DigitalFlow™ GS868

Panametrics ultrasonic steam mass flowmeter
Applications

Features

The DigitalFlow GS868 steam ultrasonic flowmeter is acomplete ultrasonic flow metering system that measuressaturated or superheated steam for:• Bidirectional• Heating, ventilating and air conditioning (HVAC)• Pneumatic power systems• Food and beverage industry• Water purification and distillation• Chemical and petrochemical industries• Electric power generation• Steel industry• Public works• Manufacturing• No moving parts• No pressure drop
• Wide rangeability with 1500 to 1 turndown ratio• Non-obstructive flow measurement• Tolerance to dirty streams• Low maintenance• Suitable for high temperatures• Two-path measurement available for maximum accuracy

Panametrics ultrasonic steam mass flowmeter
The DigitalFlow GS868 steam ultrasonic flowmeter is designed
to measure the mass flow rate of saturated or superheatedsteam. It offers a unique combination of no pressure drop,
wide rangeability, ease of installation, low maintenance andhigh accuracy in a full-feature flowmeter package.

The DigitalFlow GS868 flowmeter uses
the correlation Transit-Time™ technique
Compact ultrasonic transducers are installed in the pipeor duct, one upstream of the other. The transducers send
and receive ultrasonic pulses through the steam. The
meter measures the difference between the upstream anddownstream transit times, and uses digital signal processing,advanced signal processing and correlation detection to
calculate velocity and volumetric flow rate. Mass flow is
calculated from the input of temperature and pressure
and the built-in steam tables.

No pressure drop, low maintenanceIn addition to the standard single-channel model, an
optional two-channel model provides enhanced accuracy
when measuring two paths on a single pipe. It can also be
used to measure a single path on two pipes.

Low operational costs
Conventional steam flowmeters cause a permanent pressure
drop and have limited rangeability, wasting time and money.
Since the DigitalFlow GS868’s transducers do not obstruct
the flow, they generally do not cause any pressure drop. The
DigitalFlow GS868 has no parts that foul or collect debris,and no moving parts to wear out. As a result, it requires nolubrication, cleaning or other routine maintenance.

Digital and analog output options
The DigitalFlow GS868 flowmeter makes it easy to send
the data where it needs to go, through the standard digital
output, standard or optional analog outputs, or optional
alarms. All outputs are conveniently set up and calibrated
from the keypad or from a computer using PanaView™
PCinterface software.

Wetted transducers

Fluidflow

Ultrasonic signal path

Transit-time flow measurement technique

Wide range of pipe sizes and flow conditions
With its broad range of measurement velocities and its ability
to measure flow in any pipe from small to very large, one
DigitalFlow GS868 meter does the job of several conventional
meters. It handles pipes from 2 in to 48 in (50 mm to 1200mm) in diameter and velocities from 0.1 to 150 ft/s (0.03 to 46m/s)—in either direction—in saturated or superheated steam.
For maximum accuracy, use a two-channel meter tomeasure along two different paths at the same location.
A two-channel meter can also measure the flow in two
separate pipes for additional cost savings.

Convenient installation
Straightforward installation is another advantage of theDigitalFlow GS868. The flowmeter system consists of one ortwo pairs of transducers, preamplifiers and an electronics
console. The transducers can be installed as part of aflowcell, or installed directly into the existing pipeline. Theelectronics console can be up to 500 ft (150 m) from thetransducers. Local and remote programming and output
options allow the DigitalFlow GS868 to fit in any process.

Steam flow data and diagnostics
In addition to velocity, volumetric and mass flow data, theDigitalFlow GS868 also provides diagnostic parameterssuch as transit times and sound speed, to aid in setup andtroubleshooting. Any of this data can be easily printed,logged, sent to an analog or digital output, or read innumeric or graphic format on the dual window display.

