Woodward LQ6 Liquid Fuel Valve with On‐board Driver

Applications

The LQ6 provides the flow range, accuracy, and response characteristics

necessary for the control of industrial gas turbines in the 3 MW to 15 MW

power range. By integrating Woodward’sproprietary electric actuation technology

with a proven fuel-metering concept, exceptional performance androbustness

are achieved in a compact, cost effective package. The use of on board driver

electronics simplifies system design and reduces installation space, time, and cost.

Please refer to Woodward Installation and Operation Manual 26515 for complete

details of this product, its application and installation.

Description

The LQ6 incorporates an electrically actuated rotary metering valve, a bypassing

regulator, and an on-board driver module. These components are packaged within a

common assembly to reduce cost and improve performance.

Highly accurate flow control is achieved by the use of a rotary plate element,

embodying a precision-machined metering port. A seal shoe is loaded against the

plate to achieve accurate flow area control over a wide range. The self-cleaning,

shear-type action keeps the metering port free from contaminant deposits and

system debris.

The metering section utilizes a single moving part with the valve plate, actuator rotor,

and position feedback resolver mounted on a single shaft. Accurate flow versus input

signal characteristics are achieved by the precision machining of the valve metering

port, the use of large valve travels, and a high-precision resolver for valve position

feedback. The LQ valve can achieve flow turn-down ratios in excess of 100 to 1.

The pressure differential across the metering valve port is held virtually constant by a

bypassing-type regulator. When this pressure difference exceeds the selected level,

the regulator piston progressively opens to bypass excess inlet flow back to the fuel

pump inlet area. This pressure regulation system requires the use of a positive

displacement, high-pressure fuel pump upstream of the LQ6 valve.

The use of rare-earth permanent magnets in an efficient electromagnetic circuit

results in high actuation forces while minimizing package size. The closely integrated

mechanical design eliminates backlash and provides virtually infinite valve

positioning resolution.