U.S. patent application number 14/830173 was filed with the patent office on 2017-02-23 for fire detection and suppression pack for battery-powered personal computing devices.
This patent application is currently assigned to THE BOEING COMPANY. The applicant listed for this patent is THE BOEING COMPANY. Invention is credited to David W. Kirkbride.
Application Number | 20170050062 14/830173 |
Document ID | / |
Family ID | 58156876 |
Filed Date | 2017-02-23 |
United States Patent
Application |
20170050062 |
Kind Code |
A1 |
Kirkbride; David W. |
February 23, 2017 |
FIRE DETECTION AND SUPPRESSION PACK FOR BATTERY-POWERED PERSONAL
COMPUTING DEVICES
Abstract
Systems and methods for mitigating the risk of and/or
suppressing fires caused by lithium battery-powered personal
computing devices used on the flight deck or in crew and passenger
compartments onboard an aircraft. A fire detection and suppression
pack is attached to a lithium-ion battery-powered portable personal
computing device. The fire detection and suppression pack has a
weight and volume consistent with and does not impair the use of
the portable personal computing device. The fire detection and
suppression pack is a full-time fire suppression system that is on
hot standby at all times, independent of the computing device's
power mode. The fire detection and suppression pack uses gases
stored in canisters to provide cool-down, displacement suppressant
to control and extinguish any fire source and associated burnable
fuel required to sustain the fire event.
Inventors: |
Kirkbride; David W.; (Allyn,
WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE BOEING COMPANY |
Chicago |
IL |
US |
|
|
Assignee: |
THE BOEING COMPANY
Chicago
IL
|
Family ID: |
58156876 |
Appl. No.: |
14/830173 |
Filed: |
August 19, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 60/122 20130101;
A62C 3/08 20130101; H01M 10/0525 20130101; H01M 2200/10 20130101;
A62C 37/36 20130101; A62C 3/00 20130101; A62C 3/16 20130101; A62C
13/76 20130101; A62C 13/62 20130101; H01M 10/486 20130101; A62C
99/0018 20130101; H01M 2220/30 20130101 |
International
Class: |
A62C 3/00 20060101
A62C003/00; H01M 10/0525 20060101 H01M010/0525; H01M 10/48 20060101
H01M010/48; A62C 13/62 20060101 A62C013/62; A62C 13/76 20060101
A62C013/76 |
Claims
1. A fire detection and suppression pack comprising: an open
box-like dock case secured to a keyboard half of a battery-powered
personal computing device and configured to support said keyboard
half seated thereon with an interface volume therebetween such that
said keyboard half is accessible to a user when a display half of
said battery-powered personal computing device is raised and
separated from said keyboard half; a source of suppressant; a
suppressant regulation and distribution system connected to said
source of suppressant; and a control processor configured to issue
an activation signal to said suppressant regulation and
distribution system when a signal is received indicating that a
temperature inside or outside the battery-powered personal
computing device equals or exceeds a first limit set to indicate a
fire event, wherein said suppressant regulation and distribution
system is configured to discharge and direct a flow of suppressant
from said source of suppressant to said interface volume between
the battery-powered personal computing device and the fire
detection and suppression pack in response to receipt of said
activation signal.
2. The fire detection and suppression pack as recited in claim 1,
wherein said suppressant regulation and distribution system
comprises a suppressant flow control module that is configured to
discharge suppressant from said source of suppressant in response
to receipt of said activation signal.
3. The fire detection and suppression pack as recited in claim 2,
wherein said suppressant regulation and distribution system further
comprises: an expansion bladder having a port and a plurality of
nozzles; and tubing connecting said suppressant flow control module
to said port of said expansion bladder, wherein said nozzles are
disposed in a portion of said expansion bladder that partly defines
said interface volume.
4. The fire detection and suppression pack as recited in claim 1,
wherein said suppressant comprises an inert gas.
5. The fire detection and suppression pack as recited in claim 1,
wherein said suppressant comprises an organic halide gas.
6. The fire detection and suppression pack as recited in claim 1,
wherein said control processor is further configured to issue an
activation signal to said suppressant regulation and distribution
system when a temperature inside or outside the battery-powered
personal computing device equals or exceeds a second limit which is
lower than the first limit and a rate of temperature increase
equals or exceeds a third limit.
7. (canceled)
8. An assembly comprising a personal computing device and a fire
detection and suppression pack comprising an open box-like dock
case that supports said personal computing device, wherein said
personal computing device comprises a keyboard half and a display
half, said keyboard half comprising at least a battery and at least
one temperature sensor, and wherein said open box-like dock case is
secured to and configured to support said keyboard half seated
thereon with an interface volume therebetween such that said
keyboard half is accessible to a user when said display half is
raised and separated from said keyboard half, wherein said fire
detection and suppression pack further comprises: a source of
suppressant; a control processor connected to receive electrical
signals representing temperatures from said at least one
temperature sensor and configured to issue an activation signal
when a temperature inside the personal computing device equals or
exceeds a first limit set to indicate a fire event; and a
suppressant regulation and distribution system connected to said
source of suppressant, wherein said suppressant regulation and
distribution system is configured to discharge suppressant from
said source of suppressant and direct a flow of suppressant toward
the personal computing device in response to receipt of said
activation signal from said control processor, and wherein said
suppressant regulation and distribution system comprises: a
suppressant flow control module that is configured to discharge
suppressant from said source of suppressant in response to receipt
of said activation signal; an expansion bladder having a port and a
plurality of nozzles facing said interface volume; and tubing
connecting said suppressant flow control module to said port of
said expansion bladder, wherein said expansion bladder is arranged
so that suppressant flowing out through said plurality of nozzles
and into said interface volume will impinge upon a case of said at
least one battery or a portion of the case of the personal
computing device which is adjacent to the at least one battery.
9. The assembly as recited in claim 8, wherein said fire detection
and suppression pack further comprises a case having a first
attachment device attached thereto and a flexible sleeve having one
edge attached to said case and having a second attachment device
attached to another edge thereof, said flexible sleeve being
configured so that said second attachment device can be attached to
said first attachment device when a portion of said personal
computing device is disposed between said flexible sleeve and said
case of said fire detection and suppression pack.
