U.S. patent application number 12/371121 was filed with the patent office on 2009-09-17 for detonative cleaning apparatus mounting system.
This patent application is currently assigned to SHOCKSystem, Inc.. Invention is credited to Raymond N. Henderson, Kirk R. Lupkes.
Application Number | 20090229068 12/371121 |
Document ID | / |
Family ID | 40957229 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090229068 |
Kind Code |
A1 |
Henderson; Raymond N. ; et
al. |
September 17, 2009 |
DETONATIVE CLEANING APPARATUS MOUNTING SYSTEM
Abstract
An apparatus for cleaning a surface within a vessel has an
elongate combustion conduit extending from an upstream end to a
downstream end. The downstream end is associated with an aperture
in the wall of the vessel and is positioned to direct a shockwave
toward the surface. At least one hanger supports the combustion
conduit at least one location along a length of the combustion
conduit. A penetration conduit is positioned between the wall
aperture and an associated portion of the combustion conduit. Means
couple the combustion conduit to the penetration conduit so as to
accommodate relative longitudinal movement and/or relative angular
movement.
Inventors: |
Henderson; Raymond N.;
(Renton, WA) ; Lupkes; Kirk R.; (Renton,
WA) |
Correspondence
Address: |
MCCORMICK, PAULDING & HUBER LLP
CITY PLACE II, 185 ASYLUM STREET
HARTFORD
CT
06103
US
|
Assignee: |
SHOCKSystem, Inc.
Glastonbury
CT
|
Family ID: |
40957229 |
Appl. No.: |
12/371121 |
Filed: |
February 13, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61028491 |
Feb 13, 2008 |
|
|
|
Current U.S.
Class: |
15/316.1 |
Current CPC
Class: |
B08B 7/02 20130101; F28G
7/005 20130101; B08B 9/08 20130101; F28G 7/00 20130101; B08B 7/0007
20130101 |
Class at
Publication: |
15/316.1 |
International
Class: |
F23J 3/02 20060101
F23J003/02 |
Claims
1. An apparatus for cleaning a surface within a vessel, the
apparatus comprising: an elongate combustion conduit extending from
an upstream end to a downstream end associated with an aperture in
a wall of the vessel and positioned to direct a shock wave toward
said surface; means for movably supporting the combustion conduit
at one or more locations along a length of the combustion conduit;
a penetration conduit between the wall aperture and an associated
portion of the combustion conduit; and means for coupling the
combustion conduit to the penetration conduit so as to accommodate
at least one of relative longitudinal movement and relative angular
movement.
2. The apparatus of claim 1 wherein: the means for coupling
accommodates both said relative longitudinal movement and said
relative angular movement.
3. The apparatus of claim 1 wherein: the means for coupling
accommodates said relative longitudinal movement via a slip fit;
and the means for coupling accommodates the relative angular
movement via flexing.
4. The apparatus of claim 1 wherein: the means for coupling permits
at least 0.1 m of said relative longitudinal movement and at least
1.degree. of said relative angular movement, said relative angular
movement being about a transverse horizontal axis.
5. The apparatus of claim 4 wherein: the means for coupling
provides no more than 1.0 m of said relative longitudinal movement
and no more than 5.degree. of said relative angular movement.
6. The apparatus of claim 1 wherein the means for coupling
comprises: a bellows having an upstream end and a downstream end; a
plate secured to the bellows upstream end and having an aperture
accommodating the combustion conduit in a slip fit; and an upstream
end flange of said penetration conduit secured to the bellows
downstream end.
7. The apparatus of claim 6 wherein: the plate is formed in exactly
two segments.
8. The apparatus of claim 6 wherein: the means for coupling further
comprises a fibrous layer surrounding the combustion conduit within
the bellows and the penetration conduit.
9. The apparatus of claim 1 further comprising: means for
restraining the combustion conduit against thrust movement.
10. The apparatus of claim 9 wherein the means for restraining
comprises: at least two struts coupling the combustion conduit to a
fixed building structure.
11. The apparatus of claim 10 wherein: each of the struts comprises
a damper.
12. The apparatus of claim 11 wherein: the dampers are hydraulic
dampers.
13. The apparatus of claim 11 wherein: the dampers are resilient
non-hydraulic dampers.
