U.S. patent application number 13/428328 was filed with the patent office on 2013-09-26 for holding tank with internally reinforced sidewalls and liquid dispenser using same.
This patent application is currently assigned to PRINCE CASTLE, LLC. The applicant listed for this patent is CHRISTOPHER LYONS, LOREN VELTROP. Invention is credited to CHRISTOPHER LYONS, LOREN VELTROP.
Application Number | 20130248538 13/428328 |
Document ID | / |
Family ID | 49210820 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130248538 |
Kind Code |
A1 |
VELTROP; LOREN ; et
al. |
September 26, 2013 |
Holding Tank With Internally Reinforced Sidewalls and Liquid
Dispenser Using Same
Abstract
The inward and outward deflection of sidewalls of a holding tank
for liquids is reduced or eliminated by sidewall reinforcing
stringers that extend between the sides and which are located
inside the tank. The stringers, maintain the separation distance
between the sidewalls to keep the sidewalls substantially parallel
to each other.
Inventors: |
VELTROP; LOREN; (CHICAGO,
IL) ; LYONS; CHRISTOPHER; (LA GRANGE PARK,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VELTROP; LOREN
LYONS; CHRISTOPHER |
CHICAGO
LA GRANGE PARK |
IL
IL |
US
US |
|
|
Assignee: |
PRINCE CASTLE, LLC
CAROL STREAM
IL
|
Family ID: |
49210820 |
Appl. No.: |
13/428328 |
Filed: |
March 23, 2012 |
Current U.S.
Class: |
220/592.02 ;
220/639 |
Current CPC
Class: |
B67D 7/78 20130101; F16K
7/068 20130101; B65D 1/46 20130101; B65D 25/24 20130101; F25D
23/126 20130101; F25D 23/00 20130101; F25D 2323/122 20130101 |
Class at
Publication: |
220/592.02 ;
220/639 |
International
Class: |
B65D 1/42 20060101
B65D001/42; F25D 23/00 20060101 F25D023/00 |
Claims
1. A liquid holding tank comprising: a first wall; a second wall
opposite the first wall, the first wall and the second wall being
thin; and a first stringer inside the liquid holding tank and
extending between the first and second walls, the stringer
configured to reduce deflection of the first and second holding
tank walls.
2. The liquid holding tank of claim 1, wherein the first and second
walls are substantially planar, substantially vertical,
substantially parallel to each other and wherein the stringer is
formed integrally with both the first wall and second wall.
3. The liquid holding tank of claim 1, wherein the stringer is
attached to the first and second walls by at least one of: welding,
an adhesive and a mechanical fastener.
4. The liquid holding tank of claim 2, wherein the first stringer
and sidewall are formed together and are seamless.
5. The liquid holding tank of claim 3, wherein the first wall and
the second wall have smooth outside surfaces.
6. The liquid holding tank of claim 4, wherein the first stringer
is hollow.
7. The liquid holding tank of claim 5, further comprising a second
stringer, the second stringer being similar to, and vertically
separated from the first stringer.
8. The liquid holding tank of claim 5, further comprising a second
stringer, the second stringer being similar to, and horizontally
separated from the first stringer.
9. The liquid holding tank of claim 6, wherein the first and second
walls have a geometric center and wherein the first and second
stringers extend between the first and second walls at first and
second stringer locations, the first and second stringer locations
being equally spaced away from the geometric center.
10. The liquid holding tank of claim 7, wherein the first and
second walls have a geometric center and wherein the first and
second stringers extend between the first and second walls at first
and second stringer locations, the first and second stringer
locations being equally spaced away from the geometric center.
11. The liquid holding tank of claim 1, wherein the first stringer
is comprised of first and second portions, each portion having an
annulus shaped face, the first and second portions being joined to
each other by the joining of the annulus-shaped faces.
12. A liquid holding tank comprising: a first sidewall; a second
sidewall, the first sidewall and the second sidewall having a first
sidewall thickness; a first stringer formed integrally with the
first and second sidewalls and extending between the first and
second sidewalls inside the liquid holding tank, the stringer being
a hollow tube having a tube sidewall, the tube sidewall having a
thickness substantially equal to the first thickness.
13. The liquid holding tank of claim 11, wherein the first and
second sidewalls and the stringer are molded at the same time and
wherein the hollow tube has a draft of between about two degrees
and twenty degrees.
