Note: Descriptions are shown in the official language in which they were submitted.
CA 02626031 2008-03-09
Title of the Invention
An integrated domestic utility system.
Cross-references to Related Applications
None.
Field of the Invention
This invention is related to the field of liquid separation and more
particularly relates to an integrated domestic utility system adapted to
recycle grey water for domestic uses such as flushing toiiets.
Background of the Invention
Water conservation is becoming increasingly important as the cost of
treating domestic water increases and sources of clean feedstock become
scarce. In most domestic households treated domestic water is used to
flush toilets. This is a waste of a valuable commodity. It also increases
the cost of sewage treatment charged to the home owner because the
municipal cost of sewage treatment is largely based on the amount of
domestic water consumed. Furthermore, solar energy is not effectively
used as a means to heat domestic water as it remains expensive to
purchase and install the components. Therefore, fresh cold water is sent
to the hot water heater requiring significant amounts of thermal energy
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to bring it to a desired temperature. Rainwater is a source of toilet flush
water that is often overlooked.
A number of attempts have been made to solve the problem of
conserving domestic water. For example, US Patent 4228006 "Domestic
Water System" issued to Hanna on October 14, 1980 discloses a system
whereby grey water from various in-home sources is directed to a
clarifier. Chlorine is added. The water is then reused for non-potable
applications. Hanna relies upon the addition of toxic chemicals and does
not utilize solar energy for heating. The use of rain water is over looked
by Hanna. In US Patent 5406657 "Water Recycling Device for i~iush Toilet
Use" issued to Donati on April 18, 1995 there is disclosed the use of grey
water to supply the toilet tank with flushing water. This system can be
retrofitted into existing domestic plumbing systems. The Donati system
relies upon an external pond to collect rain water. This source can
become easily contaminated and turbid and is not suitable for pumping
through domestic household pipes. Another example is found in US
Patent 6889395 "Flush Reservoir" issued to Hodges on May 10, 2005.
Hodges discloses a rain water collection system for toilet flushing.
However, no grey water is used.
Therefore, there continues to be a need for an integrated domestic utility
system that uses both grey water recycling and rainwater to satisfy
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demands for non-potabie water in a house, for example, toilet flushing.
There is a further need for an integrated domestic utility system that
takes advantage of available solar energy to maintain a readily available
source of grey water at a suitable temperature for indoor use.
Summary of the Invention
My Invention is an integrated domestic utility system comprising a
rainwater tank for collecting and storing a predetermined volume of
rainwater, a grey water tank for collecting and storing a predetermined
volume of grey water and a valve to regulate flow from the rainwater tank
to the grey water tanic. The invention further comprises a pump for
distributing a demand amount of grey water from grey water tank to at
least one toilet fixture storage tank for flushing. Solar heating is used to
maintain the stored grey water at a desired temperature. The rainwater is
collected from at least one rainwater collection point in fluid
communication with an at least one rainwater flush tank having debris
removal means and overflow means. The rainwater flush tank is
disposed hydrodynamically below the rainwater collection point. The
rainwater storage tank is disposed hydrodynamicaliy below the rainwater
flush tank and in fluid communication therewith, so that the rainwater
storage tank continues to receive a flow of rainwater from the rainwater
flush tank until it is full. Excess rainwater is directed to the overflow
means. The invention also comprises at least one grey water collection
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point such as a shower or bathtub that is in fluid communication with the
grey water storage tank.
In another example of the invention there is found programmable control
means for controlling operation of the system.
In one example of the Invention the pump is controlled by a pressure
switch designed to sense fluid pressure in the pump discharge conduit so
that when a toilet is flushed the pump starts and pumps water from the
grey water storage tank to replenish the toilet tank.
