DigitalFlow™ GF868

Panametrics flare gas mass ultrasonic flowmeterwith extended performance range
Applications

Features

The DigitalFlow GF868 flowmeter is a complete ultrasonicflow metering system for:• Measures velocity, volumetric and mass flow

• Flare gas• Track down or prevent losses from leakage with positive
material identification• Account for total plant throughput of material• Reduce cost of steam and fuel usage withproportional control• Conserve energy by eliminating unnecessary flaring• Comply with government regulations for pollution control• Vent gas• Hydrocarbon gases• Biogases• Digester gases• Standard velocity range to 100 m/s (328 ft/s) standard• Extended velocity range to 120 m/s (394 ft/s)*• Measures instantaneous average molecular weight• Measures Net Heating Value (NHV) of vent gas in BTU/SCF,
MJ/m3, or KJ/m3• Measures hydrocarbon gases• Self-calibration check assures accurate worry-freeoperation• Delivers accurate flow rate, independent of gascomposition• Measures very low to very high velocity,
4000 to 1 turndown ratio• Field-proven installation techniques• Built-in totalizers• Built-in power supply for pressure and temperaturetransmitters• 4000 to 1 turndown ratio• One or two channel/path configurations* Velocity maximum may be higher in specific installations - consult with Panametrics

Flare gas mass flowmeter
The DigitalFlow GF868 ultrasonic flowmeter uses thepatented Correlation Transit-Time™ technique, digital
signal processing, and an accurate method of calculating
molecular weight. Add to these features the inherent
advantages of ultrasonic flow measurement reliability withno routine maintenance, high accuracy, fast response, andwide rangeability, the DigitalFlow GF868 flowmeter is theclear choice for flare gas applications.

mass flow rate. Temperature and pressure inputs enable themeter to calculate standard volumetric flow. For maximum
accuracy, use the two channel version and measure along
two different paths at the same location. The two-channel
meter can also measure the flow in two separate pipes or at
two different places on the same pipe.

Downstream
transducer

Correlation transit-time technology is ideal for
flare gas flow measurement
The correlation transit-time technique has distinct
advantages over other methods of flare gas flow
measurement, and it is used to solve a variety of difficult
problems. Typically, gas in flare stacks, headers or laterals
is a mixture of components from different sources. Flow rate
in flare systems may be unsteady or even bidirectional.
Pulsating pressure, varying composition and temperature,harsh environment, and wide flow range further complicate
the measurement. The GF868 is designed for superior
performance under these conditions.

Upstreamtransducer

Pressuretransmitter
Temperaturetransmitter

Digital analog
and alarm
outputs

PreamplifiersTypical meter set-up for standard volumetric or hydrocarbon mass flow

Patented molecular weight measurement method

Simple installation

The DigitalFlow GF868 uses a patented method for
calculating the average molecular weight of hydrocarbon
mixtures. This proprietary algorithm extends the range formeasuring average molecular weight, while improving
accuracy and compensating for non-hydrocarbon gases
better than ever before possible. Higher accuracy mass flow
data and more precise knowledge of flare gas composition
can improve the efficiency of plant operation, enablingcorrect metering of steam injection at the flare tip, rapid
troubleshooting of leaks into the flare stream, early detectionof process control problems, and accurate plant balance.

The flowmeter system consists of a pair of transducers foreach channel, preamplifiers, and an electronics console. The
transducers can be installed as part of a flowcell, or directly
into the pipe with a hot or cold-tapping procedure. The
electronics console of the DigitalFlow GF868 meter can belocated up to 1,000 ft (300 m) from the transducers.

Best technology for flare gas measurement
Ultrasonic flow measurement, the ideal technology for flare
gas applications, is independent of gas properties, and does
not interfere with the flow in any way. All-metal ultrasonictransducers installed in the pipe send sound pulses
upstream and downstream through the gas.
From the difference in these transit times between thetransducers, with and against the flow, the DigitalFlow GF868’s
on-board computer uses advanced signal processing andcorrelation detection to calculate velocity, and volumetric andStandard transducer mounting configurations

One meter, wide range offlow conditions
High flow
The DigitalFlow GF868 meter
achieves a new standard
rangeability of 3280 to 1 and a new
Extended Range rangeability of4000 to 1. It measures velocities
from 0.1 to 328 ft/s (0.03 to 100m/s) standard in both directions,while the Extended Range version
measures velocities to 394 ft/s (120m/s) in one direction, in steady or
rapidly changing flow, in pipes from 2 in to 120 in (50 mm to 3m) in diameter. With this range of operation, one DigitalFlow
GF868 flowmeter performs measurements under most of theconditions that may occur in a flare line on or offshore. Theextended velocity range to 100 m/s is enabled in standard
meters with no loss of accuracy.