14. The liquid holding tank of claim 11, wherein the first and
second sidewalls have corresponding centroids and wherein the
stringer is located at the centroids of the first and second
sidewalls.
15. The liquid holding tank of claim 9, wherein the stringer is
configured to exchange heat between air inside the stringer and at
least one of liquid and air inside the holding tank.
16. The liquid holding tank of claim 9, wherein the first portion
of a wall stiffener and the first holding tank wall are a unitary
structure.
17. An assembly of reinforced liquid holding tanks, the assembly
comprising: first and second reinforced liquid holding tanks, each
tank having first and second opposing side walls, the first and
second liquid holding tanks being adjacent to each other such that
the second side wall of the first liquid holding tank is adjacent
to, the first side wall of the second tank; each reinforced liquid
holding tank being comprised of: a first holding tank wall; a
second holding tank wall substantially parallel to the first
holding tank wall and laterally separated from the first holding
tank wall by a first separation distance; and a wall stiffener
extending between and attached to both the first and second
substantially vertical holding tank walls, the wall stiffener being
configured to maintain the tank width separation distance, at least
where the wall stiffener is attached to the first and second
holding tank walls.
18. The assembly of reinforced liquid holding tanks of claim 16,
further comprising a third reinforced liquid holding tank having
first and second opposing side walls, such that the first wall of
the third tank is adjacent to and in contact with the second wall
of the second tank.
19. The assembly of reinforced liquid holding tanks of claim 16,
wherein the wall stiffener in each tank is hollow and the
stiffeners in each tank are aligned.
20. A liquid dispenser comprising: a refrigerated cabinet having an
interior width defined by a separation distance between first and
second cabinet walls; and first and second reinforced liquid
holding tanks located between the first and second walls, each tank
having first and second opposing side walls, the first and second
liquid holding tanks being configured to be placed adjacent to each
other and inside the refrigerated cabinet such that the second side
wall of the first liquid holding tank is adjacent to, and in
contact with, the first side wall of the second tank; each
reinforced liquid holding tank being comprised of: a first holding
tank wall having a smooth exterior surface; a second holding tank
wall, which is configured to be substantially parallel to the first
holding tank wall and, laterally separated from the first holding
tank wall by a first separation distance and which also has a
smooth exterior surface; and a hollow wall stiffening tube
extending integrally formed with the first and second holding tank
walls and extending between them, the hollow wall stiffening tube
being configured to maintain a separation distance of the walls, at
least where the wall stiffener is attached to the first and second
holding tank walls, at least when a liquid is inside the holding
tank.
21. The liquid dispenser of claim 20, wherein a first hollow wall
stiffening tube in the first tank is aligned with a second hollow
wall stiffening tube in the second tank, the aligned wall
stiffening tubes configured to allow air to flow between the first
and second cabinet walls and configured to enable the first and
second liquid holding tanks to move vertically relative to each
other when the tanks are holding liquid.
Description
BACKGROUND
[0001] This application relates to liquid holding tanks having one
or more relatively thin, planar side walls. More particularly, this
invention relates to liquid holding tanks made of thin and flexible
materials, the shapes of such tanks being reminiscent of
rectangular parallelepipeds.
[0002] As used herein, a parallelepiped is considered to be a
volume or body bounded by four rectangles and two parallelograms. A
rectangular parallelepiped, however, is a parallelepiped, all six
faces of which are rectangles or substantially rectangular. A
rectangular parallelepiped is also considered to be a right prism,
the bases of which (top and bottom surfaces) are parallelograms. A
cube is a rectangular parallelepiped because it is a volume or body
bounded by six identical squares, the squares being rectangles.
[0003] A problem with holding tanks having thin, flat side walls is
that such walls tend to bow outwardly when the tank contains liquid
because of the distributed force exerted on the walls by the
liquid. As the level of the liquid in the tanks rises, the outward
deflection of the walls increases. Outward deflection of sidewalls
used in a rectangular, parallelepiped-shaped tank can make it
difficult to remove the tank from a space wherein the nominal tank
width is such that it just fits into the space.
