INSULATED HOT WATER HEATER AND METHOD OF INSULATING SAME

CHAUFFE-EAU ISOTHERMIQUE ET METHODE D'ISOLATION

English Abstract

An insulated hot water heater is comprised of an
inner casing defining a reservoir in which water is heated.
An outer casing is disposed about the inner casing and
spaced therefrom to define an insulating space. Heat
insulating material is disposed in the insulating space and
extends at least about a circumferential side wall and a top
wall of the inner tank. A disc of rigid insulating foam
material is disposed between a top wall of the inner casing
and a top wall of the outer casing. A method of thermally
insulating the hot water heater consists of inverting the
water heater and foaming the insulating space with a
thermally insulating foam material whereby to achieve
optimum foam density in the top portion of the hot water
heater between the top wall of the inner casing and the top
wall of the outer casing.

Claims

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CLAIMS,
1. An insulated hot water heater comprising an
inner casing defining a reservoir in which water is heated,
an outer casing disposed about said inner casing and spaced
thereabout to define an insulating space, heat insulating
material in said insulating space and extending at least
about a circumferential side wall and a top wall of said
inner tank, and a disc of rigid insulating foam material
disposed between a top wall of said inner casing and a top
wall of said outer casing.
2. An insulated hot water heater as claimed in
claim 1 wherein said inner casing and outer casing are
cylindrical casings of circular cross-section, said disc
being a circular disc of circular cross-section and of
predetermined thickness
3. An insulated hot water heater as claimed in
claim 2 wherein said disc has an outer diameter selected for
close fit within said outer casing.
4. An insulated hot water heater as claimed in
claim 2 wherein said disc has a flat top wall for flush fit
with said top wall of said outer casing, and a bottom
concavely shaped cavity for close fit with said top wall of
said inner casing.
5. An insulated hot water heater as claimed in
claim 4 wherein said inner tank has a top head portion which
extends from a top end of a cylindrical side wall thereof
and defines a convex top dome portion, said bottom concavely
shaped cavity receiving said top head portion of said inner
casing in flush contact therein.
6. An insulated hot water heater as claimed in
claim 2 wherein said disc is provided with transverse holes

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of cylindrical cross-section to receive, in press fit
therein, conduits for connection to said top wall of said
inner tank.
7. An insulated hot water heater as claimed in
claim 4 wherein there is further provided a thermally
insulated material in said insulating space, said inner
casing being supported on a rigid thermally insulated base.
8. A method of thermally insulating a hot water
heater having an inner casing defining a reservoir in which
water is heated, and an outer casing disposed about said
inner casing and spaced thereabout to define an insulating
space about at least a circumferential side wall and top
wall of said inner casing, said method comprising the steps
of
i) inverting said hot water heater with said top wall
of said inner casing facing downward and spaced
from a top wall of said outer casing, and
ii) foaming said insulating space with a thermally
insulating foam material upwards from said
inverted bottom end of said hot water heater
whereby said foam, when solidified, will have
optimum density in said insulating space between
said top wall of said inner casing and said top
wall of said outer casing.
9. A method as claimed in claim 8 wherein said step
(ii) comprises pouring a thermally insulating liquid foaming
agent in said insulating space from an inverted bottom end
of said hot water heater whereby said liquid foaming agent
with mix with a further reacting framing agent located at a
bottom end of said insulating space in the area of said top
wall of said inner casing and react to form a foam which
will rise in said insulating space from said bottom end.

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10. A method as claimed in claim 9 wherein said step
(ii) comprises placing a first foaming agent of a two part
urethane foam in a lower part of said insulating space where
said inner casing top wall is located, and pouring a second
liquid foaming agent in said insulating space to react with
said first foaming agent to cause an insulating urethane
foam to rise and solidify.
11. A method as claimed in claim 10 wherein there is
further provided the step of placing a plastic film apron in
said insulating space and about said inner casing, said step
(ii) comprising pouring said liquid foaming agent in said
plastic apron, said plastic apron foaming a protective
sheeting against an inner surface of said outer casing after
said insulating urethane foam as solidified.
12. A method as claimed in claim 9 wherein prior to
step (i) there is provided the step of placing a disc of
rigid insulating foam material in close fit between said top
wall of said inner casing and an inner surface of a top wall
of said outer casing.
13. A method as claimed in claim 9 wherein prior to
step (i) there is provided the step of securing a rigid foam
thermally insulating support base over said inverted bottom
end of hot water heater with said support base extending to
said outer casing, said step (ii) comprises pouring said
liquid foaming agent in a pouring hole of said support base
aligned with said insulating space.

