Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02644908 2008-11-26
Attorney Docket: 2415-2/MBE
SYSTEM AND METHOD FOR RESTORING
WATER SUPPLY PIPES IN BUILDINGS
FIELD OF THE INVENTION
[00011 The present invention relates to piping systems. In particular, the
present
invention relates to restoring water supply pipes in buildings.
BACKGROUND OF THE INVENTION
[00021 Fluid conduits such as gas pipes, sewer pipes and water pipes are
susceptible to
the build-up of rust and scale on the inner surface of the pipe. This may be
caused by
corrosion of the inner pipe surface and/or the deposit of accretions onto the
pipe surface,
such as lime or other deposits of solids, from fluids moving in the pipe. Over
time, rust
and scale accumulate inside the pipe, which reduces the volume of flow through
the pipe.
Corrosion and erosion also deteriorate pipe walls, ultimately causing pits,
pinhole leaks
and major leaks necessitating replacement of the pipe.
[00031 Restoration of existing pipes by pipe lining can extend the useful life
of pipes and
thus reduce the frequency by which pipes need to be replaced. Pipe lining also
takes less
time to complete and costs less than replacing pipes. It also does not require
holes to be
made in walls.
100041 A known method of pipe restoration by pipe lining is to first clean the
pipes by
draining the pipes, blowing heated compressed air, first by itself to dry the
pipes, and then
carrying particles of abrasive material through the pipes to dislodge the
build-up on the
inner surface of the pipe. An epoxy coating is then applied to the interior
walls of the
pipes by using the heated compressed air to blow epoxy through the pipes. The
smooth
coat of epoxy fills in pits and pinhole leaks and protects the pipes from
corrosion and
erosion. If only pipe cleaning is desired, the step of blowing the epoxy
through the pipes
is omitted.
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[0005] Where such a method of pipe cleaning or restoration is carried out on
the water
supply pipes in a building, such as an apartment building, compressed air
supply hoses
are used to deliver the compressed air to each apartment unit. The hoses are
then
connected to a pipe in the apartment, such as a hot or cold water pipe in the
kitchen, and
the compressed air is blown through that branch pipe into the hot or cold
water riser to an
end of the riser, usually in the basement of the building, where the pipe has
been cut open
to vent the compressed air carrying the abrasive material and dislodged build-
up through
a hose and into filter and then into the open air. To deliver the compressed
air to each
apartment unit, the compressed air supply hoses are typically run from an air
compressor
on the ground outside of the building to an apartment unit through a window or
balcony
door in every apartment unit. Alternatively, compressed air supply hoses are
run through
the staircases of the building and then through the front door of each
apartment unit.
Either of these alternatives is dangerous as it requires a door or window to
the apartment
to remain open and unlocked, leaving the tenant or occupant vulnerable to
theft or other
crime. Furthermore, running air supply hoses to each individual apartment unit
is labour-
intensive and expensive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In drawings which illustrate by way of example only a preferred
embodiment of
the invention,
[0007] Figure 1 is a schematic diagram showing a prior art system for cleaning
and/or
lining a hot water riser in a typical hot and cold water piping system found
in a residential
apartment building;
[0008] Figure 2 is a schematic diagram showing a system for cleaning and/or
lining hot
and cold water supply pipes according to the present invention, as applied to
the hot and
cold water pipes shown Figure 1; and
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[0009] Figure 3 is a schematic diagram showing an alternative connection
between a hot
water pipe branch and a cold water pipe branch in a residential apartment unit
on hot and
cold water risers.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention relates to a system and method for restoring
water supply
pipes in buildings. The present invention can be beneficially employed in
various types of
buildings, such as high-rise condominium buildings, offices, apartments,
hospitals and
hotels.
[0011] The present invention eliminates the need for running compressed air
supply
hoses to the pipes in each apartment unit in order to supply the compressed
air to clean or
restore the hot and cold water pipes.
[0012] The present invention relates to a system for cleaning at least a
section of a water
supply pipe in a building having isolated and dried first and second supply
pipes for
supplying cold and hot water, comprising: a supply of compressed gas for
supplying a
stream of compressed gas into an inlet of a first supply pipe at an upstream
position along
the pipe; a second supply pipe comprising an outlet for venting the compressed
gas; a
supply of abrasive particles for cleaning an interior of the at least one
section of either the
second supply pipe or the first supply pipe or both, where the abrasive
particles are
introduced into the stream of compressed gas upstream of the at least one
section of pipe
to be cleaned; and an air-impermeable conduit connecting the interior of the
first supply
pipe to the interior of the second supply pipe such that pressurizing the
first supply pipe
pressurizes the second supply pipe.