[0004] The inward deflection of a tank's sidewalls can also be
problematic. In many liquid holding tanks, the level of the upper
surface of the liquid held in the tank is used to determine the
volume held in the tank. The height of the upper level also
determines the pressure at the bottom of the tank. Since most
liquid dispensers draw liquid from the bottom of the tank, the
height of the upper level will determine not only the flow rate
from the tank but also the apparent volume left in a tank. A liquid
holding tank with thin walls that are able to be held upright would
be an improvement over the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a front view of three liquid holding tanks;
[0006] FIG. 2 is a perspective view of the left-hand tank shown in
FIG. 1;
[0007] FIG. 3 is a cutaway view of the tank shown in FIG. 2 taken
along section lines 3-3;
[0008] FIG. 4 is a perspective view of the center tank shown in
FIG. 1;
[0009] FIG. 5 is a cutaway view of the tank shown in FIG. 4 taken
along section lines 5-5;
[0010] FIG. 6 is a perspective view of the right-hand tank shown in
FIG. 1;
[0011] FIG. 7 is a cutaway view of the tank shown in FIG. 6 taken
along section lines 7-7;
[0012] FIG. 8 is a front elevation view of a liquid dispenser
having holding tanks with reinforced sidewalls;
[0013] FIG. 9A is an isolated perspective view of a right-hand
portion of an alternate embodiment of a stringer;
[0014] FIG. 9B is a sectional view of a stringer shown in FIG. 9A;
and
[0015] FIG. 10 is a sectional view of the right-hand tank shown in
FIG. 6 with an alternate embodiment of a stringer.
DETAILED DESCRIPTION
[0016] FIG. 1 is a front view of an assembly of liquid holding
tanks 100. The assembly 100 is comprised of a left-hand tank 102, a
center tank 104, and a right-hand tank 106. Each tank has a top 108
and a bottom 110.
[0017] The left tank 102 and the right tank 106 both have a nominal
width W.sub.1, which is less than the nominal width W.sub.2 of the
center tank 104. All three tanks have the same nominal height, H.
All three tanks are the same nominal depth, which is considered to
extend into the plane of the page on which FIG. 1 is drawn.
[0018] The tanks' various dimensions and their resultant sizes are
design choices. The tanks' sizes shown in FIG. 1 are for
illustration purposes only.
[0019] All three tanks are considered to have "thin" sidewalls. The
side exterior surfaces are also smooth.
[0020] The term "thin" should be considered to mean between about
0.4 millimeters (0.015 inches) and about 4 millimeters (0.157
inches). The term "smooth" is considered herein to mean that the
exterior sidewall surfaces are without a projection, which if
between two tanks would prevent the two adjacent sides from making
contact with each other.
[0021] Although the sidewalls are thin and thus susceptible to
outward deflection or bowing when the tanks hold liquid and
susceptible to inward deflection or bowing because of manufacturing
defects or an object pressing inwardly, the side walls of the tanks
are reinforced to reduce or eliminate outward deflection when the
tanks hold liquid, and reduce or eliminate inward deflection or
deformation. The tanks shown in FIG. 1 are considered to be
"sandwiched" against each other because the sides of the tanks are
in contact with each other. They are nevertheless able to freely
slide against each other, including freely moving vertically
relative to each other. The left side outside sidewall of the left
tank 102 and the right side outside sidewall of the right tank 106
contacts adjacent surfaces of a refrigerated cabinet, not shown in
FIG. 1.
[0022] The physical contact between the smooth surfaces of the
tanks' sidewalls provides an enhanced heat transfer path between
the tanks, liquids contained inside them and the sidewalls of a
heated or cooled cabinet, when the tanks and a cabinet for them are
sized, shaped and arranged to provide an intimate contact between
them, as shown in the Applicant's co-pending patent applications.
One such application is application Ser. No. 12/885,659 filed on
Sep. 20, 2010, and which is entitled, "Dispenser for Liquids," the
entire contents of which are incorporated by reference. Another
application is application Ser. No. 13/169,339, filed Jun. 27, 2011
and which is entitled "Liquid Dispenser with Storage Tanks" The
entire contents of that patent application (application Ser. No.
13/169,339) are also incorporated herein by reference.
[0023] The tank assembly 100 is configured for use in a liquid
dispenser, by which is meant that the tanks are sized, shaped and
arranged to be used in a liquid dispenser. Examples of such
dispensers can be found in the aforementioned patent applications
incorporated herein by reference. The sidewalls are preferably thin
in order to reduce the tanks' cost but to also reduce their weight
while maximizing the volume of liquid they can hold in a relatively
small refrigerated cabinet.