14. The apparatus of claim 1 wherein: the means for movably
supporting comprises one or more spring hangers.
15. The apparatus of claim 1 wherein: the combustion conduit
comprises a plurality of segments assembled end-to-end.
16. An apparatus for cleaning a surface within a vessel, the
apparatus comprising: an elongate combustion conduit extending from
an upstream end to a downstream end associated with an aperture in
a wall of the vessel and positioned to direct a shock wave toward
said surface; one or more hangers supporting the combustion conduit
at one or more locations along a length of the combustion conduit;
a penetration conduit between the wall aperture and an adjacent
portion of the combustion conduit; and an expansion joint coupling
the combustion conduit to the penetration conduit so as to
accommodate relative angular movement.
17. The apparatus of claim 16 wherein: the expansion joint is an
elastomeric expansion joint.
18. The apparatus of claim 16 wherein: the expansion joint is a
metallic expansion joint.
19. The apparatus of claim 17 wherein: the expansion joint has a
downstream flange secured to an upstream flange of the penetration
conduit; the expansion device has an upstream flange secured to an
apertured plate accommodating the combustion conduit in a slip fit
having smaller clearance than a clearance between the combustion
conduit and the penetration conduit.
20. The apparatus of claim 16 further comprising: means for
transferring a recoil force to building structure bypassing the
vessel wall.
21. The apparatus of claim 20 wherein: the means comprise a
vertically sliding engagement with the building structure.
22. The apparatus of claim 20 wherein: the means comprise a
resilient damper.
23. The apparatus of claim 21 wherein: the means for transferring a
recoil force includes a plurality of elastomer bumpers.
24. An apparatus for cleaning a surface within a vessel, the
apparatus comprising: an elongate combustion conduit extending from
an upstream end to a downstream end associated with an aperture in
a wall of the vessel and positioned to direct a shock wave toward
said surface; one or more hangers supporting the combustion conduit
at one or more locations along a length of the combustion conduit;
a penetration conduit between the wall aperture and an adjacent
portion of the combustion conduit; an expansion joint coupling the
combustion conduit to the penetration conduit so as to accommodate
relative angular movement; and a damping unit for restraining the
combustion conduit against thrust movement including a plurality of
elastomer bumpers arranged on a rod, the rod engaging at least two
struts coupling the combustion conduit to a fixed building
structure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from and incorporates in
its entirety by reference U.S. Provisional Patent Application Ser.
No. 61/028,491, filed Feb. 13, 2008, entitled "Detonative Cleaning
Apparatus Mounting."
TECHNICAL FIELD OF THE INVENTION
[0002] The disclosure relates to industrial equipment. More
particularly, the disclosure relates to the detonative cleaning of
industrial equipment.
BACKGROUND OF THE INVENTION
[0003] Surface fouling is a major problem in industrial equipment.
Such equipment includes furnaces (coal, oil, waste, etc.), boilers,
gasifiers, reactors, heat exchangers, and the like. Typically, the
equipment involves a vessel containing internal heat transfer
surfaces that are subjected to fouling by accumulating particulate
such as soot, ash, minerals and other products and byproducts of
combustion, more integrated buildup such as slag and/or fouling,
and the like. Such particulate build-up may progressively interfere
with plant operation, reducing efficiency and throughput and
potentially causing damage. Cleaning of the equipment is therefore
highly desirable and is attended by a number of relevant
considerations. Often direct access to the fouled surfaces is
difficult. Additionally, to maintain revenue, it is desirable to
minimize industrial equipment downtime and related costs associated
with cleaning. A variety of technologies have been proposed. Such
systems are often identified as "soot blowers" after an exemplary
application for the technology.
[0004] Basic soot blower configuration is the scheme lance soot
blower. Additionally, combustion soot blower technologies have been
proposed. Recent examples include those of U.S. Pat. Nos. 7,011,047
and 7,442,034 and US Patent Publication Nos. 20050126594 and
20050130084, both now abandoned, the disclosures of which are
incorporated by reference in their entireties herein as if set
forth at length.
