Note: Descriptions are shown in the official language in which they were submitted.
533
This invention yenerally relates to an electrically operated
alarm which uses conductive fluid activated sensors to detect
the presence oE a conductive fluid in an open area to trigger an
audio and visual alarm.
B GROUND OF T~E INVENTION
Many people have had the said experience of having their basement
or part of their business or commercial facilities flooded
(usually by water), often with significant damage. The causes of
such misfortune are numerous: faulty washing machine, faulty
water tank, broken pipes, broken city water main, torrential
rain, failure of a sump pump, spring melt down, river overflow,
etc. Quite often measures could have been taken to eliminate the
cause or least to minimize the damages. The flood alarm system
described herein is a battery lor power adaptor) operated device
which uses conduc-tive fluid activated sensors to trigger a
visual and audio alarm. The device can also be used to transmit
the alarm to a remote position or/and to another alarm such as a
cable monitored burglar alarm. This alarm will inform the user
of the flood alarm system that a conductive fluid is present in
the position of one or more of the sensors. The user could then
immediately initiate corrective action to stop the cause of the
flooding and minimize damage. The device is simple, easy to
install and inexpensive. It would thus be available to tne
public at large. It would see use in residential and commercial
buildings to warn the occupants of flooding and could see
numerous secondary applications such as in small boats to
indicate that the water level has reached a given point, or to
indicate that a septic tank ls full.
Q~
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There are a number o~ patented devices using the principle of
fluid conductivity to close a circuit between two exposed
electrodes. Most of the devices are intended to indicate the
level of a given fluid, the presence of impurities in a fluid, a
change in Eluid density, etc. Most of the patented devices are
designed to operate in some form of container in mechanical,
chemical and other processes. These prior devices are generally
unsuitable to detect the presence of fluids in open spaces such
as the basement of a house. Furthermore, most of these devices
use standard electrical power to operate. ~his can prove
inconvenient in the case of a power failure which cause such
devices to fail to operate, a problem commonly encountered with
other electrically powered devices such as sump pumps.
In accordance with the present invention, there is provided an
inexpensive and easy to install alarm device effective to warn
that flooding has begun in the location monitored. In response
to the warning, action can be taken immediately by the user to
minimize the hardships, damage and the insurance claims normally
associated with Elooding.
In accordance with one aspect of the present invention there is
provided a sensor means for detecting the presence of conductive
fluid in an open area comprising an electrically conductive
pair, at least one pair of exposed electrodes in closely spaced
relation, each of said electrodes connected to a different
conductor of said conductive pair, at least one cover means, each
cover means enclosing one pair of said electrodes, said cover
means including at least one opening to allow ingress of
conductive fluid into said cover means.
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In accordance with another aspect of the invention, there is
provided a flood alarm system comprising a power supply, at
least one detection circuit and an alarm circuit, each of said
detection circuits connected between the first and second
terminals of said power supply and comprising in series an
indicator means and a sensor means responsive to the presence of
conductive fluid to close a current path through said detection
circuit and enable said indicator means, said alarm circuit
connected between the first and second terminals of said power
supply and comprising in series an alarm means and a driver
means, said driver means connected to each of said detection
circuits for deriving a source of bias voltage when any one of
said detection circuits is closed, said sensor means comprising
an electrically conductive pair, at least one pair of exposed
electrodes in closely spaced relation, each of said electrodes
connected to a different conductor of said conductive pair, at
least one cover means, each cover means enclosing one pair of
said electrodes, said cover means including at least one opening
to allow ingress of conductive fluid into said cover means.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate embodiments of the invention:
Figure 1 is a schematic representation of the main flood alarm
system components.
Figure 2 is a perspective drawing showing details of a first
conductive fluid sensor means.
Figure 3 is a perspective drawing showing details of a second
conductive fluid sensor means.
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Figure 4 is a drawing of a conductive fluid sensor Means having
five exposed electrode pairs.
Figure 5 is a circuit diagram of the flood alarm system circuit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The general layout of the main components of the flood alarm
system is shown in Figure 1. The flood detector unit can be
connected to an alternate battery power source to ensure
operation when electrical service fails. Point and area sensors
are connected to the flood detector unit and are placed by the
user in the open area in which the presence of water or other
conductive fluid is to be monitored, such as for example in a
basement. When one or more of the sensors are placed in contact
with water or other conductive fluid, an alarm circuit is made
in the flood detector unit soundiny an audible alarm. A remote
buzzer can be used to alert the user at a location remote from
the flood detector unit, such as for example in an upstairs
bedroom. Upon being alerted, the user would go to the location
of the flood detector unit and inspect the indicator lights
located on the flood detector unit which indicate which of the
sensors are in contact with water or other conductive fluid.