[0024] FIG. 2 is a perspective view of the left-hand tank 102. The
left-hand tank 102 has a substantially planar front face or side
200, a substantially planar rear side or face 202 not visible in
FIG. 2, a substantially planar left side 204, not visible, and a
substantially planar right side 206. All four sides are
substantially planar, i.e., at least their exterior surfaces are
flat as well as smooth, and joined to each other by
stress-relieving, curved corner sections 208.
[0025] The tanks 102, 104 and 106 have substantially equal-sized
tops 108. The equal-sized tops 108 makes a tank re-filling task
equally convenient (or inconvenient), for each tank. Providing each
tank with an equal-sized top 108, however, requires the right-side
of the left-hand tank 102 to curve rightward near the tank's top.
It also requires the left side of the right-hand tank 106 to curve
leftward near the top.
[0026] Each tank shown in FIG. 1, including the left-hand tank
shown in FIG. 2 and FIG. 3 has a cover 210 that can also be
considered to be a top for a tank. The cover 210 is provided with a
hinged door 212, which allows the tank 102 to be refilled. The door
212 is attached to the cover 210 by a hinge and opens by rotation
around a hinge pin 214 "rotatably" attached to the cover 210.
[0027] The term, "rotatably attached" means that the door 212 is
attached to the cover 210 so that the door 212 can rotate along one
edge of the cover, about an axis, yet be effectively attached to
the cover 210. A hinge provides a rotatable attachment.
[0028] The front side or face 200, rear side or face 202, the left
side 204, and the right side 206 are considered herein to be walls.
As can be seen in the figure, the front wall 200 and the rear wall
202 are substantially parallel to each other as are the left wall
204 and the right wall 206. Minor deviations in the parallelism of
the sides are likely to exist at least because of manufacturing
tolerances.
[0029] Problematic outward deflection and problematic inward
deflection is eliminated or at least significantly reduced in
thin-walled liquid holding tanks, such as the tanks shown in FIG.
1, by providing sidewalls that oppose each other with sidewall
reinforcements or stiffeners. The sidewall stiffeners described
herein extend between the walls, but are located inside the
exterior surfaces of the sidewalls. They do not add or require a
projecting fastener outside the tank's sidewalls. The sidewall
stiffeners, which are referred to hereinafter as stringers, are in
tension when the tank holds liquid. The stringers help to hold the
walls rigid and upright, at least where they are attached to the
sidewalls, and thus maintain wall separation distance, at least
where they are attached to the sidewalls, when the tank holds
liquid.
[0030] Except for the cover 210, all four sidewalls, the stringers
and the bottom 110 are formed by rotational molding or
"roto-molding." Rotational molding is also known as spin casting
and "rotocasting." It is a process wherein a thin-walled, two-piece
mold is designed to be rotated about two perpendicular axes.
Rotational molding is able to produce hollow parts, including the
tanks 102, 104, 106 with side wall thicknesses as small as 0.4
millimeters. See, Serope Kalpakjian, et al., Manufacturing
Engineering and Technology, 501-502, Pearson Education, Inc.
(2010).
[0031] To mold the tanks using rotational molding, a premeasured
quantity of powered plastic material is placed inside a tank form
or mold. The mold is heated as it is rotated around the two
perpendicular axes. Rotation of the mold around the two axes
tumbles the plastic power against the mold. Depending on the type
of plastic, the heat can either fuse the powder or it can melt and
coat the mold surfaces. The material in the mold eventually
solidifies whereupon the mold is opened and the molded piece
removed from the mold.
[0032] By forming the tank using rotational molding, the stringers
are formed to extend between the sidewalls and are formed
seamlessly, i.e., without seams. As used herein, a seam exists
where two pieces are joined together and should not be confused
with a mold mark And, since the material from which the tank and
its stringers are formed is continuous or seamless, a stringer is
formed integrally with the sidewalls during the spin molding
process. A stringer is thus considered herein to be part of, or
formed with the sidewalls. The rotational molding process also
enables the stringers to be formed inside the tank without a
projection or protuberance above the outside surfaces of the
sidewalls as a thru-bolt might require. The thickness of the
sidewalls and the stringers formed with them are also the same or
substantially the same. The stringers do not require any sort of
localized sidewall mounting boss or reinforcement that a thru-bolt
recessed into a sidewall might require.