SUMMARY OF THE INVENTION
[0005] Accordingly, one aspect of the disclosure involves an
apparatus for cleaning a surface within a vessel. An elongate
combustion conduit extends from an upstream end to a downstream end
associated with an aperture in the wall of the vessel and
positioned to direct a shockwave toward the surface. One or more
hangers support the combustion conduit at one or more locations
along a length of the combustion conduit. A penetration conduit is
positioned between the wall aperture and an associated portion of
the combustion conduit. Means couple the combustion conduit to the
penetration conduit so as to accommodate one or both of relative
longitudinal movement and relative angular movement.
[0006] In various implementations, the means for coupling may
accommodate the relative longitudinal movement via a slip fit and
the relative angular movement via flexing. The slip fit may be of
an apertured plate held by a bellows or expansion joint. The
flexing may be of the bellows or expansion joint.
[0007] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a partially schematic side view of a soot blower
associated with an industrial furnace.
[0009] FIG. 2 is a top view of the soot blower of FIG. 1.
[0010] FIG. 3 is an enlarged side view of a discharge/outlet end of
the soot blower of FIG. 1.
[0011] FIG. 4 is a transverse sectional view of the soot blower of
FIG. 3.
[0012] FIG. 5 is a partial vertical longitudinal sectional view of
the soot blower end portion.
[0013] FIG. 6 is a view of a damper of the soot blower of FIG.
1.
[0014] FIG. 7 is a sectional view of the damper of FIG. 6.
[0015] FIG. 8 is a side view of an alternate soot blower.
[0016] FIG. 9 is a top view of the soot blower of FIG. 8.
[0017] FIG. 10 is a view of a first pair of thrust reaction plates
secured to a flange joint.
[0018] FIG. 11 is an end view of the plates and joint of FIG.
10.
[0019] FIG. 12 is an X-ray view of one of the plates of FIG.
10.
[0020] FIG. 13 is a view of the plate of FIG. 12.
[0021] FIG. 14 is an end view of the plates and joints carrying
devises.
[0022] FIG. 15 is an end view of plates and joints carrying first
alternatively oriented devises.
[0023] FIG. 16 is an end view of plates and joints carrying second
alternatively oriented devises.
[0024] FIG. 17 is a view of alternate thrust reaction plates
secured to a joint.
[0025] FIG. 18 is an end view of the plates and joint of FIG.
17.
[0026] FIG. 19 is a view of a single thrust reaction plate secured
between flanges of a joint.
[0027] FIG. 20 is an end view of the plate and joint of FIG.
19.
[0028] FIG. 21 is a top view of an alternate embodiment of the
sootblower of FIG. 1.
[0029] FIG. 22 is a side view of the sootblower of FIG. 21.
[0030] FIG. 23 is an end view of the thrust reaction plates and
joint of FIG. 22.
[0031] FIG. 24 is a perspective view of a thrust reaction plate of
FIG. 23.
[0032] Like reference numbers and designations in the various
drawings indicate like elements.
DETAILED DESCRIPTION
[0033] FIG. 1 shows a vessel (e.g., a boiler) 20 in a building 21.
One or more soot blower apparatus (soot blowers) 22 are positioned
to clean surfaces within the vessel interior 78. The exemplary
vessel comprises a wall 24. The exemplary wall 24 may include a
structural and/or insulative outer layer 26 and an inner layer 28.
In high temperature locations along the wall 24, the inner layer 28
may be a heat transfer layer formed of fluid (e.g., water)-carrying
tubes. Exemplary tubes are welded together to form a membrane wall.
In lower temperature locations, the inner layer 28 may be a steel
plate. For further structural reinforcement against internal or
external pressure loads, the wall 24 may include reinforcements
commonly known as buckstays 30. Exemplary buckstays 30 are steel
I-beams secured to each other and to the remaining wall structure
to form a rigid enclosure. The wall 24 is subject to thermal growth
as the vessel temperature increases. The growth may be accommodated
by suspending the vessel via the buckstays 30 from a relatively
fixed building structure such as a ceiling 32. As the vessel heats,
the wall 24 grows vertically downward.
