U.S. patent application number 15/544448 was filed with the patent office on 2018-09-20 for fire tube heater.
The applicant listed for this patent is Camus Hydronics Ltd.. Invention is credited to Daniel Chai, Claudio Petracca, Domenic Ruscio.
Application Number | 20180266726 15/544448 |
Document ID | / |
Family ID | 56416481 |
Filed Date | 2018-09-20 |
United States Patent
Application |
20180266726 |
Kind Code |
A1 |
Chai; Daniel ; et
al. |
September 20, 2018 |
Fire Tube Heater
Abstract
A fire tube heater assembly, sometimes referred to as boilers
and/or water heaters, and method of accommodating elongation of the
fire tubes associated with such heating devices. The fire tube
heater assembly includes a plurality of fire tubes that are
configured and oriented to effectuate efficient thermal exchange
between the heating fluid, commonly a gas combustion product, and
the fluid being heated. At least one end of the plurality of tubes
are supported by a tube support. The tube support includes a
bellows or other deformable structure that accommodates changes in
the longitudinal length associated with thermal expansion and
contraction of the fire tubes during operation of the first tube
heater assembly and in a manner that maintains segregation between
the heating and heated fluid flows.
Inventors: |
Chai; Daniel; (Ontario,
CA) ; Petracca; Claudio; (Ontario, CA) ;
Ruscio; Domenic; (Ontario, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Camus Hydronics Ltd. |
Ontario |
|
CA |
|
|
Family ID: |
56416481 |
Appl. No.: |
15/544448 |
Filed: |
January 25, 2016 |
PCT Filed: |
January 25, 2016 |
PCT NO: |
PCT/IB2016/000082 |
371 Date: |
July 18, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62107062 |
Jan 23, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01K 5/00 20130101; F24H
9/1836 20130101; F24H 1/205 20130101 |
International
Class: |
F24H 1/20 20060101
F24H001/20; F24H 9/18 20060101 F24H009/18 |
Claims
1. A fire tube heater assembly comprising: a housing; a plurality
of tubes disposed in the housing; and a tube support constructed to
support at least two of the plurality of tubes and maintain a
segregation between a combustion gas flow and a fluid disposed in
the housing and effectuate thermal exchange therebetween, the tube
support including a bellows section constructed to accommodate
changes in the length of the at least two of the plurality of tubes
caused by thermal response to operation of the fire tube
heater.
2. The fire tube heater assembly of claim 1 wherein the plurality
of tubes is further defined as a first group of tubes and a second
group of tubes that are both supported by the tube support.
3. The fire tube heater assembly of claim 2 wherein the bellows
section is disposed between the first group of tubes and the second
group of tubes.
4. The fire tube heater assembly of claim 1 wherein the plurality
of tubes are oriented in a concentric circular pattern.
5. The fire tube heater assembly of claim 1 wherein each of the
plurality of tubes has an elongated cross-sectional shape.
6. The fire tube heater assembly of claim 1 further comprising a
first inlet and a first outlet through the housing that are fluidly
connected to a chamber configured to contain the fluid and a second
inlet and a second outlet through the housing associated and
fluidly connected to the plurality of tubes.
7. The fire tube heater assembly of claim 1 wherein the bellows
section is nearer a bottom of the housing than a top of the
housing.
8. The fire tube heater assembly of claim 7 further comprising a
baffle configured to direct the fluid toward the plurality of
tubes.
9. The fire tube heater assembly of claim 1 further comprising a
divider cylinder disposed about the plurality of tubes and
positionally fixed relative to the housing and configured to
segregate the fluid from the combustion gas flow.
10. The fire tube heater assembly of claim 1 further comprising a
burner configured to generate the combustion gas flow and fluidly
connected to the plurality of tubes.
11. A method of accommodating elongation of fire tube heater tubes
during operation of a fire tube heater, the method comprising:
supporting a plurality of fire tubes with a tube support structure
that is deformable to concurrently accommodate changes in a
longitudinal length of more than one of fire tubes.
12. The method of claim 11 wherein the tube support structure is
formed as a bellows section and a first end of the bellows section
is secured to a housing of fire tube heater and a second end of the
bellows section is secured to each of the plurality of fire tubes
and is movable relative to the first end.
