Note: Descriptions are shown in the official language in which they were submitted.
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OVERFLOW CONTROLLER
Technical Field
The present invention relates generally to an
overflow controller for detecting and preventing the
overfilling of a receptacle, more particularly to a
method and means for preventing the overflow of a toilet.
Backqround of the Invention
Overflow controllers, sometimes called flooding
disablers, are used to prevent fluid filled receptacles
from overfilling. For example, toilets are supplied with
fresh water to carry waste through a drain. If the waste
drain is plugged or restricted, it is important to
disable the fluid supply stream before the toilet reaches
overflow levels. This can particularly be a problem when
toilets are used in institutions such as prisons, where
inmates may intentionally plug the toilets to create
overflow conditions.
Various devices have been used to prevent the
accidental or deliberate ~looding of receptacles such as
toilets. In Barnum et al., U.S. Patents Nos. 4,538,30
and 4,498,203, for example, a sensor detects flood
conditions and prevents further introduction of sunply
fluid. The operation of these devices depends on the
creation of a partial vacuum in the fluid lines. An
orifice communicates with the fluid receptacle and short
circuits any partial vacuum communicated to it. When the
fluid level in the receptacle reaches sufficient height,
it partially seals the orifice thus preventing the
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release or short circuiting of the partial vacuum. The
partial vacuum then acts upon a lock-out mechanism to
block further flow of the supply fluid into the
receptacle. Although this system works well in many
situations, it would be advantageous to avoid reliance on
the creation of vacuum in the system.
In Albertson, U.S. Patent No. 3,928,874, an
overflow prevention device includes a float element
pivotably mounted in the toilet bowl. If the water in
the toilet bowl rises to a sufficient height, the float
is pivoted, activating a switch electrically conn~cted to
a solenoid that prevents operation of the handle
assembly. Alternatively, the switch is connected to
solenoid driven shut off valves located either in the
supply line or at the water closet outlet. The primary
disadvantage of this system is that it uses a pivoting
float mounted within the toilet bowl. The float can
easily be manipulated by an individual trying to create
fluid overflow. Additionally, such a float is subject to
corrosion or accretion of restricting material at its
pivot point.
In Gunther, U.S. Patent No. 3,185,789, a fluid
overflow switch apparatus is disclosed. The switch is
mounted in communication with the drain pipe or fluid
exhaust line so, when fluid in the drain pipe backs up,
the switch prevents further introduction of supply fluid.
In this apparatus, a float is connected to a float shaft
which slides through openings in a casing. When fluid
fills the casing, the float rises driving the float sha.t
against a switch operator. This action opens the circuit
to the washing machine and terminates the operation of
the machine. This system is disadvantageous both because
the sensor is located on the exhaust line and beca~se the
float and float shaft assembly are relatively
complicated.
In Meacham et al., U.S. Patent No. 5,028,910,
drain overflow alarm for a washing machine is disclosed
which sounds an alarm and shuts off the machine when
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water flow through the drain line is restricted. A float
switch is mounted in a vertical drain line attached to a
vertical stand pipe or fixed drain line. When the waste
water cannot freely drain away, water rises into the
float switch causing the float to rise and urge moveable
contacts into engagement with fixed contacts. This
triggers an alarm and shuts off the washing machine.
Alternatively, the float may include an internal magnet
which cooperates with a magnetic reed-type switch to
energize the alarm. This apparatus, however, must be
used on the drain line side of the receptacle and would
not work well with a receptacle such as a toilet where
fluid flow to the drain line may be completely blocked.
In Laverty, Jr., U.S. Patent No. 4,709,427 a
water level sensor prevents actuation of a fluid supply
valve when the toilet reaches overflow conditions. A
float is connected to a plunger rod which, during
overflow conditions, unseats a sealing piston allowing
fluid to flow through lines into a drain. This prevents
water pressure build-up in a piston actuator assembly so
that the valve cannot open to allow fresh supply fluid to
flow to the toilet. This device is a mechanically
actuated device which is subject to corrosion and
clogging that can affect its ability to function.
Other receptacle overflow prevention or warning
devices are disclosed in Morris et al., U.S. Patent Nos.
4,195,374 and 4,203,173 and in Applin, U.S. Patent No.
3,849,771.
The present invention overcomes various
drawbacks of the prior art devices discussed above.
Summary of the Invention
An overflow controller according to the
invention detects an overfill condition in an open
receptacle receiving fluid from a source and prevents
overfill by controlling the flow into the receptacle.
The fluid receiving receptacle has a desired maximum fill
level and a fluid inlet port for admitting fluid to that
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20g~332
point. A detector assembly is disposed in fluid
communication with the interior of the receptacle and
includes a vertical-overflow chamber into which fluid may
flow from the receptacle. The distal end of the overflow
chamber is positioned above the desired maximum fill
level. A buoyant float in the overflow chamber is
disposed for movement therein in response to any fluid
admitted thereto. A proximity detector, located above
the float, is adjustably mounted in the overflow chamber
and is operable to generate an output when an overfill
condition occurs and the f]oat reaches a threshold or set
point position. Additionally, the set point position may
be changed by adjusting the position of the detector to
detect the overfill condition at different levels.
