Note: Descriptions are shown in the official language in which they were submitted.
2 1 ~ 5 ~J0 5
WATER LEAK DETECTING AND SHUT-OFF SYSTEM
FIELD OF THE INVENTION
This lnventlon relates to a system for detectlng and
mlnlmlzlng fluld leaks.
BACKGROUND OF THE INVENTION
Wherever water ls held under pressure, there ls the prospect
of a leak and conse~uent water damage. One source of such leaks
ls a household hot water tank. Another, 18 the water llnes
runnlng to a domestlc washlng machlne. Whlle leaks are not
fre~uent occurrences, a leak, lf not detected lmmedlately, can
cause conslderable property damage.
The sub~ect of the lnventlon addresses thls problem.
SUMMARY OF THE INVENTION
Accordlng to the present lnventlon, there ls provlded a
system for detectlng and mlnlmlzlng fluld leaks fed by a fluld
llne, comprlslng: a shut-off valve for lnterposltlon ln the fluld
llne; a valve controller for sald valve; at least one fluld
senslng probe for placement ln at least one leak susceptlble
area; sald valve controller operably assoclated wlth sald at
least one fluld senslng probe such that sald valve controller
acts to close sald valve when one of sald at least one fluld
senslng probe senses fluld.
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BRIEF DESCRIPTION OF THE DRAWING
In the flgures whlch lllustrate example embodlments of the
inventlons
flgure 1 ls a schematlc representatlon of a system made
ln accordance wlth the lnventlons; and
flgure 2 ls a schematlc representatlon of a portlon of
a system made ln accordance wlth another embodlment of the
lnventlon.
DETAILED DESCRIPTION OF THE PREFERRED E~BODIMENTS
Wlth reference to flgure 1, ln overvlew, a system 10 for
detectlng and mlnlmlzlng water leaks comprises a shut-off valve
12 lnterposed ln a water llne lllustrated ln phantom at 14. A
controller for the valve ls lndlcated at 16. The valve
controller 16 ls coupled to a power connecter 18 through a
network lndlcated generally at 20 whlch ls descrlbed more fully
herelnafter. The valve controller 16, and an alarm buzzer 28,
are operatlvely assoclated wlth water senslng probes 22 through
network 20.
Valve 12 ls a normally closed ~olenold valve. The valve
comprlses a valve body 30 connected to a solenold core 32 whlch
ls surrounded by a solenoid coil 34. The solenoid core 32, and
therefore the valve body 30, ls blased by spring 36 to a valve
closed positlon, as lllustrated in the flgure. The valve
controller 16 comprlses a magnetlc coll 40 and a relay swltch 42
blased by sprlng 44 to a flrst posltion whereat the blade 43 of
-- 2
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the relay contacts contact 42a, as lllustrated ln flgure 1. The
connector 18 comprlses a palr of connectors 46 for connectlon
with an alternatlng current source of power, such as a household
supply. Each probe 22 comprlses a palr 48a, 48b of proxlmate
open clrcuited wlres partlally surrounded by houslng 50. The
probes are connected ln parallel to contacts 52a, 52b of ~unctlon
52 of network 20.
Network 20 comprlses a power supply llne 56 and a ground
llne 58 coupled to connector 18 through transformer 60. A
rectlfler 62 ls posltloned ln the power supply llne and a
capacltor 64 brldges the power supply llne and the ground llne
58. The power supply llne 56 ls connected to (1) one slde of the
magnetlc coll 40 of valve controller 16, (11) contact 42b of
relay swltch 42, (111) one slde of alarm buzzer 28, and (lv)
contact 52a of ~unctlon 52. The power supply llne 56 has a path
to ground through zener breakdown dlode 66, reslstor 68, and
translstor 70 -- due to the connectlon to the collector of
translstor 70, wlth the emltter of the translstor 70 connected
dlrectly to ground.
The other slde of magnetlc coll 40 of valve controller 16
ls connected to ground through translstor 72 -- due to the
connectlon from thls other slde of the coll to the collector of
translstor 72, wlth the emltter of the translstor 72 grounded.
Alarm buzzer 28 has a connection to ground through translstor 74
-- due to the connectlon of the buzzer to the collector of the
translstor 74, wlth the emltter of translstor 74 grounded.
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Each of transistors 70, 72, and 74 are operated ln an on-off
swltchlng mode vla a control lnput to thelr base. The control
llne 77 to the base of translstor 70 extends from ~unctlon
termlnal 52b through reslstor 78. Further, a capacltor 80 and
a varlable reslstor 82 are connected ln parallel between llne 77
and ground. The control llne 80 to the base of translstor 72
extends dlrectly from the collector of translstor 70. The
control llne 83 to the base of translstor 74 extends from the
collector of translstor 72 through a reslstor 84.