10. An assembly comprising a personal computing device and a fire
detection and suppression pack attached to said personal computing
device, wherein said personal computing device comprises a case, at
least one battery and at least one temperature sensor, and wherein
said fire detection and suppression pack comprises: a source of
suppressant; a control processor connected to receive electrical
signals representing temperatures from said at least one
temperature sensor and configured to issue an activation signal
when a temperature inside the personal computing device equals or
exceeds a first limit set to indicate a fire event, and a
suppressant regulation and distribution system connected to said
source of suppressant, wherein said suppressant regulation and
distribution system is configured to discharge suppressant from
said source of suppressant and direct a flow of suppressant toward
the personal computing device in response to receipt of said
activation signal from said control processor, and wherein said
case of said personal computing device has an interior volume and a
first port that is in fluid communication with said interior
volume, and wherein said suppressant regulation and distribution
system comprises tubing connecting said source of suppressant to
said first port of said case to enable flow of suppressant from
said source of suppressant into said interior volume of said case
in response to said activation signal.
11. The assembly as recited in claim 10, wherein said control
processor comprises a microprocessor, said suppressant regulation
and distribution system comprises a switch, and said assembly
further comprises an electrical cable connecting said
microprocessor to said switch, at least a portion of said
electrical cable being disposed inside a corresponding portion of
said tubing.
12. The assembly as recited in claim 11, wherein said case has a
second port, said assembly further comprising an electrical plug
inserted in said second port, said electrical plug electrically
coupling said microprocessor to one or more electrical conductors
in said second port.
13. The assembly as recited in claim 12, wherein said first and
second ports are respective USB receptacles.
14. The assembly as recited in claim 8, wherein said source of
suppressant comprises a first canister filled with an organic
halide and a second canister filled with carbon dioxide.
15. The assembly as recited in claim 10, wherein said control
processor is further configured to issue an activation signal to
said suppressant regulation and distribution system when a
temperature inside the battery-powered personal computing device
equals or exceeds a second limit which is lower than the first
limit and a rate of temperature increase equals or exceeds a third
limit.
16. An assembly comprising a personal computing device and a fire
detection and suppression pack comprising an open box-like dock
case that supports said personal computing device, wherein said
personal computing device comprises a keyboard half and a display
half, said keyboard half comprising a battery and at least one
temperature sensor, and wherein said open box-like dock case is
secured to and configured to support said keyboard half seated
thereon with an interface volume therebetween such that said
keyboard half is accessible to a user when said display half is
raised and separated from said keyboard half, wherein said fire
detection and suppression pack further comprises: a source of
suppressant; an electronic valve connected to said source of
suppressant; an expansion bladder having a port and a plurality of
nozzles facing said interface volume; tubing connecting said
electronic valve to said port of said expansion bladder; and a
control processor connected to receive electrical signals
representing temperatures from said at least one temperature sensor
and configured to issue an activation signal when a temperature
inside the personal computing device equals or exceeds a first
limit set to indicate a fire event, wherein said electronic valve
opens to allow suppressant to flow from said source of suppressant
into said expansion bladder and then into said interface volume in
response to receipt of said activation signal from said control
processor.
17. The assembly as recited in claim 16, wherein said battery
comprises a case and said expansion bladder is arranged so that
suppressant flowing out through said plurality of nozzles will
impinge upon said case of said battery.
18-19. (canceled)
20. The method as recited in claim 21, further comprising forming
jets of suppressant that impinge on a battery case of the personal
computing device.
21. A method for mitigating fire risk during operation of a
battery-powered personal computing device onboard an aircraft,
comprising: (a) placing a fire detection and suppression pack
including a container containing suppressant onboard the aircraft;
(b) establishing a closed physical connection between the container
and the battery-powered personal computing device, which physical
connection is configured to provide a flow path for fluid when a
state of the physical connection is changed from closed to open;
(c) monitoring a temperature inside the battery-powered personal
computing device to determine whether a temperature inside the
battery-powered personal computing device is above or below a
specified threshold; (d) opening the physical connection in
response to a determination in step (c) that a temperature inside
the battery-powered personal computing device is above the
specified threshold; and (e) directing suppressant through a USB
receptacle and into a volume of space inside the case of the
personal computing device.
22. The method as recited in claim 21, wherein said suppressant
comprises a mixture of an organic halide and carbon dioxide.
23. (canceled)
24. The fire detection and suppression pack as recited in claim 10,
wherein said source of suppressant comprises a first canister
filled with an organic halide and a second canister filled with
carbon dioxide.
25. The fire detection and suppression pack as recited in claim 1,
further comprising a flexible plastic sleeve draped over said
keyboard half of said battery-powered personal computing device so
that said keyboard half of said battery-powered personal computing
device is secured to said open box-like dock case.
26. The fire detection and suppression pack as recited in claim 25,
further comprising: a bonded joint that attaches a first marginal
portion of said flexible plastic sleeve to one side of said open
box-like dock case; a first strip of hook-and-loop fastener fabric
attached to a second marginal portion of said flexible plastic
sleeve; and a second strip of hook-and-loop fastener fabric which
is bonded to another side of said open box-like dock case, wherein
said first and second strips of hook-and-loop fastener fabric form
a hook-and-loop fastener closure that allows for selective
tensioning of said flexible plastic sleeve.
Description
BACKGROUND
[0001] This disclosure is generally related to systems and methods
for suppressing fires in battery-powered personal use devices. In
particular, this disclosure relates to portable personal computing
devices powered by lithium-ion batteries.
[0002] A lithium-ion battery is a member of a family of
rechargeable battery types in which lithium ions move from an anode
to a cathode during discharge and from the cathode to the anode
when charging. Lithium-ion batteries are common in many consumer
electronics as they are one of the most popular types of
rechargeable batteries for personal computing devices.
[0003] Despite the positive attributes of lithium-ion batteries,
there have been concerns associated with their use. Lithium-ion
batteries are capable of spontaneous ignition and subsequent
explosion due to overheating. Overheating may be caused by
electrical shorting, rapid discharge, overcharging, manufacturer's
defect, poor design, or mechanical damage, among many other causes.
