Note: Descriptions are shown in the official language in which they were submitted.
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INSULATING LINER FOR A WATER CLOSET TANK
Back~round of the Invention
A. Field o the Invention
This invention relates to water closets in which the
water storage tank has a restricted top opening. Specifically,
it resides in an insulating liner which is specially designed
for use with such tanks.
B. _escription of the Art
Sweating o water closet tanks on hot and humid days
has long been a source of annoyance, and a cause of damage
to bathroom floors. For this reason, drip trays attached to
the bottom of the flush tank were developed to catch conden-
sation. However, these trays were found to be objectionable
because of the sanitary and odor problems which resulted
when the condensation stood in the tray for extended periods
o time.
Another attempt to solve the condensation problem
involved the application of an absorbent fabric to the
exterior surface of the tank. This covering was intended to
soak up any condensation which formed on the tank, and then
to let moisture evaporate slowly during less humid periods.
. However, this approach was unsatisfactory because the fabric
could easily become saturated, and because damp fabrics can
sufer severe odor problems.
The art then turned to the use o~ insulating liners
which fit inside the toilet tank. These liners formed an
insulating barrier between the cold storage water and the
outside tank wall, and thus the formation o condensation on
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the exterior of the toilet tank walls was inhibited. One
type of prior art liner, a preformed rectangular rigid
plastic liner, could be slid into the top opening of a
rectangular tank. Another type of liner, another form of
rigid plastic liner, could be formed in place by various
casting methods.
While such liners were acceptable for conventional
rectangular tank designs, highly ornamental water closets
were developed that had tanks that were "low profile" and
generally trapezoidal in shape. When conventional
rectangular preformed liners are placed into these low pro-
file, trape~oidal shaped tanks, there is often too much
waste of water storage space along the sides of the tank.
This volume loss is critical due to the additional loss from
narrowing of the tank near its top. (The less storage water
available, the harder it is to completely clean the bowl
with one flush.)
If one chooses to maka a prior art rigid preformed
liner conform to the design of a trapezoidal tank (so as to
maximize water storage space), one would not be able to get
the rigid liner through the "restricted" top opening.
Moreover, if one tries to mold a liner in place ~hich con-
forms to the inwardly sloping tank walls, conventional
molding techniques become very difficult and expensive (e.g.
getting a one-piece core out of a negative mold~.
Thus, it can be seen that the need has existed for an
improved means of preventing water condensation on the
exterior of a low proile, trapezoidal shaped toilet tank.
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Summary of t_e Invention
The present invention provides an insulating liner
for a water closet tan~ that has bottom and side tank walls
and a top tank opening; said tank walls defining a tank water
storage chamber, at least part of which is larger in
hori.zontal cross sectional area than the top opening of the
tank; said liner comprising:
bottom and side liner walls that are formed so as to be
substantially coextensive with the interior surface of the
tan~ bottom wall and tank side walls;
the liner walls normally bei~g--configured so that the
horizontal cross sectional area defined by the exterior of
the liner side walls at a certain height is greater than the
cross sectional area of the tank top opening, and the liner
side walls are suitable to lie against the interior of the
tank side walls; said liner being formed out of a flexible
and resilient material so that the liner can be collapsed
for insertion in the tank through the tank top opening, and
then be released to resiliently return it to its normal
configuration;
said liner having a horizontal cross section which
defines at least one set of opposed liner side walls; and
said liner being sufficiently flexible and resilient
so that the upper ends of the opposed liner side walls may be
folded inwardly towards each other to permit the opposed
side walls to touch each other along lateral sides of the folds,
and then resil.iently return to their normal position without
substantial deformation of the liner.
The preferred liner material is low densit~ foamed
pol.yethylene, a material having great insulating properties,
which is suitable for use in a water environment, and which
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is very flexible and resilient. While the entire liner can
be formed in a rotational molding process, other conventional
molding techniques may also prove to be appropriate. Also,
rather than making the entire liner structure of the flexible
and resilient~material, just the bottom wall of the liner
can be formed of the material, and/or one or more of the
side walls of the liner.