Protectlon llne 86 extends between power supply llne 56 and
the collector of translstor 72 through zener dlode 88 and reverse
blased dlode 90.
In operatlon, probes 22 are posltloned ln areas whlch may
become wet lf a leak develops downstream of solenold valve 12 ln
water llne 14 (l.e. leak susceptible area~). For example, one
probe could be posltloned at the base of a washlng machlne fed
by llne 14 and another at the base of a domestlc hot water tank
fed by llne 14. A thlrd probe could be ~olned to the ~unctlon
52 and placed ln a basement storm sewer. Because of sprlng 36
whlch blases the solenold valve to the closed posltlon, prlor to
connector 18 belng plugged lnto a source of electrlcal power,
solenoid valve 12 keeps water llne 14 shut off.
In the following descrlptlon, it ls flrst assumed that
probes 22 are dry, such that wlres 48a, 48b of each are open
clrculted. Once connector 18 ls plugged lnto a source of
alternatlng current power, transformer 60 steps down the voltage
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and rectlfier 62 and capacitor 64 act to rectlfy the voltage and
regulate lt ln order to provlde a substantlally constant DC
voltage supply on llne 56. Wlth each of the probes dry, there
can be no slgnal on llne 77 to translstor 70, thus, thls
translstor ls "off". The DC voltage on line 56 breaks down zener
dlode 66 and, wlth translstor 70 off, applles a control voltage
on control llne 80 to the base of translstor 72. Thls turns
transistor 72 "on" such that it acts as a short clrcult. Wlth
transistor 72 acting as a short, a clrcuit path i8 completed from
power llne 56 through coll 40 of valve controller 16 to ground.
The resultlng current magnetlzes the coll to swltch relay 44 from
the posltlon shown ln the flgure to a posltlon whereat the blade
43 of the relay contacts contact 42b. Thls connects the solenold
coll 34 of valve 12 wlth the DC power llne thereby causlng the
solenold coll 34 to draw ln solenold core 32 agalnst the urglng
of sprlng 36 hence movlng the valve body 30 to a valve open
position.
It will be noted that wlth translstor 72 actlng as a short
clrcult, there ls no control slgnal on llne 83 and therefore
translstor 74 acts as an open clrcult. Thus, buzzer 28 ls cut
off from electrlcal power and so ls sllent.
If one of the probes 22 ls lmmersed ln water, then the
houslng 50 of the probe admlts water so that water surrounds
wlres 42a, 42b. Thls short-clrcults these wlres thereby
provldlng a path from the DC power llne 56 to the control llne
77 of translstor 70. The magnltude of the control slgnal on llne
77 can be ad~usted by approprlate ad~ustment of varlable reslstor
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82. Thls control slgnal turns translstor 70 "on" so that lt acts
as a short clrcult whlch ln effect grounds control llne 80 of
transistor 72. Wlth control llne 80 grounded, translstor 72,
whlch had been "on" and actlng as a short clrcult now turns "off"
and therefore acts as an open circult. Consequently, the end of
coll 40 ~olned to the collector of translstor 72 now has no path
to ground. Consequently, no slgnlflcant current flows through
coll 40 from the DC power supply llne 56 so that the blade of
relay 42 swltches lnto contact wlth contact 42a under the urglng
of sprlng 44. Thls, ln turn, deprlves the solenold valve 12 of
power whlch results ln the valve 12 shuttlng by vlrtue of the
urglng of sprlng 36.
Zener dlode 88 and reverse blased dlode 90 of protectlon
llne 86 protect translstors 72 and 74 from the back emf generated
when the current flowlng through coll 40 ls substantlally cut
off.
The open clrcultlng of translstor 72 results in a slgnal
voltage appearlng on llne 83 to translstor 74. Thls causes
translstor 74 to turn "on" and, therefore, swltch from an open
clrcult condltlon to a short clrcult condltlon whlch completes
a clrcult path from the power supply llne through buzzer 28 to
ground. Thls actlvates the buzzer to emlt an audlble warnlng.
The buzzer contlnues soundlng and the solenold valve 12 remalns
shut off for as long as the lmmersed probe 22 remalns ln contact
wlth water and system 10 remalns powered. If power ls lost at
any tlme, the buzzer wlll cease operatlon, but the solenold valve
wlll remaln shut off.