Overheating results in a process called thermal runaway, which is a
reaction within the battery causing internal temperature and
pressure to rise at a quicker rate then can be dissipated. Because
many airlines are replacing paper charts with laptops and tablet
computers, any risks associated with the use of lithium-ion
batteries onboard aircraft should be mitigated to the greatest
extent possible.
SUMMARY
[0004] The subject matter disclosed herein is directed to systems
and methods for mitigating the risk of and/or suppressing fires
caused by lithium battery-powered portable personal computing
devices and similar devices used or carried on the flight deck or
in crew and passenger compartments onboard an aircraft. In
accordance with some embodiments, an accessory unit (referred to
herein as a "fire detection and suppression pack") is attached to a
lithium-ion battery-powered portable personal computing device. The
fire detection and suppression pack has a weight and volume
consistent with the portable personal computing device and does not
impair the use of the portable personal computing device. The fire
detection and suppression pack is a full-time fire suppression
system that is on hot standby at all times, independent of the
computing device's power mode (i.e., on or off). The fire detection
and suppression pack uses gases (stored in canisters) to cool down
hot elements, deplete oxygen content, provide chemical flame
extinguishing of an existing flame, and inhibit reignition. The
fire detection and suppression pack provides a user-friendly,
lightweight, cost-effective means to match the preferred fire
fighting response to lithium-ion battery-powered devices and
systems.
[0005] In preferred embodiments, the total system integrates two
redundant suppression systems, each having a pressurized
suppressant cartridge and associated flow control valves and
plumbing. This redundancy allows the use of a single gas
suppressant in both cartridges, either Halon 1301 or CO.sub.2 or
the use of a mixed gas suppressant methodology, one cartridge with
CO.sub.2 to enhance cool-down effects and Halon 1301 to provide
chemical flame extinguishing. The mixed gas suppression methodology
provides greater fire suppression than does either the Halon 1301
or the CO.sub.2 alone. Both suppressants are considered clean
agents and leave no harmful residues after their use. This is a
major advantage over the use of some alternative suppressant that
requires clean up after its use. This has the advantage of allowing
a higher error rate in premature release of suppression, which
allows a quicker response time to be employed
[0006] The fire detection and suppression pack can be constructed
in an open box-like configuration that physically and functionally
interfaces with the lithium ion battery-powered personal computing
device. In some embodiments, the fire detection and suppression
pack serves as a cold dock on which a personal computing device can
be seated. The interface surface of the fire detection and
suppression pack that faces the battery-powered personal computing
device may consist of an array of surface nozzles that direct
suppressant gas flow onto a surface of the personal computing
device to cool it and provide a cold gas firewall at the interface.
The cold gas suppressant flow is initiated when a suppressant
discharge control processor detects fire event conditions and
releases the suppressant stored in cartridges located in fire
detection and suppression pack. Some of the released suppressant
floods into the interior volume of the battery-powered personal
computing device to cool down hot elements, deplete oxygen content,
provide chemical flame extinguishing of an existing flame and
inhibit reignition. The volume flooding can be accomplished at the
interface volume between the fire detection and suppression pack
and the battery-powered personal computing device using existing
cooling flow porting in the latter as well as suppressant flow
through a USB bridge assembly interface which directs additional
flooding suppressant flow into the interior volume of the personal
computing device.
[0007] In accordance with some embodiments, the suppressant
discharge control processor processes temperature signals taken
from the personal computing device's health monitoring BIOS and/or
temperature signals taken by the fire detection and suppression
pack itself. When these temperatures reach limits set to indicate a
fire event, the control processor sends a suppressant discharge
activation signal to a suppressant flow control system which
releases, directs and cycles the suppressant flow to the interfaces
between the lithium ion battery-powered personal computing device
and the fire detection and suppression pack.
[0008] One aspect of the subject matter disclosed in detail below
is a fire detection and suppression pack comprising: a support
structure configured to support a battery-powered personal
computing device with an interface volume therebetween; a source of
suppressant; a suppressant regulation and distribution system
connected to the source of suppressant; and a control processor
configured to issue an activation signal to the suppressant
regulation and distribution system when a temperature inside or
outside the battery-powered personal computing device equals or
exceeds a first limit set to indicate a fire event, wherein the
suppressant regulation and distribution system is configured to
release and direct a flow of suppressant from the source of
suppressant to the interface volume between the battery-powered
personal computing device and the fire detection and suppression
pack in response to receipt of the activation signal. In accordance
with some embodiments, the suppressant regulation and distribution
system comprises: a suppressant flow control module that is
configured to release suppressant from the source of suppressant in
response to receipt of the activation signal; an expansion bladder
having a port and a plurality of nozzles; and tubing connecting the
suppressant flow control module to the port of the expansion
bladder, wherein the nozzles are disposed in a portion of the
expansion bladder that partly defines the interface volume. The
suppressant may comprise an inert gas or an organic halide gas or a
mixture thereof.
[0009] In accordance with a further aspect of the fire detection
and suppression pack described in the preceding paragraph, the
control processor may be further configured to issue an activation
signal to the suppressant regulation and distribution system when a
temperature inside or outside the battery-powered personal
computing device equals or exceeds a second limit which is lower
than the first limit and a rate of temperature increase equals or
exceeds a third limit.
[0010] Another aspect of the subject matter disclosed in detail
below is an assembly comprising a personal computing device and a
fire detection and suppression pack attached to the personal
computing device, wherein the personal computing device comprises a
case, at least one battery and at least one temperature sensor, and
wherein the fire detection and suppression pack comprises: a source
of suppressant; a control processor connected to receive electrical
signals representing temperatures from the at least one temperature
sensor and configured to issue an activation signal when a
temperature inside the personal computing device equals or exceeds
a limit set to indicate a fire event, and a suppressant regulation
and distribution system connected to the source of suppressant,
wherein the suppressant regulation and distribution system is
configured to release suppressant from the source of suppressant
and direct a flow of suppressant toward the personal computing
device in response to receipt of the activation signal from the
control processor. In accordance with some embodiments, the
suppressant regulation and distribution system comprises: a
suppressant flow control module that is configured to release
suppressant from the source of suppressant in response to receipt
of the activation signal; an expansion bladder having a port and a
plurality of nozzles; and tubing connecting the suppressant flow
control module to the port of the expansion bladder, wherein the
nozzles are disposed in a portion of the expansion bladder that
partly defines the interface volume. The expansion bladder may be
arranged so that suppressant flowing out through the plurality of
nozzles will impinge upon a case of the at least one battery or a
portion of the case of the personal computing device which is
adjacent to the at least one battery.