In yet another example of the invention a solar heating heat exchange
circuit Is used to maintain the grey water stored in the grey water tank at
a suitable temperature which can be predetermined. There may be a roof
mounted solar collector that transfers heat to a heat exchanger located in
the grey water storage tank. The heat exchanger is simple to fabricate
and so inexpensive to instail. The water temperature is controlled by
controlling the flow of heat transfer fluid from the solar collector to the
heat exchanger.
In one example of the invention a domestic hot water heater can be
added to the heat exchange circuit to pre-heaà domestic hot water
thereby saving energy.
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in another example of the invention there is provided an integrated
domestic utility system on a small scale for installation in a bathroom. It
collects and stores grey water using a bathtub. Grey water is pumped
from the bathtub to a nearby toilet flush tank by means of a pump. A
pressure switch senses fluid pressure in the pump discharge conduit so
that when the toilet is flushed the pump starts and pumps water from the
tub to the empty toilet tank. A controller senses when grey water in the
tub Is low and permits a supply of domestic water to replenish the supply
of bathtub water so that the toilet always has a source of flush water.
Objects and Advantages of the Invention
Several objects and advantages of the invention are:
a. to save domestic treated water by diverting it away from non-
potable uses;
b. to recycle and store grey water for non-potable uses;
c. to rely upon rain water to augment grey water storage;
d. to collect and store rain water for non-potable domestic use;
e. to reduce domestic sewage volumes by first recycling grey
water;
f. to rely upon solar energy to heat stored grey water to a suitable
temperature;
g. to augment domestic hot water heating using solar energy;
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h, to provide an integrated domestic water supply system that can
be installed in a home; and,
i. to provide a small scale integrated domestic water system that
can be installed in a bathroom for recycling grey water from a
bathtub.
Still further objects and advantages of my Invention will become apparent
from a consideration of the ensuing description and drawings.
Brief Description of the Drawings
Figure 1 is a schematic of one example of an integrated domestic utility
system.
Figure 2 is an illustration in side cross-sectional view of a self-regulating
valve between the rainwater storage tank and the grey water storage tank
of one example of the invention.
Figure 3 is a sectional illustration of a grey water storage tank of one
example of the invention.
Figure 4 is a collection of drawings of the heat exchanger within the grey
water storage tank of one example of the invention.
Figure 5 is a schematic of one example of a small scale integrated
domestic utility system suitable for installation in a bathroom.
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Detailed Description
Referring to Figure 1, the invention (10) is an integrated domestic utility
system comprising means for collecting a predetermined volume of
rainwater (12), means for storing the predetermined volume of rainwater
(14), means for collecting a predetermined volume of grey water (16),
means for storing the predetermined volume of grey water (18)x a self-
regulating valve (20) (Not illustrated in Figure 1. See Figure 3) disposed
between the means for storing the predetermined volume of rainwater
and the means for storing the predetermined volume of grey water, a
pump (22) for distributing a demand amount of grey water from the
means for storing the predetermined volume of grey water to an at least
one toilet fixture (24) storage tank (26) for flushing the toilet and means
(28) for maintaining the predetermined volume of grey water at a desired
temperature.
Still referring to Figure 1, means (12) for collecting a predetermined
volume of rainwater comprises an at least one rainwater collection point
(30). In the illustration, the rainwater collection point is a roof top (31)
trough (33) in fluid communication by way of conduit (32) with an at least
one rainwater flush tank (34) having debris removal means (inside the
flush tank and not illustrated but consisting of siphons and other devices
well known to remove floating or sinking debris) and overflow means
(36). The at least one rainwater flush tank (34) is disposed
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hydrodynamically below the at least one rainwater collection point (30) so
that water flows by gravity from the high point to the low point and no
powered devices are required.
in i"igure 1, means (14) for stor[ng the predetermined volume of
rainwater comprises a rainwater storage tank (38) having the
predetermined volume and disposed hydrodynamically below the at least
one rainwater flush tank (34) and in fluid communication by way of
conduit (40) with the rainwater flush tank. The rainwater storage tank
(38) continues to receive a flow of rainwater by way of conduit (40) from
the at least one rainwater flush tank (34) until full. Excess rainwater is
directed towards overflow means (36).
