Category: Woodward

Applications

SonicFlo™ gas valves provide precise fuel control and shut-off capabilities for large

industrial gas turbines with single or multiple combustion manifold systems. 

The designs feature closely integrated linear valves and actuators which are

based on Woodward’s extensive experience with gas fuel controls.

Robust design and component redundancy result in exceptional service life and system

reliability. The assemblies may be used with electronic controllers

to achieve state-of-the-art control accuracy and response characteristics.

The integral actuator is a single-acting spring-loaded design for failsafe operation.

The actuator includes an on-board hydraulic filter for last-chance filtration of the fluid

to ensure reliability of the servovalve and actuator. The servovalve is electrically

redundant with triple coil design. Position feedback for the actuator is provided by

either a dual or triple coil LVDT (linear variable differential transformer) directly

coupled to the hydraulic piston. Rapid or emergency failsafe operation of the valve

may be initiated by use of the solenoid-operated trip system. The trip system

bypasses the servovalve-modulating control and directs the actuator to its failsafe

position.

The SonicFlo valve controls the flow of gas fuel to the combustion system of an

industrial or utility gas turbine. The unique design yields a flow characteristic

unaffected by discharge pressure up to a pressure ratio (P2/P1) of at least 0.80 for

Standard Recovery and at least 0.91 for High Recovery, reducing the requirement

for additional gas pressure boosting. The design integrates the valve and actuator

into a compact assembly. This close integration allows for lower costs, smaller

envelope and better accuracy.

The integral actuator is a single-acting spring-loaded design for failsafe operation.

The actuator includes an on-board hydraulic filter for last-chance filtration of the fluid

to ensure reliability of the servovalve and actuator. The servovalve is electrically

redundant with triple coil design. Position feedback for the actuator is provided by

either a dual or triple coil LVDT (linear variable differential transformer) directly

coupled to the hydraulic piston. Rapid or emergency failsafe operation of the valve

may be initiated by use of the solenoid-operated trip system. The trip system

bypasses the servovalve-modulating control and directs the actuator to its failsafe

position.

RS-232 Communications Port

An RS-232 communications service port is provided in the J1 harness plug for

connection to a PC service tool. This connection is a typical three-wire RS-232

communication (Tx = J1-A1. Rx = J1-A2. Gnd = J1-A3), which is limited to 15 m

(50 feet). The port supports OPC protocol and has fixed communications settings

of 38.42 K baud rate, 8 data bits, no parity, and 1 stop bit. Refer to Chapter 7 for

details on the Service Tool.

CAN Communications Port

The driver has CAN communications, version 2.0B, with 29-bit identifiers. The

CAN port supports independent positioning (position demand from CAN) and

shutdown of each driver channel. It also supports driver diagnostic monitoring

and position demand feedback. Reading of CAN parameters is available

regardless of the configured Demand Source. The address and data rate

parameters are set using the Service Tool. The data rate may be chosen from

125 kbps, 250 kbps, and 500 kbps.

Shutdown/Reset Discrete Input

When the shutdown contact is opened, the driver goes into a shutdown mode

and the valves are commanded to and held at minimum position. When the

shutdown contact is closed, the driver returns to ‘run’ mode and it resets all driver

faults.

Discrete Output for Driver Status Indication

The discrete output contact is normally on/closed (customer-supplied power

applied to load such as a trip-string relay) under normal driver operation, and

turns off/opens to indicate any detected shutdown condition within the driver.

Both alarm and shutdown indications are latching, which means a reset

command is required to clear the fault. The Service Tool program can be used to

interrogate the cause of the alarm or shutdown. The CAN communications can

also be used to determine alarm and shutdown causes.

The Swift Gas Metering System will continue to operate with an alarm condition

(for example, failure of the primary demand signal). However, the unit will cease

to operate on a shutdown condition (for example, failure of position demand input

signal).

Power Input

The input power has an operational range of 21.5—28 Vdc, nominal 24 Vdc.

Input power out-of-range diagnostics are provided.

Analog Input for Position Demand

The analog inputs are nominally 4–20 mA (25 mA range). Range and failure

diagnostics are provided based on software configuration and settings.

PWM Input for Position Demand

The PWM input accepts a 500 to 2000 Hz input signal of 5 to 26 volts peak-to

peak voltage (referenced to unit battery ground), and each channel is

independently jumper-configurable to accept push-pull or open-collector PWM

signals. The PWM input duty cycle minimum and maximum fields are adjustable

to match the controller sending the demand. Range and failure diagnostics are

provided based on software configuration and settings.

Electrical Connections

Swift Valve

The interface for the Swift is a circular 24-pin sealed connector. All I/O points on

this connector are wired to the Swift Driver. Refer to Chapter 3 for details on

Swift valve wiring.