Knowing the location of the floodin~, the user can then take
remedial action. The flood detector can also be connected to a
remote alarm system, such as for example a cable connected
subscription security system to enable flood monitoring to be
carried out in the user's absence.
The basic circuit of the flood alarm system is depicted in
Figure 5. Power is applied at points A and B by an external
power source such as a 9 vo:lt AC/DC adaptor. Back up battery C
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operates in conjunction with diodes D to provide power in case
of failure of the external power source. Four sirnilar detection
circuits are shown connected in parallel between power supply
terminals A and B. Each detection circuit includes normally
closed manual switch E, indicator light F and a conductive fluid
sensor having at least one exposed electrode pair. For
illustration, the four detection circuits shown in Figure 5 each
have one of exposed electrode pairs OP, QR, ST and UV. When a
conductive fluid such as water bridges the gap between electrodes
O and P, for example, a current path through the indicator
circuit is closed. The flow of current causes indicator light F
to glow indicating which conductive fluid sensor is in the
presence of conductive fluid. The indicator light F is preferably
a light emitting diode. Because light emitting diodes require
very little current to operate, they can be enabled by the small
current which typically passes between exposed electrodes when
in the presence of water, a relatively poor conductor of
electricity.
The flood alarm system is also provided with an alarm circuit.
The alarm ci~cuit is connected between the power supply terminals
A and B and includes alarm buzzer I and transistor driver L.
When one or more of the detection circuits is closed due to
conductive fluid between one or more of the electrode pairs OP,
QR, ST and UV, a bias voltage is applied to the base of
transistor driver L through resistors M and N causing transistor
driver L to conduct, thereby sounding alarm buzzer I which
typically has a high current demand. Remote alarm buzzer J can
be connected in parallel with alarm buzzer I to sound an alarm
to a remote location. Remote alarm buzzer J allows the user to
position the flood detector unit in the basement and the remote
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alarm buzzer J in an office or a bedroom or a different floor.
In addition, a cable connected subscription security system
could be connected at point K. The cable connected system could
use the change in voltage at point K upon actuation of alarm
buzzer I to trigger the subscription alarm system.
When the alarm buzzer I is sounded, the user can inspect
indicator lights F to determine which conductive fluid sensor i5
in the presence of conductive fluid. The user can stop alarm
buzzer I by opening manual switch E thereby removing the bias
voltage from transistor driver L.
The flood alarm system circuit depicted in Figure 5 also includes
a test circuit comprising normally open manual switch G and test
indicator light H. Pressing switch G will activate test indicator
light H and will sound alarm buzzer I and, if connected, remote
buzzer J.
A conductive fluid sensor in accordance with the present
invention is shown in Figure ~. The sensor comprises an
electrically conductive pair, and a plurality of exposed
electrode pairs, each enclosed in a cover means. The cover means
2~ with its lid removed is shown in greater detail in Figures 2 and
3. The electrically conductive pairs comprise parallel conductive
wires encased in a unitary insulating jacket. The exposed
electrodes are formed by stripping a portion of unitary
insulating jacket thereby exposing adjacent portions of the
conductive wires. Non conductive spacers represented in Figure
in black are connected to or are formed integrally with the
cover means and serve to maintain the exposed electrodes in
closely spaced relation without touching. The cover means can be
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made of plastic or other suitable material and is provided with
one or more perforations to allow ingress of conductive fluid
into the cover means. The cover means protects each exposed
electrode pair from dirt, debris, damage and accidental touching.
When conductive fluid bridges the small gap between the exposed
electrodes, the wires of the electrically conductive pair are
placed in electrical communication allowing the conductive pair
to be used to trigger an indicator and/or alarm. The exposed
electrodes should be sufficiently long to allow adequate current
-to energize or enable the indicator or alarm.
The exposed electrodes shown in Figure 2 are particularly suited
to be used in the vertical position for detecting a rise in the
level of conductive fluid passed a given threshold. The ends of
the exposed electrodes are bent to be parallel with the surface
of the water body the height of which is being monitored.
Accordingly, as soon as the water level makes initial contact
with the hori~ontal portion of the bent electrodes, there is a
sufficiently large wetted areas to pass adequate current to
energize or enable the indicator or alarm.
- Although meant to serve as a flood alarm system for residential
and commerical buildings, the device could be also economically
used in many areas such as in sma~l ships to indicate that water
has reached a certain level by positioning the sensors
accordingly. It could also indicate the rise of any body of
water which might endanger installations. It could also indicate
the failure of a pump by placing a sensor at a point higher than
that at which the level of a fluid would have started the pump~
There are indeed numerous applications which would benefit the
public.