Still referring to Figure I, means (16) for cotlecting a predetermined
volume of grey water comprises at least one grey water collection point
(42). In Figure 1 the grey water collection point (42) is illustrated as a
shower stall but it could also be a bath tub. These points are chosen as
they represent the largest source of grey water which is relatively organic
matter free. Dishwater from a sink or dishwashing machine is not used
because it contains a large concentration of organic matter that can
become biologically active and contaminate the grey water collection and
storage system causing odors and health concerns. The grey water
collection point (42) is in fluid communication by way of conduit (44) with
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means (18} for storing the predetermined volume of grey water
comprising a grey water storage tank (46) having the predetermined
volume. The rainwater storage tank (38) is in fluid communication by
conduit (48) with the grey water storage tank (46) by way of the self
regufating valve (20) previously identified and more fully described
below. The grey water storage tank is disposed hydrodynamically below
the rainwater storage tank for gravity induced flow.
Now referring to Figures 1 and 2, there is shown a diagram of the self
regulating valve (20). The self regulating valve (20) is disposed within a
wall (50) of the grey water storage tank (46). The valve comprises an
intake conduit (52) in fluid communication by way of conduit (48) with
the rain water storage tank (38). Conduit (52) and conduit (48) are joined
by a suitable connector {70}. The valve inciudes an inlet orifice (54) for
discharging rain water into the grey water storage tank (46). The orifice
is sized so that the flow into the grey water tank is controtied at a
predetermined flow rate which is generally greater than the pump rate.
However, the pump is equipped with detectors that can sense when the
pump intake is dry due to depletion of all rain and grey water and then
the sys.tem's programmable controller (112) by way of control cable (117)
causes a solenoid controlled valve {i 13) to open causing an infusion of
domestic water Into the shower staii (42) draining into the grey water
tank to ensure that the pump suction does not go dry and that pump
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demand is always met. A compression seal flap (56) seals the inlet orifice
(54) in a locking relationship using a locking means (58). The
compression seal flap (56) is attached to a mounting member (59) having
a first end (61) and a second end (63). The first end (61) mounts a
rocking locking arm (65) at its mid point (67). The locking arm (65)
comprises a first end (69) having a locking hook (71) and a second end
(73) having a mounting hole (75), In operation, biased locking arm (65)
locking hook (71) engages a locking nub (77) disposed above orifice (54)
to keep the compression seal flap (56) tight against the orifice (54). The
second end (79) of mounting member (59) is pivotaEly attached at axis
(85) to member (81) mounted to wall (50) of the tank by mounting means
(83). The mounting member (59) is adapted for about 20 degree rotation
about axis (85) as water in the grey water tank moves up and down with
demand. Locking means (58) further includes a curved member (89)
having a first free end (91) adapted to abut the mounting member (59)
and a second free end (93). The inset shows that free end (91) is not
attached to mounting member (59) but moves up and down with the level
of water in the grey water tank. Member (89) has a curved slot (95)
adapted to accept a locking screw (97) on float arm (99) so that as the
float arm (99) moves up and down around axis (85) in response to water
level the curved member (89) rotates along with it. The locking screw (97)
allows adjustment of the sealing movement of the rnounting member (59)
in respect of the water fevel elevation. Attached to the end (101) of the
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float arm (99) is a water level float (60) adapted for floatation within the
grey water tank. The float is in mechanical communication with the
locking arm (65) by way of actuating member (105). The first end (107)
of the actuating member is fixed to the second end (73) of the locking
arm through mounting hole (75). The second end (109) of the actuating
member (1 05) is attached to the float arm (99) at a point 0 11) that
Induces sufficient leverage on the locking arm (65) so that It Is pulled
down by the actuating member thus releasing locking hook (71) from
locking nub (77). The compression seal flap (56) will disengage from the
orifice (54) with the mounting member (59) falling to rest on the end of
the curved member (89) permitting water flow from the rain water
storage tank (38) through the completely-opened orifice (54) into the
grey water storage tank. The valve {20) will thus periodically open
completely to ensure that the orifice may flush and so is kept free of
debris so that the compression seal can be absolute, thereby preventing
seepage of rainwater into the grey water tank over time. As the grey
water storage tank fills with rainwater in response to the release of the
locking arm, the partially-submerged float rises to a point where the
curved member free end (91) engages and pushes the mounting arm (59)
with compression seal (56) against the orifice (54) thereby closing the self
regulating valve (20). A later additional infusion of grey water further
elevates the water level and submerges the float to provide the additional
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upward force to the locking arm required to finally lock the valve closed,
now prepared for another rainwater dosing requirement.
