Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02915710 2015-12-22
SYSTEM FOR SIMULATING GAS LEAKS
FIELD
100011 This invention relates to a system for simulating gas leaks. In
particular, this invention
relates to a system for simulating gas leaks of variable levels of gas.
BACKGROUND
100021 In many parts of the world, natural gas is supplied to houses and other
buildings to be
used for applications including, among others, ovens, and heating and cooling.
The gas is
typically delivered from gas suppliers through a network of pipes to the
ultimate user.
Unfortunately, gas leaks occur in the supply of natural gas, which is
dangerous as gas leak may
lead to explosions or other harm. The severity of a gas leak may depend on the
location of the
leak and the concentration and volume of gas escaping. It is, therefore,
important to be able to
quickly and accurately identify and analyze gas leaks as they occur to
minimize the potential
consequences associated with the release of natural gas. Proper training on
the identification and
analysis of gas leaks is critical in this regard.
100031 Training systems are known in the art for simulating gas leaks. These
prior art systems
attempt to train users how to identify gas leaks by releasing gas in a
controlled setting, which the
user may identify and analyze with a probe or other similar device. These
systems typically use a
0.5 inch pipe to release gas at a constant concentration and volume into the
atmosphere in a
controlled setting. The gas flow within the pipe is turned on and off with a
hand valve. The prior
art systems are therefore limited in the number and variety of "real world"
gas leak scenarios that
may be simulated.
BRIEF DESCRIPTION OF THE DRAWINGS
100041 In drawings which illustrate embodiments by way of example only,
100051 Figure 1 is a side view of an embodiment of the present invention
having a gas source
and a gas leak detection location that is a pipe.
100061 Figure 2 is a side view of an embodiment of the present invention
having a gas source
and a gas leak detection location that is a catch basin.
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100071 Figure 3 is a side view of an embodiment of the present invention
having a gas source, an
air source, and a gas leak detection location that is a manhole.
100081 Figure 4 is a side view of an embodiment of the present invention
having a gas source, an
air source, and a gas leak detection location that is a pipe.
100091 Figure 5 is a side view of an embodiment of the present invention
having multiple gas
pipes.
100101 Figure 6 is a plan view of a streetscape.
100111 Figure 7 is a plan view of a streetscape with a plurality of gas leak
detection locations.
100121 Figure 8 is another plan view of a streetscape with a plurality of gas
leak detection
locations.
100131 Figure 9 is a plan view of a test house with a plurality of gas leak
detection locations.
100141 Figure 10 is a plan view of the streetscape of Figure 6 divided into
zones.
DETAILED DESCRIPTION
100151 Referring to Figure 1, a system for simulating gas leaks 1 is
illustrated. A gas supply 10
is connected to supply a gas leak detection location 20 via a gas pipe 25. A
manual shut off valve
12 is located between the gas supply 10 and the gas leak detection location 20
for safety
purposes.
[00161 The system preferably includes a flow restrictor 27 sized to constrain
a maximum flow
rate of the gas from the gas supply 10. In an aspect the gas pipe 25 may
similarly be sized to
limit a flow of gas from the gas supply 10. In an aspect, the gas pipe 25 has
a diameter of
approximately 0.5 inches, for instance.
100171 A gas valve 15 on the gas pipe 25 controls the flow of gas between the
gas supply 10 and
the gas leak detection location 20. Preferably, the gas from the gas supply
includes an odorant to
assist in detection.
100181 The system 1 further provides a controller 30 which adjusts a gas set
point of the gas
valve 15 to control a flow rate of gas escaping at the gas leak detection
location 20.
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100191 In the embodiment of Figure I, the gas leak detection location 20 is a
pipe having a pipe
opening 22. In another embodiment, shown in Figure 2, the gas leak detection
location 20 is a
simulated manhole having a manhole cover 20. Manhole cover holes 24 provide
egress for the
gas been leaked through the output of the gas pipe 25. Other types of gas leak
constructs may be
used, for example a catch basin, drain, or other streetscape structure may be
simulated using a
similar arrangement to the embodiments of Figure I or Figure 2.