[0034] Each soot blower 22 includes an elongate combustion conduit
36 extending from a first (e.g., an upstream/distal/inlet end) 38
away from the vessel wall 24 to a second (e.g.,
downstream/proximal/outlet) end 40 closely associated with the wall
24. Optionally, however, the end 40 may be well within the vessel
interior 78. In operation of each soot blower 22, combustion of a
fuel/oxidizer mixture within the conduit 36 is initiated proximate
the upstream end 38 (e.g., within an upstreammost 10% of a conduit
length) to produce a detonation wave which is expelled from the
downstream end 40 as a shock wave along with associated combustion
gases for cleaning surfaces within the interior volume of the
furnace. Each soot blower 22 may be associated with a fuel/oxidizer
source 42. Such source or one or more components thereof may be
shared amongst the various soot blowers. An exemplary source
includes a liquified or compressed gaseous fuel cylinder 44 and an
oxygen cylinder 46 in respective containment structures 48 and
50.
[0035] In one example, there is a single fuel (e.g., propane) and a
single oxidizer (e.g., the pure oxygen). In second example, the
oxidizer is a first oxidizer such as essentially pure oxygen. A
second oxidizer may be in the form of shop air delivered from a
central air source 52. In the second example, air may be stored in
an air accumulator 54. Fuel, expanded from that in the cylinder 46
may be stored in a fuel accumulator 56. Each exemplary source 42 is
coupled to the associated conduit 36 by appropriate plumbing.
Similarly, each soot blower 22 includes a spark box 60 coupled to
an igniter 61 for initiating combustion of the fuel oxidizer 4
mixture and which, along with the source 42, is controlled by a
control and monitoring system 62.
[0036] In exemplary embodiments of the second example, the fuels
are hydrocarbons. In particular exemplary embodiments, both fuels
are the same, drawn from a single fuel source but mixed with
distinct oxidizers: essentially pure oxygen for the predetonator
mixture; and air for the main mixture. Exemplary fuels useful in
such a situation are propane, MAPP gas, or mixtures thereof. Other
fuels are possible, including ethylene and liquid fuels (e.g.,
diesel, kerosene, and jet aviation fuels). The oxidizers can
include mixtures such as airloxygen mixtures of appropriate ratios
to achieve desired main and/or predetonator charge chemistries.
Further, monopropellant fuels having molecularly combined fuel and
oxidizer components may be options.
[0037] FIG. 1 shows further details of an exemplary soot blower 22.
The exemplary conduit 36 may be formed by a series of doubly
flanged conduit sections or segments arrayed from upstream to
downstream and a downstream nozzle conduit section or segment 72
having a downstream portion 74 extending through an aperture 76 in
the wall and ending in the downstream end or outlet 40 exposed to
the vessel interior 78. The term nozzle is used broadly and does
not require the presence of any aerodynamic contraction, expansion,
or combination thereof. Exemplary conduit segment material is
metallic (e.g., stainless steel). The outlet 40 may be located
further within the vessel if appropriate support and cooling are
provided. Within the vessel interior 78 are furnace interior tube
bundles 80, the exterior surfaces of which are subject to fouling
and which are to be cleaned by the soot blower 22.
[0038] A fuel/oxidizer charge may be introduced to the conduit
interior in a variety of ways. As noted above, there may be one or
more distinct fuel/oxidizer mixtures. Such mixture(s) may be
premixed external to the detonation conduit, or may be mixed at or
subsequent to introduction to the conduit. For example, there may
be distinct introduction of two distinct fuel/oxidizer
combinations: a predetonator combination; and a main combination.
There may also be a purge gas conduit connected to a purge gas
port. An end plate may be bolted to the upstream flange of the
upstream segment to seal the upstream end of the combustion conduit
and pass through the igniter/initiator 61 (e.g., a spark plug)
having an operative end in the conduit interior.
[0039] In operation, at the beginning of a use cycle, the
combustion conduit is initially empty except for the presence of
air (or other purge gas or flue gas). The fuel(s) and oxidizer(s)
are introduced.
[0040] With the charge(s) introduced, the spark box is triggered to
provide a spark discharge of the initiator igniting charge (or the
predetonator charge in a multi-charge example). The predetonator
charge (or single charge) may be selected for very fast combustion
chemistry, the initial deflagration quickly transitioning to a
detonation producing a detonation wave. Once such a detonation wave
occurs, it is effective to pass through the rest of the charge (or
the main charge which might, otherwise, have sufficiently slow
chemistry to not detonate within the conduit of its own accord).