Referring now to Figures 1 and 3, there is shown the grey water storage
S tank (46) In greater detail. The grey water tank irt this figure is
illustrated
as rectangular but it can be other shapes. Elements illustrated in Figure 3
include conduit (48) from the rain water tank (38), self regulating valve
(20) mounted in wall (50) of the grey water storage tank, tank lower
baffle plate (200) and tank upper baffle plate (202), tank vent (204), tank
overflow pipe (206) which is connected to the domestic sewer, grey water
collection system intake pipe (44) and domestic hot water connections
ti lb) to the hot water tank (105). Domestic cold water pipes are shown
as item (45). Grey water will enter the grey water tank as shown in Figure
3. The water will flush the sitting water retained by the lower baffle and
have the opportunity to settle. Any grey water components float to the
surface of the water. The top baffle ensures that these components do
not enter the pump side of the grey water storage tank. The lower baffle
retains a body of water and allows the settling of any sinking grey water
components. As the level of intake water rises in the grey water tank, the
floating matter will be forced out of the tank by way of the overflow pipe
which is connected to the domestic sewer. The overflow pipe has a trap
(not shown) to prevent backflow of sewer gas lnto the grey water tank.
The grey water tank can be periodically accessed by a hatchway (not
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shown) and cleaned of the settled matter. The pump (22) is disposed in
close proximity to the grey water tank (46) and is powered by a source of
12VDC power (43) which source powers the programmable controller
(! 12) as well. In the example shown the pump is placed on the top
S surface (70) of the grey water tank but it could be located elsewhere. The
pump comprises a suction conduit (72) having an intake (74) With an
intai<e filter (76) disposed proximate to the bottom (78) of the grey water
tank (46). There is also a discharge conduit (80) in fluid communication
by conduit (82 - See Figure 1) with the at least one toilet fixture storage
tank (26). The pump (22) further comprises a pressure switch (84) for
pump control by sensing fluid pressure in the discharge conduit (80).
When the at least one toilet fixture storage tank (26) is flushed, the toilet
tank valve opens, and a low pressure is sensed by the pressure switch.
The switch turns the pump on to pump water from the grey water storage
tank to the toilet tank. When the toilet tank reaches afutl state its valve
closes, thus the pressure switch senses a high pressure and turns the
pump off.
