Note: Descriptions are shown in the official language in which they were submitted.
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2~7~68
TECHNICAL FIELD
The present invention relates to an insulating
jacket which completely surrounds an electric or gas
water heater tank and disposed between the tank inner
and out~r casings, and which is comprised of an
~insul~ting support base, an insulating sleeve, and an
in~ulating cap, with the cap and sleeve being received
within an outer casing of the tank.
BACKGROUND ART
Hot water tanks are constructed of an inner casing
in which water is heated by electrical resistive
elements or a gas or oil burner. An outer casing is
spaced from the inner casing and insulating fiberglass
material is positioned between the side wall of the
tank inner casing and the outer casing. A metal cover
is usually disposed on top of the tank over the outer
casing and usually in contact with the top wall of the
inner casing. The waterline coupling on the top wall
of the tank protrudes through the cover.
A disadvantage of this type of tank construction
is that there is no insulation of the tank in the
bottom wall or top wall thereof where there is
considerable heat loss.
It is also known in the prior art to wrap an
insulatlng blanket about the outer casing to minimize
heat loss therethrough.
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SUMMARY OF INVENTION -
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It is a feature of the present invention to
provide an insulating jacket which completely surrounds
the inner casing of a hot water heating tank and which
substantially overcomes the above-mentioned disadvan- ~
tages of the prior art hot water tank insulation. - `
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According to another feature of the present inven-
tion there is provided an insulating jacket for a hot
water tank inner casing and comprised of an insulating
base, an insulating side wall sleeve, and an insulating
top wal.l cap, with the cap and the base being molded
from foam insulat.ing material.
~ ccording -to the above features, from a broad
aspect, the present invention provides an insulating
jacket ~or a water heater tank inner casing. The
jacket is formed by a circular base of rigid molded
insulating foam material having a flat bottom wall and
a concentrically disposed support dome on a top face
thereof, and shaped for close fit within a bottom
cavity of the tank for support engagement in at least
sections thereof with a bottom wall of the inner casing
of the tank. A spacer ledge is defined about the
support dome and extends to an outer edge of the flat
circular base beyond the inner casing. An insulating
material is disposed about a side wall of the tank and
extends over the spacer ledge. A layer of reflective
sheet material is positioned about the side wall of the
inner casing with the insulating material thereover. A
rigid insulating cap of molded insulating foam material
is positioned over a top wall of the tank inner casing
and extends substantially flush with an outer surface
of the insulating sleeve. An outer metal tank casing
is provided about the side wall insulating material and
the insulating cap and extending to the support base.
According to a further broad aspect, there is
provided in a cylindrical water heating tank having an
insulating material disposed between a side wall of an :
inner casing of said tank and a spaced outer casing,
said tank supported on an insulating base formed of
thermally insulating material, the improvement compris-
ing a rigid insulating cap of molded insulating foam
.
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material positioned in contact over a top wall of said
tank inner casing and extending substantially flush
wi-th an inner surface of said outer casing, said outer
casing extending over said insulating cap.
~RIE~ DESCRIPTION OF DRAWINGS
A pxe~erred embodiment of the present invention
wilL now be described with reference to the accompany-
ing drawings in which:
FIGURE 1 is a fragmented view, partly in section,
of a cylindrical electric water heater tank incorporat-
ing the insulating jacket of the present invention; and
FIGURE 2 is a section view of the bottom section
of a cylindrical electric water heater of the prior
art.
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DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, and more particu-
larly to Figure 1, there is shown generally at 10 a
water heater tank having an inner casing 11 defining a
side wall 11', a top wall 14, and a bottom wall 16
formed as a dome cavity. Electrical resistive heating
elements 15 and 15' are spaced within the hot water
tank casing 10 to heat the water therein. The tank
could be fitted with a gas burner instead of eleatrical
resistive elements to heat the water. A coupling 9 is
provided in the-top wall 14 to connect to a hot water-
line. A cold water inlet coupling 8 is further
provided adjacent the bottom wall 16 of the tank.