The wave passes longitudinally downstream and emerges from the
downstream end 40 as a shock wave within the furnace interior,
impinging upon the surfaces to be cleaned and thermally and
mechanically shocking to typically at least loosen the
contamination. The wave will be followed by the expulsion of
pressurized combustion products from the detonation conduit, the
expelled products emerging as a jet from the downstream end 40 and
further completing the cleaning process (e.g., removing the
loosened material). After or overlapping such venting of combustion
products, a purge gas (e.g., air from the same source providing the
main oxidizer and/or nitrogen) is introduced through the purge port
to drive the final combustion products out and leave the detonation
conduit filled with purge gas ready to repeat the cycle (either
immediately or at a subsequent regular interval or at a subsequent
irregular interval (which may be manually or automatically
determined by the control and monitoring system). Optionally, a
baseline flow of the purge gas may be maintained between
charge/discharge cycles so as to prevent gas and particulate from
the furnace interior from infiltrating upstream and to assist in
cooling of the detonation conduit.
[0041] In various implementations, internal surface enhancements
may substantially increase internal surface area beyond that
provided by the nominally cylindrical and frustoconical segment
interior surfaces. The enhancement may be effective to assist in
the deflagration-to-detonation transition or in the maintenance of
the detonation wave.
[0042] The apparatus may be used in a wide variety of applications.
By way of example, just within a typical coal-fired furnace, the
apparatus may be applied to: the pendants or secondary
superheaters, the convective pass (primary superheaters and the
economizer bundles); air preheaters; selective catalyst removers
(SCR) scrubbers; the baghouse or electrostatic precipitator;
economizer hoppers; ash or other heat/accumulations whether on heat
transfer surfaces or elsewhere, and the like. Similar possibilities
exist within other applications including oil-fired furnaces, black
liquor recovery boilers, biomass boilers, waste reclamation burners
(trash burners), and the like.
[0043] To support the conduit 36, the exemplary soot blower 22
includes one or more hangers 100 and 102. The exemplary hanger 100
is positioned relatively upstream and the exemplary hanger 102
relatively downstream. The exemplary hanger 100 couples the conduit
36 to relatively fixed building structure, bypassing the vessel 20.
Exemplary relatively fixed building structure is as a transverse
horizontal I-beam 104 or the ceiling 32. The exemplary hanger 100
connects to a support point 106 along the conduit 36 such as a
hanger eyelet and to another eyelet 108 along the I-beam 104. The
exemplary hanger 100 is a spring hanger, more particularly constant
load spring hanger. Exemplary spring hangers are available from
LISEGA, Inc., Newport, Tenn.
[0044] The exemplary hanger 102 couples the conduit 36 to the
vessel 20. In the exemplary embodiment, the hanger 102 is coupled
to an eyelet 110 secured to one of the buckstays 30 above the
conduit 36. The exemplary hanger 102 connects to a collar 112
encircling the conduit in a slip fit (discussed further below). The
exemplary hanger 102 is a spring hanger (e.g., a simple spring
hanger, not a constant load spring hanger).
[0045] The soot blower 22 includes means for resisting recoil of
the conduit. The exemplary means for resisting recoil may couple
the conduit to relatively fixed building structure to transfer
recoil forces to the building structure (and not the wall 24).
FIGS. 1 and 2 show means as including a pair of struts 120 (e.g.,
respectively to the left and right of the conduit 36) coupling the
conduit to vertical posts 122. The exemplary struts 120 include an
elongate shaft 124 having upstream and downstream ends. At the
respective upstream and downstream ends, joints 126 and 128 are
provided respectively engaging mating coupling elements 130 and 132
on the conduit 36 and posts, respectively. The exemplary joints 126
and 128 are rods each having a threaded first end mated to end caps
of the shaft and having an eyelet second end carrying an apertured
ball. The exemplary couplings 130 and 132 are mating devises
carrying pins extending through the associated balls. As is
discussed further below, the exemplary upstream couplings 130 are
mounted to one or more plates 140, 142. Exemplary plates 140 and
142 are respectively mounted to the right and left sides of the
conduit 36. Exemplary plates 140 and 142 are mounted to a
downstream face of an upstream flange of one of the sections of the
conduit 36. The coupling elements 130 are, in turn, mounted to the
downstream faces of the plates 140 and 142.