13. The method of claim 12 wherein the second end of the bellows
section moves away from the first end in a direction aligned with a
longitudinal axis of the plurality of fire tubes as a temperature
of the fire tubes increases.
14. The method of claim 12 further comprising aligning the first
end and the second end of the bellows section when the fire tube
heater is near an unheated condition.
15. The method of claim 11 further comprising rigidly supporting a
longitudinal end of each of the plurality of fire tubes that is
opposite the tube support.
16. The method of claim 11 further comprising providing a baffle to
direct a flow of a fluid being heated in a radial direction toward
the plurality of fire tubes.
17. A boiler tube support assembly comprising: a body configured to
sealing cooperate with an end portion of a plurality of fire tubes;
and a bellows section that extends in an outward direction aligned
with a longitudinal axis of the plurality of fire tubes and which
is disposed between a first portion of the body that is
positionally secured relative to a housing disposed about the
plurality of fire tubes and a second portion of the body that is
movable relative to the first portion along the longitudinal axis
in response to changes in temperature of the plurality of fire
tubes.
18. The boiler tube support assembly of claim 17 wherein the first
portion of the body and the second portion of the body both extend
in a direction that is transverse to the longitudinal axis
associated with the plurality of fire tubes.
19. The boiler tube support assembly of claim 17 wherein the
bellows section is constructed to maintain separation between a
heating fluid flow and a heated fluid flow.
20. The boiler tube support assembly of claim 19 further comprising
at least one baffle disposed in the housing and oriented to direct
the heated fluid flow in a radial direction toward the plurality of
fire tubes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/107,062 filed on Jan. 23, 2015 titled "Fire Tube
Heater" and the disclosure of which is expressly incorporated
herein.
FIELD OF THE INVENTION
[0002] The present invention relates generally to fluid heating
devices, sometimes commonly referred to as boilers or water
heaters, and more particularly, to a fire tube heater assembly that
maintains separation or segregation between hot combustion gas
flows and the heated fluid flow while accommodating changes in the
longitudinal length of the fire tubes during operation of the fire
tube heater assembly associated with the thermal contraction and
expansion of the fire tubes during operation the heater
assembly.
BACKGROUND OF THE INVENTION
[0003] Fire tube heater assemblies such as boilers and/or water
heaters are commonly used for transferring heat from a hot fluid,
such as a combustion gas or heating fluid, to a relatively cooler
fluid or a heated fluid, such as water. Traditional heat
exchangers, particularly fire tube heat exchangers, utilized a tube
bundle made up of a plurality of tubes that each extend between a
respective tube inlet end and respective tube outlet end. During
operation of the heating device, the physical shape of these tubes
changes in response to the thermal properties of the material that
form the respective tubes as well as the operating parameters
associated with utilization of the heating assembly. Generating the
desired thermal exchange commonly requires a plurality of tubes and
a spacing of the tubes that supports efficient thermal exchange
associated with the flame or combustion gases and the surrounding
fluid, such as water, that is to be heated.
[0004] The generally elongate shape of the plurality of tubes and
the thermal exchange associated therewith, requires consideration
as to the mounting of the alternate ends of the tubes and/or the
construction of the tubes to accommodate elongation of the tubes in
a manner that maintains a sealed interaction between the passages
associated with the heating fluid flow, such as the combustion
process, and the passages associated with the passage of the heated
fluid flow through the assembly. Understandably, the combustion gas
fluid flow and the heated fluid flow must remain isolated from one
another throughout the heat exchange process. Significant
temperature differences can exist between those parts of the heat
exchanger which are in contact with the heating fluid and those
parts which are in contact with cooler gases associated with the
heating process and/or liquid associated with the heated fluid. It
is further appreciated that significant temperature changes can
occur throughout the heating process and or the respective or
desired heating conditions and/or demands associated with use or
operation of the fire tube heater assembly. These temperature
differentials can result in thermal expansion and/or contraction of
the fire tube heater tubes as well as temperature gradients between
respective portions of the heating assembly and associated with the
discrete portions of the heating and heated fluid flows associated
therewith. These temperature differentials and gradients cause
stresses in the joints between the various components and in the
components themselves. If unaddressed or accommodated, these
stresses can detract from efficient operation of the fire tube
heater assembly and/or premature failure of the desired fluid
operability of the fire tube heater assembly.