[0011] In accordance with one embodiment, the case of the personal
computing device has an interior volume and first and second ports
that are in fluid communication with that interior volume; the
control processor comprises a microprocessor; the suppressant
regulation and distribution system comprises a switch and tubing
connecting the source of suppressant to the first port of the case
to enable flow of suppressant from the source of suppressant into
the interior volume of the case in response to the switching
receiving the activation signal; and the assembly further comprises
an electrical plug inserted in the second port and an electrical
cable connecting the microprocessor to the switch, at least a
portion of the electrical cable being disposed inside a
corresponding portion of the tubing. In some cases, the first and
second ports are respective USB receptacles.
[0012] In accordance with some embodiments of the assembly, the
fire detection and suppression pack further comprises a case having
a first attachment device attached thereto and a flexible sleeve
having one edge attached to the case of the fire detection and
suppression pack and having a second attachment device attached to
another edge thereof, the flexible sheet being configured so that
the second attachment device can be attached to the first
attachment device when a portion of the personal computing device
is disposed between the flexible sleeve and the case of the fire
detection and suppression pack.
[0013] A further aspect of the subject matter disclosed in detail
below is an assembly comprising a personal computing device and a
dock that supports the personal computing device, wherein the
personal computing device comprises a battery and at least one
temperature sensor, and wherein the dock comprises: a source of
suppressant; an electronic valve connected to the source of
suppressant; an expansion bladder having a port and a plurality of
nozzles; tubing connecting the electronic valve to the port of the
expansion bladder; and a control processor connected to receive
electrical signals representing temperatures from the at least one
temperature sensor and configured to issue an activation signal
when a temperature inside the personal computing device equals or
exceeds a limit set to indicate a fire event, wherein the
electronic valve opens to allow suppressant to flow from the source
of suppressant into the expansion bladder in response to receipt of
the activation signal from the control processor. In some
embodiment, the battery comprises a case and the expansion bladder
is arranged so that suppressant flowing out through the plurality
of nozzles will impinge upon the case of the battery.
[0014] Yet another aspect of the subject matter disclosed in detail
below is a method for mitigating fire risk during operation of a
battery-powered personal computing device onboard an aircraft,
comprising: (a) placing a fire detection and suppression pack
including a container containing suppressant onboard the aircraft;
(b) establishing a closed physical connection between the container
and the battery-powered personal computing device, which physical
connection is configured to provide a flow path for fluid when a
state of the physical connection is changed from closed to open;
and (c) monitoring a temperature inside the battery-powered
personal computing device to determine whether a temperature inside
the battery-powered personal computing device is above or below a
specified threshold. If a fire event occurs, the method may further
comprise opening the physical connection in response to a
determination in step (c) that a temperature inside the
battery-powered personal computing device is above the specified
threshold. This method may further comprise one or both of the
following: (a) forming jets of suppressant that impinge on a
battery case of the personal computing device; and/or (b) directing
suppressant through a USB receptacle and into the volume of space
inside the case of the personal computing device.
[0015] Other aspects of systems and methods for preventing or
suppressing fires caused by lithium battery-powered personal
computing devices are disclosed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a block diagram identifying some components of a
system for detecting and suppressing a fire in a portable personal
computing device in accordance with various embodiments.
[0017] FIG. 2 is a flowchart identifying steps of a method for
detecting and suppressing a fire in a portable personal computing
device in accordance with one embodiment.
[0018] FIG. 3A is a diagram showing a closed clam-shell tablet
computer being lowered toward a fire detection and suppression
pack.
[0019] FIG. 3B is a diagram showing a fire detection and
suppression pack attached to a tablet computer by means of a
flexible plastic sleeve that lies between the respective halves of
the table computer and is attached in two places to the case of the
fire detection and suppression pack.
[0020] FIG. 3C is a diagram representing a front view (as indicated
by arrows 3C in FIG. 3B) of the flexible plastic sleeve draped
across the lower half of the tablet computer when the other half,
i.e., the display panel, of the tablet computer is raised.
[0021] FIG. 4 is a diagram representing a sectional view of a fire
detection and suppression pack attached to a laptop computer in
accordance with other embodiments.
[0022] FIGS. 5A and 5B are diagrams representing respective
sectional views of respective portions of a fire detection and
suppression pack and a tablet computer in accordance with some
embodiments. The fire detection and suppression pack is shown in
two different states: before initiation of impingement flow of
suppressant gas on a surface of the notebook computer (FIG. 5A) and
after initiation of such impingement flow.
[0023] FIG. 6 is a diagram representing a top view of a fire
detection and suppression pack having four expansion bladders with
impingement flow nozzles. The bold dash-dot lines indicate the
location of the lithium ion battery pack. FIG. 6 also shows the
configuration of a bladder manifold in accordance with one
embodiment.
[0024] FIG. 7 is a hybrid diagram comprising a sectional view of a
portion of a fire detection and suppression pack (of the type
partially depicted in FIG. 5B) attached to a tablet computer, a
plan view of a USB bridge assembly, and a flow path diagram
representing some components of the suppressant flow control
module. Preferably the suppressant flow control module is inside
the case of the fire detection and suppression pack, while the USB
bridge assembly connects the cases of the tablet computer and fire
detection and suppression pack.
[0025] FIG. 7A is a diagram showing the plan view of the
suppressant flow control module seen in FIG. 7 on a magnified
scale.
[0026] FIG. 7B is a diagram showing the plan view of the USB bridge
assembly seen in FIG. 7 on a magnified scale.