[0046] Upon firing of the conduit, recoil forces tend to drive the
conduit away from the vessel 20. Slip fit between the collar 112
and the conduit may allow a certain amount of movement. However,
the movement is resisted by tensile force transmitted through the
struts 120. As is discussed further below, the struts may include
resilient dampers to smoothly absorb the recoil forces and limit
peak force loads transferred to the building. An exemplary recoil
is limited/constrained to a value of less than about 10 cm (e.g. a
value in the range of 1-6 cm, more narrowly 2.5-5 cm).
[0047] The thermally-induced vertical movement of the vessel 20 may
tend to cause associated local vertical movement of the conduit.
Even if this can be partially matched by compliance in the hanger
100, it may be impractical to entirely so address. The result is
that the conduit will tend to rotate to a slightly outlet-down
orientation. A rigid mounting of the conduit to the vessel would
potentially interfere with proper conduit operation across the
anticipated range of vessel vertical displacement. Also, there may
be relative horizontal displacement. Accordingly, referring to FIG.
3, the exemplary apparatus includes means for coupling the conduit
to the vessel so as to accommodate relative longitudinal movement
(e.g., the recoil) and relative angular movement (e.g., associated
with vertical thermal expansion of the vessel or other vertical or
horizontal relative movements). The exemplary means includes a
penetration conduit 150 which may be rigidly mounted to the wall
24. For example, the penetration conduit 150 may be in a friction
fit or an interference fit with the outer layer 26 or may be
secured thereto via brackets or other mounting elements. The
exemplary penetration conduit 150 includes an upstream mounting
flange 152 outside the vessel. A tubular portion 154 extends from
the mounting flange 152 through the wall 24 to an exemplary
downstream/outlet end 156 (e.g., a rim). A downstream end portion
155 of the nozzle at the outlet 40 may protrude beyond the rim
156.
[0048] Referring to FIG. 5, an annular space 160 between the
interior surface 162 of the tubular portion 154 and the exterior
surface 164 of the conduit downstream portion 74 may have
sufficient radial span DR to accommodate relative angular movement
of the combustion conduit 36 relative to the penetration conduit
150 and wall 24. The relative angular movement may include movement
characterized by rotation about a horizontal transverse axis (e.g.,
associated with a pure vertical movement of the vessel relative to
one or more upstream support locations of the conduit). The
relative angular movement may include movement characterized by
rotation about a vertical transverse axis (e.g., associated with a
pure horizontal movement of the vessel relative to one or more
upstream support locations of the conduit). In addition to these
respective pitch and yaw movements, there, potentially may be a
roll movement about a longitudinal axis. The span DR may also be
effective to accommodate transverse translation movements of up to
DR. An exemplary range of angular movement is up to 5.degree. in
any direction (for a total range of 10.degree.) from a neutral
coaxial condition (e.g., to 0.5-5.degree. in any direction or, more
narrowly, 1-4.degree.).
[0049] The space 160 may be sufficiently sealed to limit
exfiltration (outward flow of gases from the vessel interior if a
positive pressure system) and/or infiltration (inward flow of air
in the case of a negative pressure system). To do this, a closure
plate 170 is positioned outside the vessel to provide a higher
degree of relative sealing between the penetration conduit and
combustion conduit than would be associated with the radial gap of
span DR. Referring to FIGS. 4 and 5, in the exemplary
implementation, the plate 170 has a central aperture 172 which
closely accommodates the exterior surface 174 of the conduit
downstream portion 74. An exemplary accommodation is a close radial
sliding fit (much closer than DR). However, for a positive pressure
system, in particular, the gap may be closed (e.g., by a
sealing/structural weld). The exemplary plate 170 is formed in two
180.degree. segments permitting easy assembly over the combustion
conduit. The close accommodation of the plate 170 to the combustion
conduit requires that relative angular movement between the plate
170 and the flange 152 be accommodated. As seen in FIG. 5, this
relative movement may be accommodated by a flexible member 180. An
exemplary flexible member 180 is formed as an expansion joint.