[0033] In FIG. 2, the left wall 204 and the right wall 206 are
reinforced and helped to stay vertical by at least one stringer
that extends between the sidewalls 204 and 206. FIG. 2 shows two
stringers 220-1 and 220-2. They are formed during the same spin
casting process during which the sidewalls 204 and 206 are formed.
The stringers are thus part of the sidewalls 204 and 206 that
oppose each other. The stringers 220-1 and 220-2 are hollow and
because they are formed during the spin casting process, they are
as thin as the sidewalls but nevertheless significantly reduce
outward and inward deflection of the sidewalls 204 and 206.
[0034] FIG. 3 is a cross sectional view of the tank 102 shown in
FIG. 2 taken through section lines 3-3. FIG. 3 depicts the
left-side tank shown in FIG. 1. The outside surfaces 300 of the
sidewalls 204 and 206 are depicted as being upright or at least
substantially upright, vertical or at least substantially vertical,
and planar or at least substantially planar, i.e., without a
projection such as a thru-bolt 301 that would be required if the
sidewalls were to be reinforced or stiffened by such a structure,
and smooth.
[0035] The stringers 220-1 and 220-1 are essentially hollow
elongated cylinders or tubes. They can be seen to be "similar" to
each other. Except for their locations in the side walls 204 and
206, the second stringer 220-2 has the same or substantially the
same attributes of the first stringer 220-1.
[0036] While the stringers 220-1 and 220-2 are essentially tubes,
which have themselves a sidewall, both stringers have
cross-sectional shapes reminiscent of a venturi, when viewed along
section lines 3-3. The stringers have a relatively large inside
diameter at the tank sidewalls 204, 206. The stringers' diameter
narrows continuously throughout the length of a tapered region 304
of the stringers. The inside and outside diameters of the stringers
narrows to a constriction, also referred to as an inflection point
306 where the stringer's inside diameter is most narrow. The
relatively large taper of the stringers that imbues them with a
venturi-like cross sectional shape is attributable to the draft
used in the mold from which the tank is made. The larger the draft
used in a mold the easier it is to remove a molded part. The draft
of the stringer is preferably between about two degrees and twenty
degrees to enable the molded tank 102 to be easily removed from the
mold in which it is formed.
[0037] As used herein, the terms "draft," "draft angle" and "taper"
refer to an angle of a surface relative to a reference, typically
vertical or horizontal, which is provided to a mold to enable of a
part from the mold after the part has solidified. The ease with
which a molded object can be removed from a mold depends in part on
the draft angle used in the mold. Draft angles can be small for
molded metals, e.g., slightly greater than one (1) degree, however,
draft angle are usually larger for molded plastics. The draft angle
us usually measured with respect to a vertical line or axis but can
be measured relative to a horizontal line or other reference
line.
[0038] Those of ordinary skill in the art will recognize that the
tanks can be made from separately-molded tank halves that are
mirror "images" of each other or substantially mirror images of
each other. Tanks formed from separate halves are joined together
after being molded by heating or an adhesive.
[0039] A hollow stringer 220 reduces the weight and thus the cost
of the tanks but an additional benefit of a hollow stringer is that
air can flow through the open space inside the hollow stringer. Air
inside a stringer can enhance heat transfer into or out of a liquid
inside the tank. By way of example, air inside a stringer 220 that
is cooler than the stringer material 309, or that is cooler than
liquid inside the tank will absorb heat. Air in a stringer 220 that
is warmer than the stringer material 309 or warmer than liquid in
the tank will transfer heat into the stringer and thus into the
liquid in the tank. A stringer is thus considered to also be a heat
exchanger.
[0040] Despite the fact that the stringers 220-1 and 220-2 are
integrally formed with the sides, are continuous and seamless, for
purposes of claim construction, the stringers 220-1 and 220-2 are
considered herein to have opposing first and second ends, 310 and
312 respectively. The lower or first stringer 220-1 has a first end
310 located at but also forming part of the left-hand wall 204; a
second end 312 is located at but also forming part of the
right-hand wall 206. Similarly, the upper or second string 220-2
has a first end 310 located at and forming part of the left-hand
wall 204 and a second end 312 located at and forming part of the
right-hand wall 206. The stringers are preferably formed to be
substantially orthogonally, i.e., at a right angle to the sidewalls
that they reinforce.
[0041] In FIG. 2 and FIG. 3 the stringers 220-1 and 220-2 are
vertically separated from each other. The distance between the
stringers is considered to be a stringer separation distance 312.