[0027] Reference will hereinafter be made to the drawings in which
similar elements in different drawings bear the same reference
numerals.
DETAILED DESCRIPTION
[0028] Various embodiments of systems and methods for detecting and
suppressing fires in portable personal computing devices will now
be described in detail for the purpose of illustration. At least
some of the details disclosed below relate to optional features or
aspects, which in some applications may be omitted without
departing from the scope of the claims appended hereto.
[0029] FIG. 1 is a block diagram identifying some components of a
system for detecting and suppressing a fire in a battery-powered
personal computing device 8. In accordance with various
embodiments, the personal computing device 8 comprises a lithium
ion battery 10. The temperatures inside the personal computing
device 8 are detected using temperature sensors 12 (e.g.,
thermistors). The detection/suppression system may take the form of
a fire detection and suppression pack 6 which is attached to the
personal computing device 8. The fire detection and suppression
pack 6 is configured to support the particular battery-powered
personal computing device with an interface volume
therebetween.
[0030] In accordance with some embodiments, the fire detection and
suppression pack 6 comprises a cartridge 18 containing a
suppressant A, a cartridge 20 containing a suppressant B, a
suppressant regulation and distribution system 16 connected to
cartridges 18 and 20, and a suppressant discharge control processor
14 connected to receive electrical signals representing
temperatures inside the battery-powered personal computing device
from the temperature sensors 12. In accordance with other
embodiments, the fire detection and suppression pack 6 may have
only a single suppressant cartridge or more than two suppressant
cartridges.
[0031] The suppressant discharge control processor 14 is configured
(i.e., programmed) to issue an activation signal to the suppressant
regulation and distribution system 16 when a temperature inside the
battery-powered personal computing device 8 equals or exceeds a
limit set to indicate a fire event. The suppressant regulation and
distribution system 16 is configured to discharge and direct a flow
of mixed suppressant gases from the cartridges 18 and 20 to an
interface volume between the battery-powered personal computing
device 8 and the fire detection and suppression pack 6 in response
to receipt of the activation signal from the suppressant discharge
control processor 14. More specifically, a mixture of suppressant
gases may be injected into an interior volume of the case of the
personal computing device and/or directed to impinge upon a case of
the lithium ion battery 10, as will be described in more detail
below with reference to FIGS. 4 and 5B. In accordance with one
embodiment, suppressant A is an inert gas (e.g., carbon dioxide)
and suppressant B is an organic halide gas (e.g., Halon 1301).
[0032] As will be described in detail below, in accordance with
some embodiments, the suppressant regulation and distribution
system 16 comprises: (a) a suppressant flow control module that
responds to the activation signal by discharging suppressant gas;
(b) one or more expansion bladders each having an array of nozzles
that direct some of the suppressant gas discharged by the
suppressant flow control module onto an exterior surface of and/or
through venting ports into the interior volume of the
battery-powered personal computing device 8; and (c) a flow channel
that directs some of the suppressant gas discharged by the
suppressant flow control module through a USB or other receptacle
and into the interior volume of the battery-powered personal
computing device 8.
[0033] FIG. 2 is a flowchart identifying steps of a method for
detecting and suppressing a fire in a portable personal computing
device in accordance with one embodiment. The temperature sensors
12 inside the portable personal computing device 8 detect the
battery cell temperature 22, the interior air volume temperature
24, and the battery case surface temperature 26. These temperatures
are input to the suppressant discharge control processor 14 that
performs temperature monitoring (step 28). In accordance with the
embodiment depicted in FIG. 2, a determination is made whether the
interior air volume temperature 24 is equal to or greater than a
specified threshold (step 30), e.g., 125.degree. F. The thresholds
for the battery cell temperature 22 and the battery case surface
temperature 26 will be set higher. If at least one of the battery
cell temperature 22, the interior air volume temperature 24, and
the battery case surface temperature 26 equals or exceeds a
respective specified threshold, then suppressant discharge is
initiated (step 32).
[0034] In alternative implementations, suppressant discharge can be
initiated when one of the monitored temperatures equals or exceeds
a first specified threshold or when the same monitored temperature
equals or exceeds a second specified threshold (less then the first
specified threshold) and the rate of temperature increase equals or
exceeds a third specified threshold. For example, the suppressant
discharge control processor 14 may be configured to issue an
activation signal when the ambient interior air temperature inside
the personal computing device equals or exceeds a first limit
(e.g., T.sub.A.gtoreq.60.degree. C.) or when the ambient interior
air temperature equals or exceeds a second limit which is lower
than the first limit (e.g., T.sub.A.gtoreq.45.degree. C.) and the
rate of temperature increase equals or exceeds a third limit (e.g.,
dT.sub.A/dt.gtoreq.+3.degree. C./sec).
[0035] In some embodiments, the system uses two independent
temperature sensing systems: temperature sensors incorporated in
the personal computing device's internal system (e.g., the basic
input/output system, BIOS, which comprises firmware) and contact
temperature sensors on the surface of the fire detection and
suppression pack 6. The suppressant discharge control processor 14
compares the temperature inputs against preset limits. A continuous
voting process is used to initiate suppressant discharge by the
suppressant flow control module (part of the suppressant regulation
and distribution system 16) when one or more limits are
exceeded.
[0036] The baseline fire detection and suppression apparatus,
associated methodologies, principles and hardware can be applied
across the market spectrum of lithium ion battery-powered personal
computing devices and systems. The case of the fire detection and
suppression pack 6 can be custom configured to accommodate the
differences in form factors, dimensions, battery pack locations
between different manufacturers and between different models from
the same manufacturer.
[0037] FIG. 3A is a diagram showing a closed clam-shell tablet
computer 8a being lowered toward a fire detection and suppression
pack 6a. An interface volume 34 between the tablet computer case 38
and the cold dock case is indicated by a double-headed arrow in
FIG. 3A. FIG. 3B shows fire detection and suppression pack 6a
attached to tablet computer 8a. When the tablet computer 8a is
attached to the fire detection and suppression pack 6a, they form
an integrated stand-alone fire detection and suppression
system.