Now referring to Figures 1, 3 and 4, various elements of means (28) for
keeping the predetermined volume of grey water at a desired
temperature are illustrated. Means (28) comprises a heat exchange
circuit (92). The exchange circuit (92) comprises at least one solar
energy collector (94) in recirculating heat transfer fluid communication by
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conduits (96) and (98) with a radiating heat exchanger (99) disposed
within the grey water storage tank (46) and submerged below the bottom
baffle level (See Figure 3, Item 200) . The radiating heat exchanger (99)
comprises a heat transfer fluid intake (100), a heat transfer fluid
discharge (102) and a radiating coil (104) between said heat transfer
intake (100) and discharge (102). The radiating heat exchanger is
adapted to radiate collected solar energy from the recirculating heat
transfer fluid within the heat exchange circuit into the stored grey water
until said desired temperature Is achi:eved. As shown tn Figure 4, the
radiating heat exchanger (99) comprises a sheet of copper (108) with the
radiating coil (104) on the underside and a domestic water heating coil
{110) on the top side of the copper sheet. The coils are fixed to the
copper sheet by suitable fixing means such as solder (1117). The copper
sheet transfers heat by conduction from the heat transfer coil to the
domestic water heating coil 0 10). The domestic water heating coil (1 10)
has an intake {107) for cold domestic water and a hot water output (1 09)
coupled to conduit (106) into the domestic water heater (105). The
tubing used in the heat exchanger is copper but other materials with
suitable heat transfer properties can be used. The heat transfer fluid is a
mix of propylene glycol/water but any suitable heat transfer fluid can be
used.
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The recirculating heat transfer fluid Is recirculated by a pump (119). The
pump is a two stage pump. The controller can sense a temperature drop
in domestic water supply tubing as it enters the heat exchanger and
Interprets this as a hot water demand. The controller will then switch
from pumping the heat transfer fluid from the low rate to the high rate so
as to heat the water as quickly as possible. The heat exchange circuit is
controlled by programmable control means (112) comprising temperature
sensing means (114) and adapted to maintain the temperature of the
recirculating heat transfer fluid within a first desired range and the
temperature of the grey water within the grey water storage tank within a
second desired range.
Referring now to Figure 5 there is shown another example (500) of the
invention. This example of the invention is intended to be portable and
easy to install in any bathroom. in this example the integrated domestic
water storage system comprises means (502) for collecting a
predetermined volume of grey water, means (504) for storing the
predetermined volume of grey water, a pump (506) for distributing a
demand amount of grey water from the storage means to a toilet fixture
storage tank (508) for flushing and programmable control means (524)
for controlling the flow of domestic water through an air-gap (509) into
the means for collecting and means for storing a predetermined volume
of grey water which comprises a bathtub (51 0). In another example there
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may be an additional storage tank disposed below the bathtub to collect
and store grey water drained from the bathtub. in that example, the
pump suction would be located at the bottom of the storage tank. The
bathtub is supplied with domestic water by normal means (not shown).
S The pump (506) Is disposed in close proximity to the bathtub and
comprises a suction conduit (512) having an intake (514) with an intake
filter (516) disposed on the bottom (518) of the bathtub or adjacent tank
and a discharge conduit (520) in fluid communication with the toilet
storage tank (508). The pump further comprises a pressure switch (522)
for sensing fluid pressure in the discharge conduit so that when the toilet
fixture storage tank is flushed the pump starts and pumps water from the
tub to the empty toilet fixture tank. The system is controlled by way of a
programmable controller (524) connected by plurality of cables (526) to a
plurality of sensors and powered by a source of 12VDC power (528),
which source powers the pump (506) as well. The controller determines if
the water level is dropping to near the elevation of the pump Intake
(514), at which time it opens solenoid valve (526) to allow a dose of
domestic water to enter the storage means via a conduit (51 1) to meet
the demand of the pump.
Accordingly, the reader will see that the integrated domestic utility
system of this invention has the advantages of using simple components,
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ease of installation in a pre-existing home over a prewexisting domestic
water system with few modifications to that system, no reliance upon
toxic chemicals for water purification, use of readily available solar
energy for heating, use of readily available rain water for domestic norr-
potable uses, small scale applications within an individual bathroom and
inexpensive installation to encourage adoption by the public.
Although the description above contains specificities, these should not be
construed as limiting the scope of the invention but as merely providing
illustrations of some of the examples of the invention. For example, the
storage tanks can be any useful shape and volume and the pumps can be
AC or DC powered. Thus the scope of the invention should be
determined by the appended claims and their legal equivalents rather
than by the examples given herein.
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