The stringer separation distance is selected to keep the center
line 314 of each stringer 220 equidistant or substantially
equidistant in a vertical direction, i.e., above or below, a
geometric point or location on the sidewalls 204 and 206, which is
considered herein to be a "centroid" for each side 204 and 206.
[0042] The geometric center of the sides, i.e., the centroid in
each wall, is identified by reference numeral 230. The stringer
separation distance 312 is considered herein to be the distance
between a geometric axis or center line 314 of each of the two
stringers. In one embodiment of a holding tank with
internally-reinforced sidewalls, the wall stiffener is located
between the sidewalls at the centroids of each wall. In preferred
embodiments, wherein multiple stiffeners are used, the stiffeners
can be spatially separated from each other and located in the
sidewalls to be equidistant or substantially equidistant from the
centroid 230 in order to equalize the retention force provided by
each stringer. In an alternate embodiment, two or more stringers
are horizontally separated from each other in the sidewalls to be
at the same level or distance from the bottom 110 of the tank but
on either side of the centroid 230. In yet another embodiment
having four stringers, two of the four stringers being located as
shown in FIG. 3, two other stringers being laterally separated from
each other on either side of the centroid 230 and at the same
distance from the bottom 110.
[0043] FIG. 4 is a perspective view of the center tank 104 shown in
FIG. 1. As with the tank shown in FIG. 3, the walls are upright,
substantially planar and have exterior surfaces that are
substantially smooth. The center tank 104 has a front wall 400 and
an opposing rear wall 402. Similarly it has a left-hand wall 404
and an opposing right-hand wall 406. The four walls, 400, 402, 404
and 406 are substantially planar and joined to each other by
stress-relieving, curved corner sections 408. The opposing left and
right sidewalls 404 and 406 are held substantially upright with
smooth exterior surfaces 410. Their outward and inward deflection
is reduced or eliminated by two stringers 440-1 and 440-2, both of
which are hollow to allow air to flow in and through them, both of
which extend between the two opposing sidewalls 404 and 406. As
with the stringers 220-1 and 220-2 depicted in FIGS. 2 and 3, the
stringers 440-1 and 440-2 are also formed together with the
sidewalls and are thus continuous and seamless with the sidewalls,
i.e., the stringers are formed integrally with the rest of the
tank.
[0044] The center tank 104 is shown in cross section in FIG. 5,
which is a cross section through section lines 5-5. The center tank
104 is also formed by rotational molding. As with the stringers
used in the left-hand tank, the stringers 440 used in the center
tank are preferably located in the sidewalls so that they are
vertically above and below and equally separated from what is
considered herein to be a centroid or geometric center 430 for the
left side wall 404 and the right-hand wall 406. Alternate
embodiments include a tank with laterally or horizontally separated
stringers located on either sides of the centroid 430.
[0045] As used herein, the centroid is considered to be a geometric
center of the side walls. The actual location of the centroid will
vary depending upon the geometry of the sidewalls.
[0046] For purposes of claim construction, the walls of each tank
are thin but nevertheless have two opposing surfaces referred to as
"interior" and "exterior" surfaces. As shown in FIG. 5, which is a
cross-sectional view of the middle tank 104 shown in FIG. 4, a
first interior surface 450 faces into the tank; a second exterior
surface 452 faces outwardly. Both surfaces are preferably
smooth.
[0047] The right-side wall 406 is also thin and it too has opposing
surfaces 454 and 456. A first, interior surface 454 of the
right-side wall 406 faces into the tank; a second opposing exterior
surface 456 is smooth and faces outwardly.
[0048] A first portion 458 of a wall stiffener or "stringer" 440
extends into the tank 104 from the left-side wall 404. The first
portion 458 is tapered and has a length 460 that extends into the
interior 462 of the tank 104. A second portion 464 of the stiffener
440, which is also tapered, extends inwardly from the interior
surface 454 of the right side wall 406. The second portion 464 has
its own length 466, which is preferably equal to the first length
460. The length 460 of the first portion 458 is measured from the
vertical, internal center line 470 of the tank 104 to the internal
surface 450 of the left side 404. The length 466 of the second
portion 464 is measured from the internal center line 470 to the
internal surface 454 of the right side 406. While the lengths 460
and 466 are depicted in FIG. 5 as being equal or at least
substantially equal, the lengths of the portions of the stringers
can in fact be different from each other. As with the stringers
220-1 and 220-2, air can flow into and through the stiffeners 440-1
and 440-2 shown in FIGS. 4 and 5.