[0038] As best seen in FIG. 3B, the tablet computer 8a is powered
by a lithium ion battery 10. The tablet computer 8a comprises a
computer case 38 having at least one USB receptacle 36. The fire
detection and suppression pack 6a comprises a cold dock case 42,
two suppressant cartridges (only the suppressant A cartridge is
visible), a suppressant flow control module 52, and four expansion
bladders (only expansion bladders 44a and 44b are visible). The
cold dock case 42 has a USB receptacle 46. In this particular
embodiment, attachment consists of securing the cold dock case 42
to the keyboard half 62 of the tablet computer 8a and plugging a
USB bridge assembly 50 into the USB receptacles 46 and 50.
[0039] The fire detection and suppression pack 6a is attached to
the tablet computer 8a by means of a flexible plastic sleeve 40
(indicated by a straight dashed line) that lies between the display
half 60 and the keyboard half 62 of the tablet computer 8a. As best
seen in FIG. 3C, the flexible plastic sleeve 40 is attached in two
places to the cold dock case 42 and draped across the keyboard half
62 of the tablet computer 8a of the tablet computer when the
display half 60 of the tablet computer 8a is raised and separated
from keyboard half 62. A first marginal portion of the flexible
plastic sleeve 40 is attached to one side of the cold dock case 42
by means of a bonded joint 64; a second marginal portion of the
flexible plastic sleeve 40 has a strip of hook-and-loop fastener
fabric attached thereto, which strip can be attached to another
strip of hook-and-loop fastener fabric which is bonded to the other
side of the cold dock case 42 to form a hook-and-loop fastener
closure 66 that allows for selective tensioning of the flexible
plastic sleeve 40. The tensioned flexible plastic sleeve 40 retains
the tablet computer 8a on the fire detection and suppression pack
6a.
[0040] The flexible plastic sleeve 40 may take the form of a thin
elastic ultra-high-molecular-weight polyethylene sleeve customized
to fit the specific make and model of personal computing device
that the fire detection and suppression pack cold dock is being
used on. This sleeve allows for touch screen applications or may
have key pad cutouts as well as other cutouts to accommodate
switches, USB ports and other features.
[0041] FIG. 4 is a diagram representing a sectional view of a fire
detection and suppression pack 6b attached to a laptop computer 8b
powered by a lithium ion battery 10. The lithium ion battery
comprises a lithium ion battery cell 72 housed in a battery case
70. The lithium ion battery 10 powers the electrical components of
the laptop computer 8b via a battery circuit/connector 74. The fire
detection and suppression pack 6a comprises a cold dock case 42,
two suppressant cartridges (only the suppressant A cartridge is
visible), a suppressant flow control module (not shown in FIG. 4),
and four expansion bladders (only expansion bladders 44a and 44b
are visible).
[0042] In FIG. 4, the fire detection and suppression pack 6a is
shown in a state immediately following initiation of suppressant
discharge. The discharge of pressurized suppressant causes the
expansion bladders to inflate. The expansion bladders have nozzles
that dilate (i.e., open) as the bladder expands. The expansion
bladders and nozzles may be made of nylon or any other suitable
high-temperature elastic material (e.g., possibly
polyurethane).
[0043] In the example depicted in FIG. 4, expansion bladder 44a is
disposed underneath the lithium ion battery 10. As seen in FIG. 4,
when expansion bladder 44a is expanded, jets of suppressant gas (as
indicated by parallel arrows A) exiting the bladder will impinge
directly on the portion of the computer case 38 that is adjacent to
and in contact with the battery case 70, thereby cooling the
lithium ion battery 10 and suppressing any fire condition. When
expansion bladder 44b is expanded, jets of suppressant gas (as
indicated by parallel arrows B) will enter the interior volume of
the laptop computer 8b via cooling system vents built into the
computer case 38. (Laptops and tablets have various cooling schemes
and cooling flow inlets and outlets.) This flow of suppressant gas
will circulate (as indicated by curved arrows C and straight arrow
D) inside the tablet computer 8a, thereby providing additional
cooling and fire suppression for the lithium ion battery 10.
[0044] FIGS. 5A and 5B are diagrams representing respective
sectional views of respective portions of a fire detection and
suppression pack 6a and a tablet computer 8a in accordance with
some embodiments. The fire detection and suppression pack 6a is
shown in two different states: before initiation of impingement
flow of suppressant gas on a bottom surface of the computer case 38
(FIG. 5A) and after initiation of such impingement flow (FIG.
5B).
[0045] As depicted in FIG. 5A, during normal operation (i.e., when
temperatures inside the tablet computer 6a are below the
suppressant discharge temperature), ambient air can flow (as
indicated by arrows E) into and through an interface volume 76
formed by the confronting surfaces of the fire detection and
suppression pack 6a and tablet computer 8a. The circulating ambient
air provides cooling. In the state depicted in FIG. 5A, the
labyrinth seal 56 is retracted, the impingement flow nozzles 48 are
constricted, and the expansion bladder 44a is in a collapsed
state.
[0046] In contrast, when suppression discharge is initiated (i.e.,
when temperatures inside the tablet computer 6a are equal to or
above the suppressant discharge temperature), discharged
suppressant gas will flow via an expansion bladder into and then
out of the interface volume 76 (as indicated by arrows G in FIG.
5B). Flooding of the interface volume 76 between the fire detection
and suppression pack 6b and tablet computer 8a is accomplished
using the expansion bladders (e.g., expansion bladder 44a). In the
state depicted in FIG. 5B, the labyrinth seal 56 is extended, the
impingement flow nozzles 48 are dilated, and the bladder 44a is
expanded by the suppressant gas pressure prior to exiting the
impingement flow nozzles 48. The expansion bladder 44a is inflated
by the pressurized suppressant gas flowing through the bladder
manifold 54, one end of which is connected to a port of the
expansion bladder 44a and the other end of which is in fluid
communication with the suppressant flow control module (not shown
in FIGS. 5A and 5B).
[0047] The labyrinth seal 56 on the perimeter of each bladder
maintains a positive pressure in the interface volume 76, which
forces suppressant flow through and out of the interface volume 76.