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Once the probe 22 whlch had been lmmersed ls drled, system
10 returns to a condltlon wlth the solenold valve open and the
buzzer 28 sllent.
Typlcally water llne 14 wlll be the water maln for a
bulldlng, however, ln clrcumstances where system 10 ls to protect
agalnst leaks only ln respect of one plece of equlpment, such as
a hot water tank, then llne 14 will be the water llne feedlng the
hot water tank.
Whlle probes 22 have been descrlbed as a palr of proxlmate
open clrculted wlres, lt wlll be appreclated that more
sophlstlcated probes may be used, such as humidlty sensors. In
such case, consequent changes would be requlred to network 20 as
wlll be understood by those skllled in the art. Whlle system 10
has been descrlbed ln assoclatlon wlth an alarm buzzer 28,
obvlously any other warnlng devlce may be employed. For example,
on translstor 74 short clrcultlng, a prompt could be glven to a
securlty system to phone a monltorlng company in order to apprlse
the monltorlng company of the alarm condltlon. As a further
modlflcatlon, a temperature sensor could be provlded whlch acts
to ground control llne 77 of translstor 70 and turn the
translstor "off" ln the event that the sensed temperature falls
below a preset level. Wlth control llne 77 grounded, the probes
22 are dlsabled. Thls would have utlllty where monltorlng was
only necessary lf the temperature exceeded a predetermlned
mlnlmum.
Wlth reference to flgure 2, whereln like parts have been
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glven llke reference numerals, system 100 comprises a probe 22a
whlch ls connected to contacts 152a and 152b of ~unctlon 152 and
probe 22b which l~ connected to contacts 152c and 152d of
~unctlon 152. Line 110a extends from contact 152a to one lnput
of AND gate 120 and llne 110b extends from contact 152b to the
other lnput of AND gate 120. A llne 56a ls connected between the
power supply llne 56 (of flgure 1~ and llne 110a. AND gate 120
outputs on llne 112 to one lnput of OR gate 140. An LED 114 ls
connected to llne 112. Slmilarly, llne 116a extends from contact
152c to one lnput of AND gate 130 and llne 116b extends from
contact 152d to the other lnput of AND gate 130. AND gate 130
outputs on llne 118 to the other lnput of OR gate 140. An LED
122 ls connected to llne 118. OR gate 140 outputs on control
llne 77 to translstor 70. The remalnder of system 100 ls
ldentlcal to system 10 of figure 1 and so ls not further
detalled.
In operatlon, wlth llne 56 powered, llnes 110a and 116
sustaln a "hlgh" slgnal whlch lnputs thelr respectlve AND gates
120, 130. If probe 22a ls emerged ln water, lt short clrcults
such that there ls then a "hlgh" slgnal on llne 110b to AND gate
120. Thls causes the output of AND gate 120 to go from "low" to
"hlgh". The hlgh output causes L~D 114 to lllumlnate. Thls hlgh
output also passes through OR gate 140 such that a control
voltage ls passed to control llne 77 of translstor 70. As
aforedescrlbed ln con~unctlon wlth flgure 1, thls causes the
solenold valve to shut off and the buzzer to sound. Slmllarly,
lf probe 22b ls lmmersed ln water, the output of AND gate 130
goes hlgh and thls hlgh slgnal turns on LED 122. The hlgh slgnal
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also passes through OR gate 140 to cause the solenold valve to
shut off and the buzzer to sound. It wlll be apparent that,
while the operation of system 100 ls slmilar to the operation of
system 10 ~of figure 1), the llghtlng of LED 114 and/or 122
provldes an lndlcatlon of which probe 22a, 22b ls lmmersed ln
water. Thls speeds locallzation of the leak. Obviously, the
system 100 of figure 2 may be modified to accommodate additional
probes, lf desired. An enhancement to the system of figure 2
would be to place addltlonal probes in areas whlch could become
wet for reasons other than a leak arlslng ln equipment fed by
water llne 14. For example, a probe could be placed at an area
of a bulldlng hlghly susceptlble to water damage (e.g. computer
equlpment) so that should the probe so placed sense water, an
alarm would be generated.
Whlle system 10 (of flgure 1) and 100 (of flgure 2~ have
been descrlbed in con~unctlon wlth probes for detectlng water,
lt wlll be apparent that the systems wlll work equally well lf
probes whlch sense the pressure of other flulds, such as natural
gas, are substltuted.
Other modlflcatlons wlll be apparent to those skllled ln the
art and, therefore, the lnvention ls deflned ln the clalms.
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