[0049] FIG. 6 is a perspective view of the right-hand tank 106
shown in FIG. 1. As with the other two tanks, the right-hand tank
106 has four walls, 600, 602, 604 and 606, joined to each other by
stress-relieving curved sections 608. The front wall 600 and the
opposing rear wall 602 are substantially planar, and parallel to
each other. The left wall 604 and the right wall 606 are planar,
have exterior surfaces 610 that are smooth and which are
substantially parallel to each other. Two stringers 660-1 and 660-2
that extend inwardly from the sidewalls resist outward and inward
deflection of the sidewalls when the tank is filled or partially
filled with liquid, not shown.
[0050] Reference numeral 630 identifies the location of a centroid
or geometric center of the sidewalls 604 and 606. The stringers
660-1 and 660-2 extend inwardly from the left-hand wall 604 and
inwardly from the right-hand wall 606, as they do with the other
two tanks described above.
[0051] The right-hand tank 106 is shown in cross section in FIG. 7.
As with other tanks described above, the tank 106 shown in FIGS. 6
and 6 and the included stringers 660-1 and 660-2 are formed by
rotational molding. The stringers 660-1 and 660-2 are preferably
located in the sidewalls 604 and 606 so that they are above and
below and equally separated from a centroid 630 for the left side
wall 604 and the right-hand wall 606, in order to evenly distribute
the sidewall retaining forces they provide to the sidewalls.
[0052] For purposes of claim construction, two more
sidewall-reinforced tanks, such as the three sidewall-reinforced
tanks 102, 104 and 106 shown in FIG. 1, are considered herein to be
an assembly of reinforced liquid holding tanks. Each tank has at
least two opposing sidewalls, the exterior surfaces of which are
preferably smooth, nominally parallel to each other and separated
from each other by a separation distance substantially equal to the
width, w, of the tank. The sidewalls of a tank are kept
substantially parallel to each other by at least one wall stiffener
that extends inwardly from, and between the two opposing sidewalls.
The stiffener is a structure that is formed as part of the opposing
sidewalls or which is attached to or joined to the sidewalls such
that the stiffener does not require a protuberance above the
exterior surface of a tank sidewall providing the exterior surface
of the sidewall with a smooth surface. The fact that the sidewalls
are smooth and kept vertical or substantially vertical reduces and
can even eliminate friction between adjacent tanks in a cabinet.
That the sidewalls are smooth can also enhance heat transfer
between tanks, the sidewalls of which are in contact with each
other or with the interior sidewalls of a temperature-controlled
cabinet such as a refrigerator.
[0053] A liquid dispenser with liquid holding tanks having
reinforced sidewalls as described above, the tanks of which are
able to move vertically with respect to each other even while they
contain liquid, can be realized by combining the tanks described
above with a refrigerated liquid dispenser as described in the
Applicant's co-pending patent application having U.S. patent
application Ser. No. 13/169,339, filed Jun. 27, 2011 and which is
entitled "Liquid Dispenser with Storage Tanks" The entire contents
of that patent application (application Ser. No. 13/169,339) are
therefore incorporated herein by reference. When two or more
reinforced tanks as described above are used in a liquid dispenser,
such as the one described in U.S. patent application Ser. No.
13/169,339, one advantage is that the friction between the sides of
adjacent tanks is reduced because the sides of the tanks are kept
upright. An additional advantage is realized by the stringers'
facilitating heat transfer between air inside the hollow stringers
of the different tanks that are aligned with each other and
temperature-controlled sidewalls of a cabinet. Aligned hollow
stringers form a heat exchanger, which is effectively located
inside the tank and effectively immersed in liquid in the tank.
[0054] In FIG. 8, reference numeral 800 identifies the liquid
dispenser identified by reference numeral 100 in the aforementioned
co-pending application Ser. No. 13/169,339. A left-hand tank 802, a
center tank 804 and a right-hand tank 806 are provided with hollow
stringers, 808, 810 and 812 respectively and which are aligned to
each other vertically and horizontally (into and out of the plane
of the figure) such that air can flow between them. Heat energy in
the air that is inside the stringers can be absorbed into sidewalls
814 and 816 when such sidewalls are refrigerated. Conversely, heat
energy in heated sidewalls 814 and 816 can be transmitted into the
air inside the stringers from which it will flow into the tanks.