In the case of an expansion bladder disposed under cooling system
vents in the computer case 38, the labyrinth seal 56 will maintain
a positive pressure which forces suppressant flow into the interior
volume of the tablet computer 8a through those cooling system
vents.
[0048] The pressurized discharged suppressant flow entering the
expansion bladders expands them against the bottom surface of the
case of the personal computing device. The dimensions of perimeter
labyrinth seals 56 establishes the impingement cooling jet offset
from the bottom surface of the computer case 38. The perimeter
labyrinth seals 56 also maintain a positive pressure in the flooded
interface volume 76 between the expansion bladders and the personal
computing device. This positive pressure forces flooding flow into
the interior volume of the personal computing device through its
ambient air cooling paths. Volume flooding of the interface volume
76 and the interior volume of the personal computing device cools
hot surfaces, prevents sparking, and extinguishes any flame sources
that may ignite or reignite a fire in the personal computing
device.
[0049] FIG. 6 is a diagram representing a top view of a fire
detection and suppression pack having four expansion bladders
44a-44d disposed in four quadrants of the pack. Each expansion
bladder 44a-44d comprises a respective array of impingement flow
nozzles 48 disposed on the side of the bladder that faces the
personal computing device. The bold dash-dot lines indicate the
location 10' of a lithium ion battery pack inside the personal
computing device. FIG. 6 also shows one configuration of a bladder
manifold 54 which is biased to concentrate the cooling flow of
suppressant toward the battery pack. Preferably, the expansion
bladders direct high-density jetted cooling flow that impinges on
the bottom surface of the computer case 38 adjacent to the location
10' of the lithium ion battery pack, with less dense jetted flow on
other portions of the bottom surface.
[0050] FIG. 7 is a hybrid diagram comprising a sectional view of a
portion of a fire detection and suppression pack (of the type
partially depicted in FIG. 5B) attached to a tablet computer 8a, a
plan view of a USB bridge assembly 78, and a flow path diagram
representing other components of the suppressant regulation and
distribution system 16 depicted in FIG. 1, including a suppressant
flow control module 90 and a gas flow manifold 102. Preferably the
suppressant flow control module 90 is disposed inside the cold dock
case 42, The USB bridge assembly 78 comprises a pitchfork-shaped
bridge 80 that forms a conduit for suppressant flow that may be
considered part of the suppressant regulation and distribution
system 16. The USB bridge assembly 78 connects to the computer case
38 of the tablet computer 8 and to the cold dock case 42; and is
designed to convey electrical signals from the tablet computer 8 to
the suppressant flow control module 90 and convey suppressant gas
from the suppressant flow control module 90 to the tablet computer
8.
[0051] Still referring to FIG. 7, the USB bridge assembly 78
comprises a suppressant discharge control microprocessor 86 which
receives temperature inputs 2 from the tablet computer's internal
system and temperature inputs 4 from contact temperature sensors
attached to the surface of the cold dock case 42. The suppressant
discharge control microprocessor 86 monitors and processes the
temperature inputs, and outputs flow control command signals to the
suppressant flow control system 90. In accordance with some
embodiments, the suppressant discharge control microprocessor 86
compares the received temperatures and their rate of change to
respective preset (i.e., specified) temperature and rate of change
limits. When one or more of these limits are exceeded, a voting
algorithm determines whether the suppressant should be discharged
or not. A Yes vote outcome results in an open command signal being
transmitted to the suppressant flow control system 90.
[0052] FIG. 7A represents a plan view of USB bridge assembly 78 in
accordance with one embodiment. The bridge 80 comprises three
conduits 80a, 80b, and 80c that intersect at a common junction. The
conduits are preferably fabricated from plastic, rubber or
composite materials. The distal end of conduit 80a is connected to
a USB plug 82a that is fittable into a first USB receptacle
integrated into the computer case 38 (partly indicated by dash-dot
lines). The distal end of conduit 80c is connected to a flow
connector 84 that is coupled to the cold dock case 42 (partly
indicated by dash-dot lines). Since the conduits 80a and 80c are in
fluid communication, suppressant gas discharged by the suppressant
flow control module 90 (see FIG. 7) can flow through a gas flow
manifold 102, flow connector 84, conduits 80c and 80a, and USB plug
82a, and into the interior volume of the computer case 38 by way of
the aforementioned first USB receptacle in the computer case
38.
[0053] Still referring to FIG. 7A, the distal end of the middle
conduit 80b is connected to a USB plug 82b that is fittable into a
second USB receptacle integrated into the computer case 38. In
accordance with this embodiment, the suppressant discharge control
microprocessor 86 is seated in the middle conduit 80b. As
previously mentioned, the suppressant discharge control
microprocessor 86 receives, monitors and processes the temperature
inputs from the temperature sensors 12 (see FIG. 1). The
suppressant discharge control microprocessor 86 is electrically
connected to a USB plug 82c by means of an electrical cable 88. The
portion of electrical cable 88 closest to the suppressant discharge
control microprocessor 86 is disposed inside the middle conduit
80b. The remainder of electrical cable 88 passes through a wall of
the bridge 80 and terminates at a USB plug 82c, which is fittable
into a USB receptacle integrated into the cold dock case 42. In
response to a fire event, the suppressant discharge control
microprocessor 86 sends an activation signal via electrical cable
88 and USB plug 82c to the suppressant flow control module 90 (see
FIG. 7). This activation signal initiates the discharge of
suppressant by the suppressant flow control module 90.
[0054] FIG. 7B represents a plan view of the suppressant flow
control module 90 on a magnified scale. The suppressant flow
control module 90 consists of the hardware used to control and
condition the pressurized suppressant discharge flow. It is a dual
redundant system with two subsystems: one subsystem controls the
flow of suppressant A from pressurized cartridge 18 and the other
subsystem controls the flow of suppressant B from pressurized
cartridge 20. Both subsystems are configured and sized as
stand-alone systems capable of suppressing a lithium-ion
battery-powered personal computing device/system fire event.