Description

CA 02444136 2003-10-08
INSULATED HOT WATER HEATER AND METHOD OF INSULATING SAME
TECHNICAL FIELD
toooi) The present invention relates to an insulated
hot water heater and a method of insulating same whereby to
obtain improved insulating properties in the top portion of
the hot water heater between the inner casing and outer
casing.
BACKGROUND ART
fooo2) Today's hot water heaters are insulated by rigid
foam material which is disposed in the space between the
inner casing and outer casing of the hot water heater. This
is done by pouring in the bottom segment of this space
between the inner casing and the outer casing, a two part
urethane foam which then foams up upwards and fills the
space between the inner casing and the lower casing. This
two part urethane foam can be contained totally or partially
in a plastic apron whereby not to stick to the outer casing
inner walls to provide for ease of recycling. On the other
hand, some of these hot water heaters are foamed without the
use of these protective plastic bags. Once the foam is
solidified the density of the solidified foam is optimum at
the bottom of this space surrounding the inner casing and
nominal at the top, the very portion of the water heater
which is subjected to the hottest water contained within the
inner casing. Accordingly, there is heat loss between the
top portion of the inner casing and the top portion of the
outer casing. Further, connecting pipes admit water to the
inner casing and extracts hot water therefrom through the
top wall of the inner casing. The piping and its bushing
are connected to the top wall of the outer casing and
accordingly conduct heat into this top wall.
tooo3l With the advent of water heaters having to meet
better energy efficiencies imposed by governing agencies,
all aspects of insulation must be studied and improved to

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meet the standards. Our study has shown that a hot water
heater is subjected to approximately 250 of heat losses
through the insulation and the top portion of the water
heater.
SUMMARY OF INVENTION
fooo4l It is a feature of the present invention to
provide an insulated hot water heater and a method of
insulating same which substantially overcomes the above-
mentioned disadvantages of the prior art.
tooo5) According to a broad aspect of the present
invention there is provided an insulated hot water heater
which comprises an inner casing defining a reservoir in
which water is heated. An outer casing is disposed about
the inner casing and spaced thereabout to define an
insulating space. Each insulating material is disposed in
the insulating space and extends at least about a
circumferential side wall and a top wall of the inner tank.
A disc of rigid insulating foam material is disposed between
a top wall of the inner casing and a top wall of the outer
casing.
tooo6l According to a still further broad aspect of the
present invention there is provided a method of thermally
insulating a hot water heater having an inner casing
defining a reservoir in which water is heated. An outer
casing is disposed about the inner casing and spaced
thereabout to define an insulating space about at least a
circumferential side wall and a top wall of the inner
casing. The method comprises the steps of inverting the hot
water heater with the top wall of the inner casing facing
downward and space from a top wall of the outer casing. The
insulating spaces then foamed with a thermally insulating
foam material which foams upward from the inverted bottom
end of the hot water heater whereby the foam, when
solidified, will have optimum density in the insulating

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space between the top wall of the inner casing and the top
wall of the outer casing.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present invention
will now be described with reference to the accompanying
drawings in which:
tooos~ FIG. 1 is a longitudinal cross-section view of a
hot water heater insulated in accordance with the present
invention;
tooo9~ FIG. 2 is a fragmented longitudinal cross-
section view of the top end of the water heater illustrating
a further configuration of the rigid insulating foam disc;
toool.01 FIG. 3 is a view similar to Figure 2 but showing
a further configuration of the rigid insulating foam disc;
too01i1 FIG. 4 is a longitudinal section view
illustrating the method of thermally insulating a hot water
heater with a foaming material;
toooi2) FIG. 5 is a longitudinal cross-section view of
the inverted top end of the hot water heater illustrating a
conventional foaming method, and
toool3) FIG. 6 is a longitudinal section view similar to
Figure 4 but showing the rigid insulating foam disc of
Figure 3 positioned over the inverted top wall of the inner
casing.
DESCRTPTION OF PREFERRED EMBODIMENTS
toool4J Referring now to the drawings and more
particularly to Figure 1 thereshown generally at 10 an
insulated. hot water heater constructed in accordance with
the present invention. It is pointed out that Figure 1 is a
simplified illustration and does not show all of the
component parts and piping of a hot water heater but only
sufficient parts to illustrate the present invention.
toool5l As shown in Figure 1 the water heater comprises
an inner casing 11 which defines a reservoir 12 in which