Low flow
For base load operation the volumetric flow in flares isoften in the range 0.1 to 1 f/s (0.03 to 0.3 m/s) and the flaregas flowmeter improves the accuracy over that range, but
still measures at high velocity during facility relief or upset
conditions. Additional paths, longer paths, unconventional
configurations and location of paths are used to achieve
accurate low flow measurements. A single path or two pathmeter can be selected and optimized to meet both high flow
and low flow measurement requirements.

Flowdirection

Energy measurement
Latency in measuring the energy content of a flare gas canlead to poor combustion efficiency or fuel gas waste at
the flare tip. This can lead to excessive emissions, mostly
harmful methane, into the atmosphere, risking increased
fine associated with non-compliance and greater negative
impact on the climate. The model GF868 has an option
for measuring the net heating value (NHV) of the flare gas
to help operators optimize their assist flares to providea smokeless flame and maintain a high combustion
efficiency without the latency issues or the installation andmaintenance costs of a separate analyzer. For increased
capabilities unlocking the full potential of reduced emissions
and flare control and optimization, use a GF868 or an XGF868
with flare.IQ advanced control solution.

Identify leak sources, reduce steam usage andimprove plant material balance
Leaks and excess steam delivery are two major causes ofloss of product and energy. Reducing them immediately
improves the overall efficiency in refinery and chemicalplant operation. Payback for the entire DigitalFlow GF868
installation usually occurs within a matter of months.
The DigitalFlow GF868 can help save millions of dollars in
reduced losses.
Once the sound speed of the gas has been determinedby the DigitalFlow GF868, its on-board computer uses
temperature and pressure inputs in conjunction with thesound speed to calculate instantaneous average molecularweight and mass flow rate of the gas. These parameters
are used to help identify sources of leaks into the flaresystem. Detection of even a small increase in flow rate
into the flare system may indicate a leak source such as
partially unseated relief valve. An accompanying change
in the average molecular weight of the flare gas may be
used to help locate the leak source. Quick identificationand elimination of leak sources into the flare system saves
significant amounts of potentially lost energy and product.
Mass flow rate may be used to perform a mass balancecalculation and to control flare tip steam injection. By
knowing the exact amount of gas flow and averagemolecular weight in the flare stack, delivery of the correct
amount of steam required at the flare tip can be accuratelycontrolled. Steam usage can be reduced while maintaining
compliance with pollution control regulations.

Designed for flare gas environment
The DigitalFlow GF868 flowmeter has no moving parts toclog or wear out. Its patented ultrasonic transducers areconstructed of titanium or other metals that withstand thecorrosive environment usually found in flare gas applications.
The transducers are designed for use in hazardous locations.
Wide rangeability allows measurement of flow rate from
0.1 up to 394 ft/s (0.03 to 120 m/s). In contrast to thermal
flowmeters, the ultrasonic transit-time technique does notdepend on the heat transfer coefficient of the flare gas anddoes not require regular maintenance. These and otherfeatures make the DigitalFlow GF868 unique among flare gas
flowmeters.

Self-calibration check for worry free operation
The DigitalFlow GF868 meter will perform daily heath checks
using our proprietary algorithm, at the predetermined
flowrates and hour chosen by operators. Depending on theself-health check result, the meter will output a PASS if themeter is working correctly or a FAIL if there is any criticalfailure. In the case of a problem, this will allow operators
to know the status of the meter ahead of time and takeactions accordingly. In addition, this will give regulatory
authorities and meter operators confidence that the meter isfunctioning reliably and accurately.

GF868 specifications• Four outputs with 1000 Ohm maximum load

Electronics

Optional inputs/outputs

Flow measurement
Patented Correlation Transit-Time mode
Enclosures

Namur NE43 compliant
There are four additional slots available for any combinationof the following I/O boards:• Analog output board with four isolated 0/4 to 20 mAoutputs, 1 kOhms maximum load

• Standard: Epoxy-coated aluminum weatherproof Type• Analog input board, two types
4X/ IP66 								 •	With two isolated 4 to 20 mA inputs and 24V loop power
Can be configured for Class I, Division 2, Groups ABCD,NEC & CEC• With two isolated, three-wire, 100 Ohms RTD inputs; span–148°F to 662°F (–100°C to 350°C);• Optional: Stainless steel, weatherproof Type 4X/ IP66
Can be configured for Class I, Division 2, Groups ABCD,• Totalizer/frequency output board
NEC & CEC 						• With four outputs per board, 10-kHz maximum.
Explosion proof 					• Software-selectable functioning in two modes
Class I, Division 1, Groups BCD, NEC & CEC Ex d IIC T6 Gb, IECEx& ATEX (II 2G)• Totalizer mode: Pulse per defined unit of parameter (e.g., 1Dimensions• Weight 11 lb (5 kg)• Size (h x w x d) 14.24 in x 11.4 in x 5.12 in(362 mm x 290 mm x 130 mm)
Channels• Standard: One channel• Optional: Two channels (for two pipes or two path averaging)
Display
Two independent software-configurable 64 x 128 pixel backlit
LCD graphic displays
Keypad39-key tactile-feedback membrane
Power supplies• Standard: 100 to 130 VAC, 50/60 Hz or 200 to 240 VAC,
50/60 Hz• Optional: 12 to 28 VDC, ±5%Note: For DC-powered meters, Class 2 rated supplies must be used for the line power.

