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Fuel Flow

Gas fuel flow is normally achieved by the accurate scheduling of the metering valve port area, based on

values for gas properties, operating pressures, and temperature. The GS-Series valve is factory calibrated

under flow and pressure conditions to provide an accurate valve metering to the input demand signal.

Flow equations for the valves are located in the O&M manual. These can be used to set up the valve for

any site-specific conditions.

Port Sizes

The GS-Series is available with five different port sizes to optimize valve performance for various flow and

pressure drop requirements. Standard port effective area sizes are:

GS40

• 0.30 in² (193.5 mm²)

• 0.75 in² (483.9 mm²)

GS50

• 1.0 in² (645.2 mm²)

• 1.5 in² (967.7 mm²)

• 2.0 in² (1290.3 mm²)

The standard metering ports are contoured to provide approximately square law relationships between

commanded position and effective area.

The on-board valve driver performs the following functions:

• Fast and accurate closed loop position control of the gas valve in response to the 4–20 mA or

CANopen/RT

Ethernet input command signal

• Actual valve position feedback via 4–20 mA or CANopen/RT Ethernet

• Independent remote shutdown input

• Valve/driver fault output

The driver includes protection and alarm indications for the following faults:

• Analog input out of range

• Feedback—open wire and short

• Input power out of range

• Position error

• Internal driver faults

• Actuator open/short

• Driver overcurrent

All faults are available through the CANopen/RT Ethernet connection or through an Ethernet Service

connection.

On-board Driver

The valve driver and wiring terminal box are integral with the valve assembly,

eliminating interconnecting wiring, reducing package size requirements, and

lowering the installed cost. The on-board driver can be interfaced to the turbine

control via redundant 4–20 mA input and feedback signals, through redundant

CANopen control networks, or through redundant real-time Ethernet networks. The

GS-Series can be configured to accept both the 4–20 mA signal and CANopen/RT

Ethernet position command in a redundant configuration. With this arrangement, if

either demand signal fails, the driver will switch to the healthy input demand signal.

The valve driver operates with a 90-150 VDC or 18-32 VDC power supply,

depending on the model.

Description

The GS-Series is an electrically actuated fuel valve with an on-board electronic

driver. The self-cleaning, shear-type metering action keeps the metering port free

from performance-limiting deposits of gas condensates, contaminants, and system

debris. The valve minimizes the moving parts within the fuel metering element,

actuator rotor, and redundant position feedback resolvers to maximize accuracy over

the entire operating range. Available actuator torque has been increased to provide

more robust performance in the harshest conditions. Accurate flow versus input

signal characteristics is achieved on each valve version by precision forming of the

valve metering port, the use of extended valve travels, and high precision resolvers

for valve position feedback. The GS valves can achieve flow turn-down ratios in

excess of 100 to 1. The positive flow shut-off rating meets the requirements of ANSI

B16.104 Class IV across all valve sizes and ports.

• Electric actuation

• Integrated driver

• Robust self cleaning valve

• Aluminum or stainless steel body

• Multiple trim sizes available

• -40°F to 350°F fuel range

• Fuel pressures to 1440 psig

• SAE and ANSI RF flange options

• 24 VDC or 125 VDC input voltage options

• IIoT ready

• Analog and digital I/O

• Models available with CE Marking to applicable directives, with IECEx

Certification to Hazardous Locations, and North America

• 100% Hydrogen Compatible Model Available

Applications

The Woodward GS Series gas fuel metering valve

family is the latest version of rotary control valves

utilizing an integrated actuator and on-board driver

built on decades of application experience in the

gas turbine market.

The self-cleaning valve design is ideal for applications ranging from clean pipeline

gas to wellhead gas. The valve features an on-board electric actuator driver for

ease of packaging and installation. The on-board driver eliminates the need for

costly climate-controlled terminal boxes and associated cabling. Each valve

includes redundant position feedback resolvers and an integral failsafe spring to

maximize reliability and safety. The integrated driver incorporates redundant signal

conditioning, fault detection, and selectable failure management options. The

multiple valve sizes and trims can be configured in single or multi-path systems to

enable a wide range of applications.