Note: Descriptions are shown in the official language in which they were submitted.
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WATER HEATER AND METHOD OF MOUNTING A HEATING ELEMENT IN A
WATER HEATER
FIELD OF THE INVENTION
[0001] The invention relates generally to a method and apparatus for mounting
heating
elements in a water heater. More specifically, the invention relates to a
method and apparatus
for assuring a particular orientation of the heating element within the water
heater.
BACKGROUND
[0002] A storage-type water heater typically comprises a permanently enclosed
water
tank, a cylindrical shell coaxial with and radially spaced apart from the
water tank to fonn an
annular space between the outer wall of the water tank and the inner wall of
the shell, and
insulating material in at least a portion of the annular space for providing
tllermal insulation
to the water tank. The water tank has various appurtenances such as inlet,
outlet, and drain
fittings. Additionally, the water heater is provided with a water heating and
temperature
control system. In electric water heaters, the water heating and temperature
control system
includes one or more electrical resistance heating elements.
SUMMARY
[0003] The water tai-Ac has tank characteristics that are used in determining
the thermal
profile of the tank. The tank characteristics may include, but are not limited
to, tank
diameter, tank height, tank storage capacity, etc. The tank characteristics
determine heating
convection current flow patterns within the tank that create different
temperature water strata
layers in the tank. Another characteristic that determines heating convection
current flow
patterns is the placement and position of the heating element in the tank.
Some heating
element positions improve the current flow patterns in the tank. It is thus
desirable to mount
the heating element within the tank in a position that maximizes thecurrent
flow patterns
within the tanlc to increase the efficiency of the water heater.
[0004] Accordingly, and in one embodiment, the invention provides a water
heater that
rests in relation to the floor. The water heater includes a water tank having
a wall, a
mounting device coupled to the wall of the water tank, and a heating element
coupled to the
mounting device. The heating element includes a greatest cross-sectional area
and cooperates
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with the mounting device such that coupling the heating element to the
mounting device
ensures the greatest cross-sectional area of the heating element is level with
respect to the
floor.
[0005] In some embodiments, the mounting device is threaded and the heating
element
includes mating threads. In other embodiments, at least one of the heating
element and the
wall of the tank includes an identification mark such that aligning the
identification mark in a
predetermined position results in the greatest cross-sectional area of the
heating element
being level with respect to the floor. In other embodiments, the mounting
device includes a
mounting flange and the heating element includes a heating element flange that
cooperates
with the mounting flange. In yet other einbodiments, the water heater includes
a resilient
gasket placed between the cooperating mounting flange and heating element
flange, and a
compression element is coupled to the mating flanges, compressing the gasket
therebetween
to form a water-tight seal between the mounting flange and heating element
flange.
[0006] The invention also provides for a method of installing a heating
element in a fluid
heating apparatus. The method includes providing a fluid tank within the fluid
heating
apparatus, the fluid tank having a wall, coupling a mounting device to a wall
of the fluid tank,
and coupling a heating element to the mounting device to ensure that the
greatest cross-
sectional area of the heating element is level with respect to the floor.
[0007] Other features and advantages of the invention will become apparent to
those
skilled in the art upon review of the following detailed description, claims,
and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig. 1 is a sectional view of a water heater embodying aspects of the
invention.
[0009] Fig. 2 is a top view of a heating element for use in the water heater
of Fig. 1.
[0010] Fig. 3 is a side view of the heating element of Fig. 2.
[0011] Fig. 4 is a top exploded sectional view of the water heater of Fig. 1
illustrating the
heating element coupled to a mounting device.
[0012] Fig. 5A is an end view of a single-start threaded connector.
[0013] Fig. 5B is a side view of the threaded connector of Fig. 5A.
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[0014] Fig. 6A is an end view of a two-start threaded connector.
[0015] Fig. 6B is a side view of the threaded connector of Fig. 6A.
[0016] Fig. 7A is an end view of a three-start threaded comlector.