[0005] Fire tube heater assemblies generally include a housing that
encloses a heated fluid path and a plurality of fire tubes which
are contained within or otherwise pass through the housing. The
fire tubes are supported and distributed in the volume of the
housing to achieve an efficient thermal exchange between the
heating fluid or combustion gas flow and the heated fluid material
or flow that generally surrounds the plurality of fire tubes. The
fire tubes are arranged in the housing to effectuate an efficient
thermal exchange between the respective fluids and are supported in
a manner that maintains fluid isolation between the respected
heating and heated fluid flows. The fire tubes are commonly much
hotter than the surrounding shell or housing of the fire tube
heater assembly and can be subjected to various different operating
temperatures as well as temperature deviations and rates of
temperature change during operation of the fire tube assembly. That
is, the various demands associated with operation of the fire tube
heater assembly affect the relative temperature of the plurality of
fire tubes. The relative temperature of so the fire tubes affects
the longitudinal length of the discrete fire tubes. Said in another
way, a longitudinal length of the fire tubes commonly changes
during operation of the fire tube heater assembly due to thermal
expansion and contraction of the fire tubes during operation of the
fire tube heater assembly. Alternatively, if the fire tubes are so
rigidly supported relative to the underlying fire tube heater
assembly, the alternate ends of the discrete fire tubes can be
subjected to undesirable stresses due to the heating and cooling
cycles associated with operation of the fire tube heater
assembly.
[0006] Recognizing such concerns, others have provided fire tube
heater assemblies and/or heater exchanger arrangements wherein a
plurality of tubes are constructed to accommodate changes to
longitudinal lengths of the discrete tubes in response to the
operating state of the underlying heating device. Such
configurations commonly provide a slidable header arrangement, such
as arrangements similar to those disclosed in U.S. Pat. No.
7,220,392 and U.S. Patent Application Publication No. 2014/0000845,
wherein one end of a plurality of heating tubes are rigidly secured
to a header arrangement and another end of the plurality of tubes
are supported by a header arrangement that slideably cooperates
with the underlying housing associated with the heater or heat
exchanger assembly. Still others, such as U.S. Pat. No. 8,844,471,
provided arrangements that include deformable tube assemblies that
accommodate the longitudinal thermal expansion and contraction of
the discrete tubes by accommodating lateral deflection of the
discrete tubes during elongation and/or contraction of the discrete
tubes. Each approach includes respective drawbacks.
[0007] First, providing a slidable but sealed connection between a
header that supports a plurality of tubes and an underlying housing
associated with the heater assembly complicates the construction of
the housing and heater assembly and increases the potential for
fluid failure of heating arrangement. That is, the repeated
oscillation of the header relative to the housing increases the
potential for the development of system leakage associated with the
movable sealed interaction between the header assembly and the
housing. Although the laterally deformable tube assemblies negate
this consideration, such arrangements complicate manufacture of the
discrete tubes and complicate the considerations associated with
tube layout so as to accommodate the various lateral deflections
associated with the plurality of tubes. Further, such arrangements
are susceptible to detracted thermal efficiencies and greater
thermal gradients associated with the thermal exchange between the
discrete fluids due to the various positions of the tubes relative
to one another and the surrounding fluid during the thermal
expansion and contraction of the discrete tubes. That is, during
different operating conditions and/or temperatures, portions of
discrete tubes may achieve different relative orientations such
that non-uniform spacing occurs between the discrete portions of
discrete tubes thereby affecting the fluid exchange associated with
the surrounding heated fluid. Further, such approaches can result
in undesirable concentrations and directions associated with tube
stresses during elongation and contraction of the discrete
tubes.
[0008] Accordingly, there is a need for a fire tube heater assembly
that accommodates thermal expansion and contraction of the
plurality of fire tubes in a manner that maintains segregation
between the discrete fluid flows and does not undesirably affect
the thermal efficiently or create) undesirable thermal gradients
associated with operation of the of result fire tube heater
assembly.