The stringers 808, 810 and 812 act as heat exchangers with respect
to air and liquid in the tanks 802, 804 and 806. In FIG. 8, heat
energy is represented by small arrows drawn to show heat being
dissipated into air inside the stringers 808, 810 and 812. Heat
energy is also depicted as flowing through sidewalls of the tanks
into the sidewalls 814 and 816 of the dispenser 800.
[0055] While the preferred embodiment of a tank and stiffener is
formed by rotational molding, in an alternate embodiment, a tank
can be formed from joined-together molded halves. In such a tank,
each of the halves has a stiffener embodied as cone-shaped,
inwardly-directed projection, such as the cone-shaped projection
900 depicted in FIG. 9 as extending inwardly from a tank sidewall
902. The projection 900 is tapered 904 with a flange 906 at the
distal end 908. The flange 906 provides a surface that can be
joined by heat or adhesive to a mating surface on a similar
projection from the opposite side of the tank. Alternate and
equivalent embodiments include non-cone shaped inwardly-directed
projecting portions. Alternate and equivalent embodiments also
include inwardly-directed projections that are of unequal
lengths.
[0056] FIG. 10 depicts a cross sectional view of yet another
embodiment of a thin-walled rectangular liquid holding tank 1000.
The particular tank 1000 shown in FIG. 10 is shaped to be used on
the right-hand side of the tank assembly shown in FIG. 1. A top
portion 1002 of the left-hand side 1004 of the tank 1000 has an
elbow or curve 1006 that conforms to the shape of the right-hand
side of the center tank 104.
[0057] Unlike the tanks described above, the tank 1000 shown in
FIG. 10 is molded without a stiffener or stringer. Stated another
way, the stringers in the tank shown in FIG. 10 are not formed as
part of the tank side walls during a molding process. Solid or
semi-solid, cylindrical wall stiffeners 1008 and 1012 are instead
added to the interior of the tank 1000 after the tank 1000 is
molded. The after-molding stringers are preferably added to the
tank by being placed therein through the top 1003 of the tank,
which can be removed. One or more sidewall stiffeners are then
placed inside the tank and attached to the sidewalls.
[0058] In FIG. 10, a top stiffener 1008 has a length L that fits
just inside the side walls 604 and 606. The top stiffener 1008 is
attached to the sidewalls 604 and 606 using a common mechanical
fastener such as a screw 1010.
[0059] A bottom stiffener 1010 having the same length as the top
stiffener 1008 is attached to the side walls 604 and 606 by either
by a localized heating of the stiffener 1010 and sidewall, an
ultrasonic weld 1014 between the stiffener and sidewall or an
adhesive 1016 or both welding and an adhesive or heat and an
adhesive.
[0060] Whether the tanks are formed by rotational molding or by
assembling the tanks in halves or by other methods, the wall
stiffeners described above are considered herein to be tubes. A
tube need not have a circular cross section. A tube that forms a
wall stiffener can have non-circular cross-sectional shapes, the
tube cross-sectional shape being the cross-sectional shape
orthogonal to the center line or axis 314, as shown in FIG. 3.
[0061] The wall stiffeners referred to above as a stringer,
provides an internally-located reinforcement to sidewalls of a
holding tank for liquids. The stringers in the embodiments depicted
in FIGS. 1-9 are considered to be connected or attached to the
sidewalls, even though the stringers formed by rotational molding
are integrally formed as part of the sidewalls during a molding
process.
[0062] The stringers are considered herein as "extending" between
the walls. They maintains a tank width by opposing outward-directed
force caused by liquid inside the tank and inward deflection that
can be caused by manufacturing differences or outward forces
applied to the tank sidewalls. When the assembly of tanks is
disposed inside of a cabinet, such as a refrigerated dispensing
cabinet described in the co-pending patent application identified
above, or as shown in FIG. 8, the reinforced sidewalls of the
liquid holding tanks allow the tanks to be individually refilled or
emptied without having them deform in response to liquid inside one
or more of them. The reinforcement also helps keep the sidewalls
rigid and as shown in the figures, upright, so that measurement of
the volume inside the tanks determined by the level of the liquid
can be made more accurately.
[0063] The foregoing description is for purposes of illustration
only. The true scope of the invention is set forth in the following
claims.
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