[0017] Fig. 7B is a side view of the threaded connector of Fig. 7A.
[0018] Fig. 8A is an end view of a four-start threaded connector.
[0019] Fig. 8B is a side view of the threaded connector of Fig. 8A.
[0020] Fig. 9 is an end view of the heating element of Fig. 2, illustrating an
identification
mark.
[0021] Fig. 10 is a partial exploded perspective view of another construction
of a water
heater embodying aspects of the invention.
[0022] Fig. 11 is an enlarged view taken along line 11-11 of Fig. 10.
[0023] Fig. 12 is an enlarged view of an alternate mounting device capable of
being used
with the water heater of Fig. 10.
DETAILED DESCRIPTION
[0024] Before any embodiments of the invention are explained in detail, it is
to be
understood that the invention is not limited in its application to the details
of construction and
the arrangement of components set forth in the following description or
illustrated in the
following drawings. The invention is capable of other embodiments and of being
practiced
or of being carried out in various ways. Also, it is to be understood that the
phraseology and
terminology used herein is for the purpose of description and should not be
regarded as
limiting. The use of "including," "comprising," or "having" and variations
thereof herein is
meant to encompass the items listed thereafter and equivalents thereof as well
as additional
items. The terms "connected," "coupled," and "mounted" and variations thereof
herein are
used broadly and, unless otherwise stated, encompass both direct and indirect
connections,
couplings, and mountings. In addition, the terms connected and coupled and
variations
thereof herein are not restricted to physical and mechanical connections or
couplings.
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[0025] Fig. 1 shows a sectional view of an electric water heater 10 comprising
a vessel.
With reference to Fig. 1, the vessel is defined as one of an enclosed water
tank 11 or a shell
12 surrounding the water tank 11. Foam insulation 13 fills the annular space
between the
water tank 11 and the shell 12. A water inlet line or dip tube 14 and a water
outlet line 15
enter the top of the water tank 11. The water inlet line 14 has an inlet
opening 22 for adding
cold water near the bottom of the water tank 11. The water outlet line 15 has
an outlet
opening 24 for withdrawing hot water from near the top of the water tank 11.
The water
heater 10 is configured to rest on a support surface, such as the floor 25. In
the illustrated
construction, the water heater 10 includes an axis A that is substantially
perpendicular to the
floor 25.
[0026] A heating element 16 extends through the wall of the water tank 11. In
the
illustrated embodiment, the heating element 16 is an electric resistance
heating element.
However, other types of heating elements can be used. The mounting of the
heating element
16 to the wall of the water tank 11 will be described in more detail below.
[0027] The temperature control circuitry controls the heating of the water.
The
temperature control circuitry includes a controller (in control box 17), a
teinperature sensor
assembly 18, and the heating element 16. In one construction, the temperature
control
circuitry includes a burst control circuit for providing power to the
resistance heating element
in bursts. The details of a burst control circuit are described in U.S. Patent
No. 6,633,726,
entitled METHOD OF CONTROLLING THE TEMPERATURE OF WATER IN A WATER
HEATER, issued October 14, 2003, the entire disclosure of which is
incorporated herein by
reference. However, the temperature control circuitry can use other
circuitries and other
methodologies for heating the water.
[0028] In some constructions, the temperature control circuitry in control box
17 includes
a programmable real time clock. Peak or off-peak energy demand periods or
vacation
operation cycles are programmed into the control cycle for the heating
element.
Additionally, a pressure sensor, temperature sensor, mineral deposit sensor
andlor sensor for
detecting the presence of water could be added. In one method of operation of
the water
heater 10, the control circuit is programmed to disconnect power from the
heating element
when predetermined conditions or limits are detected.