SUMMARY OF THE INVENTION
[0009] The present invention discloses a fire tube heater assembly
that overcomes one or more of the drawbacks discussed above. A fire
tube heater assembly, sometimes referred to as boilers and/or water
heaters, and method of accommodating elongation of the fire tubes
associated with such heating devices are disclosed. The fire tube
heater assembly includes a plurality of fire tubes that are
configured and oriented to effectuate efficient thermal exchange
between the heating fluid, commonly a gas combustion product, and
the fluid being heated. At least one end of the plurality of tubes
are supported by a tube support. The tube support includes a
bellows or other deformable structure that accommodates changes in
the longitudinal length associated with thermal expansion and
contraction of the fire tubes during operation of the first tube
heater assembly and in a manner that maintains segregation between
the heating and heated fluid flows.
[0010] Another aspect of the invention that includes one or more
features or aspects that are usable or combinable with the above
aspect discloses a fire tube heater assembly having a housing and a
plurality of tubes disposed in the housing. The assembly includes a
tube support that is constructed to support at least two of the
plurality of tubes and maintain a segregation between a combustion
gas flow and a fluid disposed in the housing and effectuate thermal
exchange therebetween. The tube support includes a bellows section
that is constructed to accommodate changes in the length of the at
least two of the plurality of tubes caused by thermal response to
operation of the fire tube heater.
[0011] A further aspect of the invention that includes one or more
features or aspects that are combinable with the features and
aspects above discloses a method of accommodating elongation of
fire tube heater tubes during operation of a fire tube heater. The
method includes supporting a plurality of fire tubes with a tube
support structure that is deformable to concurrently accommodate
changes in a longitudinal length of more than one of fire tubes
during operation of the fire tube assembly.
[0012] Another aspect of the invention that includes one or more
features or aspects that are combinable with the features and
aspects above discloses a boiler tube support assembly. The boiler
tube support assembly includes a body that is configured to sealing
cooperate with an end portion of a plurality of fire tubes. A
bellows section extends in an outward direction that is aligned
with a longitudinal axis of the plurality of fire tubes and is
disposed between a first portion of the body and a second portion
of the body. The first portion of the body is positionally secured
relative to a housing disposed about the plurality of fire tubes
and the second portion of the body is movable relative to the first
portion of the body along the longitudinal axis in response to
changes in temperature of the plurality of fire tubes.
[0013] These and other aspects, features, and advantages of the
present invention will be made apparent for the following detailed
description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The drawings illustrate preferred embodiments presently
contemplated for carrying out the invention. In the drawings:
[0015] FIG. 1 is an elevational cross section view of a fire tube
heater assembly or apparatus according to the present
invention;
[0016] FIG. 2 is a top plan view a fire tube mounting structure of
the fire tube heater assembly shown in FIG. 1;
[0017] FIG. 3 is an elevational cross section view of the fire tube
mounting structure shown in FIG. 2;
[0018] FIG. 4 is a perspective view of the view shown in FIG.
3;
[0019] FIG. 5 is an elevational cross section view of a portion of
the fire tube heater assembly shown in FIG. 1 proximate the fire
tube mounting structure shown in FIGS. 2-4; and
[0020] FIG. 6 is a graph that shows efficiencies associated with
operation of the fire tube heater assembly shown in FIG. 1 as a
function of the temperature of the heated fluid inlet flow.
DETAILED DESCRIPTION
[0021] FIG. 1 shows a cross-sectional view of a water heater, water
heating apparatus, boiler, or fire tube heater assembly 10
according to the present invention. Fire tube heater assembly 10
includes a housing 12 that generally defines a vertically oriented
footprint of the device. A burner 14 is associated with a
combustion chamber 16 which is configured to generate a combustion
gas flow 18 associated with generating the thermal exchange
associated with operation of fire tube heater assembly 10. It
should be appreciated that the operation of burner 14 can be
configured and/or otherwise manipulated to satisfy various demands
associated with the desired volumes, throughputs, and parameters
associated with the intended demand associated with use of fire
tube heater assembly 10.
[0022] Fire tube heater assembly 10 includes a plurality of fire
tubes or simply tubes 20, 22 that extend in a longitudinal
direction, indicated by arrow 24, within the confines of housing
12. Fire tube heater assembly 10 includes a first or top tube sheet
or upper tube support 28 and a second or bottom or lower tube
support 30. Understandably, the terms top, bottom, upper, and lower
are indicative of heater assemblies having generally vertical
operating orientations but it is appreciated that the present
invention is applicable to other heater configurations and that the
functions associated with the same could be provided in alternate
orientations.