Combined they provide the added benefit of a mixed gas suppressant
system. In accordance with some embodiments, suppressant A is
carbon dioxide and suppressant B is Halon 1301. Both carbon dioxide
and Halon 1301 are considered clean agents and when mixed, provide
a multiplier effect in there fire-suppression capabilities. The use
of cartridge-stored suppressant allows the use of alternate
suppressants to match the future use of advanced power storage
technologies.
[0055] As depicted in FIG. 7B, the activation signal is received by
a suppressant discharge micro-switch 92, which is part of the
suppressant flow control module 90. The suppressant discharge
micro-switch 92 is normally Off. In response to the activation
signal, the suppressant discharge micro-switch 92 provides
electrical power to a pair of solenoid on-off valves 96a, 96b. Each
subsystem is triggered by when a respective solenoid on-off valve
96a, 96b changes state from off to on. A respective in-line
pressure regulator 98a, 98b reduces the system pressure from the
storage gas pressure to the design working pressure. Respective
mixer unions 100a, 100b are used to combine the two suppressant
flows into one mixed gas flow. Each subsystem of the suppressant
control module 90 further comprises respective pressure relief
valves 99a, 99b. In addition to automated suppressant discharge, a
manual discharge trigger 94 with on/off safety can be manipulated
by the user of the personal computing device.
[0056] Returning to FIG. 7, the mixed gas flow exiting the mixer
unions 100a, 100b follows various flow paths dictated by the shape
of a gas flow manifold 102. The gas flow manifold 102 has
respective branches that distribute the suppressant gas flow to the
expansion bladders (e.g., expansion bladder 44a) and to the USB
bridge 80. The USB bridge 80 routes suppressant flooding flow
directly into the interior volume of the computer case 38 via
conduits 80c and 80a and the USB plug 82a.
[0057] In general, the USB bridge assembly end fittings can be
selected to meet the type and number of receptacles available. In
the situation where the computing device has only one receptacle,
the USB bridge assembly would be designed with concentric data
transmission and suppressant flow paths.
[0058] Activation of the suppression flow control module 90 floods
the volume at the interface between the battery-powered personal
computing device and the fire detection and suppression system 16.
This places a cold gas fire barrier at the interface.
[0059] In accordance with some embodiments, the suppression gas is
a mixture of carbon dioxide and Halon 1301. Halon 1301 (CBrF) works
by a combination of chemical and physical effects. The chemical
effect, which is dominant is achieved by the atoms in the gas
directly inhibiting combustion. Cold CO.sub.2 gas is used to reduce
the temperature of hot surfaces below the electrolyte vapor
combustion temperature. Mixed CO.sub.2 and Halon 1301 gas reduces
the volume content of oxygen below the level necessary to support
fire. The atoms in Halon 1301 gas chemically react directly with
the flame chemistry to inhibit combustion. Mixing CO.sub.2 and
Halon 1301 has been shown to have a multiplier effect.
[0060] The physical effects of the suppressant gas mixture are
temperature reduction and dilution. Temperature reduction occurs
whenever a non-reactive gas is added to a flammable gas, because
the heat liberated by the reaction of oxygen molecules with a fuel
source must be distributed into the overall environment. The rate
of the combustive chemical reaction decreases rapidly with
reductions in temperature and, if the concentration of added inert
gas is high enough, the flame chemistry fails altogether. Halon gas
mixtures are not only inert but are low temperature when released
from their pressurized state. Dilution is a simple matter of
reducing the collision frequency of the oxygen and fuel source so
that there is a reduction in chemical reaction rates. The magnitude
of this effect, however, is relatively small compared to chemical
inhibition and thermal effects, the former of these being the
predominant one.
[0061] Several properties of carbon dioxide make it an attractive
fire suppressant. It is not combustible and thus does not produce
its own products of decomposition. Carbon dioxide provides its own
discharge pressurization and leaves no residue. Carbon dioxide is
relatively nonreactive with most other materials. It provides
three-dimensional protection because it is a gas under ambient
conditions. It is electrically nonconductive and can be used in the
presence of energized electrical equipment.
[0062] Flame extinguishment by carbon dioxide is predominantly by a
thermophysical mechanism in which reacting gases are prevented from
achieving a temperature high enough to maintain the free radical
population necessary for sustaining the flame chemistry. For inert
gases presently used as fire suppression agents (argon, nitrogen,
carbon dioxide, and mixtures of these), the extinguishing
concentration is linearly related to the heat capacity of the
agent-air mixture. Although of minor importance in accomplishing
fire suppression, carbon dioxide also dilutes the concentration of
the reacting species in the flame, which slows the rate of heat
release.
[0063] Each of the embodiments described above provides a method
for mitigating fire risk during operation of a battery-powered
personal computing device onboard an aircraft. The method
comprises: (a) placing a fire detection and suppression pack
including a container containing suppressant onboard the aircraft;
(b) establishing a closed physical connection between the container
and the battery-powered personal computing device, which physical
connection is configured to provide a flow path for fluid when a
state of the physical connection is changed from closed to open;
(c) monitoring a temperature inside the battery-powered personal
computing device to determine whether a temperature inside the
battery-powered personal computing device is above or below a
specified threshold; and (d) opening the physical connection in
response to a determination in step (c) that a temperature inside
the battery-powered personal computing device is above the
specified threshold. The method may involve forming jets of
suppressant that impinge on a battery case of the personal
computing device and/or directing suppressant through a receptacle
and into a volume of space inside the case of the personal
computing device.
[0064] The personal computing device may have a lithium-containing
battery comprises a single lithium ion battery cell, a battery pack
comprising a plurality of individual lithium ion battery cells
housed inside of the battery pack, or a combination thereof.
[0065] While apparatus and methods for mitigating fire risk during
operation of a battery-powered personal computing device onboard an
aircraft have been described with reference to various embodiments,
it will be understood by those skilled in the art that various
changes may be made and equivalents may be substituted for elements
thereof without departing from the scope of the claims set forth
hereinafter. In addition, many modifications may be made to adapt
the teachings herein to a particular situation without departing
from the scope of the claims.
[0066] As used in the claims, the term "personal computing device"
may include, but is not limited to, a laptop computer, a tablet
computer, a computer notebook, a smartphone, a personal data
assistant, or other hand-held computer.
* * * * *