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In an especially preferred e~odiment, the liner is
generally rectangular in horizontal cross section to define
opposed sets o liner side walls, and at least one set of
the opposed liner side walls converges inwardly and upwardly
from the bottom wall. Similarly, both sets of opposed liner
side walls can converge inwardly and upwardly from the
bottom wall.
An especially desirable aspect of the present invention
is that the liner can be formed with a bottom wall that has
a saddle shape in which there is a raised portion having an
outlet hole formed in it, and a lower portion adjacent to
the raised portion in which there is an inlet hole formed.
This design renders the liner especially suitable for use
where building codes require the outlet to be elevated with
respect to certain siphoning elements of the bowl to prevent
backflow, yet water storage capability must be maximized.
The objects of ihe invention therefore include:
a. providing an insulating liner of the above kind
which inhibits water condensation on the outside of a gen-
erally trapezoidal, low profile water tank;
b. providing an insulating liner of the above kindwhich is collapsible so as to allow easy installation through
a restricted tank top opening, yet which is sufficiently
- resilient so as to return to its normal configuration after
insertion in the tank;
c. providing a very thin insulating liner of the
above kind which maximizes water storage space;
d. providing an insulating liner of the above kind
which is inexpensively constructed and installed, and which
is highly durable
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These and still other objects and advantages of the
invention will be apparent from the description which fol-
lows. In this description, the preferred embodiments of the
invention will be described with reference to the accompany-
ing drawings. These embodiments do not represent the fullscope of the invention, but rather the invention may be
employed in other embodiments. Reference is therefore to be
made to the claims herein for interpreting the scope of the
invention.
Brief Description of the ~rawings
Fig. 1 is a perspective view of a low profile water
closet having a generally trapezoidal shaped water storage
tank;
Fig. 2 is a top plan view of the water closet of Fig.
1, with the tank cover removed;
Fig. 3 is a front elevational view of the liner of the
present invention;
Fig. 4 is a top plan view thereof;
Fig. 5 is a cross sectional view taken across the
middle of the liner of Fig. 3;
Fig. 6 is a perspective showing the liner of Fig. 3 in
a partially collapsed condition during installation of the
liner in a toilet tank;
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Fig. 7 is a partial sectional view taken on line 7-7 of
Fig. 2, after the liner of the present invention and por-
tions of the flush control m~chanism have been installed in
the tank; and
Fig. 8 is a partial sectional view taken on line 8-8 of
Fig. 2 after the liner of the present invention and portions
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of the flush control mechanism have been installed in the
tank.
Description of the Preferred Embodiments
In Figs. 1 and 2 of the drawings, there is shown a low
profile water closet 10 having a generally trapezoidal
shaped water storage tank 11. The toilet has the usual bowl
12, trip lever 13, and toilet tank lid 14.
The tank 11 has a front side wall 15, a rear side wall
16, a left side wall 17, a right side wall 18, and as best
seen in Fig. 7, a bottom tank wall 19. At the top of the
tank 11 there is a restricted top opening 20. "Restricted"
is used in this context to mean that the area of the opening
is less than the horizontal cross sectional area of the
tank wata~ chamber at a certain height, the water chamber
being defined by the interior surfaces of walls 15-19.
Other features of the tank 11 include an inlet 22
through which water is received, and an outlet 23 through
which water exits. In the usual way, a conventional inlet
float valve 25 (see Fig. 8) can control the inflow of water
in response to the water level of the tank, and conventional
outlet flush hall 26 can be activated by the toilet trip
lever 13.
The liner 28 is depicted in detail in Figs. 3-5 of the
drawings. It has a front side wall 2g, right and left side
walls 30 and 31, a rear side wall 32, and a bottom wall 33.