Swift Driver

The interface for the Swift Driver is a 48-pin PCB-mounted sealed automotive

style receptacle, which protrudes through the driver enclosure. Wiring harness

mating is accomplished using two separate plugs, one 30-pin (J1) and an 18-pin

(J2). Refer to Chapter 3 for details on Swift Driver wiring.

Swift Valve Inputs/Outputs (I/O)

The following Inputs/Outputs (I/O) are available in the Swift Valve:

 driver stepper motor inputs (2)

Driver Stepper Motor Inputs

Each driver channel has stepper motor inputs for connection to the Swift Driver.

Driver Inputs/ Outputs (I/O)

The following Inputs/Outputs (I/O) are available in the Swift Driver:

  power input

 2 analog inputs; one per valve channel (optional)

 2 PWM inputs; one per valve channel (optional)

 1 discrete input

 1 discrete output

 1 RS-232 communications port

 1 CAN (Controller Area Network)/DeviceNet port

Swift Valve

The Swift valve is a sonic flow-metering valve. The valve has a

converging/diverging nozzle and a moving needle to adjust the valve flow area.

An open loop step motor through a rack and pinion drive positions the needle. A

return spring is included to remove the effects of gear backlash and to minimize

closed-valve leakage. A mechanical stop allows the valve to re-zero the valve

position during start-up. After the re-zero, the driver counts the step motor steps

and monitors the step motor position.

Swift Driver

The driver is effectively a positioner that will accept a desired position signal from

another device in the system, such as a speed control, and drive the valve to that

position. The position controller software is executed on dual Texas Instruments

16-bit DSPs, operating at 40 MHz, onboard the Swift Driver. The driver can be

commanded to a position via 4–20 mA, PWM, or CAN/DeviceNet interfaces. The

driver monitors all available signals, internal and external, and annunciates any

detected shutdown conditions through the discrete output. A discrete input is

available to remotely shut down the actuator and to reset shutdown conditions.

Features of the driver include dual (2) model-based position control loops, on-line

diagnostics, CAN communications, and service port communications (described

in detail in Chapter 5). A Windows-based Service Tool software program is

available for monitoring, troubleshooting, and parameter adjustments. The

Service Tool software is loaded on a PC and communicates serially to the driver

via RS-232. Refer to Chapter 7 (Service Tool) for installation instructions.

Description

The system is available in two primary configurations. The “Swift” configuration

provides either single- or dual-metering valves in a single housing. This

configuration can be integrated into a new or existing gas metering system to

provide low-cost, accurate, reliable control. The Swift Model 200 system, sizes

65. 36. and 20. have been designed to provide system mass flow accuracy of 2%

of point at 100% of rated flow across the entire temperature range. The Swift

Model 200 system, size 11. has been designed to provide system mass flow

accuracy of 6.2% of point between 50 and 100% of rated flow, across the entire

temperature range.

The Swift gas metering system components include one or two metering valves

and one valve driver (see Figure 1-1). For fuel systems requiring two

independently modulated fuel flows, the primary valve can be integrated with a

secondary metering valve. The primary valve can accommodate this integration

without duplicating either electrical or mechanical connections.

Description

The system is available in two primary configurations. The “Swift” configuration

provides either single- or dual-metering valves in a single housing. This

configuration can be integrated into a new or existing gas metering system to

provide low-cost, accurate, reliable control. The Swift Model 200 system, sizes

65. 36. and 20. have been designed to provide system mass flow accuracy of 2%

of point at 100% of rated flow across the entire temperature range. The Swift

Model 200 system, size 11. has been designed to provide system mass flow

accuracy of 6.2% of point between 50 and 100% of rated flow, across the entire

temperature range.

The Swift gas metering system components include one or two metering valves

and one valve driver (see Figure 1-1). For fuel systems requiring two

independently modulated fuel flows, the primary valve can be integrated with a

secondary metering valve. The primary valve can accommodate this integration

without duplicating either electrical or mechanical connections.

Introduction

This manual describes the Woodward Swift™ Gas Metering System for

micro/mini-turbines, small industrial turbines, and high-pressure fuel cell

applications. This manual provides installation instructions, product description,

troubleshooting, and specifications. This manual does not contain instructions for

the operation of the complete prime mover system. For prime mover or plant

operating instructions, contact the plant-equipment manufacturer.

Applications

The Woodward Swift gas metering system operates on micro/mini-turbines, and

small industrial turbines ranging from 30 to 2000 kW, as well as high-pressure

fuel cells (> 97 kPa/14 psig) up to 3000 kW. The Swift system has four valve

sizes with maximum fuel flows of 6 to 88 g/s (50 to 695 lb/hr) of standard natural

gas, depending on the system pressures (see Table 1-1). The system is

designed for installation in the prime mover enclosure and can accommodate gas

temperatures up to 121 °C (250 °F).