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[0029] Referring again to Fig. 1, the temperature sensor assembly 18 is
coupled to the
outer wall of the water tank 11 to sense the temperature of water in the tank
11. The
temperature sensor assembly can include one or more thermistors for sensing
the temperature
of the water in the tank 11. When multiple thermistors are used, the
thermistors are placed
throughout the tank to measure water temperature at a plurality of locations,
and the output of
the thermistors can be averaged. However, the temperature sensor assembly can
use other
types of temperature sensors and can be simply a single sensor.
[0030] The temperature sensor assembly 18 is connected to the controller, for
example,
by an electrical wire 19. The controller is a known control system in the art
that is in
communication with the heating element 16 and the temperature sensor assembly
18 and
generates a signal controlling the heating element in response to the
temperature sensed by
the sensor assembly 18. The controller can include an integrated circuit, a
programmable
device, discrete circuit elements, a processor and memory that are software
driven, and
similar components. The controller may include a switching element (not
shown), such as a
thyristor or a triac, to selectively power the heating element.
[0031] Electric alternating current (A.C.) power is supplied to the water
heater 10 through
line 20. A customizable operator interface (not shown) can be mounted on the
outside of the
water heater to permit communication with the controller and provides security
protected
access for control of the heating element. The operator interface may be
operable to provide
direct or remote control of the heating element.
[0032] Fig. 2 illustrates the heating element 16 in more detail. As
illustrated in Fig. 2, the
heating element 16 of the illustrated embodiment is substantially U-shaped
when viewed
from the top. However, it is understood that any shape of heating element,
such as a round or
circular loop, a flat helix design, a serpentine pattern, or other shapes, can
be used with the
water heater 10. The heating element 16 includes a greatest cross-sectional
area 26, best
shown in Fig. 2.
[0033] With reference to Figs. 2-4, the heating element 16 also includes a
heating
element flange 28 that mates with a mounting flange 30 of a mounting device 32
coupled to a
wall of the water tank 11. As used herein, the term "flange" means not only a
traditional
mechanical flange, but any mount on the heating element that mates with a
mount on the
mounting device to assist in coupling the heating element 16 to the tank 11.
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[0034] The heating element flange 28 includes threads 34. The heating element
16
further includes an electrical connector portion 36 that includes electrical
contacts 40 (also
shown in Fig. 9) that are in communication with the controller for controlling
the heating of
the water in the tank 11.
[0035] A gasket is also coupled to the heating element 16. In the illustrated
embodiment,
the gasket is a compressible 0-ring 44 that can be made of any temperature-
tolerant resilient
material, such as neoprene, silicone, rubber, etc. It is understood that the
gasket can be of any
configuration and/or material that is capable of providing a resilient seal
between the heating
element 16 and the mounting device 32. The function of the 0-ring 44 will be
discussed in
more detail below.
[0036] As mentioned above, a mounting device 32 is coupled to a wall of the
water tank
11. The mounting device 32 is generally welded to a wall of the tank 11 and is
configured to
receive the heating element 16. As shown in Fig. 4, the mounting device 32
includes the
mounting flange 30 having threads 48 that mate with the threads 34 of the
heating element
16. Threading the heating element 16 into the mounting device 32 also
functions to compress
the 0-ring 44 therebetween to fonn a water-tight seal between the mounting
device 32 and
the heating element 16.
[0037] In the illustrated construction, the threads 48 of the mounting flange
30 and the
mating threads 34 of the heating element 16 are multi-lead or multi-start
threads. Figs. 5A
and 5B illustrate an end view and a side view of a single-start threaded
connector 50. When
looking at a single-start threaded connector 50 in an end view, the threads
form an offset
circular shape. In contrast, with reference to Figs. 6A, 7A, and 8A, a two-
start threaded
connector 52 will have a somewhat oval or football shape in an end view, a
three-start
threaded connector 54 will have a tri-oval shape, and a four-start threaded
connector 56 will
have a four-cornered shape in the end view.
