Avco Corporation

Richard M Norris

Kimball J Rumford

Douglass S Youd

Joseph P Murphy

Alan John Charlton

Peter Kent

Bert A Diehl, Jr

A unique anti-icing management system for a gas turbine engine is disclosed according to which, at all times, only the required amount of heat is applied to inlet surfaces of the engine to prevent the formation of ice. Heated air is bled from the compressor discharge for this purpose and the amount of flow of the heated air is adjusted by a uniquely operated solenoid valve under the direction of an electronic control responsive to any one of a variety of meaningful conditions including, but not necessarily limited to, temperature of an anti-iced surface at the inlet to the engine, rotational speed of the engine, and the presence of an ice producing meteorological condition. The solenoid valve assumes only two operable positions, namely, a fully open position and a fully closed position, and is operated in a pulsed fashion to control flow on a time basis, rather than on a percentage-of-opening basis which is the conventional mode of operation. A switching operation or mechanism within the electronic control, such as a microprocessor, is responsive to any of the aforementioned conditions to cause the solenoid valve to pulsate according to a predetermined pattern which assures a minimally sufficient flow rate of heated air to the regions to be heated.

Method of operating anti-icing valve

Anti-icing valve

An anti-icing management system for a gas turbine engine according to which, at all times, only the required amount of heat is applied to inlet surfaces of the engine to prevent the formation of ice. Heated air is bled from the compressor discharge, or from some other suitable heat source, for this purpose. The amount of flow of the heated air is adjusted by an electronic control responsive to the temperature of the anti-iced engine inlet surfaces directly in the path of incoming air. The electronic control may be effective to admit flow of the heated air to the region to be heated when a separate ice detector determines the presence of ice and so informs the control.

Anti-icing management system

A modular multi-channel particle separator is provided to block foreign objects from entering the inlet of a gas turbine engine and to remove particulate matter from the inlet air stream before it reaches the compressor section of the engine. Each module is designed for easy fabrication from sheet material which can be readily configured to remove both fine and coarse particles from the air stream with minimal pressure loss, system volume and weight. Each module also defines passages for removing particular matter that has been intercepted and for conducting heating air through the module to prevent icing. The modular construction of the separator simplifies initial assembly in the gas turbine engine, as well as later maintenance and replacement of one or more modules, should that prove necessary.

Modular multi-channel particle separator

The inlet and primary impingement surfaces of a particle separator used in a gas turbine engine are coated with a composition consisting substantially of cellulose nitrate.

Apparatus for improving particle separator efficiency

A multichannel particle separator for use in cleaning engine inlet air is disclosed. The separator uses a plurality of channel assemblies arranged in parallel side-by-side fashion within a substantially rectangular housing. Separation of undesired particles is achieved by accelerating the incoming airstream to a high velocity and turning it such that inertia carries the dirt particles into a particle collection chamber. A small percentage of the incoming air is used to induce particulate matter to proceed into the particle collection chambers. Heated air from a source within the adjacent engine is passed along passages within the interior of each channel assembly to heat the surface thereof and prevent ice formation thereon when operating under adverse meteorological conditions. The small percentage of diverted incoming air and the spent hot air are combined in the particle collection chambers to form a turbulence generator which maintains the separated particulates and collected moisture in suspension for exhaustion overboard through a common scavenge manifold.

Multichannel particle separator of the anti-icing type

In a gas turbine engine, a duct is constructed extending axially and communicating directly, through a transverse opening, with the engine plenum. The plenum extends upward into the engine nacelle and connects with the inlet to the compressor of the gas turbine engine. A portion of the air entering the duct is drawn into the plenum. The remainder is exhausted out of the rear portion of the duct. To create inertial separation, a door is mounted on a lever arm which may be rotated between two positions. In one position the door partially closes the entrance to the plenum causing the airflow to turn through a greater angle in order to enter the plenum. The turning motion of the airflow divides the particles of heavier mass to the outside of the turn. These particles will be exhausted from the rearward exit of the duct. In a second position the door closes the rear portion of the duct so that the entire volume of air entering the duct is supplied to the engine plenum.

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Stratford, CT, United States of America

Richard M Norris