Preferably, the proximity detector is a magnetic sensor,
and a permanent magnet is supported by the float, e.g.
embedded in its top section. A controller in the flow
line of the source is in operative communication with the
detector assembly and halts fluid flow to the inlet port
in response to the output from the magnetic sensor.
Brief Description of the Drawinqs
The invention will hereafter be described with
reference to the accompanying drawing, wherein like
numerals denote like elements, and:
Figure 1 is a side view of a plumbing fixture
that incorporates the overf 1GW controller of the present
invention;
Figure 2 is a partially cut-away perspective
view of the detector assembly connected to a receptacle;
and
Figure 3 is a cross-sectional view of the
detector assembly connected to a receptacle having an
annular chamber.
Detailed Description of the Preferred Embodiment
Referring to Figure 1, an overflow controller,
designated generally as 10, detects an overfill condition
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in an open receptacle 12 which receives fluid from a
source 14. Overflow controller 10 prevents overflow of
receptacle 12 by controlling the fluid flow from source
14. Open receptacle 12 may be of a variety of
configurations, but it will be shown and described as a
toilet for illustrative purposes.
Receptacle 12 is defined overall by a fluid
receiving bowl 16, having a fluid exit port 18 and a
fluid inlet port 20. Port 18 is located in the lower
interior region of bowl 16 and permits fluid in bowl 16
to be flushed from it. The fluid inlet port 20 is
preferably located proximate an open top 22 of bowl 16
and permits fresh fluid to flow into bowl 16 from source
14.
Intermediate fluid inlet port 20 and bowl 16 is
an annular chamber 24 into which fluid from source 14 is
admitted and from which the fluid flows into bowl 16.
Annular chamber 24 is disposed along the perimeter of
open top 22 and is fully enclosed except for a series of
apertures 26 disposed along the bottom of annular chamber
24 to allow fluid flow into bowl 16. The collective
cross-sectional area of apertures 26 must be sufficient
to permit flow into bowl 16 under steady-state conditions
without appreciable accumulation of fluid in annular
chamber 24. Steady-state conditions occur when fluid is
flowing into annular chamber 24 through fluid inlet port
20 at the normal maximum flow rate. In other words, the
cross-sectional area of apertures 26, whether formed as a
single slot through which fluid flows or a plurality of
individual apertures, must be large enough so that fluid
flows into bowl 16 at a rate substantially comparable to
the rate at which fluid flows through fluid inlet port 20
into annular chamber 24.
Overflow controller ~0 also includes a detector
assembly 28 disposed in fluid communication with the
interior of annular chamber 24. If the fluid level in
annular chamber 24 rises above a predetermined level,
detector assembly 28 provides an output to a controller
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30 disposed in a flow line 32 through which fluid flows
to fluid inlet port 20. Upon receiving the output from
detector assembly 28, controller 30 halts the fluid flow
to fluid inlet port 20 preventing receptacle 12 from
overfilling beyond that predetermined level. Controller
30 is preferably a solenoid controlled valve such as the
Burket Contromatic Corp. Model 281 valve.
As illustrated in greater detail in Figures 2
and 3, detector assembly 28 is disposed in fluid
communication with the interior of receptacle 12, and
preferably with the interior of annular chamber 24,
through an opening 34 in an outer wall 36 of receptacle
12. Detector assembly 28 includes a vertical overflow
chamber 38 into which fluid may flow from annular chamber
24 through opening 34. Vertical overflow chamber 38
includes a lower proximal end 39 and an upper or distal
end 40 positioned above the predetermined maximum fill
level illustrated as 41 in Figure 3. A buoyant float 42
independently disposed within chamber 38 is freely able
to move in response to any fluid admitted into that
chamber. Under normal, steady-state flow conditions,
when fluid is flowing down into bowl 16 from annular
chamber 24 at substantially the same rate as fluid is
entering annular chamber 34 from fluid inlet port 20,
float 42 is disposed in the lowermost portion of vertical
overflow chamber 38.
A proximity detector 46 is adjustably mounted
and preferably sealed in overflow chamber 38 above the
steady-state location of float 42. However, proximity
detector 46 is operable to generate an output when an
overfill condition occurs and float 42 rises to a
threshold or set point position in vertical overflow
chamber 38 at or prior to contact with proximity detector
46. As stated above, controller 30 responds to this
output to halt further fluid flow to fluid inlet port 20.
Proximity detector 46 may use different non-
contact technologies to detect float 42 when it moves
sufficiently close to detector 46. For example,
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proximity detector 46 may use a light sensor which
detects the float when a beam of light is interrupted.