[0038] The more starts or leads that the threaded connector has, the faster
the mating
threads will travel along the threaded connector. This occurs because using
multiple starts
increases the number of starting points a thread will engage in a mating part
with fewer
degrees of rotation, increasing the thread contact area (when compared to a
thread with the
same lead but using a single start). This can be illustrated in the following
way: if one places
a pencil in a thread groove 58 of a single-start threaded connector 50 and
rotate the threaded
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connector 360 (i.e., one full revolution), the mark 601eft by the pencil in
the groove will end
in the adjacent thread groove 58 (see Fig. 5B). In contrast, placing a pencil
in a groove 58 of
a two-start threaded connector 52 and rotating the threaded connector 52 one
full revolution
will result in one groove 58 existing between the ends of the mark 60 (see
Fig. 6B). Two
grooves 58 will exist between the ends of the mark 60 made on a three-start
threaded
connector 54 (see Fig. 7B), and so on. Utilizing multi-start threads in the
illustrated
construction functions to speed the installation of the heating element 16
into the mounting
device 32, as well as making adjustment of the heating eleinent 16 during the
threading
process more precise. However, it is understood that single-start threads
could be used as the
mating threads 34.
[0039] In some constructions, the heating element 16 also includes an
identification mark
that assists a user in coupling the heating element 16 to the mounting device
32 when a
particular heating element orientation within the tank 11 is desired. As
illustrated in Fig. 9,
the identification mark is an arrow 64 that indicates a particular heating
element orientation.
The arrow 64 is pointed upward with respect to the floor 25, and may include
the word "Up"
inside the arrow to indicate to a person installing the heating element 16 in
the tank 11 what
the final orientation of the heating element 16 should be. It is understood
that in other
constructions utilizing an identification mark, other types of marks could be
used, so long as
the identification mark assists in the installation of the heating element to
obtain the desired
final orientation of the heating element 16 in the tank 11. It is also
understood that in some
constructions, an identification mark may also be placed on the outside of the
wall of the tank
11 instead of, or in conjunction with, the identification mark on the heating
element for the
same purpose. For example, the identification mark on the heating element
could be a
straight line mark or the bottom half of a shape (such as a semi-circle) that
needs to be
matched with a mating mark (e.g., a second straight line or semi-circle) found
on the water
tank 11 to obtain the desired final orientation of the heating element 16.
[0040] In the illustrated constructions, the desired final orientation of the
heating element
16 within the tank 11 is such that the greatest cross-sectional area 26 of the
heating element
16 is level with respect to the floor 25, as shown in Figs. 1 and 4. As used
herein, the term
"level" means that the heating element 16 is at least substantially parallel
to the ground in an
upright water heater such as illustrated in Fig. 1 and that slight variations
from absolute level
are possible due to mechanical tolerances and slight variations in the floor
and still fall within
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the definition of "level." Put another way, the greatest cross-section 26 of
the heating
element 16 is preferably substantially perpendicular to the axis A of the
water heater 10.
[0041] The level orientation results in better thermal transfer from the
heating element 16
to the water in the tank 11 because the greatest cross-section 26 of the
heating element 16 is
exposed to convection currents within the water, thereby improving the
efficiency of the
convection currents. This results in an improved recovery time for the water
heater 10, and
increases the overall efficiency of operation of the water heater 10.
[0042] Figs. 10 and 11 illustrate an alternate construction of a inounting
device 70.. Like
reference numerals will be given to like parts as appropriate.
[0043] As shown in Figs. 10 and 11, the heating element 16 includes a heating
element
flange 74 that mates with a mounting flange 78 of the mounting device 70. Each
of the
heating element flange 74 and mounting flange 78 have a plurality of apertures
82, 84 that
align with each other when the heating element flange 74 is coupled to the
mounting flange.
The apertures are configured to receive a fastener 86 therethrough. It is
understood that the
fastener could be a screw, a bolt, a weldment, a rod, or any other appropriate
mechanical
fastening system. In the illustrated construction, five apertures 82, 84 are
spaced at points
around the flanges to receive up to five fasteners 86 therethrough to couple
the heating
element 16 to the tank 11. However, it is understood that any number of
apertures and
fasteners can be used to couple the heating element 16 to the tank 11.