GS868 specifications
Operation and performance
Fluid types
Saturated and superheated steam
Pipe sizes
2 in to 48 in NB (50 mm to 1200 mm DN)
Pipe materials
All metals. Consult Panametrics for other materials.
Flow accuracy (velocity)±1% to 2% of reading typicalAccuracy depends on pipe size and whether measurement
is one-path or two-path. Accuracy to ±0.5% of reading may
be achievable with process calibration.
Repeatability±0.2% to 0.5% of reading
Range (bidirectional)–150 to 150 ft/s (–46 to 46 m/s)
Rangeability (overall)
1500:1
Specifications assume a fully developed flow profile (typically
20 diameters upstream and 10 diameters downstream ofstraight pipe run) and flow velocity greater than 3 ft/s (1 m/s).
Measurement parameters
Mass flow, standard and actual volumetric flow, totalized
flow, and flow velocity

Electronics
Flow measurement
Patented Correlation Transit-Time mode
Enclosures• Standard: Epoxy-coated aluminum weatherproof Type
4X/IP66, FM/CSA Class I, Division 2, Groups A,B,C&D• Optional: Stainless steel, fiberglass, explosion-proof,flameproof, ISSep 03ATEX113
Dimensions
Standard: 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-paths)
Display
Two independent software-configurable 64 x 128 pixel
backlit LCD graphic displays
Keypad39-key tactile-feedback membrane keypad
Power supplies• Standard: 100 to 130 VAC, 50/60 Hz or 200 to 265 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
20 W 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/outputs
Two 0/4 to 20 mA isolated outputs, 550Ω maximum loadNamur NE043 compliant
Optional inputs/outputs
There are six additional slots available for any combination of
the following I/O boards:• Analog outputs: each with four isolated 0/4 to 20 mAoutputs, 1 kΩ maximum load

Transit-time flow measurement technique• Analog input board with two isolated 4 to 20 mA inputs
and 24 V loop power• RTD input board with two isolated, three-wire, RTD inputs;
span –148°F to 662°F (–100°C to 350°C); 100Ω• Totalizer/frequency outputs:- Totalizer mode: Pulse per defined unit of parameter- Frequency mode: Pulse frequency proportional tomagnitude of parameter (e.g., 10 Hz = 1 ft3/h)• Alarm relays:- General purpose- Hermetically sealed

Permanent pressure loss by flowmeter type
4 in (100 mm) vortex shedding
4 in (100 mm) orifice plateTransit-time 		
12 in (300 mm) vortex shedding
12 in (300 mm) orifice plateTransit-time 		

8.28 in H2O 		

Saturated steam flow

14.1 in H2O		

100 ft/s, 4 in Sch 40,

0.05 in H2O		

40 psig (2.7 bar)

186 in H2O 		

Saturated steam flow

0.0 in H2O 		

300°F (148°C)

318 in H2O 		

100 ft/s, 12 in Sch 160,

Digital interfaces

Pressure ranges• Standard: RS232• Standard: 0 to 2700 psig (1 to 187 bar)

• Optional: RS485 (multiuser)• Optional: 3480 psig (240 bar) maximum• Optional: Modbus® RS485 or TCP protocol

Transducer materials• Optional: Ethernet• Standard: Titanium or stainless steel• Optional: OPC serverTransducer mounting
Flanged port: spool piece or cold tap• Optional: Foundation fieldbus
Site parameter programming
Menu-driven operator interface using keypad and “soft”
function keys
Data logging
Memory capacity (linear and/or circular type) to log over
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 EMC Directive 89/336/EEC, 73/23/EEC
LVD (Installation Category II, Pollution Degree 2) andPED 97/23/EC for DN<25

Area classifications• Standard: Weatherproof Type 4/IP65• Optional: Explosion-proof Class I, Division 1, Groups C&D• Optional: Flameproof II 2 G EEx d IIC T6

Additional options
PanaView PC-interface software
The DigitalFlow GS868 communicates with a PC througha serial interface and Windows® operating systems.
Consult the manual for details on sites, logs and otheroperations with a PC.

Wetted ultrasonic flow transducers
Temperature ranges
Overall range –190° to 450°C (–310° to 842°F)

Copyright 2021 Baker Hughes Company. All rights reserved.
BHCS38747(04/2023)

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