially valuable in upstream gas processing, gas gathering stations, and refinery utility systems where mechanical meters would quickly foul or require frequent recalibration. In Oman’s LNG, gas processing, and petrochemical sectors, the Panametrics GM868’s wide turndown and non-intrusive design reduce both installation complexity and long-term maintenance cost.
As the officially authorized partner for Panametrics and Baker Hughes, Seven Star LLC distributes the Panametrics GM868 (DigitalFlow GM868) to gas processing plants, refineries, and industrial facilities throughout Oman, the Sultanate’s Sohar and Salalah economic zones, and across the broader GCC. Local engineering support, genuine spare transducers, and factory-backed calibration services ensure that flare gas, vent gas, and process gas measurement points in Muscat and beyond remain compliant with environmental reporting requirements and plant efficiency targets.
Technical Specifications
The table below summarizes the key specifications of the Panametrics GM868 ultrasonic gas flowmeter.
| Parameter | Specification |
|---|---|
| Model | Panametrics GM868 (DigitalFlow GM868) |
| Measurement Method | Correlation Transit-Time™ ultrasonic |
| Fluid Types | All acoustically conductive gases |
| Pipe Sizes | 2 in to 120 in (50 mm to 3,000 mm) NB and larger |
| Flow Accuracy (Velocity) | ±1% to 2% of reading typical; to ±0.5% with process calibration |
| Repeatability | ±0.2% to 0.5% of reading |
| Range (Bidirectional) | –150 to 150 ft/s (–46 to 46 m/s) |
| Rangeability (Turndown) | 1500:1 |
| Enclosure | Epoxy-coated aluminum, Type 4X/IP66; optional stainless steel |
| Hazardous Area Rating | Class I, Division 1, Groups B, C & D; ATEX II 2 GD EEx d IIC T5 IP66 |
| Power Supply | 100–240 VAC standard; 12–28 VDC optional |
| Power Consumption | 20 W maximum |
| Operating Temperature | –4°F to 131°F (–20°C to 55°C) |
| Standard Outputs | Two 0/4–20 mA isolated outputs, Namur NE043 compliant |
| Digital Interfaces | RS232 standard; RS485/Modbus, Ethernet, OPC, Foundation Fieldbus optional |
| Dimensions / Weight | 8.2 in x 6.6 in (208 mm x 168 mm), 10 lb (4.5 kg) |
| Transducer Cable | Coaxial RG62 AU, up to 1,000 ft (330 m) |
Request a Quote for Panametrics DigitalFlow GM868 General-Purpose Gas Ultrasonic Flowmeter
To specify the Panametrics GM868 for a new gas measurement point or to replace an aging mechanical meter, contact the Seven Star LLC instrumentation division for a formal RFQ, technical datasheet, and application review. As the authorized partner for Panametrics and Baker Hughes in Oman and the GCC, Seven Star LLC maintains regional warehouse stock of flow transmitters and transducers, backed by factory training and calibration support, so that plants in Muscat, Sohar, Salalah, and across the Sultanate can deploy genuine Baker Hughes flow metering technology with confidence and minimal lead time.
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