[0044] A circular resilient gasket 90 is also provided to fit between the
heating element
flange 74 and mounting flange 78. The gasket 90 includes apertures 94 that
align with the
apertures 82, 84 in the flanges. The heating element 16 is coupled to the
mounting device by
aligning the apertures 82, 84 in the heating element flange 74 and mounting
flange 78 with
the apertures 94 in the gasket 90. Once the apertures are aligned, the
fasteners 86 are placed
through the apertures to couple the heating element 16 to the tank 11. The
fasteners 86 are
tightened to compress the gasket 90 between the flanges, forming a water-tight
seal between
the heating element 16 and the tank. In this way, the fasteners 86 function as
a compression
element, compressing the gasket 90 to form the seal.
[0045] The pattern of apertures 82, 84, 94 in the heating element flange 74,
mounting
flange 78, and gasket 90, respectively, function as an identification mark to
assist in the
installation of the heating element 16 to obtain the desired level orientation
of the heating
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element 16 discussed in detail above. If the pattern of apertures 82 on the
heating element
flange 74 is matched to the pattern of apertures 84 on the mounting flange 74
when the
heating element is installed, the heating element 16 of Figs. 10 and 11 will
be mounted within
the tank 11 such that the greatest cross-sectional area 26 is level with
respect to the floor 25.
By matching the pattern of apertures 82 on the heating element flange 74 to
the pattern of
apertures 84 on the mounting flange 78 and the gasket 90, the operator ensures
that the
heating element 16 will be mounted with the desired orientation within the
tank 11.
[0046] Fig. 12 illustrates yet another alternate construction of a mounting
device 100.
Like reference numerals will be given to like parts where appropriate.
[0047] As illustrated in Fig. 12, the heating element 16 includes a non-
threaded heating
element flange 104 that mates with a non-threaded mounting flange 108 of the
mounting
device 100. The heating element flange 104 and the mounting flange 108 are
generally
cylindrical in shape. The heating element flange 104 is slightly smaller in
diameter than the
mounting flange 108 such that the heating element flange 104 fits within the
mounting flange
108 to couple the heating element 16 to the tank 11. It is understood that in
other
embodiments, the mounting flange might have a smaller diameter such that the
mounting
flange fits within the heating element flange.
[0048] The mounting flange 108 and the heating element flange 104 are designed
such
that the flanges will only cooperate with each other in a predetermined
position to ensure that
the heating element 16 is coupled to the tank 11 in the desired orientation
(i.e., the heating
element 16 is level with respect to the floor 25). In the illustrated
construction, the mounting
flange 108 includes a protrusion 112 and the heating element flange includes a
channel 116
that receives the protrusion 112 when the heating element 16 is coupled to the
mounting
device 100. Aligning the protrusion 112 and the channel 116 to couple the
heating element
16 to the tank 11 ensures the desired final orientation of the heating
element. It is understood
that in other constructions, the protrusion could be located on the heating
element flange and
the channel located on the mounting flange. It is also understood that other
types of mating
mechanisms could be used on the heating element flange and mounting flange to
ensure the
desired orientation. For example, the protrusion can be a bump that cooperates
with a,
channel, a notch, or other aperture, the protrusion could be a rod, nail,
screw, weldment, or
bolt that is received by a notch, channel, or other aperture, or the mating
mechanism could be
a ball and spring detent mechanism as is well known in the art. In other
constructions,
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multiple protrusions of various geometrical configurations could be used that
fit within an
aperture of mating geometric configuration. These and other mating mechanisms
that ensure
that the heating element is mounted within the tank in a desired configuration
are possible
and would fall within the scope of the present invention.