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water is heated by heating means not shown herein but such
as resistive elements or a combustion chamber which would
necessitate a central flue pipe extending through the inner
casing. This is well known in the art. An outer casing 13
is disposed about the inner casing 11 and spaced therefrom
to define an insulating space 14. Thermally insulating
material at 15 is disposed in the insulating space 14 and
extends at least about the circumferential side wall 11' and
about the top wall 11" of the inner tank 11. A disc of
rigid insulating foam material 16 is disposed between the
top wall 13' of the outer casing 13 and the top wall 11" of
the inner casing 11.
fooois~ The thermally insulating foam material 15 is a
two part urethane foam and wherein a first foaming agent is
disposed in the space 14 in the bottom area 14' of the
insulating space 14 and by pouring a second foaming agent in
the space the material will foam and rise toward the top
area 14" of the space and fill the interstices about the
insulating disc. Accordingly, there is provided improved
insulation in the top area 14" of the insulating space where
the urethane foam is of less density than in the bottom area
14'. By providing the rigid insulating foam material disc
16 the insulation in that area is greatly improved. As
hereinshown the disc 16 is provided with transverse holes 17
and 17' to receive a nipple 18 and 18' for connection
respectively to a cold water inlet piping and a hot water
outlet piping, not shown.
foool~~ As shown in Figure 1 the hot water heater is
provided with a rigid foam insulated support base 19 which
is fully described in a patent assigned to the assignee of
the present invention. It also provides excellent
insulating properties at the bottom end of the hot water
heater 10.
fooois~ As is well known in the art these hot water
heaters are cylindrical heaters and accordingly the inner
and outer casings are also cylindrical shaped. The disc 16

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is a circular disc and provided with a thickness for close
fit between the top wall 11" of the inner casing 11 and the
top wall 13' of the outer casing. The disc at 16 has a flat
top wall 16' for a flush fit with the inner surface of the
top wall 13' of the outer casing. As shown in Figure 2 the
disc also has a bottom concavely shaped cavity 19 for a
close fit with the outer portion of the top wall 11" of the
inner casing 11.
Ioool9l As shown in Figure 3 the cavity 19' of the disc
16' extends entirely about the convex top dome portion 20 of
the inner casing. This diminishes the interstitial spaces
and makes it easier for the foam material to rise in a
substantially non interrupted cylindrical cavity 21 in the
top area 14" of the insulating space 14. The cavity 19' is
in flush contact with the outer surface of the dome portion
20.
fooo2ol Referring now to Figure 4 there is shown a
method of thermally insulating a hot water heater 10' to
obtain optimum foam density in the top area 14" of the
insulating space 14. This method comprises inverting the
hot water heater with the top wall 11" of the inner casing
11 facing downward and space from the top wall 13' of the
outer casing 13 as herein shown the hot water l0' is
supported on a support base 30 provided with cavities 31 and
31' to receive the nipples 18 18' projecting from the top
wall 13' of the outer casing. With the hot water heater
inverted as hereinshown, thermally insulating foam material
is disposed in the insulating space and more specifically in
the top wall area 14" which is now at the bottom of the
inverted hot water heater. The foam material foams upwards
from this inverted bottom end and when solidified the foam
material has optimum density in the top area 14" of the
insulating space 14. As hereinshown the hot water heater is
fitted with the rigid foam insulating support base 19 and
this support base is provided with a pouring hole 32 to
permit the thermally insulating liquid foaming agent to be

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inserted within the space. The pouring hole also provides
an escape hole for the foaming material should there be
excess foam within the insulating space and it also provides
an indication that the foaming material has risen to the top
end of this insulating space.
too02i) As shown in Figure 5 the first foaming agent 33
of a two part urethane part is placed in a plastic film
apron 34 which extends along the insulating space 14 and
preferably against the inner surface of the circumferential
side wall 35 of the outer casing 13 whereby to form a
barrier between the inner side wall of the circumferential
side wall and the urethane foam. This provides for ease of
recycling of the hot water heater whereby the foaming
material does not adhere to the outer casing and it becomes
easy to separate the outer casing from the inner casing as
the outer casing can be reused or recycled. With the first
foaming agent contained within the plastic film apron a
second liquid foaming agent is poured within the space from
the pouring hole 32 and when it reaches the first foaming
agent 33 it reacts therewith causing the foam material to
form and rise and form a rigid urethane insulating foam in
this space 14.
tooo22) As shown in Figure 6 the method may also
comprise placing the disc 16 of rigid insulating foam
material and close fit between the top wall 11" of the inner
casing 11 and the top wall 13' of the outer casing. This
disc 16 also provides excellent support for the inverted
water heater and particularly for the inner casing which is
the heaviest part of the hot water heater being constructed
of steel material. The method of foaming the insulating
space 14 is then repeated as above described.
fooo23) It is within the ambit of the present invention
to cover any obvious modifications of the preferred
embodiments described herein, provided such modifications
fall within the scope of the appended claims.

Representative Drawing