This application claims priority to United Kingdom Patent Application No. GB 1518359.3 filed 16 Oct. 2015, the entire contents of which is incorporated herein by reference.
The present disclosure relates to fire suppression systems and in particular to fire suppression systems for aircraft.
Aircraft are typically provided with fire suppression systems, for example for providing fire suppression in cargo or other compartments of the aircraft. Most of these systems use Halon 1301 as a suppression agent. However, Halon 1301 destroys the ozone layer and is therefore being phased out of use. For example, the European Union now requires the introduction of environmentally friendly suppression agents in new aircraft from 2019 onwards. All aircraft will have to be Halon-free by 2040. The Federal Aviation Authority and the aircraft industry have selected and tested a number of Halon replacement agents.
Most of these alternative agents require a higher mass flow or volumes to be distributed in the protected enclosure. This may require that the suppression agent be stored at relatively high pressures. This in turn may require a flow control device such as a pressure regulation device and a pressure relief valve to be incorporated in the suppressant distribution system. Such an arrangement is disclosed, for example, in U.S. Pat. No. 8,678,101.
It has been recognised by the Applicant, however, that potential problems may arise in the practical implementation of such a system. This disclosure aims to address or mitigate such problems.
From one aspect, the present disclosure provides a fire suppression system for an aircraft compartment, the system comprising a source of fire suppression agent; a supply line for conducting the fire suppression agent to the compartment; the supply line comprising a flow control device arranged between the source and the compartment and a pressure relief valve arranged downstream of the flow control device; the pressure relief valve having an outlet which distributes the agent externally of the compartment.
In an embodiment, the pressure relief valve discharges into a region of the aircraft between the compartment and the aircraft fuselage, for example into a bilge or cheek compartment.
The agent may be distributed along a length of the aircraft fuselage and/or circumferentially around the fuselage.
The outlet of the pressure relief valve may be of any construction which distributes the suppression agent.
In one embodiment, the outlet may comprise a plurality of discrete outlets.
In another embodiment, the outlet may comprise a perforated member such as a perforated tube or pipe.
In another embodiment, the outlet may comprise an elongate outlet such as a slot.
In another embodiment, the outlet may comprise a porous element, such as mesh element.
In another embodiment, the outlet may comprise a fabric element, for example a fire resistant fabric.
The fabric may be formed into a bag which is inflatable by the agent and through the wall of which the agent diffuses.
The disclosure also extends to a method of adapting a fire suppression system for an aircraft compartment comprising a source of fire suppression agent; a flow path for conducting the fire suppression agent to the compartment; the flow path comprising a flow control device arranged between the source and the compartment and a pressure relief valve arranged downstream of the flow control device, the method comprising providing the pressure relief valve with an outlet which distributes the agent externally of the compartment.
From a further aspect, the disclosure provides a method of providing fire protection for an aircraft compartment, comprising the step of venting fire suppression agent from an agent supply line through a pressure relief valve which discharges the agent in a distributed manner externally of the compartment.
Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:
With reference to the Figures, an aircraft 2 comprises a fuselage 4 which includes an upper passenger compartment 6 and a lower cargo compartment 8 separated from the passenger compartment by a floor 9. The cargo compartment 8 is arranged within a lower space 10 of the fuselage 2. The lower space 10 has a bilge area 12 below the cargo compartment 8 and cheek areas 14 to the sides of the cargo compartment 8.
The cargo compartment 8 is provided with a fire suppression system 16. The fire suppression system 16 comprises a pressurised source 18 of a fire suppression agent such as argon, nitrogen, helium, carbon dioxide, heptafluoropropane or mixtures thereof. An agent supply line 20 leads to a low pressure distribution network 22 having, for example, one or more agent outlets 24 within the compartment 8.
A flow control device 26, for example a pressure regulating device is arranged in the supply line 20 between the high pressure agent source 18 and low pressure distribution network 22. The flow control device 26 reduces the flow of fire suppression agent from the agent source 18 to prevent an excessive pressure build-up within the compartment 8. The flow control device 26 can be of any suitable construction and may comprise a regulation device or a simple flow limiting device such as a flow limiting orifice.
In addition to the flow control device 26, a safety pressure relief valve 28 is fluidly connected to the supply line downstream of the flow control device 26 and in fluid communication with the low pressure distribution network 22. The pressure relief valve is configured to open above a pre-set pressure to relieve excessive pressure in the distribution network 22 to prevent damage to the cargo compartment 8. It may further be configured to close again once the pressure has returned to a safe value.