100201 Referring to Figure 3, in another embodiment, an air supply 40 is
further provided. The
air supply 40 is connected to the gas leak detection location 20 via an air
pipe 50. An air supply
valve 45 controls the flow of compressed air between the air supply 40 and the
gas leak detection
location 20. In the embodiment of Figure 3, the gas leak detection location 20
is a manhole. An
air manual shut off valve 42 is located on the air pipe 50 between the air
supply valve 45 and the
air supply 40. The controller 30 also adjusts the air set point of the air
supply valve 45 to control
the flow rate of air escaping at the gas leak detection location 20.
100211 The embodiment of Figure 3 further comprises a mixing chamber 60 below
the gas leak
detection location 20. Air entering the mixing chamber 60 from the air pipe 50
mixes with gas
that enters the mixing chamber 60 from the gas pipe 25. After the gas and air
is mixed, the
combined gas and air exits the gas leak detection location 20. The mixing
chamber 60 allows for
a high concentration of gas within a relatively small volume, thus minimizing
the amount of gas
needed to simulate a gas leak.
100221 In the embodiment of Figure 3, the mixing chamber 60 is within the
manhole 20 below
the manhole cover 26. In the embodiment of Figure 4, the gas leak detection
location 20 is a pipe
and the mixing chamber 60 is within the pipe 20 before the pipe opening 22. In
another
embodiment the gas leak detection location 20 is a catch basin and the mixing
chamber 60 is
within the catch basin 20 below the catch basin cover.
100231 In the embodiments shown in Figures 1 and 4, in which the gas leak
detection location 20
is a pipe, a flame arrestor may be placed at the end of the pipe to minimize
flames.
100241 In use, the gas leak detection location 20 is in communication with the
atmosphere. For
example, the gas pipe 25 and air pipe 50 are below ground and the gas leak
detection location 20,
for example a pipe, is open to the atmosphere via the pipe opening 22. Gas
from the gas supply
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and air from the air supply 40 are well-mixed at safe levels in the mixing
chamber 60. The
mixed air and gas then exits the system 1 through the gas leak detection
location 20. The exited
gas may then be detected using a combustible gas indicator known in the art.
100251 Various gas leak detection locations 20 may be used to simulate various
leak scenarios.
For instance, a pipe may be used to simulate a ground leak at a specific
location. A manhole or
catch basin may be used as detection locations 20 so simulate scenarios in
which an underground
leak has occurred and the gas has travelled underground from the initial
location of the leak and
is escaping into the atmosphere from the detection location 20.
100261 The concentration of air and gas is escaping the gas leak detection
location 20 may be
varied or turned on or off using the controller 30 to simulate various gas
leak scenarios and/or to
turn on or off the leak. The variances in concentration of air and gas may be
controlled and
monitored wirelessly and remotely, for example by using a programmable logic
controller.
Furthermore, a mobile device known in the art, such as a tablet computer 80
(shown in Figure
10) or a smartphone, may be used to control the programmable logic controller.
Further,
variances in concentration of air and gas may be made as the system is in use
or the variances
may be pre-programed and fully automated using the controller 30.
100271 In another embodiment, the system may have a plurality of gas leak
detection locations
20. For example, in the embodiment shown in Figure 5 there is a plurality of
gas leak detection
locations 20. Each gas leak detection location 20 is connected to a gas
manifold 70 by a gas pipe
25. The gas manifold 70 is in communication with the gas source 10. Each gas
pipe 25 has a gas
valve 15 to control the flow of gas between the gas supply 10 and each gas
leak detection
location 20. The controller 30 adjusts gas set points of each gas valves 15.
Thus, the amount of
gas escape each gas leak detection location 20 may be independently adjusted.