Power consumption
20W maximum
Operating temperature–4°F to 131°F (–20°C to 55°C)
Storage temperature–67°F to 167°F (–55°C to 75°C)
Standard inputs
Two isolated 0/4 to 20 mA inputs (121 Ohm) supports 24VDC
loop-powered devices.
Namur NE 43 compliant
For required temperature and pressure inputs

Standard outputs• Six 4 to 20 mA outputs, software assignable• Two outputs with 550 Ohms maximum load

pulse/ft3 or 1 pulse/0.028 m3)• Frequency mode: frequency proportional to rate ofparameter (e.g., 10 Hz = 1 ft3/h or 0.028 m3/h)• Alarm relay board with three hermetically sealed Form C
relays; 120 VAC, 28 VDC maximum, 2A maximum; DC 56Wmaximum, AC 60 VA
Digital interfaces• Standard: RS232• Optional: RS485 (multiuser)• Optional: HART®7 protocol• Optional: Modbus® RS485 or TCP/IP• Optional: Ethernet TCP/IP• Optional: OPC server• Optional: Foundation Fieldbus Namur NE107 Compliant
Site parameter programming
Menu-driven operator interface using keypad and “soft”
function keys
Data logging
Memory capacity (linear and/or circular type) to log morethan 43,000 flow data points
Display functions• Graphic display shows flow in numerical or graphic format• Displays logged data and diagnostics
European compliance
Complies with• 2014/30/EU EMC - Industrial EM Environments• 2014/35/EU LVD - Equipment Class I, Pollution Degree 2,Overvoltage Category II• 2014/34/EU ATEX (optional) - II 2G• The GF868 is intended for inclusion in large-scale fixedinstallations (LSFI) and are therefore outside of the scope ofDirective 2011/65/EU RoHS.

T5MAX wetted flow ultrasonictransducers

Insertion mechanism

Pressure range
Standard: -2 psig to 1500 psig (87.6 to 10300 kPa)

Preamplifier

Temperature range
Normal Temperature (NT): -55 C to 150 C

Transducer Material
Standard: Titanium
Optional: Hastelloy alloys or SS316 (Consult factory)
Process connections
Flanged and compression fittings
Hazardous Area classifications
Explosive-proof Class I, Division 1, CD
Optional: Group B upon request
Ex d IIC T6..T3 Gb, IECEx & ATEX (II 2G)
An integrated XAMP preamplifier may be installed in thecertified assembly.

T5/T17 wetted flow ultrasonictransducers

Standard and extended range
2 in (50 mm) and 3 in (76mm) flange mounted packing
gland and valve.

In-line XAMP preamplifier with BNC connections; one pertransducer.
Gain• Standard: 20 and 40• Optional: 2 and 10 (factory selected)
Preamp temperature range:-40°C to +60°C (-40°F to +140°F)
Location
Installation of the XAMP in the transducer assembly iscovered by the transducer’s hazardous area certification,subject to the above temperature limits.
Alternately, the XAMP may be installed separate from thetransducer – remote mounted – with the following rating.
Explosion-proof Class I, Division 1, CD or BCD

Temperature ranges
Normal Temperature (NT): -55°C to 150°C
Low Temperature (LT): -220°C to 100°C
High Temperature (HT): -50°C to 250°C
Extremely High Temperature (XT): -180°C to 300°C

Ex d IIC T6 Gb, IECEx & ATEX (II 2G)Pressure range
Standard: -2 psig to 1500 psig (87.6 to 10300 kPa)

• One pair of coaxial cables, type RG62 A/U, preamplifier toGF868 electronics, lengths 3 m (10 ft) to 330 m (1000 ft)
maximum

Transducer materials• Standard: Titanium• Optional: Monel® or Hastelloy® alloys or SS316

Transducer cables• Standard: (per pair of transducers)• Optional: flame retardant, armored cable

Process connections
Flanged and compression fittings

Additional options

Hazardous Area classifications
Explosion-proof Class I, Div. 1, CD
Optional: Group B upon request
II 2G Ex d IIC T6..T2 Gb, IECEx & ATEX (II 2G)
An integrated XAMP preamplifier may be installed in thecertified assembly.