The pressure relief valve 28 has an outlet 30. The outlet 30 is arranged in the lower space 10 between the cargo compartment 8 and the fuselage 4. As illustrated in
The outlet 30 distributes the vented agent within the space 10 in such a manner as to avoid a localised high pressure which could damage the area, for example to a compartment liner or fuselage insulation. The agent may be distributed along a length of the fuselage 4 and/or circumferentially around the fuselage 4.
The outlet 30 may be designed in any manner to produce a distributed discharge. The outlet 30 may therefore have a plurality of discrete outlet ports 32, for example nozzles as illustrated.
In other embodiments, however, the outlet 30 may comprise a perforated member such as a perforated tube or pipe. In another embodiment, the outlet may comprise an elongate outlet such as a slot. In another embodiment, the outlet may comprise a porous element, for example a mesh element. In another embodiment, the outlet may comprise a porous fabric element, for example a fire resistant fabric. The fabric may be formed into an inflatable bag which inflates with agent and through which the agent may then diffuse.
It will be understood that the disclosure in its embodiments may provide the advantage of allowing a non Halon fire suppression agent which is stored at a higher pressure than Halon, to be used on an aircraft without potentially damaging the aircraft in the event of an excessive pressure, for example in the event of the failure of the flow control device 26.
Whilst disclosed in the context of protecting an aircraft cargo compartment, the disclosure also extends to protection of other compartments and enclosures within the aircraft fuselage 4. For example, the compartment may an electronics, avionics or auxiliary Power Unit (APU) compartment. The compartment may be in any part of the fuselage, as long as there is a space between the compartment and the fuselage into which the fire suppression agent may be vented in a distributed manner.
Number | Date | Country | Kind |
---|---|---|---|
1518359 | Oct 2015 | GB | national |
Number | Name | Date | Kind |
---|---|---|---|
1974828 | Markut | Sep 1934 | A |
2424764 | Marshall, Jr. | Jul 1947 | A |
3788666 | Kramer | Jan 1974 | A |
3893514 | Carhart | Jul 1975 | A |
3940549 | Whittum | Feb 1976 | A |
4432514 | Brandon | Feb 1984 | A |
5211246 | Miller | May 1993 | A |
5501284 | Clodfelter | Mar 1996 | A |
5660236 | Sears | Aug 1997 | A |
6676081 | Grabow et al. | Jan 2004 | B2 |
6860331 | Hagen | Mar 2005 | B2 |
8678101 | Gatsonides et al. | Mar 2014 | B2 |
8813858 | Gatsonides et al. | Aug 2014 | B2 |
20070079974 | Thompson | Apr 2007 | A1 |
20070125286 | Lothe | Jun 2007 | A1 |
20100089597 | Neeb | Apr 2010 | A1 |
20100170684 | Richardson | Jul 2010 | A1 |
20100187358 | Voss | Jul 2010 | A1 |
20100236796 | Chattaway | Sep 2010 | A1 |
20110048747 | Gastonides | Mar 2011 | A1 |
20110315406 | Connery | Dec 2011 | A1 |
20140110137 | Ribarov | Apr 2014 | A1 |
20150184756 | Palmqvist | Jul 2015 | A1 |
Number | Date | Country |
---|---|---|
2724753 | Apr 2014 | EP |
2813266 | Dec 2014 | EP |
2015119683 | Aug 2015 | WO |
Entry |
---|
Distributed. Collins English Dictionary—Complete and Unabridged, 12th Edition 2014. (1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014). Retrieved Oct. 10, 2019 from https://www.thefreedictionary.com/distributed (Year: 2014). |
Circumferentially, https://www.dictionary.com/browse/circumferential (2020). Retrieved Oct. 9, 2020 (Year: 2020). |
Spatial, https://www.merriam-webster.com/dictionary/spatial#:˜:text=1%20%3A%20relating%20to%2C%20occupying%2C,of% 20spatial%20ability%20spatial%20memory (Year: 2020). |
GB Search Report for Application No. GB1518359.3. dated Apr. 18, 2016. 3 Pages. |
European Search Report for Application No. 16192417.0-1659 dated Feb. 27, 2017, 7 pages. |
Number | Date | Country | |
---|---|---|---|
20170106221 A1 | Apr 2017 | US |