Fire extinction design for an auxiliary power unit compartment of an aircraft

Patent metadata

Field	Value
Publication number	US-10202201-B2
Application number	US-201514951576-A
Country	US
Kind code	B2
Filing date	Nov 25, 2015
Priority date	Nov 27, 2014
Publication date	Feb 12, 2019
Grant date	Feb 12, 2019

Abstract

The invention refers to an APU compartment, and a method for extinguishing a fire in an APU compartment. The APU compartment ( 1 ) comprises an APU ( 2 ), an exhaust ( 5 ), an aperture ( 7 ) providing a passage between the APU compartment ( 1 ) and the inside of the exhaust ( 5 ), and a fire detection system, wherein the APU compartment ( 1 ) of the invention is constructed as an air tight compartment, and additionally comprises a conduit ( 9 ) for providing external air to the APU compartment ( 1 ), a door ( 8 ) for closing the conduit ( 9 ) inlet, and a control unit ( 6 ) configured to close the door ( 8 ) when a fire is detected, such that when the door ( 8 ) is closed and the APU ( 2 ) is in operation, the air contained in the APU compartment ( 1 ) is sucked through the aperture ( 7 ) to be expelled out of the APU compartment ( 1 ) to extinguish the fire.

First claim

What is claimed:

1. An auxiliary power unit compartment ( 1 ) of an aircraft, comprising:
an auxiliary power unit ( 2 ) placed in the auxiliary power unit compartment ( 1 ) and having a turbine ( 3 );
an intake duct ( 4 ) having an intake door ( 10 ), the intake duct ( 4 ) for providing external air only to the turbine ( 3 ) and not to the auxiliary power unit compartment ( 1 );
an exhaust ( 5 ) for expelling combustion gases;
an aperture ( 7 ) providing a passage between the auxiliary power unit compartment ( 1 ) and an inside of the exhaust ( 5 ), and
a temperature dependent fire detection system associated with the auxiliary power unit compartment ( 1 ) for detecting a fire within the auxiliary power unit compartment ( 1 ),
wherein the auxiliary power unit compartment ( 1 ) is constructed as an air tight compartment and includes a conduit ( 9 ) for providing external air only to the portion of the space inside the auxiliary power unit compartment ( 1 ) that is outside of the auxiliary power unit ( 2 ), a door ( 8 ) for closing the conduit ( 9 ) inlet, and a control unit ( 6 ) being configured to independently close and open both the intake door ( 10 ) and the door to conduit ( 9 ) and also configured to close the door ( 8 ) while maintaining the intake door ( 10 ) open when a fire is detected by the fire detection system, such that when the door ( 8 ) is closed and while the auxiliary power unit ( 2 ) is in operation, the air contained in the auxiliary power unit compartment ( 1 ) is pulled out through the aperture ( 7 ) and expelled out of the auxiliary power unit compartment ( 1 ) through the exhaust ( 5 ) to thereby extinguish the fire.

2. The auxiliary power unit compartment ( 1 ) of claim 1 , wherein the control unit ( 6 ) is operable to shut off the auxiliary power unit ( 2 ) once the fire is extinguished.

3. The auxiliary power unit compartment ( 1 ) of claim 1 , wherein the control unit ( 6 ) is operable to close the intake door ( 10 ) when the auxiliary power unit ( 2 ) is shut off.

4. The auxiliary power unit compartment ( 1 ) of claim 1 , wherein the conduit ( 9 ) is formed as a part of the intake duct ( 4 ).

5. The auxiliary power unit compartment ( 1 ) of claim 1 , wherein the auxiliary power unit ( 2 ) has an oil cooler ( 11 ), and wherein said oil cooler ( 11 ) comprises the aperture ( 7 ).

6. The auxiliary power unit compartment ( 1 ) of claim 1 , wherein the door ( 8 ) is provided at a fuselage ( 12 ) of the rear end of an aircraft.

7. The auxiliary power unit compartment ( 1 ) of claim 1 , wherein the intake duct ( 4 ) is provided at a fuselage ( 12 ) of the rear end of an aircraft.

8. A method for extinguishing a fire in an auxiliary power unit compartment ( 1 ) of an aircraft, the method comprising the steps of:
providing an auxiliary power unit ( 2 ) located in the auxiliary power unit compartment ( 1 );
detecting a fire within the auxiliary power unit compartment ( 1 ) based on a temperature change within the compartment ( 1 );
providing the auxiliary power unit compartment ( 1 ) as an air tight compartment;
providing a conduit ( 9 ) having a door ( 8 ) for introducing external air only into the auxiliary power unit compartment ( 1 ) and a separate intake duct ( 4 ) having an intake door ( 10 ) for providing external air only to the auxiliary power unit;
closing the door ( 8 ) to the conduit ( 9 ) to prevent the entrance of external air into the auxiliary power unit compartment ( 1 ) when a fire is detected while maintaining the intake door ( 10 ) in an open position to provide external air to the auxiliary power unit, and
when a fire is detected inside the auxiliary power unit compartment ( 1 ) maintaining the auxiliary power unit in an on condition thereby pulling the air contained inside the auxiliary power unit compartment ( 1 ) out through an aperture ( 7 ) of the auxiliary power unit ( 2 ), the aperture ( 7 ) providing a passage between the auxiliary power unit compartment ( 1 ) and an exhaust ( 5 ) of the auxiliary power unit ( 2 ), the pulling of air lasting for a period of time until a pressure differential between the inside of the exhaust ( 5 ) and the auxiliary power unit compartment ( 1 ) is compensated, thereby removing the air contained in the auxiliary power unit compartment ( 1 ) and also extinguishing the fire.

9. The method for extinguishing a fire of claim 8 , further comprising:
shutting off the auxiliary power unit ( 2 ) once the fire is extinguished.

10. The method for extinguishing a fire of claim 9 , further comprising:
closing the intake door ( 10 ) to prevent the entrance of external air through the intake duct into the auxiliary power unit ( 2 ) once the fire is extinguished.

Assignees

• Airbus Operations Sl

Inventors

• Mora Angel Palomares

Classifications

• B64D2033/0213

  specially adapted for auxiliary power units (APU's) · CPC title

• F01D5/02

  Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28}) · CPC title

• B64D2045/009

  Fire detection or protection; Erosion protection, e.g. from airborne particles · CPC title

• B64D41/00 Primary

  Power installations for auxiliary purposes · CPC title

• F05D2240/24

  for turbines · CPC title