[0023] Tube supports 28, 30 are disposed at generally opposite
longitudinal ends of tubes 20 and/or tubes 22 and are constructed
to provide a desired orientation of the plurality of tubes 20, 22
relative to the generally surrounding housing 12. A heated fluid
cavity 34 is formed to generally encircle the surface areas
associated with tubes 20, 22 to effectuate an efficient thermal
exchange between tubes 20, 22 and the fluid, such as water, that
surrounds them.
[0024] Although described hereafter as water and/or combustion gas
fluid passages and/or portions thereof, it is appreciated that fire
tube heater assembly 10 can be utilized to effectuate thermal
exchanges between various fluid flows wherein it is desired to
maintain fluid isolation between the respective fluid flows
regardless of the composition or constituencies of the discrete
fluid flows. For brevity, the fluid flow passage associated the
combustion gas fluid path is hereafter referred to as heating fluid
flow path and features whereas the fluid paths associated with the
alternate fluid, whether provided as water or another fluid, are
referred to as features of the heated fluid flow path and/or
features. It should be appreciated that such monikers or
nomenclature are utilized to designate the discrete features of
fire tube heater assembly 10 associated with the direction of the
thermal exchange between the respective fluid flows during
operation of the fire tube heater assembly during demand or "ON"
conditions. When utilized as a water heating appliance, fire tube
heater assembly 10 includes a heated fluid inlet or water inlet 36
and a heated fluid outlet or water outlet 38 associated with the
flow of the heated fluid through fire tube heater assembly 10. As
should be appreciated, during a demand condition, the temperature
associated with the fluid flow at heated fluid inlet 36 is less
than the temperature associated with the fluid flow at heated fluid
outlet 38 due to the thermal exchange associated with the thermal
interaction of the water fluid flow being directed over and about
tubes 20, 22 associated with the combustion gas flows.
[0025] During operation, heated combustion gases travel through
tubes 20 in a generally downward direction, indicated by arrows 40,
pass through lower tube support 30, are directed toward the
plurality of radially outward oriented tubes 22, and exit fire tube
heater assembly 10 at a vent pipe 46. Such a flow methodology is
only one exemplary flow methodology associated with the present
invention. Any condensate generated on the heating fluid side of
fire tube heater assembly 10 during the thermal exchange with the
heated fluid can be removed from the system via a condensate trap
and/or drain 47 disposed in a lower portion of fire tube heater
assembly 10.
[0026] During operation, such as during start up, shut down, and
deviations associated with the load or demand upon fire tube heater
assembly 10, the longitudinal length of one or more of tubes 20, 22
changes in response to the thermal exchange between the combustion
gases associated with the internal volume defined by tubes 20, 22
and the flow of the heated fluid around the tubes 20, 22. That is,
as the thermal output of the combustion process increases and/or
decreases, the temperature of the input water increases and/or
decreases, and/or the demand increases and/or decreases, the
longitudinal lengths of tubes 20, 22 increases and decreases due to
the thermal properties of tubes 20, 22 and in response to the
deviations in the thermal operations of fire tube heater assembly
10.
[0027] Referring to FIGS. 1-5, lower tube support 30 is defined by
a body 100 that includes a first portion 102 and a second portion
104 that are movable relative to one another in a generally axial
direction aligned with a longitudinal axis 24 of one or more of
tubes 20, 22. An outer wall 106 of body 100 extends from first
portion 102 of lower tube support 30 so as to define a cavity 110
therebehind. First and second portions 102, 104 of lower tube
support plate 30 are supported by a bellows structure, bellows
assembly, or simply a bellows 120 that accommodates deviations in
the longitudinal length of one or more of tubes 20, 22 in response
to changes in the longitudinal length of tubes 20, 22 as a function
of the thermal performance of fire tube heater assembly 10.
[0028] Although bellows 120 is disclosed below as accommodating
changes to the longitudinal length of tubes 20, associated with the
primary heat exchange with the heated fluid, it is appreciated that
fire tube heater assembly 10 could be configured so that all of
tubes 20, 22 were associated with the movable portion of lower tube
support 30.
