GE DigitalFlow GS868 Product Overview And Specifications

Applications

The DigitalFlow GS868 steam ultrasonic fl owmeter
is a complete ultrasonic fl ow metering system that
measures saturated or superheated steam for:

• Heating, ventilating and air conditioning (HVAC)

• Pneumatic power systems

• Food and beverage industry

• Water purifi cation and distillation

• Chemical and petrochemical industries

• Electric power generation

• Steel industry

• Public works

• Manufacturing

Features

• Bidirectional

• No moving parts

• No pressure drop

• Wide rangeability with 1500 to 1 turndown ratio

• Non-obstructive fl ow measurement

• Tolerance to dirty streams

• Low maintenance

• Suitable for high temperatures

• Two-path measurement available for maximum
accuracy

GE

Sensing & Inspection Technologies

DigitalFlow

™

GS868

Panametrics Ultrasonic Steam
Mass Flowmeter

GE imagination at work

Panametrics Ultrasonic Steam Mass
Flowmeter

The DigitalFlow GS868 steam ultrasonic fl owmeter is
designed to measure the mass fl ow rate of saturated or
superheated steam. It off ers a unique combination of
no pressure drop, wide rangeability, ease of installation,
low maintenance and high accuracy in a full-feature
fl owmeter package.

The DigitalFlow GS868 Flowmeter
Uses the Correlation Transit-Time

™

Technique

Compact ultrasonic transducers are installed in the pipe
or duct, one upstream of the other. The transducers send
and receive ultrasonic pulses through the steam. The
meter measures the diff erence between the upstream
and downstream transit times, and uses digital signal
processing, advanced signal processing and correlation
detection to calculate velocity and volumetric fl ow rate.
Mass fl ow is calculated from the input of temperature
and pressure and the built-in steam tables.

No Pressure Drop, Low Maintenance

In 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 fl owmeters cause a permanent
pressure drop and have limited rangeability, wasting time
and money. Since the DigitalFlow GS868’s transducers
do not obstruct the fl ow, 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 no lubrication, cleaning or other
routine maintenance.

Digital and Analog Output Options

The DigitalFlow GS868 fl owmeter 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

™

PC-interface software.

Wide Range of Pipe Sizes and Flow
Conditions

With its broad range of measurement velocities and its
ability to measure fl ow 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 1200 mm) in diameter and velocities
from 0.1 to 150 ft/s (0.03 to 46 m/s)―in either direction―in
saturated or superheated steam.

For maximum accuracy, use a two-channel meter to
measure along two diff erent paths at the same location.

A two-channel meter can also measure the fl ow in two
separate pipes for additional cost savings.

Convenient Installation

Straightforward installation is another advantage of the
DigitalFlow GS868. The fl owmeter system consists of
one or two pairs of transducers, preamplifi ers and an
electronics console. The transducers can be installed as
part of a fl owcell, or installed directly into the existing
pipeline. The electronics console can be up to 500 ft (150
m) from the transducers. Local and remote programming
and output options allow the DigitalFlow GS868 to fi t in
any process.

Steam Flow Data and Diagnostics

In addition to velocity, volumetric and mass fl ow data, the
DigitalFlow GS868 also provides diagnostic parameters
such as transit times and sound speed, to aid in set­up and troubleshooting. Any of this data can be easily
printed, logged, sent to an analog or digital output, or
read in numeric or graphic format on the dual window
display.

Transit-time fl ow measurement technique

Wetted transducers

Fluid
fl ow

Ultrasonic signal path

GS868 Specifi cations

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 GE for other materials.

Flow Accuracy (Velocity)

±1% to 2% of reading typical

Accuracy 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

Specifi cations assume a fully developed fl ow profi le
(typically 20 diameters upstream and 10 diameters
downstream of straight pipe run) and fl ow velocity greater
than 3 ft/s (1 m/s).

Measurement Parameters

Mass fl ow, standard and actual volumetric fl ow, totalized
fl ow, and fl ow 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, fi berglass, explosion-proof,
fl ameproof, 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-confi gurable 64 x 128 pixel
backlit LCD graphic displays

Keypad

39-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%

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 load

Transit-time fl ow measurement technique

© 2009 General Electric Company. All Rights Reserved. Specifi cations are subject to change without notice. GE is a registered trademark of General Electric Company. Other company or product
names mentioned in this document may be trademarks or registered trademarks of their respective companies, which are not affi liated with GE.

www.gesensinginspection.com

920-006D

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 mA
outputs, 1 kΩ maximum load

• 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 defi ned unit of parameter
– Frequency mode: Pulse frequency proportional to
magnitude of parameter (e.g., 10 Hz = 1 ft

3

/h)

• Alarm relays:

– General purpose
– Hermetically sealed

Permanent pressure loss by fl owmeter type

4 in (100 mm) vortex shedding 8.28 in H2O Saturated steam fl ow
4 in (100 mm) orifi ce plate 14.1 in H2O 100 ft/s, 4 in Sch 40,
Transit-time 0.05 in H2O 40 psig (2.7 bar)

12 in (300 mm) vortex shedding 186 in H2O Saturated steam fl ow
12 in (300 mm) orifi ce plate 318 in H2O 100 ft/s, 12 in Sch 160,
Transit-time 0.0 in H2O 300°F (148°C)

Digital Interfaces

• Standard: RS232

• Optional: RS485 (multiuser)

• Optional: Modbus® RS485 or TCP protocol

• Optional: Ethernet

• Optional: OPC server

• Optional: Foundation fi eldbus

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 fl ow data points

Display Functions

• Graphic display shows fl ow 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) and PED
97/23/EC for DN<25
Wetted Ultrasonic Flow Transducers
Temperature Ranges
Overall range –190° to 450°C (–310° to 842°F)

Pressure Ranges

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

• Optional: 3480 psig (240 bar) maximum

Transducer Materials

• Standard: Titanium or stainless steel

Transducer Mounting

Flanged port: spool piece or cold tap

Area Classifi cations

• 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 through
a serial interface and Windows® operating systems.
Consult the manual for details on sites, logs and other
operations with a PC.

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