As shown in Figure 1, the tank inner casing is `
supported on a circular base 20 of rigid molded
insulating foam material. The base has a flat bottom
wall 21 having a concentrically disposed support dome
22 which is herein formed by radiating dome-shaped ribs
22'. The dome top surface is shaped for close fit
within the bottom cavity 16 for support engagement with
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the bottom wall 16 of the tank. A spacer ledge 23 is
defined about the support base and extends to an outer
edge 2~ thereof beyond the inner casing side wall 11'
and for close fit within the base of an outer casing
1.2.
A la~er of reflective sheet material 26 is
dlsposed about the side wall of the tank. This reflec-
tive material may be formed of metallic foil shee-ting,
or Oe a plastic sheet that has a reflective power
capable of withstanding the heat generated by the hot
water tank and acting as a thermal barrier. An
insulating sleeve 13 of insulating material, such as
fiberglass or equivalent fiber material is rolled in
one or more layers about the reflective material 26 to
eliminate the chimney effect on the side wall of the
inner casing. The fiberglass has a specific density as
required to provide proper insulation of the side wall.
The use of this insulation is known in the prior art,
but the reflective material disposed directly between
the tank inner casing and the insulating fiberglass
sheeting further cuts the heat loss.
A rigid thick insulating cap 27 of molded insulat-
ing foam material, such as polystyrene which is free of
CFE, is positioned over the top wall 14 of the tank
inner casing, and extends outwardly substantially flush
with the outer surface of the side wall insulating -
layer or sleeve 13. The outer casing 12 receives both
the insulating sleeve 13 about the side wall and the
insulating cap 27. Accordingly, the inner casing is
completely enveloped with an insulating material. The
outer casing 12 is also provided with removable panels
28 for access to various accessories connected to the
tank inner casing, such as the couplings 8 and 9,
electrical wiring for the resistive heating elements
15, controls to adjust the temperature of the water,
etc.
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As shown in Figure 1, the tank inner casing 11 is
also suppor-ted entirely on the insulating base. Also,
the insulating cap 27 is provided with cavities or
through bores, such as bore 29, to receive fittings or
okher accessories that may be provided on the outside
surEace of the top wall 1~ of the inner casing. The
support base 20 is also formed with a circumferential
;Locatin~ channel 30 in the top face of the spacer ledge
23 and positioned immediately about the support dome to
receive a lower flange edge 25 of the tank inner casing
and in sealing engagement therewith.
Figure 2 illustrates a prior art design, and as
herein shown, the surface of the bottom wall 16 of the
inner casing is not in support contact with the base,
and accordingly the load of the tank is not distributed -
over the insulated base 19, but peripherally about the
tank. ~his provides for the circumferential edge 30
bearing all the load and damaging the insulating base
19. With this type of construction, there is heat loss
through the bottom wall 16 of the inner casing. -
Although not shown, the top wall of these tanks are
also not insulated. Also, the side wall is provided
with fiberglass insulation 13' which is often loosely
packed and is in direct contact with the inner casing
outer side wall 11'. There is no barrier layer on the
inner casing.
It is within the ambit of the present invention to
cover any obvious modifications of the preferred
embodiment described herein, provided such modifica-
tions fall within the scope of the appended claims.
For example, the outer casing may be formed in two
sections, and namely with an open ended cylindrical
sleeve to fit over and spaced from the side wall 11' of
the inner casing 11, and a top cover section which
secures to the top end of the cylinder to receive the
insulating cap therein. This would facilitate the
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assembly and properly dispose the fiberglass insulation
in the top edge of the tank. Also, the insulating cap
27 may be formed to extend entirely over the dome-
shaped top wall of the tank, and even extend downwardly
i.n a top portion oE the tank side wall. Although the
tank as herein shown has a dome-shaped top wall, it may
also have a flat top wall and the insulating cap 27
would be molded to adapt to the flat top wall and its
couplings. As shown in Figure 1 the tank is provided
with a Eurther heating element 38 secured by the strap-
ping 37 to the side wall of the tank to provide further
heating of the water in the lower por-tion of the tank,
and this prevents the formation of bacteria legionella.
The insulating jacket 13 as well as the reflective
aluminum foil sheeting 26 extends over this auxiliary
heater 38.