[0029] Bellows 120 is defined by a first portion 122 that extends
in a generally downward and circumferential direction from first
portion 102 of lower tube support 30. A second portion 124 of
bellows 120 extends from a free or cantilevered end of first
portion 122 of bellows 120 in a circumferential and longitudinal
direction toward second portion 104 of lower tube support 30. An
upper circumferential edge associated with second portion 124 of
bellows 120 is sealingly secured to second portion 104 of lower
tube support 30. Second portion 124 of bellows 120 has a generally
serpentine cross-sectional shape whereas first portion 122 of
bellows 120 has a generally planar tubular shape. The generally
serpentine cross-sectional shape of first portion 122 of bellows
120 accommodates translation of second portion 104 of lower tube
support 30 in a direction aligned with the longitudinal axis 24 of
tubes 20, 22 relative to first portion 102 of lower tube support 30
during thermal expansion and contraction of tubes 20 during
operation of fire tube heater assembly 10.
[0030] Said in another way and referring to FIGS. 3 and 4,
longitudinally directed forces directed upon second portion 104 of
lower tube support 30 associated with the thermal expansion and
contraction of tubes 20 effectuates compression of second portion
124 of bellows 120 thereby translating second portion 124 of
bellows 120 in a generally upward or downward axial direction
relative to first portion 122 of bellows 120. Although first and
second portions 102, 104 of lower tube support 20 are show as being
generally contained in a common plane that is oriented generally
transverse to the longitudinal direction associated with axis 24,
it is appreciated that other relative orientations of first portion
102 and second portion 104 of lower tube support 30 are envisioned.
It should be appreciated that the elongation or contraction, or
changes to the axial length of tubes 20 during operation of fire
tube heater assembly 10 is structurally accommodated by the
movement a second portion 104 of lower tube support 30 relative to
the first portion 102 of lower tube support 30 and the
compression/expansion associated with second portion 124 of bellows
120. It is further appreciated that the generally transverse
orientations associated with the interaction of tubes 20, 22 with
the respective first and second portions 102, 104 of lower tube
support 30 provide a robust sealed interaction between the
plurality of tubes 20, 22 and lower tube support 30 in a manner
that maintains the relative fluid isolation or segregation
associated with the fluid flows such as the combustion gas flows
associated with the internal volumes of tubes 20, 22 and the
working fluid or heated fluid flows that generally surround the
elongated surfaces of tubes 20, 22 within housing 12.
[0031] Lower tube support 30 includes a generally circumferential
groove 130 that is formed between first portion 102 and second
portion 104 of lower tube support 30 such that a volume 132 formed
between first portion 122 and second portion 124 of bellows 120 can
be occupied the heated fluid flow during operation of fire tube
heater assembly 10 thereby maintaining a desired operating pressure
associated with a pressurized side of fire tube heater assembly 10.
A volume 140 that generally underlies second portion 104 of lower
tube support 30 accommodates the passage of the combustion gases or
heating fluid flow associated with the internal passages of tubes
20, supported by second portion 104 of lower tube support 30,
between tubes 20, around baffle 120, and toward the radially
outward oriented tubes 22.
[0032] Referring to FIGS. 2 and 4, each of a plurality of elongated
slots 150, 152 associated with a respective one of first portion
102 and second portion 104 of lower tube support 30 are constructed
to accommodate a secure sealed mechanical cooperation of a
respective corresponding tube 20, 22 associated with fire tube
heater assembly 10. Preferably, each of tubes 20, 22 is welded to a
respective one of the first portion 102 and second portion 104 of
lower tube support 30 such that the passages associated with each
respective tube 20, 22 is fluidly connected to the volume
associated with the opposing lateral side of lower tube support 30
via the respective opening or slot 150, 152 associated with lower
tube support 30. It is appreciated that although tubes 20 have a
generally elongate cross section shape and are oriented in a
generally radially uniform pattern relative to a longitudinal axis
of fire tube heater 10 and tubes 22 are oriented in a radially
staggered pattern and such that the longitudinal cross section of
each tube 22 is oriented as a crossing direction relative to the
longitudinal axis associated with the cross section of the nearest
radially inward tube 20 as indicated by slots 150 (FIG. 2) is only
one exemplary arrangement of the orientation of tubes 20, 22.