[0050] An exemplary expansion joint is a single or multiple arch
elastomeric expansion joint. The illustrated expansion joint is a
single arch, doubly flanged expansion joint such as is available
from The Mercer Rubber Company of Hauppauge, N.Y., US. The
exemplary expansion joint 180 has a flexible arch 182 between a
first flange 184 and a second flange 186. The first flange 184 is
bolted to the plate 170. The second flange 186 is bolted to the
flange 152. The arch may flex to accommodate the relative angular
movement. In implementations including those with a fixed
non-sliding fit between the plate 170 and the combustion conduit
36, the arch 182 may also accommodate relative longitudinal
displacement. Metallic expansion joints may, however, be used
(e.g., where advantageous due to high temperature exposure).
[0051] For insulation and further sealing, insulation material 190
is positioned within the annular space 160. Exemplary insulation
material comprises fibrous material such as a batt or mat of
mineral wool and/or glass fiber which also provides a degree of
thermal insulation. The material may be longitudinally captured
between the plate 170 and an annular clamp 192 (e.g., a stainless
steel band clamp clamping an end portion of the insulation batt/mat
to the conduit downstream portion 74). With sliding fit between the
plate 170 and the conduit 36, relative longitudinal recoil movement
of the combustion conduit 36 relative to the wall will be
associated with telescoping movement of the downstream portion 74
relative to the penetration conduit 150. The initial recoil may
longitudinally compress the insulation 190. A return may re-expand
the insulation.
[0052] For damping recoil and providing a return force, FIGS. 6 and
7 show damper units 200 which may serve as the joints 126 and/or
128. Each damper unit has a threaded first end portion 202 and a
ball-carrying second end portion 204 (i.e., for forming a ball
joint). In the exemplary damper unit 200 one of the end portions
forms a piston whereas the other forms a cylinder. The exemplary
first end portion 202 is formed on a first shaft having an opposite
end secured (e.g., threaded) into a piston head 206. The exemplary
second end portion 204 is along a second shaft whose opposite end
is secured to a cylinder 210. Within the cylinder 210, at opposite
ends of the head 206 are resilient (e.g., rubber or elastomer)
disks 212 and 214. In the exemplary configuration, extension of the
damper resiliently compresses the disk 212 whereas compression
resiliently compresses the disk 214. The disks 212 and 214 may be
preloaded (i.e., both are under compression when there is no net
compressive or tensile force across the damper unit 200). With the
exemplary damper unit 200, recoil of the conduit further compresses
the disk 214, absorbing the recoil energy and, then, at least
partially relaxing to return the combustion conduit to its initial
position.
[0053] Alternative dampers may be hydraulic snubbers as are
available from Piping Technology&Products, Inc. of Houston,
Tex. Other devices are available from Taylor Devices Inc. of North
Tonawanda, N.Y. as are used in aircraft landing gear shock
absorbers. These may be particularly relevant in systems absorbing
recoil via compression rather than tension.
[0054] Referring back to FIGS. 1 and 2, the struts 120 have
sufficient length to accommodate vertical movement by pivoting at
axes of the coupling elements 132 while not substantially affecting
the longitudinal position of the conduit 36 relative to the wall
24. FIGS. 8 and 9, however, show an alternative configuration
wherein a sliding thrust joint 250 is provided. The joint 250 can
vertically slide along fixed building structures such as a vertical
I-beams (posts) 252 and 254 to accommodate vertical movement.
Recoil thrust loads are transferred through the joint 250 to the
structure 252 and 254.
[0055] FIG. 9 shows respective posts 252 and 254 on opposite sides
of the conduit 36. The exemplary joint 250 includes pieces of low
friction material 256 and 258 respectively sliding along the
downstream faces of the downstream flanges of the posts 252 and
254. Exemplary low friction material is polytetrafluoroethylene
(PTFE) or an ultra high molecular weight (UHMW) plastic material.
The low friction material is sandwiched between the associated post
flange and an associated robust thrust plate 260 and 262. Exemplary
thrust plates may be similarly formed to the plates 140 and 142 of
the first embodiment. Exemplary thrust plates are integrated with a
flanged pipe joint 266 between two segments of the conduit 36.
Retainer brackets 270 and 272 may capture outboard edges of the
respective post flanges to help guide vertical movement.
[0056] FIGS. 10 and 11 have separate plates 260 and 262 attached to
the back face of the downstream flange 280 of one of the conduit
segments (mated to the upstream flange 282 of the next segment).