[0013] The present invention also relates to a system for lining at least a
section of a
water supply pipe with an epoxy coating in a building having isolated and
dried first and
second supply pipes for supplying cold and hot water, comprising: a supply of
compressed gas for supplying a stream of compressed gas into an inlet of a
first supply
pipe at an upstream position along the pipe; a second supply pipe comprising
an outlet for
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venting the compressed gas; a supply of epoxy coating for lining the interior
of the at
least one section of either the second supply pipe or the first supply pipe or
both, where
the epoxy coating is introduced into the stream of compressed gas upstream of
the at least
one section of pipe to be lined; and an air-impermeable conduit connecting the
interior of
the first supply pipe to the interior of the second supply pipe such that
pressurizing the
first supply pipe pressurizes the second supply pipe.
100141 The present invention also relates to a method of cleaning at least a
section of a
water supply pipe in a building having isolated and dried first and second
supply pipes for
supplying cold and hot water, comprising: pneumatically connecting a first
supply pipe to
a second supply pipe such that pressurizing the first supply pipe pressurizes
the second
supply pipe; blowing a stream of compressed gas into an inlet of the first
supply pipe, at
an upstream position along the pipe; introducing abrasive particles into the
stream of
compressed gas upstream of the at least one section of pipe to be cleaned; and
venting the
compressed gas and any dislodged build-up from an outlet of the second supply
pipe.
tools) The present invention also relates to a method of lining at least a
section of a
water supply pipe in a building having isolated and dried first and second
supply pipes for
supplying cold and hot water, comprising: pneumatically connecting a first
supply pipe to
a second supply pipe such that pressurizing the first supply pipe pressurizes
the second
supply pipe; blowing a stream of compressed gas into an inlet of the first
supply pipe, at
an upstream position along the pipe; introducing an epoxy coating into the
stream of
compressed gas upstream of the at least one section of pipe to be lined; and
venting the
compressed gas and any excess epoxy coating from an outlet of the second
supply pipe.
[0016) Figure 1 shows a prior art system for cleaning and/or lining a hot
water riser in a
typical hot and cold water piping system found in a residential apartment
building. Hot
water riser 10 and cold water riser 20 supply water to occupants on each floor
of the
building. An air compressor 30 is outside the building and optionally
connected to a
heater 35 for heating the compressed air. Air supply hoses 40 are run from the
heater 35
to each apartment serviced by the hot water riser 10 and cold water riser 20.
The air
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supply hoses 40 enter the apartment unit through a window or balcony door and,
to clean
the hot water riser 10, are connected to the hot water branch 15 feeding into
the hot water
riser 10 being cleaning or lined. Alternatively, the air supply hoses 40 are
run inside the
building through a staircase and hallways to and through the front doors of
each
apartment unit served by the hot water riser 10 and cold water riser 20.
[00171 In the prior art system shown in Figure 1, a cleaning device for
example a device
for supplying aluminum oxide, such as aluminum oxide blaster 50, is brought
into the
apartment unit and is used to supply the aluminum oxide into the compressed
air stream
prior to it entering into the hot water branch 15 feeding into the hot water
riser 10.
Similarly, where lining of the pipes is also desired, a coating device such as
a device for
supplying an epoxy coating 60 for pipe lining is also brought into the
apartment unit and
is used to supply the epoxy into the compressed air stream prior to it
entering the hot
water branch 15. The compressed air stream is vented through an outlet 70 in
the hot
water riser, usually in the basement of the building, through a hose into an
air filter 80 to
filter out the aluminum oxide, dislodged debris or excess epoxy.
[00181 Figure 2 shows a system for cleaning and/or lining hot and cold water
supply
pipes according to the present invention, as applied to the hot and cold water
pipes shown
in figure 1. In Figure 2, the air compressor 30 is in the basement of the
building and is
connected to the optional heater 35 and then to an inlet 90 where the pipe on
the cold
water riser 20 has been cut on the riser side of isolation valve 100. The cold
water riser 20
is used as a conduit to supply compressed air to the hot water riser 10 by
connecting the
cold water riser 20 to the hot water riser 10 by a pneumatic conduit, such as
riser air hose
110. By using the cold water riser 20 to supply compressed air to hot water
riser 10, the
present invention eliminates the need for multiple compressed air supply hoses
40.
Instead the present invention uses only one compressed air supply hose 40.
This
arrangement of the present invention may considerably reduce labour costs
incurred in a
pipe cleaning or restoring job, and avoids having to feed air supply hoses
into individual
units in the building.
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100191 Before cleaning and/or lining can be commenced the water flow to the
pipes is
shut-off at isolation valves 100, and then the pipes are drained and dried.
After the
draining process is completed, the drying process can be accelerated by
supplying a
stream of compressed air through the hot and cold water supply pipes,
especially when
the compressed air is heated by the optional heater 35. Heating the compressed
air also
accelerates the drying of the epoxy coating when the pipes are being lined.
Preferably, the
compressed air is heated to a temperature between 20 degrees Celsius and 60
degrees
Celsius.