[0033] Regardless of the discrete orientations of tubes 20 relative
to tubes 22, and vice versa, it should be appreciated from FIG. 1
that the temperature associated with the heating fluid flow will
decrease as it passes in a downward relative direction associated
with tubes 20 and an upward relative direction associated with
tubes 22 as the thermal energy associated therewith transfers to
the working or heated fluid. It should further be appreciated that
the temperature of the heated fluid will increase as the working or
heated fluid passes in a radially inward direction and/or opposing
longitudinal directions associated with the plurality of tubes 20,
22 and experiences a thermal exchange with the outer surfaces of
the respective tubes 20, 22 and interacts with the respective
baffles 120, 121 associated with directing the flow of working or
heated fluid thereacross and through fire tube heater assembly
10.
[0034] The movable association of second portion 104 of lower tube
support 30 relative to first portion 102 of lower tube support 30
accommodates changes to the longitudinal length of tubes 20 secured
thereto in response to deviations associated with the operating
load caused by the thermal expansion of the respective tubes 20
and/or 22. As should be appreciated, second portion 104 of lower
tube plate 30 accommodates the elongation of a plurality of tubes
20 associated with operation of fire tube heater assembly 10. That
is, rather than providing discrete tubes that are each individually
tailored and constructed to accommodate the thermal elongation
and/or contraction associated therewith, or providing a slidable
association between discrete separate portions of housing 12,
deformable lower tube support 30 facilitates a robust and secure
tube mounting structure such that body 100 associated with lower
tube support 30 accommodates deviations in the longitudinal length
associated with the plurality of the respective tubes 20, 22 of
fire tube heater assembly 10 caused by changes in the thermal
loading associated therewith while maintaining of the desired fluid
isolation between the combustion gas or heating fluid side or
passages and the water or heated fluid side or passages associated
with operation of fire tube heater assembly 10.
[0035] Referring to FIG. 6, the efficiency associated with the
operation of fire tube heater assembly 10 can be affected by the
heated fluid inlet flow rate and temperature. Efficiencies of
approximately 96.5% to approximately 99.3% can be achieved during
various heated fluid flow rater at heated fluid inlets flow
temperatures of approximately 4.4 degrees Celsius (approximately 40
degrees Fahrenheit). The efficiency of operation of fire tube
heater assembly 10 as well as the difference between the
efficiencies associated with a minimum inlet heated fluid flow
(indicated by trend A) and a maximum inlet heated fluid flow
(indicated by trend B) gradually decreases as the inlet heated
fluid flow temperature increases. As shown in FIG. 6, the
efficiency associated with operation of fire tube heater assembly
10 can range from approximately 88.6% to 99.5% as the inlet heated
fluid flow temperature ranges between the a lower input heated flow
and higher input heated fluid flow and from temperatures of
approximated 4.4 degrees Celsius to approximately 76.7 degrees
Celsius (approximately 170 degrees Fahrenheit) and thereby provides
an improved operating efficiency throughout the range of operation
of similar fire tube heater assemblies. Fire tube heater assembly
10 is constructed to accommodate a range of on-demand throughputs
from approximately 100% of the heated fluid throughputs to
approximately 4% of the heated fluid throughout with a negligible
deviation to the efficiency associated with fire tube heater
assembly 10. Said in another way, the efficiency associated with
operation of fire tube heater assembly 10 is maintained across the
firing or on-demand operation of the assembly 10.
[0036] Those skilled in the art will appreciate that other
advantages and features can be realized from the operating
parameters associated with fire tube heater assembly 10 which are
only exemplary of specific implementations of the present
invention. While certain embodiments of the invention have been
illustrated and described for purposes of the present disclosure,
changes in the arrangement and construction of parts may be made by
those skilled in the art and such changes are encompassed within
the scope and spirit of the present invention as defined by the
appended claims. The present invention has been described in terms
of the preferred embodiment, the embodiment disclosed herein is
directed to the assembly as generally shown in the drawings. It is
recognized that equivalents, alternatives, and modifications, aside
from those expressly stated, to the embodiments summarized, or the
embodiment shown in the drawings, are possible and within the scope
of the appending claims. The appending claims cover all such
alternatives and equivalents.
* * * * *