Infrared, optoelectronic, magnetic and other types of
sensors may also be used to detect the proximity of float
42 preferably prior to contact with detector 46. In the
preferred embodiment, proximity detector 46 is a magnetic
sensor and float 42 includes a permanent magnet 44
supported in a top portion of the float.
Detector assembly 28 may be constructed in a
variety of configurations to achieve the goal of
detecting and preventing an overflow condition, but it is
preferably constructed from simple non-magnetic
components. In the illustrated embodiment, vertical
overflow chamber 38 includes a base unit 48 having a
horizontally extending nipple 50 which can be press fit
into opening 34 and sealed to prevent leakage of fluid
from open receptacle 12. A cavity 52 is disposed within
base unit 48 and extends through the interior of nipple
50. Cavity 52 fills with fluid when the fluid level in
open receptacle 12 rises above opening 34. Vertical
overflow chamber 38 also includes a vertical column 54,
preferably cylindrical, having an internal vertical
passage 56 extending therethrough. Vertical column 54 is
press-fit into an upper opening 58 of base unit 48 and
sealed with an appropriately sized O-ring 60. Vertical
passage 56 communicates with cavity 52 allowing the fluid
level in passage 56 to rise coincident with the fluid
level in open receptacle 12. Any air trapped in passage
56 by the rising fluid may escape through a pair of
pressure relief orifices 62.
Buoyant float 42 is preferably cylindrical in
shape and appropriately sized for full vertical movement
within vertical passage 56. Magnet 44 is embedded in the
top end of buoyant float 42 and is preferably an IG Incor
18 permanent magnet. Float 42 is comprised of a low
density plastic which is freely buoyed by fluid filling
vertical passage 56. One advantage of using independent
buoyant float 42 within vertical overflow chamber 38 is
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that no linkages are required to hold the float or
control its movement. Any time linkages are connected to
a float, the potential exists for corrosion to develop on
the linkages inhibiting the free movement of the float
and debilitating the function of the device.
The magnetic sensor 46 of detector assembly 28
is preferably contained in a plug 64 adjustably mounted
in the upper portion of vertical overflow chamber 38 to
allow adjustment of the threshold or set point position
at which sensor 46 is activated by magnet 44. This, in
turn, allows adjustment of the maximum desired fill level
41. As shown in the illustrated embodiment, plug 64
includes external threads 66 that are adjustably engaged
with internal threads 68 disposed in vertical passage 56.
Plug 64 further includes a hollow interior region 70 open
at the top and sealed at the bottom by a generally
horizontal wall 72. Magnetic sensor 46 is positioned in
hollow interior region 70 and hermetically sealed by an
appropriate potting compound within plug 64 in proximity
to wall 72. Horizontal wall 72 may also include a slot
for receiving magnetic sensor 46 and holding it in
position. Preferably, magnetic sensor 46 is a
magnetically operated low gauss digital position sensor
such as SS22PE manufactured by MICR0 SWITCH, but other
sensors, such as a Hall sensor or Permalloy sensor, could
also be used.
As buoyant float 42 and magnet 44 are buoyed
vertically, magnetic sensor 46 will provide an output
once magnet 44 reaches a threshold level which
corresponds to the desired fill level of open receptacle
12. The output is received by a conventional digital
control circuit 74 (Figure 1) which appropriately
modifies the output to cause controller 30 to halt any
further fluid flow to fluid inlet port 20. In the
preferred embodiment, electric current to the Burket
Model 281 flUsh valve is interrupted so that its spring-
loaded solenoid closes the valve preventing any fl~rther
fluid flow through the valve.
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If open receptacle 12 is a conventional toilet,
detector assembly 28 will also prevent flushing of the
toilet if flood conditions already exist. For example,
flushing of the toilet would normally be initiated by
pressing a plunger type switch 76, such as the solid-
state switch No. VX80-Cl manufactured by MICR0 SWITCH,
connected to digital control circuit 74. However if open
receptacle (toilet) 12 is already filled beyond the
desired fill level, magnetic sensor 46 will provide an
appropriate output to control circuit 74 to prevent
controller 30 from allowing any fluid to flow to inlet
port 20.
It will be understood that the foregoing
description is of a preferred exemplary embodiment of
this invention, and the invention is not limited to the
specific form shown. For example, various magnetic
sensors and control circuits may be used. The detector
assembly may be used in conjunction with receptacles
whether or not they have enclosed rims along their top.
In some situations, the detector assembly may be placed
directly within the fluid receptacle rather than external
to the receptacle. Additionally, the detector assembly
is not limited to the use of magnetic fields and magnetic
field sensors. It may also be designed to function with
infrared, optoelectronic, or other non-contact
technologies. These and other modifications may be made
in the design and arrangement of the elements without
departing from the scope of the invention as expressed in
the appended claims.
