Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to vaults and strongrooms.
Banks and other institutions are commonly
provided with a vault or strongroom - which terms are
embraced collectively hereafter, and in the claims, by
the term "vault" alone - for the safekeeping of money
and other valuables. It has long been recognized that
there is danger if one or more persons become locked
within the vault, and in this respect it is not un-
common for ventilators or other devices to be provided
through which air, and possibly also sustenance, may
be passed to anybody trapped inside. However it must
be recognized that the provision of ventilation or
other access to the enclosure of the vault provides a
potential avenue for attack on its physical security.
In particular, ventilators may readily enable entry of
explosives.
In order to provide maximum assurance of physical
security of a vault and avoid compromising its
integrity under attack, it is desirable that the
enclosure be completely sealed. There is then the
distinct danger that any person locked inside will
suffocate before release comes or relief can be
provided. The danger is intensified significantly
where a time lock is used on the vault door, and
although safety procedures can be adopted to minimize
the likelihood of anybody being trapped accidentally,
the danger cannot be entirely eliminated. In the
latter respect furthermore, there is always the
possibility that where a robbery is committed, staff
or others may be locked in the vault in order to delay
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the raising of alarm and pursuit of the miscreants. If
a large number of persons were forceably entrapped in
this way, death could easily result unless release,
or action to breach the door or wall to provide vent-
ilation, is undertaken from the outside immediately, andis quickly achieved.
It is one of the objects of the present invention
to make provision for life support within a vault that
will enable the above-mentioned danger to be signifi-
cantly reduced without compromising physical security.It is another of the objects of the present invention
to provide a method for life support within a vault.
According to one aspect of the present invention
there is provided in a vault having impermeable walls
defining an enclosure and a door to seal said enclosure
air-tight, a monitor device communicating with the
atmosphere within the sealed enclosure of the vault to
monitor a first of two variables of said atmosphere, said
first variable being the carbon-dioxide content of the
atmosphere within said sealed enclosure, first means in
said sealed enclosure coupled with said monitor device
for responding to the condition in which the monitored
carbon-dioxide content exceeds a predetermined value to
remove carbon dioxide from said atmosphere, and second
means in said sealed enclosure for maintaining the second
of said two variables of said atmosphere within pre-
determined limits, said second means including gas-
storage means for supplying oxygen to said sealed
enclosure by release from said gas-storage means, and
means for regulating supply of said oxygen from said gas-
storage means to said sealed enclosure to maintain the
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said second variable within said limits.
According to another aspect of the present invention
there is provided a method of life support in a vault,
comprising the steps of monitoring a first of two varia-
bles of the atmosphere within the enclosure of the vault,said first variable being the carbon-dioxide content of
said atmosphere, responding to the condition in which the
monitored carbon-dioxide content exceeds a predetermined
value to remove carbon dioxide from said atmosphere, said
step of removing carbon-dioxide including passing air of
said atmosphere through material (for example, soda li~e
or lithium hydroxide) for absorbing carbon-dioxide,
introducing gas-storage means containing oxygen into the
vault and admitting oxygen to the said enclosure by
release of gas from said gas-storage means to maintain
the second of said two variables within predetermined
limits.
The controlled admission of oxygen in accordance
with either of the above aspects of the invention may be
20 made such as to maintain the atmospheric pressure within
the enclosure substantially constant or at least within
predetermined limits. Some other variable of the atmos-
phere, for example oxygen content, may however be used as
the criterion foradmission instead of, or as well as,
pressure.
The oxygen may be admitted to the enclosure alone or
in combination with other gases - as air for example -
from high-pressure cylinders. It may be via one or more
valves that are pre-set so that when opened its rate of
of admission is appropriate to replacement of the
carbon-dioxide removed from the atmosphere of
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the enclosure.
The monitor device and the said first and secondmeans may be provided together with means for emergency
illumination, as one unitary and self-contained piece
of equipment within the vault.
A vault equipped in accordance with the present
invention, together with a method of life support
therein, will now be described, by way of example, with
reference to the accompanying drawing. The drawing
shows the vault and its incorporated life-support
facilities in schematic form.