100281 In an embodiment of the system having a plurality of gas leak detection
locations 20,
compressed air may further be provided to one or more of the gas leak
detection locations 20 in
manner discussed above and shown in Figures 3 and 4. There may further be an
air manifold
connecting the air pipes 50 to the air supply 40.
100291 Referring to Figures 6-11, the system 1 may be used for training
purposes to simulate
various gas leak scenarios. The system I may be used within a mock-up
environment 98 to
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simulate real life gas leaks, for example a mock-up streetscape 98 as shown in
Figures 6-11. In
the illustrated embodiment, the mock-up environment 98 is a streetscape of an
urban community
with full sized roads and scaled-down buildings. The environment 98 preferably
represents
residential, commercial, and small industrial districts with typical utility
connections.
100301 Figure 6 shows an example of streetscape 98 without the gas leak
detection locations 20
illustrated. The streetscape 98 of Figure 6 shows a street 100, a test house
102, a classroom 104,
a condominium 108, and a trench 112.
100311 Figures 7 and 8 shows portions of a streetscape 98 having multiple gas
leak detection
locations 20. The gas leaks detection locations 20 may be placed in various
locations throughout
the streetscape 98. For example, in the embodiment of Figure 7, gas leaks
points 20 are
positioned under the street 100, and in the vicinity of the test house 102,
prop houses 104 and
classroom 104. In the embodiment of Figure 8, gas leaks detection locations 20
are positioned
under the street 100, and in the vicinity of a test house 102, prop houses
104, a condominium
108, and a sandbox 110. The gas leak detection locations 20 may further be
located within
buildings, for example within a test house as show in Figure 9.
100321 In use, a user may go to different locations within the streetscape 98
and test the gas
mixture exiting the gas leak detection locations 20 that the user encounters.
The types of gas leak
detection locations 20 and the concentration and volume of gas escaping the
gas leak detection
locations 20 may be varied during or between training exercises such that the
streetscape 98
simulates a variety of gas leak scenarios that could be encountered in real
life scenarios. The
person skilled in the art will appreciate that the system may be also be used
with a single leak
detection location 20 within the mock-up environment 98.
100331 As an example of how the system I may be used, using the streetscape 98
shown in
Figure 7, in a training exercise, a user, for example a trainee, could first
visit the gas leak
detection location 20 in the test house 102, determine the gas levels in the
house 102, exit onto
the street 100, determine the gas levels of the gas leak detection locations
20, and then enter the
classroom 104 to determine the gas levels there. As the exercise is being
conducted, a second
user, for example a training instructor, can turn off or on or change the
concentration of gas
escaping some or all of the gas leak detection locations 20 using the tablet
80, or other mobile
device.
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100341 As a further example, upon completion of a particular training
exercise, the instructor can
turn off or on or change the concentration of gas escaping some or all of the
gas leak detection
locations 20 using the tablet 80, or other mobile device, such that trainees
are faced with
different scenarios when entering the environment 98 next.
100351 The mock-up environment 98 may further be divided in multiple zones
120, for example
four zones 120 as depicted in Figure 10. Within each zone 120, one or more gas
leak detection
locations 20 may be located. Various arrangements of the style and location of
the gas leak
detection locations 20 may be used in the zones 120, providing different
training experiences
within each zone 120. For example, the zones 120 may be identical such that
the same training
exercise can take place at multiple locations at once. In another example, the
zones 120 may be
different from one another such that each zone 120 presents a different
training scenario. The
zones 120 may be different from one another in a number of ways, for example
in the elements
of the mock up environment 98, or by having more or fewer gas leak detection
locations, of by
having differences in the severity of the gas leaks.
100361 Various embodiments of the present invention having been thus described
in detail by
way of example, it will be apparent to those skilled in the art that
variations and modifications
may be made without departing from the invention. The invention includes all
such variations
and modifications as fall within the scope of the appended claims.