[0049] A cylindrical gasket 120 is coupled to the heating element flange 104
such that
when the heating element 16 is coupled to the mounting device 100, the gasket
120 fits
between the heating element flange 104 and the mounting flange 108. The gasket
120
includes a channel 124 that aligns with the channel 116 on the heating element
flange 104
such that when coupled between the flanges, the channel 124 also receives the
protrusion
112. A compression element, such as a clamp 128, is coupled to the outside of
the mounting
flange 108. The clamp 128 of the illustrated construction is a hose clamp, but
it is understood
that in other constructions, other types of clamps, including other mechanical
clamps, and
other types of compression elements can be used. When the heating element
flange 104 and
gasket 120 are coupled within the mounting flange 108, the clamp 128 is
tightened by turning
screw 132 to coinpress the gasket 120 between the flanges 104, 108, providing
a water-tight
seal between the heating element 16 and the tank 11.
[0050] The mounting devices discussed above can also be utilized to perform a
method of
installing a heating element in a water heater. The mounting device is coupled
to a wall of
the water tank 11, such as by welding, gluing, soldering, conventional
fastening, or other
known mechanical coupling methods. The heating element flange is then mated
with the
mounting flange, coupling the heating element 16 to the mounting device to
ensure that the
greatest cross-sectional area 26 is level with respect to the floor 25.
Coupling the heating
element flange to the mounting flange compresses the flanges to form a water-
tight seal
between them.
[0051] In the construction illustrated in Figs. 1 and 4, coupling the flanges
includes
threading the heating-element flange 28 into the mounting flange 30. Threading
the flanges
together also function to compress the 0-ring 44 between the flanges,
providing a water-tight
seal between the flanges. To assist a person installing the heating element 16
in obtaining the
desired level orientation of the heating element 16 within the tank 11, the
method can also
include aligning the identification mark (the arrow 64 in the illustrated
embodiment) in the
predetermined position to ensure the level orientation. It is understood that
while in the
illustrated construction the heating element 16 is manually installed, in
other constructions
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the heating element can be automatically installed by a robot or other
machinery. In such
constructions, the identification mark would be aligned by the machine to
ensure the desired
orientation.
[0052] In the construction of Figs. 10 and 11, coupling the flanges includes
aligning the
apertures 82, 84, and 94 of the heating element flange 74, the mounting flange
78, and the
gasket 90 such that the gasket 90 fits between the heating element flange 74
and mounting
flange 78. The fasteners 86 are then inserted through the apertures and are
tightened to
couple the heating element 16 to the tank 11. The tightening of the fasteners
86 compresses
the gasket 90 between the flanges, providing a water-tiglit seal between the
heating element
16 and the tank 11.
[0053] In the construction of Fig. 12, coupling the flanges includes placing
the clamp 128
around the outside of the mounting flange 108, and placing the gasket 120 on
the heating
element flange 104 such that the channels 116, 124 are aligned. The channel
116 of the
heating element flange 104 is then mated with the protrusion 112 of the
mounting flange 108
and the heating element flange 104 is inserted into the mounting flange 108
with the gasket
120 therebetween. The clamp 128 is tightened down over the mated flanges,
compressing the
gasket 120 therebetween to form a water-tight seal between the heating element
16 and the
tank 11.
[0054] The above-described methods and apparatus have been illustrated and
described
for use in a storage-type, electric water heater. However, it is understood
that in other
constructions, the methods and apparatus illustrated in Figs. 1-12 could also
be used in other
types of fluid heating apparatus and still fall within the scope of the
present invention. For
example, the mounting device and method of mounting could be used in a
commercial or
industrial coffee maker, or any other fluid heating apparatus having a tank
that holds fluid to
be heated, and where the heating element is coupled to the tank such that the
heating element
is exposed to the fluid within the tank. Utilizing the mounting device and
method of
mounting in any similar fluid heating apparatus would assist in the
installation of the heating
element in the tank to ensure the desired level orientation of the heating
element within the
fluid tank.
[0055] Various other features and advantages of the invention are set forth in
the
following claims.