Referring to the drawing, the enclosure 1 of the
vault is sealed by a door 2 and contains life-support
equipment 3 of unitary and self-contained form. The
equipment 3 incorporates one or more cylindrical
vessels 4 that contain soda lime or other material for
removal of carbon dioxide from the atmosphere of the
enclosure 1 by absorption, together with one or more
oxygen cylinders 5. A unit 6, which includes a
device 7 for monitoring the carbon-dioxide content of
the atmosphere, controls operation of a suction pump 8
for drawing air of the enclosure 1 through the one or
more vessels 4. The device 7 may be a device of a
known, commercially-available kind that periodically
samples the atmosphere and compares two parts of each
sample with one another after one of these parts has
been passed through carbon-dioxide absorbing material.
The unit 6 responds to the condition in which the
monitor device 7 detects that the carbon-dioxide
content of the atmosphere has risen to a pre-set value,
typically 1% or 2%, to operate the pump 8. A fan 9
is also operated from the unit 6 at this time to
circulate air in the enclosure 1, and operation of
both devices 8 and 9 is continued from the unit 6 for
a predetermined interval of time or until the monitored
carbon-dioxide content has been reduced to some pre-
set lower value, typically 0.5%.
An electrically-operated valve-device 10 is
provided for regulating admission of oxygen to the
atmosphere of the enclosure 1 from the one or more
cylinders 5. The valve device 10 is operated from
the monitor unit 6 to release oxygen for replacing the
absorbed carbon dioxide and maintaining a suitable
oxygen level, for example, of about 18% or 19%, in the
enclosure 1. More especially, the valve device 10 is
operated to maintain a variable of the atmosphere
other than the carbon-dioxide content as monitored by
the monitor device 7, substantially constant at a
pre-set, normal value, or alternatively to maintain
it within some predetermined limits. This other
variable may be ambient atmospheric pressure, and to
this end the device 10 might be arranged to release
oxygen at a rate dependent on atmospheric pressure as
sensed within the enclosure 1 by a pressure-sensitive
monitor device (not shown) provided within the unit 6.
On the other hand, the device 10 may be arranged to
release oxygen at a rate that is regulated in accord-
ance with the rate of carbon-dioxide absorption or,
more simply, may be pre-set to release oxygen at a
rate in accordance with the rate of carbon-dioxide
absorption expected. The pump 8 is operated con-
currently with the release of the oxygen; this is of
advantage in that it ensures that there is carbon-
dioxide removal even if the monitor device 7 fails.
The devices 7, 8, 9 and 10 are operated electric-
ally via the unit 6, electrical supply being drawn via
a switch 11 from a rechargeable battery 12 provided in
the equipment 3. The switch 11 is mounted in a pro-
minent position and is required to be switched from
its normal OFF position to its ON position to activate
the equipment 3 in its life-supporting function. Some
clear indication of the location of the switch 11 and
instruction for its operation are provided; in this
respect continuous illumination of the switch 11 and
- 15 an instruction panel (not shown) are provided in order
to ensure that any trapped occupant can readily
activate the equipment 3. One or more electrical
lamps 13 powered from the battery 12 via the switch 11,
provide more general illumination.
The equipment 3 may include facilities for enabling
communication to be established to the outside of the
vault, together with a tape player to provide pre-
recorded messages; such messages may be simply by way
of reassurance or may be more general and include
instructions for operation of the equipment and
survival or other procedures.
Although the equipment 3 described incorporates
one or more oxygen cylinders 5, these may be replaced
by cylinders of compressed air. However use of oxygen
is preferred, more especially because fewer cylinders
are generally needed to meet any specific survival
requirement. Such requirement might typically be for
survival for 100 person-hours over and beyond that
provided by the initial fresh-air atmosphere of the
enclosure. This can normally be met using two small
oxygen cylinders, whereas seven cylinders of comparable
size would be required if compressed air were to be
used.
The carbon-dioxide content of the atmosphere
within the enclosure 1 is desirably maintained below
3% and the oxygen content substantially within the
range of 17 to 19%.