The DigitalFlow GF868 communicates with a PC through aserial interface and Windows® operating systems. Features
include site files, logs and other operations with a PC.
Installation flowcells

PanaView™ PC-interface software

Transducers and flowcells for specific applications areavailable. Consult Panametrics for details.
Flare control and optimization
Consult Panametrics for details about flare control andoptimization using flare.IQ as a solution for compliance toemission regulations (such as RSR MACT 63.670) and for
efficient steam control to save cost.

Flow accuracy
Transducer typeT5 wetted transducer

Number of paths

One path

T17/T5MAX (see note 1)
Two paths

One path

Two paths

Flow measurement range
Standard range-328 to 328 ft/s (-100 to 100 m/s) - bidirectional

Extended range.1 to 394 ft/s (0.03 to 120 m/s) - non-bidirectional
Applicable pipe sizes

Diagonal 45

3 in to 14 in (50 to 350 mm) OD

14 in to 120 in (350 to 3000 mm) OD

Bias 90

Note 2 & 3

Not ApplicableDesign velocity accuracy from 1 to 394 ft/s (0.3 to 120 m/s) - refer to notes 2 and 3 below
Transducer typeT5 wetted transducer

Number of paths

One path

T17/T5MAX Wetted Transducer
Two paths

One path

Two paths

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)Pipe Dia. </= 6 in. (150mm)

±2.5%

±2.0%

±2.0%

±1.5%

NANANANA

Pipe Dia. >/= 6 in (150mm)

±2.0%

±2.0%

±1.5%

±1.5%

±2.0%

±2.0

±1.5%

±1.5%

Calibrated velocity accuracy from 1 to 394 ft/s (0.3 to 120 m/s) — refer to notes 2 and 3 below
Transducer type

T5 Wetted Transducer

Number of paths

One path

T17/T5MAX Wetted Transducer

Two paths

One path

Two paths

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)

1 ft/s(0.3 m/s)>3 ft/s(1 m/s)Pipe Dia. </= 6 in. (150mm)

±1.5%

±1.0%

±1.0%

±0.75%NANANANA

Pipe Dia. >/= 6 in (150mm)

±1.0%

±1.0%

±0.75%±0.75%±1.0%±1.0±0.75%±0.75%

Mass flow accuracy
2 to 120 kg

±4.0%

±3.1%

±2.7%

±2.3%

Molecular weight accuracy
2 to 120 kg/kmole±1.8% to ±2%
Net Heating Value (NHV) accuracy - refer to note 4

Typical accuracy

2% - 5%
Flow velocity sensitivity from .1 to 1 ft/s (0.03 to .3 m/s)

Pipe Dia. = 10 in. (250mm)±0.12 in/s(±0.004 m/s)

±0.08 in/s( ±0.003 m/s)

NA

NA

Pipe Dia. = 14 in. (250mm)±0.12 in/s(±0.004 m/s)

±0.08 in/s( ±0.003 m/s)

±0.08 in/s(±0.003 m/s)

±0.06 in/s( ±0.002 m/s)

Pipe Dia. >/= 20 in. (500mm)±0.12 in/s(±0.004 m/s)

±0.08 in/s( ±0.003 m/s)

±0.06 in/s( ±0.002 m/s)

±0.04 in/s(±0.0015 m/s)

Repeatability±0.5% at 1 to 394 ft/s (30 cm/s to 120 m/s). Consult factory for details.

General installation straight run requirement
20D upstream and 5D downstream without CFD analysis.
5D upstream and 2D downstream with CFD analysis. Consult factory for details.
Note 1: T17 available in NT/HT/LT/XT; T5MAX only available in NT.
Note 2: Accuracy and sensitivity are dependent on pipe diameter, molecular weight and temperature. All accuracy specs
assume molecular weights greater than 24 kg/kmole and temperatures less than 100 °F (38 °C)
Note 3: All accuracy specs assume a fully developed flow profile. This typically requires 20D upstream and 5Ddownstream. Desired accuracy can also be achieved with shorter straight runs as little as 5D upstream and 2D
downstream through correction factors from Computational Fluid Dynamics (CFD) analysis loaded to GF868 meters.
Consult factory for details.
Note 4: Assuming known N2 concentration. Consult factory for details.

Panametrics, a Baker Hughes business, provides solutions inthe toughest applications and environments for moisture,oxygen, liquid and gas flow measurement.
Experts in flare management, Panametrics technology also
reduces flare emissions and optimizes performance.
With a reach that extends across the globe, Panametrics’
critical measurement solutions and flare emissions
management are enabling customers to drive efficiency
and achieve carbon reduction targets across criticalindustries including: Oil & Gas; Energy; Healthcare; Water andWastewater; Chemical Processing; Food & Beverage andmany others.
Join the conversation and follow us on LinkedIn
linkedin.com/company/panametricscompany

Copyright 2024 Baker Hughes Company. All rights reserved.
BHCS38521		

(01/2024)

panametrics.com