FIGS. 12 and 13 show an individual one of the plates 260, 262 as
including two through-holes 283 for bolting with the flanges along
the bolt circle of the flanges and two additional holes 284 for
mounting the coupling elements 130 or the low friction material
256, 258 (not shown). FIGS. 14-16 show alternate mounting
configurations for the coupling elements 130 or the low friction
material 256, 258.
[0057] FIGS. 17 and 18 show an alternate plate configuration
wherein plates 300 and 302 replace plates 260 and 262. The plates
300 and 302 are welded to the OD of the flange 280.
[0058] FIGS. 19 and 20 show a single plate 310 having lateral
portions 312 and 314 which respectively replace the plates 260 and
262. The plate 310 is shown sandwiched between the flanges 280 and
282, having a central aperture 316 and a bolt hole circle 320
corresponding to those of the flanges 280 and 282 and receiving the
bolts securing the flanges 280 and 282. Each of the three exemplary
configurations may have different advantages. The welded
construction of FIGS. 17 and 18 allows easy retrofitting without
need to remove any bolts from the flanges 280 and 282. However, the
welds are directly loaded by the recoil force. Also, the loadpath
of the recoil force is spaced outboard of the flange outer diameter
(OD). This relatively large radial spacing may cause undesirably
high bending loading on the flange 280. The FIGS. 10 and 11 plates
may require only partial unbolting and without need to separate the
flanges 280 and 282. The force path is brought radially inward and
may act more directly against the faces of the flanges, thereby
decreasing chance of damage to the flanges. The FIGS. 19 and 20
embodiment may have a radially outboard force transmission but more
evenly circumferentially distributes this force to the associated
moments. However, in a retrofit application, it requires full joint
disassembly. It may also require use of an additional gasket and
replacement of relatively short bolts with relatively longer
bolts.
[0059] Referring to FIGS. 21 and 22, an alternative embodiment of
the damping unit 400 is shown. The unit 400 comprises a plurality
of cylindrical elastomer bumpers 491, such as model number TCB-2
supplied by EFDYN. As seen in FIGS. 21 and 22, four bumpers 491 are
arranged along a rod 493 which is threaded into a standard load
strut 420. Referring to FIGS. 23 and 24, the thrust plates 460 and
462 attach to the rear flange 480 of the combustor conduit 436. The
thrust plates 460 and 462 are similar to the thrust plate discussed
in connection with the previous embodiments with an aperture 497
provided for the rod 493 instead of connecting elements 130 or low
friction material 256, 258. Referring back to FIGS. 21 and 22, each
thrust plate 460 and 462 is clamped between two of the elastomer
bumpers 491. A small preload is applied to the bumpers 491 by nut
and washer assemblies 494 on each side. Each nut and washer
assembly 494 includes two nuts 495 having a split ring style lock
washer 496 between them. Tightening the two nuts 495 together locks
them in place on the threaded rod 493.
[0060] The elastomer bumpers 491 arranged in this fashion act as a
spring/damper system in both recoil (from the initial detonation
thrust load) and in rebound as the kinetic energy absorbed by the
bumpers 491 is released and pushes the combustor conduit 436 back
toward the vessel wall 424.
[0061] The elastomer bumpers 491 having a wide range of load
ratings may be selected for different combustor conduit diameters
and thrust loads. Accordingly, this damping unit is easily scalable
up and down for various combustor diameters and thrust loads.
[0062] The damping unit 400 has been demonstrated in the field and
is capable of installation as a retrofit to an existing sootblower
or as part of a new installation. Testing in the field for a twelve
inch (12'') diameter combustor conduit showed about a half inch
(0.5'') total recoil from the initial blast, with a sinusoidal
decaying motion of the combustor that was completely damped to rest
in four to five cycles of motion. The field testing showed nearly a
reduction factor of four (4) in load transmitted through the struts
to the vessel building structure when the elastomer bumpers 491
were utilized. This reduction is very significant as it greatly
reduces the amount of local reinforcement customers must add to
their vessel building structure for mounting of combustors.
[0063] One or more embodiments of the present invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. For example, the invention may be adapted
for use with a variety of industrial equipment and with variety of
soot blower technologies. Aspects of the existing equipment and
technologies may influence aspects of any particular
implementation. Accordingly, other embodiments are within the scope
of the following claims.
* * * * *