Opposed side walls 30 and 31 slope upwardly and inwardly
towards each okher as do opposed side walls 28 and 29. This
forms the generally trapezoidal outer shape of the liner 28.
It will also be appreciated that a horizontal cross
section through the liner side walls will be generally
rectangular. As can be seen from Fig. 4, the term "gen-
erally" rectangular is meant to include walls such as wall
29 even though they have an irregularity such as a contour.
The liner 28 also has an inlet hole 36 which corres-
ponds to the tank inlet hole 22, and a bottom wall outlet 37which corresponds to the tank outlet 23. The bottom liner
wall 33 has a raised central portion 39 in which the outlet
hole 37 is formed, and two lower portions 38 adjacent to the
raised portion 39. The inlet hole 3~ is formed in one of
the lower portions 38. When viewed as in Fig. 3, the bottom
wall of the liner therefore takes on a "saddle" shape.
The position of the trip lever 13 on the outside of the
tank 11 can, of course, be varied. For certain placements,
a cut such as cut 40 can be made in the liner 28 so as to
allow for appropriate clearance of the trip lever mechanism
once the trip lever 13 is positioned.
It will be appreciated from Figs. 7 and 8 that the
liner side and bottom walls 28-33 are formed so as to be
substantially coextensive with the interior surface of the
tank bottom and tank side walls 15-19, and the liner side
walls are designed to lie against the tank side walls 15-18.
The term "substantially" is used in this context so as to
include situations where the liner walls do not conform
exactly to the tank walls. Note for example that Figs. 7
and 8 show that to save material some space can be left
below the back portion of bottom wall 39 and/or along the
lower side corners of the liner 28. Also, Fig. 7 shows that
the liner need not extend all the way to the top of the tank
11. Normally, however, the liner 28 will be molded so as to
conform as closely as possible to the tank interior to save
water storage space.
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The liner 28 can be formed of foamed polyethylene 42
which has a density of less than .35 ~rams per cubic centi-
meter. Other materials (e.g. plastics) might also prove
suitable although the material should have many desirable
characteristics. For example, it should be sufficiently
flexible so that the liner can be collapsed for insertion in
the tank as shown in Fig. 6, and then be sufficiently
resilient to return to its normal configuration without
substantial deformation. At the same time, the material
should be sufficiently thick to inhibit condensation, yet
not so thick as to take up needed water storage space.
Excellent insulating properties are therefore required.
Also, the material should be extremely durable in various
types of water environments. Because a material must have
all these characteristics, selection of a material requires O
great care.
To form the preferred polyethylene liner 28, a number
of conventional molding techniques can be used. For example,
medium density polyethylene can be placed in a rotational
mold. A standard USI foaming agent can then be placed in
the mold, and the walls of the mold can then be heated as
the mold is slowly rotated. During this process, the heated
medium density polyethylene will turn into low density
polyethylene foam that adheres to the walls of the core.
While the liner 28 is shown as being formed entirely from
low density ~oamed polyethylene, the liner will also be
suitable or some applications if just the side and/or
bottom wall(s) of the liner are ~lexible an~ resilient.
Fig. 6 shows how the liner 28 is installed. ~t is
simply crushed liXe a piece of paper, inserted through
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the opening 20, and then released. As an added feature, the
liner can be held in place by appropriate adhesives 44.
Thus, the invention provides an improved means of
inhibiting water condensation on the exterior of a toilet
tank that has a restricted top opening. While the preferred
embodiments have been described above, it should be apparent
to those skilled in the art that a number of modifications
and changes can be made to the preferred embodiments without
departing from the spirit and scope of the invention.
For example, while the water closet tank and liner
shown in the drawings are both of a generally trapezoidal
shape, other water closet tank and liner shapes can
incorporate the present invention. For example, instead of
a straight sloping trapezoidal shape, the tank and liner
side wall could have a series of inwardly directed steps.