[0020] The preferred abrasive material used to clean the pipes is aluminum
oxide or
corundum, however any suitable abrasive that has been approved for use in pipe
cleaning
by the applicable regulators, if necessary, may be used. It may also possible
to reuse the
abrasive captured by air filter 80 a few times if desired.
[00211 The preferred epoxy coating is a two-component epoxy (hardener and
resin) that
has been approved for pipe lining by the applicable regulatory authorities if
necessary,
such as National Sanitation Foundation (NSF) 61 for pipes of a half-inch or
larger in
diameter.
100221 The supply of compressed gas is preferably a supply of compressed air,
such as an
air compressor, although other gases could be used instead of air, including
inert gases
such as carbon dioxide.
[00231 Either hot water supply pipes, such as a hot water riser, or cold water
supply
pipes, such as a cold water riser, or both, can be cleaned and/or lined
according to the
present invention. A hot water riser is typically made of copper piping, but
may
alternatively be made of galvanized steel or iron piping. A hot water riser 10
made of
copper piping will erode more quickly than a cold water riser 20 made of
copper piping,
and therefore the hot water riser 10 is typically more likely to require
cleaning and pipe
lining. However, the present invention may also be beneficially employed to
clean and
line cold water pipes. The present invention may be beneficially employed with
kitchen
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and washroom risers as well as other types of risers, such as for heating and
cooling
systems, and other fluid supply lines.
[0024] As shown in Figure 2, an air-impermeable connection is provided between
hot
water riser 10 and a cold water riser 20 which allows the cold water riser 20
to be used for
supplying compressed air into the hot water riser 10. Preferably, this
connection is made
at the top, or opposite end of the riser to the supply of compressed air, of
the hot water
riser 10 and cold water riser 20. The connection is formed by cutting the
pipes of the hot
water riser 10 and the cold water riser 20 and attaching a pneumatic conduit
between the
cut-off pipes, such as riser air hose 110 which is of sufficient strength to
withstand the
force of the stream of compressed air flowing through the cold water riser 20
into the
riser air hose 110 and into the hot water riser 10. At this connection is the
preferred point
for a supply of abrasive particles in the cleaning process, such as aluminum
oxide blaster
50, to introduce the abrasive particles into the stream of compressed air, as
shown in
Figure 2. Similarly, this is the preferred point for a supply of epoxy coating
in the lining
process to introduce the epoxy coating into the stream of compressed air, such
as by
device for supplying an epoxy coating 60, as shown in Figure 2. This location
is preferred
as it allows the entire hot water riser 10 be cleaned or lined from top to
bottom. Abrasive
particles or epoxy coating could be introduced at other points in the piping
system, such
as may be accomplished by connecting the supply of abrasive particles or the
supply of
epoxy coating to a hot water branch 15 or a cold water branch 25, either
existing or
created for cleaning or lining purposes, as long as the branch 15 or 25
connects to the hot
water riser 10 or cold water riser 20 upstream of the section of pipe to be
cleaned or lined.
[0025) After the hot water riser 10 and/or cold water riser 20 has been
cleaned or lined,
there may be some abrasive material or excess epoxy residing in one or more
hot water
branches 15 and/or cold water branches 25. As shown in Figure 2, if necessary
the hot
water branch 15 and a cold water branch 25 may be connected at the shut-off
valves 130
by a pneumatic conduit, such as branch air hose 120, to flow the stream of
compressed air
through the hot water branch 15 and cold water branch 25 and blow out any
abrasive
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material or excess epoxy from the branches 15 and 25 into the risers 10 and 20
and down
to and out the outlet 70. Since the hot water branches 15 and cold water
branches 25 are
not as heavily used as the hot and cold water risers 10 and 20, they will
typically not
experience residue build-up, or erode or corrode, as quickly, and do not need
to be
cleaned or lined as frequently as hot and cold water risers 10 and 20.
[0026] When the interior cross-section of the shut-off valves 130 is too
small, connecting
a branch air hose 120 between the shut-off valves 130 of the hot water branch
15 and cold
water branch 25 will not provide a sufficient flow of compressed gas to blow
out all of
the abrasive material or excess epoxy in the hot water branch 15 and/or cold
water branch
25. In this case, the shut-off valves 130 can be removed and the hot water
pipe branch 15
and the cold water pipe branch 25 are preferably connected by an external
network of
valves shown in Figure 3. A bypass valve 140 is used to allow the stream of
compressed
gas from the cold water branch 25 to flow through to the hot water branch 15.
A ball
valve 150, pressure regulator 160, flow control valve 170 may be used to
control the flow
and pressure of compressed gas into the hot water branch 15.
100271 In some instances, where the pipe diameter of the riser increases in
different
sections of the riser, in order to maintain the pressure it is necessary to
supplement the
supply of compressed air in those increased-diameter sections of the riser by
introducing
further supplies of compressed air. In those cases, further supplies of
compressed air may
be introduced on certain floors of the building, as appropriate given the
placement of the
diameter changes in the riser.
10028] 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.
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